Composite Beam Joint Locking Structure for Reliable Load Transfer
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Solution Overview
Problem
Reliably transferring complex loads such as axial, torsional, and bending loads at composite beam joints, particularly where composite beams are joined with metal end pieces, is a challenge due to the high tensile properties of composite materials, which can lead to stress and strain issues.
Innovation Solution
The use of wedge-shaped inner and outer locking features, where the end piece and composite tube are formed of different materials, with the end piece having wedge-shaped inner locking features configured as isosceles triangles and the end cap featuring wedge-shaped outer locking features connected by a collar, helps to distribute and react these loads effectively, minimizing mutual movement and stress between the composite tube and end piece.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If composite beams are joined with metal end pieces to utilize high tensile properties, then strength is improved, but stress and strain issues occur at beam joints leading to unreliable load transfer
Solution Approach 1:
The patent applies local quality by creating wedge-shaped imprints and depression surfaces at specific locations on the composite tube where it joins the metal end piece. These localized structural modifications concentrate load transfer paths and distribute stresses uniformly at the critical joint interface, preventing stress concentration while maintaining the high tensile properties of the composite beam.
Solution Approach 2:
The patent utilizes composite materials by forming the beam tube from composite material with high tensile properties while joining it to metal end pieces. The wedge-shaped imprints and depression surfaces create a hybrid interface that effectively transfers complex loads (axial, torsional, and bending) between the composite and metal components, resolving the reliability issue at material junctions.
2Reliability
If wedge-shaped locking features are used to distribute loads, then load transfer reliability is improved, but manufacturing complexity increases
Solution Approach 1:
The patent applies preliminary action by forming the wedge-shaped imprints and depression surfaces during the composite tube manufacturing process itself, before the actual assembly with the end piece. This integrated forming approach creates the load-distributing locking features as part of the tube fabrication, avoiding additional post-assembly operations and reducing overall manufacturing complexity despite the sophisticated joint geometry.
Data Source
Figure 1A~1B
Figure 2~3
Figure 4
AI summary
Disclosed is a composite beam structure having: an end piece (110), an end piece outer periphery surface, and an end piece mating end (140) defining an end piece axial boundary, the end piece includes wedge-shaped inner locking features (180) 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 (190) 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 (230) 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.