Effects of Surface Preparation on Long-Term Durability of Composite Adhesive Bonds
Abstract
The long-term effects of surface preparation techniques for composite bonded joints are addressed. Several potential factors are evaluated, concentrating on the effects of peel plies and grit blasting on the fracture toughness and failure mode of adhesively bonded composites. An evaluation of the floating roller peel test configuration is described, where the intent was to extract quantitative data from this commonly used quality control test method. Subsequently, an alternate form of the double cantilever beam (DCB) test was developed and used for a sequence of test evaluations. The research will aid the interpretation of a form of the wedge test where the usual aluminum adherends are replaced by composite adherends. DCB tests have shown that nylon peel ply(*) surfaces tend to precipitate interfacial failures and intermittent crack propagation, with reduced loads and crack opening displacements, hence, significantly lower critical strain energy release rates (G(sub Ic)) than equivalent polytetraflouroethylene (PTFE) vacuum bag surfaces. Additionally, grit-blasted bonded joints tend to have higher failure load and G(sub Ic) values than nonblasted ones, though the mode of failure (interfacial or cohesive) is unchanged. Several improvements to specimen preparation and testing, including a custom bonding jig, bondline thickness control methods, and an alternate version of the wedge crack test are also described.
Document Details
- Document Type
- Technical Report
- Publication Date
- Apr 01, 2001
- Accession Number
- ADA391443
Entities
People
- Jason Bardis
- Keith Kedward
Organizations
- University of California, Santa Barbara