Mathern Alexandre, Yang Jincheng
Department of Architecture and Civil Engineering, Division of Structural Engineering, Concrete Structures, Chalmers University of Technology, SE-412 96 Gothenburg, Sweden.
Research and Innovation, NCC, Lilla Bomen 3c, SE-411 04 Gothenburg, Sweden.
Materials (Basel). 2021 Jan 21;14(3):506. doi: 10.3390/ma14030506.
Nonlinear finite element (FE) analysis of reinforced concrete (RC) structures is characterized by numerous modeling options and input parameters. To accurately model the nonlinear RC behavior involving concrete cracking in tension and crushing in compression, practitioners make different choices regarding the critical modeling issues, e.g., defining the concrete constitutive relations, assigning the bond between the concrete and the steel reinforcement, and solving problems related to convergence difficulties and mesh sensitivities. Thus, it is imperative to review the common modeling choices critically and develop a robust modeling strategy with consistency, reliability, and comparability. This paper proposes a modeling strategy and practical recommendations for the nonlinear FE analysis of RC structures based on parametric studies of critical modeling choices. The proposed modeling strategy aims at providing reliable predictions of flexural responses of RC members with a focus on concrete cracking behavior and crushing failure, which serve as the foundation for more complex modeling cases, e.g., RC beams bonded with fiber reinforced polymer (FRP) laminates. Additionally, herein, the implementation procedure for the proposed modeling strategy is comprehensively described with a focus on the critical modeling issues for RC structures. The proposed strategy is demonstrated through FE analyses of RC beams tested in four-point bending-one RC beam as reference and one beam externally bonded with a carbon-FRP (CFRP) laminate in its soffit. The simulated results agree well with experimental measurements regarding load-deformation relationship, cracking, flexural failure due to concrete crushing, and CFRP debonding initiated by intermediate cracks. The modeling strategy and recommendations presented herein are applicable to the nonlinear FE analysis of RC structures in general.
钢筋混凝土（RC）结构的非线性有限元（FE）分析具有众多建模选项和输入参数。为了准确模拟涉及混凝土受拉开裂和受压破碎的非线性RC行为，从业者在关键建模问题上做出了不同选择，例如定义混凝土本构关系、确定混凝土与钢筋之间的粘结以及解决与收敛困难和网格敏感性相关的问题。因此，必须严格审视常见的建模选择，并制定一种具有一致性、可靠性和可比性的稳健建模策略。本文基于对关键建模选择的参数研究，提出了一种用于RC结构非线性有限元分析的建模策略和实用建议。所提出的建模策略旨在提供对RC构件弯曲响应的可靠预测，重点关注混凝土开裂行为和受压破坏，这为更复杂的建模案例（例如粘贴纤维增强聚合物（FRP）层压板的RC梁）奠定基础。此外，本文全面描述了所提出建模策略的实施过程，重点关注RC结构的关键建模问题。通过对在四点弯曲试验中测试的RC梁进行有限元分析来验证所提出的策略——一根RC梁作为参考，另一根梁在其 soffit 处外部粘贴了碳纤维增强塑料（CFRP）层压板。在荷载-变形关系、开裂、混凝土受压导致的弯曲破坏以及由中间裂缝引发的CFRP脱粘方面，模拟结果与实验测量结果吻合良好。本文提出的建模策略和建议一般适用于RC结构的非线性有限元分析。
