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Lecture No. 16. Drawing SFD and BMD. Objective:. To be able to drawn SFD and BMD using summation method. Notes To Remember When Drawing SFD and BMD. The change of shear between two points A and B is equal to the area of the loading between A and B.
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Lecture No. 16 Drawing SFD and BMD Objective: To be able to drawn SFD and BMD using summation method.
Notes To Remember When Drawing SFD and BMD • The change of shear between two points A and B is equal to the • area of the loading between A and B. • Or (The shear at point B is equal to the shear at point A + the • area of load between A and B). • The change of moment between two points A and B is equal to • the area of shear diagram between A and B. • Or (The moment at point B is equal to the moment at point A + the • area of shear between A and B). • The shear is changed by the magnitude of the concentrated load. • Upward load increase shears by its magnitude whereas downward • load decrease shears by its magnitude.
Notes To Remember When Drawing SFD and BMD • (4) Concentrated moment does not affect the value of shear but increases • moment by its magnitude if the applied moment is clockwise and • decrease moment by its magnitude if it is applied counterclockwise. • The moment is maximum wherever shear changes its sign. Both • magnitude and location of max. moment are important to be shown • on the bending moment diagram.
20N 3N/m 2N/m 40N/m 20N 3N/m 2N/m STEP (1) Reaction 40N/m 5m 2m 3m 2m 3m 16.23 18.3 8.3 8.3 Shear + 11.7 16.23 2nd. Degree curve 83.1 Moment 68 66.5 43.1 2nd. Degree curve 3rd. Degree curve 44.6 + +
Drawing V and M 9 6 6 V(x) 18N + Shear force diagram -1 4.9m M(x) 58.8N-m 54N-m Bending moment diagram + Remark: ● points of zero shear correspond to maximum moment. ● locations of zero shear and maximum moment are important to indicate on the diagram
10N 10N 2N/m A B 1m 10N 1m 1m 2m 2m 2m 4m 10N 10N-m B 10N A 10N 10N-m
10N 10N-m 20N 10N 10N 10N-m 5.67 12.33N 12.33N 2.33 S.F.D 1.2 5.67 5.67 B.M.D.
Convex 37.7 31.7 N. 31.7 – 50 = 18.3 -18.1 – 6 = 24.7 26.3 S. F. D. 26.3 convex convex 107.1 St. Line 3rd. day 65.5 64.5 N·m 13 B. M.D.