Hello,
In Optistruct frequency response modal analysis, I am getting very high stress peaks outside of the natural frequencies. For example, I am applying same amount of acceleration from 1 to 100 Hz. According to the modal analysis, system has natural frequencies at 11.4 , 14.0 , 16.7 , 27.08 Hz. But when I investigate stress vs. frequency, I obtain the highest stress values at 22.6 Hz with much higher than the ones at natural frequencies. What can be wrong here?
