**Shear centre of a section can be defined as a point about which the applied force is balanced by the set of shear forces obtained by summing the shear stresses over the section.**

**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 principle 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 the corner of the angle and unless F is applied through this point there will be a twisting of the angle as well as Bending. This point is known as**

**The Shear Centre or Centre of Twist**

**(b) For a channel section with loading parallel to the Web, the total Shearing Force carried by the web must equal F and that in the flanges produces two equal and opposite horizontal forces. It can be seen that for equilibrium the applied load causing F must lie in a plane outside the channel as indicated.**

**Note:**

**1. In case of a beam having two axes of symmetry, the shear centre coincides with the centroid.**

**2. In case of sections having one axis of symmetry, the shear centre does not coinside with the centroid but lies on the axis of symmetry.**

**3. When the load passes through the shear centre then there will be only bending in the cross section and no twisting.**

**Problem : 1**

**A shear center of an H-section with unequal flanges is located nearer to the bigger flange. If the smaller flange is 16mm x 100mm the larger flange is 16mm by 200mm, and the web is 9mm by 284mm. the distance of the shear center from the center of the bigger flange is:**H-SECTION |

**Solution:**

thank u sir....I got the concept...

ReplyDeletecan this concept used for unsymmetrical lipped c section ?

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