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Repeated Loads Above the Proportional Limit on 24st Aluminum Alloy


Joga Rao, Chintakindi Venkata (1948) Repeated Loads Above the Proportional Limit on 24st Aluminum Alloy. Engineer's thesis, California Institute of Technology. doi:10.7907/V8T5-YS83.


The purpose of this investigation is to study the effects of repeated tensile stresses above the proportional limit on 24ST Aluminum Alloy. The investigation consisted of three parts: 1. An investigation of the effects of the application of repeated tensile stress above the proportional limit for 500 cycles followed by a higher repeated tensile stress up to 5,000 cycles. 2. An investigation of the effects of changing the number of cycles of pre-stress. 3. An Investigation of the effects of aging. It was found that permanent deformation caused by over-stress is not a useful factor in forecasting life expectancy. It was also found that the effects of aging, initial cold work, and magnitude of overstresses applied all have definite influence on the ability of 24ST Aluminum Alloy to withstand further overstressing and require considerably more thorough investigation. It is considered that this field offers attractive possibilities for further study of the behavior of aircraft materials with the objective of increased accuracy in airplane design. The investigation was carried out in collaboration with Conrad N. Nelson, Captain, U. S. Air Force at the Daniel Guggenheim Aeronautical Laboratory, California Institute of Technology, Pasadena, California.

Item Type:Thesis (Engineer's thesis)
Subject Keywords:Aeronautics
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:
  • Unknown, Unknown
Defense Date:1 January 1948
Record Number:CaltechETD:etd-12162008-133111
Persistent URL:
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:5022
Deposited By: Imported from ETD-db
Deposited On:14 Jan 2009
Last Modified:22 Mar 2023 18:21

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PDF (Rao_cvj_1948.pdf) - Final Version
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