Determination of the mixed mode Ⅰ/Ⅱ fracture characteristics of heat-treated granite specimens based on the extended finite element method

Author(s):  
You Wu ◽  
Tubing Yin ◽  
Xiaosong Tan ◽  
Dengdeng Zhuang
Materials ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 1993
Author(s):  
Lei Gao ◽  
Xingkuan Deng ◽  
Ye Zhang ◽  
Xue Ji ◽  
Qiang Li

Cold recycled mixture (CRM) has been widely used around the world mainly because of its good ability to resist reflection cracking. In this study, mixed-mode cracking tests were carried out by the designed rotary test device to evaluate the cracking resistance of CRM. Through the finite element method, the heterogeneous model of CRM based on its meso-structure was established. The cracking process of CRM was simulated using the extended finite element method, and the influence of different notch lengths on its anti-cracking performance was studied. The results show that the mixed-mode fracture test method can effectively evaluate the cracking resistance of CRM by the proposed fracture parameters. The virtual tests under three of five kinds of mixed-cracking modes have good simulation to capture the cracking behavior of CRM. The effect of notch length on the initial crack angle and the crack propagation process of the CRM is mainly related to the distribution characteristics of its meso-structure. With the increase of the proportion of Mode II cracking, the crack development path gradually deviates, and the failure elements gradually increase. At any mixed-mode level, there is an obvious linear relationship between the peak load, fracture energy, and the notch length.


Author(s):  
Xin-Ting Miao ◽  
Chang-Yu Zhou ◽  
Xiao-Hua He

Extended finite element method (XFEM) is adopted in this paper to study crack growth path and loading capability for modified compact tension shear (CTS) specimen with stop hole ahead of crack tip. Elliptical stop holes with different values of b/h are considered, where b and h are radii of the ellipse parallel and vertical to the crack. When b/h is 1 (circle stop hole), the locations of crack initiation turn clockwise gradually as the loading angle β (angle between the loading direction and the crack plane) decreases. When b/h is not equal to 1 (elliptical stop hole), the locations of crack initiation are all near the long axis end point of the ellipse no matter what the mode mixity is. Curves of load-COD and ultimate loads are presented for different mixed mode loadings, it can be obtained that for mode I dominant crack loading capability increases, though for mode II dominant crack loading capability decreases due to the stop hole technique. For mode I dominant crack the loading capability increases as the value of b/h decreases, and for mode II dominant crack the trend of loading capability with b/h changes gradually oppositely. The difference of crack initiation locations for different stop holes is due to the stress concentration considering both curvatures and the loading modes. And the difference of loading capability for specimens with stop holes under different mixed mode loadings is due to the shear action due to the discrepancy between the positive and negative stresses. Therefore, stop hole technique can be used to change the crack initiation location in order to avoid the important component and improve the loading capability by choosing an appropriate hole shape.


Author(s):  
Elena Benvenuti ◽  
Nicola Orlando

AbstractWe propose a formulation for tracking general crack paths in elastodamaging materials without mesh adaptivity and broadening of the damage band. The idea is to treat in a unified way both the damaging process and the development of displacement discontinuities by means of the regularized finite element method. With respect to previous authors’ contributions, a novel damage evolution law and an original crack tracking framework are proposed. We face the issue of mesh objectivity through several two-dimensional tests, obtaining smooth crack paths and reliable structural results.


Sign in / Sign up

Export Citation Format

Share Document