球铰装置对混凝土材料轴拉全过程试验的影响

Effect of Spherical Hinge Equipment on the Complete Uniaxial Tensile Test for Concrete

采用MTS322电液式伺服试验机,进行了试验系统轴拉刚度律定试验以及混凝土材料轴拉全过程试验,分析了球铰装置对混凝土材料轴拉全过程试验的影响.结果表明:球铰装置大大降低了加载系统的刚度,且试验机作动头位移与试件本身的变形间不遵循线性规律;用作动头位移控制加载,有限提高球铰装置刚度并不能使混凝土材料稳定断裂,只有采用试件实时最大应变控制加载,才有可能得到稳定的混凝土材料断裂,从而获得混凝土材料轴拉应力-应变全曲线.

The stiffness calibration tests for test system and the complete uniaxial tensile tests for concrete were done on a MTS322 electro-hydraulic servo testing machine, and the effects of spherical hinge equip- ment on the complete uniaxial tensile test for concrete were analyzed. The results show that the stiffness of loading system is greatly reduced by spherical hinge equipment, in addition, the relation between the displacement of actuator and the deformation of concrete specimen does not follow a linear rule. Besides, it can not make the fracture process of concrete stable by increasing the stiffness of spherical hinge equipment in a limited range when using the displacement of actuator to control loading. Only using the maximum strain of concrete specimen to control loading, a complete uniaxial tensile stress-strain curve of concrete can be achieved.