Broughton, W R; Mera, R D (1999) Environmental degradation of adhesive joints: accelerated testing. NPL Report. CMMT(A)197

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Abstract

This report evaluates environmental conditioning methods that can used for inducing accelerated moisture degradation within adhesively bonded joints. The evaluation will attempt to relate the degree of degradation (strength retention) with the level of degrading agent and exposure time, and determine any synergistic effects. The report examines durability data obtained from single-lap shear and thick adherend shear tests. Tests were conducted on bonded joints that had been either immersed in water at elevated temperatures or exposed to humid environments at elevated temperatures. Autoclave conditioning was observed to accelerate moisture absorption by a factor of 100 in polymer matrix composites and is potentially suitable for use with materials designed for hot/wet conditions. Tensile and compressive loading configurations for the thick adherend shear test have been considered. The study found that the compressive test is the more cost effective technique and potentially a faster method for generating long-term engineering data. This technique enables thinner sections to be tested.
Consideration is given to estimating the significance and limitation of the durability data generated by single-lap joint and thick adherend tensile tests and evaluates the two methods in terms of fitness for purpose in assessing environmental performance. The report provides guidance on specimen geometry, manufacture and testing, and on the validity of extrapolating data obtained from short-term accelerated tests to predicting long-term behaviour of larger bonded structures.

Item Type:	Report/Guide (NPL Report)
NPL Report No.:	CMMT(A)197
Subjects:	Advanced Materials Advanced Materials > Adhesives
Last Modified:	02 Feb 2018 13:18
URI:	http://eprintspublications.npl.co.uk/id/eprint/1238

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