A 1/4 -in drill rod was heat-treated and ground. The measured hardness was found to be 490 Brinell. Estimate the endurance strength if the rod is
Estimate S′e for the following materials:
(a) AISI 1020 CD steel.
(b) AISI 1080 HR steel.
(c) 2024 T3 aluminum.
(d) AISI 4340 steel
Estimate the fatigue strength of a rotating-beam specimen made of AISI 1020 hot-rolled steel corresponding to a life of 12.5 kilocycles of stress
Derive Eq. (6–17). For the specimen of Prob. 6–3, estimate the strength corresponding to 500 cycles.
For the interval 103 ≤ N ≤ 106 cycles, develop an expression for the axial fatigue strength (S′f ) ax for the polished specimens of
Estimate the endurance strength of a 32-mm-diameter rod of AISI 1035 steel having a machined finish and heat-treated to a tensile strength of 710 MPa.
Two steels are being considered for manufacture of as-forged connecting rods. One is AISI 4340 Cr-Mo-Ni steel capable of being heat-treated to a
A solid round bar, 25 mm in diameter, has a groove 2.5-mm deep with a 2.5-mm radius machined into it. The bar is made of AISI 1018 CD steel and is
A solid square rod is cantilevered at one end. The rod is 0.8 m long and supports a completely reversing transverse load at the other end of ±1 kN.
A rectangular bar is cut from an AISI 1018 cold-drawn steel flat. The bar is 60 mm wide by
10 mm thick and has a 12-mm hole drilled through the
Bearing reactions R1 and R2 are exerted on the shaft shown in the figure, which rotates at
1150 rev/min and supports a 10-kip bending force. Use a
A bar of steel has the minimum properties Se = 276 MPa, Sy = 413 MPa, and Sut = 551 MPa.
The bar is subjected to a steady torsional stress of 103
Repeat Prob. 6–12 but with a steady torsional stress of 138 MPa and an alternating bending stress of 69 MPa.
Repeat Prob. 6–12 but with a steady torsional stress of 103 MPa, an alternating torsional stress of 69 MPa, and an alternating bending stress of 83
Repeat Prob. 6–12 but with an alternating torsional stress of 207 MPa.
Repeat Prob. 6–12 but with an alternating torsional stress of 103 MPa and a steady bending stress of 103 MPa.
The cold-drawn AISI 1018 steel bar shown in the figure is subjected to an axial load fluctuating between 800 and 3000 lbf. Estimate the factors of
Repeat Prob. 6–17, with the load fluctuating between .800 and 3000 lbf. Assume no buckling.
Repeat Prob. 6–17, with the load fluctuating between 800 and -3000 lbf. Assume no buckling.
The figure shows a formed round-wire cantilever spring subjected to a varying force. The hardness tests made on 25 springs gave a minimum hardness of
The figure is a drawing of a 3- by 18-mm latching spring. A preload is obtained during assembly by shimming under the bolts to obtain an estimated
Repeat Prob. 6–21, part b, using the modified Goodman criterion.
The figure shows the free-body diagram of a connecting-link portion having stress concentration at three sections. The dimensions are r = 0.25 in, d
The torsional coupling in the figure is composed of a curved beam of square cross section that is welded to an input shaft and output plate. A torque
Repeat Prob. 6–24 ignoring curvature effects on the bending stress.
In the figure shown, shaft A, made of AISI 1010 hot-rolled steel, is welded to a fixed support and is subjected to loading by equal and opposite
A schematic of a clutch-testing machine is shown. The steel shaft rotates at a constant speed ω. An axial load is applied to the shaft and is
For the clutch of Prob. 6–27, the external load P is cycled between 20 kN and 80 kN. Assuming that the shaft is rotating synchronous with the
A flat leaf spring has fluctuating stress of σmax = 420 MPa and σmin = 140 MPa applied for 5 (104) cycles. If the load changes to σmax
A machine part will be cycled at ±48 kpsi for 4 (103) cycles. Then the loading will be changed to ±38 kpsi for 6 (104) cycles. Finally, the load
A rotating-beam specimen with an endurance limit of 50 kpsi and an ultimate strength of 100 kpsi is cycled 20 percent of the time at 70 kpsi, 50
Solve Prob. 6–1 if the ultimate strength of production pieces is found to be Sut = 245LN (1, 0.0508) kpsi.
