The dynamic response of a multi-cabin protective structure subjected to impact load directly affects the protective performance of materials;thus,studying the dynamic response and communication law of wave effect of t...The dynamic response of a multi-cabin protective structure subjected to impact load directly affects the protective performance of materials;thus,studying the dynamic response and communication law of wave effect of the load plays an important role in the prediction of protective performance.In this study,the protection experiments of box-structure under air-and/or water-medium are conducted,the dynamic response of the structure subjected to low-impact load is analyzed,and the corresponding numerical simulations are analyzed using the theory of finite element method(FEM).Combined with experimental and FEM simulations,the shock strain distribution,acceleration attenuation,and signal energy in defensive materials are determined.Based on the results,the metal structure exhibits good absorption characteristics for shock vibration.Using the experimental data,we also show that the attenuation of shock wave in water medium should be significantly better than that in air medium,and the protective structure should be designed for a combination of water and air mediums.Meanwhile,the numerical simulation can provide a quantitative analysis process for dynamic analysis of defensive materials.展开更多
Aiming at the low-frequency pressure fluctuation phenomena in certain liquid oxygen delivery systems during dual engine operation,a numerical study on the intrinsic frequency of the liquid oxygen delivery system was c...Aiming at the low-frequency pressure fluctuation phenomena in certain liquid oxygen delivery systems during dual engine operation,a numerical study on the intrinsic frequency of the liquid oxygen delivery system was conducted by adopting an acoustic unit in Abaqus.Factors such as condensation characteristics of the oxygen-enriched gas gas in the liquid oxygen’s pipeline between pumps,flexibility of the accumulator,and cavitation flexibility of the engine were considered in the simulation models.The simulation results show that the second order frequency of the liquid oxygen delivery system is 8.77 Hz,and the phase difference of the corresponding acoustic modal is 180°,which is the liquid circuit frequency of the small loop between the two branches of the tee.This is consistent with the low-frequency fluctuation phenomenon during flight.Moreover,the simulation results were consistent with the liquid circuit frequency solved via the transfer matrix,which also verified the effectiveness of the frequency analysis method based on acoustic theory.展开更多
基金supported by the Natural Science Foundation of Heilongjiang Province,China(LH2019A008)the National Natural Science Foundation of China(51508123,named‘Study on blast response of floating roof storage tank in material point method’).
文摘The dynamic response of a multi-cabin protective structure subjected to impact load directly affects the protective performance of materials;thus,studying the dynamic response and communication law of wave effect of the load plays an important role in the prediction of protective performance.In this study,the protection experiments of box-structure under air-and/or water-medium are conducted,the dynamic response of the structure subjected to low-impact load is analyzed,and the corresponding numerical simulations are analyzed using the theory of finite element method(FEM).Combined with experimental and FEM simulations,the shock strain distribution,acceleration attenuation,and signal energy in defensive materials are determined.Based on the results,the metal structure exhibits good absorption characteristics for shock vibration.Using the experimental data,we also show that the attenuation of shock wave in water medium should be significantly better than that in air medium,and the protective structure should be designed for a combination of water and air mediums.Meanwhile,the numerical simulation can provide a quantitative analysis process for dynamic analysis of defensive materials.
文摘Aiming at the low-frequency pressure fluctuation phenomena in certain liquid oxygen delivery systems during dual engine operation,a numerical study on the intrinsic frequency of the liquid oxygen delivery system was conducted by adopting an acoustic unit in Abaqus.Factors such as condensation characteristics of the oxygen-enriched gas gas in the liquid oxygen’s pipeline between pumps,flexibility of the accumulator,and cavitation flexibility of the engine were considered in the simulation models.The simulation results show that the second order frequency of the liquid oxygen delivery system is 8.77 Hz,and the phase difference of the corresponding acoustic modal is 180°,which is the liquid circuit frequency of the small loop between the two branches of the tee.This is consistent with the low-frequency fluctuation phenomenon during flight.Moreover,the simulation results were consistent with the liquid circuit frequency solved via the transfer matrix,which also verified the effectiveness of the frequency analysis method based on acoustic theory.
