What is behind the "Durability Fatigue Analysis"?

Community Manager Community Manager
Community Manager

Q: What is behind  the "Durability Fatigue Analysis"?


A: Durability Fatigue Analysis is all about understanding the structural performance under cyclic loading.


Siemens has two main solutions :

1) A virtual, CAE approach - LMS Virtual.Lab Durability

2) A physical, test/measurement approach - LMS Tecware Fatigue Life Analysis


The Durability/Fatigue performance is governed by 3 things:


1) Material - determines the stress-life (Wöhler) or strain-life curve characteristics (a curve of the number of cycles to failure). Choose a material that is fatigue resistant. This is often balanced against the cost, weight and manufacturability of the material.


2) Geometry - determines how stress is formed. External load applied is transformed to high stresses due to geometry often referred to as "notches" or "stress risers". Use thicker cross sections and nicely rounded curvatures to reduce the stress and "manage" the load.


3) Loads - the only thing you can't completely control! Knowing how your part is loaded and which loads are fatigue relevant is important. Sometimes high loads are important. Sometimes low loads with many cycles are important. Both LMS Virtual.Lab and LMS Tecware have dedicated methods for analyzing the loads and determining which ones are important - sort of like putting a pair of fatigue goggles on to see what's important.


Any one of these or a combination of these can cause a Durability/Fatigue performance issue.


Moreover, the durability analysis is fully integrated into the wind turbine application LMS Samtech Samcef Wind Turbines.


That means that after setting up a template fatigue analysis for a selected component all wind load cases defined in LMS Samcef Wind Turbines will automatically run through a fatigue analysis. Standard results (e.g. min fatigue life per wind event)  3D plot (e.g. fatigue life) are automatically generated and may be directly viewed.


For the most damaging wind events you can open the fatigue tool LMS Virtual.Lab Durability directly and do dedicated fatigue post processing like seeing which of the loads and/or which parts of the wind history are most damaging.


Making the analysis more realistic & giving the engineer the tools to understand and improve his/her components is one of our main goals.