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Half Bridge Strain Value

  1. May 4, 2009 #1
    Hi, I am using a half bridge strain gage configuration on a simply supported beam. If i get negative strain, does that mean I am getting a positive force or a negative force on the beam? I am confused since one gage is in tension and the other is in compression.

    Thanks
     
  2. jcsd
  3. May 8, 2009 #2

    Astronuc

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    A negative strain indicates a reduction in dimension, which indicates compression.

    When a solid is in uniaxial tension, there is a slight reduction in cross-sectional area, or a negative strain in the directions transverse to the tensile axis. The relationship between (ratio of) transverse contraction strain to longitudinal extension strain is expressed through Poisson's ratio.

    http://silver.neep.wisc.edu/~lakes/PoissonIntro.html
     
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