液力减振器结构异响形成过程的流固耦合仿真与分析

发布时间：2019-03-17 11:59

【摘要】：随着提高汽车安全性、稳定性及操纵性的相关技术的快速发展，人们对汽车的乘用舒适性提出了更高的要求，，而严重降低乘用舒适性的汽车噪声，受到学术界及企业的关注。经过多年的努力，汽车上其他噪声源已经得到较好的控制，因此，筒式液力减振器的异响渐渐成为汽车噪声中最突出的问题之一，并成为重要的研究课题。结构异响作为筒式液力减振器异响问题中最突出、最复杂的一种异响，是减振器异响研究中的重点。虽然对其进行了大量的研究，但基于试验的研究方法缺乏对减振器内部流场特性的研究，且由于结构异响形成机理的复杂性，已有的研究在结构异响的振动频率分布方面并未形成一致的结论，表明减振器结构异响问题还需进行更深入的研究。本文以某筒式液力减振器为研究对象，针对引起结构异响的空程冲击过程及补偿阀开启过程，利用有限元分析技术分别进行了仿真与分析。具体对筒式液力减振器结构异响问题进行了以下深入研究： ①建立了模拟筒式液力减振器空程冲击过程的气液两相流固耦合模型，同时建立了无空程距离的正常筒式液力减振器模型，并进行仿真计算。文中对油液流经空程距离后对活塞杆的冲击引起的活塞杆轴向振动进行了分析，并与正常减振器的活塞杆轴向振动进行了对比分析，同时对流体模型中的气液两相流动进行了详细分析。 ②建立了补偿阀开启时的减振器流固耦合模型，进行了仿真计算。减振器补偿阀开启时，补偿阀弹簧的预紧力及补偿阀片的粘附作用导致补偿阀片的延迟开启，对由此造成的阻尼力波动以及活塞杆的轴向振动进行了详细分析，同时对流体模型中油液的流动特性进行了分析。 ③结合文中所建立的减振器流固耦合模型，分别对固体有限元数值理论、流体有限元数值理论及流固耦合数值理论进行了介绍，并对模型仿真过程中的难点问题及处理方法进行了重点分析。本文提出利用有限元方法对减振器异响问题进行深入研究，能更好地对减振器内部流场的观察和解决减振器异响问题，且有限元方法在减振器研究开发阶段更具优势，故研究具有一定的实际工程意义，研究结果具有一定的应用价值。
[Abstract]:With the rapid development of related technologies to improve vehicle safety, stability and maneuverability, people put forward higher requirements for vehicle ride comfort, and seriously reduce the vehicle noise of ride comfort, which has attracted the attention of academia and enterprises. After many years' efforts, other noise sources on the automobile have been well controlled. Therefore, the abnormal noise of the cylinder hydraulic shock absorber has gradually become one of the most prominent problems in the automobile noise and has become an important research topic. As one of the most prominent and complicated abnormal noises in cylindrical hydraulic shock absorbers, the structural abnormal noise is the focus of the research on the abnormal sound of shock absorbers. Although a great deal of research has been done on it, the experimental-based research method lacks the research on the internal flow field characteristics of the shock absorber, and because of the complexity of the mechanism of the formation of the abnormal sound of the structure, There is no consistent conclusion on the vibration frequency distribution of the structural abnormal sound, which indicates that the abnormal vibration problem of the vibration absorber needs to be further studied. In this paper, a cylinder type hydraulic shock absorber is taken as the research object, and the finite element analysis technique is used to simulate and analyze the process of air-distance impact and the opening process of compensation valve which cause the structural abnormal sound. The structure of cylindrical hydraulic shock absorber is studied as follows: (1) A gas-liquid two-phase fluid-solid coupling model is established to simulate the air-liquid shock process of cylinder-type hydraulic shock absorber. At the same time, the model of normal cylinder type hydraulic shock absorber without empty distance is established, and the simulation calculation is carried out. In this paper, the axial vibration of piston rod caused by the impact of piston rod is analyzed, and the axial vibration of piston rod is compared with that of normal shock absorber, after the oil flows through the empty distance, the axial vibration of piston rod caused by the impact of piston rod is analyzed and compared with that of normal shock absorber. At the same time, the gas-liquid two-phase flow in the fluid model is analyzed in detail. 2. The fluid-solid coupling model of the damper when the compensation valve is opened is established, and the simulation calculation is carried out. When the damper compensation valve is opened, the pre-tightening force of the compensation valve spring and the adhesion of the compensating valve plate lead to the delayed opening of the compensation valve plate, and the damping force fluctuation and axial vibration of the piston rod are analyzed in detail. At the same time, the flow characteristics of oil in the fluid model are analyzed. 3 the solid finite element numerical theory, fluid finite element numerical theory and fluid-solid coupling numerical theory are introduced in combination with the fluid-solid coupling model established in this paper. The difficult problems in the process of model simulation and the methods to deal with them are analyzed in detail. In this paper, the finite element method is proposed to study the abnormal sound of shock absorber in depth, which can better observe the internal flow field of damper and solve the problem of shock absorber abnormal sound, and the finite element method has more advantages in the research and development stage of shock absorber, and the finite element method has more advantages in the research and development of shock absorber. Therefore, the research has certain practical engineering significance, and the research results have certain application value.
【学位授予单位】：重庆大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TB535.1;U461.4

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