Fatigue Advisor is a tool that lets you determine the fatigue life of your model. Fatigue Advisor is designed so novice fatigue users can get quick feedback on whether a design is sensitive to fatigue without having to provide all the input normally required. Fatigue Advisor does this by asking for input that is fairly easy to obtain and by internally setting very conservative defaults for input that you do not directly provide—cyclic material properties, for example. If you are an advanced fatigue user, you may want to alter these defaults to examine less conservative scenarios.

In its default state, Fatigue Advisor is an excellent tool for quickly identifying whether fatigue is an issue for your model, comparing design iterations, and identifying potential failure locations. Because the results that Fatigue Advisor provides are conservative, you can be confident that the tool will find any areas of concern in your model. For example, Fatigue Advisor uses a default value of 90% for material confidence level, meaning that 90% of the test results under the modeling conditions you set would have longer lives than the software predicts.

If you are a fatigue expert, you may not want to use Fatigue Advisor's internal defaults for some applications, specifically because these defaults are highly conservative. For instance, if you are primarily interested in comparing Fatigue Advisor's life predictions to specific test results or results provided by alternative fatigue simulation software, the conservative defaults may not provide good results correlation. In this case, you should consider adjusting the internal parameter defaults to ensure that you are comparing similar paradigms and to improve results correlation.

You change Fatigue Advisor parameter default settings through a variety of configuration options. Be aware that improper default settings can result in questionable analysis results. Thus, you should consider a thorough knowledge of fatigue theory to be a prerequisite for changing the defaults.

Here is a list of parameters whose defaults you can alter:

Another parameter that you may want to adjust is variable amplitude load history. Fatigue Advisor enables you to specify either a constant or variable amplitude load history when you define your fatigue analysis. If you decide to use a variable amplitude load history, you can either enter the data or import an ASCII file defining the load history. Importing a variable load history file can allow you to better correlate test results. Note that you do not need to change any configuration option default settings to utilize an ASCII file as the variable amplitude load history.

Return to Fatigue Analysis Overview.