J. Cirne, R. Dormeval, et al.
J. Phys. IV France 134 (2006) 591-596
A microstructural investigation of “machining rings” and deformation uniformity for dynamic ring compression testsT.J. Cloete, R.S. Hartley and G.N. Nurick
Blast Impact and Survivability Research Unit (BISRU), Department of Mechanical Engineering, University of Cape Town, Private bag X3, Rondebosch 7701, South Africa
Published online: 26 July 2006
A series of ring compression tests, conducted both quasi-statically (using a Zwick tensile test machine) and dynamically (using a split Hopkinson bar) are presented. The friction conditions were inferred from the behaviour of the inner diameter of the ring specimen using the analysis of Avitzur. Both quasi-static and dynamic specimens displayed machining rings. Microstructural analysis revealed that under quasi-static conditions the machining rings correlate with fold-over, while under dynamic conditions machining rings can appear without fold over. This indicates that machining rings formed during dynamic tests may be due to lubrication breakdown. The results indicate that the assumption of uniform specimen deformation is reasonable for strains attainable during split Hopkinson bar tests.
© EDP Sciences 2006