形状记忆合金汽车吸能装置特性研究

发布时间：2018-06-13 09:01

本文选题：形状记忆合金 + 汽车吸能装置　；参考：《吉林大学》2017年硕士论文

【摘要】：车辆安全性问题直接关系到人的生命和财产安全,一直以来受到广大汽车消费者和研发人员的高度重视。为提高汽车的安全性,一些传统的吸能材料和吸能结构被广泛应用于汽车被动安全领域。但是受到汽车轻量化原则的约束,这些吸能材料和结构的应用受到一定的限制。近年来,智能材料和智能结构的出现为解决汽车安全和轻量化之间的矛盾提供了新思路。形状记忆合金(SMA)作为热门的智能材料,具有低密度、高耗能、抗冲击和耐腐蚀等优良力学特性。将形状记忆合金作为缓冲吸能材料应用于汽车安全领域,可以有效地提高和丰富汽车碰撞吸能保护效果。本文对室温下分别为马氏体和奥氏体结构的两种Ni Ti SMA丝的静态吸能特性进行了详细的实验研究。在此基础上把Ni Ti SMA丝作为一级吸能材料,设计了一种SMA汽车二级吸能装置,并对该装置的各级吸能进行了实验和仿真研究。论文的主要工作内容和结果展示如下:(1)利用拉伸机和差示量热扫描仪测得了马氏体Ni Ti SMA丝和超弹性Ni Ti SMA丝的相变应力值和相变温度等参数,并简要介绍了三种SMA本构关系,为之后的准静态拉伸试验和仿真分析作准备。(2)对两种Ni Ti SMA丝进行了详细的准静态拉伸实验研究,分析了应变幅值、拉伸速率、温度以及循环加载对SMA力学性能的影响,尤其是对吸能密度的影响。通过ANSYS软件对两种SMA丝进行了不同幅值的准静态拉伸仿真,仿真结果与实验结果对比分析表明,整体误差控制在10%以内,验证了仿真分析的准确性。(3)根据SMA丝在断裂情况下的应力-应变曲线,结合铝合金断裂能公式对SMA丝拉断所需要的总能量进行了公式推导,并求得了各能量组分的吸能密度。研究结果显示,在拉断情况下,马氏体Ni Ti SMA丝的耗能密度远远高于超弹性Ni Ti SMA丝。(4)根据SMA丝的变形吸能特点,提出了一种新型的SMA汽车二级吸能装置,并分别通过实验和仿真对其冲击吸能特性进行研究。本文设计并搭建了一种丝式材料冲击实验测试装置,对两种Ni Ti SMA丝进行了不同质量载荷的冲击实验研究。实验结果显示,两种SMA丝均具有良好的冲击保护性能,并且随着冲击质量的增加,SMA丝的吸能密度也逐渐增大。对二级吸能套筒进行的仿真分析结果表明,由内外套筒组成的多腔结构在总吸能量和比吸能方面远远优于传统吸能盒。(5)利用SMA丝冲击测试装置,对马氏体Ni Ti SMA丝进行了不同温度下的冲击实验研究。实验结果表明,在特定温度区间内温度可以有效的改变SMA丝的力学性能。随着温度的不断升高,马氏体SMA丝的吸能密度显著增大。这充分验证了SMA吸能装置可以通过一定的控制策略实现冲击吸能保护的智能控制。
[Abstract]:Vehicle safety is directly related to the safety of human life and property, and has been highly valued by automobile consumers and R & D personnel. In order to improve the safety of automobile, some traditional energy-absorbing materials and energy-absorbing structures are widely used in the field of automotive passive safety. However, the application of these energy-absorbing materials and structures is limited by the principle of automobile lightweight. In recent years, the emergence of intelligent materials and intelligent structures provides a new way to solve the conflict between automotive safety and lightweight. Shape memory alloy (SMA) is a popular smart material with low density, high energy consumption, impact resistance and corrosion resistance. The application of shape memory alloy (SMA) as an energy absorber material in automobile safety field can effectively improve and enrich the protection effect of vehicle collision energy absorption. In this paper, the static energy absorption characteristics of two kinds of Ni Ti SMA wires with martensite and austenite structures at room temperature are investigated in detail. On the basis of this, the Ni-Ti SMA wire is used as the first class energy absorbing material, and a kind of secondary energy absorption device of SMA vehicle is designed, and the experiment and simulation of the energy absorption at all levels of the device are carried out. The main work and results of this paper are as follows: (1) the parameters of phase transformation stress and transformation temperature of martensite Ni Ti SMA wire and superelastic Ni Ti SMA wire are measured by means of drawing machine and differential calorimeter, and three kinds of SMA constitutive relations are introduced briefly. Two kinds of Niti SMA wires were studied in detail by quasi-static tensile test and simulation analysis. The effects of strain amplitude, tensile rate, temperature and cyclic loading on the mechanical properties of SMA were analyzed. Especially the influence on the energy absorption density. The quasi-static tension simulation of two SMA wires with different amplitudes is carried out by ANSYS software. The comparison between the simulation results and the experimental results shows that the overall error is controlled within 10%. According to the stress-strain curve of SMA wire under the condition of fracture and the formula of fracture energy of aluminum alloy, the formula of total energy needed for SMA wire breaking is deduced, and the energy absorption density of each energy component is obtained. The results show that the energy dissipation density of martensite Ni Ti SMA wire is much higher than that of superelastic Ni Ti SMA wire. The impact energy absorption characteristics are studied by experiment and simulation. In this paper, a device for testing the impact of wire materials is designed and built, and two kinds of Ni Ti SMA wires are tested under different mass loads. The experimental results show that both kinds of SMA wires have good impact protection performance, and the energy absorption density of SMA wire increases with the increase of impact mass. The simulation results of the two-stage energy absorption sleeve show that the multi-cavity structure composed of inner and outer sleeve is far superior to the traditional energy absorption box in total energy absorption and specific energy absorption, using SMA wire impact testing device. The impact test of martensite Ni Ti SMA wire at different temperatures was carried out. The experimental results show that the mechanical properties of SMA wires can be changed effectively by temperature in a specific temperature range. With the increasing of temperature, the energy absorption density of martensite SMA wire increases significantly. This fully verifies that the SMA energy absorption device can realize the intelligent control of shock energy absorption protection by certain control strategy.
【学位授予单位】：吉林大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U463.8;TG139.6

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