The Introduction of Pro-EMFATIC For Femap · PDF fileThe Introduction of Pro-EMFATIC For Femap ... Like FEA, Durability analysis helps reduce time and cost for physical ... - Life

Unrestricted © Siemens AG 2014

FEMAP SYMPOSIUM 2014

Discover New Insights Femap Symposium 2014

May 14-16, Atlanta, GA, USA

The Introduction of

Pro-EMFATIC For Femap

Che-Wei L. Chang PhD

2014-05-15


Page 2 Siemens PLM Software © Pro-Lambda Solutions 2013. All Rights Reserved.

Table of Contents

•What Is Pro-EMFATIC？

•What Is Pro-EMFATIC For Femap？

•Why Use Pro-EMFATIC with FEA?

•Pro-EMFATIC Product Highlights

2014-05-15



What Is Pro-EMFATIC? - It calculates fatigue damage, life, and durability…

Pro-EMFATIC is a CAE software package that predicts fatigue life, fatigue

damage, and durability (a.k.a. fatigue safety factor) of mechanical

structures using “crack-initiation” life criterion equations.

Cyclic

Loading

Can it last for 10K duty Cycles?

How durable/safe is the structure?

How to gauge durability against the goal?

1.Overload: predicted by FE stress analysis

- FEMAP with NX Nastran

2.Fatigue: calculated using various life criteria

- Pro-EMFATIC

Common Material Failures:

How much fatigue damage accumulated?

Where are the critical fatigue locations?

2014-05-15



What is Pro-EMFATIC for Femap? - A fatigue solution embedded in Femap

Pro-EMFATIC works with Femap as an integrated module.

Taking the stress and/or strain results in FEMAP, Pro-

EMFATIC calculates the life, damage and safety factor of

mechanical structures and products.

The fatigue and durability results from Pro-EMFATIC can

be stored and displayed using the post-processing tools in

Femap. Femap

Pro-EMFATIC for Femap

Fatigue

Material

Life Criterion EQ. Fatigue

Evaluation

Kt, ms, md,

mt, mo

Loading definition with

cycles counting

Fatigue Loading Notch/

Surface/

Size/

Loading/…

influencing factors

Fatigue/Cyclic Properties

Life/Damage/Safety Factor

Stress/

Strain of FEA

2014-05-15



What is Pro-EMFATIC for Femap? - Working with both FEA results and Test measurements

Durability evaluations using both FEA and Test results:

Evaluations based on FEA results in Femap

Evaluations based on measured stress/strain histories and/or cyclic loads

Measured

s/e time

histories

Measured

s/e

2014-05-15



Why Use Pro-EMFATIC with FEA? - A complementary solution that extend the capability and value of FEA

Most of the mechanical structure is designed to endure repeated duty cycles (load

sequences). In each duty cycle, the loads (stresses) applied to the material may not be high

enough to cause any yield or rupture concern. However, the loading cycles may still cause

material fatigue and thus failure. Pro-EMFATIC for FEMAP is used to predict such failure and

assess the durability against the design goals.

Femap offers traditional FEA:

• Strength Analysis rates material‟s ability to resist failure (Yield/Rupture) due extreme loads

• Buckling Solvers calculate the loads causing structure instability

• Eigen and response analyses predict the resonance, beatings, and vibrations

• Durability rates material‟s ability to sustain failure due to repeated (cyclic) loading

Pro-EMFATIC for Femap Offers a complete set of fatigue and durability solutions

Like FEA, Durability analysis helps reduce time and cost for physical prototyping/testing

• Durability testing generally requires more time and resource than the other tests

2014-05-15



Pro-EMFATIC Product Highlights - Overall capabilities/features

•Predict life of mechanical products

•Evaluate damage of mechanical parts

•Assess durability (a.k.a. fatigue safety factors) against the designed goals

•Find the critical fatigue locations on mechanical parts

•Identify the most-damaging loading direction on structures

•Integrated solutions for Femap users

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Pro-EMFATIC Product Highlights - Fatigue Material Data Management

An XML-based material data system is used to create, edit, evaluate, select,

and manage material properties for various fatigue evaluations

Users can create fatigue material libraries and share them with colleagues

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Pro-EMFATIC provides 3 loading modes using existing FE results: — Duty Cycle

— Loading Path

— Superposition

Pro-EMFATIC Product Highlights - Fatigue Loading Definition

Superposition ^( ) ( )S SFm m

mt t

Loading

Scale Function

2014-05-15



• Pro-EMFATIC provides more than a dozen life criteria for fatigue evaluations and covers

most of the methods commonly used in the industry for high-, low-cycle fatigue evaluations.

