Hybrid Stiffened Metal Panel Manufacturing With Machined-Additive Ribs
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Solution Overview
Problem
Current manufacturing processes for aluminum structural elements, such as fuselage panels, are inefficient in terms of material usage and fail to meet mechanical property requirements for critical parts, particularly in aeronautics, due to high labor costs and material wastage in traditional machining methods, and the limitations of additive manufacturing in achieving desired fatigue life and damage tolerance.
Innovation Solution
A method combining classic machining techniques with additive manufacturing, where a base part is machined to form a skin and stiffeners, with additive material being used to extend the stiffeners, optimizing material usage and mechanical properties by reducing the thickness of the base part and improving control over mechanical stresses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If machining from a solid block is used to create structural elements with skin and stiffeners, then the mechanical properties and structural integrity are improved, but material wastage increases significantly
Solution Approach 1:
The manufacturing process is segmented into two distinct operations: first machining the skin and proximal stiffener portion from a reduced-thickness base part, then additively manufacturing the distal stiffener portions. This segmentation allows each process to be optimized for its specific function, minimizing material removal while ensuring structural integrity at critical interfaces.
Solution Approach 2:
The base part thickness parameter is changed from traditional thick blocks to optimized thinner sheets. By reducing the base part thickness and only machining the skin and proximal stiffener portions, material wastage is significantly reduced while the additive manufacturing process compensates to achieve the required final stiffener dimensions and structural properties.
2Loss of substance
If additive manufacturing is used to create the entire structural element including skin and stiffeners, then material usage is optimized, but fatigue resistance and damage tolerance deteriorate
Solution Approach 1:
The structural element is segmented into regions manufactured by different processes: the skin and proximal stiffener portions are machined from a solid base part to ensure high fatigue resistance and damage tolerance at critical load-bearing interfaces, while the distal stiffener portions are additively manufactured to optimize material usage and reduce waste.
Solution Approach 2:
Different manufacturing qualities are applied to different regions of the structural element. The skin and proximal stiffener interfaces, which are critical for fatigue resistance, are manufactured with high precision machining. The distal stiffener portions, which are less critical for fatigue performance, are manufactured additively to optimize material efficiency.
3Loss of substance
If the base part thickness is reduced to minimize material usage, then material wastage decreases, but the ability to machine sufficient stiffener length deteriorates
Solution Approach 1:
The stiffener manufacturing is segmented into two stages: first machining the proximal portion from the base part (even with reduced thickness), then additively manufacturing the distal portion to achieve the required total length. This eliminates the constraint that base part thickness must accommodate the entire stiffener length.
Solution Approach 2:
Additive manufacturing acts as an intermediary process that bridges the gap between the reduced-thickness base part and the required final stiffener length. The additive process adds material to the proximal stiffener portion to extend it to the required distal length, overcoming the limitation of reduced base part thickness.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach reduces material wastage, enhances mechanical property control, and improves the fatigue life and damage tolerance of structural elements, while reducing production costs and labor, allowing for the efficient production of lightweight, high-strength aluminum structural components.
Implementation Method 1
adding material to the end of the stiffener blank formed in step (b), so as to extend the stiffener blank in the extension direction, to obtain a stiffener whose distal end extends to a second extension distance from the internal surface, the second extension distance being greater than 1.5 times the first extension distance, the addition of material being carried out by additive manufacturing, by successively adding elementary layers of material
Data Source
Figure 1A~1G
Figure 2A~2F
Figure 3A~3E
AI summary
The invention relates to a method for the production of a metal structural element from a workpiece, said metal structural element comprising a skin having stiffeners extending therefrom. According to the invention, one portion of the stiffeners is produced by machining, while the other portion is produced by adding material. The material can be added using an additive manufacturing process.