A computational study of the dynamic responses of a composite versus a metallic aircraft fuselage structure in vertical impact along with examination of inclusion of struts and injury prediction of occupants

Abstract

In recent years, the study on crashworthiness of aircraft fuselage section has been of great interest due to the increase in air travel and demand for occupant safety. The FAA conducted a series of drop tests on aircraft fuselage section to determine the structural performance of the airframe and its effect on occupants' injury levels, one such being the drop test of 10-foot long Boeing 737-200 fuselage section at the FAA's William Huges Technical center in 1999. But conducting experimental drop test is not only time consuming but also expensive. In order to overcome this issue, computer modelling and simulations were utilized for efficient and quick investigation of the crashworthiness performance of the aircraft structure. In this study, the LS-DYNA is utilized for the development and reconstruction of a Boeing 737-200 fuselage section FE model as well as the simulations of the drop test impacting a solid surface. The simulated results are correlated with the ones from the actual drop test. The effect of cargo door and fuel tank on the crash performance of the fuselage section are also examined. To improve the crashworthiness of the fuselage section, composite materials are used for the skin of aircraft fuselage section and the corresponding results are compared with those of the metallic skin, as composite material have good strength and reduced weight compared to metallic. A simple design of strut is modeled and its effect on the structural performance is also examined. The MADYMO occupant model is then utilized to simulate and study the injury response of occupants seated on rigid seats in this drop test. The lumbar loads on the occupant are studied as the pelvic region is subjected to impact forces and can have fatal injuries. A simple rigid seat with the Hybrid-III 50th percentile FAA dummy is used to study the lumbar loads for different cases of detailed fuselage and fuselage without fuel tank, when the fuselage has metallic and composite skin. Overall, the study showed that the composite skin having similar thickness compared to metallic could be beneficial in increasing the energy absorption capability of the structure.