Fracture Mechanics for Structural Adhesive Bonds
Abstract
Tests and analyses were conducted to develop and demonstrate the fracture mechanics methodology to predict the growth of bondline flaws in adhesively bonded primary aircraft structure. The development and use of a new baseline specimen for testing bondline cracks in combined Modes I and II is described Specimen development work on other adhesive fracture mechanics specimens including modes I and III is described. Fracture mechanics data for AF-55S adhesive are presented covering fatigue, sustained and monotonically increasing loading, in laboratory air and hot water, in Pure Mode I, and mixed Modes I and II. Adhesive bondline crack growth data are presented from fatigue tests of larger structural bonded single lap joints with initial bondline flaws. Techniques are demonstrated for growth monitoring both ultrasonically and by a compliance technique. A fracture mechanics analysis estimate of bondline crack growth rates in these tests is described, and the estimated rates are compared to the actual monitored crack growth rates. Based on this work an evaluation is made of fracture mechanics methodology as applied to bondline cracks in adhesively bonded aircraft structure.
Document Details
- Document Type
- Technical Report
- Publication Date
- Oct 01, 1977
- Accession Number
- ADA054023
Entities
People
- S. Mostovoy
- S. T. Chiu
- T. R. Brussat
Organizations
- Lockheed Martin