FEA is an excellent tool for consideration of when tensile cracking is likely
to occur in metal forming operations or in technological tests. FEM programs are
able to compute the distribution of both the largest principal stress and the effective
strain inside the volume of the workpiece. Moreover, the combined effect of
the two is also computed by the software, in terms of the damage parameter itself,as defined by the expression on the left-hand side of eq. 9-1 or, alternatively, the
damage parameter normalized with respect to stress, as given by eq. 9-2. The region
inside the workpiece that attains the highest damage parameter will be the region
most likely to crack. If cracking does take place in accordance with the Cockcroft–
Latham criterion, a crack will form when the damage parameter reaches the critical
value of C1 (or C
1) for the actual material of the workpiece.
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