Enhanced Noncontacting Laser Extensometer for Biaxial Strain Measurements

In the proposed program, OPTRA will develop and commercialize a non- contact biaxial extensometer for the material testing market. The optical technology, based on an existing OPTRA single axis product, allows the accurate measurement of surface strains on any test specimen without contact and without material preparation. The non-contact measurement in ideal for high temperature testing, single fiber testing, high humidityliquid immersed testing, high strain elastomer testing and many other applications that are unsuitable for bonded gages. The incorporation of two axes of strain measurement in a single instrument allows users to measure shear strain, Poissons ratio, and other biaxial strain conditions. The ability to reorient the measurement axes relative to the test specimen in real time with small cyclic loading allows the user to rapidly identify the maximum and minimum normal strain axes and thereby fully define an unknown state of plane strain. The product development will be focused on meeting a wide range of material test requirements and on keeping production costs low to insure that a commercially viable product is produced... . Strain measurements, Poissons ratio, Noncontact measurements, Laser extensometer, Mechanical testing, Biaxial strain.