金属橡胶非成形方向迟滞特性力学模型研究

Research on Mechanical Model of Metal Rubber for Hysteresis Characteristic in the Non-forming Direction

金属橡胶是一种各向异性材料,其非成形方向与成形方向的力学特性存在显著不同。依据金属橡胶非成形方向变形的主要特征,对金属丝螺旋卷的空间位形、接触模式进行分析,揭示金属橡胶非成形方向变形的细观物理机制。结合螺旋卷的弹性变形特征和金属橡胶内部摩擦力接触点分布规律,建立金属橡胶非成形方向的力学模型,实现不同预变形下金属橡胶加载和卸载过程迟滞力学特性的预测。该模型包含金属丝直径和弹性模量、螺旋卷直径、材料相对密度等基本的材料结构参数,从理论上解释金属橡胶非成形方向的弹性特性和多点接触的干摩擦特性产生的机理。通过不同相对密度的金属橡胶试件对所建模型进行试验验证,发现理论计算和试验结果有较好的一致性,为分析和预测金属橡胶非成形方向的刚度和阻尼提供理论依据。

Metal rubber is a kind of anisotropic material, and its mechanical properties in the non-forming direction are significantly different from those in the forming direction. According to the main deformation characteristic of metal rubber in the non-forming direction, the configuration and contact mode of wire helixes are analyzed to reveal the mesoscopic physical mechanism of its non-forming direction. Combined with the elastic deformation characteristic of wire helixes and the regularity of distribution of frictional contact points, a mechanical model of the non-forming direction of metal rubber is established, which can describe the hysteresis characteristic of its loading and unloading process under different pre-deformation. In the model the basic structural parameters of metal rubber are included which are the diameter and elastic modulus of wire, the diameter of wire helix, the relative density of material, and so on, so it is easy to explain the physical nature of the elastic characteristic and the damping characteristic of dry friction of multipoint contact of metal rubber in the non-forming direction. The experiments on metal rubber specimens with different relative densities are carried out to verify the theory model. The results show that the theoretic calculations are consistent with the experimental data. It provides the theoretical basis for studying and predicting the stiffness and damping of the non-forming direction of metal rubber.