某农用自卸车举升机构底座断裂原因分析及结构优化

发布时间：2018-05-13 14:43

本文选题：农用自卸车 + 举升机构　；参考：《广西科技大学》2013年硕士论文

【摘要】：本文主要是针对某种农用自卸车在客户使用过程中发生了举升机构底座断裂的问题进行了研究，，研究的对象是广西某农用自卸车公司的连杆式举升机构，底座及副车架，运用ADAMS软件建立简化的举升机构模型然后仿真举升机构的卸载过程，可以得出各部件受力值随时间变化的曲线（特别是超载的情况）；使用ANSYSWorkbench对关键零件进行应力分析及副车架模态分析，然后对举升机构底座电测试验和副车架自由模态试验，验证软件仿真和分析的正确性。本文运用虚拟样机技术和有限元技术在农用自卸车设计方面进行了一些尝试及探索，具有一定的学术价值。主要做了以下工作：（1）根据自卸车举升机构的特点，结合虚拟样机技术，使用ADAMS软件建立自卸车举升机构的简化模型包括车厢、拉杆、油缸、油缸活塞杆等，查看整个机构的布置状况，检验干涉情况然后进行运动学仿真，不仅可以直观得到初始设计时各构件的受力情况，也能计算整个机构的初始举升性能. （2）使用有限元分析软件ANSYS Workbench对关键零部件（举升机构底座）及副车架进行参数化建模,网格划分,在有限元模型中添加ADAMS仿真得到的最大举升力及此时的角度，进行有限元分析得到底座应力云图。使用有限元软件对副车架及底座进行自由模态分析，求出副车架自由模态下前六阶非零固有频率及振形图，由计算的频率值可知副车架及底座的频率避开了发动机的频率，说明正常工作时是安全的。（3）根据ANSYS Workbench的模态分析和ADAMS的仿真分析结果，对副车架布置测试点的位置，然后进行模态试验测试，得到副车架试验的模态频率及振形图，对比试验数据和软件分析结果，验证了软件分析结果的可信度及模型的准确度。布置自卸车举升机构的测试点，对举升机构卸载时进行动态试验，验证了举升机构底座受力与软件分析结果基本是一致的，为下一步对举升机构底座断裂的分析奠定基础。（4）使用ADAMS软件建立举升机构的参数化模型，对举升机构各铰链点位置坐标进行参数化处理，选取合适的设计变量及目标函数进行优化，优化后举升机构卸载1.5x104kg载荷时油缸的最大举升为1.89E5(N)，油缸的初始举升力1.55E5（N）,P0等于0.82Pmax,小于0.85Pmax符合机构的性能要求，最大的举升力减少了32.5%，在ANSYS Workbench软件中建立优化后的模型，进行应力分析验证优化结构是符合要求。
[Abstract]:This paper mainly focuses on the research of the breakage of lifting mechanism base in the process of using a certain agricultural dump truck. The research object is the connecting rod lifting mechanism, the base and the sub-frame of a certain agricultural dump truck company in Guangxi. The simplified lifting mechanism model is established by using ADAMS software, and then the unloading process of the lifting mechanism is simulated. The curves of the stress value of each component with time (especially the overload) can be obtained. The stress analysis and the modal analysis of the subframe are carried out by using ANSYSWorkbench, and then the electric test and the free mode test of the base of the lifting mechanism and the free mode test of the sub-frame are carried out. Verify the correctness of software simulation and analysis. In this paper, virtual prototyping technology and finite element technique are used in the design of agricultural dump truck, which has certain academic value. The main tasks are as follows: According to the characteristics of the lifting mechanism of the dump truck, combined with the virtual prototyping technology, the simplified model of the lifting mechanism of the dump truck is established by using ADAMS software, including the carriage, the pull rod, the piston rod of the cylinder, and so on, and the layout of the whole mechanism is inspected. After the interference is checked and the kinematics simulation is carried out, the initial lifting performance of the whole mechanism can be calculated as well as the force situation of each member in the initial design. 2) using finite element analysis software ANSYS Workbench to parameterize the key parts (lift mechanism base) and sub-frame, to divide the mesh, to add the maximum lift force obtained by ADAMS simulation to the finite element model and the angle at this time. The stress cloud diagram of the base is obtained by finite element analysis. The free modal analysis of the subframe and the base is carried out by using the finite element software, and the first six non-zero natural frequencies and the vibration figure of the subframe are obtained under the free mode of the subframe. The frequency of the subframe and the base can be determined by the calculated frequency value, and the frequency of the subframe and the base avoids the frequency of the engine. Indicates that it is safe to work properly. According to the results of modal analysis of ANSYS Workbench and simulation analysis of ADAMS, the location of test points is arranged on the sub-frame, then modal test is carried out, and the modal frequency and vibration diagram of sub-frame test are obtained, and the results of test data and software analysis are compared. The reliability of the software analysis results and the accuracy of the model are verified. The test points of the lifting mechanism of the dump truck are arranged, and the dynamic test of the lifting mechanism is carried out when the lifting mechanism is unloaded, which verifies that the stress of the base of the lifting mechanism is basically the same as the result of the software analysis, which lays a foundation for the analysis of the fracture of the base of the lifting mechanism in the next step. The parameterized model of lifting mechanism is established by using ADAMS software. The coordinate of each hinge point of the lifting mechanism is parameterized, and the appropriate design variables and objective functions are selected to optimize. The maximum lift of the oil cylinder is 1.89E5N0 when the 1.5x104kg load is unloaded by the optimized lifting mechanism, and the initial lift force of the oil cylinder is equal to 0.82Pmax, which is less than that of the 0.85Pmax, and the maximum lifting force is reduced by 32.5%. The optimized model is established in the ANSYS Workbench software. Stress analysis is carried out to verify that the optimized structure meets the requirements.
【学位授予单位】：广西科技大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TH242

【参考文献】