Plate impact experiments to investigate dynamic slip, deformation and failure of materials.

摘要

Determination of co-seismic slip resistance in earth faults is critical for understanding the magnitude of shear-stress reduction and hence the near-fault acceleration that can occur during earthquakes. In the present study plate-impact pressure-shear friction experiments and modified torsional Kolsky-bar friction experiments were employed to investigate the frictional resistance in rocks and analog materials (quartz, soda lime glass), at relevant normal pressures and co-seismic slip rates. The results of this study have relevance not just to mechanisms of dynamic fault weakening, but also to the constitutive description of the behavior that can be used to critically examine the rate and state dependent dynamic friction models of earthquake rupture.; In an attempt to better understand the nature of dynamic friction for metal tribo-pairs, plate-impact pressure-shear friction experiments were employed to investigate dynamic slip resistance and time-resolved growth of molten metal films during dry metal-on-metal (tool-steel on 7075-T6 Al alloy) slip under extreme interfacial conditions. A Lagrangian finite-element code was developed to understand the evolution of the thermo-mechanical fields and their relationship to the observed slip response.; In order to better design and develop GRP-based light-weight integral armor, a series of plate-impact experiments were designed to study spall strength in two glass-fiber reinforced polymer composites (GRP) -- S2 glass woven roving in Cycom 4102 polyester resin matrix and a balanced 5-harness satin weave E-glass in a Ciba epoxy (LY564) matrix. The spall strengths of the two GRP composites were observed to decrease with increasing compression stress and shear strain. The E-glass GRP was found to have a much higher level of spall strength when compared to the S2-glass GRP.; The dynamic response of bulk metallic glasses is of considerable interest for potential applications, such as kinetic energy penetrator. A series of plate-impact experiments were conducted on a Zr-based BMG (Zr41.25Ti 13.75Ni10Cu12.5Be22.5) to: (a) better understand the structure of shock waves in the BMG, (b) estimate residual spall strength of the BMG as a function of normal stress and shear strain, (c) obtain the Hugoniot elastic limit (HEL) of the material, and (d) investigate normal pressure effect on the shear yield stress of the BMG.