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4.3 Yield Criteria

Cannot perform tests for all combinations of 3Dloading so we need yield criterion to generalize

from small number of tests. What are the ideal properties of a 3D yield

criterion?

We usually visualize yield criterion by a surfacein principal stress space. Why?

We also calculate effectivestress to comparewith yield stress.

( )

( )

ij

ij

f ,Y 0 Elastic Behavior

f ,Y 0 Onset of Inelastic Behavior