*CHANGE CONTACT TYPE

Keyword type: step

With this option one can change the contact type at the start of a *DYNAMIC step from “SURFACE TO SURFACE'“ to “NODE TO SURFACE” or “MASSLESS” (the latter only in a *DYNAMIC,EXPLICIT step). This is usually done when a dynamic calculation is performed starting from steady state obtained from a previous *STATIC step.

Indeed, in a static calculation the “SURFACE TO SURFACE” contact type or “MORTAR” contact types usually perform much better (better convergence and better results) than “NODE TO SURFACE” (“MASSLESS” is not available in a static step). In a dynamic calculation performed by integration in time the “SURFACE TO SURFACE” contact, however, is too slow and too detailed in resolution of the contact area. Here, “NODE TO SURFACE” and “MASSLESS” perform better. Therefore, the present keyword was introduced in order to change the contact formulation at the start of a dynamic step.

The option *CHANGE CONTACT TYPE can also be used if a previous static step was calculated with “NODE TO SURFACE” contact (for whatever reason) and the subsequent dynamic step is to be performed with “MASSLESS” contact.

Either the parameter TO NODE TO SURFACE or TO MASSLESS is required.

First and only line:

• *CHANGE CONTACT TYPE
• Enter TO NODE TO SURFACE or TO MASSLESS (actually, blanks in the input deck are immaterial, one might also write TONODETOSURFACE and TOMASSLESS).

Example:

*CHANGE CONTACT TYPE,TO MASSLESS

Example files: changecontacttype1, changecontacttype2.