C. Colombo¹, M. Guagliano^1,2, L. Vergani¹

Structural Durability & Health Monitoring, Vol.4, No.2, pp. 67-76, 2008, DOI:10.3970/sdhm.2008.004.067

Abstract With the aim of experimentally assessing the stress intensity factors under mixed-mode loading along a crack front, the case of an internal elliptical crack is analyzed. An experimental test is performed on a three-dimensional photoelastic model made in epoxy resin. This model contains an inner natural crack, created by thermal shock. The crack is inclined in the cylindrical model, loaded with a tensile stress field.
Exploiting the characteristics of the epoxy resin, and using the stress freezing technique, it is possible to keep memory of the stresses near to the crack tip, once the specimen is unloaded. More >

A. Brasiliano¹, W.R. Souza², G.N. Doz³, J.L.V. Brito⁴

Structural Durability & Health Monitoring, Vol.4, No.2, pp. 53-66, 2008, DOI:10.3970/sdhm.2008.004.053

Abstract It can be observed that usually, during structures useful life they are submitted to deterioration processes that, depending on the intensity, may affect their performance and load capacity and, as a result, their safety. In this case, it is necessary to accomplish an inspection in order to evaluate the conditions of the structure and to locate and quantify the intensity of the damage. Another important point is to study the behavior of brittle material beams with cracks, as an attempt of understanding the rupture mechanism and crack propagation phenomenon. In this paper, the Residual Error More >

F.R. Biglari¹, A. Agahi¹, O. Nikfarjam², B. M. Dariani¹, K. Nikbin³

Structural Durability & Health Monitoring, Vol.4, No.1, pp. 47-52, 2008, DOI:10.3970/sdhm.2008.004.047

Abstract A modified sensitivity analysis has been applied to an elastic-plastic finite element analysis 3D blank design in sheet metal forming. In recent literature, the sensitivity method has successfully been applied to several arbitrary shapes. However, in the present paper the sensitivity coefficients are not considered constant during the analysis. The presented approach computes the new coefficients from the two last iterations. This method can produce an initial blank boundary shape that has any arbitrary flange shape. A cup with uniform flange has been studied in detail and results show a faster solution convergence than the More >

H. Ghasemnejad¹, H. Hadavinia^1,2, D. Marchant¹, A. Aboutorabi¹

Structural Durability & Health Monitoring, Vol.4, No.1, pp. 29-46, 2008, DOI:10.3970/sdhm.2008.004.029

Abstract In this paper the crashworthiness capabilities of thin-walled corrugated crash boxes in axial crushing relative to flat sidewall boxes from the same material are investigated. In order to achieve this, various design of corrugated aluminium alloy 6060 temper T4 crash boxes were chosen and their axial crushing behaviour under impact loading was studied by developing a theoretical model based on Super Folding Element theory and by conducting finite element analysis using LS-DYNA in ANSYS. From the theoretical and FE analysis the crush force efficiency, the specific energy absorption and the frequency and amplitude of fluctuation of More >

F. R. M. Romlay¹

Structural Durability & Health Monitoring, Vol.4, No.1, pp. 19-28, 2008, DOI:10.3970/sdhm.2008.004.019

Abstract This paper presents a surface contact static stress of a spur gear system combined with dynamic characteristic using transient Finite Element Method (FEM). Traditionally, the static stress analysis is done separately with dynamic properties due to limitation of complex equation and avoiding of error occurred. However, in this paper, static stress information is combined with the dynamic mechanism due to the time consuming during the design and analysis stage. A transient FEM analysis is carried out to formulate and solve large systems of algebraic equations in order to obtain a relationship between the contact parameter… More >

L. Susmel^1,2, D. Taylor², R. Tovo¹

Structural Durability & Health Monitoring, Vol.4, No.1, pp. 1-18, 2008, DOI:10.3970/sdhm.2008.004.001

Abstract This paper investigates some theoretical aspects related to the use of the Theory of Critical Distances (TCD) when employed to estimate notch fatigue limits. The linear-elastic TCD takes as a starting point the hypothesis that notched components are in their fatigue limit condition when an effective stress, whose value depends on a characteristic length, equals the material plain fatigue limit. Such an idea can be formalised by following different strategies: either assuming that the effective stress depends only on the profile of the stress field damaging the fatigue process zone and the reference distance is… More >

Aleš Belšak¹, Jurij Prezelj²

Structural Durability & Health Monitoring, Vol.3, No.4, pp. 239-246, 2007, DOI:10.3970/sdhm.2007.003.239

Abstract Noise source vizualization represents an important tool in the field of technical acoustics. There are many different techniques of noise source visualization. Most of them, however, are intended for a specific noise source in a specific type of acoustic environment. Consequently, a certain visualization method can be used only for certain types of noise sources in a specific acoustic environment and in a restricted frequency area. This paper presents a new visualization method of complex noise sources on the basis of the use of an acoustic camera. A new algorithm has been used, which makes More >

G. Davì¹, A. Milazzo¹

Structural Durability & Health Monitoring, Vol.3, No.4, pp. 229-238, 2007, DOI:10.3970/sdhm.2007.003.229

Abstract An original and alternative single domain boundary element formulation and its numerical implementation are presented for the analysis of orthotropic two-dimensional cracked bodies. The problem is formulated employing the classical displacement boundary integral representation and an alternative integral equation deduced on the basis of the stress function theory. This integral equation written on the crack provides the relations needed to determine the problem solution in the framework of linear elastic fracture mechanics. Numerical examples are reported and discussed to demonstrate the accuracy of the proposed approach. More >

C.P. Providakis¹, M.E. Voutetaki

Structural Durability & Health Monitoring, Vol.3, No.4, pp. 211-228, 2007, DOI:10.3970/sdhm.2007.003.211

Abstract Piezoceramic transducers have emerged as new tools for the health monitoring of large-scale structures due to their advantages of active sensing, low cost, quick response, availability in different shapes, and simplicity for implementations. In the present paper, a statistical metamodeling utilization of electro-mechanical (E/M) admittance approach by applying piezoelectric materials to the damage identification is investigated. A response surface metamodel is constructed by empirically fitting a model to a set of design points chosen using a Box-Behnken design of experiment (simulation) technique. This empirical fit allows polynomial models to be produced for relating damage parameter More >

M. M. Rahman¹, A. K. Ariffin², S. Abdullah², A. B. Rosli¹

Structural Durability & Health Monitoring, Vol.3, No.4, pp. 197-210, 2007, DOI:10.3970/sdhm.2007.003.197

Abstract Low weight and long lifetime are necessary requirements for automobiles to significantly reduce CO₂ emission and environmental burdens in their use. Aluminum alloys are one of the most promising materials selections for automobiles parts and electrical components to reduce their weight and to increase their specific strength. This paper presents the role of nitriding on the fatigue life of the vibrating cylinder block for a new two-stroke free piston engine using variable amplitude loading conditions. The finite element modeling and analysis have been performed utilising a computer aided design and a finite element analysis codes respectively.… More >