Lunsford, L. R.
Lockheed Missiles and Space Co., Sunnyvale, Calif.
Pages: 9 Published: Jan 1963
The theoretical expressions presently being developed for the design and analysis of bonded joints invariably involve the shear strength and shear modulus of elasticity of the adhesive. A brief summary of currently used adhesive shear specimens indicates that these specimens do not provide a means of obtaining actual material properties. In order to obtain these data for adhesives as they occur in thin layers restrained by the relatively higher modulus of the adherends, an idealized specimen simulating the torque loading of a large-diameter, thin-walled tube has been developed.
A torsional shear load which produces peripherally uniform shear stresses in the adhesive is applied to the specimen. The maximum shear stress at failure represents the ultimate shear strength of the adhesive. By carefully measuring the adhesive strain as a function of load, the stress-strain curve and shear modulus of elasticity of the adhesive can be obtained. The test has proved to be quite sensitive to variations in adhesive quality and is currently being used to determine the material properties of various adhesives.
Paper ID: STP45100S