hi,
In autodesk simulation mechanical, how do I fix a point in one direction. the poit will be fixed so that movement in the +ve y direction is prohibited while it is alllowed in the -ve direction
thanks
these options are available only in nonlinear analysis. but from there I can choses linear eleastic model for natural frequency analysis. any how to be exact the model is about soil (elastic cube) the top layer can not move in the upper direction it can only compress so how can I achieve this exactly.
Hi steelix,
I understood your first post (how to prevent a node from moving in + direction but free in the - direction), but I did not understand your second post (something about natural frequency).
A natural frequency (modal) analysis cannot contain any type of nonlinearity. Restraining a node in one direction only would be a nonlinear effect. So you will not be able to perform a modal analysis with the node restrained as such.
The elements that Shoubing mentioned (coupling, contact, or general contact elements) have a similar element type in linear stress. In linear, the element type is "Gap". The element definition lets you define whether the gap element works in compression (similar to nonlinear's "contact element") or tension (similar to nonlinear's "coupling" element). If you literally have just one node (or a few), you can draw the lines from the node(s) out to a free area in space, define the lines to be gap/contact elements, and fully constrain the free end of the elements. If you have a "surface" to prevent one-way motion, you can draw another part that matches the surface and use surface contact between the parts.
Hope this helps.