Multi-phase adhesive crack arrestment
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Solution Overview
Problem
In aerospace and automotive applications, existing adhesive solutions require certification methods that often necessitate the use of mechanical fasteners for crack arrestment, which complicates the bonding process and may not ensure airworthiness due to regulatory requirements.
Innovation Solution
Development of multi-phase structural film adhesive systems that integrate crack arrestment within the adhesive itself, combining adhesives with distinct properties to provide a broader temperature range of operation and improved fracture toughness, allowing for the potential reduction or elimination of mechanical fasteners.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If mechanical fasteners are used for crack arrestment in adhesive bonds, then reliability of the bond is improved, but device complexity increases
Solution Approach 1:
The patent extracts the crack arrestment function from mechanical fasteners and transfers it to the adhesive material itself. The adhesive contains discontinuous phases or inclusions that act as crack arrestment features, eliminating the need for separate mechanical fasteners while maintaining bond reliability.
Solution Approach 2:
The patent merges multiple functions into the adhesive material: bonding, crack propagation resistance, and crack arrestment. By incorporating discontinuous phases within the adhesive, the system combines the matrix material's bonding capability with the dispersed phases' crack arrestment function, simplifying the overall bonding system.
2Reliability
If high fracture toughness adhesive is used to retard crack propagation, then reliability is improved, but the adhesive cannot achieve high modulus to resist crack initiation
Solution Approach 1:
The patent applies local quality by creating regions with different properties within the adhesive. The matrix provides high fracture toughness for crack propagation resistance, while the discontinuous phases provide high modulus for crack initiation resistance. Each phase performs its function locally, and the combination achieves both properties globally.
Solution Approach 2:
The patent uses composite material structure where a matrix adhesive with high fracture toughness contains discontinuous phases with high modulus. This composite structure allows the material to exhibit both crack propagation resistance (from the matrix) and crack initiation resistance (from the dispersed phases), resolving the property trade-off.
3Duration of action of stationary object
If adhesive solutions with high fracture toughness are used, then crack propagation is retarded, but crack initiation resistance is reduced
Solution Approach 1:
The patent employs composite material structure where the matrix provides high fracture toughness for extended crack propagation resistance, while the embedded discontinuous phases provide high modulus for crack initiation resistance. This composite approach allows simultaneous achievement of both properties that are typically mutually exclusive in homogeneous adhesives.
Data Source
AI summary
Provided are adhesive articles and related methods of making and use. The adhesive article includes one or more patterned adhesive layers comprising compositionally and spatially distinct adhesives that are laterally disposed relative to each other. The first and second adhesives are optionally capable of being functionally cured to provide a structural adhesive bond with a substrate. These adhesives can provide high fracture toughness and high modulus characteristics not otherwise possible in a homogeneous adhesive composition. These adhesives can provide some degree of crack arrestment and significantly reduce the need for mechanical fasteners in industrial bonding applications.