ABSTRACT
A l l materials change shape when subject to load. At microscopic level, the stresses acting on an incremental element wi l l cause changes in the dimensions of the element. These changes called 'strains' cause the structure to deflect. Most structures obey Hooke's Law, which states that stress is proportional to strain, over a significant part of their loading range. For loading within this range, the material is said to be linear elastic. The term 'elastic' implies that there is no loss of energy and so the material wi l l revert to its original state when unloaded.