The situation is similar to that of Prob. 6–10 wherein the imposed completely reversed axial load Fa = 15 LN (1, 0.20) kN is to be carried by the
A solid round steel bar is machined to a diameter of 1.25 in. A groove 1/8 in deep with a radius of 1/8 in is cut into the bar. The material has a
Repeat Prob. 6–34, with a completely reversed torsional moment of T = 1400 lbf • in applied.
A 5/4 -in-diameter hot-rolled steel bar has a 1/8 -in diameter hole drilled transversely through it. The bar is nonrotating and is subject to a
Repeat Prob. 6–36, with the bar subject to a completely reversed torsional moment of 2400 lbf • in.
The plan view of a link is the same as in Prob. 6–23; however, the forces F are completely reversed, the reliability goal is 0.998, and the
A 1/4 by 3/2 -in steel bar has a 3/4 -in drilled hole located in the center, much as is shown in Table A–15–1. The bar is subjected to a
From your experience with Prob. 6–39 and Ex. 6–19, you observed that for completely reversed axial and bending fatigue, it is possible to
A shaft is loaded in bending and torsion such that Ma = 600 lbf • in, Ta = 400 lbf • in, Mm =
500 lbf • in, and Tm = 300 lbf • in. For the
The section of shaft shown in the figure is to be designed to approximate relative sizes of
d = 0.75D and r = D/20 with diameter d conforming to
The rotating solid steel shaft is simply supported by bearings at points B and C and is driven by a gear (not shown) which meshes with the spur gear
A geared industrial roll shown in the figure is driven at 300 rev/min by a force F acting on a 3-in-diameter pitch circle as shown. The roll exerts a
The figure shows a proposed design for the industrial roll shaft of Prob. 7–4. Hydrodynamic film bearings are to be used. All surfaces are machined
In the double-reduction gear train shown, shaft a is driven by a motor attached by a flexible coupling attached to the overhang. The motor provides a
In the figure is a proposed shaft design to be used for the input shaft a in Prob. 7–7. A ball bearing is planned for the left bearing, and a
An AISI 1020 cold-drawn steel shaft with the geometry shown in the figure carries a transverse load of 7 kN and a torque of 107 N • m. Examine the
A 1-in-diameter uniform steel shaft is 24 in long between bearings.
(a) Find the lowest critical speed of the shaft.
(b) If the goal is to
Demonstrate how rapidly Rayleigh’s method converges for the uniform-diameter solid shaft of
Prob. 7–14, by partitioning the shaft into first
Compare Eq. (7–27) for the angular frequency of a two-disk shaft with Eq. (7–28), and note that the constants in the two equations are
For a uniform-diameter shaft, does hollowing the shaft increase or decrease the critical speed?
The shaft shown in the figure carries a 20-lbf gear on the left and a 35-lbf gear on the right.
Estimate the first critical speed due to the loads,
A transverse drilled and reamed hole can be used in a solid shaft to hold a pin that locates and holds a mechanical element, such as the hub of a
A guide pin is required to align the assembly of a two-part fixture. The nominal size of the pin is 15 mm. Make the dimensional decisions for a 15-mm
An interference fit of a cast-iron hub of a gear on a steel shaft is required. Make the dimensional decisions for a 45-mm basic size medium drive fit.
A pin is required for forming a linkage pivot. Find the dimensions required for a 50-mm basic size pin and clevis with a sliding fit.
A journal bearing and bushing need to be described. The nominal size is 1 in. What dimensions are needed for a 1-in basic size with a close running
A gear and shaft with nominal diameter of 1.5 in are to be assembled with a medium drive fit, as specified in Table 7–9. The gear has a hub, with
An uncrowned straight-bevel pinion has 20 teeth, a diametral pitch of 6 teeth/in, and a transmission accuracy number of 6. Both the pinion and gear
For the gearset and conditions of Prob. 15–1, find the power rating based on the AGMA surface durability.
An uncrowned straight-bevel pinion has 30 teeth, a diametral pitch of 6, and a transmission accuracy number of 6. The driven gear has 60 teeth. Both
For the gearset and conditions of Prob. 15–3, find the power rating based on AGMA surface durability. For the solutions to Probs. 15–3 and
An uncrowned straight-bevel pinion has 22 teeth, a module of 4 mm, and a transmission accuracy number of 5. The pinion and the gear are made of
For the gearset and conditions of Prob. 15–5, find the power rating for AGMA bending strength.
