From: Modelling of Damage Evolution in Braided Composites: Recent Developments
Failure | Criteria | Degradation |
---|---|---|
Fibre tension failure (σ 11 ≥ 0) | \( {\left(\frac{\sigma_{11}}{X_T}\right)}^2+\frac{\tau_{12}^2}{{\left({S}_f\right)}^2}+\frac{\tau_{13}^2}{{\left({S}_f\right)}^2}\ge 1 \) | E 11, E 22 , G 12 , G 23 , G 13 , υ 12 , υ 23 , υ 13degrade to 0.1 of their original value |
Fibre compression failure (σ 11 < 0) | \( {\left(\frac{\sigma_{11}}{X_C}\right)}^2+\frac{\tau_{12}^2}{{\left({S}_f\right)}^2}+\frac{\tau_{13}^2}{{\left({S}_f\right)}^2}\ge 1 \) | E 11, E 22 , G 12 , G 23 , G 13 , υ 12 , υ 23 , υ 13degrade to 0.18 of their original value |
Matrix cracking (σ 22 ≥ 0) | \( {\left(\frac{\sigma_{22}}{Y_T}\right)}^2+\frac{\tau_{12}^2}{{\left({S}_{12}\right)}^2}+\frac{\tau_{23}^2}{{\left({S}_{23}\right)}^2}\ge 1 \) | E 22 , G 12 , G 23degrade to 0.4 of their original value |
Matrix crushing (σ 22 < 0) | \( \frac{1}{4}{\left(\frac{-{\sigma}_{22}}{S_{12}}\right)}^2+\frac{Y_C^2{\sigma}_{22}}{4{S}_{12}^2{Y}_C}+\frac{\sigma_{22}}{Y_C}+\frac{\tau_{12}^2}{{\left({S}_{12}\right)}^2}\ge 1 \) | E 22 , G 12 , G 23degrade to 0.5 of their original value |
Interface delamination (σ 33 ≥ 0) | \( {\left(\frac{{{}{}^n\sigma}_{23}}{S_{123}}\right)}^2+{\left(\frac{{{}{}^{n+1}\sigma}_{23}}{S_{123}}\right)}^2+{\left(\frac{\sigma_{33}}{Z_T}\right)}^2+{\left(\frac{\sigma_{22}}{Y_T}\right)}^2\ge 1 \) | E 33, E 23 , G 13 , υ 23 , υ 13 degrade to 0 |