6.6. Using Component Mode Synthesis in the Multibody Analysis

CMS a Powerful Tool

Using CMS for static and transient nonlinear analysis reduces problem size and minimizes CPU-resource requirements. You can convert parts of a model which exhibit linear behavior (such as Rod2 in this case) to a superelement using CMS with large rotation. You can restrict all geometric, contact, and material nonlinearity to those parts of the model which require nonlinear behavior.

For more information, see Using Component Mode Synthesis Superelements in a Multibody Analysis and Component Mode Synthesis in the Substructuring Analysis Guide.

Using the flexible body created previously, create a component mode synthesis (CMS) model with large rotation. Using CMS for the multibody analysis consists of:

  1. Creating a superelement of the flexible body (generation pass).

  2. Using the superelement in the transient analysis (use pass).

  3. Recovering stress and displacement results for the entire model (expansion pass).

The results are similar to those of the flexible model, as shown:

To leverage the advantage of a CMS analysis for large rotation, define another part of the model, Rod1, as a flexible body. Define the other flexible part, Rod2, as a CMS part. The input fileCrankSlot_FlexibleCMS.inp is used to perform the CMS portion of the analysis.

The CMS part Rod2 assumes linear behavior with large rotations, whereas the flexible part Rod1 retains all geometric and material nonlinearity in the model, as shown: