Ansys Employee
,nA compression member is usually subjected to two modes of failure 1. Material Failure (yielding) and 2. Buckling. Yielding is when a material crosses its elastic limit and deforms plastically. A von-mises stress criteria is used to predict failure of ductile materials by yielding. Whereas buckling is the sudden change in shape of a structure generally under axial compressive load(there are other modes of buckling as well). Buckling is characterized by a loss of stiffness of the structure, which is indicated by a horizontal force displacement curve in the non linear simulation , after which the solution fails to converge. Please have a look at
which shows how to find the buckling point by tracking the load deflection curve. You need a tiny side load or deformation to initiate buckling. Also, It is better to apply a axial displacement instead of an axial force, this way, the solver does not fail to converge and you could see the buckling load increase to a maximum and then go down with a negative slo pe as structure continues to buckle.nRegards,nIshan.nn