Structural & Thermal

Structural & Thermal

During a buckling analysis pre-stressed by a non-linear analysis involving plasticity, is it the initial Young Modulus or the Tangent Modulus that is taken into account ?

    • FAQFAQ
      Participant

      By default, in Mechanical Workbench, it is the initial Young Modulus that is taken into account. Indeed, to conduct the buckling analysis, Mechanical uses the PERTURB APDL command with Matkey=AUTO, and the help provides the following information: “AUTO – For any nonlinear materials other than hyperelastic materials used in the base analysis, the material properties are assumed to be linear elastic in the linear perturbation analysis. The material data is the same as the linear portion of the nonlinear materials (that is, the parts defined by MP commands).” If you would like to use the Tangent Modulus, an analysis with Matkey=TANGENT option has to be performed. Indeed, for this value of MatKey, the help states: “TANGENT – For any nonlinear materials other than hyperelastic materials used in the base analysis, the material properties are obtained via the material tangent on the material constitutive curve at the restart point of the base analysis.”