793.37

Model 793.37 Resonance Search and Resonance Fatigue

l

100-017-294 F

Copyright information © 2005 MTS Systems Corporation. All rights reserved.

Trademark information MTS, RPC, Temposonics, and TestWare are registered trademarks of MTS Systems Corporation.

FlexTest, MPT, Profile Editor, Station Builder, Station Manager, and TestStar are trademarks of MTS Systems Corporation.

Lotus 1-2-3 is a registered trademark of the Lotus Development Corporation.

Adobe is a registered trademark and Acrobat is a trademark of Adobe Systems Incorporated.

Microsoft and Windows NT are registered trademarks of the Microsoft Corporation.

Contact information MTS Systems Corporation14000 Technology DriveEden Prairie, Minnesota 55344-2290 USAToll Free Phone: 800-328-2255 (within the U.S. or Canada)Phone: 952-937-4000 (outside the U.S. or Canada)Fax: 952-937-4515E-mail: [email protected]://www.mts.com

ISO 9001 Certified

Publication information Manual Part Number Publication Date

100-017-294 A February 2000

100-017-294 B May 2000

100-017-294 C November 2000

100-017-294 D July 2001

100-017-294 E October 2004

100-017-294 F October 2005

793.37 Resonance Search and Fatigue Contents 3

Contents

Preface 5

Conventions 6Technical Support 8

Introduction 13

About 793.37 Resonance Search 14About 793.37 Resonance Fatigue 16Working with MultiPurpose TestWare 19Hardware Configuration 20Initial Station Builder Settings 21MPT Procedure Settings 23

Resonance Search Process 25

Path and Purpose 26Control Tab 27Search Tab 30

About Sweep Types 34Analysis Tab 36Destination Tab 41Output Units Tab 42Conditions Tab 43General Tab 44

793.37 Resonance Search and FatigueContents4

Resonance Fatigue Process 45

Path and Purpose 46Control Tab 47Search Tab 52Schedule Tab 53Destination Tab 56Output Units Tab 57General Tab 59

Run-time Displays 61

Resonance Search 62Run-time Window 62Run-time Charts 64

Resonance Fatigue 69Run-time Window 69Run-time Charts 72

Test Data Files 73

About Data Files 74Resonance Search 76

Specimen Data Spreadsheet Format 76Time Data Spreadsheet Format 78

Resonance Fatigue 79Specimen Data Spreadsheet Format 79

Elastomer Configure Program 81

Open the Configure Dialog 82Configure Window Settings 83

793.37 Resonance Search and Fatigue Preface 5

Preface

Safety first! Before you attempt to use your MTS product or system, read and understand the Safety manual. Like an automobile, your test system is very useful—but if misused, it is capable of deadly force. You should always maintain a healthy respect for it.

Improper installation, operation, or maintenance of MTS equipment in your test system can result in hazardous conditions that can cause severe personal injury or death, and damage to your equipment and specimen. Again, read and understand the Safety manual before you continue. It is very important that you remain aware of hazards that apply to your system.

Other MTS manuals In addition to this manual, you might receive additional MTS manuals in paper or electronic form.

If you have purchased a test system, it might include an MTS System Documentation CD. This CD contains an electronic copy of all MTS manuals that pertain to your test system, including controller manuals, hydraulic and mechanical component manuals, assembly drawings and parts lists, and operation and preventive maintenance manuals.

Contents Conventions 6

Technical Support 8

793.37 Resonance Search and Fatigue

Conventions

Preface6

ConventionsThe following paragraphs describe some of the conventions that are used in your MTS manuals.

Hazard conventions As necessary, hazard notices may be embedded in this manual. These notices contain safety information that is specific to the task to be performed. Hazard notices immediately precede the step or procedure that may lead to an associated hazard. Read all hazard notices carefully and follow the directions that are given. Three different levels of hazard notices may appear in your manuals. Following are examples of all three levels.

Note For general safety information, see the Safety manual included with your system.

Danger notices Danger notices indicate the presence of a hazard which will cause severe personal injury, death, or substantial property damage if the danger is ignored. For example:

High intensity light and dangerous radiation are emitted by class 3B lasers.

Viewing a class 3b laser directly or viewing it using optical instruments will cause immediate and severe injury.

Avoid eye or skin exposure to the laser beam. Ensure that all power to the laser is off before attempting any maintenance, service, or adjustment procedures.

Warning notices Warning notices indicate the presence of a hazard which can cause severe personal injury, death, or substantial property damage if the warning is ignored. For example:

Hazardous fumes can accumulate in the test chamber as a result of testing.

Breathing hazardous fumes can cause nausea, fainting, or death.

Ensure that the chamber is properly ventilated before you open the chamber door or put your head or hands into the chamber. To do this, ensure that the temperature controller is off and allow sufficient time for the ventilation system to completely exchange the atmosphere within the chamber.

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Conventions


Caution notices Caution notices indicate the presence of a hazard which will or can cause minor personal injury, cause minor equipment damage, or endanger test integrity if the caution is ignored. For example:

This specimen can develop sharp edges as a result of testing.

Handling the specimen with unprotected hands can result in cuts and slivers.

Always wear protective gloves when you handle the specimen.

Other conventions Other conventions used in your manuals are described below:

Notes Notes provide additional information about operating your system or highlight easily overlooked items. For example:

Note Resources that are put back on the hardware lists show up at the end of the list.

Special terms The first occurrence of special terms is shown in italics.

Illustrations Illustrations appear in this manual to clarify text. It is important for you to be aware that these illustrations are examples only and do not necessarily represent your actual system configuration, test application, or software.

Electronic manualconventions

This manual is available as an electronic document in the Portable Document File (PDF) format. It can be viewed on any computer that has Adobe Acrobat Reader installed.

Hypertext links The electronic document has many hypertext links displayed in a blue font. All blue words in the body text, along with all contents entries and index page numbers are hypertext links. When you click a hypertext link, the application jumps to the corresponding topic.

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Technical Support

Preface8

Technical SupportStart with your

manualsThe manuals supplied by MTS provide most of the information you need to use and maintain your equipment. If your equipment includes MTS software, look for README files that contain additional product information.

If you cannot find answers to your technical questions from these sources, you can use the internet, telephone, or fax to contact MTS for assistance. You can also fill out the Problem Submittal Form that is available on the MTS web site and in the back of many MTS manuals that are distributed in paper form.

Technical supportnumbers

MTS provides a full range of support services after your system is installed. If you have any questions about a system or product, contact MTS in one of the following ways.

MTS web sitewww.mts.com

The MTS web site gives you access to our technical support staff by means of a Problem Submittal Form and a Technical Support link.

• Problem Submittal Form: www.mts.com > Contact MTS > Problem Submittal Form

• Technical Support: www.mts.com > Contact MTS > Technical Support

E-mail: [email protected]

Telephone HELPLine 800-328-2255

Weekdays 7:00 A.M. to 6:00 P.M.,

Central Time

Fax 952-937-4515

Please include an MTS contact name if possible.

Technical Support


Before youcontact MTS

MTS can help you more efficiently if you have the following information available when you contact us for support.

Know your site numberand system number

The site number contains your company number and identifies your equipment type (material testing, simulation, and so forth). The number is usually written on a label on your MTS equipment before the system leaves MTS. If you do not have or do not know your MTS site number, contact your MTS sales engineer.

Example site number: 571167

When you have more than one MTS system, the system number identifies which system you are calling about. You can find your job number in the papers sent to you when you ordered your system.

Example system number: US1.42460

Know information fromprior technical

assistance

If you have contacted MTS about this problem before, we can recall your file. You will need to tell us the:

• MTS notification number

• Name of the person who helped you

Identify the problem Describe the problem you are experiencing and know the answers to the following questions.

• How long has the problem been occurring?

• Can you reproduce the problem?

• Were any hardware or software changes made to the system before the problem started?

• What are the model and serial numbers of the suspect equipment?

Know relevant computerinformation

If you are experiencing a computer problem, have the following information available.

