Layout optimization of wireless sensor networks for structuralhealth monitoring

Node layout optimization of structural wirelesssystems is investigated as a means to prolong the network lifetime without, if possible, compromising information quality of the measurement data. The trade-off between these antagonisticobjectivesis studied within a multi-objective layout optimization framework.A Genetic Algorithm is adopted to obtain a set of Pareto-optimal solutions from which the end user can select the final layout. The information quality of the measurement data collected from aheterogeneous WSNis quantified fromthe placement qualityindicators of strain and acceleration sensors. The network lifetime or equivalently the network energy consumption is estimated throughWSNsimulation that provides realistic results bycapturing the dynamics of thwireless communication protocols. A layout optimization study of a monitoring system on the Great Belt Bridge is conducted to evaluate the proposed approach.The placement quality of strain gauges and accelerometersis obtainedas a ratio of the Modal Clarity Index and Mode Shape Expansion values that are computed from a Finite Element model of the monitored bridge. To estimate the energy consumption of the WSN platform in a realistic scenario, we use adiscrete-event simulator with stochastic communication models. Finally, we compare the optimizationresults with those obtained in a previous work where the network energy consumption is obtained viadeterministic communication models.