Ductile fracture modeling considering thermal softening under ballistic impact

Abstract

and (6) verification of the constructed fracture model through comparison between the high-velocity impact tests and numerical simulations.

(5) construction of a high speed ductile fracture model considering the thermal softening phenomenon

(4) analysis of the physical phenomena through high speed deformation and fracture tests ($10^0/s$ and $10^3/s$)

(3) construction of the quasi-static ($10^{-3}/s$) ductile fracture surface from results of the tensile tests with different loading paths

(2) development of the user-defined material sub-program able to apply the newly suggested material model to numerical simulation

The metallic materials are widely being used in structural bodies of the various military weapons. For military purposes, these materials should inevitably experience high rate deformation and fracture under high-energy events such as ballistic impacts and explosions. In this dissertation, the experimental methodology for the analysis of high speed fracture behaviors of a metallic material have been studied with utilization of Split Hopkinson Tension Bar (SHTB). And effects on the strain localization and fracture behavior by temperature increase at high speed deformation have been also investigated as well. Eventually, high speed fracture surface considering the thermal softening effect has been constructed in order to make practical application to finite element analysis. The main research contents are as follows: (1) construction of SHTB test system in combination with high speed image camera and thermographic IR camera, which can measure the deformation and temperature at the same time by synchronization