PART 2 (a) Your company is thinking of replacing a pair of cast iron gears with grade 2 through hardened steel gears. The life of the pinion is 10^9 cycles. Assuming all operating conditions stay the same, determine the most cost-effective ($/cu. ft.) option between the iron and steel gears based on AGMA contact stress analysis only. Performance between the two options should be the same. (40 points) The hardness of the cast iron gears is HB-225, Sc (350 HB) psi The cost of cast iron is ($0.075+ $0.0015*HB) per lb. The density of cast iron is 430 lbs./cu. ft. The cost of the Steel is ($0.01+$0.001*HB) per lb. The density of steel is 460 lbs./cu. ft. (b)-Complete separately from part (a). In a second instance you are told that the bending stress is too high for your gear pair to reach an appropriate safety factor for operation. State one change that you could make to your gear designs that would reduce the stress. Explain the changes and their effects on performance. You do not need to calculate anything for this question. (10 points)

4. Pulleys 1 and 2 of the rope and pulley system shown are connected and rotate as a unit. The radii of pulley 1 and 2 are 100 mm and 300 mm, respectively. Rope A is wrapped around pulley 1 and is fastened to pulley at point A'. Rope B is wrapped around pulley 2 and is fastened to pulley 2 at point B'. The rope is continuou: over pulleys 3 and 4. Determine the tension T in the rope, required to hold body W in equilibrium, if the mas of body W is 225 kg. B'A' TV C B

Analyse, using the results, how each component failed and justify how each component’s design could be improved. Figure 1   The 220mm-long bolt was used to fasten one of the engine mount to a supporting structure. In an effort to prevent the bolt from coming loose, the torque-prevailing nut and split pin were utilized to tighten the bolt. The bolt held through an aluminum housing. Due to the reduced stiffness of the fastened parts, the bolt supported a greater proportion of the applied force. The bolt's size necessitated a high tightening torque of 660 Nm (487 Lbft). Since this level of torque could not be achieved with the tools at the time, this torque was not specified. The aluminum's maximum bearing pressure was far exceeded by the bearing stress under the nut's head and face. As a result, there was excessive preload loss due to creep. fan shaft First of all, the fan shaft was required to be made of cold-drawn 1040 or 1045 steel with a yield strength of 586 MPa and the expected…