Integral Composite Wing-Body Joint Pad-Up Area
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Solution Overview
Problem
Traditional mechanical butt joints used in aircraft construction are heavy, costly, and prone to fatigue, requiring numerous bolts and additional components that increase weight and operational costs.
Innovation Solution
The use of integral composite panels with interleaved plies of composite material to form a single, lightweight wing structure that integrates with a framework, reducing the need for mechanical fasteners by distributing loads through a built-up pad-up area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If traditional mechanical butt joints with numerous bolts are used, then bearing requirements are met, but weight increases and operational costs increase
Solution Approach 1:
The patent merges the wing panel and joint structure into a single integral composite component. The overlapping plies of composite material create a built-up pad-up area that is continuous and integrated, eliminating the need for separate mechanical joints, ribs, and bolts. This integration maintains bearing capability while significantly reducing weight by removing unnecessary mechanical fastening components.
Solution Approach 2:
The patent employs composite materials consisting of multiple overlapping plies arranged in an interwoven pattern. This composite construction creates a pad-up area with enhanced bearing capability that matches or exceeds traditional mechanical joints, while being lighter and more fatigue-resistant. The composite structure distributes loads effectively across the joint area without requiring numerous bolts.
2Strength
If traditional mechanical joints with multiple parts are used, then bearing requirements are met, but production time and manufacturing complexity increase
Solution Approach 1:
The patent combines multiple separate joint components (ribs, bolts, fasteners) into a single integral composite structure. The overlapping plies form a unified pad-up area that performs all the functions previously requiring separate parts, thereby reducing manufacturing complexity and production time while maintaining bearing capability.
Solution Approach 2:
The composite structure is segmented into multiple plies that are overlapped and interwoven to create the pad-up area. This segmentation at the material level allows for flexible design and manufacturing of the joint structure as a single integrated component, simplifying production compared to assembling multiple separate mechanical parts.
3Strength
If traditional bolted joints are used, then initial strength is achieved, but fatigue over time requires maintenance and replacement
Solution Approach 1:
The patent uses composite materials with overlapping plies that create a fatigue-resistant pad-up area. The composite construction distributes stresses more evenly across the joint, eliminating stress concentrations that occur at bolt holes and mechanical fasteners. This results in superior fatigue resistance and long-term reliability without requiring periodic maintenance or replacement.
Solution Approach 2:
The patent replaces the mechanical bolted joint system with a composite material-based pad-up area. This substitution eliminates the mechanical fasteners that are prone to fatigue failure, thereby improving long-term reliability and reducing maintenance requirements while maintaining initial joint strength.
Data Source
AI summary
Embodiments of integral composite panels and joints for composite structures are described In one implementation, an integrated panel spanning substantially the entire wingspan of an aircraft, includes at least a center portion and a pair of outwardly projecting wing portions. The portions may include a skin formed from successive layers or plies of composite material which overlap and offset at the joint between respective sections creating a pad-up area to carry loads between the portions. In a particular implementation, the skin is laid over one or more structural stringers which are transitioned into the joints between sections such as by tapering of the thickness and/or stiffness of the stringer.