Airplane Wing Rib Stiffness via Reinforcing Beads
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Solution Overview
Problem
The existing airplane wing structures face issues with rib deformation during rivet hole machining due to drilling loads, leading to precision degradation and potential repair needs, which increase machining costs.
Innovation Solution
The implementation of a rib structure with a mounting flange secured to the skin via a rivet, featuring first and second cutouts and a reinforcing bead that extends along the stringer through hole and cutouts, enhancing vertical load stiffness and eliminating the need for deformation prevention jigs and repair operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If a rib is formed from thin plate material to lighten weight, then weight is reduced, but the rib may buckle under shear load
Solution Approach 1:
The patent applies local quality by forming a bead structure at specific locations on the rib (along the mounting flange and through the stringer through hole) rather than uniformly thickening the entire rib. This localized reinforcement increases buckling strength where needed while maintaining overall lightweight construction.
Solution Approach 2:
The patent transitions from a two-dimensional thin plate rib to a three-dimensional structure by adding a bead that protrudes from the rib surface. This dimensional change creates additional structural stiffness and buckling resistance without significantly increasing weight.
2Strength
If a rib is formed with a bead to enhance buckling strength, then strength is improved, but the rib may deform during machining operations
Solution Approach 1:
The bead is formed on the rib before the rivet hole machining operation. This preliminary formation of the reinforcing structure provides stiffness that prevents deformation during subsequent machining, eliminating the need for deformation-prevention jigs.
Solution Approach 2:
The rib structure is segmented into different functional zones: the bead provides reinforcement, the mounting flange provides attachment surface, and the stringer through hole accommodates stringers. This segmentation allows each part to perform its specific function optimally.
3Ease of manufacture
If drilling is performed on a rib without sufficient stiffness, then machining is simpler, but the rivet hole may not be formed as a true circle
Solution Approach 1:
The bead structure is formed in advance to counteract the deforming effect of drilling loads. This preliminary anti-action prevents the rib from deforming during rivet hole machining, ensuring true circular holes are formed without requiring complex machining setups.
4Productivity
If the entire rib is curved due to drilling load, then repair operations are needed, but this increases cost and time
Solution Approach 1:
The bead is formed before machining to prevent deformation during drilling. This preliminary reinforcement action eliminates the need for repair operations, maintaining both productivity and structural integrity.
Data Source
AI summary
A rib of an airplane wing is prevented from deforming due to a machining load when machining a rivet hole in parts where the rib and a skin are joined. With regard to a rib that provides a connection between first and second spars of the airplane wing, the rib is formed with mounting flanges secured to a skin via a rivet, a stringer through hole for a stringer to be positioned through, and first and second cutouts facing parts where the first and second spars and the skin are connected. Since reinforcing beads are formed along the mounting flanges and reinforcing flanges are formed so as to extend in the span direction from the edges of the stringer through hole and the first and second cutouts and be connected integrally to the mounting flanges, the stiffness of the rib toward a load in the vertical direction when drilling a rivet hole can be enhanced.