Hello everyone,

        I have a question. I am performing a random vibration analysis, and I applied a preload analysis step beforehand. I found that the frequencies of the model changed, but the RMS values of the stresses did not change much. I checked and the initial stress magnitude is 500 MPa. I would like to ask how the stress results of the random vibration analysis step can include the influence of the initial preload stress results. 

      Thank you.