Establishment and finite element mesh of 3D mesoscopic stochastic models of concrete
-
摘要: 将混凝土假定为由骨料和砂浆组成的两相复合材料, 研究了球形、椭球形和两者混合体的边界和干涉判断数学条件; 设计了球形、椭球形骨料随机投放算法, 并利用MATLAB编制相应程序, 生成了混凝土细观层次三维随机几何模型; 采用相邻骨料颗粒中心距判断球形骨料的干涉关系, 利用一个椭球上任一点与另一个椭球形心连线构成的直线段上的任一点与该椭球的关系判断椭球形骨料的干涉关系, 将两椭球之间的干涉关系转化为一点与椭球的关系; 基于MATLAB平台开发了mat2scr2017程序, 将MATLAB中的图形文件数据读入SCR脚本文件中, 将mat2scr 2017程序生成的随机骨料模型转化为AutoCAD图形文件, 并导入有限元软件COMSOL Multiphysics中剖分混凝土几何模型有限元网格。研究结果表明: 建立的随机骨料模型的骨料体积率可达到50%, 骨料粒径和投放位置均满足随机性要求; 椭球形随机骨料投放算法简单、高效, 且能保证椭球自身倾角的随机性; 模型适用于任意级配混凝土的生成, 对连续级配混凝土骨料的逐级随机投放保证了各级配骨料的体积率; 实现了MATLAB图形向AutoCAD图形的转换, 极大地提高了混凝土随机骨料模型的通用性; 所建混凝土模型网格剖分满足骨料、砂浆交界处网格一致性要求, 满足有限元分析的需要。Abstract: The concrete was assumed to be a two-phase composite material of aggregate and mortar.The mathematical boundary conditions and interference judgment of spherical and ellipsoid aggregates and their mixtures were studied, respectively.A stochastic packing algorithm was designed for the spherical and ellipsoid aggregate, and a corresponding program was compiled using MATLAB to realize the generation of a three-dimensional mesoscopic stochastic geometric model of concrete.The interference relationship of spherical aggregates was judged by the center distance between adjacent aggregate particles.The interference between ellipsoidal aggregates was judged by the relationship between any point on an ellipsoid and a point on the straight-line segment formed by the connection of any point on an ellipsoid and the center of another ellipsoid.Thus, the interference relationship between two ellipsoids was simplified as the relationshipbetween an ellipsoid and a point.A program named mat2 scr 2017 was developed on MATLAB to read the graphic file data from MATLAB into SCR script file.The stochastic aggregate model built with mat2 scr 2017 program was transformed into an AutoCAD graphics file and input into the COMSOL Multiphysics software.The finite element mesh of concrete geometric model was carried out through COMSOL Multiphysics.Research result shows that the volume ratio of the stochastic aggregate model can reach 50%, and the aggregate size and packed position meet the randomness requirements.The ellipsoid random aggregate packing algorithm is simple and efficient, and can guarantee the randomness of dip angle of ellipsoid.The model is applicable to the generation of arbitrarily graded concrete, and the continuously graded concrete aggregates are packed according to different gradations, thus ensuring the volume ratio of the aggregates at all levels.The conversion of MATLAB graphics to AutoCAD graphics is realized, and the generality of stochastic concrete model is greatly enhanced.The mesh generation of the concrete model meets the requirement of grid consistency at the interface of aggregate and mortar, and the needs for finite element analysis.
