装载机驱动桥壳疲劳寿命预测研究
发布时间：2019-01-26 07:23
【摘要】：驱动桥壳作为装载机的关键零部件,承受来自路面和装载机本身的各种冲击和作用力,其刚度和强度对于主减速器和差速器齿轮的正常啮合及半轴的正常工作有着重要意义。装载机的作业工况复杂,驱动桥壳所承受的外部载荷是随时间而变化的动态随机载荷。因此,桥壳的主要破坏形式是交变载荷作用下损伤长期积累而导致的疲劳失效。本文结合浙江省科技厅重大科技专项项目(2009C11111)“轮式装载机驱动桥关键技术研究与产业化”,对ZL50型装载机驱动桥壳进行了疲劳寿命预测研究。本文的主要研究内容如下: 1)利用大型建模软件UG建立了桥壳三维实体模型,将该几何模型导入前处理软件HyperMesh中进行网格划分,最终得到桥壳的有限元分析模型。利用ABAQUS对桥壳在台架试验载荷和装载机满载工况下分别进行了强度有限元分析,获得了桥壳的应力分布。通过在桥壳表面覆盖一层很薄的壳单元,为后续的疲劳分析提供了更为准确的桥壳表面应力。通过比较桥壳台架疲劳试验加载频率和模态分析获得的桥壳固有频率,说明了后续章节采用准静态疲劳分析法估算桥壳寿命的合理性。 2)根据桥壳强度有限元分析结果,确定了桥壳载荷谱的测试方案,测取了桥壳的载荷-时间历程。对采集到的载荷数据进行了较详细的分析,利用nSoft软件的数据处理模块,对测试数据进行了雨流计数处理,得到了各采样测点应力-时间历程的雨流/损伤直方图和损伤时间历程。 3)分别基于有限元法和实测应力,结合材料的疲劳特性(S-N曲线),选用Miner累积损伤法则,利用nSoft软件中的疲劳分析模块,对桥壳进行了疲劳寿命预估,得到了驱动桥壳疲劳寿命云图及最低疲劳寿命。 4)为了考察焊缝对桥壳疲劳强度的影响,在桥壳整体疲劳损伤/寿命分析的基础上,进行了焊缝局部细节的疲劳分析。应用BS7608标准,分别基于实测应力和有限元法进行了焊缝疲劳寿命预估研究。两种计算结果均表明,焊缝的疲劳强度明显的低于母材的疲劳强度,这和焊接结构的疲劳强度通常取决于焊缝接头疲劳强度的实际情况是相吻合的。 本文对装载机驱动桥壳的载荷谱测试及疲劳寿命研究方法也为其它车辆机械零部件的抗疲劳设计提供了参考,本文的研究工作具有实用意义和推广价值。
[Abstract]:As the key parts of the loader, the drive axle housing bears all kinds of impact and force from the road surface and the loader itself. Its stiffness and strength are of great significance to the normal meshing of the main reducer and differential gear and the normal work of the half shaft. The working condition of the loader is complex, and the external load of the drive axle housing is a dynamic random load varying with time. Therefore, the main failure form of bridge shell is fatigue failure caused by long-term accumulation of damage under alternating load. In this paper, the fatigue life prediction of the driving axle housing of the ZL50 loader is studied based on the "key Technology Research and industrialization of the Wheel Loader Drive Axle" (2009C11111) of Zhejiang Science and Technology Department. The main contents of this paper are as follows: 1) the three-dimensional solid model of the bridge shell is established by using the large-scale modeling software UG. The geometric model is imported into the pre-processing software HyperMesh for mesh division, and finally the finite element analysis model of the bridge shell is obtained. The strength finite element analysis of the bridge shell under the load of bench test and full load of loader was carried out by ABAQUS, and the stress distribution of the shell was obtained. By covering a thin shell element on the surface of the bridge shell, it provides a more accurate surface stress for the subsequent fatigue analysis. By comparing the loading frequency of bridge shell fatigue test and the natural frequency of bridge shell obtained by modal analysis, the rationality of using quasi static fatigue analysis method to estimate bridge shell life is explained in the following chapters. 2) according to the results of the finite element analysis of the bridge shell strength, the test scheme of the load spectrum of the bridge shell is determined, and the load-time history of the bridge shell is measured. The load data collected is analyzed in detail, and the rain flow count is processed by using the data processing module of nSoft software. The rain flow / damage histogram and damage time history of the stress-time history of each sampling point are obtained. 3) based on the finite element method and the measured stress, combined with the fatigue characteristics of the material (S-N curve), the fatigue life of the bridge shell is predicted by using the fatigue analysis module of nSoft software and the Miner cumulative damage rule. The fatigue life cloud diagram and the minimum fatigue life of the drive axle shell are obtained. 4) in order to investigate the effect of welding seam on fatigue strength of bridge shell, fatigue analysis of welding seam is carried out on the basis of fatigue damage / life analysis of bridge shell. The fatigue life prediction of weld is studied by BS7608 standard based on measured stress and finite element method. The results show that the fatigue strength of weld is obviously lower than that of base metal, which is consistent with the fact that the fatigue strength of welded structure usually depends on the fatigue strength of weld joint. This paper provides a reference for the load spectrum test and fatigue life research of the driving axle housing of the loader. The research work in this paper is of practical significance and popularization value for the anti-fatigue design of other vehicle mechanical parts.