• Manufacturer’s name and model number

• Operating software type and service patch information. Examples:

– Windows XP Service Pack 1 (SP1)

– Windows 2000 Service Pack 3 (SP3)

– Windows NT 4.0 Service Pack 7 (SP7)


Technical Support

Preface10

• Amount of system memory. Example: 640 MB of RAM.

• Amount of free space on the hard drive in which the application resides. Example: 11.2 GB free space, or 72% free space.

• Current status of hard-drive fragmentation. Example: 3% total fragmentation.

Know relevant softwareinformation

For software application problems, have the following information available.

• The software application’s name, version number, build number, and if available, software patch number. This information is displayed briefly when you launch the application, and can typically be found in the “About” selection in the “Help” menu.

Example: Station Manager, Version 3.3A, Build 1190, Patch 4

• It is also helpful if the names of other non-MTS applications that are running on your computer, such as screen savers, keyboard enhancers, print spoolers, and so forth are known and available.

If you contact MTSby phone

Your call will be registered by a HELPLine agent if you are calling within the United States or Canada. Before connecting you with a technical support specialist, your agent will ask you for your site number, name, company, company address, and the phone number where you can normally be reached.

Identify system type To assist your HELPLine agent with connecting you to the most qualified technical support specialist available, identify your system as one of the following types:

• Electromechanical materials test system

• Hydromechanical materials test system

• Vehicles test system

• Vehicles component test system

• Aero test system

Technical Support


Be prepared totroubleshoot

Prepare yourself for troubleshooting while on the phone.

• Call from a telephone close to the system so that you can try implementing suggestions made over the phone.

• Have the original operating and application software media available.

• If you are not familiar with all aspects of the equipment operation, have an experienced user nearby to assist you.

Write down relevantinformation

Prepare yourself in case we need to call you back.

• Remember to ask for the notification number.

• Record the name of the person who helped you.

• Write down any specific instructions to be followed, such as data recording or performance monitoring.

After you call MTS logs and tracks all calls to ensure that you receive assistance and that action is taken regarding your problem or request. If you have questions about the status of your problem or have additional information to report, please contact MTS again.

Problem SubmittalForm in MTS manuals

In addition to the Problem Submittal Form on the MTS web site, there is also a paper version of this form (postage paid) in the back of many MTS manuals. Use this form to communicate problems you are experiencing with your MTS software, hardware, manuals, or service. This form includes check boxes that allow you to indicate the urgency of your problem and your expectation of an acceptable response time. We guarantee a timely response—your feedback is important to us.


Technical Support

Preface12

793.37 Resonance Search and Fatigue Introduction 13

Introduction

Overview The 790.37 Resonance Elastomer software is a product that can be used with MTS material test systems to describe the dynamic behavior of elastomeric materials and components in the free-end resonant mode. The Resonance Elastomer software includes two processes for use with the MultiPurpose TestWare software application.

• The Resonance Search process performs a frequency sweep to determine the resonant frequency. This process can also plot run-time data.

• The Resonance Fatigue process performs a frequency sweep to determine the resonant frequency, maximum amplification or maximum phase difference. Once the frequency sweep identifies the required parameter, a series of cycle blocks are applied to the specimen while maintaining the desired resonance relationship.

Contents About 793.37 Resonance Search 14

About 793.37 Resonance Fatigue 16

Hardware Configuration 20

Initial Station Builder Settings 21

MPT Procedure Settings 23


About 793.37 Resonance Search

Introduction14

About 793.37 Resonance SearchModel 793.37 Resonance Search is a MultiPurpose Testware (MPT) process used with MTS material test systems to identify resonant behavior.

The process This is a largely self-contained process. You can create a test procedure containing just one Resonance Search process. This process includes:

• Function generation

• Test condition definition

• Amplitude compensation

• Tolerance control

• Dwell times

• Data acquisition and analysis

• Data display, plotting, and file output

How it works The Resonance Search process applies a frequency sweep, in discrete steps, to a specimen. The process acquires, plots, and saves data about the specimen’s phase and acceleration response to the sweep.

A sweep consists of one or more sweep steps. Each step has a sweep type selection. This selection determines how the step’s start frequency increments. The start frequency increments until it reaches the step’s end frequency.

Within a step there can be one or more conditions. Each increment of the start frequency produces a new condition within the step. The sweep type selected to increment the start frequency determines the number of conditions within the step. A step’s start frequency can be fixed or it can increment linearly or logarithmically.

Each condition within a step has the same dwell duration, dwell type and fixed amplitude. Data gets collected at each condition. A dwell time at the condition’s specified frequency can precede data collection.

The figure below shows a Resonance Search process sweep step having 50 Hz, 60 Hz, and 70 Hz test conditions. Each condition has an identical dwell period. Events A through D repeat for each test condition.

About 793.37 Resonance Search


A Achieve Dynamic Amplitude

The system achieves the required dynamic amplitude. If tolerance checking is turned on, the system uses amplitude and phase control (APC) to achieve the required amplitude.

B Dwell at Frequency

If a dwell is specified, the system cycles at the required frequency. Dwell is defined as either time or a number of cycles.

C Acquire Data

The system acquires acceleration and auxiliary data from selected channels. Data collection can be automatic or defined in terms of cycles.

D Process Data

The system processes acquired data by:

• Correcting timed data for amplitude roll-off and phase angle lag

• Updating run-time windows

• Writing data to disk

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About 793.37 Resonance Fatigue

Introduction16

About 793.37 Resonance FatigueModel 793.37 Resonance Fatigue is a MultiPurpose Testware (MPT) process used with MTS material test systems to identify resonant behavior.

The process Resonance Fatigue process performs a continuous frequency sweep between the start and end frequencies to locate phase/frequency at the specified search criteria (defined phase, maximum phase, or maximum amplification). Once the frequency sweep identifies the required parameter, a series of cycle blocks are applied to the specimen while maintaining the desired phase.

How it works The Resonant Fatigue process searches at a fixed amplitude through a frequency range for the search parameter and then exercises the specimen by running a sequence of cyclic commands. The search parameters are:

• specified phase

• maximum phase

• maximum amplification

Note Amplification is defined as the ratio of output acceleration over the input acceleration,

A run-time window allows you to control certain aspects of the test and view real-time data. With this window you can interrupt the current block, continue executing this block or skip to the next block.

During fatigue cycles, the software maintains the desired phase by performing fine adjustments to the control frequency.



This is an example of a search for the resonant phase.

Here is a simple, coarse frequency sweep from 50 hertz to 70 hertz in 10 hertz steps.

The resonant search zooms into a sub-range of the frequency to find the resonant frequency.

Once the resonant frequency is found, a series of cyclic blocks are applied to the specimen.

1. Perform a Sweep

The process enters the search mode by zeroing the differential pressure in the actuator and sets the amplitude specified in the Control Definition window.

The process starts cycling at the starting frequency until it achieves the dynamic amplitude defined for the sweep in the Search Definition window. Once the amplitude is within the specified tolerance, frequency is evaluated for resonance (or the selected search property). Each frequency step is checked. If the selected search property is not detected, the process ends.

Specified phase ormaximum amplification

The process determines a smaller range between two of the steps in the frequency sweep.

Maximum phase The process determines the frequency with the maximum phase.

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Introduction18

2. Zoom into the Search Property

Specified phase ormaximum amplification

The process begins a second level search of the smaller range (determined above). The second level search checks the mid-point frequency of the range and determines if the next check will be above or below the mid-point frequency. This cuts the smaller range in half. The next midpoint is checked in the same fashion. This continues until a frequency within the frequency resolution is detected.

Maximum phase The process begins a second level search by checking a frequency above the target frequency and a frequency below the target frequency. Comparing the three frequencies determine where the next checks should be made. This continues until a frequency can be found within the required frequency resolution.

3. Perform a Cyclic Fatigue Schedule

After the determination of the selected search property, the process begins to exercise the specimen using the parameters in the Schedule Definition window. In this window you specify test blocks. In each block you can specify a new amplitude and the number of cycles at that amplitude.

Throughout the schedule the process adjusts the frequency to maintain the desired phase angle.

Working with MultiPurpose TestWare


Working with MultiPurpose TestWareThe MultiPurpose TestWare application is a collection of test processes. They are available for selection in the Process Types palette.

