Optimal sensor placement of triaxial accelerometers for modal expansion

• Published in: Mechanical systems and signal processing 2023-02, Vol.184, p.109581, Article 109581
• Main Authors: Nieminen, Vesa, Sopanen, Jussi
• Format: Article
• Language: English
• Subjects: Information redundancy; Optimal sensor placement; Structural health monitoring
• ISSN: 0888-3270; 1096-1216
• DOI: 10.1016/j.ymssp.2022.109581

•Optimal sensor placement for triaxial sensors for modal expansion is proposed.•The method is based on minimum variance criterion of an estimation error.•Redundancy information is applied as a constraint in the sensor placement.•A proposal to avoid selection of sensor locations with low energy.•Method is validated by laboratory scale experiments. 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 displacement-based 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.