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光弹性涂层法是最常用的实验应变分析测试技术之一,但其实际应用受到诸如准备时间长、基底加强效应、复杂的数据后期处理等固有局限性的影响。近年来,出现了两种通过在光弹性聚合物材料中添加非发光染料或发光染料的新的光弹性涂层制作方法。这种基于染料的光弹性涂层使新方法能够克服上述传统光弹性涂层法应用中的许多局限性,并有望成为重要的应变测量工具。论文回顾了这两种新的基于染料的光弹性涂层方法的提出与发展过程,分别介绍了两种测量方法的实验装置、基本原理及一些实际应用,总结了两种新方法各自的优点与不足。最后指出了基于添加发光染料的发光光弹性涂层的未来发展方向和技术改进。 相似文献
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光弹性法是研究结构内部应力分布问题的一个有效方法.光弹性实验中,通常可以方便地得到等色线条纹图.确定了等色线条纹级数以后,为获得平面模型中任意点的应力完全解,需要借助其它方法给出一个补充方程.本文将光弹性法与数字散斑相关法相结合,提出一种用于光弹性法分离主应力的新方法:光弹性-数字散斑相关混合法.在理论研究的基础上,设计了光弹性-数字散斑相关混合法实验系统,并通过相应的三点弯曲实验对该方法和实验系统的有效性做出分析和论证.该研究为光弹全场应力分解以及动态光弹性-数字散斑相关混合法提供了理论和实验基础. 相似文献
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本文提出的光弹性自动检测分析系统,是通过光电扫描和微型计算机自动条集和处理光弹性条纹信息,能实时,准确、迅速地检测条纹密度变化很大的受力模型,仅在十几分钟内就可输出(显示和打印)全场应力光图条纹中心线及其坐标,而且结构简单,造价低(仅为其他类型的自动光弹性系统的十分之一到二十分之一). 相似文献
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提出了从光弹性数据中分离主应力的一种新方法——综合法。该法简单实用,容易掌握,有足够的精度,不需单独测定材料条纹值,简化了实验步骤。 相似文献
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复合材料光弹性分析的工程方法 总被引:1,自引:0,他引:1
本文在推导均衡光弹性复合材料应力(应变)—光定律的基础上,导出了均衡光弹性复合材料的近似应变—光定律。然后加以推广,提出适用于一般光弹性复合材料的近似应变—光定律.精度分析及实验验证表明:作为工程计算,在采用本文推荐的参数时,光弹性复合材料可视作各向同性材料进行光弹性分析。 相似文献
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本文讨论下面几个问题:三维光弹性基本方程;特征量(包括特征方向及特征位相差)与应力分量之间的关系;光弹性基本方程的解。这些问题都是已解决的问题,本文的目的,一是改进解决方法使之简易直接,再是对于改进方法中所依据的物理概念使之更加明确,这样就使这些复杂问题变得易于接受。 相似文献
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光弹性复合材料对径受压圆板应力分析与材料条纹值测定 总被引:1,自引:0,他引:1
本文根据 Okubo 的各向异性分析,对纤维增强光弹性复合材料制成的对径受纹压圆板进行了研究;在此基础上提出了采用一个对径受压圆板测定光弹性复合材料三个条值(f_L,f_T,f_(LT))的方法。经与由三棵光弹性复合材料直条试样测定的相应材料条纹值数据比较,发现现在提出的方法更为简便、可靠。 相似文献
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本文介绍焦散线-光弹性方法,在一次曝光时,能记录焦散线和光弹性二种信息,具有光路简单,信息丰富等优点,利用实验结果不仅能确定断裂力学中的应力强度因子 K_I,而且进一步能分离裂尖附近的主应力分量,同时讨论了与该方法有关的一些问题。 相似文献
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J. Hubner L. Chen Y. Liu K. Schanze P. Ifju J. Nicolosi W. El-Ratal 《Experimental Mechanics》2005,45(2):137-143
The luminescent photoelastic coating (LPC) technique measures the full-field shear strain and its principal direction on the
surface of complex three-dimensional components. The measured optical strain response is also dependent on the coating thickness.
