Answer Happy

can you show work on the required questions? and support answers please
A customer (Rouge Steel) has approached us about some "forensic engineering." Given your recent exposure to this customer's products through your design work, I thought you might be able to address some of the issues raised here. Rouge Steel has had several types of crane hook failures in the last few months. In a recent failure, fracture took place in a wholly brittle manner, occurring transversely through the back of the hook as shown in Fig. 1, this being a plane where the tensile stress due to bending is the maximum (as we well know!). The dimensions of the hook corresponded closely to those given in B.S. 482, the proportions of the trapezoidal section giving a cross-sectional area in excess of the requirements for the specification (see Fig. 2). The fracture surface shown in Fig. 3 was essentially flat and crystalline in appearance with evidence of shear lips only at the peripheries. A highly significant feature was the presence of a crescent-shaped area at the inner surface measuring 0.500 x 0.187 in as indicated by the arrow in Fig. 3. Further detailed examination of the surface revealed four, fine, transverse fissures in approximately the same vertical plane as the fracture and situated 0.75 in to 2.50 in above it (see arrows in Fig. 1). Microstructural analysis of the area adjacent to the crescent of the fracture surface revealed it to be decarburized and containing globules of oxide and slag, clearly manufacturing-related and not service- related features. Specifics of the crane hook are as follows: The hook was a low carbon steel in the normalized condition. Sections from the hook gave a yield strength of 49,000 psi and an ultimate tensile strength of 64,380 psi with %el of 34. The material appeared to be notch sensitive as Charpy impact tests revealed impact energy at room temperature to be in the range of 32.5 to 72 ft-lb. In your analysis consider the effect of the crescent fissure as a crack in a notch sensitive material. If fracture is assumed to have occurred at a working load of 15 tons, calculate if brittle fracture from the crack-like feature is reasonable at the sharp corner (you will need to find/estimate a value for the fracture toughness of the material). Finally, based on your knowledge of fracture: a) recommend remedial action to prevent fracture in other hooks of the same design and material and b) redesign the hook/material to eliminate failures of this sort.
FRACTURE BEND TEST SPLEMEMSA CUT HARDNESS SURVEY MICROSCOPIC FARMINATION ORILLINGS FOR ANALYSIS 6T.P: DIAMETER AT BOTTOM OF THPEACH 2-286 SECTION LOOKING IN DIRECTION OF ARROW 6 SEND TEST SPECIMENS 5 Figure 2 Dimensions in hook 10% 131%22
Figure 1 Fracture and position of fissures
Figure 3 Appearance of fracture surface showing defect at origin