Final answer:
The maximum stress a material can withstand without permanent deformation is called the elastic limit. Beyond this limit, materials undergo plastic deformation and eventually reach their breaking point or tensile strength, where they permanently fracture.
Step-by-step explanation:
The maximum stress that a structure or material can withstand without being permanently deformed is known as the elastic limit. This is the point on a stress-strain curve that marks the end of elastic behavior and the beginning of plastic deformation. When materials are subjected to stresses beyond the elastic limit, they do not return to their original shape and size once the load is removed and thus become permanently deformed. Beyond the elastic limit, if the stress continues to be increased, the materials will undergo plastic deformation until they reach the breaking point, where they will fracture or break apart. Tensile strength, on the other hand, refers to the breaking stress that will cause permanent deformation or fracture of a material.