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Repeated Loads Above the Proportional Limit on 24ST Aluminum Alloy


Bull, Edward George and Mastin, Robert L. (1947) Repeated Loads Above the Proportional Limit on 24ST Aluminum Alloy. Engineer's thesis, California Institute of Technology. doi:10.7907/BN3E-8T35.


The purpose of this investigation is to study the effect of repeated tensile stresses above the proportional limit on 24ST Aluminum Alloy.

The investigation consisted of two parts: the design and building of testing apparatus which would provide a pure tension stress capable of being repeated many times a minute without shock but with a high rate of loading, and to obtain data by means of runs on prepared samples of the metal under study.

It was found that permanent deformation caused by overstress is not a useful factor in forecasting life expectancy.

It was also found that the effects of "aging" (elapsed time between overstresses), initial cold work, and magnitude of over- stresses applied all have definite influence on the ability of 24ST Aluminum Alloy to withstand further overstressing and require more thorough investigation.

It is considered that this field offers attractive possibilities for further study of the behavior of aircraft materials above the proportional limit with an eye toward increasing accuracy of airplane design.

The investigation was carried out at the Daniel Guggenheim Aeronautical Laboratory, California Institute of Technology, Pasadena, California.

Item Type:Thesis (Engineer's thesis)
Subject Keywords:Aeronautical Engineering
Degree Grantor:California Institute of Technology
Division:Engineering and Applied Science
Major Option:Aeronautics
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • Sechler, Ernest Edwin
Thesis Committee:
  • Sechler, Ernest Edwin (chair)
  • Clark, Donald S.
  • Martin, Harold Clifford
Defense Date:1 January 1947
Record Number:CaltechETD:etd-12032008-093401
Persistent URL:
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:4749
Deposited By: Imported from ETD-db
Deposited On:18 Dec 2008
Last Modified:16 Mar 2023 18:16

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