MAURBHANJ SCHOOL OF � ENGINEERING�

PRESENTED BY.

: BARENDRA NATH MOHANTA

CHAPTER 4: SHEAR FORCE AND BENDING MOMENT

WHY STUDY STRESSES IN BEAMS

WHAT ARE BEAMS

• A structural member which is long when compared with its lateral dimensions, subjected to transverse forces so applied as to induce bending of the member in an axial plane, is called a beam.

OBJECTIVE

• When a beam is loaded by forces or couples stresses and strains are created throughout the interior of the beam.
• To determine these stresses and strains, the internal forces and internal couples that act on the cross sections of the beam must be found

BEAM TYPES

• Types of beams – depending on how they are supported.

LOAD TYPES ON BEAMS

Types of loads on beam

• Concentrated or point load

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• Uniformly distributed load

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• Uniformly varying load

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SIGN CONVENTION FOR FORCES AND MOMENTS

• Positive directions are denoted by an internal shear force that causes clockwise rotation of the member on which it acts, and an internal moment that causes compression, or pushing on the upper arm of the member.
• Loads that are opposite to these are considered negative.

SHEAR FORCE AND BENDING MOMENT

• SHEAR FORCE : is the algebraic sum of the vertical forces acting to the left or right of the cut section.

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• BENDING MOMENT : is the algebraic sum of the moment of the forces to the left or to the right of the section taken about the section.

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SHEAR FORCES AND BENDING MOMENTS

• The resultant of the stresses must be such as to maintain the equilibrium of the free body.
• The resultant of the stresses acting on the cross section can be reduced to a shear force and a bending moment.
• The stress resultants in statically determinate beams can be calculated from equations of equilibrium.

SHEAR FORCE AND BENDING MOMENT DIAGRAM

SHEAR FORCE AND BENDING MOMENT DIAGRAM

THANK YOU