In a typical center cracked beam:

$\backslash$table$[[$Load$,$K$,$Geometrical Poperties$],[N,$Mpa'm$^^0\mathrm{.}5,$W $($cm$),7,62],[-5,6241059,0,002476831,S(cm),30,48],[-6,5435638,0,002881756,B(cm),5,08],[-6,5435638,0,002881756,E(MPa),200000],[-6,0838351,0,002679293,,],[-7,0032916,0,003084218,,],[-8,085728,0,003591766,,],[-6,5435638,0,002881756,,],[-7,0032916,0,003084218,,],[-6,5435638,0,002881756,,],[-2,8657362,0,001262057,,],[-2,4060078,0,001059595,,],[-2,8657362,0,001262057,,],[-808,5728,0,356091766,,]]$

Calculate Eracture Toughness for $a=2,3,4$ and $5mm$ yalues.