SM1001 User Guidecste.sut.ac.th/miscste/company/manual/SM1001.pdfmanual accurate and up to date. However, if you find any errors, please let us know so we can rectify the problem

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SM100130 Nm Torsion Testing

Machine

User Guide

DB/bs/0913

TecQuipment Ltd User Guide

Contents

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Main Parts. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

The Base. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

The Gearbox (Strain Head) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

The Torque Measurement Head . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Other Parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Digital Meters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Optional Torsiometer (SM1001a). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Specimens . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

Versatile Data Acquisition System (VDAS®) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

Technical Details . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

Optional Torsiometer (SM1001A) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

Specimens . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

Noise Levels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

Theory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

Notation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

Modulus of Rigidity or Shear Modulus (G) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

Torsional Stress and Strain. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

Polar Moment of Inertia (J). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

Torque (T) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

Shear Stress (τ) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

Shear Strain (γ) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

Elasticity and Plasticity (or Elastic and Plastic Deformation). . . . . . . . . . . . . . . . . . . . . . . . . 15

Nominal and True Stress . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

Upper and Lower Yield Point - Normalised Low Carbon Steel . . . . . . . . . . . . . . . . . . . . . . . 16

The Bauschinger Effect. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

Setup Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

Safety. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

Useful Notes - Accuracy and the Optional Torsiometer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

Normal Set Up (all tests). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

To Fit the Optional Torsiometer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

TecQuipment Ltd User Guide

Tests. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

Test 1 - Shear Modulus (With Torsiometer) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

Aims . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

Results Analysis. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

Test 2 - Material Test (Without Torsiometer). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

Aim. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

Results Analysis. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

Further Tests - The Bauschinger Effect . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

Aim. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

Typical Results and Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

Test 1 - Shear Modulus (With Torsiometer) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

Test 2 - Material Test (Without Torsiometer) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

The Bauschinger Effect . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38

Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

Maintenance, Spare Parts and Customer Care . . . . . . . . . . . . . . . . . . . . . . . 41

Calibration Check. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

To Move the Gearbox . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42

Electrical . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43

Spare Parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44

Customer Care . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44

TecQuipment Ltd 1 User Guide

SM100130 Nm Torsion Testing Machine

User Guide

Introduction

Figure 1 The SM1001 30 Nm Torsion Testing Machine

Engineers need to know how different materials behave when stressed. They will then know how to use the right materials and material sizes for load-bearing structures and parts in their designs.

The Torsion Testing Machine (SM1001) is a laboratory-scale machine that easily fits on to a desk-top or bench and tests specimens of different types of metal. It shows the torque (stress) and twist (strain) in a specimen to find the yield strength and modulus of rigidity or ‘shear modulus’ for the metal. The machine can also test specimens to destruction to find their failure point.

TecQuipment supply one set of specimens with the machine. Extra optional sets are available from TecQuipment’s range of precision test specimens. TecQuipment also supply an optional Torsiometer (SM1001A) for accurate shear modulus results.

This machine is a useful companion to TecQuipment’s Universal Testing Machine (SM1000). The Universal Testing Machine tests the tensile strength of materials, which gives a similar pattern of results to the shear tests of the Torsion Testing Machine.

This product works with VDAS®

User Guide 2 TecQuipment Ltd

SM1001 30 Nm Torsion Testing Machine



Description

Figure 2 The 30 Nm Torsion Testing Machine

The 30 Nm Torsion Testing Machine is a compact machine, made of three main parts, and two separate electronic displays.

Specimens fit into hexagonal sockets, between the output of a Gearbox and the input of a Torque Measurement Head. The user turns the Hand Wheel of the Gearbox, which creates torsional stress at one end of the specimen. This end of the specimen moves (twists) through an angle. The Torque Head measures the torque at the opposite end of the specimen.

Main Parts

The Base

This is made of precision engineered sturdy box-section alloy with adjustable feet.

The Gearbox (Strain Head)

Manually turned, with a 60:1 reduction ratio and a sliding output shaft. A transducer measures the number of turns of the Gearbox. The Gearbox turns clockwise and anticlockwise to apply clockwise and anticlockwise torsion. The normal direction for tests is clockwise.

The output shaft of the Gearbox can slide in an axial direction, for three reasons:

• To allow easy fitting and removal of specimens.• To allow the specimen’s length to change without restriction during tests. If the specimen

was rigidly held in the axial direction, any test results would be incorrect.• To allow the use of slightly larger or smaller specimen lengths.

