A COMPACT, ROBUST AND VERSATILE MOIRE INTERFEROMETER

A moire interferometer was designed and constructed based on a general system design using a reflective crossed-line diffraction grating to produce the four beams of light necessary for moire interferometry. Th e design concept, basic design and tuning procedures are discussed. Th e important features of the interferometer, i.e. compactness, versatil ity, polarization insensitivity, relaxed collimation requirements, low laser power and remote optics, are addressed. Several such interferom eters have been constructed and successfully applied to engineering pr oblems. These include examining the displacement fields surrounding dr illed and preformed holes in composite laminates loaded in tension, an d the evaluation of nonhomogeneous behavior in textile composites.