Deformation (engineering)

In engineering, deformation is the change in size or shape of an object when subjected to force, and may be elastic or plastic depending on whether the deformation is reversible when the actuating force is removed. An object's intrinsic resistance to deformation is known as its stiffness or rigidity. If the deformation is negligible under stress, the object is said to be rigid; conversely, it is said to be flexible or pliable.