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Showing posts from October, 2010

Shear centre

The Shear centre is a point where a shear force can act without producing any twist in the section. At  Shear centre of a section the applied force is balanced by the set of shear forces obtained by summing the shear stresses over the section. Shear centre is also known as the centre of twist. When the load does not act through the shear center, in addition to bending, a twisting moment will develop  in the section.  The location of the shear center is independent of the direction and magnitude of the transverse forces. In unsymmetrical sections and in particular angle and channel sections, the summation of the Shear Stresses in each leg gives a set of Forces which must be in equilibrium with the applied Shearing Force. (a) Consider the angle section which is bending about a principal axis and with a Shearing Force F at right angle to this axis. The sum of the Shear Stresses produces a force in the direction of each leg as shown above. It is clear that their resultant passes through t

Engineering Mechanics -system of Forces

Engineering mechanics or Applied mechanics is  a branch of the physical sciences and the practical application of mechanics.  Much of modern engineering mechanics is based on Isaac Newton's laws of motion while the modern practice of their application can be traced back to Stephen Timoshenko, who is said to be the father of modern engineering mechanics.    Engineering Mechanics is divided into two parts Statics and Dynamics. Statics: It is a branch of mechanics which studies the effects and distribution of forces of rigid bodies which are and remain at rest. In this area of mechanics, the body in which forces are acting is assumed to be rigid .  The deformation of the body is treated in Mechanics in the name of Solid Mechanics or Strength of Materials. Force - It may be defined as any action that tends to change the state of rest of a body to which it is applied.  Newton's laws of motion are three physical laws that form the basis for classical mechanics.  Newton's