Anelastic Properties of Mild Steel at Moderate Stresses

Morrison, Duncan M (1954) Anelastic Properties of Mild Steel at Moderate Stresses. PhD thesis, University of Glasgow.

Abstract

This thesis describes an experimental investigation of the elastic hysteresis and other non-linear effects occurring in mild steel at stresses from about 2 ton/in squared up to the yield point. The design and construction of a new apparatus for making measurements of these quantities is also described. An important feature of this equipment is that the absolute shape of the hysteresis loop for a bending specimen is obtained and not merely the area or strain width. Due to this feature measurements can also be made of the departure from true linearity in the stress-strain diagram of the material for a single loading. The results obtained on a few mild steel specimens agree well with those obtained by other investigators in so far as they are directly comparable. A remarkable feature of the experimental results. is that for moderate stress ranges the main curvature in the hysteresis loop occurs in the unloading part of the stress cycle. Although this is in contradiction with the tacitly accepted form of the loop it is shown that it does in fact agree with (1) the accepted relationship between energy dissipation and stress amplitude. (2) the observed results for the deviation from true linearity in a single loading. (3) the hypothesis that elastic hysteresis is due to plastic flow occurring at numerous discontinuities in the bulk of the material. A mathematical section deals with the problem of determining the damping coefficient of a uniformly stressed material from the experimental results obtained on a specimen having an arbitrary stress distribution. Since the preparation of this thesis a description of the apparatus together with some preliminary results has been published in Engineering p. 141, Volume 177, (1954).

• Item Type: Thesis (PhD)
• Qualification Level: Doctoral
• Keywords: Materials science
• Date of Award: 1954
• Depositing User: Enlighten Team
• Unique ID: glathesis:1954-79091
• Copyright: Copyright of this thesis is held by the author.
• Date Deposited: 05 Mar 2020 11:44
• Last Modified: 05 Mar 2020 11:44
• URI: https://theses.gla.ac.uk/id/eprint/79091