Preliminary Approaches to Experimental and Numerical Study on Fast Crack Propagation and Crack Arrest

2009 ◽  
pp. 39-39-20 ◽  
Author(s):  
T Kanazawa ◽  
S Machida ◽  
T Teramoto
Keyword(s):  
Crack Propagation ◽  
Numerical Study ◽  
Crack Arrest

Short Crack Propagation Model Applied to Shot Peened Aluminium Alloys

2009 ◽  
Vol 65 ◽  
pp. 53-61 ◽  
Author(s):  
J. Solis ◽  
J. Oseguera-Peña ◽  
I. Betancourt
Keyword(s):  
Surface Roughness ◽  
Residual Stresses ◽  
Crack Propagation ◽  
Aluminium Alloys ◽  
Micromechanical Model ◽  
High Strength ◽  
Crack Arrest ◽  
Propagation Model ◽  
Safe Load ◽  
Compressive Residual Stresses

The Navarro-Rios micromechanical model was used to assess the bounds of two different damage zones: crack arrest region and crack propagation region of controlled shot peening (CSP) of high strength aluminium alloys. Performance of CSP in terms of fatigue resistance was investigated. This comparison indicated that CSP in terms of fatigue depends on the competition between its beneficial and detrimental products, i.e. surface roughness and compressive residual stresses respectively. The gathered information can be used for safe load determinations in design.

Numerical Study on Progressive Failure of the Marble Plate Based on the Thin-Layer Tri-Node Jointed Element

2011 ◽  
Vol 255-260 ◽  
pp. 1867-1872
Author(s):  
Jing Hua Qi ◽  
Zhen Nan Zhang ◽  
Xiu Run Ge
Keyword(s):  
Crack Propagation ◽  
Thin Layer ◽  
Numerical Study ◽  
Progressive Failure ◽  
Triangular Element ◽  
Compressive Loads ◽  
Joint Element ◽  
The Common ◽  
Edge Cracks ◽  
Good Agreement

In order to model the mechanical behavior of joints efficiently, a thin-layer tri-node joint element is constructed. The stiffness matrix of the element is derived in the paper. For it shares the common nodes with the original tri-node triangle element, the tri-node joint element can be applied to model the crack propagation without remeshing or mesh adjustment. Another advantage is that the cracked body is meshed without consideration of its geometry integrity and existence of the joints or pre-existed crack in the procedure of mesh generation, and then the triangular element intersected by the crack or joint is automatically transformed into the tri-node joint element to represent pre-existed cracks. These make the numerical simulation of crack propagation highly convenient and efficient. After CZM is chosen to model the crack tip, the mixed- energy simple criterion is used to determine whether the element is intersected by the extended crack or not, the extended crack is located in the model. By modeling the marble plates with two edge cracks subjected to the uniaxial compressive loads, it is shown that the numerical results are in good agreement with the experimental results, which suggests that the present method is valid and feasible in modeling rock crack propagation.

scholarly journals Dynamic Indentation Characteristics for Various Spacings and Indentation Depths: A Study Based on Laboratory and Numerical Tests

2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Jie Liu ◽  
Wen Wan ◽  
Yu Chen ◽  
Jun Wang
Keyword(s):  
Crack Propagation ◽  
Laboratory Tests ◽  
Indentation Depth ◽  
Numerical Study ◽  
Stress Concentrations ◽  
Dynamic Indentation ◽  
Indentation Force ◽  
Numerical Tests ◽  
Crack Tips ◽  
Rock Specimens

Laboratory and numerical study tests were conducted to investigate the dynamic indentation characteristics for various spacings and indentation depths. First, laboratory tests indicate that the increase in the indentation depth first resulted in enlarged groove volumes, caused by fiercer rock breakages between indentations for a fixed spacing; then, the groove volume slightly increased for further increase in indentation depth, whereas the increase in spacing restrained rock breakages and resulted in shrunken grooves. In addition, the numerical study agreed well with laboratory tests that small chips formed at the shallow part of the rock specimen at the early indentation stage, and then, larger chips formed by the crack propagation at deeper parts of the rock specimens when the indentation depth increased. With further increase in indentation depth, crushed powders instead of chips formed. Moreover, the numerical analysis indicates that crack propagation usually leads to the decrease of the indentation force and the dissipation of the stress concentrations at crack tips, whereas the cessation of crack propagation frequently resulted in the increase of the indentation force and the stress concentrations at crack tip with the increase in indentation depth.

Numerical Study of Crack Propagation in Stiff Clays

2006 ◽  
pp. 201-204
Author(s):  
Shan Yong Wang ◽  
K.C. Lam ◽  
Ivan W.H. Fung ◽  
Wan Cheng Zhu ◽  
Tao Xu ◽  
...  
Keyword(s):  
Crack Propagation ◽  
Numerical Study ◽  
Stiff Clays

KIa Crack Arrest Toughness Assessment Using Thermal Shock on Notched Disks

2004 ◽  
Author(s):  
Me´jido Hajjaj ◽  
Ste´phane Bugat ◽  
Clotilde Berdin ◽  
Philippe Bompard
Keyword(s):  
Crack Propagation ◽  
Thermal Shock ◽  
Static Analysis ◽  
Thermal Analyses ◽  
Crack Arrest ◽  
The Finite Element Method ◽  
Wave Interference ◽  
Shock Experiment ◽  
T Values ◽  
Arrest Toughness

The aim of the study is to validate the KIa-T curve on a thermal shock experiment performed on a notched disk (DTSE) taken from a A533-B type steel. Several experiments have been performed. Non linear thermal analyses were carried out using the finite element method in order to obtain the full thermal field within the specimen during crack propagation. The results obtained are in excellent agreement with the experimental results. The DTSE is also interpretated in static terms to compare the obtained KIa (T) values with the limit curve. Finally, dynamic F.E. simulations allow to estimate the influence of dynamic effects in the DTSE and thus validate the methodology. According to the computations, the crack arrested when dK/da>0 and dKd/da = 0. The comparison between stress intensity factor computed from elastic-static analysis (or dynamic) and RCC-M code demonstrated the conservatism of the approach. Then static analysis is sufficient to analyse the result, since no wave interference with the crack propagation was identified.

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