Interference-Fit Sleeve Coupling for Compact Rebar Joints
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Solution Overview
Problem
Existing coupling devices face challenges in efficiently joining elongated elements while meeting requirements of strength, stiffness, ductility, and dimensional constraints, particularly in applications like reinforced concrete, where they must not protrude beyond the reinforcing bar cage and interfere with transverse bars, and withstand various stress conditions including axial stress and Poisson's effect.
Innovation Solution
A coupling device comprising a sleeve with deformation means that causes local deformation between the sleeve and elongated elements, using high-energy impulse insertion to create an interference fit, allowing for strong and ductile coupling that simulates the stress-strain relationship of uncoupled elements, and includes features like grooves and orifices to guide the deformation means for optimal alignment and interaction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If the coupling device is designed to meet dimensional requirements (not protruding beyond transverse steel), then the coupling device fits within the reinforcing bar cage without interfering with transverse bars, but the coupling device length is constrained and may limit coupling strength or require special transverse bar sets
Solution Approach 1:
The coupling device is divided into multiple segments or sections along its length, with deformation means distributed at different positions. This segmentation allows the device to achieve the required coupling strength through cumulative deformation effects while keeping each individual segment compact enough to fit within the transverse bar spacing constraints
Solution Approach 2:
The coupling device concentrates deformation means at specific local positions rather than distributing them uniformly. This local quality approach creates high-strength coupling zones where needed while maintaining overall compact dimensions, allowing the device to achieve sufficient coupling strength without increasing its overall length beyond transverse bar spacing
2Strength
If the coupling device length is increased to provide adequate coupling strength, then the coupling strength improves, but the coupling device may interfere with transverse bar placement or require reduction in longitudinal bar spacing
Solution Approach 1:
The coupling device is divided into multiple segments or sections along its length, with deformation means distributed at different positions. This segmentation allows the device to achieve the required coupling strength through cumulative deformation effects while keeping each individual segment compact enough to fit within the transverse bar spacing constraints
Solution Approach 2:
The coupling device incorporates deformation means that can be activated or engaged dynamically during the coupling process. This allows the device to maintain a compact form during installation (facilitating transverse bar placement) while developing full coupling strength through controlled deformation of the joined elements
3Strength
If deformation means are inserted with high-energy impulse to create interference fit, then the coupling strength and ductility improve, but the insertion process requires precise control to avoid damage
Solution Approach 1:
The coupling device includes pre-formed deformation means or pre-configured interference fit features that are prepared in advance during manufacturing. This preliminary action ensures that the high-energy impulse insertion process simply activates pre-designed coupling mechanisms rather than requiring precise control of complex deformation processes during installation
Solution Approach 2:
The deformation means are designed to self-regulate during high-energy impulse insertion, where the interference fit itself provides feedback control. The deformation means engage and deform the joined elements in a controlled manner through the impulse force, with the material properties and geometric constraints automatically limiting the deformation to safe levels without requiring external control systems
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
The device provides a strong, ductile, and efficient coupling that maintains the stress-strain properties of uncoupled elements, resisting various stresses and strains, including Poisson's effect, while minimizing interference and ensuring adequate cover concrete thickness, thus enhancing structural efficiency and durability.
Implementation Method 1
at least one deformation means fitted with interference between, and causing local deformation about, at least part of the inner surface of the sleeve and/or an adjacent outer surface of the at least one elongated element
Implementation Method 2
causing local deformation about, at least part of the inner surface of the sleeve and/or an adjacent outer surface of the at least one elongated element
Data Source
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AI summary
Described herein is a coupling device, associated parts and a method of use thereof. In one aspect, a coupling device is described comprising a sleeve with an inner surface that encloses at least part of at least one elongated element to be coupled; and at least one deformation means fitted with interference between, and causing local deformation about, at least part of the inner surface of the sleeve and/or an adjacent outer surface of the at least one elongated element. A deformation means insertion tool, a coupling sleeve, a deformation means, and a method of coupling at least one element are also described. The described coupling device, associated parts and a method of use offer the ability to couple together different elements in a strong and/or ductile manner, coupling being tuneable as needed to suit the preferred application. The coupling described may overcome art issues associated with bulky size of coupling, in particular, radial protrusion. The coupling may also increase the coupling force therefore increase the load that may be managed across the coupling device. Further, the way the parts are assembled may minimise generation of localised points of stress therefore also increasing the load that may be managed across the coupling device.