轻量化复合材料座椅骨架设计毕业论文
2021-04-19 00:23:52
摘 要
近些年以来,交通事故一直是人们口中的热议话题,人们也越来越重视汽车的安全性,各国的法令法规中安全规章制度也欲趋于全面与严格,以此来约束汽车的生产和制造标准。同时,面对着资源与环境这对天然矛盾,节能减排的号召也日渐强烈,汽车的轻量化随即孕育而生。现代汽车工程聚焦于如何在满足以安全性为大前提的条件下,来实现汽车车体的轻量化。
汽车可轻量化的部件并不占少数。悉数纷繁复杂的汽车结构件中,座椅是为数不多的在汽车整体构造当中直接与人体相接触的部件,直接影响到车内乘员的乘坐的舒适度和安全性,人们的关注点便自然偏向于汽车座椅的研究,各国更是相继推出了与其相关的座椅安全法规,目的莫过于保护车内乘员的安全。同时,座椅整体结构是影响车体质量重要组成部分,故座椅的轻量化设计也成为各大汽车厂商关注的重点之一。
现阶段轻量化汽车骨架共有两种设计的思路。一则是设计轻量化骨架,即通过优化结构设计,得到重量最小的座椅骨架;二则是采用轻量化材料,既可用密度较轻的合金材料(如铝合金和镁合金等,通过压铸或冲压工艺,制造座椅坐垫骨架或者靠背骨架),也可以采用复合材料(如高强度塑料、长纤维、碳纤维)。
本文主要针对前排座椅骨架结构,设计并分析最初座椅结构,导入CAD并完成平面三视图的绘制,随后在Catia中建立座椅骨架的碳纤维替代模型,同时应用有限元仿真技术,在Ansys中完成静态实验和动态试验的模拟,进行强度与刚度的校核,验证碳纤维替代传统钢材的可行性。其中,静态实验依据GB 15083模拟靠背轻载强度试验,而动态试验则依据 GB15083-2006 中与汽车座椅相关的法规标准进行台车试验模拟,即对该座椅骨架结构进行抗行李冲击台车试验仿真模拟。
对于未达到法规标准的模型,在保证轻量化的前提之下,通过增加部分板料厚度达到预期的强度刚度,从而论证碳纤维复合材料替代钢材实现材料轻量化的可行性。
关键词:轻量化、碳纤维、传统座椅骨架结构分析、碳纤维模型、静态分析
Abstract
In recent years, traffic accidents have always been a topic of heated discussion among people. People also pay more and more attention to the safety of automobiles. The safety regulations and rules in laws and regulations in various countries also tend to be comprehensive and strict, so as to restrict the production of automobiles. And manufacturing standards. At the same time, in the face of the natural contradiction between resources and the environment, the call for energy conservation and emission reduction has become increasingly strong, and the weight of automobiles has emerged. Modern automotive engineering focuses on how to achieve lightweighting of automotive bodies under conditions that satisfy safety.
Parts that are lightweight in cars are not in the minority. Among the numerous complicated automobile structural parts, seats are one of the few parts that directly contact with the human body in the overall structure of the automobile, directly affecting the ride comfort and safety of the occupants in the vehicle, and people's attention will be naturally In favor of research on car seats, countries have successively introduced their related seat safety regulations, which are aimed at protecting the safety of passengers in the car. At the same time, the overall structure of the seat is an important component that affects the quality of the car body. Therefore, the lightweight design of the seat has also become one of the focuses of the major car manufacturers.
At this stage, there are two design ideas for lightweight car skeletons. One is to design a lightweight skeleton, that is, to optimize the structural design to obtain the smallest weight of the seat skeleton; the other is to use lightweight materials, which can use lighter alloy materials (such as aluminum alloys and magnesium alloys, etc.) by die-casting or Stamping process to manufacture seat cushion frame or backrest frame, composite material (such as high-strength plastic, long fiber, carbon fiber) can also be used.
This article focuses on the front seat frame structure, design and analysis of the original seat structure, import CAD and complete the plane of the three-view drawing, and then in Catia in the establishment of carbon skeleton replacement model of the seat frame, while applying finite element simulation technology, in Ansys The simulation of static and dynamic tests was completed, and the strength and stiffness were checked to verify the feasibility of replacing the traditional steel with carbon fiber. Among them, the static test is based on GB 15083 simulation of the light load strength test of the backrest, and the dynamic test is based on GB 15083-2006 car seat related regulations and standards for the trolley test simulation, that is, the anti-baggage impact of the seat frame structure of the trolley Test Simulation.
