Accession Number : AD0768689

Title :   Study of the Onset of Permanent Deformation in Structurally Bonded Joints.

Descriptive Note : Final rept. 19 Nov 71-19 Apr 73,

Corporate Author : AUBURN UNIV ALA

Personal Author(s) : Jemian,Wartan A. ; Wilcox,Roy C.

Report Date : AUG 1973

Pagination or Media Count : 84

Abstract : The elastic sample compliance vs. crack length curve for adhesive bonded samples in the lap-shear configuration was found to have a positive curvature and an increasing slope with increasing crack length. The effects of various sample parameters on the compliance variation curve were determined. This research was conducted by experimentation and finite element computation. The materials were epoxy adhesives and aluminum alloy and alclad alloy adherends. Fracture surfaces were studied by direct observation and by scanning electron and replica electron microscopy. Features of plastic flow, slow and rapid crack extension were observed. Slow crack growth was studied by the use of samples bonded with conducting epoxies. A STANDARD PROCEDURE FOR FRACTURE TOUGHNESS TESTING WITH SAMPLES IN THE LAP-SHEAR CONFIGURATION WAS OUTLINED. This included the specifi-cation of conditions that must be satisfied, and charts for making the final determination from the sample breaking load and the observed starting crack size. (Author, modified-PL)

Descriptors :   (*BONDED JOINTS, DEFORMATION), FRACTURE(MECHANICS), CRACK PROPAGATION, CREEP, ADHESIVES, EPOXY RESINS, ALUMINUM ALLOYS

Subject Categories : Aircraft
      Couplers, Fasteners, and Joints

Distribution Statement : APPROVED FOR PUBLIC RELEASE