Shape Memory Alloy Adhesive for Non-Destructive Composite Disassembly
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Solution Overview
Problem
Existing methods for removing a metal part adhesively bonded to a composite material part, such as in aeroengine components, often damage the composite material by tearing fibers, dissolving the matrix, or deforming the structure.
Innovation Solution
Using an adhesive filled with shape memory alloy elements, such as Ni—Ti or Cu—Al—Be, which undergoes a martensitic transformation to contract or expand, creating pores or cracks in the adhesive interface when subjected to heat treatment, allowing for non-destructive separation of the parts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If traditional methods (tearing, chemical dissolving, or heating) are used to remove a metal part from composite material, then the bonding can be broken, but the composite material is damaged (fibers torn, matrix dissolved, or shape deformed)
Solution Approach 1:
The adhesive contains shape memory alloy filler elements that undergo martensitic transformation when subjected to heat treatment. This phase transition causes the filler elements to contract or expand, creating pores or cracks in the adhesive interface that weaken the bonding, allowing non-destructive removal of the metal part without damaging the composite material structure
Solution Approach 2:
The invention changes the physical and chemical parameters of the adhesive by incorporating shape memory alloy elements with specific martensitic transformation temperatures. When heat treatment is applied, the temperature parameter triggers the phase transition in the filler elements, which alters the adhesive's mechanical properties and creates weaknesses in the bonding interface for controlled separation
2Ease of operation
If the adhesive joint is heated to weaken the bonding, then the parts can be separated, but the composite material may be deformed
Solution Approach 1:
The shape memory alloy filler elements undergo martensitic transformation at specific temperatures, causing them to contract or expand and create pores or cracks in the adhesive interface. This phase transition mechanism allows the bonding to be weakened through controlled heat treatment without deforming the composite structure, as the damage is localized to the adhesive rather than the composite material itself
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
Enables the safe removal of metal parts from composite materials without damaging the composite structure by weakening the adhesive interface through thermal expansion or contraction, facilitating easy disassembly without structural damage.
Implementation Method 1
subjecting the assembly to heat treatment that goes past the martensitic transformation temperature of the alloy and thus causes the filler elements to contract or to expand
Implementation Method 2
subjecting the assembly to heat treatment that goes past the martensitic transformation temperature of the alloy and thus causes the filler elements to contract or to expand
Data Source
AI summary
A method of bonding a first part on a second part made of composite material by an adhesive, in which the adhesive is filled with elements of shape memory alloy, is provided. A method of un-sticking the first part adhesively bonded on the composite material second part is also provided. The un-sticking method includes a step of weakening the adhesive interface that consists in subjecting the adhesively bonded parts to heat treatment performed at a temperature that is lower or higher than the martensitic transformation temperature of the shape memory alloy elements.