Shear center

The shear center, also called shear center or drill resting point, is the point of a profile cross-section through which the resultant of the lateral forces have to go to reach to avoid twisting force, or to exert no twist on the cross section.

In this case, all the forces are regarded as transverse forces acting on the profile in a sideways direction. The simplest example is the load that acts on a U- jacked up carrier. Contrary to the lateral force is the longitudinal force, which acts in parallel to the profile area in the longitudinal axis of the profile strip or.

The shear center falls at full profiles together with the center of gravity. Thin-walled cross-sections, however, the influence of the edge zones is large, so that the shear stresses follow the profile history, since only tangential stresses occur at a free surface. The shear stresses, which are to some extent guided by the profile curve, can produce a moment on the priority depending on the profile. The shear center is the point at which the torque disappears as a result of the shear stresses. For double- symmetrical profiles (eg I-sections ) of the shear center is identical with the center of gravity. For profiles with only one symmetry axis, it is on this, but does not coincide with the center of gravity. In U- profiles, for example, it is opposite the center of gravity outside the profile cross section.

The formula for calculating the shear center of thin single balanced cross-sections:

Where:

For thin-walled, star-shaped profiles of the shear center lies at the intersection.

Information concerning the shear center of the profile cross -sections which are not national or doubly symmetrical, often applicable only under the assumption of a thin profile. Information for thick-walled profiles require complicated calculation procedures.

• Engineering Mechanics