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

Use of stainless steels in welding, Q. Use of Stainless Steels in welding? ...

Q. Use of Stainless Steels in welding? Considerable care must be exercised to obtain sound, crack-free welds. These difficulties are pronounced when welding very high-chromium

Evaluate the angle of heel, A motor cycle with rider, weight of 250 Kg., th...

A motor cycle with rider, weight of 250 Kg., the centre of Gravity of the machine and rider combined being 60 cm above from ground level when the machine is standing upright. Each

Automated material handling, Automated Material Handling We have dealt...

Automated Material Handling We have dealt along with the automated guided vehicles and Robots utilized in the industry. Because of the industrial automation, various changes h

Computer aided synthesis, The basic aim of synthesis in design process is t...

The basic aim of synthesis in design process is to provide information which can tell you how to improve the design. In general the synthesis process gives many alternatives of

Fuels and lubrication technology, minimum mass of air required for complete...

minimum mass of air required for complete combustion of the HFO

Excessive pedal pressure required motorcycle problem, If Excessive Pedal Pr...

If Excessive Pedal Pressure Required Causes of Problem Remedy Incorrect shoe placement Improper anchor pin position l

Advantages-disadvantages of transparent polymeric, (a) List several advanta...

(a) List several advantages and disadvantages of using transparent polymeric materials for eyeglass lenses. (b) Cite four properties (in addition to being transparent) that are

Draw the bending moment diagram and shear force diagram, Draw the bending m...

Draw the bending moment diagram and shear force diagram: A cantilever beam of 8 m length is subjected to point loads of 15 kN, 10 kN, 25 kN and 20 kN at distances of 4 m, 2 m,

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