A fibre optic sensor for ambiguity measurement of apparent strain produced by electrical strain gauge-transient-heating-effect

Strain gauges are useful sensors in many engineering and medical applications. In case of using one gauge for measurement; quarter-bridge configurations, current flowing when power is delivered to the electrical strain gauge causes temperature rise; transient heat effect (THE); and consequently apparent strain appearing as drift of the zero baseline. Fiber optics has been used to measure both temperature and strain or force. The aim of this study is to evaluate temperature rise produced by the electrical strain gauge and in accordance determine the equivalent apparent strain as a step towards using the reading to correct for the error due to the (THE). Results of this study showed that optical fibers sensor is more sensitive compared to the semiconductor sensor which has been used as a reference temperature sensor. Results, also showed the feasibility of determining the equivalent apparent strain values through reverse calculation of number of fringes resulting from the fiber optic sensor due to the temperature change. This was as an initial step to implement those values in the measuring electronic circuitry in order to eliminate the drift in the zero baselines. Uses of such fiber optic sensors are very useful when conducting high precision measurements and in measuring the ambiguity of the electrical gauge sensing system as well as eliminating such ambiguity.