Abstract

Composite materials are being widely used in automobile industry in order to meet the ever increasing demand to achieve significant weight reduction by maintaining the performance levels. Additionally, there are a number of challenging crashworthiness criteria set by the regulating authorities in various countries for vehicle safety, which the vehicle has to qualify. In these cases composites can be very useful as they exhibit high strength to weight ratios. But, deformation modes of composites are more complex when compared to metals, due to which it is more important to analyse the behaviour of composites under impact. In this study four types of cross sections (square, cylindrical, hexagonal and decagonal) were considered for the geometric shapes of GFRP (glass fiber reinforced plastic) crash boxes. Drop weight impact testing is widely used for studying the behaviour of parts subjected to impact loadings. The drop weight impact testing is highly dynamic in nature and in addition various factors like data acquisition signal noise (disturbance) requires the user to test 3–4 samples for each test specimen, for repeatability and minimisation of errors, which thereby increases the total number of testing samples. Therefore, in practise only a limited number of specimens can be actually tested using drop weight impact test considering the number of specimen samples to be manufactured and the cost involved in it. In this paper the development of numerical simulation model for drop weight impact test and its correlation with the real time drop weight impact testing was discussed in detail. *PART_COMPOSITE model along with *MAT58 material card was used for laminated GFRP composite specimen in Ls-Dyna along with calibration of parameters like longitudinal compression stress limiting factor (SLIMC1) and softness factor (SOFT) for simulation. The numerical simulation was correlated with the experimental data using correlation factors. The deformation modes as well as the F-D (force versus displacement) curves and SEA (specific energy absorption) values were found to have a close match between experiments and finite element simulations.

摘要

复合材料在汽车工业中被广泛使用，以满足不断增长的通过保持性能水平来实现显着减重的需求。此外，各国监管机构为车辆安全设定了许多具有挑战性的耐撞性标准，车辆必须符合这些标准。在这些情况下，复合材料非常有用，因为它们具有高强度重量比。但是，与金属相比，复合材料的变形模式更为复杂，因此分析复合材料在冲击下的行为更为重要。在这项研究中，GFRP（玻璃纤维增​​强塑料）碰撞盒的几何形状考虑了四种类型的横截面（方形、圆柱形、六边形和十边形）。落锤冲击试验广泛用于研究承受冲击载荷的部件的行为。落锤冲击测试本质上是高度动态的，此外，数据采集信号噪声（干扰）等各种因素要求用户为每个测试样本测试 3-4 个样本，以实现可重复性和误差最小化，从而增加总数的测试样品。因此，考虑到要制造的样品数量和所涉及的成本，实际上只有有限数量的样品可以使用落锤冲击试验进行实际测试。本文详细讨论了落锤冲击试验数值模拟模型的开发及其与实时落锤冲击试验的相关性。*PART_COMPOSITE 模型和 *MAT58 材料卡​​用于 Ls-Dyna 中的层压 GFRP 复合材料试样，并校准纵向压缩应力限制因子 (SLIMC1) 和软度因子 (SOFT) 等参数进行模拟。数值模拟与使用相关因子的实验数据相关。变形模式以及 FD（力与位移）曲线和 SEA（比能量吸收）值在实验和有限元模拟之间具有密切匹配。