汽车车身冲压钢板高周疲劳试验研究

发布时间：2018-07-12 18:19

本文选题：车身冲压钢板 + 单向拉伸试验　；参考：《河北工程大学》2017年硕士论文

【摘要】：随着社会的不断进步,各种材料都被应用于工程建设当中,但钢铁材料始终占据着主要位置,其应用广泛,需求量大,也很经济。但所有材料都避免不了破坏失效,而疲劳破坏是工程材料当中失效很常见的一种形式。在汽车制造行业当中,汽车的轻量化已经成为一种新的发展趋势,对选用的制造材料变得很关键,不仅要可以满足汽车的轻量化要求,而且还要保证其应有足够的强度与刚度。除汽车行业,包括其他工程领域,疲劳破坏已然成为一种带来人身事故和经济损失的重大原因,所以对材料构件的疲劳耐久性成为必须要考虑的因素。本文介绍了汽车车身常用钢材的种类,以及其疲劳耐久性能的研究现状。对疲劳过程和机理以及影响疲劳强度的主要因素作了详细阐述,重点对获取材料疲劳性能的试验方法进行了介绍。汽车通常在行驶时其所受的应力水平较低,经过较久时间的积累才会引起疲劳失效。在研究汽车车身材料的疲劳性能时,采用应力与疲劳寿命之间的关系来表示其疲劳特性。本文通过对汽车车身所选冲压钢板进行高周疲劳试验,试验内容及方法按照GB/T 26076—2010《金属薄板(带)轴向力控制疲劳试验方法》制定,试验设备采用美国MTS Landmark电液伺服疲劳试验机。整个疲劳试验研究包括:材料的单向拉伸试验,高周疲劳试验,数据的分析,S-N曲线的拟合以及设计S-N曲线的获取。试验通过小样本量中值试验法,施加非对称的轴向正弦波载荷,获取材料在不同应力水平下的循环寿命,对获取的大量试验数据分析,通过最小二乘法拟合曲线,得到疲劳极限。由于数据存在的分散性,选择合适的置信区间,统计分析得到合适的设计S-N曲线。
[Abstract]:With the development of society, all kinds of materials have been used in engineering construction, but the steel material has always occupied the main position, its application is extensive, the demand is large, and it is also very economical. But all materials can not avoid failure, and fatigue failure is a common form of failure in engineering materials. In the automobile manufacturing industry, the lightweight of the automobile has become a new development trend, which is very important to the selected manufacturing materials, not only to meet the lightweight requirements of the automobile, but also to ensure that it should have sufficient strength and stiffness. In addition to automobile industry, including other engineering fields, fatigue damage has become a major cause of personal accidents and economic losses, so the fatigue durability of material components must be considered. This paper introduces the kinds of steel used in automobile body and the research status of its fatigue durability. The fatigue process and mechanism as well as the main factors affecting fatigue strength are described in detail, and the test methods for obtaining fatigue properties of materials are introduced emphatically. The stress level of a vehicle is usually low when it is driven, and fatigue failure will only occur after a long time accumulation. The relationship between stress and fatigue life is used to express the fatigue characteristics of automobile body materials. In this paper, the high cycle fatigue test of stamping steel plate selected for automobile body is carried out, and the test contents and methods are formulated according to GB/ T26076-2010 < method of axial force control fatigue test for sheet metal (belt). MTS Landmark electro-hydraulic servo fatigue testing machine is used in the test equipment. The whole fatigue test includes uniaxial tensile test, high cycle fatigue test, analysis of data, fitting of S-N curve and acquisition of design S-N curve. The cyclic life of materials under different stress levels is obtained by applying asymmetric axial sinusoidal load through the method of small sample size median test. A large number of test data obtained are analyzed and the curve is fitted by the least square method. The fatigue limit is obtained. Due to the dispersion of the data, a suitable design S-N curve is obtained by statistical analysis by selecting the appropriate confidence interval.
【学位授予单位】：河北工程大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U465.11;TG142.15

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