Composite Beam Joint Wedge Locking for Complex Load Transfer
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Solution Overview
Problem
Reliably transferring complex loads such as axial, torsional, and bending loads at the beam joints of composite beams, particularly when joined with metal end pieces, is challenging due to the high tensile properties of composite materials.
Innovation Solution
A composite beam joint design featuring wedge-shaped inner and outer locking features is implemented, where the end piece has wedge-shaped inner locking features that project outward and are covered by corresponding wedge-shaped imprints in the composite tube, and an end cap with wedge-shaped outer locking features is secured to the composite tube, effectively distributing and reacting these loads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If composite materials are used for beams to utilize high tensile properties, then weight is reduced and strength is improved, but reliably transferring complex loads at beam joints becomes challenging
Solution Approach 1:
The locking mechanism is divided into multiple wedge-shaped locking features (both inner and outer) distributed around the beam joint, with each feature independently contributing to load transfer. This segmentation allows complex loads to be distributed across multiple discrete load paths, improving reliability while maintaining the high strength of composite materials.
Solution Approach 2:
The locking features utilize asymmetric wedge shapes with specific angles and orientations that are optimized for transferring complex loads. The wedge geometry creates mechanical interlocking that is asymmetric in nature, with different load transfer characteristics for different loading directions, enabling reliable transfer of axial, torsional, and bending loads simultaneously.
2Reliability
If wedge-shaped locking features are implemented to transfer complex loads, then load transfer capability is improved, but device complexity increases
Solution Approach 1:
The inner and outer locking features are merged into a unified wedge-shaped geometry that performs multiple functions simultaneously. The same wedge structure provides both the locking action and the load transfer mechanism, eliminating the need for separate locking and load-bearing components, thus reducing overall device complexity while maintaining high load transfer capability.
Solution Approach 2:
The inner locking features are nested within the composite beam structure, while outer locking features are nested on the exterior. This nested arrangement allows the locking mechanism to be integrated within the existing beam geometry rather than adding external attachments, minimizing the increase in device complexity.
3Reliability
If composite tube is clamped against end piece to form wedge-shaped imprints, then load distribution is optimized, but manufacturing precision requirements increase
Solution Approach 1:
The wedge-shaped locking features are pre-formed on the end piece before the composite tube is applied. This preliminary action ensures that the imprints are formed with consistent geometry and orientation, reducing the precision requirements during the final assembly and curing process. The pre-formed wedges guide the composite material into the correct position and shape.
Solution Approach 2:
The manufacturing process utilizes changes in material parameters during curing - the composite tube material transitions from a moldable state to a cured state, allowing the wedge-shaped imprints to be formed with acceptable precision during the molding process and then locked in place upon curing, reducing the need for extremely tight tolerances.
Data Source
AI summary
Disclosed is a composite beam structure having: an end piece, an end piece outer periphery surface, and an end piece mating end defining an end piece axial boundary, the end piece includes wedge-shaped inner locking features that are formed to project outwardly from the end piece outer periphery surface at the end piece mating end and are spaced apart from one another in the hoop direction; and a composite tube configured to surround at least a portion of the end piece mating end to form a beam joint, wedge-shaped imprints are formed through the composite tube, corresponding to the wedge-shaped inner locking features, the wedge-shaped imprints define respective composite tube wedge-shaped depression surfaces about a composite tube inner periphery and composite tube wedge-shaped boss surfaces about a composite tube outer periphery, and the wedge-shaped inner locking features of the end piece are covered by the composite tube wedge-shaped depression surfaces.