Patent ID: 6776520
Filing Date: 2004-08-17
Classification: G01N

Abstract:
A method for determining a coefficient of thermal expansion for a material, comprising:equilibrating the material at a first temperature; imparting a first stress on the material by applying tension to the material; changing the first temperature to a second temperature; equilibrating the material at the second temperature; imparting a second stress on the material by increasing the tension on the material to a second level; determining a stress change of the material; and using the stress change to calculate the coefficient of thermal expansion of the material by graphically determining Young's Modulus using the stress change and a tangential ratio of a stress-strain curve and determining the coefficient of thermal expansion, &agr;, using the equation: Î±=-Î”&it;â€ƒ&it;ÏƒE&it;â€ƒ&it;Î”&it;â€ƒ&it;Twhen Young's Modulus and the coefficient of thermal expansion remain substantially constant and where &Dgr;&sgr; is the stress change, E is Young's Modulus, and &Dgr;T is a temperature difference between temperatures T1 and T2.