Torque Measurement HeadGearbox (Strain Head)

Base



The Torque Measurement Head

The Torque Measurement Head has a moment (torque) arm and industrial force sensor. Its torque value is a product of the length of the moment arm and the force on the force sensor.

Other Parts

The hexagonal sockets are removable, and TecQuipment supply two different sets: one set of metric (12 mm) sockets and one set of 3/16” Whitworth sockets. This allows for the slight variations in materials used for specimens. Try both sets of sockets on your specimen and use the sockets that fit best.

For safety, a removable clear guard covers the specimen area.

TecQuipment supply a calibration arm so that the user can check the accuracy of the Torque Measurement Head.

Digital Meters

Figure 3 The Digital Meters

The Digital Angle Meter (DA1) calculates and shows the angle of twist at the Gearbox end of the specimen. This meter automatically converts the amount of turns of the Gearbox output shaft into an angle in degrees.

A Clockwise Hand Wheel rotation gives a positive increase in specimen angle and positive torque.

An Anticlockwise Hand Wheel rotation gives a negative increase in specimen angle and negative torque.

The Digital Load Meter (DL1) calculates and shows the torque at the Torque Measurement Head. This meter automatically multiplies the known torque arm length by the force from a load cell force sensor. This meter has a ‘Peak Hold’ button, so that the meter will store the maximum reading of torque that it measures.

To activate the peak hold, press and hold the ‘Peak Hold’ button. Press the button again to deactivate the peak hold.

The Digital Angle Meter has two DC supply sockets, (one in and one out) so that you only need one DC power supply to work both meters.

Both electronic meters have sockets to connect to TecQuipment’s optional VDAS® for data acquisition.



Optional Torsiometer (SM1001a)

Figure 4 The Torsiometer (SM1001a) - Shown Mounted On Its Transit Bar

For increased accuracy of torsion measurement at small angles of twist (in the elastic region), TecQuipment can supply the optional Torsiometer (SM1001a). This is a precision instrument that fits to 6 mm diameter specimens to measure the angular displacement (twist) over a known ‘gauge length’ of 50 mm. It has a digital indicator that can connect to TecQuipment’s optional VDAS® for data acquisition (a connecting cable is supplied).

The digital indicator measures angular movement of the end of a small moment arm. It can display in units of inches and millimetres. The small moment arm is 1” (one inch) long, so that every 0.001” shows an angular movement of 0.001 radians.

0.001 in of displacement = 0.001 radian

The Torsiometer only works for small angles (radians), but this is good for measurements over the small angles of twist for the elastic region of the specimen materials.



Specimens

Figure 5 Recommended Dimensions of a Specimen

Included with the Torsion Testing Machine is a set of 6 specimens made of carbon steel. TecQuipment can supply a range of optional Torsion Specimens for use with the Torsion Testing Machine. There is a choice of different grade steels, or cast iron, or a copper/zinc alloy (brass).

Alternatively, the user may make their own specimens to the dimensions shown in Figure 5. The specimens may be made from 3/16” Whitworth or 12 mm metric hexagon bar. If you need to test longer specimens, you may re-adjust the position of the torque head and gearbox along the base.

WARNING

The drawing shows the recommended length of a test specimen. You can make longer test specimens and adjust the position of the torque head and gearbox along the base, but the guard may not be long enough to protect you when testing specimens to destruction.

CAUTIONThe TecQuipment specimens are the correct material and dimensions, so that the machine stress does not exceed 30 Nm (nominal). If you make your own specimens, make sure that you do not exceed 30 Nm in your tests.

143 mm

76.2 mm parallel

Nominal 6 mm diameter 0.445”/11.3 mm acrossflats (3/16” Whitworth)

or12 mm across flats



Versatile Data Acquisition System (VDAS®)

Figure 6 The VDAS® Hardware and Software

TecQuipment’s VDAS® is an optional extra for the Torsion Testing Machine. It is a two-part product (Hardware and Software) that will:

• automatically log data from your experiments

• automatically calculate data for you

• save you time

• reduce errors

• create charts and tables of your data

• export your data for processing in other software

NOTE You will need a suitable computer (not supplied) to use TecQuipment’s VDAS®.





Technical Details

Optional Torsiometer (SM1001A)

Main Part Dimensions: 1100 mm long x 400 mm depth x 350 mm height

Weight (without meters): 22 kg

Gearbox: 60:1 Ratio Sealed Gear and Worm Drive Unit

Torque Measurement Head: Maximum Torque 30 Nm

Operating Environment Indoor (laboratory)Altitude up to 2000 mTemperature range 5°C to 40°CMaximum relative humidity 80% for temperatures up to 31°C, decreasing linearly to 50% relative humidity at 40°COvervoltage category 2 (as specified in EN61010-1).Pollution degree 2 (as specified in EN61010-1).

