Strength of Material (General Engineering) (SSC JE)

The value of Poisson's ratio depends upon type of material.
Poisson's ratio–For homogeneous and isotropic material, elongation contraction produced by any axial force in the direction of force is accompanied by contraction in all direction.

For a rectangular beam subjected to external loading, the shear stress will be maximum at the neutral axis of the beam.

Note–Shear stress in a beam is not uniformly distributed over the cross section but varies from zero at outer fiber to a maximum at the neutral axis.

(1) Cantilever beam–A cantilever beam is a rigid structural element supported at one end and free at other end.

Given that,
radius (r) = 220 mm
We know that distance between the reference point O and center of gravity of the lamina.

Determinate structures–These are analysed just by the use of basic equilibrium equations.
• By this analysis, the unknown reactions are found for the further determination of stresses. Example–SSB, cantilever beam, single and double overhanging beams, three hinged arch.
• Indeterminate structure–These are not capable of being analysed by use of basic equilibrium equations. Example–Fixed beam, continuous beam, fixed arch, two hinged arches, portals, multistoried frames.

Hooke's law states that the strain of the material is proportional to the applied stress with in the elastic limit of that matter.