Achieving uniform coating thickness is difficult, and thus requires thickness correction for accurate quantitative strain
measurements. The original formulations of LPC employed a dual-layer coating containing luminescent dyes to transmit both
strain and thickness information. This paper will document (theory and experiment) a new strategy: a single-layer coating
that incorporates both a luminescent dye and an absorption dye. Dependent on the concentration of the absorption and luminescent
dyes, the solution is sprayed onto the object of interest to a minimum threshold thickness that corresponds to a predefined
penetration depth. Advantages of the single-layer coating are the elimination of thickness dependency, the elimination of
compliance and adhesion issues between multiple layers, simpler data acquisition and post-processing methods, and easier and
faster coating preparation and application. 相似文献
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This paper presents the theoretical modeling and corresponding experimental results of the oblique incidence response of a
luminescent photoelastic coating (LPC) applied to a cylinder under load. LPC is a measurement technique to acquire full-field
maximum shear strain and its principal strain direction. The technique uses an absorption dye and a luminescent dye within
a photoelastic coating, and the coating is applied on the surface of the specimen using conventional aerosol techniques. On
3D objects, the response of the emission field is dependent on the excitation orientation due to the surface inclination of
the structural component and the out-of-plane strain component within the coating. Full-field strain separated results have
been previously demonstrated on a 2D specimen. The extension of the strain separation technique to a 3D specimen—a cylinder
in bending—is the focus of this investigation. Two different responses were obtained from normal and oblique excitation. As
a result, the principal strain was separated over ±56° of circumference of the cylinder with RMS error relative to the theoretical
result of 87 μɛ for maximum principal strain and 78 μɛ for minimum. 相似文献
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This paper presents a theoretical model and corresponding experimental results of the oblique-incidence response of a luminescent
photoelastic coating (LPC). LPCs use a luminescent dye that both partially preserves the stress-modified polarization state
and provides high emission signal strength at oblique surface orientations. These characteristics enable the technique to
acquire full-field strain separated measurements and principal strain directions, potentially on complex three-dimensional
geometries, without the use of supplemental experimental or analytical techniques. Results of a single-layer LPC on a disk
in diametral compression are presented to assess a theoretical model and evaluate the measurement sensitivity.
相似文献
J. P. HubnerEmail: |
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本文介绍了在贴片光弹测试中分离主应力的一种新方法.它是借助于一种电容传感器,通过测定主应变之和从而达到分离主应力的目的. 相似文献
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光弹性贴片法研究钢纤维活性粉末混凝土断裂性能 总被引:2,自引:0,他引:2
采用预制裂缝的三点弯曲试件,应用光弹性贴片法研究了不同纤维掺量活性粉末混凝土RPC200的断裂性能.实验获取了光弹贴片所显示的裂缝扩展全过程,由光弹性条纹分析了不同纤维掺量试件的初裂荷载及临界有效裂缝长度的变化规律.实验表明,利用光弹性贴片法可以有效的获取钢纤维混凝土裂缝扩展的全过程;随着钢纤维掺量的增加,试件的初裂荷载和峰值荷载得到相应提高,且峰值荷载呈近似线性的增加;当纤维掺量为1%时,临界有效裂缝长度值最大;纤维掺量继续增加,其分布均匀性下降,试件的韧性降低,临界有效裂缝长度减少. 相似文献
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For critical load bearing structures, it is often necessary to experimentally determine the load distribution on the structure
so that accurate finite element models can be developed for stress and fatigue life predictions. An inverse problem approach
is presented here for computing or calibrating the loads and boundary conditions acting on a structure. This enables the creation
of more accurate finite element models, especially for structures that have complicated load distribution and compliant boundary
conditions. The method presented here involves minimizing the least square error between the strains computed using the finite
element model and the strains and displacements obtained experimentally. The nodal loads and the compliance at fixed boundaries
are treated as the variables in the optimization problem. The compliance is modeled as springs attached at the nodes that
are on the boundary where the structure is restrained. The method is verified by computing the loads and boundary conditions
when displacements, maximum shear strain or both are available at large number of points on the surface of the structure.
The experimental data set was generated using the luminescent photoelastic coating (LPC) technique. 相似文献