-
Key words:
- bridge engineering /
- concrete /
- stochastic aggregate /
- packing algorithm /
- MATLAB /
- mesh generation
-
表 1 粗骨料级配
Table 1. Coarse aggregate gradation
-
[1] WANG L C, UEDA T. Mesoscale modeling of water penetration into concrete by capillary absorption[J]. Ocean Engineering, 2011, 38 (4): 519-528. doi: 10.1016/j.oceaneng.2010.12.019 [2] 陈艾荣, 潘子超, 马如进, 等. 基于细观尺度的桥梁混凝土结构耐久性研究新进展[J]. 中国公路学报, 2016, 29 (11): 44-48. https://www.cnki.com.cn/Article/CJFDTOTAL-ZGGL201611008.htmCHEN Ai-rong, PAN Zi-chao, MA Ru-jin, et al. New development of mesoscopic research on durability performance of structural concrete in bridges[J]. China Journal of Highway and Transport, 2016, 29 (11): 44-48. (in Chinese). https://www.cnki.com.cn/Article/CJFDTOTAL-ZGGL201611008.htm [3] GRASSL P, PEARCE C. Mesoscale approach to modeling concrete subjected to thermomechanical loading[J]. Journal of Engineering Mechanics, 2010, 136 (3): 322-328. doi: 10.1061/(ASCE)0733-9399(2010)136:3(322) [4] RUAN Xin, PAN Zi-chao. Mesoscopic simulation method of concrete carbonation process[J]. Structure and Infrastructure Engineering, 2012, 8 (2): 99-110. doi: 10.1080/15732479.2011.605370 [5] 金浏, 杜修力. 加载速率对混凝土拉伸破坏行为影响的细观数值分析[J]. 工程力学, 2015, 32 (8): 42-49. https://www.cnki.com.cn/Article/CJFDTOTAL-GCLX201508008.htmJIN Liu, DU Xiu-li. Meso-scale numerical analysis of the effect of loading rate on the tensile failure behavior of concrete[J]. Engineering Mechanics, 2015, 32 (8): 42-49. (in Chinese). https://www.cnki.com.cn/Article/CJFDTOTAL-GCLX201508008.htm [6] 胡大琳, 陈定市, 张立兴, 等. 饱水混凝土氯离子侵蚀数值试验随机细观分析[J]. 长安大学学报: 自然科学版, 2017, 37 (6): 38-46. doi: 10.3969/j.issn.1671-8879.2017.06.006HU Da-lin, CHEN Ding-shi, ZHANG Li-xing, et al. Mesoscopic and stochastic analysis of chloride on erosion in saturated concrete by numerical tests[J]. Journal of Chang'an University: Nature Science Edition, 2017, 37 (6): 38-46. (in Chinese). doi: 10.3969/j.issn.1671-8879.2017.06.006 [7] 陈定市. 混凝土多因素侵蚀耦合随机细观研究[D]. 西安: 长安大学, 2016.CHEN Ding-shi. Mesoscopic and stochastic study on multifactor coupled concrete erosion[D]. Xi'an: Chang'an University, 2016. (in Chinese). [8] WITTMANN F H, ROELFSTRA P E, SADOUKI H. Simulation and analysis of composite structures[J]. Materials Science and Engineering, 1985, 68 (2): 239-248. doi: 10.1016/0025-5416(85)90413-6 [9] 王宗敏, 邱志章. 混凝土细观随机骨料结构与有限元网格剖分[J]. 计算力学学报, 2005, 22 (6): 728-732. doi: 10.3969/j.issn.1007-4708.2005.06.017WANG Zong-min, QIU Zhi-zhang. Random aggregate structure of mesoscopic concrete and finite element mesh[J]. Chinese Journal of Computational Mechanics, 2005, 22 (6): 728-732. (in Chinese). doi: 10.3969/j.issn.1007-4708.2005.06.017 [10] 高政国, 刘光廷. 二维混凝土随机骨料模型研究[J]. 清华大学学报: 自然科学版, 2003, 43 (5): 710-714. doi: 10.3321/j.issn:1000-0054.2003.05.036GAO Zheng-guo, LIU Guang-ting. Two-dimensional random aggregate structure for concrete[J]. Journal of Tsinghua University: Science and Technology, 2003, 43 (5): 710-714. (in Chinese). doi: 10.3321/j.issn:1000-0054.2003.05.036 [11] 武亮, 王菁, 糜凯华, 等. 全级配混凝土二维细观模型的自动生成[J]. 建筑材料学报, 2015, 18 (4): 626-632. doi: 10.3969/j.issn.1007-9629.2015.04.016WU Liang, WANG Jing, MEI Kai-hua, et al. Automatic generation of 2Dmesoscale models for fully-graded concrete[J]. Journal of Building Materials, 2015, 18 (4): 626-632. (in Chinese). doi: 10.3969/j.issn.1007-9629.2015.04.016 [12] 胡大琳, 张立兴, 陈定市. 