Fracture process zone associated with mixed mode fracture of SiCw/Al2O3

1994 ◽  
Vol 177 ◽  
pp. 26-35 ◽  
Author(s):  
Chang-Te Yu ◽  
Albert S. Kobayashi
2020 ◽  
Vol 44 (10) ◽  
pp. 1417-1445 ◽  
Author(s):  
Yingnan Wang ◽  
Hieu T. Tran ◽  
Giang D. Nguyen ◽  
Pathegama G. Ranjith ◽  
Ha H. Bui

1990 ◽  
Vol 116 (7) ◽  
pp. 1560-1579 ◽  
Author(s):  
B. M. Liaw ◽  
F. L. Jeang ◽  
N. M. Hawkins ◽  
A. S. Kobayashi

2017 ◽  
Vol 52 (4) ◽  
pp. 239-248 ◽  
Author(s):  
Ahmad Ghasemi-Ghalebahman ◽  
Javad Akbardoost ◽  
Yaser Ghaffari

The aim of this study was to examine the effect of size on the mixed-mode fracture toughness of quasi-brittle nanocomposites with the help of modified maximum tangential stress criterion. The literature reveals that the effect of size on mixed-mode fracture behavior of brittle nanocomposites has not been well investigated previously using modified maximum tangential stress criterion. The studied nanocomposites were made of epoxy resin reinforced with 7 wt%, 20–30 nm nanosilica. The accuracy of the method was assessed by taking into account the high-order terms of Williams series expansion along with finite element over-deterministic method. To investigate the effect of size on fracture toughness, a number of three-point semi-circular bending tests with different radii and four angles of edge–crack orientation were conducted and subjected to mixed-mode loading. The size of fracture process zone and apparent fracture toughness ( Kc) were also evaluated as a function of sample size. Experimental results showed that the proposed approach can accurately predict the fracture behavior of studied nanocomposites.


2014 ◽  
Vol 584-586 ◽  
pp. 1780-1788
Author(s):  
Xin Pu Shen ◽  
Xiao Chun Wang

Concerning on the modelling of quasi-brittle fracture process zone at interface crack of quasi-brittle materials and structures, typical constitutive models of mixed mode interface cracks were compared. Numerical calculations of the constitutive behaviours of selected models were carried out at local level. Aiming at the simulation of quasi-brittle fracture of concrete-like materials and structures, the emphases of the qualitative comparisons of selected cohesive models are focused on: (1) the fundamental mixed mode fracture behaviours of selected interface crack models; (2) dilatancy properties of the selected models under mixed mode fracture loading conditions.


Materials ◽  
2020 ◽  
Vol 13 (14) ◽  
pp. 3203
Author(s):  
Guodong Li ◽  
Zhengyi Ren ◽  
Jiangjiang Yu

The size of the fracture process zone (FPZ) has significance for studying the fracture mechanism and fracture characteristics of concrete. This paper presents the method of assessing the FPZ of Mixed-Mode I-II for quasi-static four-point shearing concrete beams with pre-notched by Lagrangian strain profiles from digital image correlation (DIC). Additionally, it explores the influences of volume rates of the coarse aggregate of 0%, 28%, 48%, and 68%, and the specific surface areas of 0.12 m2/kg, 0.15 m2/kg, and 0.26 m2/kg on the size of the FPZ. It shows that the size of FPZ in four-point shearing concrete beam can be characterized by the displacement field and strain field using DIC. The size of FPZ conforms to linear positive correlation with the volume rate of coarse aggregate, and linear negative correlation with the specific surface area of coarse aggregate. It presents that the crack initiation of the four-point shearing beam with the pre notch is dominated by mode I load, and the propagation and fracture of Mixed-Mode I-II cracks are caused by the combined effect of Mode I and Mode II loading.


1994 ◽  
Vol 61 (4) ◽  
pp. 815-821 ◽  
Author(s):  
Z. K. Guo ◽  
A. S. Kobayashi ◽  
N. M. Hawkins

The development of the fracture process zone associated with subcritical crack growth in a three-point bend concrete specimen with an off-centered, single-edged precrack was monitored with moire interferometry. The applied load and the crack opening and sliding displacements together with a finite element model of the concrete specimen were used to determine the crack closing stress due to aggregate bridging. Under this mixed-mode fracture, aggregate interlocking increased the crack closing stresses in the fracture process zone and hence the load carrying capacity of the concrete specimen. The dissipated energy rate in the fracture process zone also increased with aggregate interlocking.


2018 ◽  
Vol 5 (1) ◽  
pp. 171374 ◽  
Author(s):  
Bao Xiankai ◽  
Tao Meng ◽  
Zhao Jinchang

Based on the engineering background of water dissolving mining for hydrocarbon storage in multi-laminated salt stratum, the mixed mode fracture toughness and fracture trajectory of gypsum interlayers soaked in half-saturated brine at various temperatures (20°C, 50°C and 80°C) were studied by using CSNBD (centrally straight-notched Brazilian disc) specimens with required inclination angles (0°, 7°, 15°, 22°, 30°, 45°, 60°, 75°, 90°) and SEM (scanning electron microscopy). The results showed: (i) The fracture load of gypsum specimens first decreased then increased with increasing inclination angle, due to the effect of friction coefficient. When soaked in brine, the fracture toughness of gypsum specimens gradually decreased with increasing brine temperature. (ii) When soaked in brine, the crystal boundaries of gypsum separated and became clearer, and the boundaries became more open between the crystals with increasing brine temperature. Besides, tensile micro-cracks appeared on the gypsum crystals when soaked in 50°C brine, and the intensity of tensile cracks became more severe when soaking in 80°C brine. (iii) The experimental fracture envelopes derived from the conventional fracture criteria and lay outside these conventional criteria. The experimental fracture envelopes were dependent on the brine temperature and gradually expanded outward as brine temperature increases. (iv) The size of FPZ (fracture process zone) was greatly dependent on the damage degree of materials and gradually increased with increase of brine temperature. The study has important implication for the control of shape and size of salt cavern.


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