Strain is defined as the gradual, continuing irreversible deformation due to constant stress below yield stress.

Strain is defined as the gradual, continuing irreversible deformation due to constant stress below yield stress.

• A. True
• B. It is only elastic
• C. False
• D. Irreversible only at yield

Answer: (C)

Strain is a measure of how much a material deforms in response to an applied load, and it can be either elastic (reversible) or plastic (permanent). The statement describes irreversible deformation under a constant load that is below the yield stress. That would imply creep, a time-dependent and often temperature-sensitive phenomenon, not the general, blanket definition of strain. In most structural metals at room temperature, staying below the yield stress produces primarily elastic, reversible deformation when the load is removed. Irreversible deformation under sustained load below yield is not the normal, universal behavior described by strain. So the statement is not a correct general definition of strain.

Strain is a measure of how much a material deforms in response to an applied load, and it can be either elastic (reversible) or plastic (permanent). The statement describes irreversible deformation under a constant load that is below the yield stress. That would imply creep, a time-dependent and often temperature-sensitive phenomenon, not the general, blanket definition of strain. In most structural metals at room temperature, staying below the yield stress produces primarily elastic, reversible deformation when the load is removed. Irreversible deformation under sustained load below yield is not the normal, universal behavior described by strain. So the statement is not a correct general definition of strain.