According to relevant airworthiness standards, the aircraft fuel tank access cover must withstand the impact by tire fragments, and minimize the penetration and deformation, which is critical for flight safety. To ass...According to relevant airworthiness standards, the aircraft fuel tank access cover must withstand the impact by tire fragments, and minimize the penetration and deformation, which is critical for flight safety. To assess the safety of an aircraft fuel tank access cover subjected to tire fragments, a study of dynamic response was presented in this paper using the Finite element(FE) software ANSYS/LS-DYNA. To obtain the reliable mechanical characteristics of tire tread rubber, a series of material tests have been conducted. Then the proposed rubber material model is validated by comparing the numerical simulations with the experimental results of aluminium alloy plate impact. The simulation results indicate that the rubber fragment and alloy plate will undergo the largest deformation when impact angle is equal to 90°. Finally, the proposed FE model and modelling approaches are extended to the numerical simulation of a full-scale aircraft fuel tank access cover impact. The numerical simulations are carried out with impact velocity of 71.1 m/s and impact angle of 40.5°. The simulation results indicate that the aluminium alloy by precision casting is more likely to rupture, and the middle region of the access cover is vulnerable to fragment impact. This research proposes a reliable rubber model applying to various strain rates. Considering the influence of impact regions, the dynamic response and various failure patterns of fuel tank access cover are acquired. The findings of this paper can be used to improve the future aircraft safety design.展开更多
The process of the gas jet from aircraft engines impacting a jet blast deflector is not only a complex fluid–solid coupling problem that is not easy to compute, but also a safety issue that seriously interferes with ...The process of the gas jet from aircraft engines impacting a jet blast deflector is not only a complex fluid–solid coupling problem that is not easy to compute, but also a safety issue that seriously interferes with flight deck envi?ronment. The computational fluid dynamics(CFD) method is used to simulate numerically the impact e ect of gas jet from aircraft engines on a jet blast deflector by using the Reynolds?averaged Navier?Stokes(RANS) equations and turbulence models. First of all, during the pre?processing of numerical computation, a sub?domains hybrid meshing scheme is adopted to reduce mesh number and improve mesh quality. Then, four di erent turbulence models includ?ing shear?stress transport(SST) k-w, standard k-w, standard k-ε and Reynolds stress model(RSM) are used to compare and verify the correctness of numerical methods for gas jet from a single aircraft engine. The predicted values are in good agreement with the experimental data, and the distribution and regularity of shock wave, velocity, pressure and temperature of a single aircraft engine are got. The results show that SST k?w turbulence model is more suitable for the numerical simulation of compressible viscous gas jet with high prediction accuracy. Finally, the impact e ect of gas jet from two aircraft engines on a jet blast deflector is analyzed based on the above numerical method, not only the flow parameters of gas jet and the interaction regularity between gas jet and the jet blast deflector are got, but also the thermal shock properties and dynamic impact characteristics of gas jet impacting the jet blast deflector are got. So the dangerous activity area of crew and equipments on the flight deck can be predicted qualitatively and quantitatively. The proposed research explores out a correct numerical method for the fluid–solid interaction during the impact process of supersonic gas jet, which provides an e ective technical support for design, thermal ablation and structural damage analysis of a new jet blast deflector.展开更多
基金Supported by Research Fund for the Doctoral Program of Higher Education of China(Grant No.20136102120031)National Science Foundation of China(Grant No.51805150)
文摘According to relevant airworthiness standards, the aircraft fuel tank access cover must withstand the impact by tire fragments, and minimize the penetration and deformation, which is critical for flight safety. To assess the safety of an aircraft fuel tank access cover subjected to tire fragments, a study of dynamic response was presented in this paper using the Finite element(FE) software ANSYS/LS-DYNA. To obtain the reliable mechanical characteristics of tire tread rubber, a series of material tests have been conducted. Then the proposed rubber material model is validated by comparing the numerical simulations with the experimental results of aluminium alloy plate impact. The simulation results indicate that the rubber fragment and alloy plate will undergo the largest deformation when impact angle is equal to 90°. Finally, the proposed FE model and modelling approaches are extended to the numerical simulation of a full-scale aircraft fuel tank access cover impact. The numerical simulations are carried out with impact velocity of 71.1 m/s and impact angle of 40.5°. The simulation results indicate that the aluminium alloy by precision casting is more likely to rupture, and the middle region of the access cover is vulnerable to fragment impact. This research proposes a reliable rubber model applying to various strain rates. Considering the influence of impact regions, the dynamic response and various failure patterns of fuel tank access cover are acquired. The findings of this paper can be used to improve the future aircraft safety design.
基金Supported by National Natural Science Foundation of China(Grant No.51505491)Shandong Provincial Natural Science Foundation of China(Grant No.ZR2014EEP019)
文摘The process of the gas jet from aircraft engines impacting a jet blast deflector is not only a complex fluid–solid coupling problem that is not easy to compute, but also a safety issue that seriously interferes with flight deck envi?ronment. The computational fluid dynamics(CFD) method is used to simulate numerically the impact e ect of gas jet from aircraft engines on a jet blast deflector by using the Reynolds?averaged Navier?Stokes(RANS) equations and turbulence models. First of all, during the pre?processing of numerical computation, a sub?domains hybrid meshing scheme is adopted to reduce mesh number and improve mesh quality. Then, four di erent turbulence models includ?ing shear?stress transport(SST) k-w, standard k-w, standard k-ε and Reynolds stress model(RSM) are used to compare and verify the correctness of numerical methods for gas jet from a single aircraft engine. The predicted values are in good agreement with the experimental data, and the distribution and regularity of shock wave, velocity, pressure and temperature of a single aircraft engine are got. The results show that SST k?w turbulence model is more suitable for the numerical simulation of compressible viscous gas jet with high prediction accuracy. Finally, the impact e ect of gas jet from two aircraft engines on a jet blast deflector is analyzed based on the above numerical method, not only the flow parameters of gas jet and the interaction regularity between gas jet and the jet blast deflector are got, but also the thermal shock properties and dynamic impact characteristics of gas jet impacting the jet blast deflector are got. So the dangerous activity area of crew and equipments on the flight deck can be predicted qualitatively and quantitatively. The proposed research explores out a correct numerical method for the fluid–solid interaction during the impact process of supersonic gas jet, which provides an e ective technical support for design, thermal ablation and structural damage analysis of a new jet blast deflector.
