Component Mode Synthesis

1. Vibration of a Clamped Beam (Craig-Bampton method)

The test computes vibration modes of a clamped beam with the Component Mode Synthesis method [33] global-local analysis method. The analysis consists of 2 steps, one with a global coarse mesh, and one with a local fine mesh. In a first step the global model is reduced to a macro-element. Then, the local model uses this reduced system defined by the global model for making a local (detailed) vibration analysis.

Clamped beam model.

Figure 89. Clamped beam model.


The global-local analysis is performed as follows:

  1. Condensate the global model (global.mdl)

  2. Create the input database of the local model (file detail.mdl).

  3. Update the input database of the local model with the information from the global model. This step has to be performed with a Python script (file b2ipupdate.py).

  4. Compute vibration modes with the local model.

Vibration modes. Dotted: Local model. Solid: Global reference model.

Figure 90. Vibration modes. Dotted: Local model. Solid: Global reference model.




[33] Also referred to as the Craig-Bampton method.