Question

Problems for Figures P11-77 to P11-84 Each Figure shows a mechanical device in which one or more forces are applied parallel to and away from the axis of the main, beam-like part. The devices are supported by bearings at the locations marked with an X, which can provide reaction forces in any direction per pendicular to the axis of the beam. One of the bearings has the capa bility of resisting horizontally directed forces. For each figure the objectives are 1. Break the compound beam into parts consisting of each of the straight components. 2. Show the complete free body diagram of each component part including all external loads and internal forces and bend ing moments required to keep the part in equilibrium. 3. For the main, horizontal part only, draw the complete shear- ing force and bending moment diagrams. Refer to Section 11-10 for examples. 11-84 - (5) points 180 lb 20 - 16 in 35 in 14 in 16 in 125 lb 16 in FIGURE P11-84

Answer 1

+18016 2010 67 in 16in 712516 200 COTA 2. Free body diagram 180 lb 200 MBTB 3511 THB 16" 1 Eu 4 Fx 161 Me Fu (3) 7125lb 201

MB and Mc represents the bending moments at Band C. By, Ey, fy and cy represent vertical forces and Be, Ex and Cox represent horizontal forces acting internally to keep the structure in equilibrium. Ey , Fy and I are reactions at bearings. 3. From FBDC) , Efx=0: Bx = 125 x cos2o=117.46 lb Ifyzo By = 125 x singo=42.75 lb in EM=0: My = 125 cos20x16" = 1879.39 lb.in = - 1879.39 lb ft 18 12 = 156.6 lb-ft From FBD (3), Ifx=0 x = 180xc0 520=169.14 lb Ifyo Cy = 180 sinzo = 61.56 lb <M=0 : Me = 18000S 20 x4 – 197.34 lb-fb 121 Now FBD(2) becomes, 197.34 lb-ft 156.6 lbft - 169.14 lb 117.4616 4 161 Į 36" 4 fra 16" to 42.7516 Ey Fy 61.56 lb Take moment about E: F4 X 35 +61-56x(35+6) +197.34+156.6–42.76X16 6 X 16 2 = 0 Fy=191.51 eb 12 {fu=0: Eu +F4 + 42.75 +61.5620 Ey = 191.51 - 42.15-61.5 63 87.216 EFx = 0: For = 117.46-169.14=-51.68 lb

156.61 b. FL AB 16" 117.4616 197.34 lb ft < 169.14 lb 51-68 TF 16" PE 351 87.2 lb 42.75lb 191.51 lb 61.56 lb Shear force dicigram 129.95 42.75 B -61.56 -61.56 Bending moment Diagram 279.4 197.346.ft- 99,6 156.6