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

Strength of materials, sir/madam, i would like to teach online how can i ha...

sir/madam, i would like to teach online how can i have to proceed

Identification of pressure welds, Q. Identification of Pressure Welds? ...

Q. Identification of Pressure Welds? Pressure welds shall be identified as follows: a. Generally each weld shall be stamped adjacent to the weld with the welder's identity c

Compute the ratio of the torque, Compute the ratio of the torque: Comp...

Compute the ratio of the torque: Compute the ratio of the torque transmitted by a hollow & a solid shaft of the similar material, length & weight. Solution d i = inte

Show space considerations for plant, Q. Show Space Considerations for plant...

Q. Show Space Considerations for plant? There are particular spacing constraints which need particular care and attention when optimizing the layout area utilization in both ne

Explain system and parting sand, Q. Explain System and Parting sand? S...

Q. Explain System and Parting sand? System Sand: In mechanized foundries, where machine moulding is employed a so called "system sand" is used to fill the whole flask. Since

THERMAL, HOW HEAT TRANSFER TAKES PLACE

HOW HEAT TRANSFER TAKES PLACE

The parts and design of the pocket amp, The problem: - Deaf blind peop...

The problem: - Deaf blind people have a huge problem when crossing the streets. They always need assistance from a sighted person or a trained dog to cross the street. There i

Design storage compounds for bulk solids, Q. Design Storage compounds for b...

Q. Design Storage compounds for bulk solids? Storage compounds for bulk solids, liquids and liquefied gases are normally included in a plant layout to provide short term storag

Pneumatic circuit, fully automatic pnuematic cicuit explanation#Minimum 100...

fully automatic pnuematic cicuit explanation#Minimum 100 words accepted#

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