Composite Tube Assembly with Segmented Metallic End Fittings
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Solution Overview
Problem
Conventional composite tube assemblies with metallic end fittings hinder the reuse of these fittings when replacing composite tubes, as they are typically bonded and not easily detachable.
Innovation Solution
The method involves forming a composite tube with conical sections, disposing an end fitting around the second conical section, and coupling a locking ring to the end fitting using retention bolts, with an optional retaining ring to secure the locking ring, allowing for the use of a metallic insert co-molded with the tube for enhanced structural integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If metallic end fittings are bonded to composite tubes, then structural strength is improved, but reusability of fittings deteriorates
Solution Approach 1:
The end fitting is divided into multiple segments: a reusable metallic portion and a disposable composite tube portion with integrated metallic inserts. The metallic inserts are bonded to the composite tube, while the main metallic end fitting remains separate and can be reused. This segmentation allows the bonding function to be transferred to the disposable inserts rather than the reusable fittings.
Solution Approach 2:
The composite tube includes integrated metallic inserts that are bonded to the tube, serving as disposable bonding elements. When the composite tube needs replacement, these inserts remain with the old tube, allowing the expensive metallic end fittings to be removed and reused on new tubes. The disposable inserts absorb the bonding function that would otherwise require permanent attachment of valuable fittings.
2Reliability
If metallic end fittings are permanently bonded to composite tubes, then reliability of the assembly is improved, but adaptability for replacement deteriorates
Solution Approach 1:
The assembly is segmented into permanent bonded joints (metallic inserts to composite tube) and removable mechanical joints (locking rings and retaining rings). This allows the metallic end fittings to be reliably connected during operation but easily removed when replacement is needed, providing both reliability and adaptability.
Solution Approach 2:
The connection system transitions from a static permanent bond to a dynamic system where the connection state can change. The locking rings and retaining rings provide a mechanical connection that is secure during operation but can be quickly released, allowing the assembly to adapt between operational and replacement states.
3Ease of manufacture
If conventional bonding methods are used for end fittings, then manufacturing simplicity is maintained, but ease of disassembly deteriorates
Solution Approach 1:
The bonding function is segmented from the main metallic end fitting and transferred to integrated metallic inserts that are co-molded or bonded to the composite tube. This allows the end fitting itself to remain a separate, easily assembled component with simple mechanical connections, while the bonding function is handled by the disposable inserts.
Solution Approach 2:
The metallic inserts act as intermediaries between the composite tube and the metallic end fitting. These inserts provide the bonding interface with the composite tube while allowing the end fitting to connect through simple mechanical means (locking and retaining rings), eliminating the need for complex bonding of the end fitting itself.
Data Source
AI summary
Composite tube assemblies comprising a composite tube comprising a distal end having a first conical section and a second conical section, wherein a distal end of the first conical section is in contact with a proximal end of the second conical section having the same outer diameter as the distal end of the first conical section, wherein a proximal end of the first conical section and a distal end of the second conical section have a smaller outer diameter than the distal end of the first conical section, a locking ring disposed around the first conical section, an end fitting disposed around the second conical section, wherein the end fitting is coupled to the locking ring, and a retaining ring circumferentially disposed around the locking ring are disclosed.