SIMULATION OF VISCOELASTIC-PLASTIC BEHAVIOR OF SHALLOW SHELLS WITH ACCOUNT FOR STRAIN RATE OF MATERIALS

This paper describes a numerical-analytical model of the viscoelastic-plastic behavior of flexible shallow shells with account for the dependence of plastic properties of their materials on strain rate. The inelastic behavior of materials is described by the theory of flow with isotropic hardening. Loading functions depend on the hardening parameter and strain rate intensity. Viscoelastic behavior is described by linear constitutive equations from a multiconstant body model. Transverse shears of structures during bending deformation are taken into account within the framework of the Ambartsumyan theory, and geometric nonlinearity within the von Karman approximation. A cross-type explicit scheme is used for the numerical integration of the formulated initial boundary value problem. The dynamic deformation of a cylindrical elongated panel made of a polymer material is studied. The structure is transversely loaded by a pressure generated by an air blast wave. It is shown that neglecting the dependence between the plastic properties of the material and the strain rate may cause one to significantly underestimate a maximum deflection in absolute value and the largest strain value during oscillations and cause one to overestimate a maximum residual strain. In addition, residual deflection diagrams obtained by such a calculation do not agree with the diagrams obtained by a calculation that takes the mentioned dependence into account.