Basic Concepts:

Rigid and Deformable Solids

The subject matter of Strength of Materials is also understood under the title Applied Mechanics, and Mechanics of Solids. Applied Mechanics is the common title in that Fluid Mechanics and Solid Mechanics are branches. What we study in Strength of Materials is the effect of forces acting on solids of various geometrical and elastic properties, and thus more people now choose to call it Solid Mechanics.

Let us now learn two terms used to elaborates two categories of solids. A rigid solid is one that does not undergo any change in its geometry, size or shape. Instead, a deformable solid is one in that change in shape, size or both will occur while it is subjected to a force. The geometrical changes generates are known as deformations and therefore the name deformable solid. Several of the common solid articles we handle in our day-to-day life exhibit perceptible deformations while subjected to loads. In many other solids, though we might not perceive any deformations along with our naked eye, along with measuring instruments of sufficient precision we could see in which they also get deformed under applied forces. A more careful scrutiny will reveal in which all solids are deformable and the idea of rigid solids is just a conceptual idealisation.