Fatigue due to Dynamic
Vibration:


Special features:

Output:


Comments:

Click images...

Perform a modal frequency and mode shape analysis on a piece of rotating machinery to determine ways of eliminating a vibration, which is damaging equipment.

3D model setup with bricks, shells, and beams.

Resonant frequencies, mode shapes, and displacements.

This model was rather large, but solved in just over an hour for 15 modes. Click on the thumbnails above to expand the screen shots for better viewing. The 1st figure shows the FEA model with the FEA mesh turned OFF. The 2nd figure shows the model constraints. Setting up the shaft constraints to eliminate rigid body modes, which the solver doesn't like, and still allow it to pivot at the bearings and motor coupling, was tricky. The 3rd figure is a close-up showing some details of the shaft and bearings, etc. The last thumbnail will bring up an animation of the problematic mode. This result verified a known mode. The astute reader will not only be able to determine how this mode is excited, but also how to fix the problem. Three ways to fix this problem were suggested. Don't suggest shortening the shaft; it had to pass through a wall.