Lecture Notes of Couples

University of Babylon
College of Engineering
Department of Environmental Engineering
Engineering Analysis I (ENAN 103)







Couples

Undergraduate Level, 1st Stage



Mr. Waleed Ali Tameemi
College of Engineering/ Babylon University
M.Sc. Civil Engineering/ the University of Kansas/ USA



2016-2017

Course Outline
Introduction
Parallelogram Law
Forces Resolution
Resultant of a Cunccurent, Coplanar Force System
Moment
Couples
Resultant of a Non-concurrent, Coplanar Force System
Resultant of a Concurrent Non-coplanar Force System
Equilibrium
Fraction
Truss
Method of Joints
Method of Sections







Couples
A couple is produced by two forces that are equal in magnitude, parallel, and opposite in the direction. Couples are only tending to rotate subjects around known axis.
The magnitude of the couple can be calculated as the algebraic summation of the moments of its forces around any axes perpendicular to the plane of the couple






M_couple=F×d/2+F×d/2=F×d








Moments and Couples Sign Convention
Positive sign (+ve), if the couple is rotating counter clockwise.






Negative sign (-ve), if the couple is rotating clockwise.