Stress

Stress is the loading applied   on the material while strain is the deformation that results due to application of load or stress. By this definition, it is obvious that stress and strain are related and that relationship can best be explained by considering a stress-strain curve (Figure 1). Building materials have their own corresponding stress-strain curve which can be obtained by recording the amount of deformation (strain) upon application of tensile or compressive loading. Curve results reveal the behavior or properties of materials when load (weight) is applied.

Figure1. Stress-Strain curveConsider the Stress-Strain curve of building materials in Figure 1. For concrete materials, its curve is almost a straight line and ends rather abruptly. This means that concretes easily fractures or fails (brittle material). Likewise, the resulting curve for cast iron is straight indicating that it too is brittle. However, as the graph indicates it can withstand higher stress before failure than concretes do. Nevertheless, both of these materials will fail or fracture with little warning once their limits (maximum loading) are exceeded.

Mild steel on the other hand, has a gentle curving at the top. This means that mild steel has different properties than cast iron or concrete. The gentle curving signifies that after certain point mild steel will continue to strain (in the case of tension, to stretch) as the stress (the loading) remains more or less constant. This indicates a high ductility. However, at certain point, or maximum bearable loading, the material will not continue to stretch but will ultimately fail.

Get quality help now

KarrieWrites

Verified

Proficient in: Chemistry

5 (339)

“ KarrieWrites did such a phenomenal job on this assignment! He completed it prior to its deadline and was thorough and informative. ”

+84 relevant experts are online

Hire writer

Stress can be applied to building materials in two ways: by compression or stretching (tensile).    Compressive strength is the maximum stress that a material will bear when it is subjected to a load that pushes it together. Tensile strength is the maximum stress a material will bear when it is subjected to a stretching load(Luebkeman 1997). ReferenceLuebkeman, Chris H. and Donald Peting. (1997). Stress-Strain Curves. Retrieved 12 October 2007 from http://darkwing.uoregon.edu/~struct/courseware/461/461_lectures/ /461_lecture24/461_lecture24.html