金浏, 杜修力. 基于细观单元等效化方法的混凝土动态破坏行为分析[J]. 工程力学, 2015, 32(4): 33-40. DOI: 10.6052/j.issn.1000-4750.2014.03.0219
引用本文: 金浏, 杜修力. 基于细观单元等效化方法的混凝土动态破坏行为分析[J]. 工程力学, 2015, 32(4): 33-40. DOI: 10.6052/j.issn.1000-4750.2014.03.0219
JIN Liu, DU Xiu-li. ANALYSIS OF DYNAMIC FAILURE BEHAVIOR OF CONCRETE BASED ONTHE MESO-ELEMENT EQUIVALENT METHOD[J]. Engineering Mechanics, 2015, 32(4): 33-40. DOI: 10.6052/j.issn.1000-4750.2014.03.0219
Citation: JIN Liu, DU Xiu-li. ANALYSIS OF DYNAMIC FAILURE BEHAVIOR OF CONCRETE BASED ONTHE MESO-ELEMENT EQUIVALENT METHOD[J]. Engineering Mechanics, 2015, 32(4): 33-40. DOI: 10.6052/j.issn.1000-4750.2014.03.0219

基于细观单元等效化方法的混凝土动态破坏行为分析

ANALYSIS OF DYNAMIC FAILURE BEHAVIOR OF CONCRETE BASED ONTHE MESO-ELEMENT EQUIVALENT METHOD

  • 摘要: 混凝土材料具有明显的应变率效应,对其力学性质增强机理的认识还不统一。在细观随机骨料模型基础上,采用特征单元尺度划分试件网格,推导了考虑材料拉/压强度应变率效应的细观单元等效本构关系,建立了非均质混凝土材料的细观单元等效化数值模型。基于二维模型对Dilger等混凝土动态压缩试验进行了数值模拟,获得的数值结果与试验数据及随机骨料模型结果吻合良好,证明了细观单元等效化方法的准确性;进而对三维混凝土试件动态单轴拉伸和压缩破坏模式及宏观力学性质的加载速率效应进行了研究。数值结果表明:随着加载速率的增加,混凝土裂纹(损伤)数量增大,混凝土破坏将耗散更多的能量,是混凝土动态强度提高的主要原因。

     

    Abstract: The dynamic mechanical behavior of concrete has an obvious strain-rate dependency. However, the current knowledge on the enhancement of dynamic mechanical properties of concrete is not well established at present. Based on the random aggregate structure of concrete, the mesh grid was divided by the characteristic element size of concrete. The equivalent constitutive relationship for concrete meso-elements was derived combining the strain-rate effect of material strength, and a three-dimensional meso-element equivalent model of heterogeneous concrete was developed. The dynamic compressive tests conducted by Dilger et al were simulated using a two-dimensional model. Results from the present meso-element equivalent method (MEEM) showed favorable agreement with experimental observations and the results from the random aggregate model, illustrating the accuracy of the present meso-mechanical approach. Under different loading rates, the dynamic failure patterns and the macroscopic mechanical properties of the three-dimensional concrete specimen subjected to uniaxial tension and compression were investigated subsequently. It is found that, as loading rate increases the number of cracks or the damaged region increases, implying that the fracture process at high rates requires more energy demand to reach failure, which is the major reason for the enhancement of concrete dynamic strength.

     

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