Applied Mechanics and Materials Vols. 490-491

Abstract: Elliptical vibration cutting (EVC) process and three dimensional cutting surfaces are analyzed in this paper to understand the formation of surface topography. The model of EVC surface topography is established based on curved surface remove function under the assumption that the tool edge is sharp enough. And simulation analysis of surface topography is conducted with different feed offset ratios. Results indicate that RMS change with feed offset ratios λ. The range of RMS is larger when feed offset ratio ranges from both 0 to 0.4 and 0.6 to 1, while the range is smaller when feed offset ratio changes from 0.4 to 0.6. Whats more, RMS reaches the minimum when feed offset ratio is 0.5. The present research provides some references for reducing the height of vibration ripples and improving EVC surface quality.

Abstract: More and more high strength steel panels are used in the Auto assembly for the reason of reducing pollution emissions and fuel consumption. The springback predication with different drawing styles for A pillar reinforcement plate is studied in this paper. The drawing process is optimized with different height drawbead for getting a reasonable forming result without obvious crack areas. An open drawing is used to study the possibility of reducing the blank size, but the measuring results show that the springback value predicted with close ends drawing is very close to the real tryout results and more lower than open ends drawing. So the open end drawing method can not be used in the tryout from the perspective of reducing the springback value.

Abstract: A major role of automotive engineers is to improve fuel efficiency and vehicle safety. However, it is very difficult to improve both of these requirements at the same time. So they deal with the design of structural reinforcements in hopes to improve the crush strength, but minimize the weight of the automobile body. Forming simulation has been playing increasingly important role in this field to save time and cost and the accuracy of the simulation argued against the real life results. In this paper The Auto Center pillar reinforce plate is studied by finite element method, and forming process is optimized according to full flow simulation. The simulation shows that the FEM can make the tryout process better to get high success rate and shorter time.

Abstract: This paper makes a static strength calculation and fatigue life prediction of a car's rear axle. To find out the dangerous stress and strain points of the bridge shell by making calculation analysis of the structure strength and stiffness of the rear axle bridge shell by using finite element analysis software, MSC.Patran and MSC.Nastran. Using MSC.Fatigue software on the rear axle to make an analysis of its fatigue life base on the finite element analysis, and make a modal analysis with MSC.Nastran software.

Abstract: Type 6-6 Stewart Parallel Mechanisms have been used widely in industries nowadays. Because of the influence of inevitable flexible deformations of each structural part, the loss of mechanism motion accuracies are obvious. It reported an effective rigidity and flexibility coupled reliability calculation method for this kind of mechanism. Firstly, it built a parameterized 3-D virtual model of this mechanism in ADAMS, and then used user defined function (a function in VC++ software) to simulate the stochastic error distributions; through this method, a Monte Carlo parametric model was built, and this was a basis for subsequent reliability calculation. Secondly, it programmed a reliability calculation system for this mechanism and performed multiple dynamic simulations to obtain the mechanism reliability data. This method took the influence of key parts flexible deformation on mechanism motion accuracy into account, and included simplicity (no need to solve complex mathematic model) and high accuracy which make it highly promising for application in mechanism design.

Abstract: In order to obtain frequencies and modal shapes of a nuclear containment vessel, the computational analyses have been carried out through free structure finite element analysis software. The finite element model of the vessel is built with shell element and solved by the type of the dynamics frequency solver. Results show that mainly deformation area is on the vessels cylindrical shell and the maximum displacements occur at its center. Compared with the design validation values, the frequencies obtained are a little lower. It may be because that the model built here is a completely vessel shell without any hatches or attachments. It is provided that a reliable method of computational structural analyses for the nuclear containment without commercial software cost.

Abstract: Parameterized model of combine harvester frame is created using the DM module of ANSYS Workbench in this paper. Analysis on the strength and stiffness of the frame is implemented to estimate its safety and economy. According to the analysis result, optimization is made to save material appropriately. Modal analysis of the frame is proceeded to study its natural frequency and compare it with external excitation frequency.

Abstract: Determination of sliding body saturated permeability coefficient has an important significance for groundwater dynamic field, deformation and stability of reservoir landslide. Based on in-depth analysis of landslide geological characteristics, groundwater monitoring data, rainfall and reservoir water lever in Three Gorges Reservoir, it is found that reservoir water level is the main factor which affecting the groundwater dynamic field. According to two layers of sliding body, the saturated permeability coefficient test plan of two factors and three levels has been designed. Based on saturated-unsaturated seepage finite element and the reservoir water level fluctuation curve, groundwater saturation line has obtained under different combinations of parameters. Combined with genetic algorithm, an optimal neural network model was established to describe the nonlinear relationship between the sliding body saturated permeability coefficient and borehole water level. Then based on the monitoring data of borehole water level, the saturated permeability coefficient of two layers sliding body can be gotten. Finally, with the inversion parameters, it is found that the calculating water level results and the actual level of underground water are in good agreement. Results show that the inverse thought and method is feasible and effective, which can provide reference for the similar engineering.

Abstract: The mechanical system and controlling system of test bench of safety belt emergency locking property are designed. Safety belt emergency locking property of a moving cars rider can be simulated by changing direct currents acceleration, so multifarious cars safety belt emergency locking property can be examined by the equipment which is developed by using engineering computer as control center,PARKER1505 and VC6.0.Fuzzy PID control algorithm is adopted to decrease the influence and enhance the systems robust.

Abstract: in this paper, we mainly introduce the principle of the flexible blank drawer forming (FBDF), and establish the limited element model of the FBDF process. Then we make a numerical analysis on the hemispherical parts, and study the effect made on the result of shaping by damping force, friction coefficient as well as material parameter in per unit area. Through the analysis of the numerical simulation result, we can conclude that the greater the yield limit and elasticity modulus, the larger blank drawer force is required to form the shape; the more smooth the material surface, the less resistance to deformation will have. All this contributes to good quality of forming parts.