【学位授予单位】：浙江理工大学
【学位级别】：硕士
【学位授予年份】：2011
【分类号】：TH243
本文编号：2415255
[Abstract]:As the key parts of the loader, the drive axle housing bears all kinds of impact and force from the road surface and the loader itself. Its stiffness and strength are of great significance to the normal meshing of the main reducer and differential gear and the normal work of the half shaft. The working condition of the loader is complex, and the external load of the drive axle housing is a dynamic random load varying with time. Therefore, the main failure form of bridge shell is fatigue failure caused by long-term accumulation of damage under alternating load. In this paper, the fatigue life prediction of the driving axle housing of the ZL50 loader is studied based on the "key Technology Research and industrialization of the Wheel Loader Drive Axle" (2009C11111) of Zhejiang Science and Technology Department. The main contents of this paper are as follows: 1) the three-dimensional solid model of the bridge shell is established by using the large-scale modeling software UG. The geometric model is imported into the pre-processing software HyperMesh for mesh division, and finally the finite element analysis model of the bridge shell is obtained. The strength finite element analysis of the bridge shell under the load of bench test and full load of loader was carried out by ABAQUS, and the stress distribution of the shell was obtained. By covering a thin shell element on the surface of the bridge shell, it provides a more accurate surface stress for the subsequent fatigue analysis. By comparing the loading frequency of bridge shell fatigue test and the natural frequency of bridge shell obtained by modal analysis, the rationality of using quasi static fatigue analysis method to estimate bridge shell life is explained in the following chapters. 2) according to the results of the finite element analysis of the bridge shell strength, the test scheme of the load spectrum of the bridge shell is determined, and the load-time history of the bridge shell is measured. The load data collected is analyzed in detail, and the rain flow count is processed by using the data processing module of nSoft software. The rain flow / damage histogram and damage time history of the stress-time history of each sampling point are obtained. 3) based on the finite element method and the measured stress, combined with the fatigue characteristics of the material (S-N curve), the fatigue life of the bridge shell is predicted by using the fatigue analysis module of nSoft software and the Miner cumulative damage rule. The fatigue life cloud diagram and the minimum fatigue life of the drive axle shell are obtained. 4) in order to investigate the effect of welding seam on fatigue strength of bridge shell, fatigue analysis of welding seam is carried out on the basis of fatigue damage / life analysis of bridge shell. The fatigue life prediction of weld is studied by BS7608 standard based on measured stress and finite element method. The results show that the fatigue strength of weld is obviously lower than that of base metal, which is consistent with the fact that the fatigue strength of welded structure usually depends on the fatigue strength of weld joint. This paper provides a reference for the load spectrum test and fatigue life research of the driving axle housing of the loader. The research work in this paper is of practical significance and popularization value for the anti-fatigue design of other vehicle mechanical parts.
【学位授予单位】：浙江理工大学
【学位级别】：硕士
【学位授予年份】：2011
【分类号】：TH243
【引证文献】
相关硕士学位论文 前1条
1 韩龙海;载重车驱动桥总成动态特性分析研究[D];青岛理工大学;2013年
，本文编号：2415255
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