Undesirable model vibration often occurs in a conventional wind tunnel force test. Large amplitude model vibrations may adversely affect test data and even threaten the safe operation of equipment. It is therefore of great importance to fully understand the mechanism of model vibration occurrence and reduce the vibration amplitude by effective means in wind tunnel tests. This paper first introduces the harms of model vibration, followed by a summary of model vibration types. The progress of reducing model vibrations by various methods are then presented, and the key points and technical difficulties involved in the active control method analyzed. The existing literature shows that the active control method with the piezoelectric stack as the actuator can best meet the requirements of the engineering practice, with better vibration damping effect than others. Finally, suggestions regarding future research on model vibration control in large-scale wind tunnels are presented.

China's maritime territory is vast, and with the increase of Marine activities, the demand for rescue operations in the medium to long-range sea is urgent. The existing rescue system, primarily based on helicopters and ships, has limitations such as short mission range and long response times. Large amphibious aircraft, with its long range, high speed and ability of taking off and landing on the water surface, can conduct fast and effective rescue in medium and long-range sea areas, and is the key aviation equipment for building water rescue force. Among the factors that affect the attendance rate and efficiency of rescue mission, the ability to resist waves is one of the key factors. By studying the requirements of large amphibious aircraft on water rescue mission mode, based on the sea state data of the target sea area of the rescue mission, a process and method of wave resistance demand analysis are established, which can further quantify the wave resistance demand into the design index related to the aircraft's wave resistance ability and provide reference for the development of large water rescue amphibious aircraft and the construction of emergency rescue system.

To address the ill-posedness caused by the inversion of the frequency response function matrix in traditional dynamic load identification methods, as well as the lack of physical interpretability in deep learning methods, a novel Physical Embedded Neural Network (PENN) for dynamic load identification is proposed. By embedding structural dynamic parameters, such as modal mass, modal stiffness, and modal damping, directly into the neural network, the PENN model is constructed to offer physical interpretability. The PENN model can directly identify the power spectral density of dynamic loads through a forward computational process, avoiding the need for inverting the frequency response function matrix as in traditional methods. Additionally, this model can adaptively adjust internal physical parameters, ensuring high-precision identification of dynamic loads even when prior physical parameters are inaccurate. The paper provides a detailed explanation of the method's mechanism, the construction rules of the PENN model, parameter settings, and the training process. Numerical simulations and experimental validations were conducted under various conditions The results show that even when the prior dynamic system parameters are inaccurate and only one training sample is available, the Pearson correlation coefficient of dynamic load identification was consistently above 95%, demonstrating strong robustness and potential for engineering applications.

The magneto-rheological buffer of the landing gear is a semi-active damper designed based on the magneto-rheological effect. It can adjust the damping level of the buffer by varying the current of the exciting coil, thereby alleviating the landing load of the landing gear. We design a magneto-rheological buffer with on-off control and test the circuit dynamic response of the magneto-rheological buffer. To solve the time delay problem of the circuit response, an on-off controller with local negative feedback is proposed and designed to adjust the excitation coil current of the magneto-rheological buffer to alleviate the drop load. The effectiveness of alleviating the landing load is validated through the drop test. The results show that using the on-off control strategy with local negative feedback, we can reduce the peak value of the drop load by 10.3%, compared with the case in which the exciting coil is not energized (i.e., the oleo-pneumatics buffer) .

Flutter is a kind of aeroelastic dynamic stability problem that should be avoided during flight and may lead to disastrous consequences. Ground Flutter Simulation Test (GFST) is an emerging method for flutter testing, which directly uses the prototype structure or model structure of the aircraft as the test object and is a semi-physical simulation test technique. Aerodynamic simulation loading devices, such as shakers, are used to simulate the distributed aerodynamic loads on the structure, so that the aeroelastic stability characteristics of the real structure can be obtained on the ground (outside the wind tunnel). In this paper, the research status of GFST technology is analyzed from three aspects: reduced-order real-time reconstruction of the unsteady aerodynamic, unsteady aerodynamic simulation loading, and implementation of GFST. Future development directions of the GFST technology are also discussed.

The interaction between an elastic structure and electrodynamic shakers commonly exists in Ground Flutter Simulation Tests (GFST) with multi-point excitations, causing a considerable discrepancy between the practical excitation forces and desired ones. To investigate the excitation force characteristics on a cantilever beam excited by a voltage-sourced electrodynamic shaker, the coupled shaker-beam system is modeled to derive the excitation force formula using Hamilton’s principle and Galerkin’s approach. Simulation results using the multi-mode beam model coupled with the shaker model are in good agreement with experimental results, verifying that the proposed multi-mode method can accurately predict the excitation force. Furthermore, parametric studies show that the influence of system parameters on the excitation force is related to the shaker’s operating mode. Unlike in current mode of shaker, when the beam resonant frequency approaches the suspension frequency of shaker armature, the variation of excitation force amplitude in voltage mode is no longer minimal. Meanwhile, if the exciting point in the GFST is located far away from the modal node, it is essential to compensate the force because the accuracy of tests can be reduced dramatically. The coupled shaker-beam model proposed in this paper can provide the basis for compensation measures.