- 2069 Asar · 4 marks
Concept of rigid and deformable bodies
Short answer
A rigid body is an idealization that does not deform; the distance between any two points remains constant, used in statics where transmissibility applies. A deformable body changes shape and size under load, with varying point distances, and is studied in strength of materials for stress and strain analysis.
Write down the concept of rigid bodies and deformable bodies.
Rigid body
A rigid body is an ideal body that does not change its shape or size under any load. The distance between any two of its points stays constant. Statics assumes bodies to be rigid, so the equations of equilibrium can be applied to the original geometry, and the principle of transmissibility holds. A steel beam under a small load is treated as a rigid body when its support reactions are found.
Deformable body
A deformable (real) body changes its shape and size, that is, it stretches, bends or twists, when forces act on it. The deformation depends on the material and on the size of the load. The distance between its points changes. Deformable bodies are studied in strength of materials, where stress, strain and deflection are found. Rubber and a spring are good examples of bodies whose deformation is large.
| Point | Rigid body | Deformable body |
|---|---|---|
| Deformation | None | Present |
| Distance between points | Constant | Changes |
| Used in | Statics, dynamics | Strength of materials |
| Transmissibility | Valid | Not valid |
In practice every body is deformable, but when the deformation is very small it is neglected and the body is treated as rigid.
✓ Answer checked by Claude Opus 5.5 (high effort)
Related questions
- Rigid vs deformable bodies; free body diagram · Applied Mechanics, chapter 2 · asked 2×
- Concept of particle, rigid and deformable body · Applied Mechanics, chapter 1
- Rigid and deformable body; FBD principles · Applied Mechanics, chapter 2