【作者】 姚晓璐；

【导师】 马力；

【作者基本信息】 武汉理工大学 ， 车辆工程， 2008， 硕士

【摘要】 本文首先对自卸半挂车举升稳定性的课题背景进行了介绍,结合自卸半挂车的发展趋势和项目委托企业的实际要求,阐述了研究本课题必要性和迫切性,以及研究的主要的目的和意义。在详细分析了自卸半挂车稳定性的国内外研究现状的基础上,综合考虑企业的具体要求,提出了本文研究的主要内容。结合国内外研究现状和本文的研究内容,选择多体动力学理论和拓扑优化理论作为课题研究的理论工具,利用多体动力学理论来研究各种因素对自卸半挂车举升稳定性的影响,拓扑优化理论来进行部件的优化设计,对这两个理论进行了具体分析。自卸半挂车的稳定性包括举升机构的部件稳定性和整车的稳定性。举升机构部件的稳定性显然会对整车的稳定性造成影响,但是整车的稳定性影响因素比较多,因此,先对举升机构部件的稳定性进行了研究,全面分析了举升机构部件的稳定性,确定三角臂是举升机构稳定性中的薄弱环节。在对三角臂一般情况下受力分析的基础上,建立了基于柔性连接的举升机构参数化多体动力学模型,研究了货厢质量偏心、三角臂安装误差和货厢与车架铰接点安装误差等因素对三角臂受力状况的影响。考虑到三角臂极易受到附加力矩的影响和其结构的稳定性比较差,对三角臂进行了结构优化设计。采用变密度法,挑选举升过程中六个受力比较典型的工况,在有限元软件hypermesh中对三角臂做了拓扑优化。优化后显著提高了三角臂的抗弯和抗扭性能,并有效地减轻了其重量。然后对自卸半挂车整车的建模进行了研究。自卸半挂车整车是个复杂的多体系统,在综合考虑研究内容、模型规模和模型精度的情况下,对自卸半挂车进行了必要简化,建立了多体动力学模型。通过自由度和仿真验证,确定所建立的模型是可信的,可以用来进行自卸半挂车整车举升稳定性的仿真研究。最后,在对影响自卸半挂车举升稳定性的因素进行综合分析的基础上,本文选择研究车架柔性和作业场地这两个因素,研究其对自卸半挂车举升稳定性的影响。通过改变车架的柔性,采用五个模型进行仿真对比,研究了车架柔性对自卸半挂车的静态稳定性和动态稳定性影响。在场地因素中选择侧向坡、地面不平和折叠这三个典型状况研究了场地因素对自卸半挂车举升稳定性的影响。更多还原

【Abstract】 The paper firstly introduced the background of the subject on lifting stability of dump tractor-semitrailer. At the same time, it also elaborated the necessity and urgency, as well as the main goal and significance of research on this subject, considering the developing tendency and the actual requests of enterprise. Based on analyzing the present research situation at home and abroad of the stability of dump tractor-semitrailer in detail, and synthetically considering the enterprise’s specific requests, it proposed the main content of this paper.Combined with the domestic and foreign present research situation and the research content of this paper, the multi-body dynamics theory and the topological optimization theory were selected as theory tool. The multi-body dynamics theory is used to research the various factors’ influence on the lifting stability of dump tractor-semitrailer, and the topological optimization theory for optimized design on the parts. Then the paper analyzes these two theories concretely.The stability of dump tractor-semitrailer includes stability of the part of lifting mechanism and entire vehicle stability. Obviously the stability of the part of lifting mechanism influences the entire vehicle stability, but there are much more factors influence the entire vehicle stability at the same time. Therefore, it researched the stability of lifting mechanism early. With comprehensively analyzed each part of the lifting mechanism, it was concluded that the triangle arm is the weakest component of lifting mechanism. Based on the force analysis of the triangle arm in its ordinary circumstance, the paper established a parametric multi-body dynamic model of the flexible connected lifting mechanism, and also studied the factors which influence the stress condition of triangle arm, such as the mass eccentricity of the boxcar, the mounting error of the triangle arm and the mounting error of the joint point of the boxcar and frame.Considered the triangle arm is extremely and easily influenced by the additional torque and its self-bad structure stability, the paper carried on the structure optimization design to the triangle arm. By using the variable density means, the triangle arm was topology optimized under the six typical force conditions during the lifting process in finite element software HYPERMESH. It was shown that the anti-twists function and the anti-bends function have been remarkably improved, and its weight has been reduced effectively.Then, the paper researched the modeling method of entire dump tractor-semitrailer. Dump tractor-semitrailer is a complicated multi-body system. Combined with the content of this paper, model scale and model precision, it simplified the real dump tractor-semitrailer and got the multi-body dynamic model .After degree of freedom and simulation check ,it confirmed that the model is credible, which can be used to research the damping stability of dump tractor-semitrailer.Eventually, the paper studied the influence of the flexibility of frame and ground status on the damping stability of dump tractor-semitrailer. From changing the flexibility of frame in five models, the paper researched the influence of the flexibility of frame on the static stability and dynamic stability of dump tractor-semitrailer. The ramp, roughness and jackknifing were chose as the typical ground status to study the influence of ground status on the damping stability of dump tractor-semitrailer.更多还原