基于有限元法的农用车辆发动机连杆动静态特性分析

Dynamic and Static Characteristics of Connecting Rods in Agricultural Vehicle Engines Based on Finite Element Method

连杆是农业车辆发动机的重要组成部分。由于农业车辆作业强度大,连杆作业过程中其结构、位移及应力变化严重影响作业性能。针对以上问题,本文以某厂生产的内燃机连杆为研究对象,利用三维建模软件NX10.0建立连杆组模型,采用有限元法对连杆杆身、大头轴瓦、小头衬套进行受力分析,并对连杆在自由模态和预应力模态下的动态特性进行了分析。结果表明:连杆受拉伸载荷时最大应力为199 MPa,受压缩载荷时最大应力为230 MPa,且杆身两侧会发生翘曲变形,最大变形量为0.03 mm;在相同的接触条件和约束条件下,自由模态下前10阶振型和预应力下前6阶振型的变形总是在大(小)头处、杆身与两端的过渡处、杆身的中间部位。

The connecting rod is an important component of agricultural vehicle engines.Due to the high intensity of agricultural vehicle operation,the changes in structure,displacement and stress of connecting rods during operation seriously affect the operational performance.In response to the above issues,this paper took the internal combustion engine connecting rod produced by a certain factory as the research object,used 3D modeling software NX10.0 to establish a connecting rod group model,used finite element method to analyze the force on the connecting rod body,large end bearing shells and small end bushings,and analyzed the dynamic characteristics of the connecting rod under free mode and prestressed mode.The results showed that the maximum stress of connecting rod under tensile load was 199 MPa,and the maximum stress under compressive load was 230 MPa,warping deformation occured on both sides of the rod,with a maximum deformation of 0.03 mm;under the same contact and constraint conditions,the deformation of the first 10 modes of vibration in free mode and the first 6 modes of vibration in prestressed mode always occured at the large(small)ends,the transition between the rod body and both ends,and the middle part of the rod body.