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Crack Propagation in Aluminum Alloy Sheet Materials under Flight-Simulation Loading.

AD715331

Publication Date	1970
Personal Author	Schijve, J.; Jacobs, F. A.; Tromp, P. J.
Page Count	77
Abstract	A large number of flight-simulation tests were carried out on sheet specimens of 7075-T6 and 2024-T3 clad material. A gust load spectrum was adopted and a flight-by--flight loading was applied. The investigation is essentially concerned with macrocrack propagation although a few exploratory tests were conducted on the crack nucleation period. The major trends emerging from tests with a variety of loading programs are: (1) The omission of taxiing loads from the ground-to-air cycles did not affect the crack propagation. (2) The sequence of the gust cycles in a flight (random, programmed, reversed gust cycles) did not have a significant influence on the crack propagation. (3) Omission of gust cycles with small amplitudes systematically increased the crack propagation life. (4) The most predominant effect on the crack propagation was coming from the maximum gust amplitude included in the test. Increasing this amplitude gave a large increase of the crack propagation life. (5) Application in each flight of a single gust load only, namely the largest upward gust load, increased the crack propagation life three times. (6) Omission of the ground-to-air cycle increased the life 1.5-1.8 times. The discussion and the analysis of the results include such aspects as fractographic analysis, possible mechanisms for interaction effects between load cycles of different magnitudes and damage calculations. (Author)
Keywords	Aluminum alloys Crack propagation Sheets Aerodynamic loading Fatigue(Mechanics) Loading(Mechanics) Netherlands Aluminum alloy 7075 Aluminum alloy 2024
Source Agency	Invalid Source Agency Code
NTIS Subject Category	71N - Nonferrous Metals & Alloys
Corporate Authors	National Aerospace Lab Amsterdam (Netherlands)
Supplemental Notes	Supersedes Rept. no. NLR-TR-68117-U dated Dec 68, AD-692 467.
Document Type	Technical Report
Title Note	Final rept. 1 Sep 67-30 Nov 68.
NTIS Issue Number	197102
Contract Number	F61052-67-C-0076

Crack Propagation in Aluminum Alloy Sheet Materials under Flight-Simulation Loading.

Crack Propagation in Aluminum Alloy Sheet Materials under Flight-Simulation Loading.
AD715331

Publication Date	1970
Personal Author	Schijve, J.; Jacobs, F. A.; Tromp, P. J.
Page Count	77
Abstract	A large number of flight-simulation tests were carried out on sheet specimens of 7075-T6 and 2024-T3 clad material. A gust load spectrum was adopted and a flight-by--flight loading was applied. The investigation is essentially concerned with macrocrack propagation although a few exploratory tests were conducted on the crack nucleation period. The major trends emerging from tests with a variety of loading programs are: (1) The omission of taxiing loads from the ground-to-air cycles did not affect the crack propagation. (2) The sequence of the gust cycles in a flight (random, programmed, reversed gust cycles) did not have a significant influence on the crack propagation. (3) Omission of gust cycles with small amplitudes systematically increased the crack propagation life. (4) The most predominant effect on the crack propagation was coming from the maximum gust amplitude included in the test. Increasing this amplitude gave a large increase of the crack propagation life. (5) Application in each flight of a single gust load only, namely the largest upward gust load, increased the crack propagation life three times. (6) Omission of the ground-to-air cycle increased the life 1.5-1.8 times. The discussion and the analysis of the results include such aspects as fractographic analysis, possible mechanisms for interaction effects between load cycles of different magnitudes and damage calculations. (Author)
Keywords	Aluminum alloys Crack propagation Sheets Aerodynamic loading Fatigue(Mechanics) Loading(Mechanics) Netherlands Aluminum alloy 7075 Aluminum alloy 2024
Source Agency	Invalid Source Agency Code
NTIS Subject Category	71N - Nonferrous Metals & Alloys
Corporate Authors	National Aerospace Lab Amsterdam (Netherlands)
Supplemental Notes	Supersedes Rept. no. NLR-TR-68117-U dated Dec 68, AD-692 467.
Document Type	Technical Report
Title Note	Final rept. 1 Sep 67-30 Nov 68.
NTIS Issue Number	197102
Contract Number	F61052-67-C-0076