Accession Number : ADA308098

Title :   Torsional Shear Strength of Filament-Wound Glass-Epoxy Tubes.

Descriptive Note : Technical note,

Corporate Author : NATIONAL AERONAUTICS AND SPACE ADMINISTRATION HAMPTON VA LANGLEY RESEARCH CEN TER

Personal Author(s) : Wall, L. D., Jr. ; Card, Michael F.

PDF Url : ADA308098

Report Date : AUG 1971

Pagination or Media Count : 49

Abstract : Results are presented from torsion tests conducted on 36 multilayered, filament-wound, glass-epoxy tubes. Configurations with helical windings and with alternating helical and circumferential windings were investigated for various winding angles. Under small loadings, shear moduli deduced from linear shear stress-strain curves were found to be in reasonable agreement with analytical predictions. Under larger loadings, various degrees of nonlinearity in shear stress-strain curves were encountered, depending on the helical winding angle. Experimental torsional strengths were defined by a 0.2-percent offset yield stress or by maximum stress when large nonlinearities did not exist. These strengths were compared with torsional buckling predictions for orthotropic cylinders, and with material strength predictions based on orthotropic yield criteria and elastic stress analysis. Computed elastic buckling stresses were considerably higher than the experimental strengths for most of the test specimens except for those with only 30 deg and 45 deg windings. Experimental torsional strengths were found to correlate with conventional yield predictions if predicted yielding in certain layers were ignored or if unrealistically large transverse tensile and shear strengths of unidirectional laminae were employed in the analysis.

Descriptors :   *FILAMENT WOUND CONSTRUCTION, *FIBER REINFORCED COMPOSITES, *EPOXY COMPOSITES, *TORSION, *SHEAR STRENGTH, *GLASS REINFORCED PLASTICS, STRESS STRAIN RELATIONS, STRESS ANALYSIS, STIFFNESS, ELASTIC PROPERTIES, MODULUS OF ELASTICITY, CARBON FIBERS, GLASS, BENDING, SHELLS(STRUCTURAL FORMS), STRENGTH(MECHANICS), CYLINDRICAL BODIES, BUCKLING, AEROSPACE CRAFT, YIELD STRENGTH, BORON, FAILURE(MECHANICS), COMPRESSIVE STRENGTH, POISSON RATIO, TUBES, WINDING.

Subject Categories : Laminates and Composite Materials
      Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE