Measurement of the through-thickness strength of composites

Thesis

This research deals with the mechanical characterisation of thick composite laminates in the through-thickness direction. Three independent glass fibre/epoxy laminate configurations, namely cross, quasi-isotropic, and woven, plies were investigated. Six specimen configurations, of which two were developed herein, were employed in order to determine the strength behaviour of these three laminate configurations when subjected to interlaminar shear and interlaminar tensile stresses in isolation and in combination. The stress and strain distributions were estimated using the ABAQUS FEA package. The strain distribution obtained thereby was verified experimentally via Moirandeacute; interferometry which records the exact strain field at the test section. A two dimensional failure envelope is defined for each laminate configuration using the experimentally obtained data. All three independent laminate configurations exhibited almost identical failure envelopes. The woven laminate exhibited superior interlaminar shear strength when subjected to combined interlaminar shear and interlaminar tensile stresses, whereas the cross-ply laminate exhibited superior interlaminar tensile strength when subjected to the same combination of stress. The characteristics of the quasi-isotropic laminate were similar to that of the cross-ply laminate. A partial three dimensional failure envelope was also defined for the materials tested.

Authors: Taniguchi, S; Taniguchi, Shinro

• Publication date: 1998
• DOI: 10.5287/ora-zbvyme9rr
• Type of award: DPhil
• Level of award: Doctoral
• Awarding institution: University of Oxford
• Language: English
• Subjects: Glass-reinforced plastics; Epoxy resins; Glass fibers