Problem #1 (50 pts): An 8' long simply supported beam is subjected to a varying load at its center with maximum/minimum load of 50kips/10kips respectively. The beam has a rectangular cross section with a width of 2" and height of 8" made of a material with Ultimate Strength (S.) of 100Ksi. a) Does this design have infinite fatigue life using Modified Goodman criteria? b) If it doesn't last for infinite cycles under the above criteria, determine its estimated life? [Note: For fatigue, consider f=0.75, a Surface factor (Ka) of 0.6 and all other factors of 1.0] Problem #2 (75 points): A 20"OD disk is shrunk-fit onto another disk, both made of A517-Grade F steel, with an OD of 18" and an ID of 10" with a shrink-fit of 0.020". The outside disk has a longitudinal (radial) crack on its outside surface of 0.3" deep. Material of both disks is typical carbon-steel with Young's modulus of 30*10 psi and Poisson's ratio of 0.3. Their fracture toughness varies with temperature as shown. The assembly's temperature is being lowered to subfreezing levels during operation. Determine at what temperature the outside disk will break? FRACTURE TOUGHNESS, Kesi 150 135 o 1/2-INCH-THICK SPECIMENS 010-INCH-THICK SPECIMENS A 20-INCH-THICK SPECIMENS B04 FOR 2-INCH-THICK SPECIMEN B-0.4 FOR 1-INCH THICK SPECIME 08.04 FOR 1/2-INCH-THICK SPECIMEN -350 -300 -200 -150 TEMPERATURE,F -100 -50 +50