On a bend specimen a single$-$specimen Jc test is performed. Using a non$-$destructive technique

crack initiation is observed at a load $P=9315N.$ During the test the load is recorded as a

function of the load$-$point displacement $V.$ A polynomial fit of the $P-V$ curve resulted in:

$v={10}^{-5}P+{10}^{-14}{P}^4.$ where $V$ is expressed in mm and $P$ in N $.$

The work done $U$ is given by the expression:

$U={\displaystyle \underset{\phantom{}}{\overset{\phantom{}}{}}}PdV$

Given: width $W=50mm$; crack length $a=12mm$; thickness $B=28mm$ and the

flow stress ${}_{ys}=1000$MPa. Determine Jc and check against the ASTM test validity criteria.

$B,(W-a)>10(\frac{J}{{}_{ys}})$