Impact Testing and Simulation of a Crashworthy Composite Fuselage Section with Energy-Absorbing Seats and Dummies (original) (raw)
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Multi-Terrain Impact Tests and Simulations of an Energy Absorbing Fuselage Section
Journal of the American Helicopter Society, 2007
Comparisons of the impact performance of a 5-ft diameter crashworthy composite fuselage section were investigated for hard surface, soft soil, and water impacts. The fuselage concept, which was originally designed for impacts onto a hard surface only, consisted of a stiff upper cabin, load bearing floor, and an energy absorbing subfloor. Vertical drop tests were performed at 25-ft/s onto concrete, soft-soil, and water at NASA Langley Research Center. Comparisons of the peak acceleration values, pulse durations, and onset rates were evaluated for each test at specific locations on the fuselage. In addition to comparisons of the experimental results, dynamic finite element models were developed to simulate each impact condition. Once validated, these models can be used to evaluate the dynamic behavior of subfloor components for improved crash protection for hard surface, soft soil, and water impacts.
CRASH SIMULATION OF A 1/5SCALE MODEL COMPOSITE FUSELAGE CONCEPT
2000
This paper describes the MSC/DYTRAN crash simulation of a 1/5-scale model composite fuselage concept, which was developed to satisfy structural and flight loads requirements and to satisfy design goals for improved crashworthiness. The fuselage consists of a relatively rigid upper section which forms the passenger cabin, a stiff structural floor, and an energy absorbing subfloor which is designed to limit
An overview of the failure behavior results is presented from some of the crash dynamics research conducted with concepts of aircraft elements and substructure not necessarily designed or optimized for energy absorption or crash loading considerations. To achieve desired new designs which incorporate improved energy absorption capabilities often requires an understanding of how more conventional designs behave under crash type loadings. Experimental and analytical data are presented which indicate some general trends in the failure behavior of a class of composite structures which include fuselage panels, fuselage sections, individual fuselage frames, skeleton subfloors with stringers and floor beams without skin covering, and subfloors with skin added to the frame-stringer structure. Although the behavior is complex, a strong similarity in the static/dynamic failure behavior among these structures is illustrated through photographs of the experimental results and through analytical...
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: This research aims to develop, analyze, and evaluate a new type of structural element that will enhance the crashworthiness of naval vehicles by providing outstanding energy absorption with minimal weight. The structural element is an array of concentric fiber reinforced composite tubes with extension-twist coupling and ultra-high Poisson's ratio. The tubes are configured to crush or shear internal foam as a means of absorbing energy. This interim report includes technical progress, plans, publications, and various administrative matters. In the current period, work has focused on evaluating the mechanisms of energy absorption in composite tubular structures and the development of analytical models for predicting the deformation and damage in these tubular structures. A significant effort was dedicated towards developing the manufacturing and testing technology for tubes having extension-twist coupling. This effort culminated in the successful demonstration, for the first time...
2020
The following research studies and enhances the structures from a commercial aircraft fuselage section by implementing crushable energy absorbers as vertical struts. The previously-developed numerical simulation from the drop test of a Boeing 737-200 is used, both featuring and lacking the auxiliary fuel tank, with the latter offering a more harmful response. Five crushable absorbers were then added to the cargo compartment connecting the frames with the underfloor beams seeking the modification of the collapse mechanism of the aircraft and, consequently, a more progressive and safer behavior. The results obtained show a reduction of the acceleration peaks by over 50% when the absorbers are fitted in the section without a fuel tank. Moreover, the acceleration plots in the Eiband diagram also reveal a reduction of the passenger injury assessment from severe to moderate. An in-depth analysis of the energy values during the simulation shows an energy absorption of 25 kJ from the absorb...
Efforts in the Standardization of Composite Materials Crashworthiness Energy Absorption
2000
One of the key factors preventing the widespread adoption of composites in primary crash structures is the absence of specialized test methods for the characterization of specific energy absorption (SEA). Aside from thin-walled tubular specimens, a limited number of attempts have been made at developing test specimens that are easier to manufacture. The possibility to employ a self-stabilizing corrugated plate
Numerical Simulation Of Composite StructuresUnder Impact
1970
Within the European research program 'Design for Crash Survivability', CRASURV [1], simulation of the crash behavior of aircraft subfloor components, like sine-wave beams and 'tensor skin' panels, is performed by Univ. Patras. These substructures, which are made of composite materials, were initially developed by NLR and originally suggested in [2] and [3], as energy absorbing elements in helicopter subfloor structures subjected to water impact The practical application of the 'tensor skin' concept was found in a sandwich corrugated panel configuration. In order to identify their ability to transfer impact loads and absorb impact energy, preliminary static crush tests were performed in one and two-dimensional strips, as well as, in three-dimensional square panels. In the present paper, the modeling methodology of these crashworthiness substructures, using the Finite Element (FE) technique, is described. Numerical simulations of selected initial proof tests of...
Energy Absorbing Sacrificial Structures Made of Composite Materials for Vehicle Crash Design
Solid Mechanics and Its Applications, 2012
Nowadays thin-walled components in CFRP composite materials are considered in order to progressively replace metals for crashworthy applications in the automotive industry, thanks to their undoubted advantages such as high strength to weight ratio. The present chapter is dealing with the lightweight design and the crashworthiness analysis of a composite nose cone as the Formula SAE racing car front impact attenuator. The analysis of the crash behaviour was conducted both numerically, using explicit FE codes as LS-DYNA and Radioss, and experimentally, by means of a drop weight test machine. In order to assess the quality of the simulation results, initially a complete comparative analysis with material characterization was developed on simple CFRP composite tubes subjected to dynamic axial impact loading. After quasi-static and dynamic experimental crash tests on the composite nose cone were performed. These experimental results are reported together with numerical simulation ones. The main idea of the research was to demonstrate energy absorbing capabilities of a thin-walled crash box during the frontal impact, with the lowest initial deceleration. In order to initialize the collapse in a stable way, the design of the composite impact attenuator has been completed with a trigger which consists of a very simple smoothing (progressive reduction) of the wall thickness. Initial requirements were set in accordance with the 2008 Formula SAE rules and they were satisfied with the final configuration.
2012
In November 2000, a vertical drop test of a Boeing 737 airplane fuselage section was conducted at the Federal Aviation Administration (FAA) William J. Hughes Technical Center, Atlantic City International Airport, New Jersey. The intent was to determine the impact response of a narrow-body airplane fuselage section, including the response of the airframe structure and cabin items of mass. The purpose of this study was to develop a finite element model to simulate the vertical drop test of that fuselage section. The 10-foot-long test section included 18 seats occupied by dummy passengers, luggage stowed in the cargo compartment beneath the floor, and two different FAA-certified overhead stowage bins. The test article was dropped from a 14-foot height, resulting in a vertical impact velocity of 30 ft/sec. The primary goal of this drop test was to characterize the behavior of the two overhead bins under a severe, but survivable, impact condition.