Any spring material has physical properties, which means that as the force gradually increases from zero, it begins to deform for a period of time proportional to the magnitude of the force. At this point, gradually reducing the force to zero will restore the shape of the object. But when the force reaches a certain magnitude, plastic deformation will occur, and the shape of the object will change permanently, and at this time, the relationship between force and deformation is no longer proportional.

In our daily lives, items such as springs utilize the proportional aspect of the object and do not want to undergo long-term deformation, hence the term ‘deformation range’. The deformation range is related to the material, geometric shape, temperature, and other factors of the object.