PSI - Issue 24

Francesco Caputo et al. / Procedia Structural Integrity 24 (2019) 788–799 M. Manzo / Structural Integrity Procedia 00 (2019) 000 – 000

798

11

5. Final considerations

In this work, the reliability of a developed FE model, previously validated respect to a pure vertical drop test case, has been assessed under a combined impact load condition. The results obtained indicate that the presence of horizontal velocity component of 20 m/s, in addition to the pure vertical component of 9.14 m/s, causes accelerations and loads transmitted to the passenger area much higher than a pure vertical velocity case and, therefore, much more dangers for the safety of occupants. In particular, skin, struts and floor beams result markedly damaged and more damages affect the passengers’ floor as well. In the end, the finite element model has proved to be appropriate and effective also to simulate more critical impact conditions, providing realistic results, which are consistent respect to the reference data. Future developments could lead a better characterization of the FE model to perform the falling with oblique trajectory in a more realistic way with respect to experimental tests, i.e. taking into account the remaining part of the fuselage in order to simulate an entire aircraft drop test.

Acknowledgements

The study has been funded in the framework of Italian Minister Research Program PON 2007-2013 through the POR - FESR funds managed by Regione Campania, promoted by DAC (Distretto Aerospaziale della Campania), within the CERVIA (Innovative and Advanced Verification and CERtification methods) project, in partnership with CIRA SCpA and coordinated by Leonardo Aircraft Division. The authors would like to acknowledge all the involved partners.

References

Annett, M.S., 2015. Evaluation of the Second Transport Rotorcraft Airframe Crash Testbed (TRACT 2) Full Scale Crash Test. 71st AHS (American Helicopter Society) International Annual Forum, Virginia Beach, VA, United States. Annett , M.S., Littell , J.D., Jackson , K.E., Bark , L., DeWeese , R., McEntire , B.J., 2014. Evaluation of the First Transport Rotorcraft Airframe Crash Testbed (TRACT 1) Full-Scale Crash Test. NASA Technical Memorandum, NASA/TM-2014-218543, L-20469, NF1676L-19694 . Annett, M.S., Littell, J.D., Stimson, C.M., Jackson, K.E., Mason, B.H., 2016. Full-Scale Crash Tests and Analyses of Three High-Wing Single Engine Aircraft. NASA Technical Memorandum, NF1676L-21536, Aerospace Structural Impact Dynamics International Conference (ASAIDIC), Seville, Spain. Caputo, F., De Luca, A., Greco, A., Maietta, S., Marro, A., Apicella, A., 2018. Investigation on the static and dynamic behaviours of a regional aircraft main landing gear by a new numerical methodology. Frattura ed Integrità strutturale 12, 191-204. Caputo, F., De Luca, A., Greco, A., Marro, A., Apicella, A., Sepe, R., Armentani, E., 2018. Established numerical techniques for the structural analysis of a regional aircraft landing gear. Advances in Material Science and Engineering, Volume 2018. Caputo, F., Lamanna, G., De Luca, A., Lopresto, V., 2014. Numerical simulation of LVI test onto composite plates. American Institute of Physics (AIP) Conference Proceedings 1599, 334. Caputo, F., Lamanna, G., Soprano, A., 2011. Numerical Modeling and Simulation of a Bolted Hybrid Joint. Structural Durability & Health Monitoring (SDHM) 7(4), 283-296. CS-25, “Certification Specifications and Acceptable Means of Compliance for Large Aeroplanes”, EASA (European Aviation Safety Agency), Amendment 15, 21 July 2014. De Luca, A., Sharif-Khodaei, Z., Aliabadi, M.H., Caputo, F., 2016. Numerical Simulation of the Lamb Wave Propagation in Impacted CFRP Laminate. Procedia Engineering 167, 109–115. Federal Aviation Administration FAA, Code of Federal Regulation 14, Part 25, Subpart C. Structure. Federal Aviation Regulation FAR 25.562, 2006. Emergency landing dynamic conditions. Federal Aviation Administration FAA. Guida, M., Marulo, F., Abrate, S., 2018. Advances in crash dynamics for aircraft safety. Progress in Aerospace Sciences 98, 106-123. Jackson, K. E., Fasanella, E.L., Littell J.D., Annett M.S., Stimson C.M., 2017. Simulating the Impact Response of Three Full-Scale Crash Tests of Cessna 172 Aircraft. NASA Technical Memorandum, NASA/TM–2017-219599. Jackson, K. E., Fasanella, E.L., Lyle, K.H., 2006. Crash Certification by Analysis – Are We There Yet? American Helicopter Society 62nd Annual Forum, Phoenix, AZ, United States. Littell J.D., 2018. Full-Scale Drop Test of a Fokker F28 Wingbox Fuselage Section. Earth and Space 2018: Engineering for Extreme Environments. Littell, J.D., Annett M.S., 2016. ATD Occupant Responses from Three Full-Scale General Aviation Crash Tests. NASA Technical Memorandum, NASA/TM–2016-219175. Littell, J.D., Jackson, K.E., Annett, M.S., Seal, M.D., Fasanella, E. L., 2016. The Development of Two Composite Energy Absorbers for Use in a Transport Rotorcraft Airframe Crash Testbed (TRACT2) Full-Scale Crash Test. Annual Forum Proceedings - AHS International 2, 984-1001. Ls-Dyna® R7.1, Keyword User's Manual, May 26, 2014 (revision: 5471), Livermore Software Technology Corporation (LSTC), P. O. Box 712 Livermore, California 94551-0712.