Craze Initiation Criterion in Glassy Polymers Under High Pressure.

Abstract

The initiation of crazes in glassy polymers is accounted for by a single criterion according to which crazing occurs when the maximum stress at the tip of a flaw (sigma sub max) reaches a critical value. This criterion can explain the initiation of crazes in polymethylmethacrylate and polystyrene tested in tension under superposed hydrostatic pressure. A single value of sigma sub max for each of the two polymers has been calculated max and found to be independent of the applied hydrostatic pressure whether or not the polymer was exposed to the pressure-transmitting fluid. Our analysis predicts that relatively small stress-concentrations suffice for craze initiation even under remote compressive stress states (negative first stress invariant). The predicted stress concentrations are in reasonable agreement with experimentally determined values. (MM)

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Document Details

Document Type
Technical Report
Publication Date
May 11, 1979
Accession Number
ADA304409

Entities

People

  • Abdelsamie Moet
  • Eric Baer
  • Igor Palley

Organizations

  • Case Western Reserve University

Tags

DTIC Thesaurus Topics

  • Agreements
  • Classification
  • Contracts
  • Dielectric Polymers
  • Geometry
  • High Pressure
  • Hydrostatic Pressure
  • Materials
  • Mechanics
  • Military Research
  • Polystyrenes
  • Security
  • Stress Concentration
  • Stress Strain Relations
  • Stresses
  • Tensile Stress
  • Transmitting

Readers

  • Mechanical Engineering/Mechanics of Materials.
  • Polymer Science and Technology