【作者】 李凯；

【导师】 朱瑞祥；

【作者基本信息】 西北农林科技大学 ， 农业机械化工程， 2011， 硕士

【摘要】 装载机工作装置的强度、刚度等是直接影响整机产品使用可靠性及寿命等性能的重要因素,故其结构设计便成为装载机整体设计的重要内容之一。本文以某装载机机型的工作装置为例,对其进行了运动、动力仿真与有限元分析研究,找出了工作装置在最大受力情况,即偏心加载方式、地面铲掘工况下的危险应力集中分布区域,并以此作为理论依据,对工作装置进行了结构形式改进,从而得到了更加可靠、完善的结构设计方案。(1)通过三维造型软件Pro/ENGINEER对装载机工作装置进行了数字化建模并装配,制作并导出了装配动画。(2)对装载机工作装置进行了作业工况、外载荷分析与计算,得到对称加载方式时插入阻力245391.81N,铲掘阻力361464.88N;偏心加载方式时插入阻力101039.57N,铲掘阻力148838.48N。采用ADAMS仿真软件建立了工作装置的虚拟样机模型,进而进行了各个作业步骤的运动、动力学仿真与分析,并导出了运动、动力学仿真动画。结果显示:铲斗在第5秒后的工作过程中,工作装置的转斗油缸掘起力总大于举升油缸掘起力,不会发生倾翻;在偏心外载荷工况下,工作装置构件系统所受的力值较大;在地面铲掘工况下,各铰点所受的力值最大;将偏心加载方式和地面铲掘工况选作有限元分析板块中的研究对象;在仿真结果数据中,动臂下铰点所受力的最大值接近1500kN。(3)建立了简化运动构件力学模型,通过力学计算方法,对工作装置各构件进行了受力分析计算,得出在最大受力情况下各构件的受力数值。从结果中得到,动臂下铰点最大受力值为1510.3kN,与仿真结果1500kN结果相当。应用ANSYS有限元分析软件,对动臂框架进行有限元静力分析。得到危险应力集中分布区域发生在受偏载一侧动臂板较前端的上下部分以及与举升缸铰孔铰接的内表面处,应力范围值632.32MPa-948.37MPa;动臂框架横梁与动臂板接壤位置和支撑部位上存在的应力值也已超出了屈服极限345MPa,此位置容易发生断裂。最大位移变形发生在受偏心载荷较大一侧的下铰点处,最大变形量为17.531mm。(4)根据有限元分析结果,提出了动臂框架结构形式改进的设计方案,并对改进后的结构进行了再次有限元分析。结果显示,在改进后的结构中,动臂板前端下铰点处的最大变形量缩小为11.9mm;动臂板上下部的应力集中危险区域明显减小,应力值降低到了316.3MPa-623MPa;横梁与动臂板焊接部位的危险点完全消失,验证了结构改进设计的合理性。更多还原

【Abstract】 The loader working device’s intensity and stiffness properties directly affect the use reliability and life of the whole products, so the structure design will become the important content of loader integral design. The loader working device is taken as the research object in the thesis to study its kinematic and dynamic simulation and finite element stress analysis, to identify the distribution area of dangerous stress, namely the eccentric loading and ground condition shovel position. Taking it as a theoretical basis to make the structural design of working device in order to get a more reliable and comprehensive program of structural improvements.(1)Model and assemble the loader working device by using three-dimensional modeling software Pro/E, and then got and exported assembly animation.(2)Analysis the loader working condition and the loading manners of external load, and the result is: The insert resistance 245391.81N and shovel dug resistance 361464.88N when symmetric loading; The insert resistance 101039.57N and shovel dug resistance 148838.48N when eccentric loading. After establishing loader working device virtual prototyping model by ADAMS simulation software, did the dynamic simulation and analysis of each operating movement of the device, and then exported the dynamic simulation animation. The results showed: After the work of taking back the bucket, the rise force of turn fights oil cylinder was always more than arm oil cylinder’s, which showed it won’t happen poured over; In the eccentric loading method, the force of the device system was bigger; Every hinge point borne the maximum force value at the ground shovel dug conditions; so the thesis chosen the eccentric loading method ground and shovel dug conditions as research object in finite element analysis drafts. In the simulation results data, the maximum stress of below arm hinge point approximates 1500kN.(3)Established a simple dynamics structural model. Through the calculation method of the mechanics of materials, every component of device was calculated so as to get load numerical of the maximum stress condition. From the results: the maximum stress value of below hinge point arm is 1510.3kN, which was close to the simulation calculation 1500 kN. Using the finite element resolution software, we analysed the arm framework with finite element method, and found the dangerous stress concentrated in upper and lower parts of arm board which was slanting load and the inside surface of reaming joint, stress range between 948.37 MPa and 632.32 MPa. The stress of welding parts between beam and arm board had exceeded yield limits(345MPa), this position easily happens fracture. The maximal deformation was lower hinge point whose eccentric loading force was larger ,and the maximum deformation was 17.531 mm.(4)According to the results of finite element analysis, the thesis put forward improved modification scheme of arm framework structure and did the finite element analysis on the improved structure. The results showed: In the improved structure, the maximal deformation of the below arm board hinge point shrunked to 11.9 mm; The dangerous stress concentration areas of the upper and lower parts of arm board decreased obviously, and stress range drop to 316.3 MPa - 623MPa;The stress of welding parts between beam and arm board completely disappeared.更多还原