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Toughness and characterization of reactive powder concrete with ultra-high strength

Science China(Technological Sciences) 2009年第4期52卷 1000-1018页

作者： Yang Ju HongBin Liu Jian Chen YuDan Jia peihuo peng State Key Laboratory of Coal Resources and Safe Mining China University of Mining & Technology Beijing 100083 China Department of Mechanical & Manufacturing Engineering The University of Calgary 2500 University Drive NW Calgary AB T2N 1N4 Canada The University of Illinois at Urbana-Champaign 1110 West Green Street Urbana IL 61801 USA Building Design Division China Nuclear Power Engineering Co. Ltd Beijing 100840 China School of Civil Engineering University of Nottingham University Park Nottingham NG7 2RD UK

A number of three-point bending and fracture tests of 200 MPa-level reactive powder concrete (RPC) with the various fiber contents have been conducted to probe the nature and characteristics of toughness of RPC200. The contribution of the embedded fibers to improving the crack-resistant capacity, energy absorption capacity and toughness with various deformation mechanisms has been analyzed. Taking account of that the first-crack deformation, peak-load deformation and their improvement varied with the fiber contents and that the deformation mechanism affected differently the performance at the first crack and the peak load, we took the peak-load deformation of plain RPC200 as the reference deformation to measure the toughness of fibered RPC200. Two toughness indices T 2(n−1)(n) and FT 2(n−1)(n) have been formulated based on P-δ responses and P-CMOD responses. The indices quantify the toughness of RPC200 with the various deformation mechanisms relative to perfectly elastoplastic materials by setting the toughness level 2(n−1) as the initial reference. It is shown that the toughness index T 2(n−1)(n) reflects the function of fibers to improve the toughness of RPC with the deformation throughout specimens, but overestimates the contribution to enhancing the toughness in post-peak periods. It underestimates, on other hands, the contribution to improving the toughness in the period from the first crack to the peak load. In contrast, the toughness index FT 2(n−1)(n) properly presents the capability that fibers absorb energy and constrain crack propagation in the matrix when the deformation is concentrated on the open crack. The proposed index unveils the contribution of fibers to toughening RPC200 both in the period from the first-crack to the peak load and in the period of post peak. This characterization method not only reveals the nature of toughness but also levels the toughness of RPC200. I

关键词： reactive powder concrete toughness characterization index deformation mechanism flexure fracture

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黏弹性模型微分型本构方程的矩阵形式

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力学与实践 2022年第2期44卷 358-367页

作者：彭培火黄朝军北京建筑大学理学院北京102612 中国建筑第二工程局有限公司北京100160

针对多个弹性元件和黏性元件以任意连接方式组成的线性黏弹性模型,本文探究了其本构方程的通用矩阵形式表述。首先将研究问题扩展为由Maxwell基本单元构成的标准模型,然后转化为有向图,根据独立路径和闭包围的形式表征出基本应力方程和... 详细信息

针对多个弹性元件和黏性元件以任意连接方式组成的线性黏弹性模型,本文探究了其本构方程的通用矩阵形式表述。首先将研究问题扩展为由Maxwell基本单元构成的标准模型,然后转化为有向图,根据独立路径和闭包围的形式表征出基本应力方程和应变方程,进一步推导得到了任意线性黏弹性模型的微分型本构方程的一般矩阵形式。论文最后总结并建立了一套适合计算机编程的固定范式,利用Python编程实现了该算法、获得了一些数值计算结果。

关键词：黏弹性数学模型微分形式本构方程矩阵形式

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