Crack Tip Strain - A Comparison of FEM Calculations and Measurements.

Abstract

Earlier crack tip strain measurements have shown a definitive three dimensional effect upon crack tip deformation. In this study, a pseudo three dimensional Finite element method (FEM) calculation is made with a composite stiffness matrix. The calculated strains agree exceedingly well with the experimental measurements. The degree of crack tip stiffening is equivalent to only 4% of the plane strain plastic zone along the crack front in a 1/4 inch thick aluminum speciment, and 8% for a 1/2 inch thick speciment. Both specimens are loaded considerably beyond general yielding. The results cast serious doubt upon the premise that the specimen, with extensive plastic deformation, can be used to determine plane strain fracture toughness.

Document Details

Document Type
Technical Report
Publication Date
Apr 01, 1975
Accession Number
ADA012217

Entities

People

  • H. W. Liu
  • Wan-liang Hu

Organizations

  • Syracuse University

Tags

Communities of Interest

  • Air Platforms

DTIC Thesaurus Topics

  • Aluminum
  • Composite Materials
  • Crack Tips
  • Cracks
  • Elements
  • Finite Element Analysis
  • Measurement
  • Physical Properties
  • Plastic Deformation
  • Stiffening
  • Stiffness
  • Three Dimensional
  • Toughness

Fields of Study

  • Materials science
  • Physics

Readers

  • Mechanical Engineering/Mechanics of Materials.