In straight-bevel gearing, there are some analogs to Eqs. (14–44) and (14–45). If we have a pinion core with a hardness of (HB) 11 and we try
Refer to your solution to Probs. 15–1 and 15–2, which is to have a pinion core hardness of 300 Brinell. Use the relations from Prob. 15–7 to
Repeat Probs. 15–1 and 15–2 with the hardness protocol
A catalog of stock bevel gears lists a power rating of 5.2 hp at 1200 rev/min pinion speed for a straight-bevel gearset consisting of a 20-tooth
Apply the relations of Prob. 15–7 to Ex. 15–1 and find the Brinell case hardness of the gears for equal allowable load Wt in bending and wear.
Use your experience with Prob. 15–11 and Ex. 15–2 to design an interactive computer-aided design program for straight-steel bevel gears,
A single-threaded steel worm rotates at 1725 rev/min, meshing with a 56-tooth worm gear transmitting 1 hp to the output shaft. The pitch diameter of
As in Ex. 15–4, design a cylindrical worm-gear mesh to connect a squirrel-cage induction motor to a liquid agitator. The motor speed is 1125
The figure shows an internal rim-type brake having an inside rim diameter of 12 in and a dimension
R = 5 in. The shoes have a face width of 1 ½ in
For the brake in Prob. 16–1, consider the pin and actuator locations to be the same. However, instead of 120°, let the friction surface of the
In the figure for Prob. 16–1, the inside rim diameter is 280 mm and the dimension R is 90 mm. The shoes have a face width of 30 mm. Find the
The figure shows a 400-mm-diameter brake drum with four internally expanding shoes. Each of the hinge pins A and B supports a pair of shoes. The
The block-type hand brake shown in the figure has a face width of 30 mm and a mean coefficient of friction of 0.25. For an estimated actuating force
Suppose the standard deviation of the coefficient of friction in Prob. 16–5 is = 0.025, where the deviation from the mean is due entirely to
The brake shown in the figure has a coefficient of friction of 0.30, a face width of 2 in, and a limiting shoe lining pressure of 150 psi. Find the
Refer to the symmetrical pivoted external brake shoe of Fig. 16–12 and Eq. (16–15). Suppose the pressure distribution was uniform, that is, the
The shoes on the brake depicted in the figure subtend a 90◦ arc on the drum of this external pivoted-shoe brake. The actuation force P is
Problem 16–9 is preliminary to analyzing the brake. A molded lining is used dry in the brake of Prob. 16–9 on a cast iron drum. The shoes are 7.5
The maximum band interface pressure on the brake shown in the figure is 90 psi. Use a 14-indiameter drum, a band width of 4 in, a coefficient of
The drum for the band brake in Prob. 16–11 is 300 mm in diameter. The band selected has a mean coefficient of friction of 0.28 and a width of 80
The brake shown in the figure has a coefficient of friction of 0.30 and is to operate using a maximum force F of 400 N. If the band width is 50 mm,
The figure depicts a band brake whose drum rotates counterclockwise at 200 rev/min. The drum diameter is 16 in and the band lining 3 in wide. The
The figure shows a band brake designed to prevent “backward” rotation of the shaft. The angle of wrap is 270◦, the band width is 2 1/8 in,
A plate clutch has a single pair of mating friction surfaces 300 mm OD by 225 mm ID. The mean value of the coefficient of friction is 0.25, and the
A hydraulically operated multidisk plate clutch has an effective disk outer diameter of 6.5 in and an inner diameter of 4 in. The coefficient of
Look again at Prob. 16–17.
(a) Show how the optimal diameter d∗ is related to the outside diameter D.
(b) What is the optimal inner
A cone clutch has D = 330 mm, d = 306 mm, a cone length of 60 mm, and a coefficient of friction of 0.26. A torque of 200 N ?m is to be transmitted.
Show that for the caliper brake the T / (f F D) versus d / D plots are the same as Eqs.
(b) and (c) of Sec. 16–5.
A two-jaw clutch has the dimensions shown in the figure and is made of ductile steel. The clutch has been designed to transmit 2 kW at 500 rev/min.
A brake has a normal braking torque of 320 N m and heat-dissipating surfaces whose mass is 18 kg. Suppose a load is brought to rest in 8.3 s from an
A cast-iron flywheel has a rim whose OD is 60 in and whose ID is 56 in. The flywheel weight is to be such that an energy fluctuation of 5000 ft ?lbf
A single-geared blanking press has a stroke of 8 in and a rated capacity of 35 tons. A cam-driven ram is assumed to be capable of delivering the full
Using the data of Table 16–6, find the mean output torque and flywheel inertia required for a three-cylinder in-line engine corresponding to a
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