Quantitative non-destructive testing

The work undertaken during this period included two primary efforts. The first is a continuation of theoretical development from the previous year of models and data analyses for NDE using the Optical Thermal Infra-Red Measurement System (OPTITHIRMS) system, which involves heat injection with a laser and observation of the resulting thermal pattern with an infrared imaging system. The second is an investigation into the use of the thermoelastic effect as an effective tool for NDE. As in the past, the effort is aimed towards NDE techniques applicable to composite materials in structural applications. The theoretical development described produced several models of temperature patterns over several geometries and material types. Agreement between model data and temperature observations was obtained. A model study with one of these models investigated some fundamental difficulties with the proposed method (the primitive equation method) for obtaining diffusivity values in plates of thickness and supplied guidelines for avoiding these difficulties. A wide range of computing speeds was found among the various models, with a one-dimensional model based on Laplace's integral solution being both very fast and very accurate

Shape-based defect classification for Non Destructive Testing

The aim of this work is to classify the aerospace structure defects detected by eddy current non-destructive testing. The proposed method is based on the assumption that the defect is bound to the reaction of the probe coil impedance during the test. Impedance plane analysis is used to extract a feature vector from the shape of the coil impedance in the complex plane, through the use of some geometric parameters. Shape recognition is tested with three different machine-learning based classifiers: decision trees, neural networks and Naive Bayes. The performance of the proposed detection system are measured in terms of accuracy, sensitivity, specificity, precision and Matthews correlation coefficient. Several experiments are performed on dataset of eddy current signal samples for aircraft structures. The obtained results demonstrate the usefulness of our approach and the competiveness against existing descriptors.Comment: 5 pages, IEEE International Worksho

Non-destructive Testing of Pipelines

This paper shall present different, contemporarily available non-destructive testing (NDT) methods of pipelines and compare them to each other from the technical and economical point of view. An evaluation of their suitability for CERN activities, based on the opinions and experience of various specialists at CERN (LHC, ST, TIS), is also introduced

Non-destructive testing of composite plates by holographic vibrometry

We report on a wide-field optical monitoring method for revealing local delaminations in sandwich-type composite plates at video-rate by holographic vibrometry. Non-contact measurements of low frequency flexural waves is performed with time-averaged heterodyne holography. It enables narrowband imaging of local out-of-plane nanometric vibration amplitudes under sinusoidal excitation, and reveals delamination defects, which cause local resonances of flexural waves. The size of the defect can be estimated from the first resonance frequency of the flexural wave and the mechanical parameters of the observed layer of the composite plate

Hybrid holographic non-destructive test system

An automatic hybrid holographic non-destructive testing (HNDT) method and system capable of detecting flaws or debonds contained within certain materials are described. This system incorporates the techniques of optical holography, acoustical/optical holography and holographic correlation in determining the structural integrity of a test object. An automatic processing system including a detector and automatic data processor is used in conjunction with the three holographic techniques for correlating and interpreting the information supplied by the non-destructive systems. The automatic system also includes a sensor which directly translates an optical data format produced by the holographic techniques into electrical signals and then transmits this information to a digital computer for indicating the structural properties of the test object. The computer interprets the data gathered and determines whether further testing is necessary as well as the format of this new testing procedure

Distributed Computing In Non-Destructive Testing

This article contains an overview of modern trends in the data processing information technologies development, and propositions for using them to solve problems of non-destructive testing. The article describes some types of distributed computing. Particular attention is paid to grid technologies and cloud computing, and to their use for data processing in non-destructive testing

COST Action G8 : Non-destructive Analysis and Testing of Museum Objects

COST Action G8 (2000-2004) aims at creating a Europe- wide network that would enable co-operation and interaction between two groups of professionals: people directly concerned with the maintenance of our cultural heritage – conservators, curators, art historians, archaeologists – and analytical scientists, including chemists, physicists, geologists, metallurgists, mineralogists and microbiologists. The main objective of the action is to improve preservation and conservation of our cultural heritage by increasing knowledge of museum objects through non-destructive analysis and testing. The scientific activities of COST G8 include organising short-term scientific missions to train scientists of both groups in the other's field as well as to transfer practical experience among the European countries. Regular meetings in the form of workshops are organised in order to exchange the obtained knowledge in a broader group, and six working groups are active, which allows close collaboration in a specific field