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Computers and Concrete
  Volume 24, Number 6, December 2019 , pages 527-539
DOI: https://doi.org/10.12989/cac.2019.24.6.527
 


Analysis of notch depth and loading rate effects on crack growth in concrete by FE and DIC
Xiangyi Zhu, Xudong Chen, Jun Lu and Xiangqian Fan

 
Abstract
    In this paper, the fracture characteristics of concrete specimens with different notch depths under three-point flexural loads are studied by finite element and fracture mechanics methods. Firstly, the concrete beams (the size is 700x100x150 mm) with different notch depths (a=30 mm, 45 mm, 60 mm and 75 mm respectively) are tested to study the influence of notch depths on the mechanical properties of concrete. Subsequently, the concrete beams with notch depth of 60 mm are loaded at different loading rates to study the influence of loading rates on the fracture characteristics, and digital image correlation (DIC) is used to monitor the strain nephogram at different loading rates. The test results show that the flexural characteristics of the beams are influenced by notch depths, and the bearing capacity and ductility of the concrete decrease with the increase of notch depths. Moreover, the peak load of concrete beam gradually increases with the increase of loading rate. Then, the fracture energy of the beams is accurately calculated by tail-modeling method and the bilinear softening constitutive model of fracture behavior is determined by using the modified fracture energy. Finally, the bilinear softening constitutive function is embedded into the finite element (FE) model for numerical simulation. Through the comparison of the test results and finite element analysis, the bilinear softening model determined by the tail-modeling method can be used to predict the fracture behavior of concrete beams under different notch depths and loading rates.
 
Key Words
    finite elements; notch depths; loading rates; digital image correlation (DIC); tail-modeling method; fracture energy
 
Address
Xiangyi Zhu: College of Water Conservancy and Hydropower Engineering, Hohai University, Nanjing 210098, China
Xudong Chen: College of Civil and Transportation Engineering, Hohai University, Nanjing 210098, China
Jun Lu: Department of Materials and Structural Engineering, Nanjing Hydraulic Research Institute, Nanjing, 210024, China
Xiangqian Fan: Department of Materials and Structural Engineering, Nanjing Hydraulic Research Institute, Nanjing, 210024, China
 

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