摘要:
为了研究不同长径比石灰岩应力-应变曲线、动态单轴抗压强度、动态弹性模量、峰值应变随应变率增大的变化规律,采用分离式霍普金森压杆(SHPB)试验装置,对2组不同长径比石灰岩试样,进行7种不同应变率等级下的冲击加载试验。结果表明:随着应变率的增大,应力-应变曲线在峰值点后表现出不同的变化规律,呈现明显的率相关性;2组试样动态单轴抗压强度均随应变率的增大呈幂指增大,且长径比为1.0的试样强度的应变率敏感性强于长径比为0.5的试样,有明显的尺寸效应;动态弹性模量和峰值应变均随应变率的增大而增大,相同应变率下,长径比为1.0的试样动态弹性模量大于长径比为0.5的试样;试样的动态压缩破坏形态在相同应变率下,长径比为0.5的试样破坏程度比长径比为1.0的大,应变率较低时呈轴向劈裂破坏,应变率较高时呈颗粒状粉碎破坏。
Abstract:
In order to study the stress -strain curve, dynamic uniaxial compression strength, dynamic elastic modulus, peak strain and variation law with the strain rate increased of the limestone with different length-diameter ratios, a Split Hopkinson Pressure Bar (SHPB) test device was applied to the impact loading test under seven different strain rate grades on the two group limestone samples with different length-diameter ratios.The results showed that with the strain rate increased, the stress -strain curve would have different variation law after the peak reached and would have obvious rate dependence. The dynamic uniaxial compressive strength of the two group samples would have a power increased with the strain rate increased. The strength of the sample with a length diameter ratio of 1.0 would have a strong sensitivity of the strain rate than the sample with a length diameter ratio of 0.5 and would have a obvious size effect. The dynamic elastic modulus and the peak strain would be increased with the strain rate increased. Under the same strain rate, the dynamic elastic modulus of the sample with a length diameter ratio of 1.0 would be higher than the sample with a length diameter ratio of 0.5. Under the same strain rate of the dynamic compression failure state of the sample, the failure degree of the sample with a length diameter ratio of 0.5 would be higher than the sample with a length diameter ratio of 1.0. When the strain rate was low, the sample would have a axial split failure. When the strain rate was high, the sample would have a partical fine failure.
百度学术
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