INELASTIC RESPONSE OF A DEEP CRACK SINGLE-EDGE NOTCH SPECIMEN UNDER IMPACT LOADING

Three-dimensional dynamic analyses are performed for a single-edge ben d, SE(B), fracture specimen (a/W = 0.5) subjected to impact loading. L oading rates obtained in routine drop tower tests (terminal load-line velocity of 100 in./s or 2.54 m/s) are applied in the analyses. Explic it time integration coupled with an efficient element integration sche me is used to compute the dynamic response of the specimen. Strain-rat e sensitivity is introduced via a new, efficient implementation of the Bodner-Partom viscoplastic constitutive model. Material properties fo r A533B steel (a medium strength pressure vessel steel) are used in th e analyses. Static analyses of the same SE(B) specimens provide baseli ne results from which inertial effects are assessed. Similarly, dynami c analyses using a strain-rate insensitive material provide a referenc e for the assessment of strain rate effects. Strains at key locations and the support reactions are extracted from the analyses to assess th e accuracy of static formulas commonly used to estimate applied J valu es. In ertial effects on the applied J are quantified by examining the acceleration component of J. Results show that dynamic effects for th e steel analyzed are negligible after twice a characteristic time that can be defined in terms of the first elastic period of the specimen.