Bolted-Bonded Joint with Shear Transfer Layer
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Solution Overview
Problem
Existing structural assemblies face challenges in efficiently and uniformly transferring loads, particularly shear loads, across joints, leading to localized stresses and potential failure, and conventional manufacturing methods for fastener holes are time-consuming and costly.
Innovation Solution
A lightweight bolted-bonded structural attachment system that includes a shear load transfer structure separate from the joining mechanism, with a compression preload feature, allowing for flexible assembly and accommodating in-plane and angular mismatches, using mechanical fasteners and compliant adhesives or shear transfer layers to distribute loads effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional manufacturing methods are used to drill fastener holes during detail fabrication stage, then holes can be created early in manufacturing process, but holes become angularly and/or linearly mismatched during assembly requiring expensive match-drilling
Solution Approach 1:
The patent divides the hole formation process into two independent stages: (1) drilling holes during detail fabrication with standard tolerances, and (2) accommodating misalignment during final assembly using compliant members. This segmentation eliminates the need for expensive match-drilling while maintaining assembly precision.
Solution Approach 2:
The patent changes the tolerance parameters for hole drilling during fabrication, allowing larger angular and linear deviations. The compliant members then compensate for these parameter variations during assembly, enabling faster manufacturing without sacrificing final alignment.
2Strength
If loads are transferred through adhesively bonded joints only, then lightweight structure is achieved, but concentrated stresses cause bond failure and unreliable load transfer
Solution Approach 1:
The patent creates a hybrid bolted-bonded joint system that combines mechanical fasteners with adhesive bonds. The fasteners provide reliable load transfer through bearing and shear, while the adhesive provides distributed stress transfer and sealing. This composite approach eliminates the reliability issues of pure adhesive joints while maintaining lightweight characteristics.
Solution Approach 2:
The patent merges two joining methods (mechanical fastening and adhesive bonding) into a single integrated joint system. The fasteners and adhesive work together to transfer loads, with the compliant members ensuring uniform stress distribution between the two mechanisms, thereby achieving both strength and reliability.
3Manufacturing precision
If match-drilling is performed during assembly stage, then precise hole alignment is achieved, but additional tooling and substantial time are required unfavorably impacting manufacturing flow and cost
Solution Approach 1:
The patent extracts the precision alignment requirement from the hole drilling process itself and relocates it to the compliant member design. Instead of requiring precise drilling, the system allows standard drilling and uses the compliant members to absorb misalignment, eliminating the need for complex match-drilling tooling.
Solution Approach 2:
The compliant members act as sacrificial elements that accommodate hole misalignment through their elastic deformation. These relatively simple, low-cost components replace expensive match-drilling tooling and substantial assembly time, providing a more economical solution for achieving precise fastener alignment.
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 solution provides enhanced strength, reliability, and reduced assembly time and costs by allowing for consistent joint performance with reduced manufacturing expenses and improved static and fatigue performance compared to conventional bolted or bonded joints.
Implementation Method 1
means for providing a compression preload to the means for transferring shear loads between the first member and the second member
Implementation Method 2
The fastener includes a pin, a head on the pin, and a nut threadably engaged on the pin
Implementation Method 3
The adhesive layer transfers shear loads between the first member and the second member
Data Source
AI summary
An apparatus for joining a first member and a second member includes fasteners for joining the first member and the second member, a shear transfer layer for transferring shear loads between the first member and the second member separate from the fasteners for joining the first member and the second member. An assembly includes a first member, a second member, and fasteners for joining the first member and the second member. The assembly further includes a shear transfer layer for transferring shear loads between the first member and the second member separate from the fasteners for joining the first member and the second.