Digital Load Meter (DL1)

Weight: 1.5 kgRange: Up to 30 NmLoad input socket: 5-pin DIN type, extra low voltage <25 VDCType RJ45 socket for VDAS, extra low voltage <25 VDCPower Input: 2.1 mm DC power socket 12 VDC centre positive

Digital Angle Meter (DA1)

Weight: 1.5 kgRange: Greater than 10000 degrees.Angle input socket: 6-pin DIN type, extra low voltage <25 VDCType RJ45 socket for VDAS, extra low voltage <25 VDCPower Input and output: 2.1 mm DC power sockets 12 VDC centre positive

Power Supply Input: 90 VAC to 264 VAC 50 Hz to 60 Hz at 1 AOutput: 12 VDC at 5 A centre positive

Fuse Not user replaceable

Dimensions 130 mm high x 100 mm wide x 70 mm depth

Weight 500 g

Gauge length (Test length) 50 mm

Specimen clamp diameter Nominal 6 mm

Display Units Millimetres or Inches0.001 inch = 0.001 radians



Specimens

Noise Levels

Less than 70 dB(A)

TR1010 - Code MT15 (Supplied with the equipment)0.15% Carbon Steel (as drawn)

Shear Modulus: 79 GPaDimensions as shown in Figure 5.

TR1011 - Code MT15N (Optional)0.15% Carbon Steel (normalised at 900°C)

TR1020 - Code MT40 (Optional)0.4% Carbon Steel (as drawn)

TR1021 - Code MT40N (Optional)0.4% Carbon Steel (normalised at 860°C)

TR1040 - Code MTX (Optional)CZ121 Brass (60% Copper, 40% Zinc)


TR1050 - Code MTCI (Optional)Grade 180 Cast Iron




Installation

The Torsion Testing Machine is supplied already assembled.

The base and the digital meters need a space of 1100 mm x 700 mm. If you are to use the optional VDAS®, allow room for the VDAS® hardware and a suitable computer.

1. Use assistance to hold the base of the machine and put it onto a sturdy, level, workbench or desktop.

2. Connect the cables of the equipment as shown in Figure 7.

Figure 7 Connection

3. Use the cable supplied with the power supply to connect it to a suitable mains electrical supply.

These are the colours of each individual conductor:

WARNING

Connect the apparatus to the supply through a plug and socket. The apparatus must be connected to earth.

The plug and socket supply connection to the power supply is the main method of electrical isolation.

Make sure you do not block access to this connector.

To mainselectrical supply

Force SensorLoad Cell

GearboxTransducer

Digital Angle Meter Digital Load Meter Optional VDAS Hardware

DC SupplyLink

DIGITALINPUTS

POWER COMMSRS232

OR

HUB BOARD

DIGITALOUTPUT

DTI INPUT BOARD

1

2

3

4

DIGITALOUTPUT

ANALOGUE INPUT BOARD

INPUT SOCKET 1

INPUT SOCKET 2

VERSATILE DATA ACQUISITION SYSTEM

12V

Mains to low voltagepower supply

ORIGIN ON/OFF

in/mm +/-

Digital Indicator (of Optional Torsiometer)

GREEN AND YELLOW: EARTH E OR

BROWN: LIVE

BLUE: NEUTRAL





Theory

This section gives only the basic theory needed for the experiments in this guide.

Notation

Modulus of Rigidity or Shear Modulus (G)

The Shear Modulus or Modulus of Rigidity is a measure of the rigidity of the material when in ‘shear’ - when it is twisting. It is a ratio of the shear stress and the shear strain of the material:

(1)

Symbol Description Units

A Area m2

M Applied moment Nm

F Force N

L Total Length of a specimen m

l Test Length m

T Torque Nm

J Polar Moment of Inertia m4

G Shear Modulus Nm-2

D Diameter of specimen m

r Radius of specimen m

τ Shear Stress Nm-2

γ Shear Strain

θ Angle of twist Radians

NOTE This formula only works when the material is stressed in its elastic region.

