(Solved): help compute on excel Design the shaft shown in Figures 12-1 and 12-2. It is to be machined from SA ...

Design the shaft shown in Figures 12-1 and 12-2. It is to be machined from SAE 1144 OQT 1000 steel. The shaft is part of the drive for a large blower system supplying air to a furnace. Gear $A$ receives $200\mathrm{hp}$ from gear $P$. Gear $C$ delivers the power to gear $Q$. The shaft rotates at $600\mathrm{rpm}$. Use $D_A=20.00$ in, and $D_C=10.00$ in, Pressure angle $=\varphi =20^{\circ }$ tion First determine the properties of the steel for the shaft. From Figure A4-2, $sy=83000psi$, $s_v=118000$ psi, and the percent elongation is $19\%$. Thus, the material has good ductility. Using Figure 5-8, we can estimate $s_n=42.000$ psi. For reversed bending, let $K_m=K_{st}=1.0$. A size factor should be applied to the endurance strength because the shaft will be quite large to be able to carry $200\mathrm{hp}$. Although we do not know the actual size at this time, we might select $C_s=0.75$ from Figure $5-9$ as an estimate. A reliability factor should also be specified. This is a design decision. For this problem, let's design for a reliability of 0.99 and use $C_R=0.81$. Now we can compute the estimated actual endurance strength: $s_n^{\prime }=s_n{C}_1{C}_R=(42000)(0.75)(0.81)=25500\text{ psi }$ The design factor is taken to be $N=2$. The blower is not expected to present any unusual shock or impact. Now we can compute the torque in the shaft from Equation (12-1): $T=63000(P)/n=63000(200)/600=21000\mathrm{lb}\cdot \text{ in }$ Note that only that part of the shaft from $A$ to $C$ is subjected to this torque. There is zero torque from the right of gear $C$ over to bearing $D$. See Figure $12-11$ (d). Forces on the Gears: Figure 12-11 shows the two pairs of gears with the forces acting on gears A and $C$ shown. Observe that gear $A$ is driven by gear $P$, and gear $C$ drives gear $Q$. It is very important