University of Illinois Urbana-Champaign

Overstraining of thick walled mild steel cylinders

Steele, M.C.; Eichberger, L.C.

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https://hdl.handle.net/2142/112550

Description

Title
Overstraining of thick walled mild steel cylinders
Author(s)
  • Steele, M.C.
  • Eichberger, L.C.
Issue Date
1955-02
Keyword(s)
  • Strain
  • Steel
Abstract
Experimental results are presented on the behavior of three mild steel cylinders (6 in. O.D. x 3 in. I.D. x 8 in. long) overstrained by internal pressure. Particular attention is made to the mechanism of yielding and the variation and character of strains measured at the bore and outside surfaces. Yield initiates and propagates in to the cylinder walls by the formation of a limited number of Lueders’ lines. Initial yield is caused by a maximum shear stress higher than that necessary to propagate yield. Lueders’ line patterns (recorded on one end face) are defined by two groupings situated approximately at opposite ends of a diameter. They follow closely the maximum shear stress trajectories. The non-homogeneous mechanism of yielding is clearly shown up by variations in strain circumferentially. Fully yielded pressures are some 10 to 14 percent lower than those predicted by theories when yield stresses from tension tests conducted at normal rates of loading are used. Axial strains, to a first approximation, are elastic, which is in agreement with a theory due to Koiter but in marked disagreement with Thomas’ theory. Small differences between experimental and theoretical shapes of pressure-circumferential strain curves are attributed to the non-homogeneous mechanism of yielding. Creep or slow yield is a feature of the tests. Lueders’ lines require time, 15 to 30 minutes, to reach an equilibrium state at a specific pressure stage. Corresponding creep is shown up in the circumferential strains.
Publisher
Department of Theoretical and Applied Mechanics. College of Engineering. University of Illinois at Urbana-Champaign
Series/Report Name or Number
  • TAM R 79
  • 1967-0375
ISSN
0073-5264
Type of Resource
text
Language
eng
Permalink
http://hdl.handle.net/2142/112550
Sponsor(s)/Grant Number(s)
Office of Ordnance Research, Ordnance Corps, Department of the Army. Contract No. DA-11-022-ORD-1527, Project No. TB2-0001(1070)
Copyright and License Information
Copyright 1955 Board of Trustees of the University of Illinois

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Technical Reports - Theoretical and Applied Mechanics (TAM) PRIMARY
TAM technical reports include manuscripts intended for publication, theses judged to have general interest, notes prepared for short courses, symposia compiled from outstanding undergraduate projects, and reports prepared for research-sponsoring agencies.