A dynamic investigation of observable void growth and coalescence in pure copper sheets

作者：Ma Dongfang^*; Chen Danian; Wu Shanxing; Wang Huanran; Cai Canyuan; Deng Gaotao

来源：Journal of Applied Physics, 2011, 110(9): 094905.

DOI：10.1063/1.3658623

A combined experimental, theoretical, and numerical investigation of dynamic growth and coalescence of drilled voids in pure copper sheets was performed to visualize void growth and coalescence in a controlled matter. The dynamic constitutive model of the pure copper determined from the first tension loading in the optimized tensile split Hopkinson bar (TSHB) tests for pure copper sheets was adjusted in numerically simulating the large deformation of pure copper sheets generated by the multi-tension loading in the TSHB tests and recorded by a high speed camera. The dynamic growth, coalescence, and evolution post coalescence of drilled simplest cluster voids in pure copper sheets subjected to the multi-tension loading in the TSHB tests were recorded by the high speed camera and simulated by using the adjusted constitutive model of the pure copper and the different criteria for void coalescence. Based on Bandstra's work [J. P. Bandstra et al. Mater. Sci. Eng. A 249, 46 (1998); J. P. Bandstra and D. A. Koss, Mater. Sci. Eng. A 319-321, 490 (2001)], this study presented a stress triaxiality and strain rate (STSR) dependent failure criterion for void coalescence to reveal the void coalescence process. The experimentally recorded void evolution at a certain average strain of pure copper sheets was compared with the numerically simulated results, which involved the STSR dependent failure criterion, the localized Thomason criterion [P. F. Thomason, Ductile Fracture of Metals (Pergamon, 1990); Fatigue Frac. Eng. Matter Struct. 21, 1105 (1998)], and Brown-Embury criterion [L. M. Brown and D. Embury, Proceedings of the Third International Conference on Strength of Metals and Alloys (Institute of Metals, London, 1973), pp. 164-173]. The validity of void coalescence criteria was assessed: the STSR dependent failure criterion could be used to describe the void coalescence process while the localized Thomason criterion and Brown-Embury criterion for void cluster could also match the process of void coalescence to a certain extent.

• 出版日期2011-11-1
• 单位宁波大学