flexural stress

Problem 509
A section used in aircraft is constructed of tubes connected by thin webs as shown in Fig. P-509. Each tube has a cross-sectional area of 0.20 in². If the average stress in the tubes is no to exceed 10 ksi, determine the total uniformly distributed load that can be supported in a simple span 12 ft long. Neglect the effect of the webs.
 

Problem 508
Determine the minimum height h of the beam shown in Fig. P-508 if the flexural stress is not to exceed 20 MPa.
 

Problem 507
In a laboratory test of a beam loaded by end couples, the fibers at layer AB in Fig. P-507 are found to increase 60 × 10^-3 mm whereas those at CD decrease 100 × 10^-3 mm in the 200-mm-gage length. Using E = 70 GPa, determine the flexural stress in the top and bottom fibers.
 

Problem 506
A flat steel bar, 1 inch wide by ¼ inch thick and 40 inches long, is bent by couples applied at the ends so that the midpoint deflection is 1.0 inch. Compute the stress in the bar and the magnitude of the couples. Use E = 29 × 10⁶ psi.
 

Problem 503
A cantilever beam, 50 mm wide by 150 mm high and 6 m long, carries a load that varies uniformly from zero at the free end to 1000 N/m at the wall. (a) Compute the magnitude and location of the maximum flexural stress. (b) Determine the type and magnitude of the stress in a fiber 20 mm from the top of the beam at a section 2 m from the free end.