ABSTRACT
You will be familiar with simple stress and strain relationships from your previous study and from the material presented in section 1.5 of Chapter 1, where only stresses and strains in one dimension were considered and the stresses resulting from the loads were considered to be uniform across the whole cross-section of the material. Engineering materials and structures are generally subject to a combination of loading situations that set up a complex network of stresses and strains within the material. For example, a structure such as a roof truss for a building may be subject to a combination of tensile, compressive and torsional loads, resulting in a complex set of two-or three-dimensional stresses and resultant strains that may act in different directions on any particular element of the material within the truss.
