材料力学性能原位扭转测试装置的设计分析与试验研究

发布时间：2018-11-24 20:39

【摘要】：材料科技的发展加快了人类社会前进的步伐，各种新材料的开发与应用给人类的生产生活带来了极大的便利，但随着对材料的使用要求不断提高，人们同时受到了由于材料失效带来的各种问题的困扰，如何更加全面深入的认识材料、评价材料，成了科技界和工程界面临的巨大挑战。传统的材料力学测试手段仅能从若干力学参数出发对材料进行评价，难以深入揭示材料的微观变形损伤机制，，在材料科技日益发展的今天已无法满足人们的测试需求。材料微观力学性能原位测试技术在具备传统测试手段所具备的功能的同时，还可以实现在载荷作用下对材料微观变形损伤机制与微观组织演化等特性进行动态原位观测，对深入研究材料的宏观力学行为与微观组织结构演化规律具有深远的意义。本文对当前商业化的材料扭转测试设备和原位监测技术的国内外发展现状和趋势进行了较为深入的综述和分析，在此基础上，结合目前材料扭转原位测试技术领域尚属空白的现状，设计提出了一种可与光学显微成像设备相兼容的原位扭转测试装置，为研究扭转载荷作用下材料的微观变形行为和损伤机制提供了新颖的测试手段。论文对原位扭转测试装置进行了整体方案设计，对装置主要机械元件的强度、刚度、疲劳寿命等进行了计算与分析，对高速运动元件和装置整机进行了模态分析，确保了测试装置在服役期间可以正常工作；同时对测试装置电控系统的数据采集与控制方案进行了介绍。在上述工作的基础上，论文对扭转测试装置的载荷及转角误差来源进行了分析，并利用激光测距仪对转角误差进行了实际测量，确定了测量转角和实际转角之间的关系；同时提出了试件圆弧过渡区域的等效处理算法，并在此基础上提出了剪切模量的修正算法；对常用材料的扭转测试结果表明修正算法具有良好的适用性。利用自制的测试装置，本文对2A12铝和H59黄铜在循环扭转载荷下的力学行为进行了研究，两种材料在循环扭转载荷下均表现出了明显的包辛格效应，通过与单向扭转试验对比发现：两种材料的抗扭强度并未有明显改变；对Q235热轧钢和Q235冷拉钢进行了扭转力学测试，结果表明在冷拉工艺下Q235钢的扭转屈服强度有了大幅提升，但两种成型工艺下材料的抗扭强度差异较小。最后，论文还将装置与奥林巴斯BXFM显微镜结合，对H59黄铜和Q235钢在扭转载荷下的微观形貌和金相组织进行了原位观测试验，验证了测试装置的原位测试能力。
[Abstract]:The development of material science and technology accelerates the progress of human society. The development and application of various new materials bring great convenience to the production and life of human beings, but with the increasing requirements for the use of materials, At the same time, people are troubled by various problems caused by the failure of materials. How to understand and evaluate materials more comprehensively and deeply has become a great challenge to the scientific and engineering circles. The traditional testing method of material mechanics can only evaluate the material from a number of mechanical parameters, and it is difficult to reveal the microscopic deformation damage mechanism of the material in depth. With the development of material science and technology, it is unable to meet the testing needs of people. The in-situ testing technique of material micromechanical properties can not only have the function of traditional testing methods, but also realize the dynamic in-situ observation of the damage mechanism and microstructure evolution of materials under load. It is of great significance to study the macroscopic mechanical behavior and microstructure evolution of materials. In this paper, the domestic and international development status and trend of commercial material torsion testing equipment and in-situ monitoring technology are summarized and analyzed. According to the blank situation in the field of material torsion in-situ testing, a kind of in-situ torsion testing device which is compatible with optical microscopic imaging equipment is designed. It provides a novel method for studying the microscopic deformation behavior and damage mechanism of materials under torsional loading. In this paper, the overall scheme of in-situ torsion testing device is designed, the strength, stiffness and fatigue life of the main mechanical components of the device are calculated and analyzed, and the modal analysis of the high-speed moving elements and the whole machine is carried out. Ensure that the test device works properly during service; At the same time, the data acquisition and control scheme of the electronic control system of the test device is introduced. On the basis of the above work, the paper analyzes the load and angle error source of the torsion measuring device, and uses the laser rangefinder to measure the rotation angle error, and determines the relationship between the measured rotation angle and the actual rotation angle. At the same time, the equivalent processing algorithm for the arc transition region of the specimen is proposed, and on this basis, the shear modulus correction algorithm is proposed, and the torsional test results of common materials show that the modified algorithm has good applicability. In this paper, the mechanical behavior of 2A12 aluminum and H59 brass under cyclic torsional load is studied by using a self-made testing device. Both materials exhibit obvious Bauschinger effect under cyclic torsional load. Compared with the unidirectional torsion test, it is found that the torsional strength of the two materials has not changed obviously. The torsional mechanical tests of Q235 hot rolled steel and Q235 cold drawn steel show that the torsional yield strength of Q235 steel has been greatly improved under cold drawing process, but the difference of torsional strength between the two molding processes is small. Finally, the in-situ observation of the microstructure and microstructure of H59 brass and Q235 steel under torsional load was carried out by combining the apparatus with Olympus BXFM microscope. The in-situ testing capability of the apparatus was verified.
【学位授予单位】：吉林大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TH87

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