Multispar Lifting Surface Corner Reinforcement
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In multispar torsion box structures, transferring axial loads without additional internal structures is challenging due to the closed cell configuration, which limits access and requires reinforcement, increasing weight, cost, and assembly complexity.
Innovation Solution
The multispar lifting surface incorporates corner reinforcements with increased thickness in the open and closed cells, and an axial rod fitting with a L-shaped cross-section that directly engages the rear spar and surfaces, allowing load transfer without internal fittings, using a longitudinal profile and lug for secure attachment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If additional internal structures (counter fittings) are installed inside the torsion box to transfer axial loads, then load transfer capability is improved, but device complexity and assembly operations increase
Solution Approach 1:
The patent extracts the load transfer function from the interior of the closed cells and relocates it to the exterior corner reinforcements. By removing the need for internal counter fittings and placing reinforcement elements at the accessible corner regions, the solution eliminates internal structural complexity while maintaining load transfer capability through the axial rod fitting and reinforced corners.
Solution Approach 2:
The axial rod fitting acts as an intermediary element that bridges the movable control surface to the reinforced corners of the torsion box. This fitting distributes axial loads from the hinge arms through the axial rod to the corner reinforcements, eliminating the need for direct internal counter fittings while maintaining structural integrity.
2Strength
If additional internal structures are installed to transfer axial loads, then load transfer capability is improved, but assembly operations and cost increase
Solution Approach 1:
The patent removes the complex internal assembly operations required for installing counter fittings inside closed cells. By relocating the load transfer function to exterior corner reinforcements that can be accessed and installed from the outside, the assembly process is simplified and cost-reduced while maintaining load transfer capability.
3Strength
If cutting is made in the closed cell structure to access interior for reinforcement, then load transfer capability is improved, but structural integrity deteriorates and assembly complexity increases
Solution Approach 1:
The patent extracts the reinforcement function from the interior of closed cells to the exterior corner regions. By placing reinforcement elements at accessible corner locations rather than attempting to reinforce internal cell structures, the solution avoids cutting into closed cells, thereby preserving structural integrity and eliminating the need for complex internal access operations.
4Strength
If corner reinforcements with increased thickness are used, then load transfer capability is improved, but weight increases
Solution Approach 1:
The patent applies local quality by concentrating reinforcement only at the specific corner regions where axial loads are transferred, rather than uniformly thickening the entire torsion box structure. The corner reinforcements are strategically positioned at the intersection points where the axial rod connects to the spar and surface, providing localized strength enhancement with minimal weight increase.
Data Source
Figure 1
Figure 2
Figure 3A
AI summary
A multispar lifting surface (30) comprising a multispar torsion box (32) having corner reinforcements (25), a movable control surface, and an axial rod fitting (40). The movable control surface comprises a movable element (1), a hinged connection (6.1) joined to the movable element (1), and an axial rod (7) joining the hinged connection (6.1) to the rear spar (5) of the multispar torsion box (32).The axial rod fitting (40) is configured to join the axial rod (7) and the multispar torsion box (32); and comprises a longitudinal profile (10) resting against the rear spar (5), and a lug (20) joined to the longitudinal profile (10) at one end and to the axial rod (7) at another end; the lug (20) defining a plane comprising the longitudinal axis of the axial rod (7). This multispar lifting surface (30) is able to support sideward forces without any additional structure.