After you install Resonance process software, you will find its icons in the Elastomer section of the Process Types palette.

MPT knowledge This manual assumes you have a working knowledge of MPT. This knowledge includes:

• How to use MPT processes and controls to create, edit, and execute test procedures

• How to use specimen directories to record test procedures and retrieve test data

Resonance process icons


Hardware Configuration

Introduction20

Hardware ConfigurationThe Resonance processes requires:

• An input sensor which can be:

– A linear variable displacement transducer (LVDT) mounted inside the actuator.

– An angular displacement transducer (ADT) mounted inside the actuator.

– An accelerometer mounted on the actuator’s piston rod.

• A specimen mounted accelerometer for the output sensor.

• A specimen attached only to the actuator’s piston rod.

• A crosshead positioned to allow actuator travel at maximum test amplitudes.

Initial Station Builder Settings


Initial Station Builder SettingsBefore you can use the Resonance Search process, you must use the Station Builder application to define the initial software settings and save them in a configuration file.

At a minimum you must define the following:

• All the input signals your test requires

• A control channel

• Control modes for the control channel

Input signals Define input signals as follows:

• Define the input signal from a linear variable displacement transducer (LVDT) as length or displacement.

• Define the input signal from an angular displacement transducer (ADT) as angle or rotation.

• Define the input accelerometer. If an accelerometer is not available, an LVDT can be used.

• Define the output accelerometer.


Initial Station Builder Settings

Introduction22

Control channel Define one control channel.

Control modes Define these control modes for the control channel:

• Length or angle (PIDF)

• Force and length (POD)

Tuning You must use the Station Manager application to properly tune and set limits for each control channel. Parameters must be saved for use with the configuration you have created.

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MPT Procedure Settings


MPT Procedure SettingsYou should check certain settings in the MPT Options Editor window before creating a new process. In the MPT toolbar, click on the Options Editor button to display this window.

1. In this window’s Specimen tab:

A. Select an appropriate Data File Mode.

B. Select an appropriate Data File Format. Select Excel to use the plotting macros described in Chapter 6.

2. In this window’s Execution tab, make appropriate selections.

3. In this window’s Specimen Log tab, set Minimum Severity to Warning to reduce the number of process messages sent to the specimen log.


MPT Procedure Settings

Introduction24

793.37 Resonance Search and Fatigue Resonance Search Process 25

Resonance Search Process

Overview This chapter describes Resonance Search tabs and windows.

Contents Path and Purpose 26

Control Tab 27

Search Tab 30

About Sweep Types 34

Analysis Tab 36

Destination Tab 41

Output Units Tab 42

Conditions Tab 43

General Tab 44


Path and Purpose

Resonance Search Process26

Path and PurposePath MPT Main menu ✞ Process Palette ✞ Select ✞

To display the tabs described in this chapter, drag the Resonance Search process icon from the Process Types palette to the Procedure table. Then double-click the icon.

Purpose See “Introduction” on page 13 for more about the Resonance Search process.

Control Tab


Control Tab

Purpose This tab defines the control parameters used in the Resonance Search process.

Control Tab (part 1 of 3)

Item Description

Control Channel Selects the control channel used in the process.

Control Parameter Selects the parameter used for amplitude control in the process.

Displacement or Acceleration are the choices when the Control Channel selection is an axial channel.

Rotation or Acceleration are the choices when the Control Channel selection is a torsional channel.

Control Mode Selects the control mode used in the process.

Selections available depend on your station configuration.

Tolerance Checking Select to turn on amplitude and phase control (APC). At each condition before dwell and data collection begin, APC converges the actual amplitude to within a tolerance value.


Control Tab


Tolerance Value Defines the limits that the requested amplitude must reach before a condition’s dwell and data collection period begins.

%—Defines the tolerance envelope as a percentage of the requested amplitude.

Unit Value—Defines the tolerance envelope as an absolute value.

Amplitude Compensation Selects the method used to achieve test conditions. This control applies to all dynamic channels. Static channels do not use amplitude compensation.

Off—no compensation method is used. The segment generator produces the channel’s command. This selection disables Drive File and Iteration Gain in this tab and also the Tolerance settings in the Definition/Control tab.

Amplitude/Phase Control (APC)—adjusts the command signal to reach the test condition amplitude and eliminate phase lag.

This selection disables Drive File and Iteration Gain in this tab.

Iterate and save drive file—uses an interative method with a drive file (extension “.d31”) to quickly achieve test conditions.

Iterate and don’t save drive file—uses same iterative method as Iterate and save drive file but does not save drive signal data at the end of the process.

Drive file playback—uses an existing drive file as the command source. No iterations or tolerance checking is done to make sure dynamic amplitudes are reached.

Drive File Displays the Select Drive File window where you can create, select, and name drive files. Always use this window to set the path to the drive file.

Drive files can be saved in their own folder, a specimen folder, or a process folder.

Drive File Name (unlabeled)

Displays the path and file name of the currently selected drive file.

Iteration Gain Sets how quickly the dynamic characterization process achieves test conditions when using the two Iterate methods. At each test condition, the error signal gets multiplied by this value before being added to the command signal.

Typically values are between 0.5 and 0.95.


Item Description

Control Tab


Control Timeout The system begins compensating the amplitude of the drive signal once the feedback signal reaches 50% of the command signal or the specified timeout is reached.

Displacement Feedback Signal

Signal 1

Signal 2

Crossover Frequency

Two signals can be used for displacement feedback. Selecting the same signal for both inputs results in no change in the control loop feedback signal.

Signal 1 can be either Axial Displacement, Input Acceleration, or Output Acceleration.


The Corssover Frequency determined when the process switches from Signal 1 to Signal 2 to provide feedback for the control loop.


Item Description


Search Tab


Search Tab

Purpose This tab defines a Resonance search’s sweep steps.

Search Tab (part 1 of 2)

Item Description

Sweep Steps (unlabeled) Displays the search’s sweep step definitions.

Add Adds a step.

Delete Deletes a step.

Search Tab


Sweep Type Defines how the sweep step increments its Start Frequency. Each increment produces a new condition within a step. The sweep type selected determines the number of conditions within the step.

Fixed—the Start Frequency remains unchanged.

Linear steps per sweep—the Value entry sets the number of steps between the Start and End values.

Linear step—steps the sweep by the Value entry until the End value is reached.

LogX2—the Start Frequency increments by an constant multiplier derived from the Frequency Steps needed to increase the Start Frequency by a magnitude of 2.



Amplitude Sets the sweep step’s amplitude.

Amplitude remains constant for all conditions within a step.

Amplitude Units Sets the amplitude measurement units for all sweep steps.

Start Frequency Sets the sweep step’s starting frequency.

End Frequency Sets the sweep step’s ending frequency.

Frequency Steps In a linear step, it sets the number of frequency increments between the Start Frequency and the End Frequency.

In a logarithmic step, it sets the number of increments it takes the Start Frequency to increase by the selected magnitude. The number of increments is used in determining the constant multiplier for the Start Frequency.

Dwell Type Defines the dwell duration in Cycles or Time.

Dwell Duration Sets how long a condition maintains the frequency required by its sweep step before beginning data collection.

Search Tab (part 2 of 2)

Item Description


Search Tab


Adding a step 1. Click Add to enter a step.

2. Select a Sweep Type.

3. Enter an Amplitude value.

4. Enter a Start Frequency and an End Frequency.

5. Enter the number of Frequency Steps.

6. If needed, enter a Dwell Duration and select the Dwell Units.

7. Click Add to enter another step.

Editing a step 1. Highlight the step you want to edit.

2. Use the Step Definition Controls to edit the step.

Deleting a step 1. Highlight the step you want to edit.

2. Click Delete to remove the step.

Sweep step example These Search tab settings produce a sweep step with three conditions. All conditions have the same amplitude and dwell time. Condition 1 is at 50 Hz, condition 2 is at 60 Hz, and condition 3 is at 70 Hz.

Search Tab


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Search Tab


About Sweep Types

Fixed In a step whose Sweep Type is Fixed, the frequency remains unchanged. The sweep step has one condition.

