Composite Tubular Strut With Internal Stiffeners for Faster Fabrication
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing fabrication methods for composite tubular struts are labor-intensive and time-consuming, requiring precise hand layup and multiple autoclave cure cycles, and they do not adequately optimize the strength-to-weight ratio.
Innovation Solution
A tubular composite strut design that incorporates internal stiffeners co-cured with the tube body, using an internal mandrel for layup and automatic fiber placement, which reduces the need for an autoclave cure cycle and allows for a tailored cross-sectional configuration to maximize strength-to-weight ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If double step joints are used to attach end fittings to tubular composite bodies, then attachment strength is improved, but fabrication complexity and time increase due to requiring two autoclave cure cycles and precise hand layup
Solution Approach 1:
The patent combines the attachment of end fittings to the tubular composite body with the attachment of internal stiffeners to the same body into a single simultaneous bonding operation. This merging of operations eliminates the need for separate cure cycles, reducing fabrication complexity while maintaining the strength benefits of bonded attachments.
2Strength
If double step joints are used to attach end fittings, then attachment strength is improved, but manufacturing time increases due to requiring two autoclave cure cycles
Solution Approach 1:
The patent merges multiple bonding operations into a single simultaneous process where end fittings and internal stiffeners are attached to the tubular composite body in one autoclave cure cycle. This eliminates the sequential two-cycle process, significantly reducing manufacturing time while preserving the strength advantages of bonded joints.
3Strength
If relatively thick wall is used in tubular composite bodies, then design load criteria are met, but strength-to-weight ratio deteriorates
Solution Approach 1:
The patent applies local quality by positioning internal stiffeners at specific locations within the tubular composite body where bending stresses are highest. This localized reinforcement allows the tube wall thickness to be reduced in non-critical areas, optimizing the strength-to-weight ratio by providing strength exactly where needed rather than uniformly throughout the structure.
Solution Approach 2:
The patent employs composite materials strategy by combining the tubular composite body with internal composite stiffeners bonded together. This creates a composite-of-composites structure where the combined system achieves superior strength-to-weight ratio compared to a single thick-walled tube, as the internal stiffeners provide additional load-bearing capacity without proportionally increasing weight.
4Manufacturing precision
If precise hand layup is used for fabricating composite struts, then manufacturing precision is improved, but productivity decreases due to labor intensity
Solution Approach 1:
The patent implements self-service by designing the tubular composite body with an internal mandrel that automatically maintains the correct geometric configuration and positioning of internal stiffeners during the bonding process. The mandrel structure itself provides the precision alignment that would otherwise require skilled hand layup, enabling less skilled workers to achieve consistent precision results.
Data Source
AI summary
A system and method for forming a strut. A strut comprises a laminated composite tube having a substantially hollow interior and a pair of longitudinal stiffeners attached to opposite sides of the laminated composite tube.