DELAY-DEPENDENT STABILITY ANALYSIS OF REAL-TIME DYNAMIC HYBRID TESTING

The basic principle and research progress of real-time dynamic hybrid testing (RTDHT) are presented. The mathematical model of SDOF RTDHT is established based on the pure delay assumption of a transfer system. The root locus analysis method based on Padé decomposition approximating the delay item is employed to obtain the delay-dependent stability conditions of SDOF real-time dynamic hybrid testing. The results show that the single upper stability limits of the mass, damping and stiffness vary quasi-periodically with both the natural frequency of structure and the transfer system response delay; these limits decrease as both the natural frequency and delay increase for a low frequency structure; for the compound stability condition of the case where the experimental substructure contains mass, damping and stiffness simultaneously, both an upper and a lower mass boundaries may exit. A numerical model is built to validate the theoretical stability condition.