Zeqiri, B; Hodnett, M (1997) Standardisation of procedures for ultrasonic inspection of polymer matrix composites: transducer characterisation and materials evaluation. NPL Report. CMAM 9

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Abstract

The work described within this report was undertaken in support of a three year DTI-Aerospace Division funded project entitled "Standardised procedures for ultrasonic inspection of polymer matrix composites". The report gives a detailed account of the research work undertaken by the Centre for Mechanical and Acoustical Metrology (CMAM) at NPL, providing technical support and input in a range of key areas. In the field of transducer evaluation, an extensive comparison of small pulse-echo target and hydrophone based characterisation measurements has been completed. The utilisation of CMAM's unique high spatial resolution, wide-bandwidth membrane hydrophones has, for the first time, demonstrated that the propagation of ultrasound generated by NDT transducers is a nonlinear process. The implications of the resultant waveform distortion for field characterisation measurements as well as for the absolute determination of material attenuation have been assessed. A preliIninary attempt to model the effect of nonlinear loss on C-scan attenuation measurements has been made, the results being compared with experiment. The report also describes a number of other studies carried out within the project to underpin several key technical areas. These include a systematic investigation of the effect of collimation on the transducer field as well as extensive measurements made to determine the ultrasonic properties (attenuation coefficient, phase velocity) of a range of materials important to the project.

Item Type:	Report/Guide (NPL Report)
NPL Report No.:	CMAM 9
Subjects:	Acoustics Acoustics > Ultrasound
Last Modified:	02 Feb 2018 13:18
URI:	https://eprintspublications.npl.co.uk/id/eprint/816