Extracting Time-Varying Dynamic Characteristics of a Typical TPS Plate via Thermal-Vibration Experiment

Extracting time-varying dynamic characteristics of an aerospace structure under thermal-vibration environment is difficult and complicated since the material properties of the structure fluctuate although the external load is constant. Initially, a composite plate model applied for time-varying system is updated based on finite strip method. Afterward, a thermal-vibration experimental system for realizing high-precision data measurement is designed, and the preliminary experiment certified the validity of experimental method. Finally, the time-varying dynamic characteristics of a typical thermal protective system plate is researched. Results show that the natural frequencies take a downward tendency with respect to heating time, and will undergo a dramatic decrease when the structure reaches the critical bulking temperature, while the damping characteristic shows an adverse trend. In addition, for certifying the applicability and accuracy of the updated model, comparisons between present model and recursive subspace method are conducted. The purpose of this paper is to provide some references on evaluating stability for aerospace structures under severe flight environment.