Remote optical measurement of thermal and mechanical properties of engineering structures

摘要

Performance of an optoelectronic setup allowing heating of a remote engineering structure and subsequent analysis of the resulting deformation is described. The structure is heated by a CO_2 laser beam. This gives rise to a thermal stress in the heated region and to a global deformation of the structure. The latter cited is also illuminated by a HeNe laser beam. The light intensity distribution in the backscattered HeNe light wave is digitally recorded and processed by convenient software, which yields the structure deformation and allows the remote observer to get information about its thermal and mechanical properties. A typical application of the setup, consisting in remote damping of free vibrations of a cantilever bar, is presented.