外载荷作用下船舶推进系统非线性动力学分析

以某船推进系统为研究对象,应用有限元和子结构缩减法,建立了包含主机、轴系、螺旋桨及简易轴承座的船舶推进系统非线性多体动力学模型。对该系统在额定功率下燃气压力和螺旋桨激振力的作用进行了多体动力学计算。分析了螺旋桨、轴系等的受力情况及位移随曲轴转角的变化。结果表明,艉轴后轴承处轴系受力与位移呈现两端大中间小的分布情况,螺旋桨竖直向下位移最大值为2.86mm,轴向位移最大值为1.18mm,相对角位移最大值为0.087rad。该方法为分析和提高船舶推进系统可靠性及其优化等提供了重要参考。

Calculation and Analysis of Non-Linear Dynamics of Propulsion System with External Load

Ship propulsion system is investigated in this paper.A multi-body dynamics model of propulsion system including diesel engine,shaft,propeller and simple bearing blocks is established based on FE-models and substructure technique,where different bodies are coupled by several non-linear coupling elements.The calculation is performed when combustion pressure and propeller exciting force is loaded on corresponding bodies,and the dynamic behavior of shaft and propeller is investigated within a complete engine cycle.The results show that at the rear stern tube bearing the force and displacement of shaft at the two ends is much bigger than that in the middle.At the location of assembling the propeller,the maximum value of displacement is 2.86mm in vertical direction,and 1.18mm in axial direction,as well as the maximum relative angular displacement value is 0.087 rad.That provides an important reference for analyzing and improving the reliability of propulsion system and implementing its optimization.