Bending Stress A cantilever beam of length 1.1 m carries a uniformly distributed load w, as shown in Figure QI (a). The beam is made from a circular hollow section with an inner radius of R, = 50 mm and a thickness of t= 10 mm (refer to Figure Q1 (b)). The maximum allowable longitudinal stress of the beam is 150 MPa. W L Figure Q1 (a) B Figure Q1 (b) (a) Determine the reactions. (b) Draw the shear force and bending moment diagrams, indicating key values. (c) Compute second moment of area and elastic section modulus (d) Calculate the maximum permissible uniformly distributed load. (e) Draw the bending stress distribution across the section at fixed end.

Bending Stress A cantilever beam of length 1.1 m carries a uniformly distributed load w, as shown in Figure QI (a). The beam is made from a circular hollow section with an inner radius of R, = 50 mm and a thickness of t= 10 mm (refer to Figure Q1 (b)). The maximum allowable longitudinal stress of the beam is 150 MPa. W L Figure Q1 (a) B Figure Q1 (b) (a) Determine the reactions. (b) Draw the shear force and bending moment diagrams, indicating key values. (c) Compute second moment of area and elastic section modulus (d) Calculate the maximum permissible uniformly distributed load. (e) Draw the bending stress distribution across the section at fixed end.

Mechanics of Materials (MindTap Course List)

9th Edition

ISBN:9781337093347

Author:Barry J. Goodno, James M. Gere

Publisher:Barry J. Goodno, James M. Gere

Chapter6: Stresses In Beams (advanced Topics)

Section: Chapter Questions

Problem 6.8.3P: A beam of wide-flange shape, W 8 x 28, has the cross section shown in the figure. The dimensions are...

