<p>The simulation of complex cracking patterns in reinforced concrete (RC) is a challenging task due to the difficulties induced by the interaction and intersections among cracks. To address this issue, a computational framework is developed that is capable of capturing anisotropic fractures in RC. Starting with the extended gradient damage (EGD) model, the stability during the propagation of multi-cracks is upgraded with the proper definition of the dissipating force term in addition to the free energy term. The implicit correspondence between the damage evolution and the cohesive law holds without the damage unloading issue, which is a potential trigger of instability. The decomposition of the free energy term with appropriate consideration of the mixed-mode fracture is proposed to form an enhanced version of EGD for capturing the salient features of anisotropic fractures. Furthermore, the explicit version of the numerical algorithm is developed with the introduction of an auxiliary time-dependent term in the governing equation of the EGD. The proposed computational framework is validated by a number of challenging numerical examples. Not only the load–displacement curves but also the fishnet-like crackings on the RC shear wall are well reproduced.</p>

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A computational framework for anisotropic fractures of RC based on extended gradient damage model

  • Liang Xue,
  • Xiaodan Ren,
  • Lu Hai

摘要

The simulation of complex cracking patterns in reinforced concrete (RC) is a challenging task due to the difficulties induced by the interaction and intersections among cracks. To address this issue, a computational framework is developed that is capable of capturing anisotropic fractures in RC. Starting with the extended gradient damage (EGD) model, the stability during the propagation of multi-cracks is upgraded with the proper definition of the dissipating force term in addition to the free energy term. The implicit correspondence between the damage evolution and the cohesive law holds without the damage unloading issue, which is a potential trigger of instability. The decomposition of the free energy term with appropriate consideration of the mixed-mode fracture is proposed to form an enhanced version of EGD for capturing the salient features of anisotropic fractures. Furthermore, the explicit version of the numerical algorithm is developed with the introduction of an auxiliary time-dependent term in the governing equation of the EGD. The proposed computational framework is validated by a number of challenging numerical examples. Not only the load–displacement curves but also the fishnet-like crackings on the RC shear wall are well reproduced.