二维细观随机混凝土模型的建立的应用[J]. 长安大学学报: 自然科学版, 2017, 37 (3): 53-63. doi: 10.3969/j.issn.1671-8879.2017.03.008HU Da-lin, ZHANG Li-xing, CHEN Ding-shi. Establishment and application of 2D mesoscopic stochastic concrete model[J]. Journal of Chang'an University: Natural Science Edition, 2017, 37 (3): 53-63. (in Chinese). doi: 10.3969/j.issn.1671-8879.2017.03.008 [13] 李运成, 马怀发, 陈厚群, 等. 混凝土随机凸多面体骨料模型生成及细观有限元剖分[J]. 水利学报, 2006, 37 (5): 588-592. doi: 10.3321/j.issn:0559-9350.2006.05.012LI Yun-cheng, MA Huai-fa, CHEN Hou-qun, et al. Approach to generation of random convex polyhedral aggregate model and plotting for concrete meso-mechanics[J]. Journal of Hydraulic Engineering, 2006, 37 (5): 588-592. (in Chinese). doi: 10.3321/j.issn:0559-9350.2006.05.012 [14] LEITE J P B, SLOWIK V, MIHASHI H. Computer simulation of fracture processes of concrete using mesolevel models of lattice structures[J]. Cement and Concrete Research, 2004, 34 (6): 1025-1033. doi: 10.1016/j.cemconres.2003.11.011 [15] HÄFNER S, ECKARDT S, LUTHER T, et al. Mesoscale modeling of concrete: geometry and numerics[J]. Computers and Structures, 2006, 84 (7): 450-461. doi: 10.1016/j.compstruc.2005.10.003 [16] GARBOCZI E J, BULLARD J W. 3Danalytical mathematical models of random star-shape particles via a combination of X-ray computed microtomography and spherical harmonic analysis[J]. Advanced Powder Technology, 2016, 28 (2): 325-339. [17] DU Cheng-bin, SUN Li-guo, JIANG Shou-yan, et al. Numerical simulation of aggregate shapes of two-dimensional concrete and its applications[J]. Journal of Aerospace Engineering, 2013, 26 (3): 515-527. doi: 10.1061/(ASCE)AS.1943-5525.0000181 [18] 窦晓静. 混凝土碳化深度预测的细观随机模型[D]. 上海: 同济大学, 2009.DOU Xiao-jing. Mesoscopic stochastic model of concrete carbonation depth prediction[D]. Shanghai: Tongji University, 2009. (in Chinese). [19] 梁建, 娄宗科, 韩建宏. 基于AUTOCAD的混凝土骨料建模分析[J]. 水利学报, 2011, 42 (11): 1379-1383. https://www.cnki.com.cn/Article/CJFDTOTAL-SLXB201111021.htmLIANG Jian, LOU Zong-ke, HAN Jian-hong. Modelling analysis of the concrete based on AUTOCAD[J]. Journal of Hydraulic Engineering, 2011, 42 (11): 1379-1383. (in Chinese). https://www.cnki.com.cn/Article/CJFDTOTAL-SLXB201111021.htm [20] 程书怀, 任志刚, 李培鹏, 等. 基于LS-DYNA的混凝土三维随机凹凸型骨料数值建模[J]. 武汉理工大学学报, 2014, 36 (12): 89-94, 121. https://www.cnki.com.cn/Article/CJFDTOTAL-WHGY201412018.htmCHENG Shu-huai, REN Zhi-gang, LI Pei-peng, et al. Numerical simulation of concrete aggregates with arbitrary shapes based on ANSYS/LS-DYNA[J]. Journal of Wuhan University of Technology, 2014, 36 (12): 89-94, 121. (in Chinese). https://www.cnki.com.cn/Article/CJFDTOTAL-WHGY201412018.htm [21] 伍君勇. 混凝土细观结构的自动生成[D]. 大连: 大连理工大学, 2006.WU Jun-yong. Automatic generation of mesostructure of concrete[D]. Dalian: Dalian University of Technology, 2006. (in Chinese). [22] 程伟峰. 混凝土架构模型的数值模拟研究[D]. 大连: 大连理工大学, 2008.CHENG Wei-feng. Research on concrete frame and structure by numerical simulation[D]. Dalian: Dalian University of Technology, 2008. (in Chinese). [23] 高利甲, 刘锡军, 王玉梅. 基于MATLAB-混凝土二维细观结构数值模拟骨料随机投放[J]. 