Interlocking Tubular Joint for Dissimilar Materials
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Solution Overview
Problem
Existing methods for joining tubular materials, especially dissimilar materials, often result in increased outer diameter or decreased inner diameter at the joint, and may require welding of incompatible materials, leading to brittle compounds or inadequate bond strength.
Innovation Solution
The method involves cutting tubular materials with radial cuts to create interlocking pieces that are assembled without welding dissimilar materials together, using similar materials for welding only within each tube to maintain the original diameter and prevent deformation, thereby forming a strong and reliable joint.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If dissimilar materials are welded together, then a joint is formed, but brittle intermetallic compounds form making the weld brittle
Solution Approach 1:
The patent uses locking pieces made of materials compatible with each tube material as intermediaries. The first locking piece is made of a material compatible with the first tube, and the second locking piece is made of a material compatible with the second tube. These intermediary components enable joining dissimilar materials without direct welding between incompatible materials, thus avoiding brittle intermetallic compound formation while maintaining joint strength and reliability.
2Strength
If a lap joint is used to increase bonding surface area, then joint strength increases, but wall thickness at the joint increases
Solution Approach 1:
The patent segments the joint structure into separate locking pieces rather than using a traditional lap joint overlap. The locking pieces are discrete components that can be attached to the tubes without requiring substantial overlap areas. This segmentation allows the joint to achieve adequate bond strength through the locking mechanism and welding of similar materials, while avoiding the increased wall thickness that would result from a lap joint configuration.
3Strength
If press fit, shrink fit, or crimping is used to join tubes, then a joint is formed, but outer diameter increases or inner diameter decreases
Solution Approach 1:
The locking pieces serve as intermediary components that facilitate the joining process without requiring deformation of the tubes. By attaching the locking pieces to the tube ends and interlocking them, the joint is formed through mechanical engagement and welding of similar materials, rather than through press fit, shrink fit, or crimping operations that would alter the tube diameters. This preserves the original outer and inner diameters of both tubes at the joint.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach allows for the secure end-to-end connection of tubular materials without increasing the outer or decreasing the inner diameter, effectively joining dissimilar materials like stainless steel and nitinol without the need for welding them directly, resulting in a strong and reliable joint that resists various forces.
Implementation Method 1
By cutting the tubular materials with radial cuts using a tube cutting laser system or other method
Implementation Method 2
welding or attaching only similar materials to one another
Data Source
AI summary
An end-to-end tubular joint includes first locking pieces cut from the first tube and second locking pieces cut from the second tube, where the cuts have radial cut faces on the axially aligned cuts. The first and second locking pieces are interlocked with lateral extensions of the respective locking pieces bearing against one another and the radial cut surfaces distributed circumferentially around the joint so as to constrain relative movement between the parts. The first locking pieces are welded to the first tube and the second locking pieces are welded to the second tube to form a tube joint. An alternative forms cutouts in the first tube and fits locking pieces into the cutouts that are welded to a second member, such as a second tube or cylinder that fits into the first tube so as to form the tube joint.