Patent ID: 8649638

Claim:
A method for measuring the deformation of a specimen comprising the steps of: a) attaching a fiber-optic extensometer to a specimen of interest, wherein the fiber-optic extensometer comprises i) a loop of a single-mode optical fiber; ii) a light source attached to a first end of the loop for transmitting light having an optical power through the loop; and iii) a photodetector attached to a second end of the loop for detecting the light transmitted through the loop, b) transmitting the light supplied by the light source through the loop; c) deforming the specimen while the light is being transmitted through the loop, wherein deformation of the loop changes the optical power of the light being transmitted through the loop; d) using the photodetector to detect any change in optical power of the light passing through the loop; and e) coupling the photodetector to a computer having a database of the calibration curves relating the change in the optical power to the deformation of the loop, wherein the change in the optical power of the light being transmitted through the loop is related to the deformation of the loop using calibration curves.