G. Davì¹, A. Milazzo¹

Structural Durability & Health Monitoring, Vol.2, No.3, pp. 177-182, 2006, DOI:10.3970/sdhm.2006.002.177

Abstract An alternative single domain boundary element formulation and its numerical implementation are presented for the analysis of two-dimensional cracked bodies. The problem is formulated employing the classical displacement boundary integral representation and a novel integral equation based on the stress or Airy's function. This integral equation written on the crack provides the relations needed to determine the problem solution in the framework of linear elastic fracture mechanics. Results are presented for typical problems in terms of stress intensity factors and they show the accuracy and efficiency of the approach. More >

L. Susmel^1,2, D. Taylor²

Structural Durability & Health Monitoring, Vol.2, No.2, pp. 91-108, 2006, DOI:10.3970/sdhm.2006.002.091

Abstract This paper reports on an attempt to systematically re-interpret the conventional multiaxial fatigue criteria in terms of the Theory of Critical Distances: in the present study the criteria proposed by Crossland, Dang Van, Papadopoulos, Matake, McDiarmid, respectively, and the so-called Modified W\"{o}hler Curve Method were considered. The procedure devised to re-interpret the above methods in terms of the Theory of Critical Distances was based on the following two assumptions: (i) the critical distance is a material constant to be determined under fully-reversed uniaxial fatigue loading; (ii) the presence of non-zero mean stresses as well as of non-zero out-of-phase loading has… More >

S. Glodež¹, B. Aberšek¹, G. Fajdiga², J. Flašker²

Structural Durability & Health Monitoring, Vol.1, No.3, pp. 215-224, 2005, DOI:10.3970/sdhm.2005.001.215

Abstract A computational model for simulation of surface and subsurface initiated fatigue crack growth due to contact loading is presented. The model is based on fracture mechanics theory where the required materials properties are obtained from common fatigue tests. For computational simulations an equivalent model of two contacting cylinders is used instead of simulating the actual contact of mechanical elements. The discretised model with the initial crack on or under the surface is then subjected to normal contact pressure, which takes into account the elasto-hydro-dynamic (EHD) lubrication conditions, and tangential loading due to friction between contacting surfaces. The model considers also… More >

A. Rama Ch,ra Murthy¹, G.S. Palani¹, Nagesh R. Iyer¹

Structural Durability & Health Monitoring, Vol.1, No.3, pp. 203-214, 2005, DOI:10.3970/sdhm.2005.001.203

Abstract This paper presents an improved Wheeler residual stress model for remaining life prediction of the cracked structural components under variable amplitude loading. The improvement to the Wheeler residual stress model is in two folds. One is expressions for the shaping exponent, which are generally obtained through experiments. Another is calculation of effective plastic zone size to incorporate the sequent effects under tensile-compressive overloading. The remaining life prediction has been carried out by employing the linear elastic fracture mechanics (LEFM) principles. Studies on remaining life prediction of cracked plate panels subjected to tensile-compressive overloading have been carried out for validating the… More >

Wei Wei¹, Qingsheng Yang^2,*, Xia Liu², Xiaoqiao He^3,*, Kim-Meow Liew³

CMES-Computer Modeling in Engineering & Sciences, Vol.115, No.3, pp. 387-409, 2018, DOI: 10.3970/cmes.2018.01856

Abstract In this paper, by introducing a chemical field, the J-integral formulation is presented for the chemo-mechanical coupled medium based on the laws of thermodynamics. A finite element implementation of the J-integral was performed to study the mode I chemo-mechanical coupled fracture problem. For derivation of the coupled J-integral, the equivalent domain integral (EDI) method was applied to obtain the mode I J-integral, with expression of the area integrals based on constitutive relationships of a linear elastic small deformation for chemo-mechanical coupling, instead of the finite deformation problem. A finite element procedure is developed to compute the mode I J-integral, and… More >

Wanlin Guo

The International Conference on Computational & Experimental Engineering and Sciences, Vol.22, No.4, pp. 184-186, 2019, DOI:10.32604/icces.2019.04905

Abstract The fracture mechanics theories have been developed actively for several decades, and have been successful for many specific engineering applications and serves as the fundamental for damage tolerant design of structures. In 1957, William and Irwin obtained the stress intensity factor K dominated solution of the singular stress and strain fields near crack tip in linear elastic plate, provided the theoretical basis for linear elastic fracture mechanics. In 1968, the famous J-integral dominated HRR solution for plane stress and plane strain cracked plates of power law hardening materials has long served as the fundamental of elastic-plastic fracture mechanics and similar… 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 and ligament length on crack… More >

E. Schnack¹, K. Kolk², A. Dimitrov³

The International Conference on Computational & Experimental Engineering and Sciences, Vol.8, No.3, pp. 107-114, 2008, DOI:10.3970/icces.2008.008.107

Abstract In fracture mechanics, corner and wedge singularities have to be considered for two- and three-dimensional problems in isotropic and layered anisotropic continua. To investigate the behaviour of crack propagation starting from corners and edges the information about stress asymptotics in the vicinity of three-dimensional corner points is needed [1]. Thus, in this paper two aspects are studied: the interface crack in layered anisotropic materials with re-entrant corners and surface cracks in homogeneous isotropic continua. Moreover a strategy is presented to model such surface breaking cracks efficiently within a numerical 3D simulation [2]. To study the effect of geometrical singularities generalized… More >

J. Toribio¹, V. Kharin²

The International Conference on Computational & Experimental Engineering and Sciences, Vol.7, No.3, pp. 135-140, 2008, DOI:10.3970/icces.2008.007.135

Abstract This paper deals with the meaning and significance of the fracture mechanics approach to hydrogen assisted cracking, analyzing the question of K-dominance not only over the purely mechanical aspects, but also over the environmental (physicochemical) events. Two key factors able to violate the uniqueness of the crack growth kinetics curve v = v(K) are discussed: the role of far field (the stress-strain field which is not K-dominated) and the effect of the history of hydrogenation and crack growth. The far field is shown to have a minor effect on near-tip hydrogen diffusion, and thus it can only widen the scatter… More >

Waruna Seneviratne¹, John Tomblin², Suranga Gunawardana³

The International Conference on Computational & Experimental Engineering and Sciences, Vol.4, No.2, pp. 81-86, 2007, DOI:10.3970/icces.2007.004.081

Abstract An experimental study was conducted to investigate the use of fracture mechanics to predict failure initiation of adhesive joints. Most practical plane fracture problems are mixed mode and failure initiation of adhesive joints is a result of such conditions. It is widely accepted that a useful method for characterizing the toughness of bonded joints is to measure the fracture toughness; energy per unit area needed to produce failure. For a given adhesive, mode mixity has a dependency towards fracture toughness and fracture toughness is directly associated with stress. Main goal in this investigation was to demonstrate the capability of utilizing… More >