Concept explainers
A moveable steel stand supports an automobile engine weighing W = 750 lb, as shown in the figure part a. The stand is constructed of 2.5 in. x 2.5 in. x 1/8 in.-thick steel tubing. Once in position, the stand is restrained by pin supports at B and C. Of interest are stresses at point A at the base of the vertical post; point A has coordinates (x = 1.25, y = 0, z = 1.25) in inches. Neglect the weight of the stand.
(a) Initially, the engine weight acts in the — z direction through point Q, which has coordinates (24, 0, 1.25) inches. Find the maximum tensile, compressive, and shear stresses at point A.
(b) Repeat part (a) assuming now that, during repair, the engine is rotated about its own longitudinal axis (which is parallel to the x axis) so that Warts through Q [with coordinates (24, 6, 1.25) in inches] and force F = 200 lb is applied parallel to the y axis at distance d = 30 in
Trending nowThis is a popular solution!
Chapter 8 Solutions
Mechanics of Materials (MindTap Course List)
- A long re Lai nine: wall is braced by wood shores set at an angle of 30° and supported by concrete thrust blocks, as shown in the first part of the figure. The shores are evenly spaced at 3 m apart. For analysis purposes, the wall and shores are idealized as shown in the second part of the figure. Note that the base of the wall and both ends of the shores are assumed to be pinned. The pressure of the soil against the wall is assumed to be triangularly distributed, and the resultant force acting on a 3-meter length of the walls is F = 190 kN. If each shore has a 150 mm X 150 mm square cross section, what is the compressive stressarrow_forwardThe stresses acting on element B on the web of a train rail (see figure part a of Problem 7.2-5) arc found to be 5700 psi in compression in the horizontal direction and 2300 psi in compression in the vertical direction (see figure). Also, shear stresses of magnitude 2500 psi act in the directions shown. Determine the stresses acting on an element oriented at a counterclockwise angle of 50° from the horizontal. Show these stresses on a sketch of an element oriented at this angle.arrow_forwardSolve the preceding problem if the mass of the tailgate is MT— 11 kg and that of the crate is hic— 6S kg. Use dimensions H = 305 mm, L = 406 mm, dc= 460 mm, and dT= 350 mm. The cable cross-sectional area is At= 11.0 mm'. (a) Find the tensile Force T and normal stress T in each cable. (b) IF each cable elongatesarrow_forward
- A double-decker bicycle rack made up of square steel tubing is fixed at A (figure a). The weight of a bicycle is represented as a point load applied at B on a plane frame model of the rack (figure b). (a)Find the state of plane stress on an element C located on the surface at the left side of the vertical tube at the base A. Include the weight of the framing system. (Assume weight density y = 77 kN/m .) (b) Find the maximum shear stresses on an element at C and show them on a sketch of a properly oriented element. Assume that element C is a sufficient distance from support A so that stress concentration effects are negligiblearrow_forwardA bracket ABCD having a hollow circular cross section consists of a vertical arm AB{L = 6 ft), a horizontal arm BC parallel to the v0 axis, and a horizontal arm CD parallel to the -0 axis (see figure). The arms BC and CD have lengths b}= 3.6 ft and b2= 2,2 ft, respectively. The outer and inner diameters of the bracket are d-, = 7,5 in. and dx= 6,8 in. An inclined load P = 2200 lb acts at point D along line DH. Determine the maximum tensile, compressive, and shear stresses in the vertical armarrow_forwardA semicircular bar AB lying in a horizontal plane is supported at B (sec figure part a). The bar has a centerline radius R and weight q per unit of length (total weight of the bar equals TiqR). The cross section of the bar is circular with diameter d. (a) Obtain formulas for the maximum tensile stress v maximum compressive stress c, and maximum in-plane shear stress rmdX at the top of the bar at the support due to the weight of the bar. (b) Repeat part (a) if the bar is a quarter-circular segment (see figure part b) but has the same total weight as the semicircular bar.arrow_forward
- ,3-23 A 200-lb trap door (AD) is supported by a strut (BC) which is pin connected to the door at B (see figure). (a) Find reactions at supports A and C. (b) Find internal stress resultants N, V, and M on the trap door at 20 in. from A.arrow_forwardThree identical circular disks A, B, and Care welded to the ends of three identical solid circular bars (see figure). The bars lie in a common plane and the disks lie in planes perpendicular to the axes of the bars. The bars arc welded at their intersection D to form a rigid connection. Each bar has diameter d1= 0.5 in. and each disk has diameter d2= 3.0 in. Forces P1, P2, and P3act on disks A, B, and C, respectively, thus subjecting the bars to torsion. If P1= 28 lb, what is the maximum shear stress in any of the three bars?arrow_forwardA single steel strut AB with a diameter (a) Find the strut force Fs and average normal stress ds= 8 mm supports the vehicle engine hood of a in the strut. mass 20 kg that pivots about hinges at C and D (see (b) Find the average shear stress t aver in the bolt at A,figure parts a and b). The strut is bent into a loop at (C) Find the average bearing stress bon the bolt at A. its end and then attached to a bolt at A with a diameter db= 10 mm. Strut AB lies in a vertical plane.arrow_forward
- The roof over a concourse at an airport is supported by the use of pretensioned cables. At a typical joint in the roof structure, a strut AB is compressed by the action of tensile forces Fin a cable that makes an angle = 75° with the strut (see figure and photo). The strut is a circular tube of steel (E = 30,000 ksi) with outer diameter d2= 2.5 in. and inner diameter d1= 2.0 in. The strut is 5.75 ft long and is assumed to be pin-connected at both ends. Using a factor of safety n = 2.5 with respect to the critical load, determine the allowable force F in the cable.arrow_forwardA post AB supporting equipment in a laboratory is tapered uniformly throughout its height H (see figure). The cross sections of the post are square, with dimensions b × b at the top and 1.5b × 1.5b at the base. Derive a formula For the shortening 8 of the post due to the compressive load P acting at the top. (Assume that the angle of taper is small and disregard the weight of the post itself.)arrow_forwardA plumber's valve wrench is used to replace valves in plumbing fixtures. A simplified model of the wrench (see figure part a) consists of pipe AB (length L. outer diameter D inner diameter dy), which is fixed at A and has holes of a diameter dhon either side of the pipe at B. A solid, cylindrical bar CBD (lengths, diameter^) is inserted into the holes at B and only one force F = 55 lb is applied in the -Z direction at C to loosen the fixture valve at A (see figure part c). Let G = 11,800 ksi, v = 0.30, L = 4 in., a = 4.5 in., d2= 1.25 in., dx= 1 in., and dh= 0.25 in. Find the state of plane stress on the top of the pipe near A (at coordinates A" = 0,Y = Q,Z = d->12), and show all stresses on a plane stress element (see figure part b). Compute the principal stresses and maximum shear stress, and show them on properly rotated stress elementsarrow_forward
- Mechanics of Materials (MindTap Course List)Mechanical EngineeringISBN:9781337093347Author:Barry J. Goodno, James M. GerePublisher:Cengage Learning