【作者】 唐亮；

【导师】 杨昌棋；

【作者基本信息】 重庆大学 ， 固体力学， 2011， 博士

【摘要】 力学试验,作为力学学科的重要研究手段和组成部分,始终以从被试对象或现象中获取并提炼能够反映其客观现象本质的信息为终极目标。力学现象本质信息的提取过程就是一个在繁杂力学环境中去伪存真,去粗取精的过程。力学试验的成败则取决于力学信息获取的手段和方法、力学信息的表征、力学信息的分析与应用以及试验过程中的人为因素。随着社会经济和科学技术的飞速发展,一方面,力学试验涉及领域快速扩展,复杂程度不断提升。另一方面,研究与工程实际的需求对试验精度和实验数据的可靠性不断的提出新的挑战。如何在实验中提高测试精度,改进和创新测试方法,从而有效减少和消除来自整个测试过程的误差和失误还有众多问题亟待解决。特别是在多因素作用下的复杂力学量传感和测试、测量信息的不确定度控制以及有效信息的加工与应用是一项具有极强科学意义和现实意义的工作。本文以力学测量综合误差控制和力学信息的提取与应用为主线,对金属材料力学性能测试中的变形测试精度问题、高拉扭比复合载荷作用下的多维力传感器设计问题,生物力学中本构实验现存的若干困难的应对方法以及“部件”层次的各种力学量测试的方法,基于力学特征量采集与识别方法等若干多因素作用下力学量传感与测量问题进行了广泛的探讨。具体的工作和成果包括:①探讨了力学测试技术中最重要的两个被测量:力和变形量的传感及测试方法。对在标准试验中最常用的电阻应变式变形传感器——电子引伸计的设计与制造,特别是弹性体及传感臂在结构的设计和材料的选择上作了深入的分析。为了消除试验中偏心拉伸所带来的影响,设计了一种高精度的双侧电子引伸计。同时利用理论分析以及有限元数值模拟方法,系统地研究了在金属标准拉伸实验中,上下夹具偏心对变形测量结果带来的影响,并对变形测量中出现的变形值“反走”这一特殊的现象出现的机理做出了分析与验证。②针对薄壁微管拉扭试验中载荷测量的特殊需求,研制了一种基于薄梁拉——弯变形的对称一体化结构的高拉扭载荷比复合式传感器,解决了拉扭传感器在这一特殊应用下诸多精度问题,满足了试验要求,为类似的高拉扭比载荷传感器的设计提供了具有参考价值的设计实例。③在生物力学交叉学科中的实验领域,针对生物软组织在本构实验中分层分束,含水性高,常规夹持易受损等问题,设计了一种适用于生物软组织材料的冷冻夹持夹具,并结合所设计的膝关节前交叉韧带的分束张力测量的部件试验,实践了混合数值——实验的材料参数反推识别方法,在生物材料的参数获取和修正上取得了良好的效果。④面向生物识别领域设计了一种基于“力感知”键盘的力学特征量的生物学特征识别方法,这种方法利用了人员的击键施力行为,结合按键力度力学特征量的传感、采集以及特征数据的存储等,进而对力学特征信号的时变特征采用曲线形态特征判别分析的方法,对不同人员之间以及同一人员在不同状态下的施力行为进行了识别。文章最后对本文工作进行了总结和展望,提出了几个可深入研究的方向。更多还原

【Abstract】 Mechanical testing is an important research means and components of mechanical discipline. The final goal is to obtain and extract information which can reflect the nature of the test subject or phenomenon. The extration of mechanical phenomenon nature is a process from complex mechanical environment. The success of the mechanical test depends on the means and methods of mechanical information, the characterization of mechanical information, the analysis and application of mechanical information and human factors during the test.With the rapid develoment of socio-economic and scientific technology, on the one hand, the areas and complexity of mechanical tests are increasing rapidly. On the other hand, the research and engineering requires much more accuracy and reliability of experiment. There are many issues to be resolved such as improvement the precision of the expriment and the testing methods. And effectively reduce and eliminate errors from the entire testing process. It is a very scientific and pratical study including complex mechanical quantity sensing and testing, uncertainty of measurement controling and effective information application.In this paper, the research follows the integrated error control and information extraction and application of mechanical testing. The paper researches deep into the precision of the deformation test methods; the design of special torsion/tension load cell; constitutive experimental and mechanical quantity testing of biomechanics; mechanical quantities feature recognition and so on. The detailed work and outcomes are as following:①It discussed the two most important measured quantities of mechanical testing techniques: force and deformation. And a deep analysis carried out for the most common strain of a deformation sensor in the standard test - electronic extensometer, particularly in the choice of materials and the design of structure. In order to eliminate the impact of the eccentric tensile, a two-side high-precision electronic extensometer was designed. At the same time, the impact of upper and lower clamp’s offset to deformation was systematic studied by using theoretical analysis and finite element method in the metal standard tensile test. The reversal phenomenon of electronic extensometer was analyzed and verified.②A load cell with large ratio of tensile traction to torque is developed for biaxial tension-torsion test of thin-walled microtubes, which is based on the separation of tensile / bending deformation of 4 symmetrically distributed thin strips, on each of which there is a hole in the middle. It solve a lot of problems in this particular application, and meet the need of test requirements. It provides a valuable example for similar sensor design of low-torque / high-tensile.③The biological soft tissue is delamination and multi-bundle fasciculi, high water content, easily damaged by conventional clamping. Aiming at the problems of bio-mechanics constitutive experiment, a freezing clamp was designed for the biological soft tissue. Combining the anterior cruciate ligament tension measurement experiment, a mixed numerical-experimental method for identify the constitutive parameters was carried out. A good result was achieved in parameters acquisition and correction.④A new mechanical characteristics recognition method of biological feature was designed. It uses the keystroke actions, combined with the sense of keystroke mechanical characteristics, data acquisition and features storage. The time-varying characteristics of the signal intensity were analyzed by morphological characteristics curve analysis method. The identification between different people and different states of keystroke behavior was put in practice.更多还原