Deformation Unmasked: Filtering Rigid Motions

Crash simulations are typically done with some initial velocity. A full vehicle meshed structure moves towards a barriere and the parts subsequently deform according to their mechanical properties. A typical deformation pattern for a front crash may look like this

A typical analysis may be to find a part with largest deformation, but its all superimposed by the rigid body motion. The first approach is typically to select some reference, e.g. by three points on a undeformed part like the roof.

This method still contains rigid motions on the wheels. Some statistics on the parts would be distorted by the large values of the wheels and the selection also depends on the selection of the undeformed area (see Displacement and Rigid Body Movement).

The wheels might be removed from the evaluation but for an automation, they must be labeled and labels may change over time or adapted by user. Moreover, the wheels might be part of the analysis.

So, how to get a automation into a process? commodo does not need any labeling of wheels or manual selection of an undeformed area. This is done automatically by sophisticated methods. The displacement can be split in two parts for further analysis

• dislocation is how a part moves without changing its shape

• deformation the portion on the displacement which describes the change of the shape