DYNAMIC COMPRESSION TESTING OF METALLIC MATERIALS ESIS PROGRESS TOWARDS A EUROPEAN STANDARD A. Doig 1 and H. Taylor 2 1 Centre for Materials Science and Engineering, Cranfield University, Royal Military College of Science, Shrivenham, Swindon, SN6 8LA, UK 2 Department of Mechanical Engineering, Design and Manufacture, Manchester Metropolitan University, Manchester, M1 5GD, UK ABSTRACT This paper describes the progress of ESIS committee TC5 towards a proposed European Standard for Dynamic Compression Testing of Metallic Materials at room temperature. The problems of compression testing using solid cylinder specimens are discussed, with suggested ways to overcome some. A draft standard has been written, proposing 4 test methods. They are outlined together with early experiences of round-robin testing. INTRODUCTION ESIS technical sub-committee TC5 is interested in mechanical testing of metallic materials at strain rates up to around 104 s-1 - ‘dynamic testing at intermediate strain rates’. A conventional tensile test (for instance) on a 50mm gauge length specimen is usually done at a crosshead speed no higher than 10mm per minute, giving a strain rate of about 3.10-3 s-1 - ‘quasi-static testing’. For dynamic testing of sensible sized specimens, crosshead speeds should be above 5 m s-1 and so instrumented Charpy pendulums, high speed servohydraulic test machines and instrumented drop towers are used. Over the past 12 years or so TC5 has been developing European test standards, starting with dynamic fracture toughness KId on pre-cracked Charpy specimens. Subsequent work has included dynamic tensile testing (now past the round-robin stage) and most recently dynamic compression test methods. Compression Testing Most compression testing is done on solid circular cylinder specimens squeezed between plane platens. This of course gives rise to significant frictional forces acting on the cylinder end-faces, which then cause artificially high load values at the load cell. The most well known existing test standard for metallic materials is ASTM E 9 - 81 [1] and it recommends reducing end-face friction by using PTFE shims or fluid lubricants. Diameter to length ratios D0/L0 of solid cylinder specimens are usually between 3/1 and 0.5/1. Shorter fatter cylinders tend to ‘barrel’ as they compress, and longer thinner cylinders tend to buckle or shear
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