Development of ultrasonic guided wave techniques for examination of non-cylindrical components

AbstractIn the past ten years ultrasonic guided wave systems have become widely used for the rapid large-scale examination of pipes and pipelines in pressure containing systems, for the detection of corrosion and other degradation in service. As a result, the characteristics of the guided wave modes existing in pipes have been studied extensively and are well understood. Advantage is taken of the fact that a pipe is essentially a one-dimensional object and that guided waves travelling along it will return to the sensor location for detection. Guided waves may also be applied to other components which are non-cylindrical, either those of constant cross-section such as railway rails or structural I beams, or constructions consisting of plates. However, in both cases the guided wave systems are more complex than in simple cylinders and successful application of this technique for large scale examination of these constructions requires further development of the understanding of the properties of the waves propagating and regularities of their generation. This paper describes work carried out under the EU-funded LRUCM project to develop techniques for detection of corrosion and cracking in railway rails and structural sheet piles used to retain earth embankments, river banks etc. The work described involved identification of wave modes present, derivation of dispersion curves to describe propagation behaviour and evaluation of experimental data to explain mode conversions and interactions with interfaces observed in the results

Investigation of the Acoustic Properties of Viscosity Standards

Longitudinal and shear ultrasonic wave velocities were measured versus temperature in the viscosity standards of Paragon S8000S, N30000S and Cannon N2700000. The measurements were performed by the through-transmission method at the frequency of 2 MHz. Ultrasonic pulses were sent via polymethyl methacrylate (PMMA) waveguides between the tips of which a small amount of the particular standard liquid was placed. The velocities of longitudinal and shear waves were determined to depend on the viscosity of the liquid and increase with the viscosity

Interaction of the A0 lamb wave mode with a de-lamination type defect in GLARE3-3/2 composite material

Ultrasonic non-destructive testing and evaluation is one of the most common methods applied for inspection of composite materials. The measured wave velocity gives information about composite properties. Changes in the ultrasonic wave velocity or in the amplitude of the ultrasonic signal indicate possible defects. The application of a single-side access air-coupled ultrasonic technique for the investigation of the Lamb wave propagation in the composite material, and numerical simulations of the Lamb wave interaction with the de-lamination type defect, are presented here. The interaction between wave and damage is analysed in detail. The change of the Lamb wave velocity was measured in a de-laminated area of the composite material GLARE3-3/2. The influence of the de-lamination on the Lamb wave propagation velocity is investigated experimentally and numerically

Fizinio krūvio ir maisto papildų įtaka imuninės sistemos rodikliams

Vytauto Didžiojo universitetasŠvietimo akademij

Investigation of Mode Conversion in Ultrasonic Air-coupled Non-destructive Testing

The paper deals with development and investigation of air-coupled ultrasonic techniques for inspection of components of modern aircrafts such as carbon/glass fibre reinforced plastics, fibre metal laminates (GLARE) and honeycombs. In the work interaction of ultrasonic waves with delamination type defect and mode conversions were investigated. The mode conversions were investigated in the case of two different techniques - the through-transmission technique and single-side access technique with exploitation of Lamb waves. It was demonstrated that in the case of the trough-transmission technique and application of focused transducers the additional Lamb waves are generated, which causes leaky waves in air affecting B and C-scan images of defect

Physical load and physical functional capacity features in Greek-Roman wrestlers over the Olympic cycle

Vytauto Didžiojo universitetasŠvietimo akademij

Investigation of Interaction of the Lamb Wave with Delamination Type Defect in GLARE Composite Using Air-coupled Ultrasonic Technique

Ultrasonic NDT is one of the most frequently applied methods for testing of composite materials. A measured wave velocity gives information about composite properties. A change in the velocity indicates possible presence of a defect. Application possibilities of air-coupled ultrasonic technique for investigation of the Lamb wave propagation in the composite material and the numerical simulations of the Lamb wave interaction with the delamination type defect are presented. The Lamb wave velocities are measured in delaminated and defect-free areas of the composite material GLARE. The delamination position influence on the Lamb wave propagation velocity is investigated experimentally and numerically

Non-destructive Testing of Fuel Tanks Using Long-range Ultrasonics

The new ultrasonic technique based on application of long range guided waves is proposed for detection of the defects in a storage tank floor. The technique needs access only to the outer edge of the tank floor and do not require emptying and cleaning of the tank. The propagation of the guided waves in the tank floor has been carried out using simulation and experimental verification. The results obtained on the reduced size tank and results of in situ experiments are presented

Interaction of the A0 lamb wave mode with a de-lamination type defect in GLARE3-3/2 composite material

Ultrasonic non-destructive testing and evaluation is one of the most common methods applied for inspection of composite materials. The measured wave velocity gives information about composite properties. Changes in the ultrasonic wave velocity or in the amplitude of the ultrasonic signal indicate possible defects. The application of a single-side access air-coupled ultrasonic technique for the investigation of the Lamb wave propagation in the composite material, and numerical simulations of the Lamb wave interaction with the de-lamination type defect, are presented here. The interaction between wave and damage is analysed in detail. The change of the Lamb wave velocity was measured in a de-laminated area of the composite material GLARE3-3/2. The influence of the de-lamination on the Lamb wave propagation velocity is investigated experimentally and numerically