摘要：A design of different microtextures on the surface of the crankpin bearing(CB)is proposed to ameliorate the lubrication and friction performance(LFP)of *** the basis of the CB s hydrodynamic lubrication model,the bearing surface of CB using different microtextures,such as wedge-shaped textures(WSTs),square textures(STs),circular textures(CTs),and combined square-circular textures(CSCTs),is simulated and assessed under various external loads of the CB at an engine speed of 2000 r/*** pressure of the oil film,the frictional force,the force of the solid asperity contact,and the friction coefficient of the CB are used as objective *** indicate that the bearing surface designed by the STs remarkably improves the CB s LFP in comparison with other structures of WSTs,CTs,and ***,the average values of the frictional force,solid asperity contact,and friction coefficient of the CB using the STs are greatly reduced by 28.5%,14.5%,and 33.2%and by 34.4%,26.3%,and 43.6%in comparison with the optimized CB dimensions and CTs,***,the application of the STs on the CB surfaces can enhance the LFP of engines.

摘要：结合大学生工程训练综合能力竞赛S组项目提出的隔桩变距要求,设计开发了一种基于空间四连杆(RSSR)机构控制转向的变距行走无碳小车。通过建立转向机构优化模型,利用MATLAB仿真优化了空间四连杆机构参数。针对因结构微调带来小车发车姿态变化的问题,对小车关键部件进行了定位设计,并通过制作小车实物模型,验证了可行性,为无碳小车优化设计提供了参考。

摘要：U型波纹管是常用的管道连接和补偿装置,波纹管的结构设计对其声学传递特性具有重要影响。采用声学有限元法建立了波纹管的数值计算模型,计算了不同结构参数下波纹管的声学传递损失,得到了结构参数对波纹管声学传递损失的影响规律。基于有限元仿真结果,建立了波纹管传递损失峰值频带上、下限频率计算的数学模型。设计加工了一个波纹管试件,采用两负载实验法测试了其声学传递损失,并将实验结果与有限元仿真结果进行了对比。结果表明:U型波纹管的声学传递损失具有典型的带阻滤波特性;波高、波宽及内径是影响波纹管传递损失峰值频带上、下限频率的最主要因素;波纹管传递损失峰值频带上、下限频率数学模型的计算结果与有限元仿真结果的误差在±3.0%以内;波纹管声学传递损失的实验结果与仿真结果基本吻合,验证了波纹管声学有限元模型和声学传递损失峰值频带上、下限频率数学模型的准确性与有效性。该研究为U型波纹管的声学设计提供相应的理论依据,也为其声学应用提供了新思路。