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This paper presents the applications of digital image correlation technique to the mesoscopic damage and fracture study of
some granular based composite materials including steelfiber reinforced concrete, sandstone and crystal-polymer composite.
The deformation fields of the composite materials resulted from stress localization were obtained by the correlation computation
of the surface images with loading steps and thus the related damage prediction and fracture parameters were evaluated. The
correlation searching could be performed either directly based on the gray levels of the digital images or from the wavelet
transform (WT) coefficients of the transform spectrum. The latter was developed by the authors and showed higher resolution
and sensitivity to the singularity detection. Because the displacement components came from the rough surfaces of the composite
materials without any coats of gratings or fringes of optical interferometry, both surface profiles and the deformation fields
of the composites were visualized which was helpful to compare each other to analyze the damage of those heterogeneous materials.
The project supported by the National Natural Science Foundation of China (10125211 and 10072002), the Scientific Committee
of Yunnan Province for the Program of Steel Fiber Reinforced Concrete, and the Institute of Chemical Materials, CAEP at Mianyang 相似文献
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Characterization of Wave Dispersion in Viscoelastic Cellular Assemblies by Doublet Mechanics 下载免费PDF全文
Using the Voigt model, we analyze wave propagation in viscoelastic granular media with a monatomic lattice, planar simple cubic package and cubical-tetrahedral assembly within the context of doublet mechanics. Microstrains of elongation between the doublet particles are considered in the models. Wave dispersive relations are derived from dynamic equations of the particles involved in the media, and phase velocities and attenuations of the dispersive waves are obtained for the different assemblies. Variations in these dispersion characteristics are analyzed with the changes of cell interval, modulus, and wave frequency. The relations between micro-constants and macro-parameters are presented under the condition of non-scale continuity of the media. 相似文献
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In this paper, we present the applications of Boundary Element Method (BEM) to simulate the electro-mechanical coupling responses
of Micro-Electro-Mechanical systems (MEMS). The algorithm is programmed in our research group based on BEM modeling for electrostatics
and elastostatics. Good agreement is shown while the simulation results of the pull-in voltages are compared with the theoretical/experimental
ones for some examples.
The project supported by the 973 Program (G199033108) and the national Natural Science Foundation of China (10125211) 相似文献
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含偏置裂纹三点弯曲梁的动态断裂行为研究 总被引:15,自引:0,他引:15
采用动态焦散线方法,对含偏置裂纹三点弯曲梁承受横向冲击的弯曲断裂行为进行了一系列动态断裂力学实验研究,分析了无量纲量a/l的改变(a——初始裂纹偏离梁中心线的距离;l——梁长度的一半)对于裂纹动态扩展行为(裂纹起始状态、裂纹尖端的复合应力强度因子、裂纹扩展速度、裂纹扩展轨迹)的影响,并借助动态光弹性应力分析,对应力波与扩展裂纹的相互作用以及应力波传播规律进行探讨.给出了裂纹尖端复合应力强度因子、裂纹扩展速度的变化、裂纹曲裂轨迹以及方向与梁中应力波传播的相互关系 相似文献
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细胞与胞外基质微环境的物理力学相互作用涉及许多复杂的生物信号转导通路,对于细胞的增殖、分化、收缩、迁移和凋亡等都起着重要的调控作用。在单细胞水平上,运用细胞牵引力显微镜方法定量研究细胞活动规律及特点具有重要的生理病理学意义。牵引力显微镜方法的核心在于如何通过基底变形信息反演得到细胞牵引力场。本文首先介绍细胞牵引力反演方法的基本原理,然后针对细胞牵引力求解过程中所涉及到的反问题的病态本性,重点介绍近十几年来细胞牵引力反演算法的研究进展(包括边界元反演算法、基于集中力假设的反演算法、基于积分Boussinesq解的反演算法、基于傅立叶变换的反演算法、基于最优滤波的反演算法等)。 相似文献
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