G Shear StressShear Strain------------------------------- F A⁄

Δx h⁄------------- τ

γ--= = =



Torsional Stress and Strain

Polar Moment of Inertia (J)

This is an equation that shows the ability of a circular cross-section beam or specimen to resist torsion (twisting). A higher polar moment of inertia shows that the beam or specimen can resist a higher torsion or twisting force. The diameter of the beam determines polar moment of inertia. A larger diameter gives a larger polar moment of inertia.

(2)

The general equation for the torque in a circular cross-section beam or specimen is:

(3)

Torque (T)

Figure 8 Torque (Twisting Force)

The twisting force (torque) at the end of a specimen is the moment of force on the torque arm:

(4)

NOTE The Digital Load Meter (DL1) already calculates the torque for you. It is already programmed with the length of the torque arm.

J πD4

32----------=

TJ--- Gθ

l-------=

Force ( )F

Torque Arm

Angle of twist ( )�

Diameterof specimen ( )Dl

Known test length

T F Torque Arm Length (m)×=



Shear Stress (τ)

The theoretical shear stress for a solid circular bar is

(5)

Shear Strain (γ)

The theoretical shear strain for the solid circular bar is

(6)

A rearrangement of the Shear Modulus therefore gives:

(7)

Elasticity and Plasticity (or Elastic and Plastic Deformation)

Figure 9 Stress/Strain Curves

A material is perfectly elastic if it can be compressed or stretched (deformed) by any amount, and then return to its original shape when the stress is removed. Its atoms have not moved, but the bonds between them have stretched, then returned to their original position.

A material is plastic if it can be compressed or stretched (deformed) by a small amount, and then not return to its original shape when the stress is removed. Its atoms have actually moved and will not return.

Most materials have both elastic and plastic properties. When stressed by a small amount, they behave like an elastic material, up to their elastic limit or yield point. When stressed by a large amount (that takes them past their elastic limit), they behave like a plastic material. Rubber and flexible materials usually have more elasticity than more brittle materials like metal or ceramics.

τ TD2J--------=

γ τG---- rθ

l-----= =

G TD( ) 2J( )⁄rθ( ) l⁄

---------------------------=

Stress

Strain

Perfectlyelasticmaterial

Common Materials

ElasticRegion

PlasticRegion

Yield Point

Stress

Strain

Brittle Fracture

ElasticRegion

PlasticRegion

Yield Point

Ductile Fracture

X

X



Nominal and True Stress

The maximum shear stress (τmax) in torsion occurs at the surface of the material in torsion, and we know that the material diameter determines the maximum stress.

However, as a specimen is stressed, its diameter actually becomes smaller, so its stress level is actually higher than predicted and is a ‘nominal stress’. This effect is hardly noticeable when the specimen is in its elastic region, but increases as the specimen moves through its plastic region. However, it is acceptable to assume a nominal stress during normal tests.

Upper and Lower Yield Point - Normalised Low Carbon Steel

Figure 10 Upper and Lower Yield Strength

Normally, materials have a yield point, at the limit of their elastic region. Normalised mild steel (low carbon content) has an upper and lower yield strength.

Figure 10 shows this. The specimen yields at point A and the stress immediately falls to a lower value, point B. The stress and strain curve then follows a similar shape to other materials.

A

B

To

rqu

e(s

tre

ss

)

Angle of twist (Strain)

Upper yield

Lower yield



The Bauschinger Effect

When a metal bar in torsion is overstrained and the load is removed, the load-free bar is full of residual stresses. These stresses are of two kinds:

1. Body stresses - that affect a relatively large volume of metal (for example - macro stresses)

2. Textural stresses - that are really the residual stresses in between and within the crystals of the metal, caused by deformation of each crystal (they are in the actual texture of the metal)

Body stresses (which are beneficial) are more stable than textural stresses (which are harmful). A low temperature heat treatment of 200°C will remove textural stresses in steel.

Figure 11 Reverse torsion tests

To show the residual stresses, the Torsion Testing Machine can do reverse torsion tests, as shown in Figure 11. In the initial load cycle the specimen yields at A, is deformed (plastic region) to B, then unloaded and plastically deformed in the reverse direction, to point C. The specimen is then loaded in the positive direction to point D, unloaded and given a low temperature heat treatment, and then reloaded. It now yields at E rather than D. Thus the harmful effects of the textural stresses, which were removed by the heat treatment, were equal to the increase from D to E.

If the material is now strained to point F and then strained in the reverse direction, to point G (slight negative plastic strain). On reloading it arrives back at the strain represented by point H.

This shift of the strength range in the direction of the plastic deformation is sometimes called the ‘Bauschinger Effect’.

