RAAI Project: Life-prediction and prognostics for railway axles under corrosion-fatigue damage

Corrbosion damage induced by atmospheric agents has been shown to be able to trigger fatigue failures of railway axles. In this tphaepenIreDwMetEofiCorl,sDrtleyelpideasirstocmnuesnast nocefowMnseaoculhitadonamitceadtlerEdensgucilnatensenirneinrmga,boIldnesetltilotiunetogffiStchuipeengrtirloyrwaTtnéhcanolyifcsode,aoUmpnatigvcearlusimnddaeedaresucdoreerLmroisesbniotasn,-oAffavt.tihRgeouvceiosacrnroodPdiaetsids,da1ex,tle1ec0ts4iu9or-nf0a.0c1eLainsbdoa, paper we firstly discuss consolidated results in modelling the growth of damage under corrosion-fatigue and its detection. Portugal craTchkisgrioswththebsiamckuglartoiuondtofolrtduensecdribthinrogutghhefduelvl-eslcoaplmemenetaosfuraemneewntpsrofganxolseticotrorolsiwonit-hfiantitghueeRdAamAaIgEeU.-fundedproject.Indetails, This is the background for describing the development of a new prognostic tool within the RAAI EU-funded project. In details, cCeFEMA, Department of Mechanical Engineering, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1, 1049-001 Lisboa, the new tool relies on a new automated scanner able to efficiently analyse optical measurements of the corroded axle surface and a the new tool relies on a new automated scanner able to efficientlPyoartnuaglaylse optical measurements of the corroded axle surface and an axle corrosion-fatigue mode

Design of a pulsed eddy current sensor for detection of defects in aircraft lap-joints

This paper presents a new type of pulsed eddy current (PEC) sensor that has been designed for defect detection in aircraft lap-joint structures. The sensor employs a new excitation circuit that requires no additional signal amplification and the paper also reports compensation techniques that improve the sensing resolution and stability. A new hybrid feature of the peak value in time domain and the maximum frequency magnitude in frequency domain has been investigated. A test rig has been built and some results from aircraft samples are presented

Wavelet-based PCA defect classification for pulsed eddy current NDT

A new approach for defect classification and quantification by using pulsed eddy current sensors and integration of principal component analysis and wavelet transform for feature based signal interpretation is presented. After reviewing the limitation of current parameters of peak value and its arrival time from pulsed eddy current signals, a two-step framework for defect classification and quantification is proposed by using adopted features from principal component analysis and wavelet analysis. For defect classification and quantification, different features have been extracted from the pulsed eddy current signals. Experimental tests have been undertaken for ferrous and non-ferrous metal samples with manufactured defects. The results have illustrated the new approach has better performance than the current approaches for surface and sub-surface defect classification. The defect quantification performance, which is difficult by using current approaches, is impressive

Multiple sensors on pulsed eddy-current detection for 3-D subsurface crack assessment

This paper proposes the use of multiple sensors in pulsed eddy-current detection for three-dimensional (3-D) subsurface flaw imaging. A normalization technique has been proposed to eliminate the characteristic variation among the Hall devices used in the probe and lift off effects. A principal component analysis-based feature extraction that provides orthogonal information for multiple sensor fusion has been introduced and investigated. Using the features of multiple projection coefficients, 3-D surface flaws can be measured and reconstructed. The experimental tests have illustrated that the proposed method has delivered more defect information than the conventional peak value and time for pulsed eddy-current sensors

Pulsed eddy current system for dynamic inspection of defects

Pulsed Eddy Current (PEC) techniques have been investigated and applied for field applications. On-line inspection is essential for many manufacturing processes and other NDE applications. This paper investigates the dynamic behaviour of pulsed eddy current techniques and the feasibility of their use in an on-line inspection system. After discussing the PEC principles and their signal signatures, an approach on improving the dynamic response of PEC is introduced and tested. The results have illustrated that the proposed PEC system and their feature extraction can be used for real-time inspection such as NDT for manufacturing processe

Tomorrow A peaceful path to urban reform: the feasibility of accommodating 75% of new homes in urban areas

SIGLEAvailable from British Library Document Supply Centre-DSC:98/23761 / BLDSC - British Library Document Supply CentreGBUnited Kingdo