Experimental and numerical study of the fragmentation of expanding warhead casings by using different numerical codes and solution techniques

• Published in: Defence Technology（防务技术） Vol. 10; no. 2; pp. 161 - 176
• Main Authors: Moxnes, John F., Prytz, Anne K., Frøyland, Øyvind, Klokkehaug, Siri, Skriudalen, Stian, Friis, Eva, Teland, Jan A., Dørum, Cato, Ødegårdstuen, Gard
• Format: Journal Article
• Language: Chinese; English
• Published: Elsevier B.V 01.06.2014; Land Systems Division, Norwegian Defence Research Establishment, P.0. Box 25, N0-2027 Kjeller, Norway%Nammo Raufoss AS, P.0. Box 162, N0-2831 Raufoss, Norway; KeAi Communications Co., Ltd
• Subjects: Fracture model; Fragmentation; LS-DYNA; Simulation; Warhead; 光滑粒子流体动力学; 外壳; 弹头; 技术试验; 数值模拟; 数值求解方法; 数字代码; Warhead; Simulation; Fracture model; Fragmentation
• ISSN: 2214-9147; 2214-9147
• DOI: 10.1016/j.dt.2014.05.009

There has been increasing interest in numerical simulations of fragmentation of expanding warheads in 3D. Accordingly there is a pressure on developers of leading commercial codes, such as LS-DYNA, AUTODYN and IMPETUS Afea, to implement the reliable fracture models and the efficient solution techniques. The applicability of the Johnson-Cook strength and fracture model is evaluated by comparing the fracture behaviour of an expanding steel casing of a warhead with experiments. The numerical codes and different numerical solution techniques, such as Eulerian, Lagrangian, Smooth particle hydrodynamics （SPH）, and the corpuscular models recently implemented in IMPETUS Afea are compared. For the same solution techniques and material models we find that the codes give similar results. The SPH technique and the corpuscular technique are superior to the Eulerian technique and the Lagrangian technique （with erosion） when it is applied to materials that have fluid like behaviour such as the explosive and the tracer. The Eulerian technique gives much larger calculation time and both the Lagrangian and Eulerian techniques seem to give less agreement with our measurements. To more correctly simulate the fracture behaviours of the expanding steel casing, we applied that ductility decreases with strain rate. The phenomena may be explained by the realization of adiabatic shear bands. An implemented node splitting algorithm in IMPETUS Afea seems very promising.