Question

2.The shaft shown in the figure is driven by a gear at the right keyways, drive a fan at eh left keyways, and supported by two deep grove ball bearings. The shaft is made of AISI 1020 cold- drawn steel. At steady state speed, the gear transmits a radial load of 230 Ibf and a tangential load of 633 Ibf at pitch diameter of 8 inch. Determine fatigue factor of safety at any potentially critical locations using the DE-Gerber failure criterion. a. b. Check the deflection safety as suggested minimums for bearing and gears. 1287 8 50 0.20- + 0485 1.750 2.20 2.75 2.0 0,75 1.181 1.70 R. R. 4.1 R 0.15 R. heyway 3. A 1- inch diameter solid round bar has a grove of 0.1-inch-deep with a 0.1 in radius machined into it. The bar is made of AISI 1020 CD steel and is subjected to a purely reversing torque of 1800 lbf.in. For the S-N Curve of this material, let f 0.9 Estimate the number of cycles to failure. If the bar is also placed in an environment with temperature of 750 F, estimate the number of cycles to failure. a. b.

Answer 1

5) 6 98 65)168) Se = (2.70) (68) ka= It: e532)(%) )2.9 km 12 9

d1.75m 0.035in Frem tado ,kが3 0 66 08 = 0.72 = 0.828 0.30 p S0 883 ( 828) (32 : S 252 m S A td s 5 252) 8) = 3.59

20· 55 =0.065 »,-175%ss-1-13 1 0.76 = O. 839 Seニ0.883 (o. 839) lay) = 252 ktsi 4.122 π ()-553)125.2 -0107o 848 - o. 3 3(2 535) +

れ e. Stijut dliam We cu aia 2 2 20 the men.。 A-