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

Reciprocatin compressor - , Reciprocatin Compressor. It is taken in use to...

Reciprocatin Compressor. It is taken in use to compressor gases. ( kE 2  - kE 1) = 0, ( pE 2  - pE 1) = 0 q 1-2  - w 1-2 = ( h 2  - h 1 ) + 0 + 0 - q 1-2  - (- w

Advantages of casting process, Advantages of Casting Process: Electri...

Advantages of Casting Process: Electric Furnace : The melting of steel by electric furnaces developed rapidly for the availability of cheap electric power. Electricity is us

Determine the service and backwash rates, Service duty point: 3 m3/h Backw...

Service duty point: 3 m3/h Backwash duty point: 9 m3/h Part (a) What is the speed of the pump to achieve the service and backwash flow rates ? Part (b) What would be the best

Motion of the boat, Motion of the boat:  (i) A man having weighs 500 N...

Motion of the boat:  (i) A man having weighs 500 N and is in a boat weighing 1500 N which is free to move over a steady lake. If he begins running along the length of the boat

Explain caustic stress corrosion cracking, Q. Explain caustic Stress Corros...

Q. Explain caustic Stress Corrosion Cracking? Dilution of the caustic prior to injection into a relatively hot stream will minimize the potential of caustic Stress Corrosion Cr

Different types of layouts, List and explain four different types of layout...

List and explain four different types of layouts for a factory.

Indian standard (is 812-1957)-welding definition, As per Indian standard (I...

As per Indian standard (IS 812-1957) Define weld as "a union between two pieces of a metal at faces rendered plastic or liquid by heat or by pressure or both filler metal may b

Determine for water flow rate, A counter flow heat exchanger is used to coo...

A counter flow heat exchanger is used to cool 2000kg/hr of oil(Cp= 2.5 KJ/Kg K) from 105 o C to 30 o C by the use of water entering at 15 o C. If the overall heat transfer coeff

Zenner diode fundamentals of electricity , Zenner Diode: Zenner diode is ...

Zenner Diode: Zenner diode is generally used as a voltage regulator. When voltage falls below the predetermined value, zenner diode functions in the same way as an ordinary diode

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