Shear forces and bending moments, Mechanical Engineering

Assignment Help:

Shear Forces and Bending Moments:

  • A beam is a structural member, subjected to a system of external forces (involving inclined load) to generate the bending of the member in an axial plane.
  • At the cross-section of the beam the shear force is explained as the unbalanced vertical force either to the right or to the left of the section.
  • The bending moment at cross section of the beam is explained as the algebraic sum of moments of all of the forces acting on the beam either to the right or to the left of the section.
  • All of the upward forces to the left of the section and all of the downward forces to the right of section cause positive shear force. All of the downward forces to the left of the section & all of the upward forces to the right of the section cause negative shear force.
  • The BM is called to be positive, while it is acting in an anticlockwise direction to the left of the section and clockwise direction to the right of the section. The BM is called to be negative, while it is acting in clockwise direction to the left of the section & an anticlockwise direction to the right of the section.
  • Whereas drawing SF and BM diagrams, all of the positive values are plotted above the base line & the negative values below it.
  • The maximum BM takes place, where the SF is zero or changes sign.
  • If the SF diagram line is horizontal among two points, the BM diagram is inclined. It denoted there is no load among two points. If the SF diagram is inclined among two points, the BM diagram is a parabola of second degree. It denotes that there is a uniformly distributed load among the two points. If the SF diagram is in the form of parabola of second degree among two points, the BM diagram is in the form of parabola of third degree (cubic parabola). It denote that there is a uniformly varying load among the two points.
  • The point of contraflexure is a point whereas the BM is zero or changes sign.
  • If a beam is subjected to a couple, the SF does not modify. But the bending moment suddenly changes in magnitude equivalent to that of the couple.
  • If there is a point load or reaction, the BM does not alter at that point. But the SF suddenly modifies (either decreases or increases) in magnitude equivalent to that of point load or support reaction.
  • If a beam is subjected to inclined loads, their components at right angles to the axis of components (vertical components) shall cause shear force & bending moment and their components along the axis of the beam (horizontal components) shall cause axial force or thrust in the beam.
  • Whereas drawing axial forces diagram, tensile forces are taken as positive & compressive forces are taken as -ve.

 


Related Discussions:- Shear forces and bending moments

Energy accelerated, Ask question EMC#Minimum 100 words accepted#

Ask question EMC#Minimum 100 words accepted#

Communication, is effective commucation an intergral aspect in the mecheni...

is effective commucation an intergral aspect in the mechenical engineering field?

Procedure for calculating the wind force on vessels, Q. Procedure for calcu...

Q. Procedure for calculating the wind force on vessels? The National Building Code of Canada has a similar procedure for calculating the wind force on vessels as ASCE. The bas

Determine the work done and change in thermal energy, (a) Show that for an ...

(a) Show that for an adiabatic process Pv r = C, holds good. (b) One Kg of a contain gas is at 0.11 KPa and 15 o C. It is compressed until its volume a 0.1m 3 . if the compress

Mr, I need rewording

I need rewording

Plate clutch lifter bolts for even tightening, Plate clutch lifter bolts fo...

Plate clutch lifter bolts for even tightening : Reset clutch assembly using plate lifter clutch alignment tool.

What do you mean by moulding materials, Q. What do you mean by Moulding mat...

Q. What do you mean by Moulding materials? Various types of materials are used in the foundries for the manufacture of casting moulds and cores. These materials are divided in

Explain sulphidation process, Q. Explain Sulphidation process? The pres...

Q. Explain Sulphidation process? The presence of sulphur converts the surface of the metal to a sulphide scale which is generally more destructive than an oxide scale. Sulphid

Repair of surface defects in welds, Repair of surface defects in welds by c...

Repair of surface defects in welds by chipping, grinding and gouging is permitted provided the thickness is not reduced below the minimum required. Removal of defects shall be ver

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd