Machine Elements in Mechanical Design, 6th edition Robert L Mott Test Bank

Instructor’s Manual and Test Bank

For

MACHINE ELEMENTS IN MECHANICAL DESIGN Sixth Edition

Robert L. Mott, University of Dayton Edward M. Vavrek, Purdue University Jyhwen Wang, Texas A&M University

Table of Contents Chapter 1 The Nature of Mechanical Design

1

Chapter 2 Materials in Mechanical Design

3

Chapter 3 Stress and Deformation Analysis

11

Chapter 4 Combined Stresses and Stress Transformations

50

Chapter 5 Design for Different Types of Loading

121

Chapter 6 Columns

158

Chapter 7 Belt Drives, Chain Drives and Wire Rope

178

Chapter 8 Kinematics of Gears

193

Chapter 9 Spur Gear Design

225

Chapter 10 Helical Gears, Bevel Gears and Wormgearing

275

Chapter 11 Keys, Couplings, and Seals

311

Chapter 12 Shaft Design

316

Chapter 13 Tolerances and Fits

354

Chapter 14 Rolling Contact Bearings

360

Chapter 16 Plain Surface Bearings

365

Chapter 17 Linear Motion Elements

372

Chapter 18 Springs

377

Chapter 19 Fasteners

396

Chapter 20 Machine Frames, Bolted Connections and Welded Joints

398

Chapter 21 Electric Motors and Controls

407

Chapter 22 Motion Control: Clutches and Brakes

411

iii

CHAPTER 1 THE NATURE OF MECHANICAL DESIGN Problems 1‐14 require the specification of functions and design requirements for design projects and have no unique solutions. 15.

D

1.75 in  25.4 mm/in

44.5 mm

16.

L

46.0 m  0.3048 m/ft

14.0 m

17.

T

12 500 lbin  0.1130 Nm/lbin

18.

A

4.12 in2  645.2 mm2/in2

19.

Section modulus

20.

Moment of inertia

21.

Given: Amin

S I

1418 Nm

2658 mm2

14.8 in3  1.639104 mm3/in3

2.43105 mm3

88.0 in4  4.162105 mm4/in4

3.66107 mm4

750 mm2: In U.S. units; Amin

1.162 in2

U.S. Angle – From Appendix 15‐1: L223/8; A

1.36 in2 890 mm2

SI Angle – From Appendix 15‐3: Angle 75755; A

P

7.5 hp  745.7 W/hp

22.

Power

23.

Ultimate tensile strength su

24.

Given: Steel shaft; D

35 mm

Volume

0.035 m; L

V

area  length

 0.035 m 2/4  0.675 m

Mass Weight

876 MPa 0.675 m

9.81 m/s2

7680 kg/m3 From Appendix 3

D2/4  L 6.4910‐4 m3

7680 kg/m3  6.4910‐4 m3

mg

675 mm

mass  g ; g

density  volume; Density of steel

V

5.59 kW

127 ksi  6.895 MPa/ksi

Find: Weight of the shaft: Weight Mass

5.59103 W

864 mm2

4.98 kg

4.98 kg  9.81 m/s2

48.9 kgm/s2

1

48.9 N

25.

Given: For a torsional spring, Torque Find the scale of the spring

180 lbin for 35 of rotation.

Torque per unit of rotation. Express the result in both

U.S. and SI units.

T

180 lbin  0.1130 Nm/lbin

Angle

26.

20.3 Nm

35   rad/180

0.611 radians 5.14 lbin/degree

Scale

T/

180 lbin/35

Scale

T/

20.3 Nm/0.611 rad

33.3 Nm/rad

Given: 12.5 hp motor operating 16 h/day, 5 days/week Compute the energy, E, used by the motor for one year in both U.S. and SI units.

27.

E

12.5 hp  16h/day  5 days/wk  52 wks/year  550 ftlb/s/hp  3600 s/h

E

1.031011 ftlb/year

E

1.031011 ftlb/year  1.356 J/ftlb  1.0 Nm/J  1.0 W/Nm/s  1h/3600 s

E

38.8106 Wh/year

Given: Viscosity 

28.



38.8 MWh/year

3.75 reyn  1.0 lbs/in2 /reyn  144 in2/ft2

3.5 lbs/in2  4.448 N/lb  1.0 in2/645.2 mm2  106 mm2/m2

Given: n

540 lbs/ft2 25.9103 Ns/m2

1750 rpm; 24h/day; 5.0 years. Find life in number of revolutions.

Life

1750 rev/min  24 h/day  60 min/h 365 days/year  5 years

Life

4.60109 revolutions

2

From Eq. 2-5:

3