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 >

D. Benasciutti¹, R. Tovo¹

Structural Durability & Health Monitoring, Vol.2, No.3, pp. 149-164, 2006, DOI:10.3970/sdhm.2006.002.149

Abstract The probability density functions used to characterize the distribution of fatigue cycles in random loads are usually defined over an infinite domain. This means that they give a non-zero probability to count cycles with an infinitely large peak or valley, which however seems of less physical sense. Moreover, practically all the methods existing in the literature completely neglect the negative effect on fatigue strength produced by fatigue cycles with positive mean values. With theses premises, this work tries to further extending the probabilistic theory used by the frequency-domain methods by addressing to distinct problems. First,… 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 >

L. Palermo Jr.¹, L.P.C.P.F. Almeida², P.C. Gonçalves³

Structural Durability & Health Monitoring, Vol.2, No.2, pp. 123-130, 2006, DOI:10.3970/sdhm.2006.002.123

Abstract The kernels of integrands are usually differentiated to obtain the general boundary integral equation (BIE) for stresses and its corresponding traction equation. An alternative BIE for stresses can be obtained when the tangential differential operator is introduced in problems using Kelvin type fundamental solutions. The order of the singularity is reduced with this strategy and the Cauchy principal value sense or the first order regularization can be used in the resultant BIE. The dual boundary element formulation with the BIE for tractions using the tangential differential operator is analyzed in the present study. Shape functions More >

P. Bocchini, C. Gentilini, F. Ubertini, E. Viola¹

Structural Durability & Health Monitoring, Vol.2, No.2, pp. 109-122, 2006, DOI:10.3970/sdhm.2006.002.109

Abstract This paper provides a simple and reliable method for the probabilistic characterization of the linear elastic response of frame structures with edge cracks of uncertain depth and location. A statistical analysis of the structural response allows consideration of the reliability of the investigated structure. A numerical example provides an indication of the performance of the approach proposed. More >

L. Susmel^1,2, D. Taylor²

Structural Durability & Health Monitoring, Vol.2, No.2, pp. 91-108, 2006, DOI:10.3970/sdhm.2006.002.091

Abstract This paper reports on an attempt to systematically re-interpret the conventional multiaxial fatigue criteria in terms of the Theory of Critical Distances: in the present study the criteria proposed by Crossland, Dang Van, Papadopoulos, Matake, McDiarmid, respectively, and the so-called Modified W\"{o}hler Curve Method were considered. The procedure devised to re-interpret the above methods in terms of the Theory of Critical Distances was based on the following two assumptions: (i) the critical distance is a material constant to be determined under fully-reversed uniaxial fatigue loading; (ii) the presence of non-zero mean stresses as well as… More >

L. Nobile¹, C. Carloni¹

Structural Durability & Health Monitoring, Vol.2, No.2, pp. 83-90, 2006, DOI:10.3970/sdhm.2006.002.083

Abstract The analysis of buckling of elastic columns is one of the first problem in structural engineering that was historically solved. Critical loads of perfect columns with various end restrains have been derived. Nevertheless, the perfect column is an idealized model. In reality, unavoidable imperfections should be considered. Solutions for transversal disturbing load, crookedness or load eccentricity have been proposed. Another frequent imperfection to be taken into account is the weakness at an interior location due to a partial edge crack. In this paper the influence of this type of imperfection on the critical load is More >