Experimental identification of the nonlinear dynamic behavior of the design of a small space vehicle

Obviously, there are no constructs in nature that describe linear dynamic behavior. However, it is customary to conduct research on such systems, with some exceptions, using the principle of linearization. Nevertheless, with the growth of requirements for modern space technology, a decrease in their mass and size, and a reduction in the time of their ground-based experimental development, it is not permissible not to take into account the nonlinearity in the design, since they become more nonlinear. As you know, rocket and space technology at the stages of transportation to the operating organization, during launch, in orbit, is subjected to dynamic loads. To ensure the smooth operation of space technology, it is necessary to develop the most reliable, that is, accurately describing a full-scale object, a finite element model. It will serve, in turn, for load calculations and strength calculations. This article discusses an experimental study of the nonlinear dynamic behavior of the structure of a small spacecraft. At the initial stage of the work, the amplitude-frequency characteristics of the research object were determined for forward and backward scanning. This approach did not reveal any obvious nonlinearity in the design of the small spacecraft. Then, having previously selected the proposed installation locations for the sensors, a number of experiments were carried out at the resonant frequencies of the small spacecraft, during which the values of the overloads were obtained for different modes of exposure. The results of overloading individual instruments and most of the small spacecraft design did not show convincing nonlinear dynamic behavior. However, experimental data at local locations in the structure revealed a clear non-linear dynamic behavior. These results will serve in the future when validating the finite element model of a small spacecraft for a more reliable determination of the loads on the structure.