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Luo H.,Beihang University | Yan Y.,Beihang University | Meng X.,Beihang University | Jin C.,Beihang University | Wen Y.,Corporation of Harbin Aircraft Industry Group
Fuhe Cailiao Xuebao/Acta Materiae Compositae Sinica | Year: 2015

After the 7.9 m/s vertical drop anti-crash simulation of a full scale composite fuselage structure with energy-absorbing subfloor, the corresponding dynamic impact parameters of the average acceleration, velocity and impact force of the structure were obtained. Different assessment methods were considered to evaluate the crashworthiness characteristics of the structure. The full scale composite fuselage structure was divided into different sections in the design, and the energy-absorbing foam was added into the bottom structure of the fuselage section. The calculated results indicate that the crashworthiness design can meet the corresponding specifications. The impact simulation was carried out using the professional nonlinear explicit transient dynamic finite element software. Compared with the test results, the calculated average acceleration does not exceed 13 g, with the relative error being less than 11%. The maximum vertical impact load is less than 6 kN, and the persistent time of the average minus acceleration of crash is not more than 0.03 s. All these results are reasonable. The model can be used for the anti-crash design of the helicopter. ©, 2015, Beijing University of Aeronautics and Astronautics (BUAA). All right reserved.

Luo H.,Beihang University | Yan Y.,Beihang University | Meng X.,Beihang University | Liang Z.,Beihang University | And 2 more authors.
Beijing Hangkong Hangtian Daxue Xuebao/Journal of Beijing University of Aeronautics and Astronautics | Year: 2014

The experimental crashworthiness research on energy-absorbing discrete structures of composite was carried out. The corresponding energy absorption load-displacement curves, the average load, the peak load and the total energy-absorbing parameters were all obtained. Considering the anisotropic constitutive relation of composites, the secondary development of the finite element software was applied. Considering the Hashin failure criterion with the stiffness degradation theory included, the progressive failure numerical analysis was discussed for the structural discreteness. Based on the extended failure criterion, a gradually weakness of layup triggers links style was set up respectively, also the average load of energy-absorbing evaluation parameter was obtained by numerical simulation, which is 361.10 kN. Compared with the experimental results, the relative error is less than 7%, and the numerical simulation results agree well with those of the experiments, which indicate the feasibility and effectiveness of this method to estimate the crashworthiness of composite structural discreteness.

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