two things about Failure Theories.
1)The maximum shear failure theory. Plastic deformation occurs whenever the
max. shear stress exceeds 1/2 of the yield stress.
2)MAx. pricncipal stress failure theory. Failure is certain whenever one of
the principal stress exceeded the yield stress of the matl at temp.
The above relates of course to the three mutually perpendicualr princiapl stress and is basically the basis of the b31 max. stress intensity criterion. Furthermore it does not exclude the effect of the axial stress (longitudinal). A distiction has to be made between the primary and secondary stress load when applying relevant code equation.
-----Original Message-----
From: trajyagu@ltcis.ltindia.com [mailto:trajyagu@ltcis.ltindia.com]
But if you see the equation of expansion stress as per B 31.3, you will find
that
it takes only bending and torsioal stresses in calculations and not the
axial stresses. If you model a straight line with anchors at both ends and
temperature around 500, code stress (expansion stress) will be zero, but
actually due to high axial stresses, it is going to fail. The problem is
neither code considers axial stresses nor it takes buckling effects into
account.
Can anyone throw more light on this ?
Received on Sat Apr 20 04:25:00 2002
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