The split Hopkinson pressure bar（SHPB） technique and the wave propagation inverse analysis（WPIA） technique are both extensively used to experimentally investigate the impact behavior of materials, although neither...The split Hopkinson pressure bar（SHPB） technique and the wave propagation inverse analysis（WPIA） technique are both extensively used to experimentally investigate the impact behavior of materials, although neither of them alone provides a fully satisfactory analysis. In the present paper, attention is given to new experimental techniques by incorporating a damagemodified constitutive model into the SHPB technique and combining the Hopkinson pressure bar（HPB） technique with WPIA. First, to distinguish the response due to dynamic constitutive behavior and the response due to dynamic damage evolution, the SHPB method incorporating a damage-modified constitutive model is developed, including an explicit damage-modified Zhu–Wang–Tang model and an implicit damage-modified constitutive model. Second, when the SHPB results become invalid, a method of combining new Lagrange inverse analyses with the HPB technique is developed, including cases of the HPB arranged in front of a long specimen and behind the specimen. As examples of these new methods, typical results are given for nonlinear viscoelastic polymers and concretes considering damage evolution, a super-elastic Ti–Ni alloy with phase transformation and an aluminum foam with shock waves propagating within it.展开更多
In the present paper,more attention is paid to develop a new optical measurement approach of split-Hopkinson pressure bar(SHPB)and wave propagation inverse analysis(WPIA)by using multi-channel photonic Doppler velocim...In the present paper,more attention is paid to develop a new optical measurement approach of split-Hopkinson pressure bar(SHPB)and wave propagation inverse analysis(WPIA)by using multi-channel photonic Doppler velocimetry(PDV).Based on the particle velocities measured by PDV,the dynamic stress-strain curve of material is obtained in SHPB tests.The strain is determined by the radial particle velocity of specimen,and the stress is determined by the free surface particle velocity of the transmit ted bar.The results obtained by the new method coincide with those obtained by the conventional strain gauge measurements.The new method is non-intrusive and insensitive to electrical noise,making it significantly more reliable than strain gauges.Using the oblique incidence of laser beam,a series of particle velocity wave propagation signals for long rod specimen are measured simultaneously.Based on the measurements of particle velocity profile,the dynamic constitutive response of polymethyl methacrylate(PMMA)is det ermined by WPIA method.The comparison bet ween the dynamic st ress-s train curve and the quasi-static one indicates that the strain-rate effect must be taken into account for PMMA.展开更多
基金supported by the National Natural Science Foundation of China(No.11032001)the K.C.Wong Magna Fund in Ningbo University
文摘The split Hopkinson pressure bar（SHPB） technique and the wave propagation inverse analysis（WPIA） technique are both extensively used to experimentally investigate the impact behavior of materials, although neither of them alone provides a fully satisfactory analysis. In the present paper, attention is given to new experimental techniques by incorporating a damagemodified constitutive model into the SHPB technique and combining the Hopkinson pressure bar（HPB） technique with WPIA. First, to distinguish the response due to dynamic constitutive behavior and the response due to dynamic damage evolution, the SHPB method incorporating a damage-modified constitutive model is developed, including an explicit damage-modified Zhu–Wang–Tang model and an implicit damage-modified constitutive model. Second, when the SHPB results become invalid, a method of combining new Lagrange inverse analyses with the HPB technique is developed, including cases of the HPB arranged in front of a long specimen and behind the specimen. As examples of these new methods, typical results are given for nonlinear viscoelastic polymers and concretes considering damage evolution, a super-elastic Ti–Ni alloy with phase transformation and an aluminum foam with shock waves propagating within it.
基金supported by the Science Challenge Project under Grant No.TZ2018001the National Science Foundation of China under Grant Nos.11472142 and 11702152the K.C.Wong Magna Fund in Ningbo University,China.
文摘In the present paper,more attention is paid to develop a new optical measurement approach of split-Hopkinson pressure bar(SHPB)and wave propagation inverse analysis(WPIA)by using multi-channel photonic Doppler velocimetry(PDV).Based on the particle velocities measured by PDV,the dynamic stress-strain curve of material is obtained in SHPB tests.The strain is determined by the radial particle velocity of specimen,and the stress is determined by the free surface particle velocity of the transmit ted bar.The results obtained by the new method coincide with those obtained by the conventional strain gauge measurements.The new method is non-intrusive and insensitive to electrical noise,making it significantly more reliable than strain gauges.Using the oblique incidence of laser beam,a series of particle velocity wave propagation signals for long rod specimen are measured simultaneously.Based on the measurements of particle velocity profile,the dynamic constitutive response of polymethyl methacrylate(PMMA)is det ermined by WPIA method.The comparison bet ween the dynamic st ress-s train curve and the quasi-static one indicates that the strain-rate effect must be taken into account for PMMA.
