Session A: Damage Tolerance in Helicopters - Situation Today

Abstract

A proper validation of the type of flaws and the method used to test flawed elements is considered essential. An example is provided detailing the evidences to validate scratches in aluminum. A survey of service data and test evidences provided information on a severe manufacturing scratch, showing that plastic deformation and notch radius at crack tip are the relevant parameters for the crack initiation. The crack growing path of a component failed in service showed negligible effects of the notch were plastic deformation had occurred, although the crack was growing very close to the scratch. Milling an U' shaped gauge in SCT specimens tested at CAL made a very sharp scratch. Considering the scratch like a crack, AK was computed for each coupon. Depending on the applied stress, specimens failed if the AK was higher than the threshold value, and they gave run out if lower.

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Document Details

Document Type
Technical Report
Publication Date
Jan 01, 2000
Accession Number
ADA394869

Entities

People

  • Ugo Mariani

Organizations

  • Cranfield University

Tags

Communities of Interest

  • Air Platforms
  • Biomedical
  • Ground and Sea Platforms

DTIC Thesaurus Topics

  • Aerospace Industry
  • Air Force
  • Aircraft Industry
  • Aircrafts
  • Airframes
  • Aluminum
  • Aluminum Alloys
  • Composite Materials
  • Damage Tolerance
  • Engineering
  • Failure Mode And Effect Analysis
  • Fatigue Tests (Mechanics)
  • Fracture (Mechanics)
  • Fuselages
  • Materials
  • Mechanics
  • Test Methods

Readers

  • Educational Psychology
  • Metallurgy
  • Regression Analysis.