Structural Materials

Structural materials are used in their elastic range, although their formation into a usable shape normally requires taking them into their plastic deformation range. The elastic and plastic properties of materials must therefore be understood before a selection can be made.

The basic information about these properties is summarized in a stress-strain curve, where stress is related to the applied load and the sample area and the strain quantifies the change in the sample dimension under load with respect to its initial dimension. For the sample shown in the diagram, the nominal stress, s = F/A₀ , and the nominal strain, e = DL / L₀ , where A₀ and L₀ are the initial area and length of the sample. In the elastic response range, Stress and Strain are connected by Hooke's Law through an elastic constant such that: Stress = E (Strain) , where E is known as Young's modulus.

From: Callister, "Materials Science and Engineering," Wiley (1997)