What is plastic stress?

Plastic stress usually refers to the stress state in the plastic material. In engineering and materials science, stress is a measure of the internal forces in a material, usually per unit area. Stress in plastics can be caused by externally applied forces, temperature changes, humidity changes, etc. Stress on plastic may cause deformation, cracking or other forms of damage. In engineering, understanding and managing stress in plastics is one of the important factors in designing and manufacturing reliable products.