Еrosion damage under pulsed drop-impact loadings

Abstract

Material behavior under impulse drop-impact loading is considered. The process of interaction of the drop with the surface of the barrier is described. The most stressed areas capable of fracture are revealed. The hydraulic pressure acting on the contact surface is shown. The processes occurring at impact of part of the liquid with a material are described step by step. At the first stage, stress and strain waves appear in the material and in part of the liquid. Further drops of liquid embed into the barrier and their depth of embedding depends on the ratio of the power of external impact to the power of deformation of the material corresponding to its destruction. During the third stage, shock wave attenuation in the material and inertial expansion of the crater occur.

Under shock loading conditions, when shear stresses are greater than the yield criterion, a plastic wave appears in the material, the speed of which is not constant and depends on the features of strain hardening of micro-volumes of the material. The change in the velocity of this plastic wave is taken into account by the critical impact velocity - an integral characteristic responsible for deformation of the material up to fracture.

A dynamic characteristic, such as the critical value of strain power density or the critical value of strain energy density, characterizing the energy content of materials under external impact and their rate response to the strain is proposed.