The relationship between the protective performance of flexible polymer material and material parameters(elasticmodulus,viscosity coefficient)is explored,an impact collision motion equation between two bodies is estab...The relationship between the protective performance of flexible polymer material and material parameters(elasticmodulus,viscosity coefficient)is explored,an impact collision motion equation between two bodies is establishedfrom the viscoelastic material constitutive,and the relationship between the kinematic response and the materialparameters is obtained.Based on the Kelvin constitutive model,a theoretical model for impact between the pro-tective body and the protected body is established,then the dynamic response is obtained.The feasibility of themodel was verified by drop hammer experiment,and the material parameters(elastic modulus,viscosity coeffi-cient)were obtained by formula.The model is discretized and the relationship between local impact response andmaterial parameters is analyzed.The discussion results on the relationship between the impact response and theprotective material performance indicate that adjusting the elastic modulus,viscosity coefficient,and thicknessof the protective material can effectively improve protective effect.展开更多
The experimental study on the volume fraction of retained austenite for QP980CR steel under high-strain-rate tension is briefly described. An interrupted tensile split Hopkinson bar （TSHB） is developed to control th...The experimental study on the volume fraction of retained austenite for QP980CR steel under high-strain-rate tension is briefly described. An interrupted tensile split Hopkinson bar （TSHB） is developed to control the elongation of specimens. The QP980CR steel sam- ples recovered from the interrupted TSt-IB tests are investigated using synchrotron X-ray diffraction （XRD） to analyze the effects of strain and strain rate on the martensitic trans- formation of retained austenite. A constitutive model of QP980CR steel coupling with the transformation-induced plasticity （TRIP） effect is presented based on Delannay＇s mean-field modeling. The stress-strain curves of quasi-static and dynamic tensile tests for QP980CR steel are compared with the results predicted by the presented constitutive model. The dif- fuse necking of QP980CR steel sheet specimens in TSHB tests is analyzed using Batra and Vv＇ei＇s instability criterion and the presented constitutive model. The effects of strain rate and temperature on the dynamic tensile fracture strain of QP980CR steel are also given.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.12172151 and 12172149).
文摘The relationship between the protective performance of flexible polymer material and material parameters(elasticmodulus,viscosity coefficient)is explored,an impact collision motion equation between two bodies is establishedfrom the viscoelastic material constitutive,and the relationship between the kinematic response and the materialparameters is obtained.Based on the Kelvin constitutive model,a theoretical model for impact between the pro-tective body and the protected body is established,then the dynamic response is obtained.The feasibility of themodel was verified by drop hammer experiment,and the material parameters(elastic modulus,viscosity coeffi-cient)were obtained by formula.The model is discretized and the relationship between local impact response andmaterial parameters is analyzed.The discussion results on the relationship between the impact response and theprotective material performance indicate that adjusting the elastic modulus,viscosity coefficient,and thicknessof the protective material can effectively improve protective effect.
基金supported by the National Natural Science Foundation of China(nos.11372149 and 11572164)the Zhejiang Provincial Key Science and Technology Innovation Team(2013TD21)programK.C.Wong Magna Fund in Ningbo University
文摘The experimental study on the volume fraction of retained austenite for QP980CR steel under high-strain-rate tension is briefly described. An interrupted tensile split Hopkinson bar （TSHB） is developed to control the elongation of specimens. The QP980CR steel sam- ples recovered from the interrupted TSt-IB tests are investigated using synchrotron X-ray diffraction （XRD） to analyze the effects of strain and strain rate on the martensitic trans- formation of retained austenite. A constitutive model of QP980CR steel coupling with the transformation-induced plasticity （TRIP） effect is presented based on Delannay＇s mean-field modeling. The stress-strain curves of quasi-static and dynamic tensile tests for QP980CR steel are compared with the results predicted by the presented constitutive model. The dif- fuse necking of QP980CR steel sheet specimens in TSHB tests is analyzed using Batra and Vv＇ei＇s instability criterion and the presented constitutive model. The effects of strain rate and temperature on the dynamic tensile fracture strain of QP980CR steel are also given.
