摘 要

生活中，人们的乘用车在马力不变的情况下，正在越来越轻。而这是设计者们有意的去实现的，这样做的目的有很多，但最主要的目的还是在不影响操作性和安全性的前提下让乘客更舒适。本课题选择某型轿车的独立副车架，并且采用铝合金替换钢材的方式进设计以达到减轻重量的目的 。首先分析独立副车架，确立轻量化独立副车架的基本思路，接着测量数据建立三维模型，学习软件将三维模型转化为有限元分析模型，利用有限元分析软件如ANSYS等分析，并对换用铝合金材料后的独立副车架采用强度分析，判断是否可行。

进行研究前，我们要明确对副车架进行轻量化设计的目的和所要用的方法。具体而言，我们要阅读文献了解副车架的历史，研究它出现的原因和在汽车上的意义。并通过历史了解副车架的曾经起到的功能，最后学会设计副车架。副车架的结构特点，材料，型式，与车身连接方式等，我们也要有所研究。而这些都需要以阅读文献查找资料为基础。本课题采用铝合金替换的方式完成优化。因此在论文中也研究了铝合金，追述了铝合金在汽车生产制造的发展。

在这之后就要为有限元分析做准备了。首先选定一种载荷工况，对副车架进行强度的分析。计算出载荷和边界条件。为了进行有限元分析，我们需要学习辅助软件的使用，这里选用了ANSYS。有限元分析软件Ansys可以完成对独立副车架的三维模型进行简化处理，网格划分，施加刚性连接和载荷工况，建立独立副车架的有限元分析模型。

本课题的研究工作，参考了现代汽车的发展，同时也为现代汽车业的发展提供了参考

关键词: 独立副车架 汽车轻量化 铝合金 有限元方法

Abstract

In life, people's passenger cars are becoming lighter and lighter under the condition of constant horsepower. This is the intent of the designers to do so, and there are many purposes, but the main purpose is to make passengers more comfortable without affecting operational and safety. This topic chooses the independent sub frame of a certain car, and uses aluminum alloy to replace the steel way to design, so as to achieve the purpose of reducing weight. Firstly, the independent sub frame is analyzed, and the basic idea of the independent sub frame is established. Then the three-dimensional model is established by the measurement data. The three-dimensional model is transformed into a finite element analysis model by the learning software. The finite element analysis software, such as ANSYS, is used to analyze the strength analysis of the independent sub frame after the replacement of the aluminum alloy material. Whether it is feasible.

Before we do research, we should make clear the purpose and method of lightweight design of sub frame. Specifically, we need to read the literature to understand the history of the sub frame, to study the reasons for its emergence and its significance in the automobile industry. And understand the function of the sub frame once through history, and finally learn how to design the sub frame. We should also study the structural characteristics, materials, types and connection ways of the sub frame. All these need to be based on reading literature. This topic is optimized by means of aluminum alloy replacement. Therefore, aluminum alloy is also studied in the paper, and the development of aluminum alloy in automobile manufacturing is described.

After that, we must prepare for the finite element analysis. First, a load condition is selected to analyze the strength of the sub frame. The load and boundary conditions are calculated. In order to carry out finite element analysis, we need to learn the use of auxiliary software. Here we use ANSYS. The finite element analysis software Ansys can be used to simplify the three-dimensional model of the independent sub frame. The grid is divided, rigid connection and load condition are applied, and the finite element analysis model of independent sub frame is established.

The research work of this subject has referenced the development of modern automobile, and also provided reference for the development of modern automobile industry.

In the study of the current situation at home and abroad, I know the material science of aluminum alloy, our strength is still relatively weak, can not be compared with the big countries in the world, the progress in material science can only be obtained through one time and another experiment, and our country lost too much in the first half of the last century, a slow step, and the distance from the world. There is a big gap between them, and there is a distance from other traditional powers. Fortunately, in recent years, our country's economy has risen, and every year the researchers are also increasing step by step. These have provided a convenient development for our basic disciplines. In spite of the failure to see the results for a moment, with the bonus of the huge scientific research population and the economy, China is bound to make great progress. In the coming decades, I believe that human beings are bound to move towards the sea of stars, and there are these ordinary basic disciplines in that ship's ticket. As an ordinary mortal, I am at the crossroads of the world, and I must strive hard to dedicate every strength to myself. Since the founding of the people's Republic of China, many predecessors have gone to the future before they have this beautiful land.

In the design of this half year's paper, I learned to combine knowledge and application, understand the truth of knowledge and practice, and master many of the knowledge that I have not in the class in the course of studying. Through this practice, I understand that the hard won research work has aroused my interest in scientific research, but I know my shortcomings, I regret that I do not concentrate on studying in my college career, and then work in the aftermath, and I will also want to start the charge in the case of scientific research.

Keywords: Independent Suspension; Lightweight design;Aluminium alloy; finite element analysis

1. 绪论
   1. 概述

如果说汽车是人的话，那么毫无疑问车架就是“人”的骨架。副车架作为车身的一部分，起到了连接车桥，悬挂的作用，他们在通过副车架与车辆的“骨架”相连。为汽车设计副架的目标是是阻隔振动和噪声，减少其直接进入车厢，因此成本会提高，所以副车架大多出现在豪华的轿车和越野车上，一些汽车为了更极致的舒适性还为引擎装上副架。普通车辆没有副车架，其承载体悬挂与车身钢板直接连接。因此，前后桥的悬架和摇杆机构都是离散的部件，不是装配。汽车的悬挂系统可以与副车架相连，再有副车架间接连接到车身。

• 1. 课题研究目的和意义

汽车的底盘是汽车的基础，就仿佛是人体的骨架。人对汽车的操纵要通过底盘传导，底盘关系着操纵性，同时汽车车轮所受的力也是通过底盘传递到座椅上，在传递到人身上，底盘影响着舒适性。传统底盘只能向一方考虑，因此为了操纵性而不可避免的放弃了舒适性，倘若过于注重乘员乘坐的体验而忽视了操纵性，这对于安全有着很大的影响。所以为了在悬挂系统上平衡舒适性和操控性，设计师们设计了一些复杂结构来实现二者的平衡。这些复杂结构有的成功有的失败，而这些复杂结构中作用最为显著的就包括了副车架。相比于传统汽车，现代轿车通常将悬挂系统集成在金属环上，而不是与车身直连，这种环装的组件我们通常称之为轿车的副车架。使用副车架的汽车相比传统汽车就不免要重上许多，这又会带来更多的油耗和污染。课题的目的是通过将副车架材料替换为铝合金，有效减轻车身质量，提高经济性和环保。同时，汽车轻量化也会带来碰撞安全性的提升。