Papers by Keyword: Bumper

Abstract: The automobile industry intends to consume more aluminium alloys in an effort to reduce the greenhouse emissions through the cut in the weight of the passenger cars. Experimental X7475 aluminium alloy is a good candidate to achieve this mission. Past efforts targeted at exploring the aluminium for bumper beam applications and even the recovery of aluminium from recycled beverage can (RBC) were not with the aim of upgrading the 3xxx to a novel 7xxx alloy. The wt. % of Zn was 5.0, 4.5 and 4.0, while Mg was left at 1.50, 1.25 and 1.00 wt. % with Mn at a peak of 0.075, 0.050 average and a least wt. % of 0.025. Alloys were homogenized and taken through annealing (O), natural aging (T4) and artificial aging (T6). The effect of hardening phases such as MgZn2 (ICDD 034-0457) due to heat treatments on the physical and mechanical properties of the new X7475 alloys was investigated. Formation of precipitates affected the density and hardness of the alloys produced via stir casting route. A least hardness of 63.40 Hv was observed in alloy H with a density of 2.7264 g/cm3 while the maximum of 113.06 Hv was recorded against alloy C in as-cast (AC). The result has contributed to the database of experimental alloys with the possibilities of producing a new material from RBCs for bumper beam applications. Future investigation should employ design of experiment (DOE) in optimization of the heat treatment for better mechanical properties.

Abstract: This paper presents the analysis methods for design of automotive bumper covers. The bumper covers are plastic structures attached to the front and rear ends of an automobile and are expected to absorb energy in a minor collision. One requirement in design of the bumper covers is to minimize the bumper deflection within a limited range under specific loadings at specific locations based on the design guideline. To investigate the stiffness performance under various loading conditions, a numerical model based on the explicit dynamic finite element analysis (FEA) using the commercial FEA solver, LS-DYNA, is developed to analyze the design. The experimental tests are also carried out to verify the numerical model. The thickness of the bumper cover is a design variable which usually varies from 3 to 4 mm depending on locations. To improve the stiffness of the bumper, an optimal design for the bumper under a pre-defined loading condition is identified by using the topology optimization approach, which is an optimal design method to obtain the optimal layout of an initial design domain under specific boundary conditions. The outcome of this study provides an efficient and cost-effective method to predict and improve the design of automotive bumper covers.

Abstract: Safety is one of important factors which has to be considered in designing automobile in the automotive industry. One of the components related to the automobile safety is bumper. Bumpers are attached on front and rear of vehicle’s body in order to protect the body from damage due to low speed crash. In this research, hollow glass microsphere (HGM) reinforced epoxy is used as the material for the bumper since this material has not been applied to this application yet. This research is conducted in order to find the ability of this composite material in absorbing impact energy from low speed crash by using finite element method. Thickness of the bumper varied from 4 mm to 8 mm with 1 mm increment. Low speed collision is simulated by following Economic Commission for Europe Regulation 42. The bumper energy absorption is analyzed and indicated by the internal energy, deformation, and equivalent stress from each bumper’s thickness.

Abstract: High-speed crashworthiness characteristics of aluminum alloy bumper were investigated both experimentally and numerically, and then lightweight deign was performed based on these studies. After the simulation results were analyzed, chose plate thickness matching as an optimization direction and got crashworthiness indicators: cross-sectional force, energy absorption, and specific energy absorption (SEA). Design of experiment (DOE) for initial 25 sampling points, which provide input data for approximation, is implemented using the optimal Latin hypercube design (OLHD) method. Polynomial response surface (PRS) models, which are used to approximate LS-DYNA simulation models, are built using the moving least square (MVS), whose all coefficients of determination are over 0.97, indicated high accuracy. The simulation results of optimal designs, which are obtained after 52 iterations of genetic algorithms (GA), show that the mass loss of 30.8%, while energy absorption increase of 4% , SEA increase of 50.3%, and crushing forces decline.

Abstract: Double layer inflating safe cushion made of rubber and plastic or foam is developed to replace original foam inside bumper, the performance test of the designed safe cushion indicates the cushions advantage of lightweight and shrinkability, while the CAE simulated analysis proves that the cushion can protect pedestrians better and reduce the weight, showing a vast development potential.

Abstract: The present study aimed at developing an aluminium car bumper unit to replace the steel ones by using optimization based on experimental and FEM simulation results. The topology optimization method and response surface methodology (RSM) were applied in order to achieve an optimized design for the cross section of the crossbeam and the crash box, respectively. The three-points bending test and crash test for bumper unit were simulated to evaluate the optimization processes. The 6061 and 6063 aluminium alloy bumper unit has a weight reduction of 67% compared to the steel ones. The new extrusion dies were manufactured to produce profiles for the crossbeam and the crash box, respectively. Then the optimized extrusion profiles of crossbeam and crash box were verified by experimental studies. The performance tests were arranged to validate the experimental product. The mechanical properties of extruded aluminium crossbeam and crash box can satisfy the design requirements of products. The results indicate that the new designed unit can change the whole design of automotive parts for crash energy absorption, and definitely contribute to drastic weight reduction of steel parts.

Abstract: The computer simulation method is used to study the crashworthiness of car bumper system. Firstly, the CAD model of the car and bumper system is established in CATIA. The pre-processing for the model is finished in Hyper-Mesh and the finite element model is established. Then the process of crash simulation is calculated in Pam-Crash. The simulation results are compared with the test results to verify the accuracy of the finite element model. Finally, the low-speed crash simulation of the bumper system is conducted. The crash displacement and deformation of the bumper system are forecast through the process of simulation, which can provide a reference for the next design and improvement.

Abstract: All over the world at present, injuries and fatalities from road accidents are a significant problem, especially occurred to pedestrians from passenger cars. Most of the fatal accidents between car and pedestrians prove deadly because of the head to hood impact. This paper aims to develop a bumper to avoid from passenger car’s fatal head impact for pedestrian protection, and most importantly, the impact of different objects with passenger car bumper needs to be recognized. Firstly, a pendulum system is constructed to perform the fundamental research which is concentrated on the response pattern of impact-object simulation tests, and we confirmed the application possibility for the method of discriminable pattern recognition whether impact-object is human-like or not by means of neural networks using smart PZT materials. Finally, the impact characteristics analyses can provide enough pattern recognition indices which can be developed and then used to recognize the impact information by two different neural networks.