The Geo-DSCM System and Its Application to the Deformation Measurement of Rock Materials

Digital Speckle Correlation Method (DSCM) is a useful tool for whole field deformation measurement, and has been applied to analyze the deformation field of rock materials in recent years. In this paper, a Geo-DSCM system is designed and used to analyse the more complicated problems of rock mechanics, such as damage evolution and failure procedure. A weighted correlation equation is proposed to improve the accuracy of displacement measurement on a heterogeneous deformation field. In addition, a data acquisition system is described that can synchronize with the test machine and can capture speckle image at various speeds during experiment. For verification of the Geo-DSCM system, the failure procedure of a borehole rock structure is inspected and the evolution of the deformation localization is analysed. It is shown that the deformation localization generally initializes at the vulnerable area of the rock structure but may develop in a very complicated way.

Determination of plastic properties by instrumented spherical indentation: Expanding cavity model and similarity solution approach

The present paper aims to develop a robust spherical indentation-based method to extract material plastic properties. For this purpose, a new consideration of-piling-up effect is incorporated into the expanding cavity model; an extensive numerical study on the similarity Solution has also been performed. As a consequence, two semi-theoretical relations between the indentation response and material plastic properties are derived, with which plastic properties of materials can be identified from a single instrumented spherical indentation curve, the advantage being that this approach no longer needs estimations of contact radius with given elastic modulus. Moreover, the inconvenience in using multiple indenters with different tip angles can be avoided. Comprehensive sensitivity analyses show that the present algorithm is reliable. Also, by experimental verification performed oil three typical materials, good agreement of the material properties between those obtained from the reverse algorithm and experimental data is obtained.

固体力学进展及应用: 庆贺李敏华院士90华诞文集

《固体力学进展及应用：庆贺李敏华院士90华诞文集》收录了近代固体力学基础理论及其应用领域的重要科技成果和最新进展。作者是在同体力学领域工作多年的资深研究员，他们来自各行各业，有丰富的科研与丁作经验。他们提供的论文在相当程度上反映当前同体力学的发展现状与成就，并能看出发展趋势，对未来研究的课题选择有参考价值。《固体力学进展及应用：庆贺李敏华院士90华诞文集》还收集了李敏华院士的珍贵照片和纪念李敏华院士90华诞的庆贺和回忆文章，具有重要的史料价值。

陶瓷晶须增强铝基复合材料初始段性能预测

本文利用挤铸造方法结合热压的方法制备了Al_(18)B_4O_(33)w/Al和SiCw/Al复合材料，实现了对增强体取向的调整。利用SEM在位观测、MTS宏观拉伸等实验方法研究了复合材料的细观结构、细观损伤演化规律和材料的宏观性能。通过理论分析、数值计算，结合实验的方法，定量地讨论了材料性能和其微观结构参数之间的关系，定性地总结了短纤维增强金属基复合材料的细观损伤演化规律。经过分析和实验，阐明了热挤压对短纤维增强金属基复合材料增强体空间取向性（取向密度）的影响；讨论了在短纤维增强金属基复合材料中宏观应变和基体、增强体应变的关系；并且进一步研究了密排、多取向群体短纤维增强体的应变，在材料处于弹性和塑性阶段的演化规律；提出了利用增强体轴向应变和材料宏观应变在该方向的分量之比值λ_f来描述增强体增强效果，给出了λ_f在材料承载过程中的演化规律；总结了短纤维增强金属基复合材料的性能（弹性模量）和晶须空间取向之间的关系；利用修正了的混合定律比较好地预测了短纤维增强金属基复合材料的弹性模量；并且进一步预测了短纤维增强金属基复合材料的弹塑性性能。