Acenter-cracked plate is loaded in tension and has dimensions of b = 40 mm, t = 5 mm, and large h, and it contains an initial crack of length 2ai = 8 mm. a zero-to-maximum cyclic load of 80 kn is applied, and the material has σy= 320 mpa, kic= 40 mpa√m.

(a)what is the crack length for plastic yielding, ay?

(b)what is the crack length for brittle fracture, ac?

(c) will the plate fail by

i. plastic yielding before fatigue crack growth,

ii. plastic yielding after fatigue crack growth,

iii. brittle fracture before fatigue crack growth, or

iv. brittle fracture after fatigue crack growth?

briefly explain why.