Holooly Plus Logo

Question 7.1: Design of a Nondestructive Test A large steel plate used in ......

Design of a Nondestructive Test
A large steel plate used in a nuclear reactor has a plane strain fracture toughness of 80,000 psi \sqrt{in.} and is exposed to a stress of 45,000 psi during service. Design a testing or inspection procedure capable of detecting a crack at the edge of the plate before the crack is likely to grow at a catastrophic rate.

The 'Blue Check Mark' means that this solution was answered by an expert.
Learn more on how do we answer questions.

We need to determine the minimum size of a crack that will propagate in the steel under these conditions. From Equation 7-1 assuming that f = 1.12 for a single-edge notch crack:

K=f \sigma \sqrt{\pi a}      (7-1)
K_{Ic}=f \sigma \sqrt{\pi a}
80,000 \ psi \ \sqrt{in.}=(1.12)(45,000 \ psi) \sqrt{\pi a}
a= 0.8 \ in.

A 0.8 in. deep crack on the edge should be relatively easy to detect. Often, cracks of this size can be observed visually. A variety of other tests, such as dye penetrant inspection, magnetic particle inspection, and eddy current inspection, also detect cracks much smaller than this. If the growth rate of a crack is slow and inspection is performed on a regular basis, a crack should be discovered long before reaching this critical size.

Related Answered Questions