考虑表面强化或损伤的抗压强度能量平衡尺寸效应模型  

ENERGY BALANCE SIZE EFFECT MODEL CONSIDERING THE SURFACE STRENGTHENING OR DAMAGE FOR COMPRESSIVE STRENGTH

作　　者：刘小宇 张慧梅[1] 杨政[2] 李江博 Liu Xiaoyu;Zhang Huimei;Yang Zheng;Li Jiangbo(College of Sciences,Xi'an University of Science and Technology,Xi'an 710600,China;School of Human Settlement and Civil Engineering,Xi'an Jiaotong University,Xi'an 710049,China)

机构地区：[1]西安科技大学理学院,西安710600 [2]西安交通大学人居环境与建筑工程学院,西安710049

出　　处：《力学学报》2025年第3期671-686,共16页Chinese Journal of Theoretical and Applied Mechanics

基　　金：国家自然科学基金(12172280,12472406);陕西省教育厅专项科研计划(19JK0521)资助项目.

摘　　要：表面强化或损伤与局部损伤区(或称断裂过程区)会导致准脆性材料名义强度呈现尺寸效应,但是建立考虑这两种因素的模型依旧是尺寸效应研究方向挑战性问题之一.首先深入系统分析引发试样表面强化或损伤的因素,提出能够反映试样表面强化或损伤的尺寸效应模型.在此基础上,通过分析试样表面强化或损伤层与内部区域引发的尺寸效应,结合表面强化或损伤尺寸效应模型和笔者之前提出的能量平衡尺寸效应模型,建立考虑表面强化或损伤的能量平衡尺寸效应模型(EBM-SSD).然后对EBM-SSD进行参数分析.最后应用EBM-SSD预测3种类型尺寸效应试验和模拟数据,并和笔者之前提出的考虑局部损伤区变化的能量平衡尺寸效应模型(EBM-LDZ)预测对比.结果表明:EBM-SSD能体现无尺寸效应、上升尺寸效应、下降尺寸效应和先升后降尺寸效应的原因是,随着试样尺寸变化,强化或损伤的表面层与内部区域叠加作用或互相竞争的结果;EBM-SSD能准确描述上升、下降和先升后降3类尺寸效应试验和模拟数据;除编号5 Pilton砂岩,EBMSSD预测剩余试验和模拟尺寸效应数据的确定系数均大于EBM-LDZ,并且其平均确定系数为0.9729.Surface strengthening or damage and localized damage zone(otherwise known as fracture process zone)can cause the size-dependent nominal strength of quasi-brittle materials.However,developing a model that can encompass these two factors remains one of the challenging issues in size effect research.In this paper,a size effect model,which can reflect the surface strengthening or damage of the specimen,is firstly established by systematically and in depth analyzing the factors that induce surface strengthening or damage on the specimen.On this basis,the size effects caused by the specimen's surface layer and the interior zone are analyzed,and then energy balance size effect model considering the surface strengthening or damage(EBM-SSD)is proposed by integrating the size effect model of surface strengthening or damage and the energy balance size effect model previously proposed by the author.Subsequently,a parametric analysis of the EBM-SSD is conducted.Finally,the EBM-SSD is applied to predict experimental and simulated data for three types of size effects and compared with predictions from the energy balance size effect model considering variations in the local damage zone(EBM-LDZ)previously proposed by the author.The results indicate that the ability of the EBM-SSD to capture no,ascending,descending,and ascending-then-descending size effects stems from the superposition or competition between the strengthened or damaged surface layer and the internal region as the specimen size varies.The comparison results show that EBM-SSD can accurately describe the ascending,descending,and initial rise and subsequent decline size effects.Except for sample No.5 Pilton sandstone,the determination coefficients R2 of EBM-SSD for the remaining experimental and simulated size effect data is higher than that of EBMLDZ,and its mean determination coefficient R_(mean)^(2) is 0.9729.

关 键 词：表面强化或损伤效应 能量平衡 抗压强度 尺寸效应模型 

分 类 号：O346[理学—固体力学]