Measurement of thermal expansion coefficients with holographic technique

Abstract

A simplified mathematical model was created for measurement of thermal expansion coefficients of thin sheet materials with holographic technique. Experimental set-ups corresponding to the mathematical model were designed and built for both tests above room temperature and at low temperatures. A fringe control technique was introduced for low temperature measurements to compensate rigid body movement. Thin sheet specimens of silicon and aluminum alloy (7075) were tested with the developed technique. The tested results are in good agreement with reported data and thus verify the validity of the developed technique. The thermal expansion coefficients of the tested materials ranged from 2.5 × 10−6°C−1 to 23.6 × 10−6°C−1.