УПРУГОПЛАСТИЧЕСКАЯ МОДЕЛЬ ДЕФОРМИРОВАНИЯ НЕКОТОРЫХ ПОРОД ДРЕВЕСИНЫ, УЧИТЫВАЮЩАЯ СКОРОСТНОЕ УПРОЧНЕНИЕ

Abstract

The problem of ensuring the safe transportation of explosive goods by means of protective structures that use wood as a damper is being investigated. One of the solutions to this problem is damping the impact energy using structural designs. Wood is often used as damping material in such protective structures. In the present report, Cowper - Symonds parameters of the elastoplastic model of some of wood species are determined, accounting for strain rate. The proposed model does not account for anisotropy, which is characteristic of wood. Use of an isotropic model is justified by the fact that, in realistic protective structures, the direction of fibers is chosen so as to provide admissible loading of the protected cargo. Using an isotropic model in this case makes it possible to describe accurately enough deformation of a realistic protective structure. Such a model is simpler from the viewpoint of choosing its parameters, as compared with a model accounting for anisotropy.The model of deformation of pine, birch and aspen, considered in the report, accounts for the strain-rate effect in the range of 600-3000 s-1. High-rate damping is accounted for by choosing parameters of the Cowper - Symonds model. The parameters were chosen, based on the experimental data on dynamic compression of specimens with various kinds of fiber orientation relative to the impact direction (0, 30, 45, 60, 90°). The numerical modeling was done using the chosen parameters of the model. The deformation diagrams obtained using the above model are compared with the experimentally obtained ones. The comparison showed acceptable model accuracy.