C-Shape Specimen for Tensile Radial Strength of Thick,Filament-wound Rings

Abstract

The objective of this investigation is to evaluate a new method of testing thick, C-shaped rings for determining the radial tensile strength of thick, filament-wound composite structures such as flywheel rotors. The proposed method of loading C-rings with a hydraulic jack is simpler than previously used loading methods and is shown to be quite tolerant of eccentricity of the jack. It is shown by sectioning a C-ring that residual stresses in the specimen are negligible. Based on a detailed stress analysis and post-failure inspections of appropriately dimensioned specimens, it is concluded that failure is caused by radial tensile stress at a single critical location in the specimen. The radial tensile strengths of four candidate flywheel rotor materials measured with C-rings were generally less than strengths measured with flexure specimens. The simplicity of specimen preparation and testing by the proposed method, in conjunction with promising early results, suggests that the C-ring test method is suitable for widespread use and possible standardization.