In this paper, a concise and universal method to calculate the maximum RF (radio frequency) power transfer efficiency between arbitrary multiple transmitters and multiple receivers wireless power transfer (MIMO-WPT) system is presented. The method is based on maximum Rayleigh quotient which can be deduced either from the multi-port impedance matrix Z or from the multi-port scattering matrix S. Moreover, without any limitation on the transmitting/receiving element's geometry, numbers, operating frequency, coupling method, and so on, the approach is capable to evaluate both the transfer efficiency and the maximum transfer efficiency (MTE) of any type of transmitting and receiving elements, and to obtain the optimum impedances for all transmitting or receiving ports as well. At the end of this paper, the MTEs of some typical MIMO-WPT systems will be calculated to validify the proposed method, and the effectiveness against the receiver's misalignment by using multiple transmitters will be demonstrated.

Predicting the dynamic behavior of laminated rotors in bending requires theidentification of the bending rigidity of the laminated core. An identification ofconstitutive properties is proposed on the rotor at rest, which is a first step forrotordynamics prediction. Modal parameters predicted and measured are included in afunctional based on a hybrid Rayleigh quotient and combined with the Guyan method, themaster degrees of freedom corresponding to the measurement points. The laminated corerigidity is extracted through a Levenberg-Marquardt minimization.