<title>Finite element modeling and simulation of fiber optical based load cell (FOLC) sensor</title>

Abstract

Optical techniques have played an important role in telecommunication, industrial instrumentation and the sensors fields. In telecommunication field, the fiber optic technology is now firmly established for voice and data transfer. Wider bandwidth, low attenuation and mechanical properties of the fiber, are among the major advantages of optical fiber systems, even in the presence of various extreme and hazardous environmental conditions. The applications of optical fibers in the field of sensors are well established. This paper reports on development, modeling and simulation of fiber optic load cell (FOLC) sensor. The sensor basically consists of a fiber optic micro-displacement sensor probe and a load sensing diaphragm which also acts as a reflector. A pan is used for keeping the weights, the load of which is transferred to the diaphragm by a pin. The geometrical information of developed sensor is translated into a 3-D model. The stresses and deformations generated in the diaphragm are calculated using finite element method. Results for loading conditions ranging from low (mg) to high (100s of kg) levels and diaphragm parameters like thickness, diameter, Young's modulus and tensile strength are obtained. The fiber optic micro displacement sensor then senses the resulting deformations. A Ray Tracing module is used to study the relation between received intensity and position of fiber probe. The simulation results match well with the experimental results. The sensor dimensional parameters, geometry and material parameters of the diaphragm are optimized and are reported in the paper. It is hoped that this non-contact Load Cell sensor will offer several benefits over the conventional strain gauge based load cells.