Fluid-Structure Interaction Finite Element Analysis Of Light Vehicle Hydraulic Cab Mount

With the remarkable improvement of people's living standard, the consumers in modern society have higher requirement to the comfort of automobile. The main vehicle vibration is caused by the rough road and engine work. In order to isolate these vibrations and improve ride comfort, various mounts are widely used. The two familiar mounts are engine mount and cab mount. The former isolates vibration between engine and frame, and the latter is used to isolate vibration between cab and frame. Therefore, the development of mount which has good performance of vibration isolation is the important link in modern automobile design and production.According to the performance of vibration isolation from low to high level, there are four types of mounts, rubber mount, hydraulic mount, semi-active mount and active mount. Rubber mount has simple structure and lower cost, but poorer performance. Semi-active and active mount have superior isolation performance, but high cost. Their performance is often not stable enough because of the complicated structure. Hence hydraulic mounts are widely used in cars and light vehicles.Hydraulic mount consists of rubber and liquid. The nonlinear characteristics of these materials significantly increase the difficulty of isolation mechanism study. At present, most experts at home and abroad use a method called lumped-parameter, which is based on experiment. This method applies to product optimization, but has several limitations in product design. As computer technology is developing rapidly, the finite element method solves the above difficult points. The thesis is based on a key program of the science and technology department in Jilin province, automobile rubber isolation system and the key technology in Industrialization of relevant components. The thesis focuses on characteristics of a light vehicle hydraulic cab mount using FSI (fluid-structure interaction) finite element method. The main contents are as follows.Firstly, the size and position of each part in hydraulic mount must be measured accurately. Based on measurement data, the 2D and 3D geometric model are established. We can form complex finite elements mesh on it in pre-processing finite element software. Then the mesh models are imported into FSI software, with associated manipulations, such as material definition, boundary conditions adding, constraints and loads applying, etc. A FSI finite element model of hydraulic mount is built. Performing simulations of the model, we can obtain the isolation characteristics of hydraulic cab mount.According to the engineering 2D drawings above, we process all the parts and assemble them with proper and effective machining technics. The qualified hydraulic cab mounts are produced. And then, in order to validate and perfect the finite element model, the isolation characteristic tests of hydraulic mounts must be taken.Finally, we conduct the parametric studies on hydraulic mount, and find the relationship between model parameters and the isolation characteristics. On the basis of these laws, we can reveal the fluid-structure interaction in hydraulic mount, and master its isolation mechanism.As we know, different vibration isolation systems in automobile have different demands for the isolation characteristics of hydraulic mount. The study results in this thesis can provide theoretical foundations, research methods and production guidances in the design and optimization process of hydraulic mount.