PI-Control Hybrid Fire Testing with Force-Controlled Procedure

The present contribution deals with the possibility of using the PI-Control method in order to perform a Hybrid Fire Test (HFT) with a force-controlled procedure (FCP). Such a method may be applied in two ways where the instantaneous error is calculated in term of displacement or in term of force. Like the displacement-controlled procedure (DCP), stability of the HFT results can be ensured by an appropriate design of the values of the gains matrix, which depends on the estimation of the initial stiffness of the Physical Substructure (PS) as well as the chosen value of the eigenvalues. This paper will demonstrate how it is possible to determine optimal parameters in order to ensure the stability of a HFT when using such a method. In addition, it will be shown that, on the contrary to the recommendations for the use of the PI-Control method with the DCP, the initial stiffness of the PS should be underestimated rather than overestimated when the FCP is used. For illustrative purpose, several virtual HFTs have been implemented and analysed.