基于三维有限元模型的轴系校中

Shaft line alignment based on three-dimensional FE model

船舶推进系统设计中,轴系校中计算通常的做法是将轴系看成一维梁模型,且不考虑船体的作用,计算结果与实际有较大差别.用三维模型对船体、轴承及轴承油膜的刚度进行了有限元分析.在三维曲轴模型中考虑了每个气缸的旋转和摆动质量、主轴承的刚度和推力轴承的刚度等,考虑了轴承间隙等非线性因素,以及船体弯曲变形、轴承温度变化、桨轴向推力偏心及推力轴承反力偏心引起的动态弯矩等因素,计算结果更符合实际.

Proper shaft line alignment is one of the most important actions during the design of the propulsion system.Usually,one dimensional beam model of the shaft system is isolated from the ship hull.The stiffness of the ship,bearing and oil film were calculated by a three-dimensional FE model in this paper.The crankshaft element was created based on crank elements.Some properties were considered,including rotating and oscillating mass for each cylinder,main bearing stiffness and thrust bearing stiffness,bearing clearance,ship construction flexibility and deformations,bearing thermal deformation,bending moment that acts on propeller shaft and thrust shaft.Achieving a more accuracy result is possible by the mentioned method.