Linear sweeps Linear sweeps change by a constant increment:

There are two types of linear sweeps:

• Linear steps per sweep

• Linear step

When you select Linear steps per sweep, the value entered sets the number of steps in the sweep. The formula below uses this value to determine the increment per step:

Example: Your sweep has a Start value of 5, an End value of 35, and a Linear steps per sweep value of 3. The resulting sweep has steps at 15, 25, and 35.

When you select Linear step, the value entered sets how much the sweep value changes with each step:

Example: Your sweep has a Start value of 5, an End value of 35, and a Linear step value of 5. The resulting sweep has steps at 5, 10, 15, 20, 25, 30, and 35.

Logarithmic sweeps In a step whose Sweep Type is LogX2, LogX8, or LogX10, the frequency changes by a constant multiplier:

LogX2 This formula determines the frequency’s constant multiplier when the step’s Sweep Type is LogX2:

new value previous value increment+=

increment per step (Start value End value)–Linear steps per sweep value---------------------------------------------------------------------=

increment per step Linear step value=

new frequency previous frequency constant multiplier×=

Search Tab


Example: A step has a Start Frequency of 1, an End Frequency of 4, and a Frequency Step of 2. This step has 5 conditions with 1, 1.4142, 2, 2.8284, and 4 Hz frequencies.


Example: A step has a Start Frequency of 1, an End Frequency of 64, and a Frequency Step of 3. This step has 3 conditions with 1, 2, 4, 8, 16, 32, and 64 Hz frequencies.


Example: A step has a Start Frequency of 1, an End Frequency of 100, and a Frequency Step of 3. This step has 7 conditions with 1, 2.1544, 4.6416, 10, 21.544, 46.416, and 100 Hz frequencies.

constant multiplier 10

log 2( )frequency steps-------------------------------------⎝ ⎠⎛ ⎞

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log 8( )frequency steps-------------------------------------⎝ ⎠⎛ ⎞

=


1frequency steps-------------------------------------⎝ ⎠⎛ ⎞

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Analysis Tab


Analysis Tab

Purpose This tab selects the signals used for data analysis and the data collection method.

Analysis Tab (part 1 of 2)

Item Description

Channel Definition Selects the signals used for data analysis.

Input Sensors Selects the input acceleration signal.

Radius Enter the linear input accelerometer’s mounting radius.

Torsional testing requires Radius and Radius Units entries to calculate rotary acceleration from linear accelerometer data.

Radius Units (unlabeled)

Select the radius units of measurement for the input and output sensors.

Output Sensors Selects the output acceleration signal.

Invert Output Phase Select to correct 180° out-of-phase problems caused by accelerometer cabling.

Radius Enter the linear output accelerometer’s mounting radius.

Analysis Tab


Data period selection The Resonance Search process acquires data in terms of cycles. The process divides the cycles in which it collects data into timed intervals. It acquires a data point at each interval. The type of test and your system’s performance determine the number of data points collected. Between 75 and 1024 data points are collected at each sweep step.

The Analysis tab’s Data Period selection can be either Cycles or Automatic.

Cycles The Data Period selection of Cycles allows you to enter a specific number of data cycles. This selection puts a higher priority on acquiring data within the number of cycles specified than in maintaining frequency tolerance.

However, the Cycles selection requires that the process acquire at least 75 data points during each sweep step. To do this, the process may increase the frequency tolerance to allow 75 data points to be acquired during the cycles specified. It may also increase the number of data cycles if it cannot collect 75 data points within the cycles specified.

Note Data scatter results when you specify less than 15 cycles and test at frequencies where the process collects less than 300 data points. Always specify at least 15 data cycles at higher frequencies.

Automatic The Data Period selection of Automatic lets the process set the number of data cycles. This selection puts a higher priority on maintaining frequency tolerance and obtaining a minimum 350 data points than in minimizing the number of data cycles.

This table shows the initial number of data cycles in which the process will try to acquire 350 data points. Higher test frequencies result in more data cycles.

Auxiliary Check to enable monitoring of an unused signal.

Auxiliary Signal (unlabeled)

Select an unused signal to monitor. Select any signal not used for input or output acceleration.

Data Period Determines the data collection period.

Automatic—the process uses the sweep step frequency to set the number of cycles in which it collects data.

Cycles—you set the number of segments or cycles in which the process collects data.

Analysis Tab (part 2 of 2)

Item Description


Analysis Tab


Actual vs. requested Data acquired at each sweep step must meet these two requirements:

• There must be at least 75 data points

• The step’s frequency must be within a window determined by a frequency tolerance algorithm

When the process prepares to acquire data, it works through a series of steps to see if it can met these requirements. If they cannot be met, the process adds a data cycle to the cycles requested. The process goes through the steps again to see if it can meet the these requirements. The process continues adding data cycles until it satisfies the data point and frequency requirements.

As a result of this process, the actual number of executed data cycles and frequencies may differ from what you request.

Frequency tolerance The following frequency tolerance ranges for a standard data acquisition board optimize resolution within the selected range:

• For requested frequencies less than or equal to 10 Hz, the tolerance is 0.3% of the requested frequency.

• For requested frequencies greater than 10 Hz or less than or equal to 50 Hz, the tolerance is 0.5% of the requested frequency.

• For requested frequencies greater than 50 Hz, the tolerance is 0.75% of the requested frequency.

• The maximum frequency tolerance is 0.7 Hz.

Program logic toacquire data cycles

This table shows the program logic that determines the actual test frequency, data cycles, and data points with standard data acquisition hardware.

Sweep Step Frequency Minimum Data Cycles≤ 1 Hz 1 Cycle

> 1 Hz 3 Cycles

Where: c = data cycles fr = requested frequency

n = data points fa = actual frequency

tpp = time/point t = frequency tolerance

Analysis Tab


Data cycles/frequencies

These tables show the maximum frequencies at which the desired data cycles can be obtained as a function of a system’s maximum data acquisition rate.

Step Comments

n = c x 100 Initial data point value for a given number of data cycles.

Sets the desired number of data points.

if n > 1024, then n = 1024if n < 512, then n = 512

Verifies that the desired number of data points is between 512 and 1024.

top = c/fr/n Defines the desired time per point.

if 1/tpp > max data acq rate, then tpp = 1/max data acq rate

Sets time per point to the system’s maximum data acquisition rate if necessary. The data acquisition hardware used determines the actual rate.

n = c/fr/tpp Determines the actual number of data points rounded to the nearest integer.

shift tpp to the nearest actual discrete rate

Instruction that shifts the time per point to the nearest discrete rate at which the system’s data acquisition hardware can acquire data.

fa = c/(tpp x n) Calculation of the actual frequency.

if ⎜fa – fr⏐ > t, add 1 to c and try again

Adds one data cycle whenever the actual frequency is not within tolerance.

if n < minimum points add 1 to c and try again

Adds one data cycle when the number of data points acquired are less than the minimum required. The Automatic selection requires at least 350 data points. The Cycles selection requires at least 75 data points.

Maximum Test Frequency Acquired Data Cycles

31.5 1

80.5 2

120 3

156 57


Analysis Tab


Example: A system with a 5000 Hz data acquisition rate can acquire 1 data cycle for frequencies up to 67 Hz. If the desired test frequency was 68 Hz, the system would acquire 2 data cycles.

High speed option TestStar IIs, TestStar IIm and FlexTest GT have a high speed option with a maximum data acquisition rate of 49,152 Hz.

To use this option, an elastomer system must have the following:

• Version 3.0 software

• All Digital Universal Conditioner Rev B (DUCB) conditioners

• An MTS Model 498.96 Processor CPU board

• An MTS Model 793.38 High Speed data Acquisition software option.


43 1

107 2

141 3

180 57


67 1

127 2

156 3

203 57

Destination Tab


Destination Tab

Purpose This tab defines where Resonance Search process data goes.

Timed data If you select Save Time Data, the process saves timed data in a text file. Additional files gets created each time the process runs.

