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B.K.Raghuprasad¹, N.Lakshmanan², N.Gopalakrishnan², K.Muthumani²
Structural Durability & Health Monitoring, Vol.4, No.3, pp. 117-144, 2008, DOI:10.3970/sdhm.2008.004.117
Abstract The reduction in natural frequencies, however small, of a civil engineering structure, is the first and the easiest method of estimating its impending damage. As a first level screening for health-monitoring, information on the frequency reduction of a few fundamental modes can be used to estimate the positions and the magnitude of damage in a smeared fashion. The paper presents the Eigen value sensitivity equations, derived from first-order perturbation technique, for typical infra-structural systems like a simply supported bridge girder, modelled as a beam, an end-bearing pile, modelled as an axial rod and a simply supported plate as a continuum… More >

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G. Savaidis¹, N. Pitatzis¹, A. Savaidis¹, Ch. Zhang²
Structural Durability & Health Monitoring, Vol.4, No.3, pp. 145-160, 2008, DOI:10.3970/sdhm.2008.004.145
Abstract This paper presents an elastic-plastic finite element analysis of a circumferentially notched cylinder subjected to multiaxial non-proportional fatigue loading. Two different load combinations are investigated: (1) constant tension with cyclic torsion and (2) constant torsion with cyclic tension. The multilayer plasticity model of Besseling in conjunction with the von Mises yield criterion is applied to describe the elastic-plastic material behaviour. The parametrical study contains a coarse and a fine finite element mesh with and without mid-nodes as well as three different types of multilinear approximations of the material law, namely, a twenty-segments, a five-segments and a three-segments one. The comparison… More >

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1074

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P. Ramamurty Raju¹, B. Satyanarayana², K. Ramji³
Structural Durability & Health Monitoring, Vol.4, No.3, pp. 161-172, 2008, DOI:10.3970/sdhm.2008.004.161
Abstract This paper presents the details of method of sample size determination to estimate the characteristic fatigue life of aluminum alloy. The characteristic fatigue life of Aluminum alloy A356.2-T6 has been estimated by assuming a two parameter Weibull distribution model. A stepwise procedure is outlined to determine the number of specimens required at a predetermined stress amplitude to estimate the fatigue life within an acceptable error at a given probability and confidence level. The percentage of error is calculated at various probabilities and confidence levels (C.L). The probabilities considered are 50%, 90% and 95% whereas C.Ls considered are 90%, 95% and… More >

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2351

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M. M. Rahman¹, A. K. Arrifin², M. J. M. Nor², S. Abdullah²
Structural Durability & Health Monitoring, Vol.4, No.3, pp. 173-180, 2008, DOI:10.3970/sdhm.2008.004.173
Abstract This paper presents the fatigue analysis of spot-weld joints for automative structures to predict the lifetime and location of the weakest spot-welds due to the imposed loading conditions. A simple model was used to illustrate the technique of spot-weld fatigue analysis. Finite element model and analysis were carried out utilizing the finite element analysis commercial codes. Linear elastic finite element analysis was carried out to predict the stress state along the weld direction. It can be seen from the results that the predicted life greatly influence the sheet thickness, spot diameter and loading conditions of the model. Acquired results were… More >

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