Morrell, R (1996) Traceability calibrating the 'Grindosonic', for impact excitation modulus measurement. NPL Report. CMMT(A)36

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Abstract

The "Grindosonic". is a commercial instrument designed for determining the fundamental natural frequency of a struck object. It is intended principally for quality assurance of products such as vitreous-bonded grinding wheels, but it can also be used for determining the elastic moduli of uniform geometry test-pieces of ceramics and other elastic materials. The instrument detects the fundamental natural frequency of a decaying signal after higher modes have been damped out. A means of providing traceable calibration for the instrument under such detection conditions has been devised. The frequency of a sinusoidal source is measured using a traceably calibrated frequency counter. This frequency is used to energise a hi-fi loudspeaker, and a manual volume control is used to provide a signal of the characteristics required to trigger the "Grindosonic" detection system, using either a microphone or a piezoelectric detector. A comparison of the frequencies recorded on both instruments provides a check on the accuracy of the "Grindosonic".

Item Type:	Report/Guide (NPL Report)
NPL Report No.:	CMMT(A)36
Subjects:	Advanced Materials
Last Modified:	02 Feb 2018 13:18
URI:	http://eprintspublications.npl.co.uk/id/eprint/553

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