翻转式薄壁结构吸能特性研究及其在吸能盒中的运用

发布时间：2018-03-18 03:25

本文选题：耐撞性　切入点：能量吸收　出处：《华南理工大学》2015年硕士论文　论文类型：学位论文

【摘要】：随着交通事故率的不断递增,吸能构件的耐撞性能在保障乘员生命与财产安全过程中发挥着越来越重要的作用。翻转管作为新式吸能结构在碰撞时具有高度的载荷稳定性以及能量吸收性能,但目前国内的相关研究应用却十分缺乏。基于对碰撞安全性的需要,本论文对翻转管的变形模式与吸能特性进行研究,对翻转式吸能元件进行结构设计,并最终将其应用于汽车吸能盒中。具体研究内容如下:(1)论述了自由翻转的变形模式与吸能机理。将翻转管与圆管、六边形管和多胞管的吸能特性进行对比,发现翻转管的主要吸能优势在于高度的载荷一致性,但有效压缩距离较短。另外对翻转变形模式的研究发现,圆环区宽度和加载速度均会对变形趋向性产生影响,管件材料会对变形稳定性产生影响。(2)提出二节翻转管变形可控的设计方案,通过引入倒角和采用变厚度使有效压缩行程最大化。提出二节与三节锥形翻转管的尺寸设计方程,该方程能够使锥形翻转管的有效压缩行程最大化,并通过数值模拟得到验证。另外通过倒角与变厚度进行三节直翻转管的结构设计。根据现有的翻管成型工艺给出了两种结构加工成型方案,为翻转管的实际工程应用提供技术支撑。(3)将翻转变形吸能模式应用到车用吸能盒的设计当中,利用前纵梁内部空间提高吸能盒的压缩行程。并通过在吸能盒中填充泡沫铝材料提高其斜向载荷下的变形稳定性,同时吸能量也得到提高。(4)对填充式吸能盒进行轴向抗冲击模拟试验。对于同一壁厚的翻转管来说,泡沫铝孔隙率增大,吸能量与压溃峰值力均线性递减。比吸能也随孔隙率增大而下降,但存在壁厚越小下降幅度越大的特点。同时还发现孔隙率为82.4%左右的泡沫铝填充结构其压缩力效率最高。(5)以一定压缩距离下的吸能量最大化、结构总质量最小化为优化目标,对填充式翻转吸能盒进行结构参数进行多目标优化。采用响应面近似模型,并通过第二代非支配排序遗传算法求得Pareto最优解,为结构设计提供参考。
[Abstract]:With the increasing traffic accident rate, The crashworthiness of energy absorption components plays a more and more important role in the process of ensuring the safety of occupants' lives and property. As a new energy absorption structure, the flip tube has high load stability and energy absorption performance. Due to the need of collision safety, this paper studies the deformation mode and energy absorption characteristics of the flip tube, and designs the structure of the flip energy absorption element. Finally, it is applied to the energy absorption box of the automobile. The specific research contents are as follows: 1) the deformation mode and energy absorption mechanism of the free turnover are discussed. The energy absorption characteristics of the flip tube and the circular tube, the hexagonal tube and the polycell tube are compared. It is found that the main energy absorption advantage of the flip tube lies in the consistency of the height of the load, but the effective compression distance is relatively short. In addition, it is found that the width of the ring and the loading speed will affect the deformation tendency. Tube fitting material will have an effect on deformation stability. (2) A design scheme of controllable deformation of two-section flip tube is proposed. The effective compression stroke is maximized by introducing chamfer and variable thickness, and the size design equation of two-section and three-section taper tube is proposed. The equation can maximize the effective compression stroke of the taper tube. In addition, through chamfering and variable thickness, the structure design of three straight inverted tubes is carried out. Two kinds of structural processing schemes are given according to the existing turning process. To provide technical support for the practical engineering application of the flip tube. (3) to apply the flip deformation energy absorption mode to the design of the vehicle energy absorption box. The compression stroke of the energy absorption box is increased by using the inner space of the front longitudinal beam, and the deformation stability of the energy absorption box under oblique load is improved by filling the foam aluminum material in the energy absorption box. At the same time, the absorption energy is also increased. 4) the axial impact simulation test is carried out on the filled energy absorption box. For the same wall thickness flip tube, the porosity of aluminum foam increases. The energy absorption and peak crushing force decrease linearly, and the specific energy absorption decreases with the increase of porosity. However, the smaller the wall thickness is, the greater the decrease of wall thickness is. It is also found that the maximum compression force efficiency of aluminum foam filled structure with porosity of about 82.4% is maximized at a certain compression distance, and the optimization goal is to minimize the total mass of the structure. In this paper, the structure parameters of the filled flip energy absorption box are optimized by multi-objective method. The response surface approximation model is adopted and the Pareto optimal solution is obtained by the second generation undominated sorting genetic algorithm, which provides a reference for the structure design.
【学位授予单位】：华南理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U491.6

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