Effect of specimen length on accuracy of thermal-expansion measurement.

The coefficient of linear thermal expansion is a basic physical quantity of interest in many industrial applications. In particular, in order to properly use data in the design phase of a product, accurate thermal expansion of a material should be obtained in a certain temperature range. Correction of the measuring equipment is required to obtain a high accuracy; reference specimens are used for the correction. The reference specimen should have the same properties and length as the test specimen. However, reference materials with a similar structure and length identical to the test specimen are not easily available. Therefore, the effect of the specimen length on the thermal expansion is investigated in this study. Measurement results show that the length of the reference specimen has a different effect on the measured value depending on the specimen type. [ABSTRACT FROM AUTHOR]