连杆结构分析及其性能优化设计的研究

发布时间：2019-03-12 11:20

【摘要】：本文的目的是根据生产过程中的实际运行工况参数,对小型通用汽油机连杆组件进行优化设计,尽可能达到质量较轻、体积较小,外形布局合理,最大程度缓解连杆大、小头与杆身过渡区的应力集中现象。运用CATIA V5实现小型通用汽油机连杆的参数化三维实体特征建模,并进行了有限元分析。由于CATIA是CAD/CAE一体化的设计与分析平台,这样就不存在实体模型向有限元模型转化过程中数据丢失、特征损坏等现象。运用CATIA V5在对连杆组件进行有限元分析时,采用了刚性约束(即曲柄销约束),模拟了连杆大头孔与曲柄销之间的接触状态。考虑了单元尺寸、单元类型对网格质量的影响。通过CATIA CAE对小型通用汽油机的连杆进行结构强度及刚度变形分析和动态性能分析。可以在设计过程中边进行设计边进行分析,使分析的数据结果充分地反映到设计上来,真正体现CAE为实际生产服务。在优化约束的条件下,连杆的结构尺寸发生了变化,使应力与变形有所增大,但此时的安全系数为1.55,大于材料的最低安全系数1.5。同时大小端过渡圆弧的优化减缓了连杆过渡圆弧处的应力集中现象,使连杆的结构更加合理。另外,优化前后连杆的质量减少大约7%,所以连杆的惯性力也有一定程度的减小,并对改善小型通用汽油机的振动及噪声有一定的帮助。
[Abstract]:The purpose of this paper is to optimize the connecting rod assembly of a small general gasoline engine according to the actual operating condition parameters in the production process, so as to achieve the lighter weight, smaller volume, reasonable shape layout and maximum ease of connecting rod as much as possible. Stress concentration phenomenon in the transition zone between small head and rod body. The parametric three-dimensional solid feature modeling of the connecting rod of a small general gasoline engine is realized by using CATIA V5, and the finite element analysis is carried out. Because CATIA is an integrated design and analysis platform of CAD/CAE, there is no data loss and feature damage in the process of transformation from entity model to finite element model. In the finite element analysis of connecting rod assembly with CATIA V5, the rigid constraint (that is, crank pin constraint) is used to simulate the contact state between the hole of connecting rod and the crank pin. The influence of element size and cell type on mesh quality is considered. The structural strength, stiffness and deformation analysis and dynamic performance analysis of the connecting rod of a small general purpose gasoline engine are carried out by means of CATIA CAE. In the process of design, the analysis can be carried out while designing, so that the results of the analysis can be fully reflected in the design, and the CAE can really serve for the actual production. Under the condition of optimal constraint, the structural dimension of the connecting rod changes, which increases the stress and deformation, but the safety factor is 1.55, which is greater than the minimum safety factor of 1.5. At the same time, the optimization of the transition arc at the end of the connecting rod reduces the stress concentration phenomenon at the transition arc of the connecting rod and makes the structure of the connecting rod more reasonable. In addition, the mass of the connecting rod before and after optimization is reduced by about 7%, so the inertia force of the connecting rod also decreases to a certain extent, and it is helpful to improve the vibration and noise of the small-scale general purpose gasoline engine.
【学位授予单位】：天津大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TK413.32

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