湖南工程学院学报: 自然科学版, 2011, 21 (1): 81-84. doi: 10.3969/j.issn.1671-119X.2011.01.024GAO Li-jia, LIU Xi-jun, WANG Yu-mei. Numerical simulation for random embarking of aggregate with twodimensional meso-structure of concrete based on MATLAB[J]. Journal of Hunan Institute of Engineering: Natural Science Edition, 2011, 21 (1): 81-84. (in Chinese). doi: 10.3969/j.issn.1671-119X.2011.01.024 [24] BAZANT Z P, TABBARA M R, KAZEMI M T, et al. Random particle model for fracture of aggregate or fiber composites[J]. Journal of Engineering Mechanics, 1990, 116 (8): 1686-1705. doi: 10.1061/(ASCE)0733-9399(1990)116:8(1686) [25] DE SCHUTTER G, TAERWE L. Random particle model for concrete based on delaunay triangulation[J]. Materials and Structures, 1993, 26 (2): 67-73. doi: 10.1007/BF02472853 [26] WANG Z M, KWAN A K H, CHAN H C. Mesoscopic study of concreteⅠ: generation of random aggregate structure and finite element mesh[J]. Computers and Structures, 1999, 70 (5): 533-544. doi: 10.1016/S0045-7949(98)00177-1 [27] 邱志章. 混凝土细观力学分析与实验模拟[D]. 郑州: 郑州大学, 2004.QIU Zhi-zhang. Meso mechanics analysis and experimental simulation of concrete[D]. Zhengzhou: Zhengzhou University, 2004. (in Chinese). [28] JTG/T F50—2011, 公路桥涵施工技术规范[S].JTG/T F50—2011, technical specification for construction of highway bridge and culverts[S]. (in Chinese). [29] WANG W P, WANG J Y, KIM M S. An algebraic conditionfor the separation of two ellipsoids[J]. Computer AidedGeometric Design, 2001, 18(6): 531-539. (in Chinese) [30] 关振群, 高巧红, 顾元宪, 等. 复合材料细观结构三维有限元网格模型的建立[J]. 工程力学, 2005, 22 (增): 67-72. https://www.cnki.com.cn/Article/CJFDTOTAL-GCLX2005S1011.htmGUAN Zhen-qun, GAO Qiao-hong, GU Yuan-xian, et al. The construction of three-dimensional finite element mesh for microstructure of multiphase composites[J]. Engineering Mechanics, 2005, 22 (S): 67-72. (in Chinese). https://www.cnki.com.cn/Article/CJFDTOTAL-GCLX2005S1011.htm [31] 张海宁, 车向前. 基于AutoCAD的复杂曲线绘制的实现[J]. 煤矿机械, 2003 (1): 48-49. https://www.cnki.com.cn/Article/CJFDTOTAL-MKJX200301025.htmZHANG Hai-ning, CHE Xiang-qian. The realization of drawing the complicated curves based on AutoCAD[J]. Coal Mine Machinery, 2003 (1): 48-49. (in Chinese). https://www.cnki.com.cn/Article/CJFDTOTAL-MKJX200301025.htm [32] 贺云花. AutoCAD与MATLAB结合方法的研究及应用[J]. 煤矿机械, 2008, 29 (9): 190-192. doi: 10.3969/j.issn.1003-0794.2008.09.086HE Yun-hua. Research and application of methods to combine AutoCAD with MATLAB[J]. Coal Mine Machinery, 2008, 29 (9): 190-192. (in Chinese). doi: 10.3969/j.issn.1003-0794.2008.09.086 [33] 王宝庭, 宋玉普, 赵国藩. 混凝土随机颗粒模型的网格自动剖分方法[J]. 大连理工大学学报, 1999, 39 (3): 445-450. https://www.cnki.com.cn/Article/CJFDTOTAL-DLLG903.020.htmWANGBao-ting, SONGYu-pu, ZHAOGuo-fan. Automatically dividing way of mesh for random particle model of concrete[J]. Journal of Dalian University of Technology, 1999, 39 (3): 445-450. (in Chinese). https://www.cnki.com.cn/Article/CJFDTOTAL-DLLG903.020.htm [34] 夏晓舟. 混凝土细观数值仿真及宏细观力学研究[D]. 南京: 河海大学, 2007.XIA Xiao-zhou. The meso numerical simulation and the macro-meso mechanics research for concrete material[D]. Nanjing: Hohai University, 2007. (in Chinese). [35] 高巧红, 关振群, 顾元宪, 等. 混凝土骨料有限元模型自动生成方法[J]. 大连理工大学学报, 2006, 46 (5): 641-646. doi: 10.3321/j.issn:1000-8608.2006.05.004GAO Qiao-hong, GUAN Zhen-qun, GU Yuan-xian, et al. Automatic generation of finite element model for concrete aggregate[J]. Journal of Dalian University of Technology, 2006, 46 (5): 641-646. (in Chinese. doi: 10.3321/j.issn:1000-8608.2006.05.004