Theoretical and experimental correlation between finite element models and modal tests in the context of large flexible space structures

Although the field of finite element analysis of structural dynamic has witnessed tremendous progress in the last two decades, more confidence is still placed in experimental data. Therefore, the finite element model of a given structure is often updated to reflect the results of a particular experiment.; Updating methods must account for the complexity of modal testing methods and system identification techniques while still generating physically acceptable adjusted models. A Sensitivity-Based Element-By-Element (SB-EBE) method for improving finite element models using test modal data has been developed. The SB-EBE method searches for both the location and potential sources of the detected errors, and does not interfere with the theory behind the finite element model while correcting these errors. An updated model is sought after at the element-level by adjusting the model's material and/or geometrical properties. Issues such as the normalization brought to the identified parameters, the selection of modal data, the optimal placement of sensors on the structure are addressed and their effects on the model update are demonstrated using real data from different experiments.; Also, a Model Update and Damage Detection Experiment (MUDDE) has been designed in order to demonstrate the performances and limitations of updating methods for recovering structural damage on large flexible space structures. During the MUDDE experiment, every step of the damage detection procedure is controlled from data acquisition, signal conditioning, modal realization, system identification, up to the model update itself. Therefore, the influence of each step on the capability to adjust the model for structural damage in the context of on-orbit identification can be assessed.