Re: [Vo]:Question regarding basic solid mechanics and one directional applied stress

[R C Macaulay]

Howdy David,
A brain teaser question. The answer is yes if you accept that expansion and 
contraction actually occurs depending on the materials of the cylinder. Mention 
of the cylinder being solid presents another teaser. Certain solids "react" to 
being stressed. Predictive science of materials is become the cutting edge 
technology whereas in the past we used empirical tests alone. LIke non-invasive 
quality control tests, predictive science is what the Russians face in 
discovering what is happening with their  Soyuv space capsule re-entry 
problems. You may be working on that task so I wish you well.
You may set up a testing method of proving that the stress caculated is indeed 
negative by building a sorta makeshift " air comparison picnometer" of  a 
version used for density measurement of dry drilling mud. Fun stuff.
Richard
  ----- Original Message ----- 
  From: David Jonsson 
  To: vortex-l@eskimo.com 
  Sent: Sunday, May 04, 2008 3:36 PM
  Subject: [Vo]:Question regarding basic solid mechanics and one directional 
applied stress


  Hi

  If I put a wheight on a vertical cylinder it will be shortened and its radius 
will be somewhat increased. I wonder if the radial increase is considered a 
negative stress in radial direction?

  Is the stress tensor something like this?

       -a  0  0
  T=  0  0  0
        0  0  b

  Where a and b are positive values and the coordinates are cylindrical ρ, φ, z 
(ISO 31-11).

  David

  -- 
  David Jonsson 
  Sweden
  phone callto:+46703000370



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