Abdulnaser M. Alshoaibi^1,2, M. S. A. Hadi², A. K. Ariffin²

Structural Durability & Health Monitoring, Vol.3, No.1, pp. 15-28, 2007, DOI:10.3970/sdhm.2007.003.015

Abstract An adaptive finite element method is employed to analyze two-dimensional linear elastic fracture problems. The mesh is generated by the advancing front method and the norm stress error is taken as a posteriori error estimator for the h-type adaptive refinement. The stress intensity factors are estimated by a displacement extrapolation technique. The near crack tip displacements used are obtained from specific nodes of natural six-noded quarter-point elements which are generated around the crack tip defined by the user. The crack growth and its direction are determined by the calculated stress intensity factors as the maximum circumference 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 >

C.P. Providakis¹

Structural Durability & Health Monitoring, Vol.2, No.4, pp. 249-254, 2006, DOI:10.3970/sdhm.2006.002.249

Abstract This paper explores the concept of strain energy density rate in relation to the crack initiation in fracture analysis problems arising in creeping cracked structural components. The analysis of the components is performed by using the boundary element methodology in association with the employment of singular boundary elements for the modeling of the crack tip region. The deformation of the material is assumed to be described by an elastic power law creep model. The strain energy density rate theory is applied to determine the direction of the crack initiation for a center cracked plate in More >

J. Toribio ¹

Structural Durability & Health Monitoring, Vol.2, No.4, pp. 239-248, 2006, DOI:10.3970/sdhm.2006.002.239

Abstract This paper reviews the fracture performance in air and aggressive environment (stress corrosion cracking) of eutectoid prestressing steel wires with different levels of cold drawing. In air environment, a micromechanical model of fracture is proposed to rationalize the results on the basis of the microstructure of the steels after drawing and the model of Miller & Smith of fracture of pearlitic microstructure by shear cracking of the cementite lamellae. In hydrogen assisted cracking (HAC), a microstructure-based model is proposed on the basis of the Miller & Smith model and the mechanism of hydrogen enhanced decohesion or, more More >

P.D. Shah¹, Ch. Song², C.L. Tan¹, X. Wang¹

Structural Durability & Health Monitoring, Vol.2, No.4, pp. 225-238, 2006, DOI:10.3970/sdhm.2006.002.225

Abstract Numerical T-stress solutions in two dimensional anisotropic cracked bodies are very scarce in the literature. Schemes to evaluate this fracture parameter in anisotropy have been reported only fairly recently. Among them are those developed in conjunction with two different computational techniques, namely, the Boundary Element Method (BEM) and the Scaled Boundary Finite-Element Method (SBFEM). This paper provides a review of the respective schemes using these techniques and demonstrates their efficacy with three examples. These examples, which are of engineering importance, involve cracks lying in a homogeneous medium as well as at the interface between dissimilar media. More >

E.J. Sapountzakis¹, V.G. Mokos¹

Structural Durability & Health Monitoring, Vol.2, No.4, pp. 207-224, 2006, DOI:10.3970/sdhm.2006.002.207

Abstract In this paper a boundary element method is developed for the second-order analysis of frames consisting of composite beams of arbitrary constant cross section, taking into account shear deformation effect. The composite beam consists of materials in contact, each of which can surround a finite number of inclusions. The materials have different elasticity and shear moduli with same Poisson's ratio and are firmly bonded together. Each beam is subjected in an arbitrarily concentrated or distributed variable axial loading, while the shear loading is applied at the shear center of the cross section, avoiding in this… More >

H. Hadavinia¹, K. Gordnian¹, J. Karwatzki¹, A. Aboutorabi¹

Structural Durability & Health Monitoring, Vol.2, No.4, pp. 197-206, 2006, DOI:10.3970/sdhm.2006.002.197

Abstract The cylindrical bending of thick laminated sandwich plates under static loading is studied based on the first order shear deformation theory (FSDT). FSDT generally requires a shear correction factor (SCF) to account for the deflection owing to the transverse shear. In this paper the SCF is derived using energy equivalence method. It is shown that depending on the mechanical and geometrical properties of the layers, the contribution of the transverse shear stress to the maximum deflection of the plate is variable and in some cases account for up to around 88% of the total deflection. More >

R. Citarella¹, A. Apicella²

Structural Durability & Health Monitoring, Vol.2, No.3, pp. 183-196, 2006, DOI:10.3970/sdhm.2006.002.183

Abstract This paper presents an overview of the achievements of a research and development project sponsored by the European Commission in the general area of Key Actions and New Perspectives in Aeronautics. The project was coordinated by Alenia and involved partners from major European Aircraft and Helicopter manufactures as well as research institutions and universities. The project was in support of EU policies on energy and environment, in addition to those on transport, economic and social cohesion, industry and, of course, research and technology.
The overall objective of Advanced Design concepts and Maintenance by Integrated risk Evaluation… More >

G. Davì¹, A. Milazzo¹

Structural Durability & Health Monitoring, Vol.2, No.3, pp. 177-182, 2006, DOI:10.3970/sdhm.2006.002.177

Abstract An alternative single domain boundary element formulation and its numerical implementation are presented for the analysis of two-dimensional cracked bodies. The problem is formulated employing the classical displacement boundary integral representation and a novel integral equation based on the stress or Airy's function. This integral equation written on the crack provides the relations needed to determine the problem solution in the framework of linear elastic fracture mechanics. Results are presented for typical problems in terms of stress intensity factors and they show the accuracy and efficiency of the approach. More >

V. Mallardo, C. Alessandri¹

Structural Durability & Health Monitoring, Vol.2, No.3, pp. 165-176, 2006, DOI:10.3970/sdhm.2006.002.165

Abstract The formation of cracks and their propagation in brittle materials has been intensively studied in the last years. The main difficulty is related to the theoretical and numerical possibility to follow the development of regions of highly localised strains. The nonlinear phenomenon is physically different from the one which occurs in ductile materials: it starts with a narrow fracture process zone containing a large number of distributed microcracks which could lead to the formation of macrocracks and eventually to rupture. In the present paper, a simple nonlocal damage model is coupled to the crack analysis More >