Answers to Selectecj Problems
Given here are the answers to problems for which there are unique solutions. Many of the problems for solution in this book are true design problems, and individual design decisions are required to arrive at the solutions. Others are ofthe review question form tor which the answers arc in the text ofthe associated chapter It should also be noted that some ofthe problems require the selection ot design factors and the use of data from charts and graphs. Because of the judgment and interpolation required, some ofthe answers may be slightly different from your solutions.
CHAPTER 1 The Nature of Mechanical Design
15. D - 44.5 mm 16. Z. = 14.0 m 17. T= 14l8N-m 18. M = 2658 mm19. S = 2.43 X 10'mm' 20. / = 3.66 X 10'mm" 21. Z. 2 X 2 X 3/8 22. P = 5.59 kW 23. .v„ = 876 MPa 24. Weight = 48.9 N 25. T= 20.3 N-m H = 0.611 rad Scale = 5.14 1b-in/deg Scale = 33.3 N-m/rad 26 Energy = 1.03 x 10" Ib-ft/yr Energy = 3.88 X lO'W-h/yr 27 M = 540 Ib • s/ftp = 25.9 X lO'N-s/m4.60 X 10' rev
24. AISI 12L13 steel has lead added to improve machinability. 25. AISI 1045, 4140, 4640, 5150. 6150, 8650. 26. AISI 1045. 4140. 4340, 4640, 5150, 6150, 8650. 27. Wear resi.stance, strength, ductility. AISI 1080. 28. AISI 5160 OQT 1000 is a chromium steel, having nominally 0.80 percent chromium and 0.60 percent carbon, a high carbon alloy steel. It has fairly high strength and good ductility. It was through-hardened, quenched in oil, and tempered at 1000°F. 29. Yes. with careful specitlcadon ofthe quenching medium. A hardness of HRC 40 is equivalent to HB 375. Appendix 3 indicates that oil quenching would not produce an adequate hardness. However, Appendix 4-1 shows that a hardness of HB 400 could be obtained by quenching in water and tempering in 700°F while still having 207f elongation for gciod ductility. 33. AISI 200 and 300 series 34. Chromium 35. ASTM A992 structural steel 37. Gray iron, ductile iron, malleable iron 41. Stamping