Fuzzy modeling of refractory cement viscosity to improve thermocouples manufacturing process

Abstract

Refractory cement is one of the elementary materials for the thermocouples manufacture. It is important pointing out that viscosity greatly affects its quality and functionality. In this sense, there is a viscosity range in which refractory cement must be applied; this range is known as “pot life.” For this reason, the cement setting process (viscosity behavior) should be modeled in order to predict its life (useful time). Like this, some operational factors must be considered, among them: temperature and humidity as well as the fact that pot life behavior is nonlinear and must be performed by a growth model. At the modeling process, it is necessary considering the uncertainty which is not considered in the properties of the bodies studied in the rheological models for real materials. This work proposes an inverse prediction method for measuring the prediction error time. Furthermore, it is suggested performing the estimated times by a triangular fuzzy number with the purpose of considering all uncertainty information and providing a reliable prediction. Therefore, the fuzzy theory to the Weibull analysis was adapted in order to estimate some faculties: the fuzzy reliability, the fuzzy useful time with a desired reliability and the fuzzy mean pot life. Results show accuracy and useful pot life predictions.