A Simple Example of Fatigue Life Estimation using Abaqus and Fe-Safe (cyclic load)

Description

This video explains fatigue life predictions of a component under cyclic loading using simulation in Abaqus and Fe-safe. At first, we give a brief explanation of common approaches to predict the components of fatigue life. Theories such as Goodman, Soderberg, etc. are among them. Then, a brief introduction to Fe-safe software is followed by an explanation of the design algorithm. Next, the model is shown in Abaqus environment. We then use the model results as an input for Fe-safe software to predict the fatigue life of the component under the cyclic load.

The table of contents:

0:00 Introduction

1:55 Explanation of cyclic loading

3:18 Explanation of the model

3:58 An introduction to Fe-safe

5:45 Creating the model in Abaqus

7:04 Creating the model in Fe-safe

9:54 Validating the Fe-safe results

11:14 Ending

If you are interested  you can find the YouTube link here:

To learn more about SRI1 please use the following link:
http://oss.jishulink.com/caenet/forums/upload/2014/09/25/191/45541828203375.pdf

Here you could download the files

Fe-safe:

This software was mainly developed to predict fatigue life in components. Using Abaqus outputs as input, it predicts fatigue life based on geometry, material, stress, etc.
Fe-safe was developed about 30 years ago and it is used for academic and industrial applications. Over the years, it has been updated many times. This software is unique for engineer because of its time-efficient and accurate processing. It is the first of its kind to be able to analyze multiaxial strain-based fatigue techniques. There are many applications for this software, such as thermo-mechanical fatigue, creep fatigue, and materials ranging from metals to rubber.

Model for Fatigue in Fe-safe:

Fatigue is an important parameter in designing components. This parameter evaluates the durability of the components under cyclic loading. Engineers develop models for Fatigue in Fe-safe software to estimate the number of cycles that the component can take. For this evaluation, you need to know the following background to understand fatigue life prediction in Fe-safe:

Gerber’s theory: The 2nd degree “Gerber’s theory” equation does not take the effects of negative “compressive stress” into account which is considered one of the major drawbacks of this theory.
Goodman’s theory: The next theory would be “Goodman’s” which uses “Ultimate stress” in its calculations. The high accuracy of this theory has made it very useful in industry.
Soderberg’s theory: “Soderberg’s theory” which is rather conservative compared to the others includes “yield stress”. However, this theory is rarely used.
Morrow’s theory: We have “Morrow’s theory” which uses “True Fracture stress” in its calculations.
The area underneath each of these diagrams indicates the “infinite life” of the material.

Types of loading:

There are different types of loading that we normally deal with in these types of problems.

1. The first one is the “fully reversed” loading. In this loading, the Stress Ratio, which is shown with the R symbol, is -1. Besides that, the “Mean stress” equals zero, since “Maximum” and “Minimum Stress” values are equal and opposite in direction their sum is zero. In other words, it is a reversible load.
2. The second type of loading we are going to discuss is the “Cyclic loading”. In this loading type, oscillations occur around the “mean stress” axis. As you can observe, Stress is always tensile and never equals zero.
3. The third loading type is “Pulsating loading” in which “mean stress” equals “amplitude stress” and “Stress ratio” equals zero. We have used this type in our simulation.

If you are looking to book an online tutorial or if you have any questions please send an email to:

samanhoseini@hyperlyceum.com