Question

How to determine the direction of Bending moment ? SIN A ASAN SIEN VMB) E MB)=0 Met 5x4m = 0 My = - Zoom Oy MB-5X4m = 0 Um - why? Mg = 20 kv.m (22. What's the relationship of Moment direction with the

Answer 1

Bending moments are generally tarcen o sagging abending moment as the togging bending moment as we 4 sogging bending moment creates compression on Aber and tension at bottom where as Hogging benang moment creates tension eat koster top and compress at bottom. a 5km 5 KN 4)_5 KN TO calculate the value m. Mo, we use the moment eruilbricim wuation at Point R C EMAO mo 5KM Lo sum Emo - means aulth authonetic xok clock coise moments anticlock corse moment must equal to and zero > Notation: * clock urse moment about point is taken as the, and Autie clock wrist moment about point Al is takes as-ve. Re] +MB+ (5*4)=0 dock lise mes -20 km assumed the mo is clock wise But we get he value of mB; that mean's our assumed direction is wrong.

* Actually mp must be in anti dock wise direction o correct direction of moment me as shown below 5KM 15KN 5KM mp= 20 kN-m X 5KM - um Staa © Bueltion of moment will be depend on the direction of force (A to). © if the direction of the vertical forces acting on. beam changes then the direction of movement will changes 5KM Emaco MB um ky now -584+MB=0 [MB= 20) (MB-720 KN-m/ (now the direction of MB es clock urise)