Identification of the Tensile Force in a Cable with Insulators Using a Bayesian Approach

Abstract

Guyed towers are common structural types of extended use in the communication industry. In some cases, due to technical requirements, insulators are necessary. One of the techniques to estimate the pretension force in a cable is through the measurement of its natural frequencies and the related code standards include specific formulae. However, the presence of the insulators leads to a different situation which is not considered in the codes. In this paper, a Bayesian approach is applied to the identification of the tensile force in a prestressed cable with insulators. Firstly, a physical model of the cable is constructed in the laboratory. A high speed camera is used to register the displacements of the structure undergoing free vibrations. The videos are analysed using a specific software and the time series response is obtained. With this information, the natural frequencies of the cable with insulators are evaluated. Additionally, a Finite Element model of the cable is built. Then, the Bayes rule is implemented through Markov-Chain Monte-Carlo (MCMC) simulations and, as a result, the probability distribution of the cable tension is obtained. The estimates are compared with the true value of the tensile force acting on the physical configuration of the cable. Finally, the uncertainties in the inferred values are propagated through the computational model and the frequency response is evaluated.