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The Influence of Stress and Temperature upon the Time to Initiate Plastic Deformation in an Annealed Low Carbon Steel


Wood, David Shotwell (1949) The Influence of Stress and Temperature upon the Time to Initiate Plastic Deformation in an Annealed Low Carbon Steel. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/5355-1Z24.


An experimental investigation of the time delay for initiation of plastic deformation in an annealed low carbon steel is described. The delay time is determined as a function of the applied stress at temperatures of -75°F, 73°F, 150°F, and 250°F. The stress is applied in a continuous manner within a period of about 7 millisec, and the stress is maintained substantially constant thereafter, until plastic deformation begins. At any given temperature, the relation between the logarithm of the delay time and the stress is found to consist of two straight lines which join together at a point in the delay time and the stress plane. One is a line of constant stress, and the other is a line along which the logarithm of the delay time decreases linearly as the stress is increased above the constant stress line. The experimental results are compared with a dislocation theory of yielding in low carbon steel which has been given by A.H. Cottrell and B. A. Bilby (21)*. It is shown that this theory, in its present form, does not describe the experimental results adequately. Two suggestions are made for modification and addition to the theory which might lead to satisfactory agreement with the experimental observations.

*The figures appearing in the parentheses refer to the references listed at the end of this thesis.

Item Type:Thesis (Dissertation (Ph.D.))
Subject Keywords:(Mechanical Engineering and Physics)
Degree Grantor:California Institute of Technology
Division:Engineering and Applied Science
Major Option:Mechanical Engineering
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • Clark, Donald S.
Thesis Committee:
  • Unknown, Unknown
Defense Date:1 January 1949
Record Number:CaltechETD:etd-10222002-111754
Persistent URL:
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:4206
Deposited By: Imported from ETD-db
Deposited On:22 Oct 2002
Last Modified:29 Mar 2023 17:33

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PDF (Wood_ds_1949.pdf) - Final Version
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