A Novel Design of a Pre-separation Panel Structure to Protect Against the Impact of an Explosion in an Aircraft Plenum Chamber

To reduce the damage of the pressurizing panel structure of a fuselage caused by an explosion at the“least risk bomb location”in an aircraft structure,a new pre-separation panel structure was designed to resist blast loading.First,the dynamic strain response and morphology of impact damage of the new pre-separation panel were measured in an impact damage test.Second,the commercial software LS-DYNA was used to calculate the propagation of the blast shock wave,and the results were compared with empirical equations to verify the rationality of the numerical calculation method.Finally,the fluid–structure coupling method was used to calculate the damage process of the pre-separation panel structure under the impact of an explosion wave and an impact block.The calculated results were in good agreement with the test results,which showed the rationality of the calculation method and the model.The residual strength of the damaged pre-separation panel was significantly higher than that of the original damaged panel.The results show that the new pre-separation panel structure is reasonable and has certain significance for guiding the design of plenum chambers with strong resistance to implosion for aircraft fuselages.

Diffusion and sound absorption properties of the quadratic residue diffuser structure with perforated panel

Acoustic structure study always is the academic research interest. Diffusion ab？sorbing structure（DiflFsorber） has good research value because it has both diflFusion property and sound absorption property. Quadratic residue diffusers（QRD） structure which had good diffusion property was combined with the perforated panel which had good sound absorption property in this study. According to standard AES-4id-2001, the diffusion experiments were carried out to study QRD structure and ones composited with perforated-panels which had1 mm-thickness and perforated percentage of 3%, 5%, 8% respectively. The polar coordinate diagrams of different structure were analyzed to derive the diffusion coefficients. Results showed that the composite structure still had good diffusion performance in the frequency range from100 Hz to 800 Hz. The reflection sound energy of composite structure reduced obviously in the perforated panel resonance frequency range where there was about 2 dB reduction averagely.The study result can provide the reference for the design and development of diifsorber.

Aeroelastic analysis and flutter control of wings and panels:A review

Flutter is a self‐excited vibration under the interaction of the inertial force,aero-dynamic force,and elastic force of the structure.After the flutter occurs,the aircraft structures will exhibit limit cycle oscillation,which will cause catastrophic accidents or fatigue damage to the structures.Therefore,it is of great theoretical and practical significance to study the aeroelastic characteristics and flutter control for improving the aeroelastic stability of aircraft structures.This paper reviews the recent advances in aeroelastic analysis and flutter control of wings and panel structures.The me-chanism of aeroelastic flutter of wings and panels is presented.The research methods of aeroelastic flutter for different structures developed in recent years are briefly summarized.Various control strategies including the linear and nonlinear control algorithms as well as the active flutter control results of wings and panels are presented.Finally,the paper ends with conclusions,which highlight challenges of the development in aeroelastic analysis and flutter control,and provide a brief outlook on the future investigations.This study aims to present a comprehensive under-standing of aeroelastic analysis and flutter control.It can also provide guidance on the design of new wings and panel structures for improving their aeroelastic stability.