LOADING CONDITION FOR SPECIMEN DEFORMATION AT CONSTANT STRAIN RATE IN SHPB TEST OF ROCKS
ZHOU Zilong1，2，LI Xibing1，YAN Xiaoming1
(1. School of Resources and Safety Engineering，Central South University，Changsha，Hunan 410083，China； 2. Postdoctoral Work Station of Jiangxi Copper Corporation，Guixi，Jiangxi 335400，China)
Abstract：The relationships among specimen stress，incident stress，reflected stress and transmitted stress were analyzed；and the loading condition for specimen deformation at constant strain rate was found out，i. e.，only when the loading stress and deformation stress in specimen have the same changing pattern，the specimen deforms at a constant strain rate. The tests show that constant strain rate of specimen can be achieved by pulse shaper method and special shape striker method. Double specimen method is actually a special case of pulse shaper method. Pulse shaper method is favorable for tests of perfect elastic brittle material. And special shape striker method is useful for the split Hopkinson pressure bar(SHPB) tests of materials with power function constitutive relation or materials with no foregone constitutive information. Special shape striker method has more repeatability than pulse shaper method. Special shape striker method with half-sine incident wave can reduce the influences caused by wave dispersion.
