FATIGUE CRACKING RATES AND RESIDUAL STRENGTHS OF EIGHT ALUMINIUM SHEET ALLOYS

Abstract

Eight aluminium sheet alloys were tested as 6 1/2-in.-wide 16 SWG panels containing 1/2-in. central transverse slots, to compare the propagation rates of fatigue cracks which grew from the slots under P = p type stressing. The results are given as cracking rate vs crack length curves. With the lowest stress cycle, 14,000 = 2000 psi, cracking rates at 1 in. crack lengths ranged from 0.0000016 in/cycle in Hiduminium 54 to 0.000011 in/cycle in DTD.687A, the rate in DTD.5070 sheet being 0.0000036 in/cycle. With the highest stress cycle, 18,000 = 4000 psi, cracking rates at 1-in. crack lengths were about 10 to 20 times faster, and again the DTD.5070 sheet had an intermediate rate similar to those of DTD.546B and 2024-T81. Heating 2024-T81 and DTD.5070 panels for 1000 hours at 150 C caused only small changes in cracking rates, and rates measured in tests at 150 C were very similar to those at room temperature. Residual strengths at 1 in. crack lengths ranged from 37% for X 2020 to 67% for DTD.546B and Hiduminium 54, with DTD.5070 retaining 64%.

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Document Details

Document Type
Technical Report
Publication Date
Oct 01, 1964
Accession Number
AD0464371

Entities

People

  • N. J. Gunn

Organizations

  • Royal Aircraft Establishment

Tags

Communities of Interest

  • Air Platforms

DTIC Thesaurus Topics

  • Alloys
  • Aluminum
  • Aluminum Alloys
  • Arc Lamps
  • Carbon Arc Lamps
  • Crack Propagation
  • Cracks
  • Fatigue Cracking
  • Government Procurement
  • Heating
  • Materials
  • Measurement
  • Residuals
  • Slots
  • Standards
  • Temperature Gradients
  • Tensile Strength

Fields of Study

  • Materials science

Readers

  • Mathematics or Statistics
  • Metallurgy
  • Structural Health Monitoring of Composite Structures.