Accession Number : AD0742124

Title :   Fracture Mechanics for an Interfacial Crack Between Adhesively Bonded Dissimilar Materials,

Corporate Author : ILLINOIS UNIV URBANA DEPT OF THEORETICAL AND APPLIED MECHANICS

Personal Author(s) : Wang,Charles Yi-jer

Report Date : MAR 1972

Pagination or Media Count : 101

Abstract : A plate composed of two dissimilar materials, bonded together along a straight line with a center crack was studied. This problem represents an idealization of an adhesive joint or a composite structure with an interfacial flaw or crack caused by faulty joining techniques. Common examples are imperfections, voids, or broken bonds on the composite interface. Combined with the finite element technique, the strain energy method and the J-integral method have been extended to a bi-material problem to calculate the value of the strain energy rate. A general relationship between strain energy rate and total stress intensity factor is then derived using the crack closure technique. The ratio of stress intensity factors was also examined. The numerical analysis concentrated on three categories of composite materials with moduli ratio 1, 20, and 120. These results provide a complete crack-tip stress analysis and are needed for the study and understanding of the fracture mechanics of bi-material problems. Lastly, the compliance method was employed for experimental verification of the numerical results. An aluminum alloy-epoxy bi-material plate with a moduli ratio equal to 20 was examined. This study has yielded useful results in terms of the analytical tools to guide further experimental fracture studies of adhesive joints and composite materials. (Author, modified-PL)

Descriptors :   (*BONDED JOINTS, *FRACTURE(MECHANICS)), CRACKS, INTERFACES, COMPOSITE MATERIALS, STRESSES, NUMERICAL ANALYSIS, THESES

Subject Categories : Couplers, Fasteners, and Joints

Distribution Statement : APPROVED FOR PUBLIC RELEASE