H16粉锻连杆的强度与疲劳分析
发布时间：2019-05-06 14:18
【摘要】：连杆是汽车发动机中重要的传动零部件之一,其质量对发动机的能量转换及汽车的行驶安全性有重要影响。粉锻连杆因其材料利用率高、机械力学性能好、锻件精度高、生产工序少、生产成本低等特点,具有良好的发展前景。连杆在工作过程中受力复杂,需要具有足够的强度与刚度。同时,连杆在周期性载荷的作用下,易产生疲劳失效,影响到发动机的正常工作。因此,需要开展粉锻连杆的强度及疲劳分析研究,保证粉锻连杆的使用可靠性。本文以某企业开发的粉锻连杆为研究对象,建立了连杆在发动机典型工况下的有限元模型和疲劳寿命预测模型,分析了连杆在典型工况下的应力分布,研究了影响连杆的疲劳寿命的因素,采用疲劳分析软件对连杆的疲劳寿命进行了预测,分析了连杆几何不对称因素对连杆强度及疲劳寿命的影响。基于有限元软件ABAQUS,建立了粉锻连杆组件的静态受力有限元分析模型,对连杆在三种典型工况下的受力情况进行了有限元分析,获得了连杆的应力分布与变形。对比了两种不同加载方式,即将载荷直接施加到活塞销上和将载荷直接施加到衬套上,对连杆应力分布的影响。根据有限元静态受力分析的结果,采用Fe-safe软件对粉锻连杆的疲劳寿命进行了分析和预测。对比了不同疲劳算法及平均应力修正方法对连杆疲劳寿命预测结果的影响,根据山东信义粉末冶金有限公司提供的粉锻连杆的疲劳失效样件的失效的形式、位置及最低疲劳寿命,确定了采用Stress-Based Brown-Miller算法和Morrow平均应力修正方法,来建立粉锻连杆疲劳寿命分析预测模型。研究了连杆表面粗糙度和材料强度对连杆疲劳寿命及疲劳安全系数的影响。针对粉锻连杆在实际锻造过程中可能出现的几何不对称的情况,建立了连杆几何不对称的有限元分析模型和疲劳寿命预测模型,分析了三种不同几何尺寸偏差对连杆的应力分布及变形量的影响,以及连杆几何不对称对连杆疲劳寿命及疲劳安全系数的影响。
[Abstract]:Connecting rod is one of the most important driving parts in automobile engine. Its quality has an important influence on the energy conversion of the engine and the driving safety of the automobile. Due to its high material utilization, good mechanical and mechanical properties, high precision of forging, less production process and low production cost, the powder forged connecting rod has a good prospect for development. The connecting rod needs to have enough strength and stiffness because of the complicated force in the working process. At the same time, under the action of periodic load, the connecting rod is prone to fatigue failure, which affects the normal work of the engine. Therefore, it is necessary to carry out the strength and fatigue analysis research of the powder forging connecting rod to ensure the reliability of the use of the powdered forging connecting rod. In this paper, the finite element model and fatigue life prediction model of the connecting rod under the typical working conditions of the engine are established, and the stress distribution of the connecting rod under the typical working condition is analyzed by taking the powder forging connecting rod developed by a certain enterprise as the research object. The factors that affect the fatigue life of the connecting rod are studied. The fatigue life of the connecting rod is predicted by using the fatigue analysis software. The influence of the geometrical asymmetry of the connecting rod on the strength and fatigue life of the connecting rod is analyzed. Based on the finite element software ABAQUS, the static force finite element analysis model of the powder forging connecting rod assembly is established. The stress distribution and deformation of the connecting rod are obtained through the finite element analysis of the stress condition of the connecting rod under three typical working conditions. The influence of two different loading modes on the stress distribution of the connecting rod is compared, that is, the load is directly applied to the piston pin and the load is directly applied to the bushing. According to the results of finite element static stress analysis, the fatigue life of powder forging connecting rod is analyzed and predicted by using Fe-safe software. The influence of different fatigue algorithm and average stress correction method on the fatigue life prediction of connecting rod is compared. According to the failure form of fatigue failure sample of powder forging connecting rod provided by Shandong Xinyi Powder Metallurgy Co., Ltd. The Stress-Based Brown-Miller algorithm and the Morrow mean stress correction method are used to establish the fatigue life analysis and prediction model of the powder forging connecting rod. The effects of surface roughness and material strength on fatigue life and fatigue safety factor of connecting rod were studied. The finite element analysis model and fatigue life prediction model of the connecting rod geometry asymmetry are established in view of the possible geometric asymmetry in the forging process of the powder forging rod. The effects of three different geometric size deviations on the stress distribution and deformation of the connecting rod and the influence of the geometrical asymmetry of the connecting rod on the fatigue life and the fatigue safety factor of the connecting rod are analyzed.
【学位授予单位】：山东大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U464.133.2;TG316
[Abstract]:Connecting rod is one of the most important driving parts in automobile engine. Its quality has an important influence on the energy conversion of the engine and the driving safety of the automobile. Due to its high material utilization, good mechanical and mechanical properties, high precision of forging, less production process and low production cost, the powder forged connecting rod has a good prospect for development. The connecting rod needs to have enough strength and stiffness because of the complicated force in the working process. At the same time, under the action of periodic load, the connecting rod is prone to fatigue failure, which affects the normal work of the engine. Therefore, it is necessary to carry out the strength and fatigue analysis research of the powder forging connecting rod to ensure the reliability of the use of the powdered forging connecting rod. In this paper, the finite element model and fatigue life prediction model of the connecting rod under the typical working conditions of the engine are established, and the stress distribution of the connecting rod under the typical working condition is analyzed by taking the powder forging connecting rod developed by a certain enterprise as the research object. The factors that affect the fatigue life of the connecting rod are studied. The fatigue life of the connecting rod is predicted by using the fatigue analysis software. The influence of the geometrical asymmetry of the connecting rod on the strength and fatigue life of the connecting rod is analyzed. Based on the finite element software ABAQUS, the static force finite element analysis model of the powder forging connecting rod assembly is established. The stress distribution and deformation of the connecting rod are obtained through the finite element analysis of the stress condition of the connecting rod under three typical working conditions. The influence of two different loading modes on the stress distribution of the connecting rod is compared, that is, the load is directly applied to the piston pin and the load is directly applied to the bushing. According to the results of finite element static stress analysis, the fatigue life of powder forging connecting rod is analyzed and predicted by using Fe-safe software. The influence of different fatigue algorithm and average stress correction method on the fatigue life prediction of connecting rod is compared. According to the failure form of fatigue failure sample of powder forging connecting rod provided by Shandong Xinyi Powder Metallurgy Co., Ltd. The Stress-Based Brown-Miller algorithm and the Morrow mean stress correction method are used to establish the fatigue life analysis and prediction model of the powder forging connecting rod. The effects of surface roughness and material strength on fatigue life and fatigue safety factor of connecting rod were studied. The finite element analysis model and fatigue life prediction model of the connecting rod geometry asymmetry are established in view of the possible geometric asymmetry in the forging process of the powder forging rod. The effects of three different geometric size deviations on the stress distribution and deformation of the connecting rod and the influence of the geometrical asymmetry of the connecting rod on the fatigue life and the fatigue safety factor of the connecting rod are analyzed.
【学位授予单位】：山东大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U464.133.2;TG316
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