Wing Panel Peen Forming with Neutral Axis Shift
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Solution Overview
Problem
The peen forming method for curvedly forming aircraft wing panels results in insufficient curvature, particularly around engine attachments, requiring excessive time and demanding improved formability.
Innovation Solution
A wing panel design featuring a rib with a width-expanded base end portion and a neutral axis positioned on the wing panel side, allowing metal shots to project and deform the rib, enhancing curvature and formability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If the peen forming method is used to curve the wing panel, then the wing panel can be formed into a three-dimensional shape, but the radius of curvature is too large and the curvature is insufficient, especially around engine attachment areas
Solution Approach 1:
The stringer member is designed with a thickness-expanded part at the base end portion, creating local variation in thickness. This local quality change concentrates the strain moment at the base end portion during peen forming, enabling sufficient curvature in specific areas (around engine attachment) without requiring excessive forming time across the entire wing panel.
Solution Approach 2:
The neutral axis position is deliberately positioned on the wing panel side from the center of the stringer member height. This parameter change in the geometric configuration of the stringer member alters the strain distribution during peen forming, concentrating deformation at the base end portion and improving curvature efficiency.
2Productivity
If metal shots are projected to the tip end part of the stringer member to form curvature, then the wing panel can be curved, but the forming process requires excessive time due to insufficient curvature achievement
Solution Approach 1:
By expanding the thickness at the base end portion of the stringer member, the design creates a localized region with different mechanical properties. This allows the peen forming process to achieve the required curvature more quickly by concentrating the forming action at this strategic location rather than requiring uniform forming across the entire stringer length.
Solution Approach 2:
The stringer member is pre-configured with a specific neutral axis position and thickness distribution before the peen forming process. This preliminary structural preparation ensures that when metal shots are projected, the strain moment is automatically concentrated at the base end portion, accelerating the curvature formation process.
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
The design improves formability by distributing strain moments effectively, enabling efficient curvature even with small radii of curvature, reducing forming time and improving wing panel shaping.
Implementation Method 1
metal shots are projected to the tip end portion of the rib, the wing panel body is curvedly formed
Implementation Method 2
the surface of a portion with which the metal shots collide, and the wing panel is curvedly formed by the difference in arc length
Data Source
AI summary
There is provided a wing panel having improved formability at the time when the wing panel is curvedly formed by the peen forming method, and an aircraft main wing provided with the said wing panel. For a stringer member 20, a base part 21 is formed, and the neutral axis position N in the cross-sectional direction is located on the wing panel 11 side from the center position C in the height direction of a web part 22. When the peen forming method is carried out by projecting metal shots to a portion near a flange part 23 in the tip end portion of the stringer member 20, the tensile strain developing in the portion near a flange part 23 acts in a state in which the moment length around the neutral axis position N is kept long.