To

rqu

e

Angle of twist

A

E F

G

C

D

B

H





Setup Information

Safety

Useful Notes - Accuracy and the Optional Torsiometer

The normal angle measurement of the SM1001 uses the overall movement of the Gearbox input shaft. This overall movement includes the twist of the specimen, but also the mechanical movement of:

• The whole machine• The Gearbox output shaft• Any twist in the sockets• Angular twist of the torque measurement head

All these parts are very stiff and the errors are small, so your results for the material tests (over a large angle) will be accurate. However, when you test the specimen in the elastic region (over a small angle), the errors will give poor accuracy. To avoid these errors, the Torsiometer measures the strain over a known, uniform length (gauge length) of the specimen. The range of the Torsiometer is small and it is sensitive, so you must remove it before the specimen reaches its yield point.

Normal Set Up (all tests)

1. Accurately measure and record the dimensions of your specimen.

2. Check the distance across the flats at the ends of your specimen, then choose the correct sockets to fit your specimen (12 mm or 3/16” Whitworth).

3. Fit the sockets to the torque head and the gearbox output, as shown in Figure 12.

WARNING Wear eye protection when using or working near to this apparatus.

WARNING

Before you remove a specimen, reduce the torque (stress) back to zero.

If you do not use the equipment as described in these instructions, its protective parts may not work correctly.

WARNING When testing to destruction, always fit the guard.



Figure 12 Fit the sockets to the Torque Head and the Gearbox Output

4. If necessary, fit the optional Torsiometer to the specimen as shown in ‘To Fit the Optional Torsiometer’.

5. Fit the specimen (with Torsiometer if fitted) to the sockets. Slide the gearbox output shaft along so that the specimens ends fit fully into each socket.

Figure 13 Fit the Specimen

6. Switch on both Digital Meters, and press their ‘Press to zero’ buttons.

7. Fit the clear guard around the specimen.

8. To remove any mechanical error (or ‘backlash’), slowly turn the Gearbox Hand Wheel until the load display starts to show a small value of torque, then use the ‘Press to zero’ buttons to set all displays to zero.

9. If you are to use the Torsiometer, carefully press its button that sets its display to zero.

NOTE You cannot fit the guard when you use the Torsiometer.



To Fit the Optional Torsiometer

You must fit the Torsiometer to the specimen before you fit the specimen into the Torsion Machine.

TecQuipment package the Torsiometer in two parts: The Digital Indicator and the Mechanism. The Mechanism is supplied fitted to a Transit Bar.

Figure 14 TecQuipment Package the Torsiometer in Two Parts

1. Fit the battery to the Digital Indicator as described in its user instructions.

Figure 15 Loosen the Hexagon Fixings

2. Use a hexagon tool (supplied) to loosen the hexagon fixings and remove the Transit Bar (see Figure 15).

3. Slide the Specimen into the Gauge.

4. Push the gauge together so that it grips the specimen at exactly 50 mm gauge length.

5. Tighten the fixings. They must hold the specimen securely, but not so tight that they damage the specimen.

Digital Indicator

Locking Ring

Measurement Arm Transit Bar



Figure 16 Slide the Specimen into the Gauge

Figure 17 Check that the Gauge is Pushed together to give a gauge length of 50 mm.

6. Push the Digital Indicator into its holder and gently tighten the thumbscrew.

7. Set the distance from the holder to the measurement arm as approximately 3 mm and tighten the large locking ring.

8. Now fit the Specimen to the Torsion Machine.

9. If you need to use the Torsiometer with VDAS®, remove the plastic ‘bung’ at the top of the Indicator and use the special cable (supplied) to connect to VDAS®, as shown in Installation on page 11.

10. Switch on the Digital Indicator and set its display to zero as shown in its user instructions.

50 mm



Figure 18 Fit the Digital Indicator fully into its Holder and Gently Tighten the Thumbscrew

Figure 19 Set the Gap to Approximately 3 mm and Tighten the Locking Ring





Tests

Test 1 - Shear Modulus (With Torsiometer)

Aims

To find the shear modulus for the specimen material and compare it with given values.

To familiarize students with the equipment and its sensitivity in the specimen’s elastic region.

Procedure

1. Set up the apparatus as shown in ‘Normal Set Up (all tests)’.

2. Fit the Torsiometer as described in To Fit the Optional Torsiometer on page 21.

3. Create a table of results similar to Table 1. If you use VDAS®, the software will do this for you automatically.

Table 1 Blank Results Table

4. In this test, you will only stress the specimen in its elastic region, so you must increase the angle of twist in 0.005 radian steps up to a maximum of 0.030 radians. Record the torque at each step. If you are to use VDAS®, press the ‘record data’ button at each step.

