Question

15 KN 6 km 100 m NA -- B D 100 m 2. (30pts.) For the truss system shown, a. (10 pts) Draw the shear and moment diagrams for the rectangular wooden beam shown. b. (6 pts)Determine the magnitude of the absolute maximum moment ( M.) and its location c. (7pts) Find the maximum bending stress in the member (O) d. (7 pts Compute the Banding Stress at a point on the section that is 25 mm below the top of the beam O. 2m 120 mm 10 m TR14N Rg 19 KN

Answer 1

15 KN 100 mm 6kN/m A* E N- B D 100mm - 1 .RA= 14 KN Ro 19 KN 0.8m * 7 리 2m 1m 120 mm

calculation of shear force (SF): SF at A= RA 14 KN. 9.2 KN SF at B = 14 - 6x0.8 SF at I just left) = 14 - 6+2 2 2 KN, SF at D (Just right) 2-15 = -13 kW. SF at - 19 KN -13- 6*1 =

Shear force diagram: 14 9.2 (+) 2 13 19 Bending moment calculation. Bm at A = 0. BM at Ez 0 Bm at B N. RAX 0.8 - 6x0.8. 0.8 2 14x0.8 - 6x 0.82 2 9.28 kNom.

BM at D- RAx2 - 6x2 - 2 2 2 14x2 - 6 x 2 x 1 16. KN- m. Bm diagram: 16 koom 9.28 t + B D (b the above momeart bending Referring diagram, Absolute maximum BM = 16 kN-m. maxion um Bm Location of is point 'D' which is at a distance of 2 m from support A. stress Comax): Maximum bending Bending stress is maximum where bending moment is maximum.

will be present at point D. Now, Mmas Oman = y. I where, bxh? 12 120x(2 x 100) 12 12 1 = 80 x 106 mme y = Extre me fibre distance from the neutral axis loo mm. N 16x 10 106 max 2 x 10o 80x106 Iman 20 N/mm² Ans, 1 25mm My B 1 9.28x106 80 x 106 (100-25) Section at B B = 8.7 N/mm2 Ans.