(15 points) Bending members, as in Fig. 8.13(a), of depth b = 50 mm, thickneiscsetit;els seiv mm, and large h are made of 18-Ni maraging steel (vacuum melted). In • bending moment may be as high as M = 3.5 kINI•m, and members with edge cracks larger than a = 1.0 mm are normally found in inspection and scrapped. Determine: a. The safety factor on stress for the brittle fracture situation, Xx. b. The crack length that will cause brittle fracture. Use the expression for any a with exact F (Fig. 8.13(a)) to determine the crack length by brittle fracture. a, Acceptable methods to obtain this crack length are iterative hand calculations, MS Excel iterative or “Goal Seek” methods, and MATLAB (or other computational software) “while loop” iterations. Approximate values of F to critical crack length are not acceptable. c. The safety factor on crack length (brittle fracture), Xa. d. The safety factor against fully plastic yielding, X. e. The crack length causing failure by fully plastic yielding, ao. 1. The safety factor on crack length at fully plastic yielding, (we’ll call it X,,’ ). (g —1). Determine items “g” through “I”, and label your answers as such according to the following: Assume that some of these members were accidentally not inspected and found their way into actual service with cracks as large as a = 5.0 mm. Replacement is expensive. Assume that you are the engineer who must make the decision on replacement What would you decide? Support your decision with analysis “a” through “r above (these will be items “g” through “I”) for the new crack length. m. Compare the overall governing safety factor for crack lengths of 1 mm to the one for crack lengths of 5 mm.