Specimen Material:Specimen Dimensions:Polar Moment of Inertia:

Angular Displacement

(0.001”)(Radians) Torque (Nm) Stress Strain

0 0 0 0

0.005

0.010

0.015

0.020

0.025

0.030

CAUTIONDo not exceed 0.030 radians for the TecQuipment specimens. You will stress them past their elastic limit.



Results Analysis

Use equation 2 to find the polar moment of inertia for your specimen.*

Use Equations 5 and 6 to find the shear stress and strain for each set of results and complete your table.

Plot a chart of stress (vertical axis) against strain (horizontal axis).*

Find the gradient of your chart. The value will the shear modulus (G) for your specimen.*

* If you use VDAS®, the software will automatically calculate these for you.

Compare your value of G for your specimen material with the value given in Technical Details on page 9.

NOTE

For best results, turn the hand wheel at a constant rate in one direction only. If you turn it backwards by even a small amount, your results for the test will be wrong.



Test 2 - Material Test (Without Torsiometer)

Aim

To find the mechanical properties of the test material.

Procedure

1. Set up the apparatus as shown in ‘Normal Set Up (all tests)’.

2. Create a table of results similar to Table 2. If you use VDAS®, the software will do this for you automatically.

Table 2 Blank Results Table

WARNING This test takes the specimens to destruction. Fit the guard.

Specimen Material:Specimen Dimensions:

Angle (degrees) Torque (Nm) Angle (degrees) Torque (Nm)

1

2

3

4

5

6

7

8

9

10



3. Press the ‘Peak Hold’ button of the Load Meter so that it records the maximum torque in the test. If you are to use VDAS®, the software records the Peak Torque value and the normal torque value.

4. For the first part of the test the specimen will be stressed in its elastic region, so you must increase the angle of twist in small steps of 1 degree.

5. At each angle, record the angle and the torque value. If you are to use VDAS®, press the ‘record data’ button at each step.

6. After approximately 10 degrees, the specimen has passed its upper yield point. You can now increase the angle size between measurements to larger increments.

7. You may now continue to increase the angle until the specimen breaks.

8. Repeat the test on specimens of different material.

Results Analysis

Plot a chart of torque (vertical axis) against angle of twist in degrees (horizontal axis).*

On your chart, mark the yield point (upper and lower yield point for some steel specimens).

Use equation 2 to find the polar moment of inertia for your specimen.*

Use equation 5 to find the shear stress* at the yield point.

Compare the results for each type of specimen material.

* If you use VDAS®, the software will automatically calculate these for you.

If you have the brass specimen, measure its final length and diameter to show the effects of torsional stress. What can you state about the ‘nominal stress’ assumption?

If you have all the optional specimens:

• Which materials give the highest torque, and corresponding stress levels?

• Which materials fracture quickest (need the least turns of the gearbox)?

NOTE

For best results, turn the hand wheel at a constant rate in one direction only. If you turn it backwards by even a small amount, your results for the test will be wrong.



Further Tests - The Bauschinger Effect

Aim

To prove the Bauschinger Effect.

Procedure

1. Set up the apparatus as shown in ‘Normal Set Up (all tests)’. Do not fit the Torsiometer. Fit the guard in case of accidental material fracture.

2. Create a two tables of results similar to Tables 3 and 4. If you use VDAS®, the software will do this for you automatically.

3. Turn the gearbox Hand Wheel clockwise for the first part of the test, and record the torque and angle, at every 2 degree while the specimen is in its elastic region, then at larger intervals as it enters its plastic region, up to 100 degrees. Note the maximum positive torque value.

4. Now turn the Gearbox Hand Wheel anticlockwise and record the torque at 2 degree angles until the negative torque value is similar to the maximum positive torque value. Note the maximum negative angle of twist and maximum negative torque value.

5. Turn the Gearbox Hand Wheel clockwise again until you reach 100 degrees. Note the increase in torque for the same angle.

6. Turn the Gearbox Hand Wheel back to remove the stress and remove the specimen for heat treatment (at 200°C).

7. When the specimen has cooled, refit it to the Torsion Machine and repeat the test. Note that the maximum torque values are now greater.

NOTE Only use normalised low carbon steel specimens for this test.



