Frequency and Transient Solutions with Mesh Glueing

Vibration Mode Shapes

To demonstrate the use of mesh glueing in frequency and mode superposition solutions, we consider the mechanical arm already analyzed in our January 15 News.

Recall that the arm was modeled using four parts glued together. Each part was meshed independently and the meshes are not compatible. The movies given above and at the right show the vibration modes corresponding to the lowest four (nonzero) frequencies. Note that the parts are firmly glued together with no spurious vibrations at the part interfaces.

The model was then subjected to an impulse pressure loading (see Figure below) and the response was obtained using direct time integration (the trapezoidal rule) and mode superposition using the four modes. The graphs below show that the two solutions are practically identical.

This example illustrates that frequency solutions and transient analyses (by direct time integration or mode superposition) can be obtained of models that contain parts individually meshed and glued together — which is clearly a powerful analysis feature.

Schematic

Displacement Magnitude at Point A