Numerical Studies of End Effect on Crack Propagation Behavior of Brittle Specimen Containing Pre-Existing Crack under Uniaxial Compression

2007 ◽  
Vol 353-358 ◽  
pp. 1049-1052
Author(s):  
Ming Li Huang ◽  
Shan Yong Wang ◽  
Wei Lu ◽  
Wan Cheng Zhu
Keyword(s):  
Crack Propagation ◽  
Uniaxial Compression ◽  
Process Analysis ◽  
Failure Process ◽  
End Effect ◽  
Wing Crack ◽  
Propagation Length ◽  
Propagation Behavior ◽  
Numerical Studies ◽  
Crack Propagation Process

In this paper, a Material Failure Process Analysis code (MFPA2D) was employed to investigate the interaction of end effect zone of specimen with the wing crack propagation inside the brittle specimen containing pre-existing flaws under uniaxial compression comparing with the experimental results. The numerical results show that the shorter the distance between the pre-existing flaw and the specimen's end , the slower the crack propagation process and the shorter wing propagation length is , and vice versa. In addition, the end effect zone was also influenced by the wing crack propagation.

Analysis of Failure Mode and Propagation for Crack in Uniaxial Compression

2012 ◽  
Vol 166-169 ◽  
pp. 2929-2932
Author(s):  
Ya Zhen Sun ◽  
Xiao Xing Zhai ◽  
Jie Min Liu
Keyword(s):  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Failure Mode ◽  
Uniaxial Compression ◽  
Process Analysis ◽  
Failure Process ◽  
Inclined Crack ◽  
Wing Crack ◽  
Dimensionless Stress

This paper analyzed the failure mode for crack in uniaxial compression according to the stress intensity factor, and obtain that the failure mode for crack in uniaxial compression is compression-shear. The wing crack was deformed, after the crack tip initiate. By analyzing the dimensionless stress intensity factor, we obtain that the failure mode for wing crack in uniaxial compression is tension-shear, and we obtain that the dimensionless stress intensity factor for wing crack decreased with inclined angle increased. The inclined crack propagation in uniaxial compression was numerically studied using rock failure process analysis code (rfpa), and obtain that one inclined crack in uniaxial compression formed mode I offset crack parallel to load direction in the end. The numerical results of failure mode are accordance with stress intensity factor.

scholarly journals Investigation of the Blast-Induced Crack Propagation Behavior in a Material Containing an Unfilled Joint

2020 ◽  
Vol 10 (13) ◽  
pp. 4419
Author(s):  
Peng Xu ◽  
Renshu Yang ◽  
Yang Guo ◽  
Zhicheng Guo
Keyword(s):  
Shear Stress ◽  
Stress Concentration ◽  
Crack Propagation ◽  
Wing Crack ◽  
Reflected Wave ◽  
Propagation Behavior ◽  
Dilatational Wave ◽  
Propagating Crack ◽  
Vertical Joint ◽  
Crack Propagation Behavior

This study uses a dynamic caustic technique to study the crack propagation in a medium containing an unfilled joint under blasting. The results show that for the medium containing a vertical unfilled joint, the reflected dilatational wave from the joint tends to suppress both the K I d and the velocity of the opposite propagating crack. However, for the medium containing an oblique joint, the reflected wave from the joint increases K II d , and induces the opposite propagating crack deflect from its original path. Compared with the medium with a vertical joint, the wing cracks are more easy to initiate at the oblique joint where a significant stress concentration is formed under the diffraction of the blast wave. Combined with numerical results, it is found that the wing crack deflects in the clockwise direction when the shear stress was negative, and it turns to counterclockwise when the shear stress was positive.

Crack Growth Mechanisms from 3-D Surface Flaw with Varied Dipping Angle under Uniaxial Compression

2007 ◽  
Vol 353-358 ◽  
pp. 2353-2356 ◽  
Author(s):  
Y.S.H. Guo ◽  
R.H.C. Wong ◽  
K.T. Chau ◽  
Wei Shen Zhu ◽  
Shu Cai Li
Keyword(s):  
Crack Initiation ◽  
Crack Propagation ◽  
Crack Growth ◽  
Uniaxial Compression ◽  
Axial Loading ◽  
Growth Direction ◽  
Surface Flaw ◽  
Growth Mechanisms ◽  
Wing Crack ◽  
Ae Energy

A number of instability problems in rock engineering projects are caused by crack propagation. However, crack growth mechanisms from 3-dimentional flaw are not fully understood, in particular for 3-D flaw case with varied dipping angle. This study focuses on 3-D surface flaw using real rock specimens containing a flaw with varied inclination angle α from axial loading and dipping angle γ from specimen surface under uniaxial compression. Acoustic emission technique was used for tracing the initiation and growth of micro-cracks inside of specimen. It was found that crack growth process is affected by the dipping angle γ of the 3-D flaw. When dipping angle γ ≠ 90º, the thickness of rock above the flaw plane is thinner than that of below the flaw plane. As a result, compressive crack and wing crack initiated easily from the thinner flaw tips. And, the normalized stress for crack initiation σi /σc, AE events and the AE energy for crack growth decreases with the dipping angle γ. However, for γ = 90º, the thickness of rock above and below of the flaw tips is the same, it was observed that anti-wing crack (crack growth direction opposite to wing crack) initiated first at a certain place away from the flaw tips, then wing crack and compressive crack emerged at the late stage. For this case, the stress σi /σc, AE events and the AE energy for crack initiation and propagation are at a high value. Thus, for rock mass contains flaws geometry with small dipping angle, some problems of crack propagation may be induced easily during excavation.

