Question

The cross section is rectangular with a base of 5 in. and height of 8 in. A force of P 17 kip is acting on the beam. 4.5 ft 4.5 ft Part A Determine the absolute maximum bending stress in the beam, assuming that the support at B exerts a uniformly distributed reaction on the beam Express your answer to three significant figures and include appropriate units | σmax = 1 Value Units

Answer 1

+ 9 sigma m_a = 0 (w _b times 3) (9+ 3/2) -(17 times 4.5) = 0 w_b = 2.4286 kip/ft + up arrow sigma f_y = 0 r_a + (w_b times 3) -17 = 0 r_a = 9.7143 kip share force: at point A v_a = 9.7143 kip at point C v_c = 9.7143 kip (before C) v_c = 9.7143 -17 = -67,2857 (after c) at point D v_d = -7.2857 kip at point B v_b = 0 (before b) bending moment: at point c m_c = 43.7143 kip- ft at point d m_d = 10.9286 kip- ft m_max = 43.7143 sigma _max = m_y/I = (43.7143) (12) (8/2)/ 5 times 8^3 /12 = 9.8357 ksi