Transversal load measurement based on twisted optical fibers

Abstract

An evaluation of two optical fiber sensing heads for measuring transversal load is presented. Their construction introduces power loss without the need of a pair of deformer plates and is based on crossing two fibers in braid-type (braid twisted), and of an optical fiber stretched out which is wrapped up by another one in spiral form (spiral twisted), respectively. For a higher sensitivity, the braid twisted configuration is preferable. Nevertheless, in both sensing heads, the sensitivity can be enhanced by decreasing the enrollment period and/or by choosing the appropriate encapsulation of the sensing head. Relative to resolution and hysteresis, the spiral twisted sensing head presented the best result. However, further work on the plasticity of the coatings is needed to decrease hysteresis. These configurations can be embedded in composite materials and used in many applications. © 2005 American Institute of Physics.