Materials and Processes
In the course of your work you will meet and use many different kinds of materials. They will have been chosen for a particular job because their characteristics make them the most suitable material for that purpose. If you are to use and choose materials wisely, you will need
to be familiar with their characteristics, their advantages and their limitations. One of the main properties of a material is its strength. That is, its
ability to withstand force or resist stress. Figure 12.1 illustrates the ways in which stress may be applied to
materials. These stresses are:
(a) tensile or stretching (b) compressive, or squeezing or crushing (c) bending, which is both (a) and (b) on either side of a neutral
axis (d) shear or cutting (e) torsion or twisting.