4-1. Based upon ASTM E399, Standard Test Method for Plane-Strain Fracture Toughness of Metallic Materials, the stress intensity factor, Kl, for the widely used compact specimen (the depth of the notch is 0.2W ) is KI=(BW1/2P)f(a/W) where f(a/W) is given as f(a/W)=(1a/W)3/2(2+a/W)(0.866+4.64a/W)13.32a2/W2+14.72a3/W35.6a4/W4 Plot the ratio of KI/(P/BW1/2) for values of a/W between 0.25 and 0.75. 4-2. KI for a center-cracked panel is given as KI=aseca/W For the same B, compare the loads required to attain the same value of KI for a compact specimen (W=50mm(1.97in),.a/W=0.5) and a center-cracked panel (W=200mm(7.87 in. ),a/W=0.25)