ISSN: 1945-7553
Page Count: 6

A Comparison of Methods for Determining the Shear Properties of Glass/Resin Unidirectional Composites

Loveless, HS
Supervisor, Plastics Testing Laboratory, and senior evaluation engineermember of ASTM, PPG Industries, Inc., Fiber Glass Division, Testing and Evaluation Laboratory, Shelby,N.C.

Ellis, JH
Supervisor, Plastics Testing Laboratory, and senior evaluation engineermember of ASTM, PPG Industries, Inc., Fiber Glass Division, Testing and Evaluation Laboratory, Shelby,N.C.

Abstract

This paper describes and compares three methods of test for determining the interfacial adhesive strength of the glass/resin bond in reinforced plastic (RP) unidirectional composites. Measurement of the shear properties of these materials is of fundamental importance to the fiberglass manufacturer developing optimum sizing systems for the surface treatment of glass fibers used as plastics reinforcements. A new test, developed explicitly for the shear strength determination of pultruded cylindrical composites, is described and data obtained thereby are compared with similar results obtained by torsional and short-beam methods. Unlike this new notched-rod test, both the latter tests may occasionally give tensile rather than shear failures, thus rendering their usefulness questionable, since the shear strength of the composite has not been measured under such circumstances.

Contrary to earlier work of other researchers, the current experiments suggest that the shear strength of the RP composite may exceed that of the resin matrix when the bond at the glass/resin interface has been optimized.

Keywords:
fractures (materials), composite materials, shear strength, unidirectional, pultrusion process, resin matrix, shear modulus, tensile strength, neat resin, torsion, in-plane shear, compression, interface, interfacial bond, voids, reinforcements, adhesion, tensile properties, shear, filament winding, short beam, flexural strength, fiberglass

Paper ID: JTE10544J
DOI: 10.1520/JTE10544J
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