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 >

N.S.Mera¹, L. Elliott², D.B.Ingham²

CMES-Computer Modeling in Engineering & Sciences, Vol.15, No.2, pp. 107-114, 2006, DOI:10.3970/cmes.2006.015.107

Abstract The purpose of this study is to investigate the efficiency, accuracy and rate of convergence of an evolutionary algorithm for detecting inclusions parametrised by superellipses in non-destructive evaluation and testing. The inverse problem investigated consists of identifying the geometry of discontinuities in a conductive material from Cauchy data measurements taken on the boundary. Temperature and heat flux are measured on the outside boundary of the domain and the position and the size of a super-elliptical inclusion are determined by minimising an objective functional using an evolution strategy. The super-elliptical form allows the parametric model to More >

L.A. de Lacerda¹, J. M. da Silva¹

CMES-Computer Modeling in Engineering & Sciences, Vol.14, No.3, pp. 153-160, 2006, DOI:10.3970/cmes.2006.014.153

Abstract A two-dimensional boundary element formulation is presented and coupled to a genetic algorithm to identify polarization curves of buried slender structures. The dual boundary element method is implemented to model the cathodic protection of the metallic body and the genetic algorithm is employed to deal with the inverse problem of determining the non-linear polarization curve, which describes the relation between current density and electrochemical potential at the soil metal interface. In this work, this non-linear relation resulting from anodic and cathodic reactions is represented by a classical seven parameters expression. Stratified soil resistivity is modeled 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 >

M.H. Djavareshkian¹, M. Khalili²

FDMP-Fluid Dynamics & Materials Processing, Vol.2, No.4, pp. 299-308, 2006, DOI:10.3970/fdmp.2006.002.299

Abstract This paper opens a new horizon on the simulation of sloshing phenomena. One of the most popular Finite Volume methods called VOF (Volume Of Fluid) method is used for tracking the flow in containers. The algorithm is tested for different fluid elevations, physical conditions in different road curves and liquid properties. The method is then validated against an analytical and another numerical solution. These comparisons show that the VOF can effectively solve the sloshing problem for different fluids and a variety of physical and geometrical conditions. More >

G.S. Palani¹, Nagesh R. Iyer¹, B. Dattaguru²

Structural Durability & Health Monitoring, Vol.1, No.2, pp. 107-120, 2005, DOI:10.3970/sdhm.2005.001.107

Abstract A posteriori error estimation and adaptive refinement technique for 2-D/3-D crack problems is the state-of-the-art. In this paper a new a posteriori error estimator based on strain energy release rate (SERR) or stress intensity factor (SIF) at the crack tip region has been proposed and used along with the stress based error estimator for reliable fracture analysis of 2-D crack problems. The proposed a posteriori error estimator is called the K-S error estimator. Further, h-adaptive mesh refinement strategy which can be used with K-S error estimator has been proposed for fracture analysis of 2-D crack problems. The performance 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 >

Christopher A. Lemmon^1,2, Nathan J. Sniadecki³, Sami Alom Ruiz^1,3, John L. Tan, Lewis H. Romer^2,4,5, Christopher S. Chen^3,4

Molecular & Cellular Biomechanics, Vol.2, No.1, pp. 1-16, 2005, DOI:10.3970/mcb.2005.002.001

Abstract The interplay of mechanical forces between the extracellular environment and the cytoskeleton drives development, repair, and senescence in many tissues. Quantitative definition of these forces is a vital step in understanding cellular mechanosensing. Microfabricated post array detectors (mPADs) provide direct measurements of cell-generated forces during cell adhesion to extracellular matrix. A new approach to mPAD post labeling, volumetric imaging, and an analysis of post bending mechanics determined that cells apply shear forces and not point moments at the matrix interface. In addition, these forces could be accurately resolved from post deflections by using images of More >

Jin Yeon Cho¹, Jae Mo An², You Me Song¹, Seungsoo Lee¹, Dong Whan Choi¹

CMES-Computer Modeling in Engineering & Sciences, Vol.9, No.1, pp. 1-18, 2005, DOI:10.3970/cmes.2005.009.001

Abstract A displacement welding technique is proposed to carry out coupled analysis of the integrated whole model which consists of independently modeled finite element substructures. In the proposed method, the incompatible displacement fields in the interfaces of independently modeled substructures are directly welded together through a blended function that is newly defined in the transient region of mismatching interface. To construct the blended function, the moving least squares function, which does not require well-defined nodal connectivity, is utilized along with the original finite element shape function. The meshless character of the moving least squares function makes More >

B. Pluymers¹, W. Desmet¹, D. Vandepitte¹, P. Sas¹

CMES-Computer Modeling in Engineering & Sciences, Vol.7, No.2, pp. 173-184, 2005, DOI:10.3970/cmes.2005.007.173

Abstract Conventional element based methods for modelling structural-acoustic radiation problems are limited to low-frequency applications. Recently, a novel prediction technique has been developed based on the indirect Trefftz approach. This new wave based method is computationally more efficient than the element based methods and, as a consequence, can tackle problems also at higher frequencies. This paper discusses the basic principles of the new method and illustrates its performance for the two-dimensional radiation analysis of a bass-reflex loudspeaker. More >