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Collins Aircraft Baggage Door
Structure Optimization
Aircraft subsystems are designed and tested to withstand in-flight and landing conditions, such as
Background
In traditional aircraft doors, the frame consists of multiple metallic extrusions oriented in a grid
pattern. However, Collins Aerospace seeks to improve the design of the baggage door design to
minimize weight, minimizing cost, simplify manufacturability, and maximize performance.
Objective
Collins Aerospace proposed to optimize the current aircraft baggage door design for private jets in terms of stiffness, weight,
cost, and manufacturability. The goal is to design, simulate, fabricate, then physically test a prototype of a proposed stiffener
pattern that would potentially be used as the frame for an aircraft baggage door.
The following requirements are ordered in terms of importance:
1. Material Cost
2. Weight
3. Deflection
The prototype must be able to withstand a pressure gradient of 0.07 MPa across the door, weight no more than 12.84 kg, and
have a maximum bending deflection of 6.35 mm. The functioning prototype will furthermore efficiently output the greatest figure
of merit between quantified moment of inertia and volume.
Baggage Door Constraints
Primary Design Constraints
Maximum Mass: 12.84 kg (28.3 lbs)
Maximum Deflection: 6.35 mm (0.25”)
Door Constraints
Skin Dimensions: 0.9144 m (36 in) x 0.9144 m (36 in) x 0.9144 mm (0.036 in)
Curvature: 20.7˚
Pressure Differential: 0.07 MPa (10.7 psi)
Max Door Design Height: 0.127m (5 in)
Final Design Overview
best possible solution.
involves meeting design requirements, but furthermore optimizing between involved parameters for the
pressure, thermal, and mechanical factors. The goal when designing aircraft components not only
Figure 1: Baggage door design components
The proposed design is lightweight and achieved a 44% mass reduction than the maximum mass constraint. It has a
curvature of 20.7 degrees and uses Al-7050, which is a traditionally used aerospace-grade metal. The door can be manufactured
and assembled using only Al-7050 sheets with a thickness of 0.9144 mm (0.036 in). Since it only uses this type of sheet metal,
the entire door can be made with ease of manufacturability.
There are 3 primary components to the proposed baggage door. The outer skin has dimensions of 0.9144 m (36 in) x 0.9144 m
(36 in) x 0.9144 mm (0.036 in), which serves as the base of the door. The stamp sheet stiffeners maximized the strength and
minimized its weight of the baggage door. The inner skin panels also stiffen the door, while also aligning the stamped sheet
stiffeners into the grid pattern as shown in Figure 1.
FEA Performance on Proposed Design
Figure 2: Displacement Contour of Final CAD Model
The final design underwent a FEA simulation with a pressure gradient of 0.07MPa (10.7psi) applied across it. Under the FEA, 16 contact points were given by Collins Aerospace, which are the locations where the door would be fastened to the fuselage of the aircraft. There are 16 total contact points and were used under the "no penetration" boundary condition. These points are illustrated in the left image in Figure 2. As a result, the deflection profile is illustrated in the right image of Figure 2. According to these results, the proposed design met the mass requirement, but not the deflection criteria.
Experimental Procedure and Results
Figure 3: Experimental Model (1ft x 1ft)
Once the door's deflection from theory and FEA were compared, a physical test was conducted. The deflection of the door was
measured by conducting a 3-point bend test, which utilized three bars. The experimental setup is show in figure 4. The door's
stiffness was tested in two orientations. Such orientations are illustrated below, with Figure 6 referring to the stronger orientation
and Figure 5 showing the weaker orientation. Videos of the test in the weaker and stronger orientations are also provided below in
Video 1 and 2, respectively.
Figure 4: 3-point bend test fixture and setup
Figure 5/Video 1: Physical and FEA displacement profile comparison in the weaker orientation
Experimental Results
Finite Element Analysis
•Load: 399.9 N
•Global Deflection: 5.99 mm
•Failure Criteria: Elastic bending
•Max deflection criteria (6.35mm) occurs at 421.93 N
• With 400 N load:
• Maximum Deflection: 3.93 mm
Figure 6/Video 2: Physical and FEA displacement profile comparison in the stronger orientation
Experimental Results
Finite Element Analysis
•Load: 5997.17 N
•Global deflection: 3.96 mm
•Local deflection depth (Yield Failure) : 20 mm
•Failure criteria: Local Yield Failure
•Local Yield Failure occurs at 11700 N with bar translation of 2.7mm
•With 6000 N load:
•Maximum Global Deflection: 2.45 mm
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