推进轴系橡胶艉轴承刚度等效研究

Equivalent Stiffness of the Rubber Stern Bearing of a Propulsion Shafting System

研究推进轴系橡胶艉轴承刚度等效方法,给出重力作用下的轴系艉轴承的等效支承位置及刚度。建立转轴-轴承非线性接触有限元模型,获得轴承表面压力和位移分布,然后采用单点、多点支承模型进行刚度等效。结果表明,单点支承等效可以较为准确地描述转轴位移,但转角不够准确;5点支承等效较单点支承等效具有更高的精度,可以较为准确地描述轴系变形,而且动刚度等效也能较准确地描述频响特性(微幅振动条件下),尤其对于低频区域(小于60 Hz),与转轴-轴承接触模型的计算结果几乎一致。

The equivalent stiffness of the rubber stern bearing of a propulsion shafting system is studied and a method for computing the equivalent stiffness and support positions is proposed.A non-linear contact FEM model of the shaftbearing system is built to calculate the surface pressure and displacement distribution of the bearing.Two models associated with the single-support and multi-support are employed respectively to obtain the equivalent stiffness.The results show that the single-support model is comparatively accurate for computing the displacement of the shaft but less accurate for the rotation angle.Compared with the single-support model,the multi-support model is able to describe the deformation of the shaft in higher accuracy and the equivalent dynamic stiffness can result in accurate frequency response characteristics.Particularly at low frequencies(below 60 Hz),the responses are nearly the same as that of the shaft-bearing model.