Table 3 Blank Results Table - Part 1

Table 4 Blank Results Table - Part 2

Specimen Material:Specimen Dimensions:





Typical Results and Conclusions

These results are typical only, actual results may be slightly different

Test 1 - Shear Modulus (With Torsiometer)

Figure 20 Modulus Test with 0.15% Carbon Steel (as Drawn) Specimen

Figure 21 Modulus Test with 0.15% Carbon Steel (Normalised) Specimen

Modulus Test - TR1010 0.15% Carbon Steel as drawn

0

20

40

60

80

100

120

140

160

0 0.0005 0.001 0.0015 0.002

Strain

Str

ess

(MN

.m-2

)

Gradient = 83 GPa

Modulus Test - TR1011 0.15% Carbon Steel Normalised

0

20

40

60

80

100

120

140

160

0 0.0005 0.001 0.0015 0.002

Strain

Str

ess

(MN

.m-2

)

Gradient = 76 GPa



Figure 22 Modulus Test with 0.4% Carbon Steel (As Drawn) Specimen

Figure 23 Modulus Test with 0.4% Carbon Steel (Normalised) Specimen

Modulus Test - TR1020 0.4% Carbon Steel As Drawn

0

20

40

60

80

100

120

140

160

0 0.0005 0.001 0.0015 0.002

Strain

Str

ess

(MN

.m-2

)

Gradient = 76 GPa

Modulus Test - TR1021 - 0.4% Carbon Steel Normalised

0

20

40

60

80

100

120

140

160

0 0.0005 0.001 0.0015 0.002

Strain

Str

ess

(MN

.m-2

)

Gradient = 79 GPa



Figure 24 Modulus Test with Brass Specimen

Figure 25 Modulus Test with Cast Iron Specimen

Modulus Test - TR1040 Brass

0

10

20

30

40

50

60

70

80

90

0 0.0005 0.001 0.0015 0.002

Strain

Str

ess

(MN

.m-2

)

Gradient = 44 GPa

TR1050 Cast Iron - Modulus Test

0

10

20

3040

50

60

70

80

0 0.0005 0.001 0.0015 0.002

Strain

Str

ess

(MN

.m-2

)

Gradient = 39 GPa



Test 2 - Material Test (Without Torsiometer)

Figure 26 Material Test with 0.15% Carbon Steel (as Drawn) Specimen

Material Test - TR1010 0.15% Carbon Steel as Drawn

0

5

10

15

20

25

0 50 100 150 200 250

Angle (Degrees)

To

rqu

e (N

m)

Fracture



Figure 27 Material Test with 0.15% Carbon Steel (Normalised) Specimen

TR1011 0.15% Carbon Steel Normalised - Material test

0

5

10

15

20

25

0 500 1000 1500 2000 2500 3000 3500

Angle (degrees)

To

rqu

e (N

m)

0

2

4

6

8

10

12

14

0 50 100 150 200

Angle (degrees)

To

rqu

e (N

m)

Fracture



Figure 28 Material Test with 0.4% Carbon Steel (As Drawn) Specimen

Figure 29 Material Test with 0.4% Carbon Steel (Normalised) Specimen

TR1020 0.4% Carbon Steel As Drawn - Material Test

0

5

10

15

20

25

30

35

0 200 400 600 800 1000 1200

Angle (Degrees)

To

rqu

e (N

m)

Fracture

Material Test - TR1021 - 0.4% Carbon Steel - Normalised

0

5

10

15

20

25

30

35

0 500 1000 1500 2000 2500Angle (Degrees)

To

rqu

e (N

m) Fracture



Figure 30 Material Test with Brass Specimen

Figure 31 Material Test with Cast Iron Specimen

TR1040 Brass - Material Test

0

2

4

6

8

10

12

14

16

18

0 1000 2000 3000 4000 5000

Angle (Degrees)

To

rsio

n (

Nm

)

Fracture

TR1050 Cast Iron - Material Test

0

5

10

15

20

25

30

0 50 100 150 200 250 300 350

Angle (Degrees)

To

rsio

n (

Nm

)

Fracture



The Bauschinger Effect

Figure 32 Bauschinger Effect - Part 1

Figure 33 Bauschinger Effect - Part 2

To

rqu

e(N

m)

10

10

20 40 60 80 100

Twist (Degrees)

0

0

To

rqu

e(N

m)

10

10

20 40 60 80 100

Twist (Degrees)

0

0



Conclusions

Figures 20 to 31 show typical results for the TecQuipment specimens available for use with the Torsion Testing Machine.

