Pourable Structural Foam Splicing Honeycomb Cores
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Solution Overview
Problem
Conventional methods for repairing and splicing honeycomb core stiffened structures are expensive, time-consuming, and inadequate, particularly when dealing with non-compatible materials, and require multiple adhesive cure cycles, which can lead to instability during autoclave curing.
Innovation Solution
The use of pourable structural foam to repair, splice, and join honeycomb core structures by filling cavities and expanding to provide a stable bonding surface, allowing for room temperature curing without the need for specialized tooling or thermal equipment, and enabling machining at severe angles and complex contours.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional adhesive bonding methods are used to splice honeycomb core members, then bonding between cell walls is achieved, but the process becomes expensive, time-consuming, and requires multiple adhesive cure cycles
Solution Approach 1:
The invention changes the bonding mechanism from adhesive-based to foam-based, utilizing the expansion and curing properties of pourable foam to create strong bonds between honeycomb core members and adjacent structures without requiring multiple adhesive cure cycles
Solution Approach 2:
The invention utilizes the phase transition of pourable foam from liquid to solid state through expansion and curing, allowing the foam to fill cavities and bond surfaces together in a single operation, eliminating the need for multiple adhesive application and curing cycles
2Strength
If conventional adhesive bonding methods are used to join honeycomb core to adjacent structure, then bonding is achieved, but the process becomes expensive, time-consuming, and requires adhesive cure cycles
Solution Approach 1:
The invention changes the bonding approach from traditional adhesive application to pourable foam injection, where the foam expands to fill cavities and bond the honeycomb core to adjacent structures, simplifying the manufacturing process and eliminating cure cycle requirements
Solution Approach 2:
The pourable foam acts as an intermediary material that fills the interface between the honeycomb core and adjacent structure, creating a bonding medium that eliminates the need for separate adhesive application and curing processes
3Reliability
If low bevel angle is used on honeycomb core to prevent crushing during autoclave pressure, then structural integrity is maintained, but manufacturing becomes labor intensive with multiple cure cycles and weight penalties
Solution Approach 1:
The invention changes the bevel angle parameter from conventional low angles to severe angles, enabled by the use of pourable foam that provides support during machining and curing, allowing faster machining speeds and improved manufacturing efficiency without compromising core stability
Solution Approach 2:
The pourable foam is applied to the honeycomb core before machining operations, providing preliminary support and stabilization that enables severe bevel angles to be machined without damaging the core structure, thereby improving manufacturing efficiency
4Productivity
If severe bevel angles and complex contours are machined on honeycomb core, then manufacturing efficiency is improved, but the unstable honeycomb core becomes difficult to machine at conventional feed rates
Solution Approach 1:
The pourable foam is applied to the honeycomb core before machining operations, providing preliminary support and stabilization that enables severe bevel angles to be machined without damaging the core structure
Solution Approach 2:
The pourable foam acts as an intermediary support material during machining operations, stabilizing the honeycomb core structure and enabling higher feed rates and more complex contours to be machined efficiently
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 reduces repair time and costs, enhances bonding between dissimilar materials, and stabilizes honeycomb cores during autoclave curing, allowing for efficient manufacturing with reduced weight penalties and improved structural integrity.
Implementation Method 1
position a first core member adjacent to a second core member; pour the foam mixture into the cavity so that the foam mixture expands and rises into the splicing area
Data Source
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AI summary
A method (401) of the present disclosure includes of repairing a core stiffened structure with structural foam. Another method (1201) includes splicing core members together using structural foam. Another method (1701) includes joining a core member to a structure using structural foam. Another method (1901) includes using structural foam to stabilize a core member during a machining process. Another method (2901) includes stabilizing a core member with structural foam to prevent the core member from crushing in autoclave pressure. The present disclosure further includes a core stiffened structure have a core member with structural foam therein.