The process places the timed data file in the specimen directory with a “.t37” extension. The first file saved is named time0000.t37, the second file saved is time0001.t37, the third is time0002.t37, and so on.

Analysis Tab

Item Description

Data Header Enter the header that you want to appear in the process data.

Specimen data file Select to save process data in a common specimen data file. Data from other processes in the procedure can be written to this file.

User-specified data file Select to save just the data from this process in a separate file.

User file name (unlabeled)

Enter the name of the user-specified data file. This file is saved in the specimen directory with a “.dat” extension.

Save Time Data Select to save time data to a separate file in the specimen directory.


Output Units Tab


Output Units Tab

Purpose This tab defines the units of measurement used in data and charts.

Output Units Tab

Item Description

UAS Displays the currently selected unit assignment set (UAS).

Current Unit Assignment Set Select to use the UAS chosen at installation or assigned by the Station Builder application to the current configuration.

Other Unit Assignment Set Select to use the alternate UAS chosen in the Unit Assignment Set Open window.

Selecting this button enables Select Other.

Select Other Displays the Unit Assignment Set Open window. This window defines the UAS used when you select Other Unit Assignment Set.

Edit Displays the Unit Assignment Set Editor window. This window edits units used in the currently selected UAS. See the MultiPurpose TestWare manual for more on this window.

Conditions Tab


Conditions Tab

Purpose This display-only tab shows all the sweep step conditions defined using the Control and Search tabs.

Note that sweep conditions get numbered independently of sweep step numbers.


General Tab


General Tab

Purpose This tab sets the general characteristics of the Resonance Search process.

General Tab

Item Description

Name Enter your name for this process. Your name becomes the Procedure table’s Name entry.

Process Enabled Select to enable execution of the process.

Execute Process Sets the number of times the process executes.

Counter Type Selects the type of sequence counter used in the MPT Control Panel.

None—no counter is used. This selection disables Counter Label.

Transient—displays a counter for the process only when it runs.

Fixed—displays a counter for the process throughout the entire procedure.

Counter Label Use to label the transient or fixed counter that appears in the Sequence Counter of the MPT Control Panel. The Name entry becomes the label if you make no entry here.

793.37 Resonance Search and Fatigue Resonance Fatigue Process 45

Resonance Fatigue Process

Overview This chapter describes Resonance Fatigue tabs and windows.

Contents Path and Purpose 46

Control Tab 47

Search Tab 52

Schedule Tab 53

Destination Tab 56

Output Units Tab 57

General Tab 59


Path and Purpose

Resonance Fatigue Process46

Path and PurposePath MPT Main menu ✞ Process Palette ✞ Select ✞

To display the tabs described in this chapter, drag the Resonance Fatigue process icon from the Process Types palette to the Procedure table. Then double-click the icon.

Note In previous versions, this process was called Resonant Dwell, hence the “RD” label in the icon. The process was renamed Resonance Fatigue to better reflect the actual intent of the process.

Purpose See “Introduction” on page 13 for more about the Resonance Fatigue process.

Control Tab


Control TabThis tab defines the control parameters used in the Resonance Fatigue process.


Control Tab



Item Description

Control Channel Selects the name of the dynamic control channel (usually axial or torsional).

Control Parameter Selects the parameter used for amplitude control in the process.

Displacement or Acceleration are the choices when the Control Channel selection is an axial channel.

Rotation (Angle) or Acceleration are the choices when the Control Channel selection is a torsional channel. The torsional channel also requires a radius value for a linear acceleration signal. You must enter the radius from the center of the accelerometer to the center of the piston rod.

Control Mode Selects the control mode used in the process.

Selections available depend on your station configuration.

Tolerance Checking Select to turn on amplitude compensation.The amplitude compensator converges the actual amplitude to within a specified tolerance value.

Tolerance Value Specifies how close the amplitude must be to the programmed amplitude before the process starts the property search or counts fatigue cycles.

%—Defines the tolerance envelope as a percentage of the requested amplitude.

Unit Value—Defines the tolerance envelope as an absolute value.

Amplitude Compensation Selects the method used to achieve test conditions. This control applies to all dynamic channels. Static channels do not use amplitude compensation.

Off—no compensation method is used. The segment generator produces the channel’s command. This selection disables Drive File and Iteration Gain in this tab and also the Tolerance settings in the Definition/Control tab.

Amplitude/Phase Control (APC)—adjusts the command signal to reach the test condition amplitude and eliminate phase lag.

Iterate and don’t save drive file—use the iterative method to quickly converge the amplitude command to the desired amplitude.

Control Tab


Iteration Gain Sets how quickly the dynamic characterization process achieves test conditions when using the two Iterate methods. At each test condition, the error signal gets multiplied by this value before being added to the command signal.

Typically values are between 0.5 and 0.95.

Control Timeout The system begins compensating the amplitude of the drive signal once the feedback signal reaches 50% of the command signal or the specified timeout is reached.

Displacement Feedback Signal

Signal 1

Signal 2

Crossover Frequency

Two signals can be used for displacement feedback. Selecting the same signal for both inputs results in no change in the control loop feedback signal.



The Crossover Frequency determined when the process switches from Signal 1 to Signal 2 to provide feedback for the control loop.

Search Type Selects one of the three search properties. The search properties are:

• Resonant Phase - search resonance frequency at a predefined phase

• Maximum Phase - search resonance frequency at maximum phase

• Maximum Amplification - search resonance frequency at maximum amplification

Resonant Phase Specifies the desired relationship between the input and output signals.


Item Description


Control Tab


DisplacementFeedback Signal

Two signals are provided to accommodate a wide range of testing frequencies. Typically, if the system is being run in displacement control, the LVDT (Axial Displacement) will be used. However, LVDTs have a tendency to roll off at higher frequencies. An accelerometer can also be used for displacement control; however, accelerometers tend to be noisy at lower frequencies. So this section allows you to select an LVDT to control displacement at lower frequencies and then switch to an accelerometer for higher frequency testing.

Phase and amplitudetolerances

The values entered in these fields determine how precisely the process controls phase and amplitude.

• If these values are too low, noise might cause out-of-tolerance conditions resulting in the system continually making minute corrections to compensate for the noise.

• If the values are too high, the level of control will be diminished and the process will not be used to its fullest potential.

Resonance Definition

Input Sensors

Output Sensors

Invert Output Sensor

Auxiliary Channel

Phase Tolerance

Specifies displacement or acceleration for an axial channel. Specifies angle or acceleration for a torsional channel.

The output signal must be an acceleration signal.

Checking this box inverts the output sensor signal.

Enables an additional data channel to be displayed in the run-time window. Typically, this will be associated with temperature readout from a thermocouple.

Enter a value between 0 and 180°. Specifies how precisely the phase must be maintained between the input and output signals. Enter a value between 0 and 180°.

Frequency Resolution Defines the precision of the resonant frequency. It specifies how tightly the search zooms in on the resonant condition. The minimum value is 0.01 Hz.


Item Description

Control Tab


Frequency resolution The frequency resolution value is used to determine a discrete frequency for the property search. It is also used during the execution of the test schedule.

• During the property search the frequency resolution defines how tightly the search “zooms in” on the required frequency.

• During the test schedule the frequency resolution acts as a step increment when tracking the desired phase in the scheduled mode.

• The frequency resolution specifies how fast the controller can track a changing response.

If during the test, the phase angle shifts by a value greater than the phase tolerance (specified above) the frequency will repeatedly step by the amount specified until the phase is again within tolerance.


Search Tab


Search TabThis window defines a frequency sweep to search for a selected property. The selected property can be a specified phase, maximum phase or maximum amplification.

Frequency range The search begins at the specified start frequency. After each test for resonance, the frequency increases by the increment specified for the coarse step frequency. The search continues in this manner until the entire frequency range has been tested and the initial resonance frequency sub-range has been found.

• If the sub-range was not found, the range defined by the Start Frequency/End Frequency was not large enough.

• If the sub-range was found, the search begins to zoom in on the resonance frequency until the specified frequency resolution is satisfied.

Search Tab

Control Function

Dynamic Amplitude Defines the amplitude that the controller commands during the property search.

