[SOM] Basics of Strength Of Material [Part-3]

Basics of Strength Of Material continued...Part-3

Pure Axial Loading

A member is said to be under pure axial loading when it is subjected to two equal and opposite axial loads in such a way that the magnitude of axial load remains constant throughout the length of the member (ie Axial load =constant, shear force=BM=TM=0).

Pure Bending

A member is said to be under Pure Bending when it is subjected to two equal and opposite couples in a plane along the longitudinal axis of the member (ie Bending couples) in such a way that the magnitude of B.M remains constant throughout the length of the member (ie BM=constant, Axial Load=Shear Force=Twisting Moment=Zero).

Bending Moment

BM at any given cross-section is defined as the algebraic sum of moments either of the LHS of the cross-section or RHS of the cross-section.

Sign Convention For Bending Moment:

Bending Moment at any Cross section is said to be positive: when it is acting in the clockwise direction on the LHS of cross-section or when it is acting in the anticlockwise direction on the RHS of cross-section and vice-versa.

Shear Force

SF at any given cross-section is defined as the algebraic sum of vertical forces either on the LHS of the cross-section or on the RHS of the cross-section.

Sign Convention For Shear Force

SF at a given cross-section is said to be positive: when it is acting in upward direction on LHS of cross-section. Or when it is acting in downward direction on RHS of the cross-section and Vice-versa.

Equivalent Load under Eccentric Axial Load:

Equivalent Load under Transverse Shear Load:

Pure Torsion:

A member is said to be under pure torsion when it is subjected to two equal and opposite couples in a plane perpendicular to the longitudinal axis of the member (ie twisting couple) in a such a way that magnitude of twisting moment remains constant throughout the length of the member (ie TM=Constant, Axial Load=Shear Force= Bending Moment=Zero).

Eccentric Transverse Shear Load

Summary Table of Equivalent Load and their Resultant Effect:

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