Mechanical Engineering Design 3rd. Edition by Ansel C. Ugural | 9780367513474 | 0367513471

Mechanical Engineering Design

3 SOLVED PROBLEMS

173 SOLVED PROBLEMS

Question: 7.CS.1

Camshaft Fatigue Design of Intermittent-Motion Mechanism Figure 7.16 illustrates a rotating camshaft of an intermittent-motion mechanism in its peak lift position. The cam exerts a force P on the follower, because of a stop mechanism (not shown), only during less than half a shaft revolution. ...

Verified Answer:

See Figures 7.16 and 7.17. Alternating and mean st...

Question: 11.4

Analysis of a Planetary Gear Train In the epicyclic gear train illustrated in Figure 11.11, the sun gear is driven clockwise at 60 rpm and has N1 teeth, the planet gear N3 teeth, and the ring gear N4 teeth. The sun gear is the input and the arm is the output. The ring gear is held stationary. What ...

Verified Answer:

Refer to Figure 11.11. The gear value, through the...

Question: 4.1

Analysis of a Duplex Structure A steel rod of cross-sectional area As and modulus of elasticity Es has been placed inside a copper tube of cross-sectional area Ac and modulus of elasticity Ec (Figure 4.1a). Determine the axial shortening of this system of two members, sometimes called an isotropic ...

Verified Answer:

The forces produced in the rod and in the tube are...

Question: 9.6

Critical Speed of a Stepped Shaft Figure 9.9(a) shows a stepped round shaft supported by two bearings and carrying the flywheel weight W. Calculate the critical speed in rpm. Given: The moment of inertia (2I) of the shaft in its central region is twice that of the moment of inertia (I) in the end ...

Verified Answer:

The application of the moment-area method (Section...

Question: 9.3

Shaft Design for Repeated Torsion and Bending Power is transmitted from a motor through a gear at E to pulleys at D and C of a revolving solid shaft AB with ground surface. Figure 9.5(a) shows the corresponding load diagram of the shaft. The shaft is mounted on bearings at the ends A and B. ...

Verified Answer:

The reactions at

A

and

B ...

Question: 8.3

Ball Bearing Load Capacity A single-row ball bearing supports a radial load F as shown in Figure 8.11a. Calculate: a. The maximum pressure at the contact point between the outer race and a ball. b. The factor of safety, if the ultimate strength is the maximum usable stress. Given: F=1.2 kN, E=200 ...

Verified Answer:

See Figure 8.11a and Table 8.5. For the situation ...

Question: 12.1

Geometric Quantities for Helical Gears Two helical gears have a center distance of c=10 in., width b=1.9 in., a pressure angle of ϕ=25°, a helix angle of ψ=30°, and a diametral pitch of P=6 in.^−1. If the speed ratio is to be rs=1/3, calculate: a. The (transverse) circular, normal circular, and ...

Verified Answer:

a. Applying Equations (12.1) and (12.2),

p...

Question: 11.3

Contact Ratio of Meshing Gear and Pinion A gear set has N1 tooth pinion, N2 tooth gear, pressure angle Φ, and diametral pitch P (Figure 11.7). Find: a. The contact ratio. b. The pressure angle and contact ratio, if the center distance is increased by 0.2 in. Given: N1=15, N2=45, Φ=20°, P=2.5 in.^−1 ...

Verified Answer:

Applying Equation (11.2), the pitch diameter for t...

Question: 1.2

Camshaft Torque Requirement A rotating camshaft (Figure 1.6) of an intermittent motion mechanism moves the follower in a direction at right angles to the cam axis. For the position shown, the follower is being moved upward by the lobe of the cam with a force F. A rotation of θ corresponds to a ...

Verified Answer:

The work done on the camshaft equals the work done...

Question: 17.CS.3

Stress Concentration in a Plate with a Hole in Uniaxial Tension A thin plate containing a small circular hole of radius a is subjected to uniform tensile load of intensity σ0 at its edges, as shown in Figure 17.16(a). Apply the FEA to determine the theoretical stress-concentration factor. Given: ...

Verified Answer:

Owing to the symmetry, only any one-quarter of the...

Question: 17.CS.1

Analysis and Design of a Truss A three-bar truss 123 (Figure 17.6(a)) is subjected to a horizontal force P acting at joint 2. Analyze the truss and calculate the required cross-sectional area of each member. Assumptions: All members will have the same yield strength Sy, length L, and axial rigidity ...

Verified Answer:

The reactions are noted in Figure 17.6(a). The nod...

Question: 12.CS.1

High-Speed Turbine Geared to Drive a Generator A turbine rotates at about n=8000 rpm and drives, by means of a helical gearset, a 250 kW (335 hp) generator at 1000 rpm, as depicted in Figure 12.8. Determine: a. The gear dimensions and the gear tooth forces. b. The load capacity based on the bending ...

Verified Answer:

See Figures 12.6 and 12.8 and Tables 11.5 through ...

Question: 9.4

Factor of Safety for a Stepped Shaft under Torsional Shock Loading A stepped shaft of diameters D and d with a shoulder fillet radius r has been machined from AISI 1095 annealed steel and fixed at end A (Figure 9.6). Determine the factor of safety n, using the maximum shear stress theory ...

Verified Answer:

From the geometry of the shaft,

D=2d [/lat...