砌体轴心和局部受压离散元仿真在教学中的应用  

Pedagogical application of discrete element simulation to brick masonry in uniaxial and localized compression

作　　者：李涛[1] 蔡靖[1] LI Tao;CAI Jing(School of Transportation Science and Engineering,Civil Aviation University of China,Tianjin 300300,China)

机构地区：[1]中国民航大学交通科学与工程学院,天津300300

出　　处：《实验技术与管理》2024年第3期156-164,共9页Experimental Technology and Management

基　　金：国家自然科学基金项目(52268056);中央高校基本科研业务费专项资助(3122021116)。

摘　　要：砌体是块体和砂浆的黏结组合材料,为了让学生更好地理解砖块体和砂浆对外力的分担作用,运用离散元方法建立了砖块体团簇模型、砂浆团簇模型,进而“砌筑”了普通砖砌体数值试件,对砖砌体分别开展轴心受压和局部受压仿真。仿真复现了砌体受压时的应力-应变关系和破坏模式,应力峰值处伴随大量砖颗粒-砖颗粒胶结接触破坏。砌体应力主要由胶结接触承担,其中砖-砖胶结接触>砖-砂浆胶结接触>砂浆-砂浆胶结接触,砂浆主要起到连接块体的作用;法向接触力承力大于切向接触力。通过仿真教学,有助于学生建立砌体宏观力学表现受控于微观结构和微观力学的认知,加深了学生对砌体受力机理和强度的理解。[Objective]Masonry architecture combines science and art,promoting architectural diversity and culture.The requirement of green and low-carbonization of new town construction provides a new opportunity for developing masonry structures.Masonry structure is an essential professional course in civil engineering education,with the compression of unreinforced masonry being an important part of this course.Masonry is a material that combines brick and mortar.Illustrating masonry failure subjected to compression can help students comprehend the concept of the stress contribution of combined materials,which is vital in the design and reinforcement of masonry structures.[Methods]Discrete element simulation has become an essential supplement to practical teaching and has been increasingly used because of its economy,reproducibility,whole-process illustration,and ability to obtain micromechanical data.To facilitate students’comprehension of the contribution of brick and mortar to bearing external forces,we established brick and mortar clusters and then simulated brick masonry using the discrete element method.Uniaxial and localized compression were conducted on the numerical brick masonry,with the stress–strain relationship,masonry failure mode,bond contact breakage,and the contribution of contact forces to stress analyzed.[Results]The numerical simulation replicates the failure modes of masonry and the corresponding stress–strain relationships under compression.When the masonry is uniaxially and locally compressed,the axial stress reaches its peak value and decreases rapidly,followed by a slow decrease.When the bond strength of the mortar is 30 MPa,under uniaxial compression,the mortar in horizontal and vertical joints is first damaged,subsequent brick–brick bond breakages lead to the splitting of the bricks,and the cracks continue to expand,causing the blocks to break.Thus,many blocks are extruded,and a diagonal shear band appears.In localized compression,failure occurs primarily within a depth range of twice the

关 键 词：砖砌体 轴心受压 局部受压 离散单元法 虚拟仿真 

分 类 号：O346.3[理学—固体力学]