Accession Number : AD0660277

Title :   STUDY OF MICROMECHANICAL PROPERTIES OF ADHESIVE BONDED JOINTS.

Descriptive Note : Quarterly progress rept. no. 1, 30 Jun-30 Sep 67,

Corporate Author : GENERAL PRECISION SYSTEMS INC LITTLE FALLS N J AEROSPACE RESEARCH CENTER

Personal Author(s) : Franzblau,Michael C. ; Rutherford,John L.

Report Date : 15 OCT 1967

Pagination or Media Count : 42

Abstract : The effective tensile modulus of adhesives in thin film bonded form was found to be dependent on thickness. For an epoxy-polyamide adhesive system, the effective tensile modulus increased from 520,000 psi at a bond thickness of 0.040 inch to 640,000 psi at a thickness of 0.001 inch. In the same system, the fracture stress sharply increased at bond thicknesses less than about 0.010 inches; reaching 12,000 psi for a bond thickness of less than 0.0001 inch. The shear modulus of this adhesive appears to decrease when loaded to higher stresses; in addition, there is evidence of 'work-hardening'. Preliminary work was begun on a postulate of an interfacial layer in the adhesive that has different properties than the interior of the material. As part of a separate program, the frequency dependence of the dissipation factor was measured for selected adhesive systems. It was found that there is little correlation between the mechanical properties of bulk cured polymers and the same material in thin film form in a bonded joint. For example, the effective tensile modulus is increased in thin film joints and the fracture stress has been found to increase as the bond thickness is decreased.

Descriptors :   (*PLASTICS, *BONDING), (*BONDED JOINTS, MECHANICAL PROPERTIES), FILMS, TENSILE PROPERTIES, ADHESIVES, THICKNESS, FRACTURE(MECHANICS), SHEAR STRESSES, INTERFACES, DISSIPATION FACTOR, EPOXY RESINS, POLYAMIDE PLASTICS

Subject Categories : Adhesives, Seals and Binders
      Plastics
      Couplers, Fasteners, and Joints

Distribution Statement : APPROVED FOR PUBLIC RELEASE