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

Frictional force acting on the ladder, Frictional force acting on the ladde...

Frictional force acting on the ladder: A uniform ladder having length 13m and weighing 250N is placed against smooth vertical wall with its lower end 5m from wall. The coeffi

Dimension commands-autocad, Dimension Commands: For example, the illust...

Dimension Commands: For example, the illustration above shows two different dimension styles. The one on the left is the default style known as STANDARD. If you do not create a

Pin shift return spring-gear complaints, pin shift return spring : Check p...

pin shift return spring : Check pin shift return spring for proper torque.

Evaluate the chebyshev spacing for a function, Evaluate the chebyshev Spaci...

Evaluate the chebyshev Spacing for a function y = 2 x 2 - x for the range 0 ≤ x ≤ 2 where four precision point are required. For these precision points, determine φ 2 , φ 3 , φ 4

Explain about nonconforming material, Q. Explain about Nonconforming Materi...

Q. Explain about Nonconforming Material? If PMI test results indicate that the material or item does not meet the specified composition of the alloy, the subject material/item

Find the outer and inner diameters of frictional surface, A single plate cl...

A single plate clutch, effective on both sides is needed to transmit 25 KW at 3000 r.p.m. Calculate the outer and inner diameters of frictional surface if the coefficient of fricti

What do you mean by issued for review, Q. What do you mean by Issued for Re...

Q. What do you mean by Issued for Review? This drawing issue of P&IDs is a draft and is intended for the Colt-internal review process involving affected disciplines. This draw

Determine the tension and reaction in cable - mechanics, Q:  The12m boom A...

Q:  The12m boom AB weight 1 KN, the distance of center of gravity G is 6 m from point A.  For the position given, determine the tension T in cable and reaction at B.

Laws of solid friction, Laws of solid friction: Sol.: The friction w...

Laws of solid friction: Sol.: The friction which exists between two surfaces that are not lubricated is called as solid friction. The two Surfaces can be at rest or one of t

Explain about surface preparation, Q. Explain about Surface Preparation? ...

Q. Explain about Surface Preparation? All oil, grease, salts, and any other contaminants detrimental to the formation of a good coating bond or coating quality must be removed

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