Statistics of Crack Growth of a Superalloy under Sustained Load

Abstract

A statistically-formulated fracture mechanics model for crack growth under sustained load is used to analyze crack growth data from 23 compact tension specimens of IN100, a turbojet engine disc material. The procedures characterize crack growth rates is a lognormal random variable. The mean and standard deviation of the growth rate are determined from test data using the method of maximum likelihood. The method estimates crack growth rate parameters for each test specimen result. From these estimates, a lognormal creep crack growth rate model is developed from which is derived a statistical distribution of the crack size at any time. The distribution of time to reach some critical crack size is also presented. These distributions allow for the determination of the effect of hold time in the loading cycle on the life prediction of gas turbine engine discs.

Open PDF

Document Details

Document Type
Technical Report
Publication Date
Dec 01, 1982
Accession Number
ADA130395

Entities

People

  • J. N. Yang
  • R. C. Donath

Organizations

  • Wright Laboratory

Tags

DTIC Thesaurus Topics

  • Aeronautical Laboratories
  • Air Force
  • Air Force Facilities
  • Blood Coagulation Factors
  • Crack Propagation
  • Databases
  • Distribution Functions
  • Engineering
  • Fracture (Mechanics)
  • Gas Turbines
  • Intensity
  • Materials Laboratories
  • Mechanics
  • Normal Distribution
  • Random Variables
  • Statistics
  • Turbines

Readers

  • Materials Science (Mechanical Engineering).
  • Statistical inference.