Optimization of modular wiring harnesses by means of regression models for temperature prediction of wire bundles

Automotive wiring harnesses have become heavier and more complex due to their increasing number of electrical components. It is now desired to reduce their mass of copper. For this purpose, experimentation can be partially replaced by simulation, but it is still impossible to exhaustively simulate all of the combinations of modular wiring harness. This proposed approach consists of carrying out simulations using the FEM method and using their results to create regression models. Polynomial formulae can give the same information as simulations within a clearly reduced time and satisfying accuracy. An optimization algorithm introduced in this study will use them to assign new cable cross-sections of harnesses considering their currents and the ambient temperature.Postprint (author's final draft

Custom integer optimization method for wire bundle dimensioning

Automotive wiring harnesses have gained weight and complexity through the last decades due to the increasing number of electrical components, which has raised the interest on its weight optimization. For this purpose, it is essential to know at least the maximum amount of steady current that either single wires or bundles can carry. However, the large amount of combinations of the customer-speci¿c wire harnesses makes it impossible to exhaustively simulate all of the combinations that would allow for a reliable analysis and optimization of the network. The proposed approach consists of achieving accurate predictions of the wire thermal behaviour using fast on-line polynomial functions, which have been created as regression models using data from off-line worst-case ¿nite element sim- ulations. These regression models provide good accuracy for the critical dimensions of wire bundles in a much shorter time than simulations, so that they can be used on-line in optimiza- tion algorithms. Two different approaches of optimization are presented here in order to assign discrete values of available wire cross-section to the wire bundles: The ¿rst one uses integer linear programming, and the second one consists of a recently created custom algorithm whose objective is to reduce the computation time of the integer linear programming approach. This latter objective is satisfactorily accomplished. Results of both optimization approaches are validated by means of ¿nal ¿nite element simulations, and they promisingly ful¿ll the objectives of this study.Peer ReviewedPostprint (author's final draft

Application of distributed optical fiber sensors for the health monitoring of two real structures in Barcelona

This is an Accepted Manuscript of an article published by Taylor & Francis Group in Structure and Infrastructure Engineering on 2018, available online at: http://www.tandfonline.com/10.1080/15732479.2018.1438479The versatility and ease of installation of Distributed Optical Fibre Sensors (DOFS) compared with traditional monitoring systems are important characteristics to consider when facing the Structural Health Monitoring (SHM) of real world structures. The DOFS used in this study provide continuous (in space) strain data along the optical fibre with high spatial resolution. The main issues and results of two different existing structures monitored with DOFS, are described in this paper. The main SHM results of the rehabilitation of an historical building used as hospital and the enlargement of a pre-stressed concrete bridge are presented. The results are obtained using a novel DOFS based on an Optical Backscattered Reflectometry (OBR) technique. The application of the optical fibre monitoring system to two different materials (masonry and concrete) provides also important insights on the great possibilities of this technique when monitoring existing structures. In fact, the influence of strain transfer between the DOFS and the bonding surface is one of the principal effects that should be considered in the application of the OBR technique to real structures. Moreover, and because structural surfaces generally present considerable roughness, the procedure to attach the optical fibre to the two monitored structures is described.Peer ReviewedPostprint (author's final draft

Fatigue performance of distributed optical fiber sensors in reinforced concrete elements

In this paper, the authors present the results of a laboratory test where two reinforced concrete beams were instrumented with Distributed Optical Fiber Sensors (DOFS) to allow the monitoring g of strain in four different longitudinal segments bonded to their bottom surface. The test objective was to confirm the ability and good performance of the DOFS to monitor bridge structures in a long-term basis. To this end, the two specimens were submitted to a fatigue test up to 2 million load cycles. The amplitude of the stress range applied during the fatigue test was representative of what is expected on a standard highway bridge under vehicular traffic. Additionally, each of the four DOFS segments was bonded using a different adhesive to also investigate on the fatigue performance of the adhesive agents normally used. Finally, the collected data is checked against the data recorded with strain gauges also deployed on the beam specimens.Peer ReviewedPostprint (author's final draft