基于单自由度弹簧阻尼器模型和Mindlin理论模型,通过金属材料干摩擦动态特性实验,得到了干摩擦迟滞特性曲线以及等效刚度与等效阻尼变化规律.随着两接触面间相对位移幅值的增大,摩擦力等效刚度单调下降,并且趋于平缓,而摩擦力等效阻尼则随位移幅值的增大而单调上升,并且在无量纲相对位移幅值为2.0附近达到最大值后随位移幅值的增大而单调下降.通过比较分析实验数据和两种理论模型的计算结果发现,当无量纲相对位移幅值小于1.0时理论模型无法反映系统的刚度与阻尼特性.利用有限元分析软件MARC建立了与实验相一致的有限元预测模型.对比分析表明,有限元模拟结果与实验结果具有较好的吻合程度,有限元方法可以帮助分析工程实际中金属材料的干摩擦特性.
A single-degree-of-freedom spring damper model and a Mindlin theoretical model were analyzed and a test-bed for metal's dry friction characteristics was built to gain the hysteresis curve, equivalent stiffness and equivalent damp. With the growing of the amplitude of relative displacement between interfaces, the equivalent stiffness of the friction force descends and the descending trend becomes gentle; while the equivalent damp of the friction force ascends and gets its peak when the nondimensional relative displacement amplitude equals to 2.0, then it descends with the increasing displacement amplitude. The compari- son between the test and theoretical data indicates that when the nondimensional relative displacement amplitude is less than 1.0, the theory model cannot describe the system's stiffness and damping characteristics. A corresponding FEM model was built in MARC. The consistency between the results of the FEM model and test data validates the FEM prediction method, which can help analyze the real material's dry friction characteristics.