nondeformable

Nondeformable describes a material or body that does not undergo any deformation when subjected to external forces. In science and engineering, the term is often used interchangeably with rigid or undeformable to denote an idealized solid that resists bending, stretching, and compression.

It is used as an idealization in mechanics to simplify analysis. In a nondeformable (rigid) body, the distances between all material points remain constant during motion, so the body's movement consists of a rotation and translation. This leads to the concept of rigid-body dynamics, where equations of motion track the position and orientation of the body rather than internal strains.

Applications include the study of linkages, gears, and robot joints, as well as simplifications in contact problems and structural analysis where deformations are negligible compared to overall motions. In numerical methods such as finite element analysis, certain components may be modeled as nondeformable to reduce computational complexity.

Limitations: no real material is perfectly nondeformable; all materials experience some strain under load, and factors like load magnitude, rate, temperature, and time can cause elastic or plastic deformation. The nondeformable assumption is valid only within specific regimes where strains are vanishingly small.

Related topics include rigid body dynamics, elasticity, and deformation.