MODELING THE SHOCK RESPONSE OF SILICON-CARBIDE, BORON-CARBIDE AND TITANIUM DIBORIDE

An advanced constitutive model is used to describe the shock and high strain rate behaviors of silicon carbide, boron carbide, and titanium diboride under impact loading conditions. The model's governing equati ons utilize a set of microphysically based constitutive relationships to describe the deformation and damage processes of ceramics. The tota l strain is decomposed into elastic, plastic, and microcracking compon ents. The plastic strain components are calculated using conventional viscoplastic equations. The strain components due to microcracking uti lize relationships derived from a penny shaped crack in an infinite el astic solid. The main features of the model include degradation of str ength and stiffness under both compressive and tensile loading conditi ons. When loaded above the Hugoniot elastic limit (HEL), the strength is limited by the strain rate dependent strength equation. However, be low the HEL, the strength variation with respect to strain rate and pr essure is modeled through microcracking relationships, assuming no pla stic flow. The ceramic model parameters were determined using plate im pact experimental data. Copyright (C) 1996 Elsevier Science Ltd.