Study On Automobile Fuel Tank Structure Design And Forming Quality Control

Fuel tank is one of the important components of the fuel supply system in automobile. Traditionally, the design flow of a fuel tank follows the course of trial- producing – test – refining – re-trial – and re-test. Engineers design the product according to their experiences, and checkout the performance by the prototype test. Thus, a new type must go through several rounds of modification and longtime refining, this always lead to a high financial pressure and waste of time. With the high speed of the development of the national automobile industry, traditional design method can no longer satisfy the quickly responding requirement of the market.The main idea of this paper is to utilize the modern CAD/CAE technique to design a metal fuel tank for a newly developed car - CV9 at its design stage. After settle the geometric structure of the fuel tank, we simulated the vibration test according to the state standard and the company standard to make sure that it has enough intensity and fatigue life. Based on the discussion of the forming parameters we carried out the simulation of the forming process of the fuel tank to make sure its manufacture feasibility. Some control methods were also put forward to ensure the forming quality of the fuel tank.Firstly, according to the volume requirement and the full car configuration the author designed the geometry of CV9 fuel tank using 3D software UG. Secondly, the author built the finite element model for the fluid structure interaction vibration test using Fluid80, Solid95 and Shell63 elements. The intensity analysis and the fatigue life prediction were also carried out according to the state standard and the company standard. Further evaluation of the intensity and the fatigue life was brought forward based on the comparison with the 6350 fuel tank.Thirdly, the forming process simulation of CV9 fuel tank was carried out, the defects of the original design was revealed and refinements, such as optimizing the drawbead and binding force, were adopted to avoid splitting and wrinkling. During this research the reasonable artificial mould speed was discussed using a barrel forming simulation, considering the energy and the deformation type, the author come to the conclusion that the mould speed should not exceed 10m/s, or the excessive inertia effect will lead to an improper result. The friction coefficients between the blank and the moulds were also studied by the comparing analysis of 6350 fuel tank. Finally, the author also did some research work in how to use ALE (Arbitrary Lagrangian-Euler method) finite element method to solve fluid-structure interaction (FSI) problem. The model for FSI analysis of CV9 fuel tank was built, but only partial calculation was carried out with the limit of the poor hardware. So, the high performance computer is the foundation of the application of ALE method in 3D FSI problems.