海洋冻融环境下隔震支座橡胶材料性能及其Mooney-Rivlin模型参数研究

Study on properties of rubber material used in rubber isolation bearing and its Mooney-Rivlin constitutive parameters under marine freeze-thaw environment

为研究橡胶隔震支座在海洋冻融循环作用下的劣化规律,对支座的橡胶材料开展海洋冻融循环试验和力学性能试验,分析了在海水冻融循环作用下橡胶材料硬度、定伸应力、扯断伸长率等的劣化规律,揭示了Mooney-Rivlin本构模型参数在海水冻融循环作用下的时变规律,利用橡胶材料时变本构模型进行橡胶隔震支座力学性能有限元分析,并将支座水平刚度和竖向刚度的试验值和有限元分析值进行对比。结果表明:海水冻融循环作用下,橡胶材料外观变化不显著;硬度比随试验时间呈指数增大;扯断伸长率随试验时间呈指数下降;定伸应力随试验时间增加而增大,且伸长率越大其拉伸应变增长幅度越大;橡胶材料本构Mooney-Rivlin模型的正定常数C_(10)随试验时间增加呈指数增大,而正定常数C_(01)则线性减小;将支座水平和竖向刚度的有限元分析值与试验值进行对比,验证了所提出橡胶材料时变本构参数的正确性。

In order to study the deterioration law of rubber isolation bearings under the action of marine freeze-thaw cycles,marine freeze-thaw cycle tests and mechanical property tests were carried out on the rubber materials of the bearings.The deterioration laws of hardness,stress at definite elongation and elongation at break of rubber material under the seawater freeze-thaw cycles were analyzed.The time-varying law of Mooney-Rivlin constitutive model parameters under the action of seawater freeze-thaw cycles was also revealed.The finite element analysis of the mechanical properties of the rubber isolation bearing was carried out by using the time-varying constitutive model parameters of rubber material,and the test and simulation values of the horizontal and vertical stiffness of bearing were compared to verify the correctness of the proposed time-varying constitutive parameters of rubber material.The results show the appearance of rubber material does not change significantly under the action of seawater freeze-thaw cycle test.The hardness ratio increases exponentially with the test duration.The elongation at break decreases exponentially with the test duration.The constant elongation stress increases with the test duration,and the greater the elongation,the greater the increase of tensile strain.The parameter C_(10)of rubber material Mooney-Rivlin model increases exponentially with test duration,while C_(01)decreases linearly.The correctness of the proposed time-varying constitutive parameters of rubber material is verified by comparing the finite element simulation values of the horizontal and vertical stiffness of the bearing with the test values.