Optimization of sensor placement to detect damage in flexible plates

Micro electro-mechanical systems (MEMSs) are currently attracting much interest as sensing components for surface-mounted structural health monitoring systems. This contribution provides an approach to the optimal deployment of arrays of MEMS accelerometers over homogeneous thin plates to feel the local change of slope due to the inception or growth of damage, under slowly varying loadings. The optimal sensor placements provided by two physically-based objective functions are investigated, combining results from sensitivity analysis to maximize the capability of detecting, respectively, both the effects of damage and the damage itself. For both objectives the aforementioned sensitivity of the structural response to damage, possibly located anywhere in the plate mid-surface, is computed all over the domain through an ad hoc finite element analysis based on first-order shear deformation theory. Details of the formulation are discussed, showing how concepts belonging to topology optimization may be straightforwardly extended to the optimal deployment of sensor arrays.