静载荷作用下金属橡胶失效判据及耐久性试验

金属橡胶(MR)材料由于其出色的阻尼性能广泛应用在各种减振、隔振、抗冲击结构系统中,掌握其失效判据和准确预测其耐久性是关系到整个系统能否安全可靠工作的重要问题。针对MR构件在静载荷持续作用下的失效判据和耐久性展开了试验研究。结果表明:从结构尺寸变化量和力学性能蜕变量2个方面定义MR的失效判定参数合理可行,通过确定阈值可判定MR是否失效并给定耐久寿命。随保载时间的增加,MR的失效评定参数(结构尺寸变化量和力学性能蜕变量)呈现明显的阶段性变化,能分别反映MR材料内部微观结构及受力状态随持续静载荷的变化。在本试验中,无论保载载荷大小,MR结构在总试验时间未表现出结构尺寸失效。而MR保载载荷的增大会显著削弱其力学性能耐久寿命,导致割线模量蜕变量过大,MR构件表现出力学性能的明显失效。

Failure criterion and durability characteristics of metal rubber under static compression load

Metal rubber(MR) is widely applied in vibration control, vibration isolation and shock resistance areas because of its characteristics of elasticity, damping, reliability and adaptation to the operational environment. It is critical for the system safety to accurately define the failure criterion and forecast the failure of MR in engineering. The failure criterion and durability property of MR under long-term static compression load were studied through the experimental method. The result shows that it is feasible to determine the MR failure by the structure deforming factor and mechanical property decaying factor, besides, the failure status and durability life can be determined by confirming the thresholds of these factors. The failure criterion factors of MR shows multi-stage property varying with loading time,denoting the change of MR inner micro structure and forced state with continuous loading time. In the test result of this paper, the metal rubber specimens exhibit no deforming failure under different static load status. However, under larger static load condition, the durability life of MR can be greatly decreased, resulting in excessively large tangent modulus decaying factor and obvious failure of MR mechanical properties.