Puck “c” criterion

II.1.10.19 Puck “c” criterion

Sometimes, an additional term is given in the expression corresponding to the fiber failure and the modified version of Puck criterion is defined as follows:

F I^{Puck_c} = \max (|\frac{σ_{11}}{σ_{11}^{all}}|, {(\frac{σ_{11}}{2 σ_{11}^{t,all}})}^{2} + \frac{σ_{22}^{2}}{σ_{22}^{c,all} σ_{22}^{t,all}} + {(\frac{τ_{12}}{τ_{12}^{all}})}^{2} + σ_{22} (\frac{1}{σ_{22}^{t,all}} - \frac{1}{σ_{22}^{c,all}})) .

Ply passes the failure criterion if the two following conditions are satisfied

|σ_{11}| \leq σ_{11}^{all},

{(\frac{σ_{11}}{2 σ_{11}^{t,all}})}^{2} + \frac{σ_{22}^{2}}{σ_{22}^{c,all} σ_{22}^{t,all}} + {(\frac{τ_{12}}{τ_{12}^{all}})}^{2} + σ_{22} (\frac{1}{σ_{22}^{t,all}} - \frac{1}{σ_{22}^{c,all}}) \leq 1 .

The calculation of reserve factor is done as for version “b” of Puck criterion, but one uses a modified expression for $a$ parameter:

a = {(\frac{σ_{11}}{2 σ_{11}^{t,all}})}^{2} + \frac{σ_{22}^{2}}{σ_{22}^{c,all} σ_{22}^{t,all}} + {(\frac{τ_{12}}{τ_{12}^{all}})}^{2} .

This criterion is referred to as “Puck_c” criterion in FeResPost.

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