Abstract
The fulfilment of the crash is a demanding requirement for a Tiltrotor. Indeed, such a kind of aircraft, being a hybrid between an airplane and a helicopter, inherits the requirements mainly from helicopters (EASA CS 29) due to its hovering ability. In particular, the fuel storage system must be designed in such a manner that it is crash resistant, under prescribed airworthiness requirements, in order to avoid the fuel leakage during such an event, preventing fire and, thus, increasing the survival chances of the crew and the passengers. The present work deals with the evaluation of crashworthiness of the fuel storage system of a Tiltrotor (bladder tank), and, in particular, it aims at describing the adopted numerical approach and some specific results. Crash resistance requirements are considered from the earliest design stages, and for this reason they are mainly addressed from a numerical point of view and by simulations that treat both single components and small/medium size assemblies. The developed numerical models include all the main parts needed for simulating the structural behavior of the investigated wing section: the tank, the structural components of the wing, the fuel sub-systems (fuel lines, probes, etc.) and the fuel itself. During the crash event there are several parts inside the tanks that can come into contact with the tank structure; therefore, it is necessary to evaluate which of these parts can be a damage source for the tank itself and could generate fuel loss. The SPH approach has been adopted to discretise fuel and to estimate the interaction forces with respect to the tank structure. Experimental data were used to calibrate the fuel tank and foam material models and to define the acceleration time-history to be applied. Thanks to the optimized foam’s configuration, the amount of dissipated impact energy is remarkable, and the evaluation of tanks/fuel system stress distribution allows estimating any undesired failure due to a survivable crash event.
Highlights
IntroductionThe numerical simulations, performed with MSC DYTRAN 4.0, were in agreement with the experimental data and allowed setting up the models to be used for the second phase, i.e., a full scale experimental numerical correlation
The specific application to tiltrotors makes this study a reference with respect to fuel storage system development approaches and crashworthiness behaviour knowledge for many reasons: that can be certified without repeating experimental tests
The main focus is on the crashworthiness of the tank structure and structure and by thealso fuel analyzing lines by analyzing damage sources coming from the components the fuel lines damage sources coming from the components installed installed inside the tank
Summary
The numerical simulations, performed with MSC DYTRAN 4.0, were in agreement with the experimental data and allowed setting up the models to be used for the second phase, i.e., a full scale experimental numerical correlation Based on these available tests campaign, the ALE approach was compared to the Lagrangian FE in a work focused on the water impact of a filled tank [10]. The researchers used the simulation in order to provide crashworthy design indications to the fuel tank system before dropping the real test article and lowering the risk of failure of the test itself, which is expensive and requires long term preparation; if it failed, it would have significant impacts on the critical path to the flight of the aircraft.
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
