Emmanuel Detaille, Chief Technology Officer, Coexpair
Q1: You are involved in the activities aiming to check the feasibility and to manufacture new structural concepts of the landing gear doors to reduce vibration levels. Could you please explain us the work performed to develop the new design of the Nose Landing Gear Door (NLGD)?
A1: Coexpair & SLCA are currently working on the design of the NLGD (i.e. frontward door as shown on figure 18). The objective is to replace the current sandwich NLGD by a monolithic structure for flight test.
Some major development steps have been identified to meet the objectives defined at the beginning of AFLoNext project :
The current design proposals are based on both the load cases and Interface Control Drawings (ICD) provided by Airbus Spain and the background from previous IMS&CPS project (see figure 19):
Step 1 – Concept generation
Step 2 – Final design based on selected NLGD concept (see figure 20).
Q2: What were the criteria for selection of the final NLGD concept?
A2: As described previously, the ranking of all generated concepts has been operated in three main families on the basis of a trade-off conducted with several criteria : technical (inspectability, withstand load cases…), production (suitability for potential serial production), Aflonext requirements (time schedule with respect to flight test).
Q3: What are the stakes of the Finite Element Model (FEM) analysis?
A3: There are several stakes:
1. Functionality – Check similar global stiffness of the new NLGD to be able to close both the doors during the test.
2. Safety – Check no delamination propagation under ultimate loads (1.5 times the maximum load ever seen during all the life of the aircraft) & check no failure of the door (in case of door actuation failure). This method is similar to certification for parts for serial production, the difference is that in this case, as the door will fly only a few dozens of minutes (and not for several years), the qualification process near the authorities for the flight test will not require, for example, fatigue tests (tests used to show that a part can withstand a load several dozens of thousands of time over several years).
Q4: What can you tell us about the manufacturing process that will be used i.e. the Same Qualified Resin Transfer Moulding (SQRTM)?
A4: SQRTM is a robust alternative to Autoclave combining advantages of RTM (closed mold process) with advantages of autoclave (high toughness resins)
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