03:03 May-23-2002 Re: Thickness measurement of GFRP : : Can anyone suggest a quick (and preferably cheap) method of measuring the thickness of GFRP in the range of 5 to 25mm? We have conventional UT equipment, with a few low frequency probes(1MHz). . : Thanks in advance . : Ishbel Macdonald
Ultrasonic through thickness measurements using low frequency compession works well. There are problems where the density or the fibre wetting by the epoxy is low and the backwall echo falls off and therefore a comparative inspection should be carried out, comparing adjacent areas.
Additionaly magnetic methods can be used. This employs the use of a target such as a ball bearing or small bar magnet on the inside of the tank or hull and measure the effective fall off or increase in the magnetic field as the thickness increases or decreases.
05:34 May-23-2002 Re: Thickness measurement of GFRP : Can anyone suggest a quick (and preferably cheap) method of measuring the thickness of GFRP in the range of 5 to 25mm? We have conventional UT equipment, with a few low frequency probes(1MHz).
It is usually possible to ultrasonically measure thickness of GFRP in the indicated range in a pulse/echo mode using the right sort of equipment -- a thickness gage or flaw detector with optimized low frequency capability and a 500 KHz broadband delay line transducer. Because of a relatively high level of internal scattering in GFRP, it's very useful to have low-pass filtering capability in the instrument (to filter out scatter noise), and a delay line transducer provides better acoustic coupling in and out of a low-impedance material. We'd be happy to examine samples of your material and recommend specific equipment if you're interested.
--Tom Nelligan Panametrics, Inc. www.panametrics.com
15:05 Feb-12-2012 Re: Thickness measurement of GFRPIn Reply to Tom Nelligan at 05:34 May-23-2002 .
i also have problem similar to Ishbel. We are trying to utilize GE DMS 2 with low frequency probe as recommended by our ndt supplier. Is it really work?How about the calibration block?do we need block made of frp?
Can somebody suggest which code outline the guideline of uttm on frp material?is the guideline similar as outline in ASME V. the only difference on the material to be tested. Im i right?
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