P$1$:

A double$-$edge$-$cracked member with a half$-$width $\backslash ($ b$=80\backslash$mathrm$\{$~mm$\}\backslash )$ contains equal initial cracks on each side, with a length of $\backslash ($ a$\_\{$i$\}=1\mathrm{.}1\backslash$mathrm$\{$~mm$\}\backslash )($see Figure $1).$ The member is subjected to the load history shown in Figure $2.$ Material properties for the member are presented in Table $1.$

Perform the following tasks:

$1.$ Count the number of cycles and present your results in a table.

$2.$ Using the Walker equation, calculate $\backslash (\backslash$Delta S$\_\{$q$\}\backslash )$ the equivalent zero$-$to$-$tension stress level for the entire spectrum.

$3.$ Determine the final crack length before brittle fracture occurs.

$4.$ Calculate the number of repetitions to failure.