Competency Group: Material Science
Type: Measure Hardware
Description: Harness measurements identify the resistance of a material to deformation, usually measured by indentation. However, the term may also refer to stiffness or temper, or to resistance to scratching, abrasion, or cutting. It is the property of a metal, which gives it the ability to resist being permanently, deformed (bent, broken, or have its shape changed), when a load is applied. The greater the hardness of the metal, the greater resistance it has to deformation. E.g. How resistant is a material to wear — brake disks.
Citation for Description: Center for Advanced Life Cycle Engineering. (2001). Material Hardness. Retreived from http://www.calce.umd.edu/TSFA/Hardness_ad_.htm
Advantages: Offers an idea how much a material is resistant to continual application of abrasive forces. For example if a motor is being applied to a material its longevity can be a function of its hardness.
Limitations: There are a number of different test methods for testing the hardness of a material so they are all relative to each others units.
Regulations: ASTM International. (n.d.) ASTM E140 — 07. Retrieved from http://www.astm.org/Standards/E140.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: NDT (Nondestructive Testing) Resource Center (n.d.). Hardness. Retrieved from http://www.ndt-ed.org/EducationResources/CommunityCollege/Materials/Mechanical/Hardness.htm
Free Resource: Engineers Edge. (2012). Hardness Testing Overview. Retrieved from http://www.engineersedge.com/manufacturing_spec/hardness_testing.htm