A simplified calculation of the specimen’s stress-strain curve is generally conducted using the two-wave method by the split Hopkinson pressure bar(SHPB),which aligns the onset of the transmitted and reflected waves....A simplified calculation of the specimen’s stress-strain curve is generally conducted using the two-wave method by the split Hopkinson pressure bar(SHPB),which aligns the onset of the transmitted and reflected waves.However,this approach neglects the travel time of elastic waves within the specimen.Considering the travel time of elastic waves,this study quantitatively investigates the error characteristics and patterns of stress,strain,and strain rate in the specimen under different conditions using the theoretical two-wave method,and compares the results with those obtained using the onset-aligned twowave method.The study reveals that the stress-time curves derived from the theoretical two-wave method are lower than the actual stress curves,whereas those obtained from the onset-aligned two-wave method are consistently higher than the actual stress curves,with the stress deviation approximating a constant value when the dimensionless time exceeds 2.0.The starting point of the stress-strain curves obtained by the theoretical two-wave method is not zero but a point on the strain axis,whereas the onset-aligned two-wave method always starts at zero.However,the slopes of the stress-strain curves obtained by both methods differ from the actual Young’s modulus of the material,and functional relationships between the slopes and the actual Young’s modulus are provided.This research offers theoretical guidance for the refined design of SHPB experiments and the accurate processing of data.展开更多
This paper proposed the split short Hopkinson pressure bar(SSHPB)with short incident and transmission bars to investigate the dynamic compression characteristics of sandstone under different strain rates.The SSHPB was...This paper proposed the split short Hopkinson pressure bar(SSHPB)with short incident and transmission bars to investigate the dynamic compression characteristics of sandstone under different strain rates.The SSHPB was constructed to carry out impact tests to obtain superimposed stress waves in short bars.The separated stress waves(incident,reflected and transmitted waves)were determined by the proposed wave separation method and further used to determine the stress-strain relationship of sandstone.The SSHPB was validated by comparing the dynamic properties of sandstone determined by the SSHPB with those determined by the traditional split Hopkinson pressure bar(SHPB).The effect of the strain rate on the accuracy of the SSHPB was discussed.The results show that the stress-strain relationship of sandstone determined by the SSHPB agrees well with that determined by the traditional SHPB.The variation in the dynamic properties of sandstone with strain rate determined by the SSHPB is similar to that determined by the traditional SHPB.Under different strain rates,the relative error between the dynamic properties of sandstone determined by the SSHPB and traditional SHPB is less than 5%.Compared with the traditional SHPB,the SSHPB can reduce the length of the incident and transmission bars by 50%,which is an alternative to the traditional SHPB.展开更多
基金supported by the National Natural Science Foundation of China (Grant Nos.U2341244,12172179,and 11772160)the Postgraduate Research&Practice Innovation Program of Jiangsu Province.
文摘A simplified calculation of the specimen’s stress-strain curve is generally conducted using the two-wave method by the split Hopkinson pressure bar(SHPB),which aligns the onset of the transmitted and reflected waves.However,this approach neglects the travel time of elastic waves within the specimen.Considering the travel time of elastic waves,this study quantitatively investigates the error characteristics and patterns of stress,strain,and strain rate in the specimen under different conditions using the theoretical two-wave method,and compares the results with those obtained using the onset-aligned twowave method.The study reveals that the stress-time curves derived from the theoretical two-wave method are lower than the actual stress curves,whereas those obtained from the onset-aligned two-wave method are consistently higher than the actual stress curves,with the stress deviation approximating a constant value when the dimensionless time exceeds 2.0.The starting point of the stress-strain curves obtained by the theoretical two-wave method is not zero but a point on the strain axis,whereas the onset-aligned two-wave method always starts at zero.However,the slopes of the stress-strain curves obtained by both methods differ from the actual Young’s modulus of the material,and functional relationships between the slopes and the actual Young’s modulus are provided.This research offers theoretical guidance for the refined design of SHPB experiments and the accurate processing of data.
基金support from the National Natural Science Foundation of China(Grant Nos.12172019 and 42477210).
文摘This paper proposed the split short Hopkinson pressure bar(SSHPB)with short incident and transmission bars to investigate the dynamic compression characteristics of sandstone under different strain rates.The SSHPB was constructed to carry out impact tests to obtain superimposed stress waves in short bars.The separated stress waves(incident,reflected and transmitted waves)were determined by the proposed wave separation method and further used to determine the stress-strain relationship of sandstone.The SSHPB was validated by comparing the dynamic properties of sandstone determined by the SSHPB with those determined by the traditional split Hopkinson pressure bar(SHPB).The effect of the strain rate on the accuracy of the SSHPB was discussed.The results show that the stress-strain relationship of sandstone determined by the SSHPB agrees well with that determined by the traditional SHPB.The variation in the dynamic properties of sandstone with strain rate determined by the SSHPB is similar to that determined by the traditional SHPB.Under different strain rates,the relative error between the dynamic properties of sandstone determined by the SSHPB and traditional SHPB is less than 5%.Compared with the traditional SHPB,the SSHPB can reduce the length of the incident and transmission bars by 50%,which is an alternative to the traditional SHPB.
