Contact Joints...

Contact regions may be defined between two surfaces of a model. By defining contact you are allowing those surfaces to pull apart from each other but they may not penetrate each other with the applied load. In addition to the normal stress and deflection plots, contact simulation also will calculate results and measures for contact pressure, contact force and contact area.

Almost every connection in a typical assembly has some type of contact between parts. It may be important to model this effect to either obtain the correct boundary conditions or stiffness across the interface or to calculate the local contact stresses that may be of interest.

Why not define contact for every joint where it may apply?

A contact simulation is nonlinear and requires an iterative solution technique. This can increase run times by orders of magnitude when compared to running the same models without contact. Also, contact is only valid for small deflection Static simulations. It does not work for Modal, Vibration or Thermal simulations and does not support friction. For practical reasons you should limit the use of contact, applying it only where required.

Basic rules for using the contact option in Pro/MECHANICA:

Contact allows two surfaces to pull apart but they cannot penetrate.

The 2 surfaces must be parallel to within 36 degrees.

A normal vector somewhere on the first selected surface must intersect the second surface selected.

The maximum distance between the 2 surfaces must be less than half the average diagonal distance across the 2 surfaces.

MECHANICA does not support friction or sliding.

Contact may only be used between solid elements in models, no shell contact.

Contact analysis only works for static loads.

More contact simulation topics:

> Contact Definition
> Analysis and Convergence Definition
> Crack in the Model Error
> Insufficiently Constrained Error

<TSD Engineering HOME>

Copyright 2003, TSD Engineering