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 >

Jean-Jacques Sinou¹

Structural Durability & Health Monitoring, Vol.3, No.3, pp. 133-164, 2007, DOI:10.3970/sdhm.2007.003.133

Abstract This paper aims to establish a damage identification methodology, called the Frequencies' Ratio Surfaces Intersection method (FRSI-method), for predicting not only the location and depth of the crack but also the crack orientation in a circular cross section beam. Two new criterions %Δ_i^cracked and %ψ_i,j^cracked that consider only the ratio of the natural frequencies of the cracked beam are introduced and discussed in order to detect the crack parameters. In order to avoid worse diagnostic, it is demonstrated that a robust identification of crack location is possible by investigating the emergence of extra antiresonance peaks… More >

J. Mohan¹, D. Carolan¹, N. Murphy¹, A. Ivankovic¹, D. Dowling¹

Structural Durability & Health Monitoring, Vol.3, No.2, pp. 81-86, 2007, DOI:10.3970/sdhm.2007.003.081

Abstract The aim of this work is to investigate the influence of a variety of plasma treatments on the surface properties of an epoxy-based composite material and to establish a relationship between these properties and the subsequent mechanical behaviour of adhesively bonded joints. To this end, specimens were subjected to three different types of plasma treatment: two short treatments (2min) of He and He plus O₂, and one long treatment (15min) of He plus O₂. The variation in surface energy of the composite specimens was examined in each case over a period of up to 3 days… More >

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. Kumosa¹

Structural Durability & Health Monitoring, Vol.3, No.1, pp. 35-50, 2007, DOI:10.3970/sdhm.2007.003.035

Abstract This paper deals with the structural integrity and durability of suspension composite (non-ceramic, polymer) insulators widely used in power transmission systems around the world. Under certain conditions, the insulators can fail in-service both electrically and mechanically resulting in the drop of energized transmission lines and power outages. In this work, predominantly mechanical failures of the insulators are discussed. In particular, the most important characteristics of a catastrophic failure process called brittle fracture are described. Subsequently, two examples of insulator failures by brittle fracture are shown and their causes explained. Finally, several recommendations on how to 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 >

M.T. MARTIN^*, H.E. PEDRANZANI^**, R. SIERRA DE GRADO

BIOCELL, Vol.31, No.1, pp. 41-49, 2007, DOI:10.32604/biocell.2007.31.041

Abstract An in vitro collection has been established with selected European aspen from Palencia province (Spain). Currently, this collection includes 32 high quality clones, selected for their good bearing and healthy state. Most of them belong to different discrete local populations.
Populus tremula L. was propagated in proliferation Aspen Culture Medium; they required subculture every 3 months. The purpose of this study was, therefore, to select a medium which allows the maintenance of 32 clones for a period longer than 3 months without subculture and to observe the behavior of those clones in 15 different culture medium compositions. Seven… More >

B. Gatmiri¹

The International Conference on Computational & Experimental Engineering and Sciences, Vol.4, No.3, pp. 159-166, 2007, DOI:10.3970/icces.2007.004.159

Abstract This document summarizes the basic concepts and steps of establishment of the set of equations of wave propoagation in far field and of the dynamic behaviour of porous media in the near field. A breif description of HYBRID software as a powerful tool for evaluation of local seismic site effect is presented. The Combination of the FEM and BEM and improvement of numerical algorithm for the time truncation are described. More >

S. Okamoto¹, H. Noguchi²

The International Conference on Computational & Experimental Engineering and Sciences, Vol.2, No.4, pp. 131-136, 2007, DOI:10.3970/icces.2007.002.131

Abstract This paper presents a control of walking robot by using inverse dynamics of link mechanisms, which has already been proposed and applied in several in-plane motions. In this method, FEM is used for the discretization of equations of motion. This method calculates nodal forces by evaluating equations of motion in a matrix form, and thus information from the entire system can be handled efficiently, and the torques input to each joint of link mechanisms to achieve required motion are calculated easily. This method is suitable to the feed-forward control of closed-loop or continuously link mechanisms. More >

Christine M. Scotti¹, Sergio L. Cornejo², Ender A. Finol³

The International Conference on Computational & Experimental Engineering and Sciences, Vol.1, No.1, pp. 41-48, 2007, DOI:10.3970/icces.2007.001.041

Abstract Abdominal aortic aneurysm (AAA) rupture is believed to represent the culmination of a complex vascular mechanism partially driven by the forces exerted on the arterial wall. In the present investigation, we present fully coupled fluid-structure interaction (FSI) and finite element analysis (FEA) computations of a patient-specific AAA model. This work advances previous FSI AAA modeling by including localized intraluminal thrombus and the comparison of FSI- and FEA-predicted wall stress distributions. The FSI transient fluid and wall dynamics resulted in a maximum wall stress 21% higher than that obtained with FEA, demonstrating the importance of modeling More >