A structural component in the form of a wide plate is to be

A structural component in the form of a wide plate is to be fabricated from a steel alloy that has a plane strain fracture toughness of 98.9 MPa Squareroot m (90 ksi Squareroot in.) and a yield strength of 860 MPa (125,000 psi). The flaw size resolution limit of the flaw detection apparatus is 3.0 mm (0.12 in.). If the design stress is one-half of the yield strength and the value of Y is 1.0, determine whether or not a critical flaw for this plate is subject to detection.

Solution

This problem asks that we determine whether or not a critical flaw in a wide plate is subject to detection given the limit of the flaw detection apparatus (3.0 mm), the value of KIc (98.9 MPa m ), the design stress (y/2 in which y = 860 MPa), and Y = 1.0. We first need to compute the value of a_c

s_{design max} = ½ s = 860/2 = 430 MPa

K_Ic = 98.9 MPam

a_min = 3 mm

a_c = 1/p(98.9/430)² = 0.0168 m or 16.8 mm >> 3 mm

Thus the flaw would be detectable.