轮式装载机前车架的有限元分析

发布时间：2018-04-18 00:23

本文选题：前车架 + 运动学仿真　；参考：《西北农林科技大学》2011年硕士论文

【摘要】：轮式装载机是一种用途较广的工程机械,主要对散料进行铲装,通常是在露天矿山或工程建设工地作业,工作环境恶劣、复杂,在作业过程中结构件容易发生破坏失效。前车架作为装载机支撑工作装置的基础件,其铰接点的布局是否合理,会影响到工作装置的工作性能。在作业过程中前车架会承受工作装置传来的载荷,在颠簸的路面行驶或者作业时,还会受到剧烈的冲击载荷,容易发生破坏失效。所以在设计之初对工作装置及前车架进行运动学和动力学仿真、对前车架进行强度分析显得尤为重要。本文运用三维软件Pro/E建立装载机工作装置及前车架的三维模型,应用现代设计方法中的虚拟样机技术和有限元分析方法来对其进行研究。首先对装载机作业过程中的受力情况进行分析,然后在多体动力学软件ADAMS中建立虚拟样机模型,对其进行了运动学和动力学仿真。运动学仿真主要分析工作过程中工作装置各构件是否会发生干涉,得到其最大卸载高度以及运动轨迹等;动力学仿真则分为对称载荷和偏载两种不同情况,模拟装载机连续、复合作业动作,得到了前车架与工作装置各铰接点的受力变化曲线,进而为前车架的有限元分析提供基础数据。再将前车架几何模型导入到有限元分析软件ANSYS中,建立有限元分析模型,根据装载机作业过程中几种典型工况,从动力学仿真结果中读取前车架各铰接点对应的受力,并以此作为载荷,对前车架进行静强度分析,得到前车架在不同工况下的应力云图和位移云图。根据静强度分析结果,确定了前车架结构中存在的危险点,进而对其进行局部结构的优化改进,并分析了优化结果的合理性。从得到的位移云图和应力云图可以看出,前车架结构的最大位移和应力均明显的减小:正载、最大起掘力铲掘工况下,最大应力值从优化前的420Mpa降低到273Mpa,最大位移从1.568mm减少到1.158mm;偏载、最大牵引力水平插入工况下,最大应力值从优化前的530Mpa降低到264Mpa,最大位移从2.684mm减少到1.979mm;偏载、最大起掘力铲掘工况下,最大应力值从503Mpa降低到了307Mpa,最大位移从1.956mm减少到1.452mm。分析结果表明,结构优化后前车架的应力和应变的分布更为合理。对前车架进行了模态分析,得到其固有频率和固有振型,结合分析计算的轮式装载机外部激振源的激振频率,为前车架的进一步优化设计和设计减振装置提供依据。通过对轮式装载机工作装置的虚拟仿真以及对前车架的有限元分析,为轮式装载机的工作装置及前车架的结构设计提供了理论支持。
[Abstract]:Wheel loader is a kind of widely used construction machinery. It mainly shovels the bulk materials, usually in open pit mines or engineering construction sites. The working environment is bad and complex, and the structural parts are prone to damage and failure in the process of operation.The front frame is the base part of the loader supporting working device, whether the layout of the hinge point is reasonable or not will affect the working performance of the working device.In the process of operation, the front frame will bear the load from the working device, and will be subjected to severe impact load when driving or working on the bumpy road surface, which is prone to damage and failure.So it is very important to simulate the kinematics and dynamics of the working device and the front frame at the beginning of the design, and to analyze the strength of the front frame.In this paper, the 3D model of loader working device and front frame is established by using 3D software Pro/E, and the virtual prototyping technology and finite element analysis method of modern design method are used to study it.Firstly, the loading condition of the loader during operation is analyzed, and then the virtual prototype model is established in the multi-body dynamics software ADAMS, and the kinematics and dynamics simulation is carried out.The kinematics simulation mainly analyzes whether the components of the working device will interfere in the working process, and obtains the maximum unloading height and motion track, etc. The dynamic simulation is divided into two different situations: symmetrical load and biased load.The stress change curves of each hinge point of front frame and working device are obtained by composite operation, and the basic data are provided for the finite element analysis of front frame.Then the geometric model of the front frame is introduced into the finite element analysis software ANSYS, and the finite element analysis model is established. According to several typical working conditions of the loader, the force corresponding to the hinge points of the front frame is read from the dynamic simulation results.The static strength of the front frame is analyzed and the stress cloud diagram and displacement cloud diagram of the front frame under different working conditions are obtained.According to the results of static strength analysis, the danger points in the front frame structure are determined, and the local structure is optimized and improved, and the rationality of the optimization results is analyzed.It can be seen from the obtained displacement cloud diagram and stress cloud diagram that the maximum displacement and stress of the front frame structure are obviously reduced: under the positive load, the maximum lifting force, the excavating condition,The maximum stress value was reduced from 420Mpa before optimization to 273Mpa.The maximum displacement was reduced from 1.568mm to 1.158mm, and the maximum stress value was reduced from 530Mpa before optimization to 264 Mpa. the maximum displacement was reduced from 2.684mm to 1.979mm.The maximum stress value is reduced from 503Mpa to 307 MPA and the maximum displacement is reduced from 1.956mm to 1.452 mm. under the condition of maximum lifting force shovel.The results show that the stress and strain distribution of the front frame is more reasonable after structural optimization.The modal analysis of the front frame is carried out, and the natural frequency and the natural mode are obtained. The vibration frequency of the external vibration source of the wheel loader is analyzed and calculated, which provides the basis for the further optimization design of the front frame and the design of the vibration absorber.Through the virtual simulation of the working device of the wheel loader and the finite element analysis of the front frame, the theoretical support is provided for the working device of the wheel loader and the structure design of the front frame.
【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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