A Method for Dynamic Fracture Initiation Testing of Ceramics

Abstract

An experimental method is described whereby the dynamic fracture initiation toughness of ceramics and ceramic composites can be measured in pure tension or pure torsion at stress intensity factor rates of 100,000 to 1,000,000 MPA sq rt m/s. In this procedure, circumferentially-notched cylindrical rods are subjected to uniaxial cyclic compression at room temperature to introduce a self-arresting, concentric Mode I fatigue pre-crack, following the technique presented by Suresh et al. (1987) and Suresh and Tschegg (1987). Subsequently, dynamic fracture initiation is effected by stress wave loading with a sharp- fronted pulse which subjects the specimen to a dynamic load inducing either Mode I or Mode III fracture. Instrumentation appropriate to the loading mode provides a record of average stress at the fracture site as a function of time. The capability of this method to yield highly reproducible dynamic fracture initiation toughness values for ceramics is demonstrated with the aid of experiments conducted on a polycrystalline aluminum oxide.

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Document Details

Document Type
Technical Report
Publication Date
May 01, 1987
Accession Number
ADA182791

Entities

People

  • E. R. Bopp
  • J. Duffy
  • K. Cho
  • S. Suresh

Organizations

  • Brown University

Tags

Communities of Interest

  • Advanced Electronics
  • Air Platforms

DTIC Thesaurus Topics

  • Aluminum Oxides
  • Ceramic Matrix Composites
  • Cracks
  • Failure Mode And Effect Analysis
  • Fracture (Mechanics)
  • Grain Size
  • Materials
  • Materials Science
  • Materials Testing
  • Mechanical Properties
  • Mechanics
  • Schematic Diagrams
  • Strain Gages
  • Stress Intensity Factors
  • Stress Waves
  • Stresses
  • Test Methods

Readers

  • Materials Science (Mechanical Engineering).
  • Structural Dynamics.