7.2 Degraded Strength

\includegraphics[width=\textwidth ]{./Images/Degraded.png}

Introducing a damage factor $d_ f$=0.8 on the Degraded Material page allows CADEC to compute the load multiplier at which all laminas fail, called Last Ply Failure (LPF). In this case LPF=214.8, with the fiber failure mode shown by the icon for the 0 deg laminas.

The huge value of R for the 90 deg laminas is caused by the fact that those laminas were degraded to ($1-d_ f$) of their original moduli, as explained in the textbook.

The Degraded Material page borrows the value of FPF from the Intact Material page so that the designer has all the information right here at your fingertips.

Quiz: how come the value here is FPF=121.4 while on the previous figure it was FPF=38.34 ?

Answer: in the previous figure, we forgot to check in-situ. Wow! and improvement of 217% ? Yes, it is possible.