The Aerospace Corporation

Dick J Chang

James P Nokes

Pierre R Valenzuela

Francis Hai

William D Hanna

Richard P Welle

Opposing end fittings of a cylindrical tube pressure test fixture uses slanted abutting surfaces between retaining rings and ferrules that securely clamps a tube under high pressure testing. Retaining ring and ferrule friction and applied radial compression induce shear force upon the tube and prevent leaks during pressure testing.

Pressure vessel testing fixture

A shear test fixture and method determines the shear strength of a honeycomb having elongated cells extending between two ends filled with a filler material with a load applied to one end relative to the other end introducing shear stress without introducing compression or tension stress for improved shear strength testing.

Honeycomb shear testing method

A thin film stress sensor measures the maximum compressive stress between two elements that are compressed together. The sensor is formed from a thin RTV film impregnated with microballoons and reinforced with carbon fibers to restrain the lateral deformation of the RTV so that more uniform pressure can be exerted on the microballoons when the sensors are uniaxially compressed.

Microballoon impregnated fiber reinforced RTV film compression stress

A thin film stress sensor measures the maximum compressive stress between two elements that are compressed together. The sensor is formed from a thin RTV film impregnated with microballoons and reinforced with carbon fibers to restrain the lateral deformation of the RTV so that more uniform pressure can be exerted on the microballoons when the sensors are uniaxially compressed. The testing method includes applying a compressive stress up to an maximum compressive stress to rupture a first portion of the microballoons, and then applying an interrogating pressure causing acoustic emissions emitted by a second portion of the microballoons when the interrogating pressure equals the equivalent maximum compressive stress, so as to determine the maximum compressive stress.

A back-to-back, single lap-joint test fixture and method provides for uniform shear strength determination in a lap-joint area at an adhesive bond plane between a low-modulus rubber-like elastic material substrate and a stiff panel both defining a single lap-joint specimen, two of which are disposed back-to-back with the rubber substrates being constrained from lateral deformation by respective aluminum housings each having a load-transferring lip pushing upon a substrate also being pulled by load transferring dowel pins pulling upon the rubber substrate while with a restraining clamp that restrains transverse movement of the housing and rubber substrate all so as to produce only shear-type failures based on the near-incompressible nature of the rubber materials in the two back-to-back single lap-joint specimens.

Growing community of inventors

Los Angeles, CA, United States of America

Dick J Chang