Start Frequency Specifies the beginning of the frequency sweep. This value must be greater than 0 and less than the end frequency value.

End Frequency Specifies the end of the frequency sweep. This value must be greater than the start frequency and less than 1000.

Frequency Resolution Specifies the value for the frequency step increments.

Schedule Tab


Schedule TabThe Schedule area allows you to create a sequence of cyclic commands (blocks) that fatigue the specimen. The schedule exercises the specimen according to the parameters you specify.

Schedule Tab (part 1 of 2)

Control Function

Block Identifies a block of cycles and its sequence in a fatigue test. Each block is defined by a dynamic amplitude and number of cycles.

Dynamic Amplitude Shows the amplitude for each block.

Cycles Shows the number of cycles for each block.

Block Parameters Use this area to define or edit the amplitude and cycles of a block.


Schedule Tab


Plot Data Decimation A maximum of 1000 data points (by default) can be used for the plot series. When reading maximum data points, data decimation will be used to take every other data point from the current plot series. Data output rate is not affected by the decimation process. You can change the default maximum data points setting using the Elastomer Configure program. See “Maximum plot data points for Resonance Fatigue run-time plot windows” on page 85 for additional information.

Add Inserts the Block Parameters into the schedule. The Add button creates a new block for the schedule and automatically assigns a sequence number to it.

To insert a block between two existing blocks, select the block below where you want the new block. Enter the values in the entry fields. Press on the Add button.

Delete Removes the selected block from the schedule.

Hold Between Blocks Enables the process to pause between blocks and require an operator to proceed.The pause will last until you select Next Block on the Run-time window. You can change the selection for this feature in the Run-time window.

Data Output Rate Specifies the output rate for the MPT data file and the plot data.

Save Test Data Enables the data acquired during the process to be saved as a standard MPT data file.

Plot Selects up to three, predefined run-time plots. Highlight a plot you want to display. All selected plots are automatically displayed when the fatigue cycles begin.

Maximum Series Specifies how many series are shown in the plot window. A series is the data acquired from one block. You can specify up to 24 series.

For example, if three series are specified, All blocks are plotted but only the last 3 blocks are displayed at any given time.

X-Axis Scaling You can specify if the X axis scale of the plot is linear or logarithmic.

Schedule Tab (part 2 of 2)

Control Function

Schedule Tab


Using the window The Schedule area allows you to create a sequence of cyclic commands (blocks) that fatigue the specimen. The schedule exercises the specimen according to the parameters you specify.

Creating a block Enter the Block Parameters values for the Dynamic Amplitude and Cycles. Click the Add button to copy the block parameters to the schedule area. The block parameters are added above the highlighted row. A block number is automatically added to the block parameters to indicate its sequence in the schedule.

To insert a new row between two existing rows, select the row below the location where you want the new row. Enter the values in the entry fields and click on Add. The new row will be displayed and the list renumbered.

Editing a block Select an existing block. The values for that block appear in the Block Parameters entry fields. To make a change, enter the new values.

Deleting a block Select an existing block with the information you want to delete and click the Delete button.


Destination Tab


Destination TabThis tab defines where Resonance Fatigue process data goes.

Analysis Tab

Item Description

Data Header Enter the header that you want to appear in the process data.

Specimen data file Select to save process data in a common specimen data file. Data from other processes in the procedure can be written to this file.

User-specified data file Select to save just the data from this process in a separate file.

User file name (unlabeled)

Enter the name of the user-specified data file. This file is saved in the specimen directory with a “.dat” extension.

Display data from MPT Operator Information process in the run-time chart

Select to display parameters from the Operator Information in the run-time chart. Refer to the Model 793.10 MultiPurpose TestWare User Information and Software Reference manual for additional information.

Output Units Tab


Output Units TabThis tab defines the units of measurement used in data and charts.

Output Units Tab (part 1 of 2)

Item Description

UAS Displays the currently selected unit assignment set (UAS).

Current Unit Assignment Set Select to use the UAS chosen at installation or assigned by the Station Builder application to the current configuration.

Other Unit Assignment Set Select to use the alternate UAS chosen in the Unit Assignment Set Open window.

Selecting this button enables Select Other.


Output Units Tab


Select Other Displays the Unit Assignment Set Open window. This window defines the UAS used when you select Other Unit Assignment Set.

Edit Displays the Unit Assignment Set Editor window. This window edits units used in the currently selected UAS. See the MultiPurpose TestWare manual for more on this window.

Output Units Tab (part 2 of 2)

Item Description

General Tab


General TabThis tab sets the general characteristics of the Resonance Fatigue process.

General Tab

Item Description

Name Enter your name for this process. Your name becomes the Procedure table’s Name entry.

Process Enabled Select to enable execution of the process.

Execute Process Sets the number of times the process executes.

Counter Type Selects the type of sequence counter used in the MPT Control Panel.

None—no counter is used. This selection disables Counter Label.

Transient—displays a counter for the process only when it runs.

Fixed—displays a counter for the process throughout the entire procedure.

Counter Label Use to label the transient or fixed counter that appears in the Sequence Counter of the MPT Control Panel. The Name entry becomes the label if you make no entry here.


General Tab


793.37 Resonance Search and Fatigue Run-time Displays 61

Run-time Displays

Overview This chapter describes run-time windows, plot charts, and other items that can appear during execution of a Resonance Search and Fatigue processes.

Contents Resonance Search 62

Run-time Window 62

Run-time Charts 64

Resonance Fatigue 69

Run-time Window 69

Run-time Charts 72


Resonance Search

Run-time Displays62

Resonance Search

Run-time Window

This window shows resonance search results as the process executes. It displays when you switch from the edit to the execute mode in the MPT Control Panel.

Run-time Window (part 1 of 2)

Item Description

RS <procedure name> Identifies the resonance search process by the name given it in the General tab.

Plot Has Phase, Amplitude, and Amplification menu selections.

Phase—select to display a phase versus frequency plot.

Amplitude—select to display an amplitude versus frequency plot.

Amplification—select to display an amplification versus frequency plot.

Resonance Search


Test Result Displays the current test results.

Last Condition Displays the Frequency, Amplification, Phase, and Damping from the last test condition.

Maximum Amplification—displays the maximum amplification reached and the Frequency, Phase, and Damping at maximum amplification.

Phase—displays the maximum phase reached and the Frequency, Amplification, and Damping at maximum phase.

Damping—displays the maximum damping reached and the Frequency, Amplification, and Phase at maximum damping.

Minimum Amplification—displays the minimum amplification reached and the Frequency, Phase, and Damping at minimum amplification.

Phase—displays the minimum phase reached and the Frequency, Amplification, and Damping at minimum phase.

Damping—displays the minimum damping reached and the Frequency, Amplification, and Phase at minimum damping.

Sweep Status Displays the sweep’s Step and Condition number, the Current Frequency, and the number of Remaining Cycles in the current test condition.

Status Bar Displays status messages during process execution.


Item Description


Resonance Search

Run-time Displays64

Run-time Charts

Purpose Display run-time plots of phase versus frequency, amplitude versus frequency, and amplification versus frequency.

Display options Use Shift + mouse-drag to zoom in on a chart.

Use the r key to reset scaling.

The Chart Properties tab allows you to customize chart colors and plot axes. Right-clicking on a chart and selecting Properties displays this tab. See page 65 for more about this tab.

Resonance Search


Chart Properties/Axis Tab

Purpose This tab customizes plot axes. Right-clicking on a chart and selecting Properties displays this tab.

Chart Properties/Axis Tab (part 1 of 2)

Item Description

Axis Selects the axis to be changed.

Minimum check box Select to auto-scale the minimum value of the selected axis.

Minimum box Displays the minimum value for the selected axis. To enter your own minimum value here, uncheck the Minimum check box.

Maximum check box Select to auto-scale the maximum value of the selected axis.

Maximum box Displays the maximum value for the selected axis. To enter your own maximum value here, uncheck the Maximum check box.

Major Unit check box Select to auto-scale the major unit value for the selected axis.

Major Unit box Displays the major unit value for the selected axis. To enter your own major unit value here, uncheck the Major Unit check box.

