Double Shear Bonded Joint for Tubular Structures
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Solution Overview
Problem
Traditional bonded joints for tubular structures, such as those using lap joints or mechanical fasteners, face issues like poor bonding, stress distribution, and increased manufacturing complexity, particularly when using materials like carbon fiber, which are difficult to drill or cut without weakening.
Innovation Solution
A bonded joint design featuring a hollow member with a receiving channel of complementary shape, where the hollow member is secured within the channel by a bonding agent, creating a double shear joint that maintains stress in shear without bending forces, and allows for improved bonding and simplified assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a lap joint is used for bonding tubular components, then the joint can be assembled by sliding components together, but the bonding quality deteriorates due to wiping action removing adhesive and creating air gaps
Solution Approach 1:
The joint is divided into two separate bonding surfaces: the end fitting has a first bonding surface and the tubular component has a second bonding surface. This segmentation allows each surface to be optimized for its specific bonding function, with the adhesive applied to the end fitting's bonding surface that contacts the tubular component's bonding surface, preventing the wiping action that occurs in traditional lap joints
Solution Approach 2:
The invention transitions from a traditional lap joint configuration to a perpendicular bonding arrangement where the adhesive bonds the end fitting to the tubular component at right angles. This dimensional change eliminates the sliding wiping action while maintaining assembly simplicity, as the tubular component is inserted perpendicular to the end fitting's bonding surface
2Ease of operation
If a lap joint is used for bonding tubular components, then the joint can be assembled by sliding components together, but the stress distribution worsens due to single shear creating offset forces and torque
Solution Approach 1:
The bonding interface is segmented into distinct perpendicular surfaces, creating a double shear joint configuration. This segmentation allows the load to be distributed across two separate bonding planes rather than a single lap joint interface, eliminating the offset forces and torque that cause stress concentration in traditional lap joints
Solution Approach 2:
The invention changes the joint configuration from a single-plane lap joint to a perpendicular double shear joint. By orienting the bonding surfaces at right angles to each other, the joint experiences loads in two dimensions simultaneously, distributing stress more evenly and preventing the bending and twisting moments that occur in single shear lap joints
3Strength
If mechanical fasteners are added to tubular structures, then joint strength improves, but manufacturing complexity increases due to additional drilling or cutting steps
Solution Approach 1:
The invention replaces the mechanical fastening system with a chemical bonding system using adhesive. Instead of requiring drilling, cutting, or other mechanical operations to install fasteners, the adhesive is applied to the end fitting's bonding surface and bonds the tubular component in place, eliminating all mechanical fastening steps while maintaining joint strength
Solution Approach 2:
The invention changes the bonding mechanism from mechanical (fasteners) to chemical (adhesive). This parameter change in the bonding method eliminates the need for mechanical operations like drilling or cutting, significantly reducing manufacturing complexity while providing sufficient joint strength through the chemical bond between the adhesive and the tubular component
4Strength
If mechanical fasteners are added to tubular structures, then joint strength improves, but the material integrity worsens due to wear, stress points, and fiber interruption
Solution Approach 1:
The invention replaces mechanical fasteners with a chemical adhesive bond, eliminating the physical contact points that cause wear and stress concentrations. The adhesive distributes loads uniformly across the bonding surface without creating localized stress points or interrupting continuous fibers in composite tubular components, thereby preserving material integrity while maintaining joint strength
Data Source
AI summary
Channel joints (1) can permit bonding a tube or tubular member (30) to an end fitting (20) in double shear. The channel joint may include a receiving channel (25) in the end fitting (20) that is complementary in shape to the tube, tubular member, or other hollow member (30) that is to be fitted and bonded with the end fitting. The use of a channel joint allows for simplified assembly because the receiving channel acts as a reservoir for the bonding agent or adhesive (50). Upon insertion of the tube, tubular member, or other hollow member into the adhesive-loaded receiving channel, the adhesive will backflow to fill the voids in the joint and expel the excess adhesive.