For models that do not meet regulatory standards, under the premise of ensuring light weight, by increasing the thickness of some sheets to achieve the desired strength and stiffness, the feasibility of using carbon fiber composites to replace steel materials to achieve lightweight materials is demonstrated.
Key words: lightweight;carbon fiber; traditional seat skeleton structure analysis;carbon fiber model;static analysis
目录
第1章 绪论 1
1.1 前言 1
1.2碳纤维介绍 1
1.3国内外的研究状况分析 2
第2章 传统座椅骨架设计与分析 4
2.1 座椅骨架整体造型说明 4
2.2 本次传统座椅骨架结构件介绍 4
2.3本次传统座椅骨架功能件介绍 5
2.3.1头枕调节件及挂件 5
2.3.2调角器 8
2.3.3滑轨 10
2.4 本章小结 11
第3章 轻量化座椅骨架设计与验证 12
3.1碳纤维复合材料座椅骨架模型的建立 12
3.2碳纤维复合材料座椅骨架的可行性研究 12
3.2.1Ansys功能简介 13
3.2.2座椅系统试验简介 13
3.2.3材料替代模型的前处理 13
3.2.4碳纤维复合材料座椅的静态模拟 15
3.3本章小结 17
第4章 结论及展望 18
4.1 论文总结 18
4.2 工作展望 18
参考文献 19
致谢 20
第1章 绪论
1.1 前言
近年来,汽车工业蓬勃发展,全球汽车保有量急剧增长,由此产生的能源和环境污染问题凸显。为了应对这些问题,欧洲经济委员会 ( ECE) 和欧盟于 1992 年正式颁布了汽车排放指令。随后,我国也制定了 《乘用车燃料消耗量评价方法及指标》标准 ( GB27999-2011) 。这些法令的颁布,极大地限制了汽车制造商的发展。有研究表明: 一辆轿车的质量若能减少 10% ,则其燃油经济性可提高 3% ~ 4% ,同时汽车的排放量也会相应降低1% - 3%。因而,为满足相关的排放法规不少商家都乐意通过汽车轻量化的手段。
对于汽车轻量化,按照汽车的总体构造大致上可以分为 4 类: 汽车车身、发动机、汽车的内外装饰件,还有就是汽车底盘。由于汽车内外饰件相对较好的受力条件及工况,其轻量化实现起来相对容易,受到了广大汽车制造商的关注。作为汽车内外饰件中最大的零部件之一的汽车座椅,在满足舒适性、安全性和美观性的条件下,如何制作得更加轻盈自然而然地成了广大汽车制造商的追求。纵观汽车座椅,无非是由由骨架、缓冲件和其他功能件来组成。对于整椅质量来说,骨架占 60% ~ 70% ,泡沫占 9% ~12% 、面料占 7% ~ 12% ,塑料件占 5% ,而其他辅助的功能件则占到 9% 。很显然,座椅骨架在整椅中质量占比最大,因此,减轻座椅骨架的质量,可以有效地实现整椅轻量化。自 20世纪 90 年代以来,陆续有一些学者和研究机构开始了汽车座椅骨架轻量化的研究。然而,由于国内汽车座椅的研发起步较晚,许多研究仅限于对座椅骨架一些过设计结构进行改进和优化,并未对整椅骨架轻量化进行深入的研究。因此,汽车座椅骨架轻量化的研究有着重要的理论意义和实际应用价值。
1.2碳纤维介绍
碳纤维主要是指大多由碳元素组成的一种复合型纤维性材料,其分类主要是依据碳含量的多与少,但总体而言其中玩的含量在90%以上。因为构成的主要元素为碳,碳纤维具有类似一般碳素材料的相同属性特性,例如:耐高温、耐摩擦、良好的导电性、导热及较强的耐腐蚀等,但与一般碳素材料所不同的地方则是,他是各向异性材料,外形较为柔软、容易加工成各种织物,各向异性体现在当沿纤维轴方向时材料本身表现出很高的强度。碳纤维很高的比强度,密度较小。
碳纤维是一种力学性能优异的新型材料,它的密度还不到钢的1/4,由碳纤维做成的碳纤维树脂复合材料抗拉强度却一般都在3500Mpa以上,大约是钢的抗拉强度的7~9倍,抗拉弹性模量为23000~43000Mpa,这也是高于钢。