基于统计接触特性的金属橡胶支座剪切本构关系

A CONSTITUTIVE MODEL OF METALLIC RUBBER BEARINGS BASED ON STATISTICAL CONTACT PROPERTIES

根据金属橡胶材料内部构造特点和力学性能,将金属橡胶剪切力学模型分解为线性回复力、库仑摩擦力和非线性迟滞力三部分。首先通过对金属橡胶进行层状分解计算得到金属橡胶单一接触对的剪切刚度,结合内部线匝有效接触对数量随剪切变形过程的统计规律,进而得到各力学组成部分的表达式并建立金属橡胶层状剪切本构模型,最后通过金属橡胶支座的剪切试验验证该本构模型的准确性。研究表明:在剪切变形过程中,金属橡胶接触对存在接触分离过程,接触点数量基本保持不变;无预加压缩荷载时,金属橡胶层状剪切本构模型与试验结果吻合良好,具有较高的准确性和精度,可以辅助金属橡胶层状微观分析。

According to the internal structure characteristics of the metallic rubber(MR) specimen as well as its mechanical properties, the shear constitutive model was divided into three parts: linear restoring force, coulombs friction force and nonlinear hysteresis force. The metallic rubber was firstly decomposed into several layers, combined with the statistical law of the contact-pair number of inner turn during the shear deformation process, the shear stiffness of the single contact-pair of the metallic rubber was deduced. Then, the expressions of mechanical components were obtained, and the layered shear constitutive model of MR was established. Finally, the accuracy of the constitutive model was verified through the shear experimental test of MR isolators. The results showed that during the shearing process, the metallic rubber contact pair had a contact-separation process, and the number of contact points remained basically unchanged. At the beginning of the unloading stage, the error between the experimental results and the numerical results was small. The layered shear constitutive model agreed well with the results of shear test without pre-compression load. It was shown that the constitutive model had high accuracy and precision, which could be used to assist the lamellar microanalysis of metallic rubber.