Competency Group: Material Science
Type: Measure Hardware
Description: Strain is measured by the forumla Strain = Change in Length/Original Length. E.g. How much can you "stretch" a material before it breaks. For both stress and strain measurement it is important to see how a material behaves when it is subjected to a force where it is compressed or elongated. At some point with most material there will be a point when a sample of the material will break. This gives the upper limits of physical properties of a material.
Citation for Description: Description by authors
Units: Ratio — no units
Advantages: Important to know how pliable and durable a material is. Important to know that the modulus of elasticity of a material can be given as stress/strain.
Limitations: The strain measurement can be a property that is not constant for all shapes and sizes of a material.
Regulations: ASTM International. (n.d.). ASTM D4535 — 08 Standard Test Methods for Measurement of Thermal Expansion of Rock Using Dilatometer. Retrieved from http://www.astm.org/Standards/D4535.htm
Target Audience: Engineering, R&D
Relevant to Universal Design: No
Stages and Steps: 2.2, 4.2, 4.3, 4.12, 7.1, 7.2
Free Resource: Strain gauge. (2012). Retrieved from Wikipedia, http://en.wikipedia.org/wiki/Strain_gauge
Free Resource: Engineers Edge. (2012). Full Bridge Strain Gage Transducer Beam Deflection
Point Loading (Full Bridge) Calculator. Retrieved from http://www.engineersedge.com/strain_gage/full_bridge_straingage.htm"