Aircraft Sealing Strip Layout for Curved Gap Bending Control
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Solution Overview
Problem
Existing sealing strips for gaps between convexly curved aerodynamic surface elements of aircraft fail to effectively align the neutral fibers of the mid-seal section with the welting sections, leading to detrimental bending effects and reduced aerodynamic performance due to parasitic drag and attachment line discontinuities.
Innovation Solution
A sealing strip design with reduced or omitted welting sections in a specific length region, combined with a stringer-type stiffening structure, aligns the local neutral fibers to match the curvature of the aerodynamic surfaces, enhancing the sealing strip's bending behavior and reducing parasitic drag.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the sealing strip has continuous welting sections along its entire length, then the fixing strength at aerodynamic surface elements is improved, but the bending behavior deteriorates due to misaligned neutral fibers causing detrimental bending effects
Solution Approach 1:
The sealing strip is segmented into three distinct length regions (first, second, and third) with different welting section configurations. The second length region has reduced or omitted welting sections, creating a segmentation that allows different portions of the sealing strip to have different mechanical properties optimized for their specific functions.
Solution Approach 2:
Different regions of the sealing strip are given different local qualities: the first and third length regions have continuous welting sections for strong fixing, while the second length region has reduced or omitted welting sections to allow neutral fiber alignment and proper bending behavior in the curvature-critical middle section.
2Ease of manufacture
If the welting sections have uniform thickness along the entire sealing strip, then the manufacturing simplicity is improved, but the aerodynamic performance deteriorates due to steps and attachment line discontinuities
Solution Approach 1:
The welting sections have varying thickness along the longitudinal direction: thicker in the first and third length regions for strong fixing, and thinner or omitted in the second length region to eliminate steps and attachment line discontinuities, thereby reducing parasitic drag and improving aerodynamic performance.
Solution Approach 2:
The thickness parameter of the welting sections is changed along the longitudinal direction of the sealing strip. The second length region has reduced thickness compared to the first and third regions, creating a gradient that optimizes both aerodynamic performance and structural function.
3Ease of manufacture
If the sealing strip has a simple profile cross-section, then the manufacturing cost is reduced, but the ability to align neutral fibers with curvature deteriorates
Solution Approach 1:
The sealing strip cross-section is segmented into different profile types along its length: regions with continuous profile for structural integrity and regions with interrupted profile for neutral fiber alignment. This segmentation allows the strip to achieve proper curvature adaptation without requiring complex manufacturing throughout the entire length.
Solution Approach 2:
The sealing strip design incorporates dynamic adaptability through variable cross-sections that allow the neutral axis to shift and align with the curvature of the aerodynamic surfaces in the second length region, while maintaining structural stability in the first and third regions through continuous profiles.
Data Source
AI summary
A sealing strip for sealing a gap between convexly curved aerodynamic surface elements of an aircraft. The sealing strip has a convexly curved outer side, welting sections at both longitudinal edges of the sealing strip for fixing the sealing strip at the aerodynamic surface elements, and a mid-seal section between the welting sections. The welting sections protrude on an inner side from the mid-seal section. The sealing strip has a first, second, and third length regions, the second length region being located longitudinally between the first and third length region. The welting sections are omitted in the second length region or the welting sections in the second length region are less rigid than the welting sections in the first and third length regions. Further, a control surface arrangement, a wing and an aircraft with such a sealing strip.