++++ ++++ ++++ ++++ ++++ Concept Question ++++ ++++ ++++ ++++ ++++ Which of the following statements is correct? 1. The PVD only applies to linear elastic materials 2. The PVD applies only to elastic materials, but they can be linear or non-linear 3. The PVD applies regardless of the constitutive behavior of the material 4. The PVD only applies to materials having a well- de?ned strain energy density that depends on the state of strain and not on the strain path or history. 1. ++++ Statements (1) 2. ++++ Statement (2) and (4) 3. ++++ Statement (3) 4. ++++ All of the above statements but state- ment (3) 5. ++++ DKDU The answer to this concept question is: (3) ++++ Statement (3)