Prediction of controlled fragmentation for cylindrical casing with circumferential grooves.

• An explosion test of a cylindrical casing for AISI9260 is conducted, and the mass distribution of fragmentation is successfully obtained. • Fracture strains at shear, uniaxial tension, and plane strain are obtained at various strain rates from 0.001 to 1500/s, and strain-rate dependent fracture surface are successfully modelled. • The algorithm for fragment mass distribution is developed. • Fragmentation simulation is performed, and the predicted mass distribution show good agreement with the experimental result. • The groove pattern is changed, and more uniform fragments are predicted. This paper presents experimental and numerical studies on the controlled fragmentation of AISI9260 casing under internal explosive loading condition. The cylindrical casing has internal circumferential grooves to get a uniform size of fragments. In order to investigate the fragmentation performance, a fragment mass distribution is obtained from the experiment. Experimental results show that the fragments are created in various sizes. For the material characterization, the mechanical tests are conducted at various strain rates to understand the material dynamic behaviors. For the dynamic hardening behavior, the flow stress increases when the strain rate increases. The stress states and strain rates are considered for the dynamic fracture behavior. Each stress state shows a different strain rate effect. The extended Lim–Huh and Lou–Huh fracture models successfully describe the dynamic hardening and fracture behaviors, respectively. Then, the numerical simulation is performed to figure out the deformation and fragmentation processes. The fragment mass distributions from the experiment and simulation show good agreement with each other. Moreover, the distance between grooves has increased to achieve the uniform size of fragments. It is confirmed that the distance between grooves is a crucial factor for uniform fragments. [ABSTRACT FROM AUTHOR]