MEASUREMENT OF BIAXIAL DISPLACEMENT BY A SPECKLE CORRELATION METHOD AT HIGH-TEMPERATURE

Biaxial displacement of a buttonhead tensile-torsional specimen surfac e mas measured by a speckle correlation method at 800 degrees C. A hig h-power argon gas laser of 488 nm wavelength and band-pass filters mer e used to improve the signal/noise ratio at high temperature. In the c ase of displacement parallel to a specimen axis, calculated values by the speckle correlation agreed with the displacement measured with a d ial gauge. For the perpendicular direction, agreement was also obtaine d, taking into account an additional correction. These biaxial displac ements mere measured in real time.