A Smeared Crack Modelling Approach for Aggregate Interlock and Mixed Mode Fracture of Concrete
A Smeared Crack Modelling Approach for Aggregate Interlock and Mixed Mode Fracture of Concrete
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DOI：
10.23967/wccm-eccomas.2020.042
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发表时间：
2021-03
期刊：
影响因子：
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通讯作者：
J. Ungermann;V. Adam;J. Hegger;M. Classen
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文献类型：
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作者：
J. Ungermann;V. Adam;J. Hegger;M. Classen
。此贡献的目的是对素混凝土中很少研究的混合模式断裂现象进行数值描述。由于混凝土中的裂缝通常会受到法向位移和剪切位移的影响，因此提出了一种称为虚拟粗糙裂缝模型（FRCM）的新材料模型，它将 I 型虚拟裂缝模型与骨料互锁模型相结合。为了对混合模式行为进行建模，混合模式行为是沿着混凝土裂缝共存的粘性混凝土行为和集料互锁应力的结果，模式 I 行为被认为是对裂纹尖端裂纹形成的主要影响，而模式 II 行为（集料互锁）被假设在沿着裂缝表面引起平移（滑移）时发生。这些拉伸软化和剪切传递定律的组合以及裂纹中两种机制产生的剪切应力和法向应力表征了该模型的主要思想。解决了众所周知的实验基准问题，既可以验证所提出的模型，也可以与商业有限元软件的著名具体模型进行比较。分析表明，FRCM 可以模拟结构响应中从 I 型断裂到混合模式断裂的转变，而与商业数值方法的比较表明商业有限元软件中缺乏对骨料互锁和混合模式行为的适当考虑。
. The intention of this contribution is the numerical description of the rarely investigated phenomenon of mixed mode fracture in plain concrete. Since cracks in concrete are typically subjected to both normal and shear displacements, a new material model called fictitious rough crack model (FRCM) is proposed which combines mode I fictitious crack models with aggregate interlock models. For modelling the mixed mode behavior as the result of coexisting cohesive concrete behavior and aggregate interlock stresses along concrete cracks, mode I behavior is considered as the main influence on crack formation at the crack tip and mode II behavior (aggregate interlock) is assumed to occur when translations are induced along the crack surfaces (slip). The combination of these tension-softening and shear-transfer laws and the resulting shear and normal stresses of both mechanisms in the crack characterizes the main idea of the model. Well-known experimental benchmark problems are solved both for validation of the proposed model as well as for comparison with renowned concrete models of commercial FE software. The analysis shows that the FRCM can simulate the transition from mode I fracture to mixed mode fracture in the structural response while the comparison with commercial numerical approaches demonstrates the lack of appropriate consideration of aggregate interlock and mixed mode behavior in commercial FE software.