Optimal sensor placement of triaxial accelerometers for modal expansion

Sensor placement is a vital factor affecting the quality and accuracy of virtual sensing. Modal expansion techniques are well-known methods to expand the measured displacements or accelerations to all unmeasured degrees of freedom. For this purpose, a two-phase sensor placement optimisation method is proposed for commonly used triaxial accelerometers. The method uses minimum variance criterion of an estimation error of structural responses. A measure of redundancy of information is introduced as an additional criterion for the placement of the triaxial sensors to minimise the redundancy between the sensors. This was addressed to avoid spatial correlation and clustering of the sensor locations. In addition, a proposal for modal displacementbased weighting is introduced to avoid potential selection of sensor locations with low vibration energy, which can be critical in noisy environments. The efficiency of the proposed method is verified with numerical models of different types of structures and finally with the laboratory scale experiments. The mean error of the reconstructed response in this particular experimental case study was 1.4% of the maximum measured response amplitude. This method is especially applicable to large finite element models of industrial-scale structures with fine meshes.

Automated summary

Sensor placement is a crucial factor in determining the quality and accuracy of virtual sensing. This study proposes a two-phase optimization method for triaxial accelerometers, using minimum variance criterion and a measure of redundancy of information. The method successfully avoids spatial correlation and clustering of sensor locations and introduces a weighting proposal based on modal displacement to enhance selection of sensor positions in noisy environments. The effectiveness of the method is demonstrated through numerical models and laboratory experiments. The average error in response reconstruction was found to be 1.4% of the maximum measured response amplitude. This method is particularly suitable for large finite element models of industrial-scale structures with fine meshes.