共查询到19条相似文献,搜索用时 431 毫秒
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20世纪90年代Singh等人建立了基于非静水压缩的晶格应变理论。这一理论的建立使非静水压环境下状态方程的精确测量成为可能,同时也开辟了材料弹性常数测量的新方法。目前,这一理论在材料状态方程研究、强度研究、弹性研究和实验数据分析诸多领域有着广泛的应用。文中主要介绍晶格应变理论及其应用,并简要介绍我们利用晶格应变理论对高压下NiO弹性性质的研究结果。 相似文献
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声弹性方法测量金属材料的塑性损伤 总被引:3,自引:0,他引:3
本文提出一个利用非线性参数研究材料损伤的声弹性方法.在该方法中定义了一个由二阶和三阶弹性常数所组合的损伤变量.以20#钢为例,采用横波声弹性方法测量金属材料的塑性损伤.同时用声速法作了损伤测量.对比两种方法的实验结果表明,新方法是对金属材料塑性损伤测量的有效技术. 相似文献
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定向结晶合金材料全部工程弹性常数的超声测定 总被引:2,自引:0,他引:2
采用超声脉冲回波重合法(PulseEchoOverlap)对一种定向结晶耐高温合金材料进行了研究,精确测试了该材料中沿不同方向传播的超声纵波及横波的声速,计算出慢度曲线,并确定了材料的全部工程弹性常数.通过对工程弹性常数及慢度曲线对材料进行评价,为其工程应用提供重要依据 相似文献
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本文介绍了进行三维应力分析的全息光弹性方法及有关技术,分析了全息光弹性方法的主要困难在于冻结材料的应力光学常数比B/A接近-0.5,并提供了一种新的光弹性材料制作和冻结工艺。这种材料冻结时的应力光学常数比可以远离-0.5。用这种材料制成的三维模型,可以通过全息光弹性方法获得三维应力的全应力实验解答。用这种方法测定了对径受压圆球和高压压头对称断面上的应力分布。实验结果和理论解进行了比较。 相似文献
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黄炎;李种复;杨光松 《力学与实践》1986,8(3):30-32
用复合材料制成的工程结构由于制造工艺复杂,其材料的弹性常数与标准试件的弹性常数相差很大,Kavanagh采用一次测试法对结构物直接进行多点测试来确定材料的弹性常数同时对结构进行应力分析、本文对玻璃钢迴转壳结构采用直接测试法确定材料的弹性常数然后进行应力分析。 相似文献
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当前,光学引伸计虽然应用较为广泛,但仍然存在泊松比测量精度不高的不足,主要原因是难以同时获得具有高精度的轴向应变与横向应变.因此,本文提出将基于双向视场分离技术的远心光学引伸计应用到材料泊松比测量中.利用该引伸计,可以同时采集试件两个方向四个视场的表面信息;通过测得的双向应变—荷载曲线,得到准确的材料泊松比和弹性模量.基于该引伸计,开展了水泥试件压缩试验、不锈钢试件与环氧树脂试件拉伸试验,分别得到试件的弹性模量与泊松比.结果表明:与电测法的数据对比,该引伸计具有较高精度与较好稳定性的特点,在准确测量材料弹性常数方面具有广泛的应用前景. 相似文献
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压电传感器和致动器都可以看成是一种复合材料层合板结构,由压电材料层和非压电(弹性)材料层交替铺设而成。对于这类任意铺设的层合板悬臂梁结构,我们推导出了表示力学变形与外加电场之间耦合效应的解析表达式。进而,又推导出了两类(一类为单层压电-弹性层,另一类为双层压电-弹性层)层合型悬臂梁结构机电耦合性能的解析公式。在该机电耦合模型中,包括了两个压电常数d211和d222。此外,还建立了含压电材料的有限元算式,进行了实验测量。最后,通过比较解析解(包括考虑了d222参数的理论值和没有考虑d222参数的理论值),实验值以及有限元计算结果,发现它们吻合得很好,而且考虑d222是十分必要的。 相似文献
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Dynamic contact stiffness at the interface between a vibrating rigid sphere and a semi-infinite transversely isotropic viscoelastic solid is investigated. An oscillating force superimposed onto a static compressive force in the vertical direction excites the vibration of a rigid sphere, which causes variable contact radius and contact pressure distribution in the contact region. The assumption of a sufficiently small oscillating force yields a dynamic contact-pressure distribution of a constant contact radius, which gives dynamic contact stiffness at the interface between the rigid sphere and the semi-infinite solid. Numerical calculations show the influence of vibration frequency of the sphere, and elastic constants of the transversely isotropic solid on dynamic contact stiffness, which benefits quantitative evaluation of elastic constants and orientation of single hexagonal grains by resonance-frequency shifts of the oscillator in resonance ultrasound microscopy. 相似文献
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The purpose of this study is to develop a method for measuring elastic constants using a LFB acoustic microscope. For this
purpose, a theoretical procedure for the estimation of Young's modulus and Poisson's ratio is introduced based on elastic
theory. According to this procedure, experimental velocity measurement and elastic constants estimation are made by use of
a LFB acoustic microscope. For the confirmation of the availability of this method, the estimated elastic constant is compared
to measurements of elastic constants by other methods. The resulting estimated values of Young's modulus and Poisson's ratio
obtained by the LFB acoustic microscope are highly accurate which confirms the usefulness of the elastic constant measurement
system.
