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

Compute the utilization of peak capacity, Compute the utilization of peak c...

Compute the utilization of peak capacity: If the fabrication department of the engine manufacturer, operated under ideal conditions, produces 100 engines per day. Management b

Design standards - planning a new airport , Design Standards: The fol...

Design Standards: The following design standards for a modern airport facility catering to latest models of aircraft may be noted for guidance.

Shear force and bending moment of simply supported beam., #questicalculatio...

#questicalculation of shear fon\rce and bending moment..

Wire-frame entities-representing ellipse and parabolas, wire-frame entities...

wire-frame entities-representing ellipse and parabolas

Force on string - mechanics, Force on String: A string ABCD , attach...

Force on String: A string ABCD , attached to the two fixed points A and D has two weight of 1000N each attached to it at points B and C . The weights rest with portio

Usage of special tool, USAGE OF SPECIAL TOOL: The common tools used in rep...

USAGE OF SPECIAL TOOL: The common tools used in repair and maintenance of motorcycles were introduced to you in previous sections. Now, we shall learn about some special tools and

Gyroscope, what is principle of gyroscope

what is principle of gyroscope

Determine the reactions at beam, Determine the reactions at bea: A can...

Determine the reactions at bea: A cantilever AB, 1.8 m long is fixed at A and carries uniformly distributed load of 20 kN/m over its entire length and a point load of 30 kN at

Hydrostatic pressure, can a swimming pool that is full be cracked or lifted...

can a swimming pool that is full be cracked or lifted by hydrostatic pressure?

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