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S.P.L. Leme¹, M.H. Aliabadi², L.M. Bezerra¹, P.W. Partridge¹
Structural Durability & Health Monitoring, Vol.3, No.3, pp. 121-132, 2007, DOI:10.3970/sdhm.2007.003.121
Abstract The coupled electromechanical behaviour of a thin piezoceramic sensor bonded to a stiffened panel subjected to membrane mechanical loadings is examined. The sensor is characterised by an electrostatic line model bonded to a damaged panel modelled by the dual boundary element method. Numerical results obtained demonstrate that the proposed method is capable of modelling changes in the signal output due to presence of cracks. Also presented is a numerical model for detecting fatigue crack growth in a stiffened panel using piezoceramic sensors. More >

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ARTICLE

Jean-Jacques Sinou¹
Structural Durability & Health Monitoring, Vol.3, No.3, pp. 133-164, 2007, DOI:10.3970/sdhm.2007.003.133
Abstract This paper aims to establish a damage identification methodology, called the Frequencies' Ratio Surfaces Intersection method (FRSI-method), for predicting not only the location and depth of the crack but also the crack orientation in a circular cross section beam. Two new criterions %Δ_i^cracked and %ψ_i,j^cracked that consider only the ratio of the natural frequencies of the cracked beam are introduced and discussed in order to detect the crack parameters. In order to avoid worse diagnostic, it is demonstrated that a robust identification of crack location is possible by investigating the emergence of extra antiresonance peaks on Frequency Response… More >

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730

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ARTICLE

S. Baragetti¹, F. Tordini²
Structural Durability & Health Monitoring, Vol.3, No.3, pp. 165-176, 2007, DOI:10.3970/sdhm.2007.003.165
Abstract The effect of a TiN PVD (Physical Vapor Deposition) coating on the fatigue behaviour of the titanium alloy Ti-6Al-4V was investigated. Fatigue tests were performed on coated and uncoated, both smooth and 120° V-notched, specimens in order to evaluate the influence of the coating on the substrate fatigue resistance. Numerical analyses were carried out in order to determine the stress distributions below the specimen surface and on the coating. Several coating elastic moduli were used in such calculations. The residual stress gradient induced by the coating process deposition and the substrate plasticization were also taken into account with FEM. The… More >

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643

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S. Beyer¹, Ch. Zhang², S. Hirose³, J. Sladek, V. Sladek⁴
Structural Durability & Health Monitoring, Vol.3, No.3, pp. 177-190, 2007, DOI:10.3970/sdhm.2007.003.177
Abstract This paper presents a hypersingular time-domain boundary element method (BEM) for transient dynamic crack analysis in two-dimensional (2-D), homogeneous, anisotropic and linear elastic solids. A finite crack in an infinite or a finite solid subjected to impact loading conditions is investigated. A combination of the classical displacement boundary integral equations (BIEs) on the external boundary and the hypersingular traction BIEs on the crack-faces is applied. The present BEM uses the time-domain dynamic fundamental solutions for anisotropic solids derived by Wang and Achenbach (1994). An explicit time-stepping scheme based on collocation method is developed. Numerical examples for computing the dynamic stress… More >

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667

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ARTICLE

Guocai Chai
Structural Durability & Health Monitoring, Vol.3, No.3, pp. 191-196, 2007, DOI:10.3970/sdhm.2007.003.191
Abstract Duplex stainless steels (DSS) are a group of steels consisting of approximately equal volume fraction of austenite and ferrite. In this study, the influences of the factors such as hydrogen, ferrite phase, cold deformation, grain size, and cluster due to the spinodal decomposition and precipitates or secondary phases in a super duplex stainless steel on the ductile to brittle transition (DBT) are investigated. Three types of DBT curves: toughness versus temperature, hardness and amount of precipitates, have been built to describe the DBT behavior in DSS. These curves are important to provide the information about the critical conditions or criteria… More >

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