Engineering Commons^™

Straining Definitions, William Pollalis, Santiago Pujol

The Summer Undergraduate Research Fellowship (SURF) Symposium

The concept of strain is ubiquitous in engineering textbooks. It is defined early in engineering education as change in length divided by initial length, and is used to quantify deformations due to things like stresses and temperature changes. The concept itself is quite straightforward and represents homogenous materials well, but homogenous materials are rarely present in engineering design. Composite materials such reinforced concrete cannot be simply defined, as their properties are heavily influenced by their non-uniformity. For example, there are large deformations around tensile cracks in reinforced concrete, where the reinforcement withstands all the tensile stress, and little deformation in …