The gradients (shear modulus) for the steel and cast iron specimens are similar to the given values (within 5%). The gradient for the brass specimen is within 10% of the given values.

The normalised low carbon steel results (Figure 27) show its two yield points, the upper yield at approximately 9.6 Nm torque (223 MN.m-2 stress) and the lower yield at 7.7 Nm torque (180 MN.m-2 stress).

The normalised steel specimens need many more turns before they break (fracture) than the ‘as drawn’ steel specimens, and the cast iron specimens. However, the ‘as drawn’ specimens need a much higher torque than the normalised steels to stress them past their yield point. They also continue to give slightly higher torque levels in the plastic region than the normalised steel.

The cast iron and the high carbon steels give the highest torque (near to the machine’s maximum rating) of all the specimens. This is a maximum shear stress of approximately 700 GPa for a specimen with the nominal 6 mm diameter.

The Brass specimen shows a similar shear modulus to the steel specimens, a similar yield point to the normalised high carbon steel, and needs many more turns to fracture than any of the other specimens.

The dimensions of the steel and cast iron specimens may change through the material test, but only by a very small amount (less than 0.05 mm in diameter and less than 1 mm in length). The dimensions of the brass specimen visibly change through the material test. The diameter reduced from 6.03 mm to 5.8 mm. Its length increased from 143 mm to 149 mm. This shows that the ‘nominal stress’ assumption can give good accuracy for some materials and specimen dimensions, but not all.

Figure 32 shows the forward and reverse test on a low carbon steel specimen. Figure 33 shows the same test after heat treatment of the specimen at 200°C. The torque levels are now much higher. The curves have a flat area as they cross the zero torque line. The mechanical ‘free play’ of the gearbox, sockets and torque arm cause this.





Maintenance, Spare Parts and Customer Care

After use, store the machine in a dry and dust-free area, suitably covered.

To clean the apparatus, wipe clean with a damp cloth - do not use abrasive cleaners.

Regularly check all fixings and fastenings for tightness, adjust where necessary.

Calibration Check

Figure 34 Put the Calibration Bar into the Hole at the End of the Torque Measurement Head

If you believe that the load calibration is not correct, you may check it. To do this:

1. From the operators side, fit the end of the calibration bar into the end of the torque measurement head. There is a small rebate in the bar that will click into place.

2. On the Digital Load Meter, press and hold the ‘Press and hold to zero’ button. This will cancel out the mass of the calibration arm.

3. Apply a mass of exactly 6 kg to the end of the calibration arm. The display should show 29.43 Nm (+/- 0.1 Nm). Contact TecQuipment if the value is out of this range.

NOTE Renew faulty or damaged parts with an equivalent item of the same type or rating.



To Move the Gearbox

You may need to move the Gearbox if you need to test longer specimens. To do this,

1. Loosen the fixings that hold the Gearbox down to the base.

2. Carefully slide the Gearbox along the base.

3. Use a set square to check accurate alignment of the Gearbox against the base, then retighten the fixings.

Figure 35 Use a Set Square to Check Alignment of the Gearbox Against the Base.

WARNINGYou can make longer test specimens and adjust the position of the torque head and gearbox along the base, but the guard may not be long enough to protect you when testing specimens to destruction.



Electrical

You cannot repair the power supply for the Digital Meters. If it is faulty, replace it with a new and identical power supply.

Fuse Location

There are no user replaceable fuses on this equipment.

WARNINGDo not open the power supply.

NOTERenew or replace faulty or damaged parts or detachable cables with an equivalent item of the same type or rating.



Spare Parts

Check the Packing Contents List to see what spare parts we send with the apparatus.

If you need technical help or spares, please contact your local TecQuipment agent, or contact TecQuipment direct.

When you ask for spares, please tell us:

• Your name

• The full name and address of your college, company or institution

• Your email address

• The TecQuipment product name and product reference

• The TecQuipment part number (if you know it)

• The serial number

• The year it was bought (if you know it)

Please give us as much detail as possible about the parts you need and check the details carefully before you contact us.

If the product is out of warranty, TecQuipment will let you know the price of the spare parts.

Customer Care

We hope you like our products and manuals. If you have any questions, please contact our Customer Care department:

Telephone: +44 115 954 0155

Fax: +44 115 973 1520

Email: [email protected]

For information about all TecQuipment products visit:

www.tecquipment.com

http://www.tq.com

Documents

SM1001 User Guidecste.sut.ac.th/miscste/company/manual/SM1001.pdfmanual accurate and up to date. However, if you find any errors, please let us know so we can rectify the problem