In
materials science,
deformation refers to any changes in the shape or size of an object due to-
- an applied force (the deformation energy in this case is transferred through work) or
- a change in temperature (the deformation energy in this case is transferred through heat).
The first case can be a result of
tensile (pulling) forces,
compressive (pushing) forces,
shear,
bending or
torsion (twisting).