THE INTERIOR ELASTIC STRESS FIELD IN A CONTINUOUS, CLOSE-PACKED FILAMENTARY COMPOSITE MATERIAL UNDER UNIAXIAL TENSION,

Abstract

Using symmetry arguments, boundary conditions are established which must hold on the lines of symmetry between neighboring filaments in an oriented filamentary composite. These conditions serve to set the problem as a special case of the mixed boundary value problem of elasticity. The composite is assumed to deform such that the normal strains in the direction of the filament axes are the same in both media. The equations of elasticity are then solved in polar coordinates so that the solution has the appropriate sixfold symmetry. The in-plane stresses are vanishingly small for the epoxy-fiberglass composite. For the silver-steel composite, the in-plane stresses reach about three percent of the average axial stress. When the filaments are close together, the periodic portions of the stress field are most important. As the filaments are more widely spaced, the stress field becomes more circularly symmetric. The phasing of the stress field is such that the radial stress is compressive at the point where the filaments are closest together and tensile at the point where the filaments are farthest apart. In all cases, the composite Young's modulus varies linearly with filament fraction.

Document Details

Document Type
Technical Report
Publication Date
Jun 01, 1965
Accession Number
AD0624572

Entities

People

  • Henry R. Piehler

Organizations

  • Massachusetts Institute of Technology

Tags

Communities of Interest

  • Air Platforms

DTIC Thesaurus Topics

  • Boundaries
  • Boundary Value Problems
  • Composite Materials
  • Elastic Properties
  • Equations
  • Fiberglass
  • Filaments
  • Materials
  • Modulus Of Elasticity
  • Radial Stress
  • Stresses
  • Symmetry

Readers

  • Plasma Physics / Magnetohydrodynamics
  • Reinforced Composite Materials
  • Structural Dynamics.

Technology Areas

  • Space