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8/8/2019 Von Mises Material Properties
http://slidepdf.com/reader/full/von-mises-material-properties 1/4
8/8/2019 Von Mises Material Properties
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Biaxial stress-strain curve. In the
biaxial case, any combination of
stress inside the initial yield
surface (surface A) is in the elasticregion. Once the part is taken
beyond the initial yield surface, the
part experiences plasticdeformation.
With isotropic hardening, the
center of the yield surface remains
fixed but the size of the surface
increases. Any stress state inside
the new yield surface (surface B)
will experience elasticdeformation; new plastic
deformation occurs when the stressstate reaches surface B.
Figure 1: Isotropic Hardening
Uniaxial stress-strain curve. If the
part is taken beyond the yield
stress, it begins to deform
plastically. If taken to a maximumstress (point A) and the load is
released, it unloads along the
dashed line. If the part is loaded
again, no additional plastic
deformation occurs until the stressreaches point A.
If the part is put into compression,
it compresses elastically along the
dashed line until it reaches point B,and then it yields in compression.
With kinematic hardening, the
change in stress from point A to point B is twice the yield stress.
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strain hardening modulus =Ultimate Strength - Yield Strength
(Elongation at 2 in)/100 - yield strain
where yield strain is the strain corresponding to the yield strength, or yield strain = (Yield
Strength) / (Modulus of Elasticity). The Ultimate Strength, Yield Strength, Elongation at 2 in,
and Modulus of Elasticity are stored in the material library.
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