Cryogenic Separation of Adhesive Lap Joints in Airfoil Sheaths
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Solution Overview
Problem
Mechanical separation of adhesively bonded components, such as sheaths and airfoils, often results in significant damage, making them unusable, and existing methods are destructive and inefficient.
Innovation Solution
A method involving the use of a cryogenic fluid stream, focused at an angle less than 45 degrees, preferably using liquid nitrogen, to nondestructively separate adhesive lap joints by reducing the adhesive's resilience and thermal expansion mismatch, allowing for the preservation of at least one component for reuse.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If mechanical separation methods are used to separate adhesively bonded components, then the separation can be achieved, but significant damage occurs to the components making them unusable
Solution Approach 1:
The patent replaces mechanical separation methods with a thermal field-based method using cryogenic fluid streams. Instead of applying mechanical forces that cause damage, the system uses focused cold streams to selectively reduce adhesive strength through thermal effects, allowing separation while preserving component integrity
Solution Approach 2:
The patent changes the temperature parameter of the adhesive joint by applying cryogenic fluids (liquid nitrogen or carbon dioxide) to selectively reduce the adhesive's strength. This parameter change allows the adhesive to fail in a controlled manner while the bonded components remain intact and reusable
2Productivity
If conventional separation methods are used, then components can be separated, but extensive damage requires extensive restoration or renders parts unusable
Solution Approach 1:
The patent replaces destructive mechanical separation with a thermal process using cryogenic fluid streams. This substitution eliminates the need for extensive restoration by preserving component integrity, thereby improving productivity while reducing manufacturing complexity for repairs
Solution Approach 2:
The patent utilizes phase transitions of cryogenic fluids (liquid nitrogen or carbon dioxide) to achieve separation. The rapid phase change from liquid to gas creates controlled thermal effects that weaken the adhesive bond without damaging the components, enabling efficient separation with minimal restoration needs
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 method effectively separates adhesively bonded components with minimal damage, enabling the reuse of airfoil bodies by reducing the adhesive's strength and exploiting thermal expansion differences, thus facilitating the separation of sheaths from airfoils without causing extensive damage.
Implementation Method 1
emitting a cryogenic fluid stream from the fluid emitter at the adhesive lap joint by focusing the cryogenic fluid stream at the adhesive lap joint
Implementation Method 2
reducing the adhesive's resilience and thermal expansion mismatch
Implementation Method 3
The cryogenic fluid stream comprises liquid nitrogen
Implementation Method 4
reducing the adhesive's resilience and thermal expansion mismatch, allowing for the preservation of at least one component for reuse
Data Source
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AI summary
A method of separating a lap joint assembly (100; 400) may include positioning a fluid emitter (450) relative to a lap joint assembly (400). The lap joint assembly (400) may include an adhesive lap joint (403) between a first component (401) and a second component (402). The method may further include emitting a cryogenic fluid stream (451) from the fluid emitter (450) at the adhesive lap joint (403). Positioning the fluid emitter (450) and emitting the cryogenic fluid stream (451) may include orienting the fluid emitter (450) such that an angle between the cryogenic fluid stream (451) and the adhesive lap joint (403) is less than 45 degrees. The first component (401) may be a sheath (120) and the second component (402) may be an airfoil body (110).