Experimental study of deformation properties of a package of woven metal mesh under dynamic and quasi-static stressing

The multilayer gas-permeable bags of woven metal meshes are a promising damping element that protects the structure from shock and explosive effects. Due to the developed interface, the packages may select a significant proportion of the explosion energy of hot products and reduce the intensity of shock waves. Mesh bags are constructively formed by a free deposition of layers on each other while maintaining the directions of threads, so the packages can be considered as a highly porous deformable medium having orthotropic properties. Experimental studies have been made on deformation and strength properties of structurally orthotropic packages of woven metal grids under static and dynamic stressing. Mesh Package resists compression normal to the layers of the grid, it is the first orthotropy axis, and resists the stretching along the directions of threads, it is the other orthotropy axis. For the impact stretching in the plane of the layers we used an analogue of Nicholas circuit which is a modification of the Kolskiy method. In the split Hopkinson bars we made longitudinal grooves which house and fix the test specimen. Shock stretching is carried out in the wave of stretching which emerges in the bars as a result of reflection from the free end of the primary compression wave that passes the junction of rods without deforming the sample. Static stretching of grid samples is performed using Zwick testing machines. Tests were carried out for samples with different pitch and weave meshes and a different number of layers. Experiments have determined the necessary dimensions of the working part of the sample. It is shown that the stress-strain diagram in tension along the threads in the plane of the layers and the compressive normal to the layers of the grid for all loading conditions are non-linear and irreversible, but also show a significant dependence on the strain rate. In the quasi-static tensile packages of grids in the direction of the filaments is significantly affected by their prior compression normal to the layers of mesh. Under dynamic stretching this effect is much weaker.