Statics Design Project

Third Design Project

University of Wisconsin - Madison

Abstract

For this design project I was required to design a shaft for a water turbine that must deliver power to an electric generator and also to a bucket elevator for carrying grain to a hopper while meeting the criteria given to me by my boss. I was given some initial values and am supposed to place two bearings B and D to support the shaft to meet the criteria given.

Design Criteria

Shown below is the diagram I was given to find the placement of bearings B and D. I was given that the total bending load on the shaft at the sprocket C is 815 lb, and the driven side of the chain is oriented at an angle of 40 deg from the vertical. At gear E, Which drives the generator, the bending forces on the shaft are 494lb in the y-direction, and 180lb in the x-direction. Also the flat belt pulley A which drives the elevator, the maximum allowable tension in the belt is 417lb. The belt will be parallel on either side of the pulley, and oriented at an angel of 60 deg. from the horizontal. The coefficient of static friction between the belt and the pulley is .35. The bending load exerted by the pulley is equal to the sum of the tensions on either side of the pulley. When solving, draw the shear and bending moment diagrams for the x and y direction. The bending moment and any point will then be equal to sqrt (Mh ^2 + Mv62). The bending moments at the two bearings was not to exceed 3500lb-in. and the bending moment at C was not to exceed 5000lb-in.

Design Solution and Conclusion

To solve I set up my knowns in section A of the appendix using the equation to find t1 I solved and found T1 to be 138.87lb. Then I added T1 and T2 together to find T total which was 555.87lb. From finding this I was able to then find Ay which was 481.41 lb and Ax that was 227.9lb (Section B) Then I also solved for Cx which was 523.87lb and Cy which was 624.33lb. Using lengths of 6 for distances of my bearings from c I then drew separate diagrams for x and y (section c) Then in Section D of the appendix I solved for the moments about By and Bx and found Dy = 188.13lb and Dx = 393lb using those values I solved for the equilibrium of The forces in the x and