Kamran Nikbin¹

Structural Durability & Health Monitoring, Vol.3, No.1, pp. 51-68, 2007, DOI:10.3970/sdhm.2007.003.051

Abstract Weldments and welded regions of components are likely to see failure at elevated temperatures earlier than homogenous parent material. In some cases variable loading could also introduce creep/fatigue crack growth. These weld regions not only contain variable creep properties but are likely to contain residual stresses which could relax in time. There are three key factors which may determine a successful outcome for remaining life assessment of engineering components containing residual stresses in the vicinity of welds. The first is standardized testing and measurement procedures. The second is the development of appropriate and accurate correlating… More >

M. M. Rahman¹, A. K. Ariffin¹, S. Abdullah¹, N. Jamaludin¹

Structural Durability & Health Monitoring, Vol.3, No.1, pp. 1-14, 2007, DOI:10.3970/sdhm.2007.003.001

Abstract A modern computational approach based on finite element analysis for durability assessment in a two-stroke free piston linear engine component using the variable amplitude loadings is presented. This paper describes the finite element analysis techniques to predict the fatigue life and identify the critical locations of the component. The effect of mean stress on the fatigue life is also investigated. The finite element modeling and analysis has been performed using a computer-aided design and a finite element analysis software package, and the fatigue life prediction was carried out using finite element based fatigue life prediction… More >

RamanaM. Pidaparti¹

Structural Durability & Health Monitoring, Vol.2, No.3, pp. 131-148, 2006, DOI:10.3970/sdhm.2006.002.131

Abstract This paper provides an overview of the computational intelligence methods developed for the structural integrity assessment of aging aircraft structures. Computational intelligence techniques reviewed include artificial neural networks, inverse neural network mapping, wavelet based image processing methods, genetic algorithms, spectral element methods, and particle swarm optimization. Multi-site damage, corrosion, and corrosion-fatigue damage in aging aircraft is specifically discussed. Results obtained from selected computational intelligence methods are presented and compared to the existing alternate solutions and experimental data. The results presented illustrate the applicability of computational intelligence methods for assessing the structural integrity of aging aircraft More >

A. Soprano¹, F. Caputo¹

Structural Durability & Health Monitoring, Vol.2, No.1, pp. 51-68, 2006, DOI:10.3970/sdhm.2006.002.051

Abstract This work describes the results of the experience acquired by the authors during their participation to some among the European research programs with the aim to develop a probabilistic risk assessment procedure to analyse the spreading of fatigue-induced damage in typical aeronautical components. The several steps of the procedure are pointed out, and especially the modelling of the damage evolutionary process; the initiation and the transitional probabilities, which characterize the passage from one damage level to a higher one, are fully characterized and their dependence from time and from the damage state of surrounding zones More >

Jae Bong Lee¹, Jai Hak Park¹, Sung Ho Lee², Hong-Deok Kim², Han-Sub Chung²

CMES-Computer Modeling in Engineering & Sciences, Vol.11, No.1, pp. 9-16, 2006, DOI:10.3970/cmes.2006.011.009

Abstract The growth of stress corrosion cracks in steam generator tubes is predicted using the Monte Carlo simulation and statistical approaches. The statistical parameters that represent the characteristics of crack growth and crack initiation are derived from in-service inspection (ISI) non-destructive evaluation (NDE) data. Based on the statistical approaches, crack growth models are proposed and applied to predict crack distribution at the end of cycle (EOC). Because in-service inspection (ISI) crack data is different from physical crack data, a simple method for predicting the physical number of cracks from periodic in-service inspection data is proposed in More >

P. Horst¹

Structural Durability & Health Monitoring, Vol.1, No.1, pp. 49-66, 2005, DOI:10.3970/sdhm.2005.001.049

Abstract The paper presents a Monte Carlo Simulation method for the assessment of Multiple Site Damage (MSD) and a subsequent attempt to find a way to interpret intermediate results of the Monte Carlo Simulation with respect to the criticality of scenarios. The basic deterministic part of the model is based on the compounding method, which is used in order to gain an acceptable computational effort. Some examples illustrate features of MSD scenarios and this allows to check an approach for feature detection via Wavelet transforms. This Wavelet transform approach shows some positive results in the interpretation More >

Marcello Lappa ¹

CMC-Computers, Materials & Continua, Vol.2, No.1, pp. 51-64, 2005, DOI:10.3970/cmc.2005.002.051

Abstract A possible approach for the investigation of a number of aspects related to the processing of immiscible alloys, made possible by recent progress in both fields of moving boundary (VOF) methods and speed of computers, is discussed. It can capture in a single numerical treatment and without limiting assumptions both macroscopic information (i.e. the macrophysical problem, heretofore treated in terms of population dynamics) and microscopic details (i.e. the microphysical problem, heretofore treated within the framework of boundary integral methods and/or under the assumption of nondeformable drops). The role played by coalescence in changing the Marangoni More >

MARÍA ESTHER DIUPOTEX-CHONG¹, NÉSTOR J. CAZZANIGA², ALEJANDRA HERNÁNDEZ-SANTOYO³, JOSÉ MIGUEL BETANCOURT-RULE⁴

BIOCELL, Vol.28, No.3, pp. 279-285, 2004, DOI:10.32604/biocell.2004.28.279

Abstract Mitotic chromosomes of the freshwater snail Pomacea patula catemacensis (Baker 1922) were analyzed on gill tissue of specimens from the type locality (Lake Catemaco, Mexico). The diploid number of chromosomes is 2n = 26, including nine metacentric and four submetacentric pairs; therefore, the fundamental number is FN = 52. No sex chromosomes could be identified. The same chromosome number and morphology were already reported for P. flagellata, i.e., the other species of the genus living in Mexico. The basic haploid number for family Ampullariidae was reported to be n° =°14 in the literature; so, its reduction to More >

A. Rama Chandra Murthy¹, G.S. Palani¹, Nagesh R. Iyer¹

CMC-Computers, Materials & Continua, Vol.1, No.4, pp. 289-300, 2004, DOI:10.3970/cmc.2004.001.289

Abstract In this paper an improved Wheeler residual stress model has been proposed for remaining life assessment of cracked plate panels under variable amplitude loading (VAL). The improvement to the Wheeler residual stress model is in terms of the expressions for the shaping exponent, which is generally obtained through experiments. Simple expressions for the computation of shaping exponent have been proposed for compact tension (CT) specimen and plate panels with a center crack or an edge crack. The remaining life assessment has been carried out by employing linear elastic fracture mechanics (LEFM) principles. In the present… More >

R. Gangadharan¹, A. Rajagopal¹, S.M. Sivakumar^{1, 2}

CMC-Computers, Materials & Continua, Vol.1, No.3, pp. 229-244, 2004, DOI:10.3970/cmc.2004.001.229

Abstract A new r-h adaptive scheme is proposed and formulated. It involves a combination of the configurational force based r-adaption with weighted Laplacian smoothing and mesh enrichment by h-refinement. A Zienkiewicz-Zhu best guess stress error estimator is used in the h-refinement strategy. The best sequence for combining the effectiveness of r- and h- adaption has been evolved at in this study. A further reduction in the potential energy and the relative error norm of the system is found to be achieved with combined r-adaption and mesh enrichment (in the form h-refinement). Numerical study confirms that the More >