Estimation of the deflection field over a ship structure model based on pointwise measurements

This paper presents a methodology that allows using large (in time) but sparse (in space) data from sensors to get a full picture of the dynamic response of a scaled model catamaran structure. Increasing the amount of information relative to the structural behavior is critical for some applications like structural health monitoring and condition-based maintenance. Loads and elastic deflections are estimated by combining the information obtained from the measured structural data with a finite element model of the system given that some statistical properties of the external inputs are preliminary known. Craig-Bampton method is used to achieve a reduced-order model since it is particularly suited to describe the modal response along with the estimation of the concentrated loads. A natural second-order observer is then defined to provide an optimal estimation of forces and elastic deflections along the hull structure. The validation of this technique is pursued by comparing estimated and known values of the response and a sensitivity analysis of the accuracy with respect to some parameters is considered as well.