A pressure vessel support bracket is to be designed so that it can withstand a tensile loading cycle of $0500$ MPa once every day for $25$ years.

Determine which of the following steels would have a greater tolerance to intrinsic defects

in this application:

$($a$)$ Meraging steel $($KIC $=82$ MN$/($m$)^-3/2,$ C $=0\mathrm{.}15$ x $(10)^-11,$ m $=4\mathrm{.}1)$

$($b$)$ A medium strength steel $($KIC $=50$ MN$/($m$)^-3/2,$ C $=0\mathrm{.}24$ x $(10)^-11,$ m $=3\mathrm{.}3)$