Reply To: Calculating Cycle

[Daniel Shaw]

Are the data in the acceleration table multipliers on the applied acceleration in the FE model?  If so, why can’t you use a Time Series Load Mapper in Ansys nCode DesignLife? DesignLife time series load mapping uses one set of FE results and scale factors from a time history file to create time varying stress.  If you can convert your time base acceleration data to a PSD spectrum, you can run a DesignLife vibration fatigue analysis using that spectrum, but I do not see why it is necessary (or preferred).

Is the moment load constant or does it vary with time?  If it is a constant load, then the stress it produces does not directly contribute to the alternating stress.  It acts a mean stress.  The DesignLife time series load mapper has an option to specify a “static” result set.  The stresses from the static result set will not vary over time, but they will be used in any mean stress calculations.