混凝土二维干缩开裂分析的改进弥散裂纹模型
TWO DIMENSIONAL ANALYSIS OF DRYING SHRINKAGE MICRO-CRACKING IN CONCRETE WITH MODIFIED SMEARED CRACKING MODEL
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摘要: 现有弥散裂纹模型在模拟混凝土细观干缩开裂时,存在收敛性差、易出现裂纹“误判”的局限。针对此不足,该文提出了等效断裂能开裂破坏准则,用以改进弥散裂纹模型;并应用允许材料破坏的有限元显式解法,模拟了单骨料、随机骨料结构混凝土试件的二维干缩开裂,所得裂纹分布与对比试验观察结果基本吻合,显示了改进弥散裂纹模型在混凝土干缩开裂模拟中的适用性。Abstract: The traditional fracture energy cracking criterion in a smeared cracking model, with the limitation of poor convergence and misjudgement of micro-cracks, is not applicable in the meso-level simulation of drying shrinkage micro-cracking in concrete. A modified smeared cracking model with an equivalent fracture energy cracking criterion is proposed and employed in the simulation of drying shrinkage micro-cracking in concrete specimens using an explicit method available in the commercial software ABAQUS. The micro-crack patterns from simulations of single-aggregate and random-aggregate-structure specimens agree well with the experimental results, showing the applicability of the modified smeared cracking model in modeling the meso-level drying shrinkage micro-cracking in concrete.