Pro-EMFATIC Product Highlights - Stress/Strain Life Evaluation

Stress-Based Life

Strain-Based Life predict “life” and

cumulative fatigue

damage due to complex

loading conditions.

“How long will it last?”

“Where are the critical

fatigue locations?”

DS

N

Sm correction

zero-mean

W1＋W2＋…＋Wk＝W

Palmgren-Miner Rule

Modified-Miner Rule 1 1

1

W n

W N＝ 2 2

2

W n

W N ＝ k k

k

W n

W N＝

1

1k

i

i

i

n

N

• Pro-EMFATIC offers fatigue calculations for uni-axial, biaxial, and multi-axial loading, and users can

choose the corresponding life criterion accordingly.

Notch factor

Surface factor

Size factor

Load factor

High-Cycle Fatigue

Low-Cycle Fatigue

2014-05-15



BS7608 Standard：

B,C,D,E,F,F2,G,W,S,T 。

Weld Life

Pro-EMFATIC Product Highlights - Life Evaluation For Welds （1993 revision）

2014-05-15


Page 12 Siemens PLM Software

Event 1:Large-Scale temperature change during heating and cooling

# of Cycles: 2000

Pro-EMFATIC Product Highlights - Life Evaluation For Pressure Vessel （2010 revision）

Event 2:Incidental drop in

pressure

# of Cycles:350

Event3:Excessive waterflow

# of Cycles:300

Pro-EMFATIC ASME BPVC Life

Common fatigue loadings:

• Internal and external pressure

• Impact, including frequent pressure fluctuations

• Self weight and carried weight, including static and dynamic pressure from fluids

• Other parts, equipment, insulation, erosion/corrosion protective lining, piping, etc.

• Locally established loadings such as wind, snow, vibration, seismic movement

• Reactionary force from supporting rings, saddle, etc.

• Temperature fluctuations

2014-05-15



Pro-EMFATIC Product Highlights - Fatigue Safety Factor Evaluation

Safety Factor

“Can it last for the designed life-span?”

O

C

B A

M N Su

S-1

Sm

Sa

O

B

A

M N Su

S-1

Sm

Sa

“Where are the weak spots? critical

locations”

2014-05-15



Pro-EMFATIC Product Highlights - Rain-flow Counting

Rainflow Counting

)(tS

Different methods can be used to identify and count fatigue cycles from time histories of stress or strains.

Among them, the Rainflow counting method is the most widely accepted and commonly used counting

method. Using Rainflow counting, a time history is re-sequenced into various numbers of fatigue loading

cycles of stress (or strain) amplitudes with mean stresses. Once the loading cycles are identified and the

number of cycles counted, the fatigue damage of each cycle can be calculated and then linearly combined

into a cumulative damage for the whole loading history.

Pro-EMFATIC „s advanced Rainflow Counting method that

• Speeds up the counting for long histories by 3-5x.

• Counts both uniaxial and biaxial loading histories

2014-05-15



Pro-EMFATIC for FEMAP uses an advanced free-face transformation technology (for both

shell and solid elements) that greatly improves both accuracy and speed for large-size FE

fatigue evaluations.

1.transform FEA tensor results onto the tangent plan at the center of element free-faces

2.search for the effective loading directions and calculates the damages accordingly

Pro-EMFATIC Product Highlights - Transform FEA tensors for S-N (Scalar) evaluations

Scalar

Tensor

2014-05-15



Pro-EMFATIC Product Highlights - Searching for “max-damage” loading direction on element free faces

For non-proportional multi-axial loading, the principal loading axes change from time to time.

Pro-EMFATIC for FEMAP provides the max-damage-direction searching function, through

which the user can find the effective loading direction for fatigue evaluations.

Most-damaging loading direction w/ max fatigue damage

damage_1 damage_2 damage_3

θ

Δθ Δα

2014-05-15



Pro-EMFATIC Product Highlights - Performance

A. SMP for large models and long loading histories

B. “Free-Face” approach dramatically speeds up the fatigue evaluations

for “thick” solid-element models


FEMAP SYMPOSIUM 2014

Discover New Insights Femap Symposium 2014

May 14-16, Atlanta, GA, USA

Thank You

Documents

The Introduction of Pro-EMFATIC For Femap · PDF fileThe Introduction of Pro-EMFATIC For Femap ... Like FEA, Durability analysis helps reduce time and cost for physical ... - Life