I am a PhD student at IIT Roorkee, India, working on the high-strain-rate behaviour of materials. I request you to kindly provide the VUMAT Fortran source code implementation of the Holmquist–Johnson–Cook (HJC) material model, which is already available in ABAQUS software as ABQ_HJC_CONCRETE. Access to the source code will significantly help me understand the implementation details for my research work.