محمدجواد چیتگری

This paper deals with active vibration control (AVC) and structural health monitoring of a maneuvering flexible spacecraft with a cracked panel using piezoelectric (PZT) sensor/actuator patches and strain rate feedback (SRF) method. The cracked panel is modeled using the Euler-Bernoulli beam theory and the finite element method (FEM). The nonlinear equations of motion of the fully coupled rigid-flexible system are extracted using the Lagrangian formulation and solved with Newmark-β algorithm. Two approaches of structural health monitoring; first, trial and error, and second, maximum strain rates (online measurement) along with AVC (applying control signals based on the maximum values of strain rates to the predefined number, but unknown locations of PZT actuators), are performed. The strain rates change directly with mission conditions and crack locations, and the corresponding actuators are activated simultaneously. Moreover, to identify the dynamic behavior of the whole, cracked system, an energy function with different weighting coefficients is introduced to propose a suitable criterion for the performance evaluation of the second approach. Simulations for different crack numbers and locations and external disturbances as a comparative study (in MATLAB/Simulink) demonstrate suitable criteria to determine the number and locations of actuators and reduce the power costs in modern spacecraft in high-precision missions.