The Room-Temperature Shapes of Four-Layer Unsymmetric Cross-Fly Laminates

Abstract

A previous approximate theory for predicting the room-temperature shapes of unsymmetric laminates is examined in light of the assumptions regarding the inplane strains. The previous theory, which was a geometrically nonlinear extension of classical lamination theory, was felt to be restrictive and this paper develops a new theory in which these restrictions are relaxed. It is shown that despite the previous concern, there is little difference between the previous theory and this theory. This paper presents numerical results for the inplane residual strains of unsymmetric laminates which have cooled from curing into a cylindrical room-temperature shape. It is shown that the residual strains are compressive and practically independent of spatial location on the laminate. In another facet of the paper, the room-temperature shapes of all four-layer unsymmetric cross-ply laminates are predicted. There are only four unique stacking arrangements for this category of laminates and it is shown that their shapes are a strong function of their stacking arrangement. Keywords: Composite materials, Unsymmetric laminates, Thermal stresses, Thermal buckling, Residual stresses, Cross-ply laminates.

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Document Details

Document Type
Technical Report
Publication Date
Apr 01, 1982
Accession Number
ADA215476

Entities

People

  • Michael W. Hyer

Organizations

  • Virginia Tech

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Communities of Interest

  • Air Platforms
  • Energy and Power Technologies

DTIC Thesaurus Topics

  • Abstracts
  • Air Force
  • Classification
  • Climate Change
  • Composite Materials
  • Curvature
  • Elastic Properties
  • Elongation
  • Engineering
  • Equations
  • Laminates
  • Literature Surveys
  • Materials
  • Mechanics
  • Potential Energy
  • Shape
  • Stresses

Readers

  • Calculus or Mathematical Analysis
  • Powder metallurgy of Titanium alloys.
  • Structural Health Monitoring of Composite Structures.