FINITE-ELEMENT MODELING OF LARGE ELASTOPLASTIC DEFORMATIONS OF A SPHERICAL SHELL IN A SCAPHANDER UNDER AN OVERLOAD PULSE
An axisymmetric problem of large deformations of a led spherical shell, placed in an aluminum scaphander, under an overload pulse is considered. The deformation of the shell is described in terms of mechanics of elasto-viscoplastic media in Lagrange variables. Kinematic relations are determined in the metrics of the current state. Equations of state are taken in the form of the flow theory with isotropic hardening. Contact interactions of the shell and the scaphanser are modeled by non-pemetration conditions, accounting for friction. The numerical analysis of the problem for given boundary and initial conditions is based on the moment FEM scheme and the cross-type explicit time integration scheme. Spacial variable discretization is done using 4-node isoparametric finite elements with bilinear form functions. The modeling results schow that in the process of loading the spherical shell undergoes considerable local changes of form characterized by large displacements and rotation angles of the elements as a rigid whole body. The computational results on the residual form show good agreement with the experimental data.