Strain

This chapter begins with the definition of strain from the continuum mechanics point of view, the description of the strain tensor and the strain transformation concept; then, the elastic stress strain relations, namely the constitutive equations, are described for both isotropic and anisotropic behavior. Next is the description of plasticity and plastic behavior of metallic materials, including tables of typical mechanical properties of engineering materials, the following topics are the Baushingher effect, the concepts of real stress and real strain, and the plastic stress-strain equations. A brief introduction of the numeric analysis of stress and strain is presented, along with a description of the procedure to perform an analysis of mechanical behavior by the Finite Element Method and a brief description of the experimental methods of electric resistance extensometry and polaroscopy to measure stress and strain. At the end of this chapter an introduction to the hardness concept and the standard methods to measure it is presented.