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动态法测定材料的杨氏模量 总被引:4,自引:0,他引:4
1 前言用静态拉伸法测定杨氏模量的方法因其本身诸多的缺点在发达国家自 2 0世纪 80年代起已被动力学弹性模量测定方法所代替 ,动力学方法也是我国国家技术标准GB T2 10 5— 91、GB2 10 5— 80所推荐的方法 .该方法能准确反映材料在微小形变时的物理性能 ,测得值精确稳定 ,对脆性材料 (如石墨、陶瓷 )也能测定 .该法测定的温度范围极广 ,从液氮温度—室温— 1,0 0 0℃~ 2 ,6 0 0℃内均可 .本文著者黄亦明(高级工程师 )于 195 9— 1976年在中国科学院工作期间 ,承担了国家正式下达的“高温热物理性能测试基地的建立和发展”项目 ,专门… 相似文献
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用原子吸收光谱法对大马士革玫瑰枝、叶中Ca、Mg、Fe、Cu、Mn 5种微量元素的含量进行了测定,并研究了不同生理条件、不同器官中5种元素含量的动态变化规律。结果表明:大马士革玫瑰枝叶中含有丰富的Ca、Mg、Fe、Cu、Mn微量元素,元素含量高低顺序依次为:Ca>Mg>Fe>Mn>Cu;玫瑰叶片中的微量元素含量均明显高于枝条,甚至较枝条要高出一个数量级以上;未开花植株和开花植株微量元素含量的动态变化规律总体上基本相似,但是未开花植株的微量元素含量要显著低于开花植株;在生长季节内,5种微量元素含量各呈现不同的动态变化规律,这与植物的生长发育和元素的植物生理功能密切相关。 相似文献
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一固体作品在受到功率为W的热源加热时,其温度T与加热时间t之间呈负指数函数关系.由所得的这一T-t关系可进一步求得计算该固体样品比热容的表达式.据此设计了适用于普通物理实验的测定固体比热容的新方法──动态法.由实验绘出的动态E-t曲线求得团体比热容. 相似文献
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介绍了用声速测量仪来测定固体的杨氏模量,并与教材中介绍的动态悬挂法测定固体的杨氏模量进行实验比较,结果更加简单、误差更小,并能一机多用。 相似文献
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Naseem Akhter Hyun-Chul Jung Ho-Seob Chang Kyeong-Suk Kim 《Optics & Laser Technology》2009,41(5):526-529
This paper proposes a sonic resonance test for an elastic modulus measurement which is based on the electronic speckle pattern interferometry. Previous measurement technique of elastic constant has the limitation of application for thin film or polymer material because contact to specimen affects the result. It has been developed as a non-contact optical measurement technique which can visualize resonance vibration mode shapes with whole field. The maximum vibration amplitude at each vibration mode shape is a clue to find the resonance frequencies. The dynamic elastic constant of test material can be easily determined from vibration of a beam equation using the measured resonance frequencies. The proposed technique is able to give high accurate elastic modulus of materials through a simple experimental set-up and analysis. The experimental result also compared to the theoretical result. 相似文献
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The paper proposes an evaluation technique for the elastic modulus of a cantilever beam by vibration analysis based on time average electronic speckle pattern interferometry (TA-ESPI) and Euler-Bernoulli equation. General approaches for the measurement of elastic modulus of a thin film are the Nano indentation test, Buldge test, Micro-tensile test, and so on. They each have strength and weakness in the preparation of the test specimen and the analysis of experimental results. ESPI is a type of laser speckle interferometry technique offering non-contact, high-resolution and whole-field measurement. The technique is a common measurement method for vibration mode visualization and surface displacement. Whole-field vibration mode shape (surface displacement distribution) at resonance frequency can be visualized by ESPI. And the maximum surface displacement distribution from ESPI can be used to find the resonance frequency for each vibration mode shape. And the elastic modules of a test material can be easily estimated from the measured resonance frequency and Euler-Bernoulli equation. The TA-ESPI vibration analysis technique can be used to find the elastic modulus of a material requiring simple preparation process and analysis. 相似文献
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在共振法测量杨氏模量实验中,为了获得更精确的共振频率,使用基于声卡的虚拟信号发生器代替FB209动态杨氏模量测试仪,用虚拟示波器代替普通示波器,提高了测量信号的精度,帮助学生更好地理解和掌握实验. 相似文献
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主要介绍了根据动态法测量原理设计的新型杨氏模量自动测量仪,此仪器创新性地采用全自动扫频技术,实现了金属材料杨氏模量的全自动测量,并且增加了虚假共振的判断和品质因素的测量,提高了测量结果的可靠性. 相似文献
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采用理论计算与动高压实验相结合的方法,提出了一个计算剪切模量温度系数G′T的新方法.首先用理论方法计算一个中间数据G(PS),然后再与动高压实验数据G(PH)结合在一起计算出G′T,并针对93钨合金材料进行了计算.计算结果表明剪切模量温度系数G′T开始是随温度和压力变化的,但在高温高压下,它趋近于一常数.对于93钨合金,这个常数约为-004GPa/℃.同时,这也是对Steinberg本构模型中的剪切模量温度系数为常数的一个证明.并且,当把这一常数代入剪切模量温度系数的计算式中,将重新计算出的剪切模量与实验测得的剪切模量结果进行了比较,结果表明二者符合得很好,从而证明了本计算的剪切模量温度系数的正确性.
关键词:
有限应变物态方程
剪切模量温度系数
Steinberg本构模型
动高压实验 相似文献
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Pulse wave velocity (PWV) is widely used for estimating the stiffness of an artery. PWV is an average measurement of artery stiffness between two measuring sites. From measured PWV, the diameter and thickness are needed to calculate the elastic modulus of the artery. In this paper a new method of using ring resonant mode for estimation of arterial elastic modulus is proposed. To generate the ring resonance, a localized radiation force of ultrasound is remotely and non-invasively applied at the artery. The vibration response of the artery is measured by optical techniques. Three ring resonant modes are identified for estimation of the elastic modulus. The viscoelasticity and the complex modulus of the artery can be obtained. Experiments were carried out on a porcine artery embedded in gelatin. The estimation only requires the diameter of the artery, but does not need the thickness of the artery which is difficult to measure with accuracy and precision. 相似文献
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The first measurements of the tensile elastic modulus of polypyrrole nanotubes are presented. The nanotubes were mechanically tested in three points bending using atomic force microscopy. The elastic tensile modulus was deduced from force-curve measurements on different nanotubes with outer diameter ranging between 35 and 160 nm. It is shown that the elastic modulus strongly increases when the thickness or outer diameter of polypyrrole nanotubes decreases. 相似文献
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对动力学法测定材料弹性模量实验的研究 总被引:2,自引:0,他引:2
简要分析了动力学法测定材料弹性模量实验在理论推导中存在的困难,讨论了实验中悬丝的材料、直径等影响因素,并提出相关建议;同时对利用李萨如图形判断共振频率的方法做了介绍和说明. 相似文献
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根据压电陶瓷晶体压电原理、压电陶瓷棒和试样横振动原理,分析了动态杨氏模量实验中出现的多个谐振频率,理论分析与实验结果吻合. 相似文献