MULTIPLE INTEGRAL REPRESENTATION OF MECHANICAL BEHAVIOR OF POLYETHYLENE.

Abstract

The response of viscoelastic solids to quasi-static loading, under conditions where non-linear theories have to be used, was investigated. Creep measurements of tension and of torsion in polyethylene specimens are described. Step loading was used and the deformations were measured optically by means of travelling microscopes for the tension experiments and by the reflection of light beams from mirrors for the torsion experiments. The deformations were too large for the theory of linear viscoelasticity to hold and the constitutive relations used were of multiple integral form; some of the kernels involved were determined. It was found that for the loading range used, two kernels were sufficient for describing pure shear deformations and three kernels were required for tension. It was also shown that in this non-linear region, the relation between shear stress and shear strain depended on whether or not dilatational stresses were present. (Author)

Document Details

Document Type
Technical Report
Publication Date
Dec 01, 1964
Accession Number
AD0609657

Entities

People

  • J. M. Lifshitz

Organizations

  • Brown University

Tags

DTIC Thesaurus Topics

  • Creep
  • Dielectric Polymers
  • Integrals
  • Measurement
  • Mechanical Properties
  • Microscopes
  • Mirrors
  • Optical Equipment
  • Optical Equipment Components
  • Physical Properties
  • Reflection
  • Shear Stresses
  • Stresses
  • Viscoelasticity

Readers

  • Calculus or Mathematical Analysis
  • Mechanical Engineering/Mechanics of Materials.