Composite Wing Leading Edge Monocoque Structure
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Solution Overview
Problem
The 'black aluminium' design for composite aircraft wings limits the potential performance benefits of composite materials due to features like sharp corners and fasteners that reduce local strength, requiring reinforcement, which adds cost and weight.
Innovation Solution
A wing structure is developed with a skin that forms a monocoque beam, eliminating features that weaken the composite material, and using duct stringers and structural foam to provide structural reinforcement, allowing the skin to carry primary loads and eliminate the need for spars and bolted joints.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a segmented box structure with spars, ribs and stiffened skin panels is used, then structural strength is improved, but weight increases due to numerous fasteners and local reinforcements required
Solution Approach 1:
The patent merges the functions of spars, ribs, and skin panels into an integrated monolithic composite structure. The skin itself is designed to carry primary loads without requiring separate spar components, eliminating numerous fasteners and local reinforcements while maintaining structural strength.
Solution Approach 2:
The invention extracts and eliminates the spar components from the traditional segmented box structure. By designing the skin to carry primary loads directly, the patent removes the need for internal spars and their associated fasteners, reducing weight while preserving structural integrity.
2Strength
If fasteners are used to attach leading edge structure to spars, then structural integrity is maintained, but the composite material strength is reduced due to bolt holes and local weakenings
Solution Approach 1:
The patent merges the leading edge structure with the skin through integral construction, eliminating the need for separate attachment components. This integration removes bolt holes and local weakenings while maintaining structural integrity through the continuous composite material.
Solution Approach 2:
The invention extracts and eliminates fasteners and their associated attachment holes from the leading edge structure. By designing the leading edge as an integral part of the skin, the patent removes the sources of local strength reduction while preserving structural connectivity.
3Strength
If sharp corners and fastener holes are provided in the composite structure, then structural assembly is enabled, but strain allowables are limited due to local stress concentrations
Solution Approach 1:
The patent employs curved transitions and rounded corners throughout the composite structure, eliminating sharp corners that create stress concentrations. The leading edge and other geometric features are designed with continuous curvature to distribute stresses evenly, improving strain allowables while maintaining manufacturability.
4Weight of moving object
If a monocoque beam structure with skin carrying primary loads is used, then weight is reduced by eliminating spars and fasteners, but manufacturing complexity increases
Solution Approach 1:
The patent segments the manufacturing process into manageable stages, such as forming the skin structure first and then integrating leading edge and control surface components. This segmentation of the manufacturing process reduces complexity while enabling the weight benefits of the monocoque design.
Data Source
AI summary
A section of an aircraft wing including a leading edge of the aircraft wing. A leading edge part of the section includes ribs; and a skin fixedly attached to the ribs to form a spanwise series of adjacent cells. Each cell includes an enclosed volume bounded by the skin at the leading edge and a pair of the ribs. At least one cell of the series of adjacent cells is a dry cell include a mounting point for mounting a leading edge high-lift device support apparatus in the dry cell. The skin at the leading edge provides a primary load path for carrying at least some of a spanwise primary load experienced by the section when in use on an aircraft.