| Popis: |
The results of numerical simulation of elastoplastic compression of symmetrical fragments of a package of woven steel meshes are presented. The thickness of the symmetrical fragment is one and two layers. The study was carried out under dynamic loading conditions in the ANSYS LS-DYNA computer system. The mesh package is formed by superimposing layers on top of each other while maintaining the direction of the wires. The packet has a quasi-periodic structure; therefore, symmetrical fragments can be distinguished. For two mesh layers, a fragment is accepted, taking into account the shift of the layer in the lateral directions by half the size of the cell. The compression was carried out by a pair of absolutely rigid plates moving symmetrically towards each other at a constant speed for a given time interval. A multilinear plasticity model with isotropic hardening was used to describe the behavior of the material. If the maximum specified deformation is exceeded in the calculation, the diagram automatically continues with a small linear hardening modulus. A comparative analysis of numerical solutions for the compression of symmetrical fragments from one and two layers of a woven mesh is carried out. When the fragments are compressed, a strongly uneven stress-strain state arises in the wires, especially large irreversible deformations occur in the knots of weaving. The deformation curves of the fragments have characteristic inflections associated with the fact that the deformation process includes not only knots of weaving, but also deformations of wire compression along its entire length. The numerical results are compared with the experimental dynamic compression curve of a multilayer mesh package. The compression curves are different for one and two layers. For two layers of grids, the deformation curve at low pressure is more consistent with the experimental data. Two stages of behavior of the deformation diagram are observed at low and high degrees of compression, the characteristic inflection is formed somewhat earlier than in the numerical solution for one layer. Numerical dependences of the relative area of the normal and lateral passage sections of a symmetrical fragment of a mesh package on the compression strain are obtained. These data can be used to simulate the propagation of shock waves through multilayer woven mesh packages. |