Minor Unit check box Select to auto-scale the minor unit value for the selected axis.

Minor Unit box Displays the minor unit value for the selected axis. To enter your own minor unit value here, uncheck the Minor Unit check box.

Origin check box Select to auto-scale the crossing of the selected axis.


Resonance Search

Run-time Displays66

Origin box Displays the crossing value of the selected axis. To enter your own crossing value here, uncheck the Origin check box.

Grid Lines Select to turn on grid lines.

Logarithmic Select to turn on logarithmic scaling.

Reverse Order Select to reverse the axes minimum and maximum values.

Save Defaults Makes this tab’s Grid lines setting and all the Chart Properties/General tab settings the default values for all elastomer process charts.

Chart Properties/Axis Tab (part 2 of 2)

Item Description

Resonance Search


Chart Properties/General Tab

Purpose This tab customizes chart colors and fonts. Right-clicking on a chart and selecting Properties and then General displays this tab.

Chart Properties/General Tab (part 1 of 2)

Item Description

Background Color Displays the color selected for the chart’s background. Clicking on the right button displays the Color window where you can change this color.

Graph Area Color Displays the color selected for the plot’s grid line and text color. Clicking on the right button displays the Color window where you can change this color.

Data Area BG Color Displays the color selected for the plot’s data area background. Clicking on the right button displays the Color window where you can change this color.

Header Color Displays the color selected for the header text. Clicking on the right button displays the Color window where you can change the color.

Footer Color Displays the color selected for the footer text. Clicking on the right button displays the Color window where you can change the color.

Legend Color Displays the color selected for the footer text. Clicking on the right button displays the Color window where you can change the color.

Axis Font Displays the font selected for the axis text. Clicking on the right button displays the Font window where you can change this font.


Resonance Search

Run-time Displays68

Note Choose different chart and text colors. Identical colors will produce illegible charts.

Header Font Displays the font selected for the header. Clicking on the right button displays the Font window where you can change this font.

Footer Font Displays the font selected for the footer. Clicking the right button displays the Font window where you can change this font.

Legend Font Displays the font selected for the legend. Clicking the right button displays the Font window where you can change this font.

Save Defaults Makes this tab’s settings and the Chart Properties/Axis tab’s Grid lines setting the default values for all elastomer process charts.

Chart Properties/General Tab (part 2 of 2)

Item Description

Resonance Fatigue


Resonance Fatigue

Run-time Window

This window shows resonance fatigue results as the process executes. It displays when you switch from the edit to the execute mode in the MPT Control Panel.


Item Description

RS <procedure name> Identifies the resonance search process by the name given it in the General tab.

Plot Fatigue Data This is a menu that can enable up to three run-time plot windows.


Resonance Fatigue

Run-time Displays70

Status The status area monitors three types of information.

Mode: Indicates whether the process is performing a resonant Search or executing the fatigue Schedule.

State: Indicates the current program status — Stopped, Running, Holding, Error, Pausing, or Interrupted.

Motion: Indicates the action of the dynamic actuator in response to process commands — Zeroing, Ramping, Settling, Cycling or Complete.

Control The Control panel allows you to interrupt the test so you can over-ride the phase setting or move to the next block cycle. The control panel includes controls to manually interrupt the process so you can change the process program.

Interrupt Suspends the test so changes can be made.

While in the desired phase search, you can overwrite the phase and restart the search.

While in the maximum phase or maximum amplification search, you can cancel the current search and restart it again.

While in the Schedule Mode you can interrupt the current block of cycles and starts the next block of cycles in the schedule.

Continue Resumes the test from where it was interrupted in the fatigue test or restart the search in the Search mode.

Next Block Skips the remaining cycles in the current block and starts the next block of cycles in the schedule

Exit Ends the process

Desired Phase Over-rides the resonant phase setting in the Control Definition window with the phase setting of this control.

Hold between Blocks

Enables or disables a hold between blocks. When enabled, this feature automatically suspends the test at the end of each block of cycles. You must press Next Block or Exit button to continue. This control is the same control in the Schedule Definition window.

Data The Data panel shows you the programmed levels and the data collected from the test. It also shows which block is being executed, how many cycles are in the block and how many are completed. Due to the required calculations, data in this panel is updated approximately once a second.


Item Description

Resonance Fatigue


Current Freq Shows the frequency that produces the rest of the data in the panel.

Dynamic Amplitude

Shows the amplitude setting for the current cycle block. The value is entered in the Schedule Definition window.

Actual Shows the actual amplitude for the current cycle block.

Input AccelOutput, Accel

Shows the current output of these sensors.

Amplification Shows the amplification (ratio) derived from the input and output acceleration sensors.

Aux Input 2 When enabled, it shows the current value of the auxiliary channel.

Desired Phase Shows the phase that will be used during the fatigue test.

Current Phase Shows the current phase angle of the test.

Fatigue Block # Shows the block number of the current cycle block being executed.

Fatigue Cycles Shows the number of cycles in the specified for the current block.

Completed Cycles Shows how many cycles of the current block are done.


Item Description


Resonance Fatigue

Run-time Displays72

Run-time Charts

Amplification plot

Amplification plots display the ratio between the input amplification and the amplitude as a function of cycles

Frequency plot

Frequency plots the frequencies as a function of cycles.

Auxiliary plot

This plots the auxiliary input 2 signal as a function of cycles.

793.37 Resonance Search and Fatigue Test Data Files 73

Test Data Files

Overview This chapter describes Resonance Search data files and their spreadsheet formats.

Contents About Data Files 74

Resonance Search 76

Specimen Data Spreadsheet Format 76

Time Data Spreadsheet Format 78

Resonance Fatigue 79

Specimen Data Spreadsheet Format 79


About Data Files

Test Data Files74

About Data Files

Specimen and userdata files

Resonance Search process test data can be written to both specimen data files and user files. Destination tab selections determine where data files go:

• Select this tab’s Specimen data file to write data from this process to a common specimen data file. This file also has data from other processes in your procedure.

• Select this tab’s User File to write just Resonance Search process data to a separate data file.

User and specimen data files have “.dat” extensions. They get written to the currently selected specimen directory.

Time data files(Resonance Search only)

Select this tab’s Save Time Data to write time data to a separate file.

Time data files have “.t37” extensions. They get written to the currently selected specimen directory.

Display data from MPTOperator Information

process in the run-timechart

Select to display parameters from the Operator Information in the run-time plots. Refer to the Model 793.10 MultiPurpose TestWare User Information and Software Reference manual for additional information.

About Data Files


Data file formats

Use the Specimen tab in the MPT Options Editor to:

• Append or Overwrite data in specimen and user data files.

• Select Plain, Lotus, or Excel data file formats.

For more about this tab, see the MultiPurpose TestWare manual.

Acquiring data As the test runs, the system processes results on a condition-by-condition basis. The system writes the results to a data file after each test condition executes.

If you stop the test prematurely or if a limit is exceeded, data files will retain the data gathered before the test was stopped.


Resonance Search

Test Data Files76

Resonance Search

Specimen Data Spreadsheet Format

Columnorganization

The Resonance Search process specimen data file produces 12 columns of spreadsheet data. Auxiliary channels add additional columns of data.

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Specimen Data Spreadsheet Columns (part 1 of 2)

Column Description

Step The sweep step number. This number repeats itself for every test condition in the sweep step.

Condition The number of each sweep step condition completed during the test. Sweep step conditions are numbered independently of sweep steps.

Specified Frequency The frequency specified for the sweep step.

Actual Frequency The actual frequency of the sweep step.

Actual Amplitude The actual amplitude attained during the sweep step.

Amplification The ratio of the output channel’s amplitude to the input channel’s amplitude.

Phase The phase relationship between the input channel and the output channel.

Damping The energy dissipation ratio between the input channel and the output channel.

Resonance Search


Input Amplitude Amplitude measured on the input channel.

For an axial channel, the input amplitude is expressed in units of:

•Linear acceleration, measured by an accelerometer.

•Displacement, measured by an linear variable displacement transducer (LVDT).

