Why is any metallic part of a machinery never subjected to a stress beyond the elastic limit ?

TRUE/FALSE TYPE QUESTIONS Any metallic part of a machinery is never subjected to a stress beyond the elastic limit of the material.

On applying external force beyond the elastic limit,

The metal which do not break beyond elastic limit is

The property of metals where by they could be drawn into thin wires beyond their elastic limit without breaking is

Materials get deformed when force is applied. Some of them regain their status when the applied force is removed. They are termed as elastic. Those of which not regaining are called plastic. There may be delay in the regaining in some materials. They are said to have got elastic aftereffect, since they have gone beyond the elastic limit. Repeated application and removal of force leads to fatigueness in the material. Fatigued materials may break at any point time and so are avoided. The stress strain graph for two materials A and B is shown in the following figure: The time in which the two materials regain their original status is t_(A) and t_(B) related as t_(B)=2t_(B) . Then the material under elastic aftereffect (relatively) is

Materials get deformed when force is applied. Some of them regain their status when the applied force is removed. They are termed as elastic. Those of which not regaining are called plastic. There may be delay in the regaining in some materials. They are said to have got elastic aftereffect, since they have gone beyond the elastic limit. Repeated application and removal of force leads to fatigueness in the material. Fatigued materials may break at any point time and so are avoided. The stress strain graph for two materials A and B is shown in the following figure: If the intensity of A and B is E_(A) and E_(B) , respectively

Materials get deformed when force is applied. Some of them regain their status when the applied force is removed. They are termed as elastic. Those of which not regaining are called plastic. There may be delay in the regaining in some materials. They are said to have got elastic aftereffect, since they have gone beyond the elastic limit. Repeated application and removal of force leads to fatigueness in the material. Fatigued materials may break at any point time and so are avoided. The stress strain graph for two materials A and B is shown in the following figure: The strength of the material A and B is S_(A) and S_(B) , respectively, while the longevity of plastic behaviour is L_(A) and L_(B) . Then

The shape of stress vs strain graph within elastic limit is :