Mitchell Jeffrey P, Cho Bum-Yean, Kim Yoo-Jae
Department of Civil Engineering, Washington University in St. Louis, 1 Brookings Drive, Saint Louis, MO 63130, USA.
Department of Fire Safety Research, Korea Institute of Civil Engineering and Building Technology, 64 Ma-doro, 182 Beon-gil, Mado-myeon, Hwaseong-si, Gyeonggi-do 18544, Korea.
Materials (Basel). 2021 Mar 17;14(6):1460. doi: 10.3390/ma14061460.
There are a multitude of existing material models for the finite element analysis of cracked reinforced concrete that provide reduced shear stiffness but do not limit shear strength. In addition, typical models are not based on the actual physical behavior of shear transfer across cracks by shear friction recognized in the ACI 318 Building Code. A shear-friction model was recently proposed that was able to capture the recognized cracked concrete behavior by limiting shear strength as a yielding function in the reinforcement across the crack. However, the proposed model was formulated only for the specific case of one-directional cracking parallel to the applied shear force. This study proposed and generalized an orthogonal-cracking shear-friction model for finite element use. This was necessary for handling the analysis of complex structures and nonproportional loading cases present in real design and testing situations. This generalized model was formulated as a total strain-based model using the approximation that crack strains are equal to total strains, using the proportional load vector, constant vertical load, and modified Newton-Raphson method to improve the model's overall accuracy.
对于开裂钢筋混凝土的有限元分析，现有大量材料模型，这些模型能提供降低的抗剪刚度，但并不限制抗剪强度。此外，典型模型并非基于美国混凝土学会（ACI）318建筑规范中所认可的通过剪摩擦在裂缝间进行剪力传递的实际物理行为。最近提出了一种剪摩擦模型，该模型能够通过将抗剪强度限制为裂缝处钢筋中的屈服函数来捕捉公认的开裂混凝土行为。然而，所提出的模型仅针对与施加剪力平行的单向开裂的特定情况进行了公式化。本研究提出并推广了一种用于有限元分析的正交开裂剪摩擦模型。这对于处理实际设计和测试情况中存在的复杂结构分析和非比例加载情况是必要的。这个广义模型被公式化为基于总应变的模型，采用裂缝应变等于总应变的近似方法，使用比例荷载向量、恒定竖向荷载以及改进的牛顿 - 拉夫逊方法来提高模型的整体精度。
