装载机工作装置的动力学仿真与有限元分析

发布时间：2018-09-05 16:09

【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。
[Abstract]:The strength and rigidity of the loader's working device are the important factors that directly affect the reliability and life of the whole machine, so its structure design has become one of the important contents of the overall design of the loader. Taking the working device of a loader as an example, this paper studies its motion, dynamic simulation and finite element analysis, and finds out the maximum force of the working device, that is, the eccentric loading mode. The distribution area of dangerous stress concentration under ground excavating condition is used as the theoretical basis to improve the structure of the working device, thus obtaining a more reliable structure. Perfect structural design scheme. (1) the working device of loader is digitally modeled and assembled by three-dimensional modeling software Pro/ENGINEER, and assembly animation is made and derived. (2) the working condition of the working device of loader is carried out. The external load analysis and calculation show that the insert resistance is 245391.81N, the excavating resistance is 361464.88N, the insertion resistance is 101039.57N and the excavating resistance is 148838.48Nunder the eccentric loading mode. The virtual prototype model of the working device is established by using the ADAMS simulation software, and then the motion, dynamics simulation and analysis of each operation step are carried out, and the motion and dynamics simulation animation are derived. The results show that in the working process of the bucket after 5 seconds, the lifting force of the rotary cylinder of the working device is always greater than that of the lifting cylinder, and the tipping will not occur, and under the condition of eccentricity external load, the force value of the working device component system is larger than that of the lifting oil cylinder. Under the condition of ground shovel, the force of each hinge point is the largest; the eccentric loading mode and the ground excavating condition are selected as the research objects in the finite element analysis plate; in the simulation result data, The maximum force acting on the lower hinge of the arm is close to 1500kN. (3) the simplified mechanical model of the moving member is established, and the mechanical analysis and calculation of the components of the working device are carried out by means of the mechanical calculation method. The stress value of each member is obtained under the condition of maximum force. From the results, the maximum force value of the lower hinge point of the arm is 1510.3kN, which is equivalent to the 1500kN result of the simulation results. The finite element static analysis of moving arm frame is carried out by using ANSYS finite element analysis software. It is obtained that the distribution of dangerous stress concentration occurs in the upper and lower parts of the eccentric side of the moving arm plate and in the inner surface of the hinge of the lift cylinder. The stress range is 632.32MPa-948.37MPa, and the stress value on the boundary position and support part of the frame beam has exceeded the yield limit of 345MPa, which is prone to fracture. The maximum displacement occurs at the lower hinge on the side of the large eccentric load, and the maximum deformation is 17.531 mm. (4) according to the results of the finite element analysis, an improved design scheme for the structure of the movable arm frame is proposed. The improved structure is analyzed again by finite element method. The results show that, in the improved structure, the maximum deformation at the lower hinge point of the front end of the arm plate is reduced to 11.9 mm, and the dangerous area of stress concentration in the upper and lower parts of the plate is obviously reduced. The stress value is reduced to 316.3MPa-623MPa, and the danger point of the welding position between the beam and the moving arm plate is completely disappeared, which verifies the rationality of the structural improvement design.
【学位授予单位】：西北农林科技大学
【学位级别】：硕士
【学位授予年份】：2011
【分类号】：TH243

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