For a torsional channel, the input amplitude is expressed in units of:

•Rotary acceleration, measured directly by a rotary accelerometer.

•Rotary acceleration, derived from a linear accelerometer’s output and the radius from the center of the accelerometer to the center of the piston rod.

•Rotation, measured by an angular displacement transducer (ADT).

Output Amplitude The amplitude measured on the output channel.

For an axial channel, the output amplitude is expressed in units of linear acceleration, measured by an accelerometer.

For a torsional channel, the output amplitude is expressed in units of:

•Rotary acceleration, measured directly by a rotary accelerometer.

•Rotary acceleration, derived from a linear accelerometer’s output and the radius from the center of the accelerometer to the center of the piston-rod.

Auxiliary Channel Data Data from auxiliary channels.

Data Cycles The number of cycles in which data was acquired.

Data Points The number of data points acquired in the step.


Column Description


Resonance Search

Test Data Files78

Time Data Spreadsheet Format

Columnorganization

The Resonance Search process time data file produces four columns of spreadsheet data.

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Time Data Spreadsheet Columns

Column Description

Condition and Time Has the actual frequency, number of data points and data cycles for each sweep step, followed by the collection time of each data point.

Actual Amplitude Has the actual amplitude recorded at each data point.

Input Amplitude Has the actual input amplitude recorded at each data point.

Acceleration Output Amplitude

Has the actual output acceleration amplitude recorded at each data point.

Resonance Fatigue


Resonance Fatigue

Specimen Data Spreadsheet Format

Columnorganization

The Resonant Fatigue process produces 13 columns of data when an auxiliary channel is monitored. The data collected by the Resonant Fatigue process includes the following:


Column DescriptionTime The time column indicates the time in seconds since Reset and Run were

selected from the TestWare-SX Execute Procedure windowFatigue Block # This column indicates either Search or the block numberFrequency The actual frequency of the test condition.Specified Amplitude The amplitude entered in the Schedule Definition window for the test

condition.Dynamic Amplitude Dynamic displacement or rotation amplitude actually attained during the

test condition.


Resonance Fatigue

Test Data Files80

Input Amplitude

For axial channels

For torsional channels

The amplitude measured on the input channel. The program may convert this amplitude to a dimension appropriate for the selected control channelThe input amplitude may have dimensions of:

• Linear acceleration, measured by an accelerometer.• Displacement, measured by an LVDT (Linear Variable

Differential Transformer) or other transducer.The input amplitude may have dimensions of:

• Rotary acceleration, measured directly by a rotary accelerometer. derived from the output of a linear accelerometer and the radius from the center of the accelerometer to the center of the piston-rod, or

• Rotation, measured by an ADT (Angular Displacement Transducer)

Output Amplitude

For axial channels

For torsional channels

The amplitude measured on the output channel. The program may convert this amplitude to a dimension appropriate for the selected control channel (the control channel is selected on the Resonant Search Test Design window).The input amplitude has the dimension of linear acceleration, measured by an accelerometerThe input amplitude has the dimension of rotary acceleration, measured directly by a rotary accelerometer, or derived from the output of a linear accelerometer and the radius from the center of the accelerometer to the center of the piston-rod

Amplification The ratio of the output amplitude (from the output channel) to the input amplitude (from the input channel).

Aux Input 2 The amplitude measured on the auxiliary channel. This column appears if an auxiliary channel was selected on the Control Definition window. For a temperature channel, Set Point is reported and calculated by averaging the last 10 points.

Desired Phase This can be one of three things: the specified phase for a phase search, the phase at the maximum amplification for an amplification search, or the maximum phase for a maximum phase search.

Actual Phase The phase that was recorded during the test condition.Fatigue Cycles The number of cycles scheduled for each block.Completed Cycles The number of completed cycles indicates the number of cycles completed

after the amplitude tolerance, specified in the Control Definition window, was achieved.


Column Description

793.37 Resonance Search and Fatigue Elastomer Configure Program 81

Elastomer Configure ProgramThis section describes the Elastomer Configure program. Use the Elastomer Configure program to make global modifications to certain settings for the resonance search and fatigue processes:

Contents Open the Configure Dialog 82

Configure Window Settings 83


Open the Configure Dialog

Elastomer Configure Program82

Open the Configure DialogYou access the Configure dialog by running the cfg.exe executable and opening the 793.37 configuration file. This dialog provides a user interface to make registry changes that effect the global settings for the resonance search and fatigue processes. To open the Configure dialog:

1. From the Start menu, select Run

2. Enter cfg.exe and press OK

3. From the File menu select Open.

4. From the Open dialog, select cfg_37.prof and press Open.

5. The Configure dialog opens.

Configure Window Settings


Configure Window SettingsWhen you open a configuration file, you will see a window similar to the one shown below.

• The Profile Key explains what the currently highlighted configuration setting does.

• If you change the Current Value, select Save on the File menu to save your change.

• Configuration changes become effective when you enter the locked execution mode.

Max. APC AmplitudeControl Count

This option determines the maximum iteration attempts the Resonant Search will try before quitting when using APC amplitude control.

The number of maximum iteration attempts can be between 1 and 100 (inclusive). The default is 10.




Minimum High SpeedTicks

This option limits the maximum data acquisition rate Resonant Search will use when using high speed data acquisition. Depending on the resources in use on your system, high speed data at 49152 Hz might not be possible.

Enter the ratio corresponding with the desired frequency:

• 1 = 49152

• 2 = 24576

• 3 = 16384

• 4 = 12288

• 6 = 8192

The default entry is 2 (24576 Hz).

Max. IterativeAmplitude Control

Count

This option determines the maximum iteration attempts the Resonant Search will try before quitting when using iterative amplitude control.

The maximum number of iteration attempts can be between 1 and 100 (inclusive). The default value is 20

Span Divider This option controls the maximum amount of overprogramming that can occur when using the iterative amplitude control method. The desired amplitude is multiplied by this value and the segment generator span is divided by the value. The overprogramming limit is reached when the actual span value reaches 20000. For most systems, you should leave the span value to 2.

The divider value can be between 1 and 100 (inclusive). The default value is 2.

Min Iteration Fbk This option defines the ratio of minimum amplitude response when using iterative amplitude compensation. The amplitude compensator will not start compensating the command until the response is greater this pre-defined ratio. For example, if desired amplitude is 1.0 mm and the response is 0.4 mm, with this key set to 0.5 (or 50%). In this case, the ratio of the response to the desired amplitude is 0.4 (or 40%), which is less than the minimum requirement of 0.5 and thus the amplitude compensator will not compensate the command. This is a safe guard to protect your specimen in the case of servo valve not responding when test first starts.

The minimum amplitude response ratio can be between 0.0 and 1.0 (inclusive). The default value is 0.6.



Mean Iteration Gain This is used when performing mean/setpoint adjustments. The value is the percentage of mean error to be applied to the current setpoint value.

Allowable values for the gain are between 0.1 and 1.0 (inclusive). The default value is 0.8.

Mean IterationTolerance

This is the value used to determine if the mean level is out of tolerance.

Allowable values are between 0.0 and 1000.0 (inclusive). The default value is 0.1.

Span Profile Profile for span boost multipliers in the format “x1 y1 x2 y2 ... x10 y10” where:

x1 is the 1st frequency (in Hz)

y2 is the 1st span multiplier

x2 is the 2nd frequency (in Hz)

y2 is the 2nd span multiplier

etc.

Minimum value for the frequencies and multipliers is 0. Maximum value for the frequencies and multipliers is 1000. The default values are:

50 1 100 1 150 1 200 1 250 1 300 1 350 1 400 1 450 1 500 1

Amplification unitselection

Use this selection to determine the unit used for the amplification result. Input 0 for unitless. Input 1 for db. Formula for using db unit is:

20 * Log(output accel/input accel)

The default is 0, unitless.

Maximum plot datapoints for ResonanceFatigue run-time plot

windows

This option determines the maximum data points allowed in the Resonance Fatigue plot windows.

The maximum number of plot data points is between 1 and 10000 (inclusive). The default is 1000. See “Plot Data Decimation” on page 54 for additional information.




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793.37