Vol.1, No1, 2001, pp. 23-28
UDC 620.178.7:669

Material behaviour under high strain-rate conditions is of practical importance in such problems as the response of structures to blast and impulsive loads, contact stresses under high-speed bearings, high-speed machining and explosive welding. The basic difference of impulse loading compared to static loading is that its effect is not instantaneously transmitted to all parts of the solid body. Deformation and stress produced by the impulse load move through the body in a form of so-called shock waves. During spread of these waves and their reflection, development of spall in the structure is possible. Consequently, during the short typical time of shock loading, for example from 10^-4 to 10^-6 seconds for explosion, development of stresses of magnitudes up to 10 GPa is possible. On the other hand, penetration of projectiles can develop adiabatic shear bands as a result of an very intensive local deformation. All of the mentioned above presents the basis for damage assessment of metallic structures as the result of NATO bombing. This paper describes basic theoretical mechanisms of damage under high-strain rate deformation and examples of case studies from testing of such damaged structural components.

Keywords: line spring model, surface cracks, Dugdale's model, crack driving force