See similar textbooks

Similar questions

A cantilever beam(Z, = 6 ft) with a rectangular cross section (/> = 3.5 in., h = 12 in.) supports an upward load P = 35 kips at its free end. (a) Find the state of stress ((7T, o^., and r in ksi) on a plane-stress element at L/2 that is i/ = 8 in. up from the bottom of the beam. Find the principal normal stresses and maximum shear stress. Show these stresses on sketches of properly oriented elements. (b) Repeat part (a) if an axial compressive centroidal load N = 40 kips is added at B
A reinforced concrete T-beam (see figure) is acted on by a positive bending moment of M = 175 kip-ft. Steel reinforcement consists of four bars of 1.41-inch diameter. The modulus of elasticity for the concrete is Ec= 3000 ksi while that of the steel is £s = 29,000 ksi. Let b = 48 im, rf = 4 in., bw=15 in,, and d = 24 in, Find the maximum stresses in steel and concrete, If allowable stresses for concrete and steel are o"ac = 1400 psi and tr^ =18 ksi, respectively, what is the maximum permissible positive bending moment?
A singly symmetric beam with a T-section (see figure) has cross-sectional dimensions b = 140 mm, a = 190, 8 mm, b. = 6,99 mm, and fc = 11,2 mm. Calculate the plastic modulus Z and the shape factor.
A steel beam of length L = 16 in. and cross-sectional dimensions h = 0.6 in. and h = 2 in. (see figure) supports a uniform load of intensity if = 240 lb/in., which includes the weight of the beam. Calculate the shear stresses in the beam (at the cross section of maximum shear force) at points located 1/4 in., 1/2 in., 3/4 in., and I in, from the top surface of the beam. From these calculations, plot a graph showing the distribution of shear stresses from top to bottom of the beam.
A simple beam of span length 3.2 m carries a uniform load of intensity 48 kN/m, The cross section of the beam is a hollow box with wood flanges and steel side plates, as shown in the figure. The wood flanges are 75 mm x 100 mm in cross section, and the steel plates are 300 mm deep. What is the required thickness t of the steel plates if the allowable stresses are 120 M Pa for the steel and 6,5 M Pa for the wood? (Assume that the moduli of elasticity for the steel and wood are 210 GPa and 10 GPa, respectively, and disregard the weight of the beam.)
A W 310 x 52 steel beam is subjected to a point load P = 45 kN and a transverse load V = 20 kN at B. The beam has length L =2m.(a) Calculate the principal normal stresses and the maximum shear stress on element D located on the web right below the top flange and near the fixed support. Neglect the weight of the beam, (b) Repeat Part a atcentroid C (sec figure). See Table F-l(b), Appendix F, for beam properties
The cantilever beam AB shown in the figure is an S6 × 12.5 steel I-beam with E = 30 × 106 psi. The simple beam DE is a wood beam 4 in. x 12 in. (nominal dimensions) in cross section with E = 1.5 x 106 psi. A steel rod AC of diameter 0.25 in., length 10 ft, and E = 30 x 106 psi serves as a hanger joining the two beams. The hanger fits snugly between the beams before the uniform load is applied to beam DE. Determine the tensile force Fin the hanger and the maximum bending moments MABand MDEin the two beams due to the uniform load, which has an intensity q = 400 lb/ft. Hint: To aid in obtaining the maximum bending moment in beam DE, draw the shear-force and bending-moment diagrams.
Each girder of the lift bridge (sec figure) is 180 ft long and simply supported at the ends. The design load for each girder is a uniform load of intensity 1,6 kips/ft. The girders are fabricated by welding three steel plates to form an I-shaped cross section (see figure) having section modulus S = 3600 in3. What is the maximum bending stress rmaxin a girder due to the uniform load?
A foot bridge on a hiking trail is constructed using two timber logs each having a diameter d = 0.5 m (see figure a). The bridge is simply supported and has a length L = 4 m. The top of each log is trimmed to form the walking surface (see Fig, b)LA simplified model of the bridge is shown in Fig. g. Each log must carry its own weight w = 1.2 kN/m and the weight (P = 850 N) of a person at mid-span, (see Fig. b). Determine the maximum tensile and compressive stresses in the beam (Fig, b) due to bending. If load h is unchanged, find the maximum permissible value of load ... if the allowable normal stress in tension and compression is 2.5 M Pa.
A thin, high-strength steel rule (E = 30 x 10ft psi) having a thickness t = 0.175 in. and length L = 48 in. is bent by couples Mcinto a circular arc subtending a central angle a = 40° (sec figure), What is the maximum bending stress emax. in the rule? By what percent docs the stress increase or decrease if the central angle is increased by 10%? What percent increase or decrease in rule thickness will result in the maximum stress reaching the allowable value of 42 ksi?
A simple beam thai is IS ft long supports a uni¬form load of intensity a. The beam is constructed of two angle sections, each L (1 × 4 × 1/2, on either side of a 2 in. x 8 in. (actual dimensions! wood beam (see the cross section shown in the figure part a]. The modulus of elasticity of the s I eel is 10 limes that of the wood, (a) If the allowable stresses in the steel and wood are 12,000 psi and 900 psi. respectively, what is the allow atile load a t. A olc. Disregard the weight of the beam, and see Table F-5(a) of Appendix I ' for I lie dimensions and properties of the angles. (b) Repeal partial if a I in. 10 in. wood Hange tactual dimensions) is added i see figure pallhi b).
A beam with a guided support and 10-ft span supports a distributed load of intensity q = 660 lb/ft over its first half (see figure part a) and a moment Mq = 300 ft-lb at joint B. The beam consists of a wood member (nominal dimensions 6 in. x 12 in. and actual dimensions 5.5 in. x 11.5 in. in cross section, as shown in the figure part b) that is reinforced by 0.25-in.-thick steel plates on top and bottom. The moduli of elasticity for the steel and wood are £s = 30 X 106 psi and £"w = 1.5 X 106 psi, respectively. Calculate the maximum bending stresses trs in the steel plates and rw in the wood member due to the applied loads. If the allowable bending stress in the steel plates is = 14,000 psi and that in the wood is (T.dV!= 900 psi, find qmiiX. (Assume that the moment at .fi, A/0, remains at 300 ft-lb.) If q = 660 lb/ft and allowable stress values in part (b) apply, what is Müm^ at B?