利用MTS New 810电液伺服材料试验机,对不同强度的建筑钢筋在地震作用应变率范围(2.5×10-4/s～0.1/s)内的动态特性进行了试验研究。采用单调拉伸、常幅值循环和变幅值循环三种加载方式,加载过程由应变控制并保持应变率恒定。试验...利用MTS New 810电液伺服材料试验机,对不同强度的建筑钢筋在地震作用应变率范围(2.5×10-4/s～0.1/s)内的动态特性进行了试验研究。采用单调拉伸、常幅值循环和变幅值循环三种加载方式,加载过程由应变控制并保持应变率恒定。试验结果表明,钢筋的力学和变形性能在不同加载方式下均有应变率敏感性,应变率敏感性的大小与准静态屈服强度密切相关,相同应变率下循环加载的骨架曲线与单调加载的拉伸曲线基本重合。对试验数据进行回归分析,得到了钢筋的力学性能特征值和变形性能特征值随应变率变化的规律,进而结合Hoehler模型提出了一种钢筋动态循环本构模型,与试验结果对比表明该模型能很好地描述钢筋的动态行为,建议的钢筋动态本构模型可以应用在钢筋混凝土结构抗震分析中。展开更多
A discussion of several kinematic hardening rules based on nonproportional cyclic experiments of 42CrMo steel is presented. They include Prager, Ziegler, Chaboche, Mroz and Tseng Lee hardenin...A discussion of several kinematic hardening rules based on nonproportional cyclic experiments of 42CrMo steel is presented. They include Prager, Ziegler, Chaboche, Mroz and Tseng Lee hardening rules. It shows that Mroz and Tseng Lee rule related to a two surface model has the latent potentiality to describe the nonproportional cyclic hardening behaviors, and a simple two surface model is presented.展开更多
An equivalent visco-elastic model of saturated soft clay was studied under unconsolidated undrained (UU) condition, which can be used to evaluate the stability of ocean foundation. Cyclic triaxial compression and exte...An equivalent visco-elastic model of saturated soft clay was studied under unconsolidated undrained (UU) condition, which can be used to evaluate the stability of ocean foundation. Cyclic triaxial compression and extension tests were conducted to study the parameters of the model. Results showed that the relationships of the damping ratio and the octahedral shear modulus with the octahedral cyclic shear strain were nearly unique, when the initial octahedral shear stress ratios of specimens were equal to 0.3, 0.5 and 0.7. The relationships of the damping ratio and the octahedral shear modulus with the octahedral cyclic shear strain determined from the cyclic triaxial compression tests were basically the same as those determined from the cyclic triaxial extension tests. Furthermore, the relationships were not related to the initial stress condition, the test stress state and the octahedral cyclic shear stress ratio. The relationships determined from the cyclic triaxial tests under no deviatoric stress were basically the same as those determined from the cyclic triaxial tests under deviatoric stress. The change of the octahedral cyclic accumulative strain with the number of cycles was unique under different tests stress states. An equivalent visco-elastic constitutive model of saturated soft clay under UU condition was initially established.展开更多
文摘利用MTS New 810电液伺服材料试验机,对不同强度的建筑钢筋在地震作用应变率范围(2.5×10-4/s～0.1/s)内的动态特性进行了试验研究。采用单调拉伸、常幅值循环和变幅值循环三种加载方式,加载过程由应变控制并保持应变率恒定。试验结果表明,钢筋的力学和变形性能在不同加载方式下均有应变率敏感性,应变率敏感性的大小与准静态屈服强度密切相关,相同应变率下循环加载的骨架曲线与单调加载的拉伸曲线基本重合。对试验数据进行回归分析,得到了钢筋的力学性能特征值和变形性能特征值随应变率变化的规律,进而结合Hoehler模型提出了一种钢筋动态循环本构模型,与试验结果对比表明该模型能很好地描述钢筋的动态行为,建议的钢筋动态本构模型可以应用在钢筋混凝土结构抗震分析中。
文摘A discussion of several kinematic hardening rules based on nonproportional cyclic experiments of 42CrMo steel is presented. They include Prager, Ziegler, Chaboche, Mroz and Tseng Lee hardening rules. It shows that Mroz and Tseng Lee rule related to a two surface model has the latent potentiality to describe the nonproportional cyclic hardening behaviors, and a simple two surface model is presented.
基金Supported by National Natural Science Foundation of China ( No. 51179120)
文摘An equivalent visco-elastic model of saturated soft clay was studied under unconsolidated undrained (UU) condition, which can be used to evaluate the stability of ocean foundation. Cyclic triaxial compression and extension tests were conducted to study the parameters of the model. Results showed that the relationships of the damping ratio and the octahedral shear modulus with the octahedral cyclic shear strain were nearly unique, when the initial octahedral shear stress ratios of specimens were equal to 0.3, 0.5 and 0.7. The relationships of the damping ratio and the octahedral shear modulus with the octahedral cyclic shear strain determined from the cyclic triaxial compression tests were basically the same as those determined from the cyclic triaxial extension tests. Furthermore, the relationships were not related to the initial stress condition, the test stress state and the octahedral cyclic shear stress ratio. The relationships determined from the cyclic triaxial tests under no deviatoric stress were basically the same as those determined from the cyclic triaxial tests under deviatoric stress. The change of the octahedral cyclic accumulative strain with the number of cycles was unique under different tests stress states. An equivalent visco-elastic constitutive model of saturated soft clay under UU condition was initially established.
