异形薄壁结构的耐撞性研究及其优化设计

发布时间：2018-01-03 19:14

本文关键词：异形薄壁结构的耐撞性研究及其优化设计　出处：《湖南大学》2016年硕士论文　论文类型：学位论文

【摘要】：由于金属薄壁结构良好的吸能特性、显著的轻量化效应及较低的制造成本,其作为缓冲能量吸收装置被广泛地运用于汽车及飞机的前端结构,以达到保护乘客的目的。广大学者已经对圆形、方形、六边形等传统金属薄壁结构开展了大量的研究工作,为了进一步探究和提高金属薄壁结构的耐撞性,本文主要针对异形金属薄壁结构开展了一系列的研究,以直圆管为基础,对其径向和轴向进行函数变换,主要以下两方面的工作:(1)本文利用傅里叶函数展开圆管的横截面形状提出了一种新型的薄壁管状结构:傅里叶异形薄壁结构,并对其进行了准静态下的压缩实验,通过实验分析了其变形特点及吸能特性。进一步地,构建了傅里叶异形薄壁结构的有限元模型,主要包括材料及加载设置,网格划分及接触处理,将实验结果和有限元数值仿真结果进行对比,验证了所构建的有限元模型的有效性。然后,基于有效的有限元模型,分析了横截面形状、横截面周长及管壁厚度对该类结构变形模式及吸能特性的影响。结果表明:傅里叶异形薄壁结构的变形模式极大地受到横截面形状、横截面周长及管壁厚度的影响,同时傅里叶异形薄壁结构具有巨大的吸能潜力。最后,采用离散优化的方法对傅里叶异形薄壁结构进行了优化设计,获得其最优的设计参数。(2)本文利用正弦式三角函数控制圆管轴向形状的变化,提出了另一种新型的薄壁管状结构:正弦式波纹薄壁结构,并构建了正弦式波纹管的有限元模型,利用圆管的准静态压缩实验对其进行了模型验证。然后,基于有效的有限元模型,分析了波长与振幅对变形模式及吸能特性的影响,同时引入了载荷波动度的概念,分析了波长与振幅对结构载荷波动度的影响。进一步地,分析了名义直径和管壁厚度对变形模式的影响。结果表明:通过参数设计能够较好的控制和预测正弦式波纹管的变形模式,极大地降低初始峰值力。最后,利用拉丁超立方实验设计方法及径向基代理模型方法构建代理模型,采用非支配排序遗传算法对正弦式波纹管进行了多目标优化设计,获得了其Pareto最优设计解。
[Abstract]:Due to its good energy absorption characteristics, significant lightweight effect and low manufacturing cost, metal thin-walled structure is widely used as a buffer energy absorber device in the front end of automobile and aircraft. In order to protect passengers, many scholars have carried out a lot of research on traditional metal thin-walled structures, such as circular, square, hexagonal, in order to further explore and improve the crashworthiness of metal thin-walled structures. In this paper, a series of researches have been carried out on the special-shaped metal thin-walled structure, and the radial and axial function transformation has been carried out on the basis of the straight circular tube. In this paper, a new thin-walled tubular structure called Fourier special-shaped thin-walled structure is proposed by using Fourier function to expand the shape of the cross section of the pipe. The quasi-static compression experiments were carried out, and the deformation and energy absorption characteristics were analyzed. Furthermore, the finite element model of the Fourier special-shaped thin-walled structure was constructed, including material and loading settings. Mesh generation and contact processing, the experimental results and finite element numerical simulation results are compared to verify the validity of the proposed finite element model. Then, based on the effective finite element model, the cross-section shape is analyzed. The influence of circumference of cross section and thickness of tube wall on the deformation mode and energy absorption characteristics of this kind of structure shows that the deformation mode of Fourier special-shaped thin-walled structure is greatly affected by cross-section shape. The influence of cross section circumference and pipe wall thickness, and the Fourier profiled thin-walled structure has great energy absorption potential. Finally, the discrete optimization method is used to optimize the design of Fourier profiled thin-walled structure. In this paper, a new type of thin-walled tubular structure: sinusoidal corrugated thin-walled structure is proposed by using sinusoidal trigonometric function to control the change of axial shape of circular tube. The finite element model of sinusoidal corrugated tube is constructed and verified by quasi-static compression experiment of circular tube. Then, based on the effective finite element model. The influence of wavelength and amplitude on deformation mode and energy absorption characteristics is analyzed. The concept of load fluctuation is introduced, and the influence of wavelength and amplitude on structural load fluctuation is analyzed. The effect of nominal diameter and wall thickness on deformation mode is analyzed. The results show that the deformation mode of sinusoidal bellows can be controlled and predicted by parameter design, and the initial peak force can be greatly reduced. The Latin hypercube experimental design method and the radial basis function agent model are used to construct the agent model, and the non-dominated sorting genetic algorithm is used to optimize the multi-objective design of sinusoidal bellows. The Pareto optimal design solution is obtained.
【学位授予单位】：湖南大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：U463.8

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