Accession Number:

ADA061805

Title:

Fracture Mechanics for Structural Adhesive Bonds. Part 2

Descriptive Note:

Final rept. 1 Jul 1977-30 Jun 1978 on Phase 2

Corporate Author:

LOCKHEED-CALIFORNIA CO BURBANK

Report Date:

1978-08-01

Pagination or Media Count:

107.0

Abstract:

Research results are presented of crack propagation tests and fracture mechanics analysis of laboratory joints and specimens bonded with FM-73 adhesive and containing bondline cracks. New baseline specimens and tests are developed, analyzed, and used for Mode I and mixed-mode fracture mechanics testing of adhesives. Baseline test data are reported for FM-73 including increasing load fracture toughness tests in laboratory air and sustained-load, hot-water-immersed tests. Results of fatigue crack growth tests are presented at two stress ratios, two environments, and three cyclic frequencies for three different baseline specimen geometries and three different mixes of Modes I and II. Fracture mechanics prediction methodology is demonstrated using results of nine dadN tests of structural joint specimens immersed in hot water. Two different finite element analysis procedures are used to calculate strain energy release rate as a function of crack size. Then the baseline data enable crack growth rate estimation. Multiple cracking is considered based on measurements of final crack sizes on the fracture surfaces on the failed specimens. The estimated crack growth rates correlate well with the experimental data.

Subject Categories:

  • Aircraft
  • Couplers, Fasteners and Joints
  • Mechanics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE