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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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该文分析了多媒体教学和板书教学各自的优势,依据工程力学课程的教学特点,结合多媒体和板书教学的优点,探讨了多媒体与板书相结合的课堂教学模式。针对工程力学课堂教学,该文采用单纯多媒体以及多媒体与板书相结合的两种教学模式,进行了对比教学实践。实践结果表明,采用多媒体和板书相结合的教学模式,学生的迟到、早退和旷课现象大大减少,学生对知识的理解和掌握情况很好。该教学模式锻炼了学生的逻辑思维能力,提高了学生的学习兴趣。 相似文献
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分析了网络环境下档案信息安全面临的风险及威胁档案信息安全的因素,并从网络环境营造以及安全技术应用等角度对保障网络环境下档案信息安全的具体措施进行了研究. 相似文献
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An Approach for Calculating Strain Distributions in Arbitrarily Shaped Quantum Dots 总被引:1,自引:0,他引:1 下载免费PDF全文
We study strain distribution inside and outside an arbitrarily-shaped quantum dot (QD) buried in an infinite isotropic medium. By defining a very simple vector, we derive a compact formula for stress fields expressed by an integral over the interface between the QD and its surrounding material. Using this method, the analytical solution for a cuboidal QD is obtained, which is different from the previous result. It is shown that our solution satisfies the traction continuity condition on the interface. Based on this solution, it is found that the strain field in the cuboidal QD in the semiconductor heterostructure is sensitive to its height. In addition, the strain distribution around a hemispherical QD is also calculated and demonstrated. 相似文献
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目前企业产权制度改革正以前所未有的创新精神和效率意识,在全国城乡全面展开。企业改制后如何提高发展水平、赢得更大的发展,这是企业改制的最终目的和根本目标。改制企业只有克服短期行为,切实增强发展后劲,才能冲劲足,后劲足,才能跑得远。 很显然,如果改制企业仍然停留在原有的状况、停留在原有的生产能力、技术水平,停留在原有的管理方式、营销手段,没有新的投入,不作丝毫的创新和提高,而只是换了个“东家”,国有集体资产变为民营、私有,那么,企业经营状况就不可能会有根本性的好转,就不 相似文献
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1引言 国际理论与应用力学大会 (Internationa Con-gress of Theoretical and Applied Mechanics,简称ICTAM)每四年召开一次,素有力学“奥林匹克运动会”之称.第20届 ICTAM于 2000年 8月 27日至9月2日在美国芝加哥市举行.ICTAM历来有着活跃在力学研究最前沿的众多学者出席,交流着大量成果,涉及力学理论与应用的各个方面,基本上反映出力学的整体新进展.鉴于参加本次会议的国内代表只有20多人,应《力学进展》之约,我们共同撰写了这份报… 相似文献
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本文首先介绍了高聚物复合材料界面微观结构的特点和界面破坏的微观形式, 在此基础上,详细回顾了粒子填充高分子复合材料和共混高分子合金两类材料的界面力学性能实验研究的进展,总结了研究粒子/基体界面力学性能的实验方法和用这些方法获得的实验结果。介绍的实验方法从宏观拉伸实验到细观在位拉伸实验, 从定性的断口形貌分析到定量的界面强度和粘结能计算, 从不同层次和角度阐述了研究界面性能各种方法的优缺点。最后, 作者根据综合分析的结果, 指出了实验研究界面力学性能遇到的主要困难来自实验仪器的局限性和实验方法的匮乏性。为了获得可靠的界面性能, 一方面应该设计出利于表征的界面, 另一方面需要在实验技术上有所创新。相信该文对于深入了解和研究共混/填充高分子复合材料的界面问题, 以及其它类型材料的界面问题具有一定的借鉴意义。 相似文献
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