Ivo Černý¹, Václav Linhart²

Structural Durability & Health Monitoring, Vol.5, No.1, pp. 73-86, 2009, DOI:10.3970/sdhm.2009.005.073

Abstract The experimental programme described in the paper was aimed at an evaluation of fatigue crack growth (FCG) rate and threshold conditions in a reactor pressure vessel steel in laboratory air and in simple aqueous environment. Though the main target of the work was to enlarge the data basis for possible future needs of defect and risk assessment, an emphasis was put on an evaluation of crack growth mechanisms. It was shown that despite some recent works infirming crack closure phenomenon itself or methods of its evaluation, crack closure explained near-threshold fatigue crack behaviour in the specific case of the reactor… More >

C. Colombo¹, M. Guagliano^1,2, L. Vergani¹

Structural Durability & Health Monitoring, Vol.1, No.4, pp. 253-266, 2005, DOI:10.3970/sdhm.2005.001.253

Abstract In this paper the fatigue crack growth properties of a nitrided and shot-peened steel is dealt with: different peening intensities were considered and the resulting residual stresses measured by means of an X-ray diffractometer. Rotating bending fatigue tests were executed on specimens including a blind micro hole, acting as a pre-existent crack. The fracture surface of broken specimens was observed with a SEM to detect the crack growth initiation point. The run-out specimens were broken after the test and the presence of non-propagating cracks detected. The results allowed to determine the propagation threshold of the nitrided and shot peened material. 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 >

M. S. Alam¹, M.A. Wahab^1,2

Structural Durability & Health Monitoring, Vol.1, No.3, pp. 171-184, 2005, DOI:10.3970/sdhm.2005.001.171

Abstract Fatigue life of curved structural joints in ship structures under constant amplitude cyclic loading has been studied in this research. A new approach for the simulation of fatigue crack growth in welded joints has been developed and the concept has been applied to welded curved butt-joints. The phenomena of crack propagation and interface debonding can be regarded as the formation of new surfaces. Thus, it is possible to model these problems by introducing the mechanism of surface formation. In the proposed method, the formation of new surface is represented by interface element based on the interface surface potential energy. The… More >

S. N. Atluri¹

Structural Durability & Health Monitoring, Vol.1, No.1, pp. 1-20, 2005, DOI:10.3970/sdhm.2005.001.001

Abstract The solution of three-dimensional cracks (arbitrary surfaces of discontinuity) in solids and structures is considered. The BEM, developed based on the symmetric Galerkin BIEs, is used for obtaining the fracture solutions at the arbitrary crack-front. The finite element method is used to model the uncracked global (built-up) structure for obtaining the stresses in an otherwise uncracked body. The solution for the cracked structural component is obtained in an iteration procedure, which alternates between FEM solution for the uncracked body, and the SGBEM solution for the crack in the local finite-sized subdomain. In addition, some crack growth models are used to… More >

Akiyuki Takahashi^1,*, Takaki Fujiwara¹, Yuichi Shintaku²

The International Conference on Computational & Experimental Engineering and Sciences, Vol.22, No.4, pp. 170-170, 2019, DOI:10.32604/icces.2019.05151

Abstract This paper presents a Paris law-based cohesive zone model (CZM) for fatigue crack growth simulations to enable the consideration of the plasticity induced crack closure effect, which is known to be a source of substantial crack growth retardation. In order to avoid the addition of any redundant model parameters, the basic equation of the CZM is derived from the Paris law so that the CZM has only the parameters of Paris law. Thus, the parameters can be determined by referring the existing experimental data of the Paris law without any troublesome fitting processes. Only the parameter to be fitted is… More >

M. Kikuchi¹, Y. Wada², A. Utsunomiya³, Y. Li⁴

The International Conference on Computational & Experimental Engineering and Sciences, Vol.8, No.2, pp. 67-72, 2008, DOI:10.3970/icces.2008.008.067

Abstract Fatigue crack growth under mixed mode loading conditions is simulated using S-FEM. By using S-FEM technique, only local mesh should be re-meshed and it becomes easy to simulate crack growth. By combining with auto-meshing technique, local mesh is re-meshed automatically, and curved crack path is modeled easily. Three dimensional surface crack problem is solved by this technique. Pure mode I crack and slant crack problems are solved, and fatigue crack growth processes are simulated. The change of aspect ratio of surface crack and distributions of stress intensity factor along crack front are evaluated and discussed. More >

S. M. Beden¹, S. Abdullah¹, A. K. Ariffin¹

The International Conference on Computational & Experimental Engineering and Sciences, Vol.10, No.2, pp. 41-50, 2009, DOI:10.3970/icces.2009.010.041

Abstract Fatigue crack growth as consequence of service loads depends on many different contributing factors. This paper describes the fatigue crack growth behavior of metallic materials under cyclic loading towards standardizing the fatigue crack studies on metallic materials. For the simulation purpose, three points bend (TPB) with span to width ratio 8:1 and compact tension (CT) specimens geometry were used. There are many factors affecting the fatigue crack growth in structures, such as fatigue crack growth model, stress ratio, aspect ratio and type of geometry. The behavior of such cases is shown using different fatigue crack models (Paris, Forman and Austen).… More >

G. Renaud¹, M. Liao¹

The International Conference on Computational & Experimental Engineering and Sciences, Vol.1, No.2, pp. 87-92, 2007, DOI:10.3970/icces.2007.001.087

Abstract This paper presents a probabilistic crack growth model developed for the Holistic Structural Integrity Process (HOLSIP) framework. Statistical data, obtained from testing and fractographic analyses of 2024-T3 test coupons, were used to derive the fatigue crack growth material variability. Results showed the relative impact of material variability in the short and long crack regimes. Monte Carlo simulations showed good agreement between analytical life distributions and test results. More >

Jie Wang¹, Wei Jiang^1,*, Qi Wang¹

CMES-Computer Modeling in Engineering & Sciences, Vol.118, No.2, pp. 377-395, 2019, DOI:10.31614/cmes.2019.01836

Abstract A elastic-plastic fatigue crack growth (FCG) finite element model was developed for predicting crack growth rate under cyclic load. The propagation criterion for this model was established based on plastically dissipated energy. The crack growth simulation under cyclic computation was implemented through the ABAQUS scripting interface. The predictions of this model are in good agreement with the results of crack propagation experiment of compact tension specimen made of 304 stainless steel. Based on the proposed model, the single peak overload retardation effect of elastic-plastic fatigue crack was analyzed. The results shows that the single peak overload will reduce the accumulation… More >