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 factor results will be presented… More >

S. Abdullah¹, S. M. Beden, A. K. Ariffin, N. A. Al-Asady

Structural Durability & Health Monitoring, Vol.5, No.2, pp. 109-132, 2009, DOI:10.3970/sdhm.2009.005.109

Abstract This paper presents a study on fatigue crack growth modelling of thin walled tube aluminium alloy with circumferential crack under constant and variable amplitude loadings. Three fatigue crack growth models were investigated for this purpose, i.e. Walker, Forman and NASGRO. The results showed the differences in the fatigue crack growth simulation under both loading types, although, they have the same stress ratio for the maximum value. Subsequently, it was found that, different models gave different fatigue crack growth behaviour. In another case, many factors were identified towards the fatigue crack growth affection in structures. Hence, an initial crack length and… More >

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 >

G. Bertrand¹

Structural Durability & Health Monitoring, Vol.1, No.3, pp. 185-192, 2005, DOI:10.3970/sdhm.2005.001.185

Abstract Each maintenance strategy demands for the definition of an inspection threshold and further inspection intervals. A general criterion for the calculation of the time to first inspection is high probability of detection of a certain crack size and low failure probability in case a predicted crack size was not detected. The proposed method demonstrates that a top down analysis of crack development from critical sizes to detectable sizes reveals an economic benefit with respect to the frequency of inspections. The dispersion of fatigue stress cycles at rupture obtained from component tests at riveted lap joints is transformed to the distribution… 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 >

T. Sakai, W. Li, B. Lian, N. Oguma

The International Conference on Computational & Experimental Engineering and Sciences, Vol.16, No.1, pp. 7-8, 2011, DOI:10.3970/icces.2011.016.007

Abstract Long term use of mechanical products provides us a lot of positive environmental effects such as saving resources, saving energy, reducing environmental load to globe and reducing the industrial wastes. Thus, fatigue property of metallic materials in very high cycle regime such as gigacycles has been a new important subject to ensure the long durability of actual mechanical structures during the latest decades. From this point of view, fatigue tests in the long life regime were performed for various kinds of metallic materials by many researchers and a series of experimental results were reported. One of most typical aspect in… More >

Ying Wang*, Zhen Wang

The International Conference on Computational & Experimental Engineering and Sciences, Vol.22, No.4, pp. 176-176, 2019, DOI:10.32604/icces.2019.05665

Abstract Due to stress concentration as well as welding residual stress, fracture due to vehicle fatigue loads is easy to occur in the weld and its adjacent position of long-span bridge, especially at the toe of weld between the U-rib and orthotropic steel bridge deck. In order to investigate the fatigue crack propagation mechanism of the toe of weld in long-span bridge, a multi-scale finite element model including the whole bridge, local components, the welding details and cracks was established firstly. And then, based on birth and death element technology, the welding heat and structural coupling process simulation was carried out… More >