T. Mihara is Research Associate, and M. Obata (former SEM Member), deceased, was Professor, Department of Materials Processing,
Faculty of Engineering, Tohoku University, Aramaki Aoba, Sendai, 980, Japan. 相似文献
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弹性波与单侧界裂纹相互作用问题的边界元法 总被引:1,自引:0,他引:1
措助边界元法设计了一种迭代修正方法来求解单侧界面裂纹模型与弹性波的相互作用问题,作为对算法的检验,用这种方法我们具体地分析了平面简谐弹性波对一个则界面裂纹的入射,给出了裂纹面的接触形态及应力场。 相似文献
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复合材料弹性常数测定的超声波技术 总被引:1,自引:0,他引:1
本文简要地回顾了利用超声波脉冲技术测定复合材料弹性常数的历史,概述了现状、基本原理与基本方法,并对今后的研究方向提出了看法. 相似文献
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本文简要地回顾了利用超声波脉冲技术测定复合材料弹性常数的历史,概述了现状、基本原理与基本方法,并对今后的研究方向提出了看法. 相似文献
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本文根据多层弹性体系在垂直或水平圆形均布荷载作用下的层间连续的接触条件,推导出表示相邻层积分常数间的递推关系矩阵[T],的显式表达式,给出了多层弹性体系力学分析中积分常数计算的矩阵分析方法及其简洁的计算公式。本文所述方法,原理通俗易懂,编程简单方便,计算快速省时,是一种很容易推广应用的有效方法。实例计算表明,本文所述方法是完全正确的。 相似文献
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The 3D contact problem on the action of a punch elliptic in horizontal projection on a transversally isotropic elastic half-space is considered for the case in which the isotropy planes are perpendicular to the boundary of the half-space. The elliptic contact region is assumed to be given (the punch has sharp edges). The integral equation of the contact problem is obtained. The elastic rigidity of the half-space boundary characterized by the normal displacement under the action of a given lumped force significantly depends on the chosen direction on this boundary. In this connection, the following two cases of location of the ellipse of contact are considered: it can be elongated along the first or the second axis of Cartesian coordinate system on the body boundary. Exact solutions are obtained for a punch with base shaped as an elliptic paraboloid, and these solutions are used to carry out the computations for various versions of the five elastic constants. The structure of the exact solution is found for a punch with polynomial base, and a method for determining the solution is proposed. 相似文献
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The complete orthotropic elastic-stiffness matrix of unidirectional, Borsic-filament-reinforced aluminum composites was experimentally evaluated for three different volume fractions by ultrasonic velocity measurements on thin plates. Longitudinal- and shear-velocity measurements were made in appropriate symmetry directions by direct contact or liquid-immersion techniques. The elastic constants determined by this pulsed through-transmission method were in agreement with micromechanical theories based on the properties of the constituent materials. Agreement was also found between engineering constants determined by mechanical testing and those calculated from the ultrasonic data. Finally, measurement of the ultrasonic-wave velocity has also been shown to be a rapid nondestructive-test method for determining filament-volume fraction in a fabricated part. 相似文献