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Results for “STRESSED SKIN”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 91 records · Page 5
All sourcesNASA NTRSDOE OSTI
NASA NTRS1987

Calculation of stresses and forces between the skin and stiffener in composite panels

A methodology for computing the stresses at the interface between the skin and stiffener in stiffened composite panels is described. The methodology is based on finite-element analyses and on elasticity solution. The finite-element analyses are standard, while the elasticity solution is based on eigenvalue expansions of the stress function. The eigenvalue expansions are assumed to be valid in the local region where the stiffener flange terminates. The local elasticity solution is coupled to the global finite-element analysis using collocation on the boundary of the local region. Accuracy and convergence of the method are discussed and several examples of its utility are presented.

Hyer, M. W.↗
NASA NTRS1950

The Effect of Nonuniform Temperature Distributions on the Stresses and Distortions of Stiffened-Shell Structures

The structural effects of nonuniform temperature distributions, such as those produced by aerodynamic heating or thermal ice-prevention systems, are discussed and found to be of two types: The introduction of thermal stresses and distortions as a result of restrained thermal expansion and a change in the stresses and distortions produced by the applied loads as a result of the variation of elastic properties of materials with temperature. These effects are illustrated by sample analyses of the stress and distortion distributions of simple box beams and by calculation of the stresses on a typical wing section.

ALUMINUM ALLOYS - ALCOA 75ST6 - ELASTICITY↗
NASA NTRS1939

Compressive Tests of a Monocoque Box

A monocoque box specimen of aluminum alloy was subjected to end compression and the strains in the stringers were measured up to loads at which permanent set became noticeable. The stringer strains at low loads agreed closely with those computed from the assumption of uniform stress distribution. Buckling of the 0.026-inch sheet between stringers and of the 0.075-inch shear web took place at stresses in accord with theoretical values. Permanent set became noticeable at a load of 115,200 pounds, corresponding to an average stringer stress of about 16,000 pounds per square inch. The measured average strain above the first buckling load was within 2 percent of the theoretical strain as calculated from the dimensions of the box and effective width formulas due to Marguerre and to Cox.

BOXES, MONOCOQUE - STRENGTH, COMPRESSIVE↗
NASA NTRS1991

Interlaminar stress analysis at the skin-stiffener interface of a grid-stiffened composite panel

Results are presented of an analysis of the interlaminar stress components at the skin-wrap, skin-core, and wrap-core interfaces for an advanced-concept stiffened panel using a global/local finite element procedure. The procedure consists of a global model of two-dimensional shell elements that is used to design a grid-stiffened panel with blade-type stiffeners, a local model of three-dimensional solid elements that is used to compute interlaminar stress components, and a scheme devised to assign displacement boundary conditions for the local model that are derived from displacement and rotation data of a few nodes of the global model. The interlaminar stresses for this panel design were found to be well below typical tensile normal and shearing strengths of a graphite-epoxy material.

Wiggenraad, J. F. M.↗