隔振系统中垫片表面工艺质量与法向接触刚度的关系

Relationship Between the Gasket Surface Roughness and its Normal Contact Stiffness in Isolation Systems

安装船舶隔振系统时,由于不同隔振器实际承载和变形量的偏差,需要使用垫片来调整安装间隙。而已有研究表明,隔振系统中垫片的表面工艺质量与法向接触刚度有关联。基于分形接触理论,分析推导垫片法向接触刚度与材料属性、表面工艺质量的关系式,结合表面粗糙度与分形参数的关系,提出一种利用表面工艺质量参数(如粗糙度、粘合率等)估算垫片法向接触刚度的方法。数值计算结果表明:垫片法向接触刚度随表面粗糙度值的减小和粘合率的增大而增大,且粘合率的影响相对较大;当粘合率一定时,法向接触刚度在Ra3 6.3μm时变化较小,而在Ra￡6.3μm时变化较大;综合考虑垫片加工水平、加工成本以及接触面对系统的影响,建议垫片表面加工精度取Ra=6.3μm为宜。

Gaskets are often used to adjust the clearance during the installation of ship isolation systems, since the system may suffer from geometric dimension deviation. It has been also verified that the surface process quality of gaskets is closely related to its normal contact stiffness. In this paper, the exact relation is investigated between the normal contact stiffness of gasket surfaces and the gasket material properties as well as the fractal parameters, based on the fractal theory. A new method to estimate the normal contact stiffness is then proposed. The numerical results show that the contact stiffness increases as the value of surface roughness decreases or when the adhesion rate increases. Particularly, the adhesion rate plays a more important role when determining the contact stiffness. However, if the adhesion rate is fixed, little changes can be observed in the contact stiffness when Ra ≥ 6.3 μm , while the change becomes relatively significant when Ra ≤ 6.3 μm. Thus, a balanced value of Ra = 6.3 μm is suggested for the practical surface roughness, considering the cost of surface processing and the effects of the contact stiffness on the overall system performance.