Degradation of single lap adhesively bonded composite joints due to hot water ageing


SOYKÖK İ. F.

Journal of Adhesion, vol.93, no.5, pp.357-374, 2017 (SCI-Expanded, Scopus) identifier

  • Publication Type: Article / Article
  • Volume: 93 Issue: 5
  • Publication Date: 2017
  • Doi Number: 10.1080/00218464.2015.1076340
  • Journal Name: Journal of Adhesion
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.357-374
  • Keywords: Aerospace, ageing, composites, destructive testing, epoxy/epoxides
  • Manisa Celal Bayar University Affiliated: Yes

Abstract

Joints, which are the most critical part of fibre-reinforced epoxy plastic structures, can be exposed to continuous hydrothermal action. In order to estimate their long-term performance, an accelerated ageing process was performed on adhesively bonded joints of glass-fibre-reinforced epoxy plastics with [0/90/45/−45]s fibre orientations. Changes in the static tensile properties of single lap shear samples due to hot-wet exposure were investigated for one- and two-week immersion periods and at three different water temperatures (50°C, 70°C, and 90°C). Both the ageing temperature and immersion time were found to be influential on load–displacement characteristics, maximum failure loads, and apparent failure modes of joints bonded with Loctite Hysol-9466 epoxy type adhesive. Due to the hydrothermal exposure, maximum failure loads, distance to failure values, and stiffness of joints decreased by a certain amount in proportion to the immersion time and temperature. While unaged samples and those aged at 50°C and 70°C exhibited mainly light fibre-tear (LFT) failures, the samples treated at 90°C ruptured through the material cross section in stock-break (SB) failure mode.