The Development of Fatigue Crack Propagation Models for Engineering Applications at Elevated Temperatures

1975 ◽  
Vol 97 (4) ◽  
pp. 289-297 ◽  
Author(s):  
B. Tomkins
Keyword(s):  
Fatigue Crack ◽  
Crack Propagation ◽  
Fatigue Crack Propagation ◽  
Elevated Temperatures ◽  
Failure Process ◽  
Propagation Models ◽  
Creep Fatigue ◽  
Creep Cavitation ◽  
Crack Propagation Process

The value of modelling the fatigue crack propagation process is discussed and current models are examined in the light of increasing knowledge of crack tip deformation. Elevated temperature fatigue is examined in detail as an area in which models could contribute significantly to engineering design. A model is developed which examines the role of time-dependent creep cavitation on the failure process in an interactive creep-fatigue situation.

Crack Propagation Behavior of Asphalt Concrete; Part I: A Study into Influence of Different Materials

2008 ◽  
Vol 385-387 ◽  
pp. 297-300
Author(s):  
Tao Xie ◽  
Ze Zhong Jiang ◽  
Yan Jun Qiu ◽  
Bo Lan
Keyword(s):  
Crack Propagation ◽  
Fracture Resistance ◽  
Failure Process ◽  
Asphalt Mixtures ◽  
Asphalt Pavements ◽  
Cracking Behavior ◽  
Strain Behavior ◽  
Propagation Behavior ◽  
Maintenance And Rehabilitation ◽  
Asphalt Materials

The fracture resistance of asphalt materials significantly influences the service life of asphalt pavements and consequently affects the maintenance and rehabilitation costs of the pavement network. Therefore, there is significant interest in understanding the mechanism of fracture in asphalt pavements and in developing analysis tools that would lead to the selection of asphalt materials with increased fracture resistance. Study of cracking behavior of asphalt mixtures should be conducted in a micro-scale level to have a real simulation of crack propagation. Using SIEMENS SOMATOM plus X-ray CT (computerized tomography) and multi-functional testing rig, a dynamic observation of cracking propagation of hot mix asphalt was conducted in this research. Failure process under compressive pressure was recorded using CT images and CT numbers. The direct responses in density change of Marshall Samples under a CT-compressive process are change of CT numbers. Cracking propagation in the samples can be clearly observed and failure mode and stress-strain behavior can then be simulated. The tests reported provide important theoretical fundamentals to study the cracking behavior and failure mechanism of asphalt mixtures.

Influence of wing crack propagation on the failure process and strength of fractured specimens

2022 ◽  
Vol 81 (1) ◽  
Author(s):  
Hengtao Yang ◽  
Hang Lin ◽  
Yifan Chen ◽  
Yixian Wang ◽  
Yanlin Zhao ◽  
...  
Keyword(s):  
Crack Propagation ◽  
Failure Process ◽  
Wing Crack

Numerical Simulation of Thermal Induced Crack Propagation in Laminated Composites

2008 ◽  
Vol 575-578 ◽  
pp. 886-891
Author(s):  
Tao Xu ◽  
Ju Ying Yang ◽  
Chun An Tang ◽  
Shi Bin Tang
Keyword(s):  
Crack Propagation ◽  
Lower Layer ◽  
Laminated Composite ◽  
Time Interval ◽  
Element Formulation ◽  
Temperature Decrease ◽  
Layered Composites ◽  
Propagation Behavior ◽  
Crack Propagation Process ◽  
Set Up

A coupled thermo-mechanical model is employed to analyze the thermo-mechanical behavior of a widely used laminated composite subject to temperature decrease at service conditions. Three sets of governing equations, i.e. heat transfer, thermo-mechanical deformation and damage evolution are respectively described in the model. These equations are then assembled into a coupled matrix equation using finite element formulation and then solved simultaneously at each time interval. A numerical model of two layered composites with some preexisting equal-spacing cracks along the interface in the lower layer is set up to investigate the thermal induced crack propagation due to temperature decrease. Results are presented in the form of crack propagation process in stress profiles and discussed. Numerical simulations show that the crack propagation behavior of the composites is closely dependent on the physico-mechanical properties of two layers and preexisting cracks. It is found that thermal induced cracks penetrate into the upper layer and grow in the upper layer due to the low strength of the upper layer when the model is subject to uniform temperature decrease.

Sign in / Sign up

Export Citation Format

Share Document