Yiyu Lu¹, Chenpeng Song^1,2, Yunzhong Jia¹, Binwei Xia¹, Zhaolong Ge¹, Jiren Tang¹, Qian Li¹

CMES-Computer Modeling in Engineering & Sciences, Vol.105, No.1, pp. 69-86, 2015, DOI:10.3970/cmes.2015.105.069

Abstract In underground coal mines, hydrofracture can cause the increase of breathability in the fractured coal bed. When the hydrofracture crack propagates to the interface between the coal bed and the roof-floor stratum, the crack may enter roof-floor lithology, thus posing a limit on the scope of breathability increase and making it difficult to support the roof and floor board for subsequent coal mining. In this work, a two-dimensional model of coal rock bed that contains hydrofracture crack was constructed. Then an investigation that combines the fracture mechanics and the system of flow and solid in… More >

Ananthalakshmi K. Iyer¹, A. Rama Chra Murthy², Smitha Gopinath², Nagesh R. Iyer³

CMC-Computers, Materials & Continua, Vol.42, No.3, pp. 227-244, 2014, DOI:10.3970/cmc.2014.042.227

Abstract A non-linear fracture mechanics based approach is proposed to depict a typical fracture mechanism from initiation to growth, eventually leading to failure. This concept is developed for a lightly reinforced beam in flexure. The proposed model integrates the existing methodology of a Stress Intensity Factor equilibrium equation with the bridging forces developed in concrete cover and rebar. The model and solution algorithm outlined presents an elaborate understanding of the mechanism involved and is significant in predicting the behaviour of flexural members. The analysis is performed using MATLAB programming. The proposed approach ensures a maximum tolerable More >

S.M.O. Tavares¹, S.M. Häusler², P.M. Baiz³, P.M.S.T. de Castro¹, P. Horst² , M.H. Aliabadi³

Structural Durability & Health Monitoring, Vol.7, No.3, pp. 191-210, 2011, DOI:10.3970/sdhm.2011.007.191

Abstract This article is the second part of a two parts paper which presents, compares and discusses the different crack growth simulation models which were introduced for fatigue crack growth assessment during the DaToN project. In the first part, different simulation approaches were applied to determine a calibration of the stress intensity factors as a function of the crack length for a two stiffeners panel with a central crack. Due to the residual stress field promoted by the different manufacturing processes, its influence was included in the numerical models to determine the stress intensity factors. In… More >

S.M. Häusler¹, P.M. Baiz², S.M.O. Tavares³, A. Brot⁴, P. Horst¹, M.H. Aliabadi², P.M.S.T. de Castro³, Y. Peleg-Wolfin⁴

Structural Durability & Health Monitoring, Vol.7, No.3, pp. 163-190, 2011, DOI:10.3970/sdhm.2011.007.163

Abstract This article represents the first part of a two-part article which presents, compares and discusses the different crack growth simulation models which were introduced for fatigue crack growth assessment during the DaToN project. The project was funded by the EC within the 6th framework program and was specifically devoted to investigate innovative manufacturing techniques for metallic structures with special focus on the effects of residual stresses on the fatigue crack growth and residual strength behaviour. Within this first part the different simulation approaches, including the residual stress modelling approaches will be introduced and stress intensity… More >

A.Y.Chen, J. Lu

The International Conference on Computational & Experimental Engineering and Sciences, Vol.20, No.2, pp. 45-46, 2011, DOI:10.3970/icces.2011.020.045

Abstract The structural reliability of many brittle materials such as nanomaterials relies on the occurrence of intergranular, as opposed to transgranular, fracture in order to induce toughening by crack bridging. The current work examines the role of interface strength and grain size distribution in promoting intergranular fracture in order to maintain high toughening. A layered nanostructural 304SS sheet characterized by periodic distribution of nanocrystalline layers and micron-grained layers with graded grain size evolution has exhibited exceptional properties. The in situ SEM observations illustrate that an intergranular path and the consequent interface bridging process can be partitioned More >

E. Schnack¹, W. Weber², Y. Zhu³

CMES-Computer Modeling in Engineering & Sciences, Vol.74, No.1, pp. 1-38, 2011, DOI:10.3970/cmes.2011.074.001

Abstract Three dimensional fracture mechanics was done by several groups in the past. One topic for these three dimensional fracture mechanics is to consider re-entrant corners or wedges for isotropic material. An algorithm was developed in the past to compute the dominant eigenvalues for those problems with high accuracy. Based on Kondratiev's Lemma for elliptic boundary value problems it is started with the asymptotic for the displacement and stress distribution around these three dimensional corners. By considering the mixed boundary value problem, the field quantities in the vicinity of corner points are computed by using a… More >

G. Dhondt¹, D. Bremberg²

Structural Durability & Health Monitoring, Vol.6, No.3&4, pp. 305-328, 2010, DOI:10.3970/sdhm.2010.006.305

Abstract In a previous article the K-distritubion along the crack front of several mixed-mode specimens was investigated [Dhondt, Chergui, and Buchholz (2001)]. Both the modified virtual crack closure integral method and the quarter point element stress field method yielded results close to the available reference solutions in the literature [Murakami (1987)]. The present paper extends these results in two aspects. First, the meshing procedure used to obtain a focused mesh at the crack front is modified in order to deal with highly curved cracks. Secondly, the K-distribution along the initial crack is used to perform a More >

X.-H. Chen¹, Y.-W. Mai²

The International Conference on Computational & Experimental Engineering and Sciences, Vol.14, No.2, pp. 43-50, 2010, DOI:10.3970/icces.2010.014.043

Abstract A general elastoplastic fracture mechanics theory is proposed for applying the Essential-Work-of-Fracture (EWF) Method to quasi-static and impact toughness characterization. Advanced finite element modeling is developed to simulate the EWF Method using the crack-tip opening angle criterion (CTOA) and the constitutive relation of the material under consideration. For Poly(ethylene-terephlate) (PET) films, the load-displacement curves are calculated for the whole crack propagation process of deeply double-edge notched tensile specimens (DENT) with different ligament lengths so as to determine the total work, the essential work and the non-essential work of fracture. The effects of specimen gauge length More >

O. Allix¹, P. Kerfriden¹, P. Gosselet¹

CMES-Computer Modeling in Engineering & Sciences, Vol.55, No.3, pp. 271-292, 2010, DOI:10.3970/cmes.2010.055.271

Abstract We present numerical enhancements of a multiscale domain decomposition strategy based on a LaTIn solver and dedicated to the computation of the debounding in laminated composites. We show that the classical scale separation is irrelevant in the process zones, which results in a drop in the convergence rate of the strategy. We show that performing nonlinear subresolutions in the vicinity of the front of the crack at each prediction stage of the iterative solver permits to restore the effectiveness of the method. More >

Weiming Tao¹, Xingwang Yang¹

The International Conference on Computational & Experimental Engineering and Sciences, Vol.12, No.3, pp. 83-84, 2009, DOI:10.3970/icces.2009.012.083

Abstract Laser controlled separation of brittle materials like glass is a promising non-conven\discretionary {-}{}{}tional cutting method. It is an application of the crack propagation driven by thermal stresses induced by laser irradiation. In order to induce and control a crack propagating accurately along predetermined asymmetric trajectory in a brittle plate, an iterative method for effective laser scanning path was presented, and the effect of control parameters on the convergence was investigated. The iterative formulation for laser scanning path was based on PID control theory, which was composed of deviation of the crack from predetermined trajectory and… More >