Pourable Structural Foam Repair for Honeycomb Core
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Solution Overview
Problem
Conventional methods for repairing and splicing honeycomb core stiffened structures are time-consuming, expensive, and require multiple curing and bonding processes, and are inadequate for non-compatible materials, while machining and autoclave curing processes are inefficient and labor-intensive.
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, rigid, and flexible interface that supports machining and autoclave curing, eliminating the need for specialized tooling and thermal equipment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional adhesive bonding methods are used to repair honeycomb core, then bonding strength is achieved, but repair time and cost increase significantly
Solution Approach 1:
The patent changes the fundamental parameter of the bonding method from adhesive-based to foam-based expansion. The foam expands in situ to fill the cavity and bond to the honeycomb core, eliminating the need for separate adhesive application and curing steps. This parameter change reduces repair time while maintaining bonding strength through the foam's adhesion properties and expansion pressure.
Solution Approach 2:
The foam system performs multiple functions automatically: it expands to fill the cavity, bonds to the honeycomb core, and provides structural support without requiring external intervention for adhesive application or curing monitoring. The foam's chemical reaction and physical expansion occur autonomously after injection, reducing labor time and complexity.
2Stability of the object's composition
If multiple curing and bonding processes are used for repair, then structural integrity is maintained, but manufacturing complexity increases
Solution Approach 1:
The patent merges multiple separate processes (adhesive application, cavity filling, curing) into a single foam injection and expansion operation. The foam simultaneously provides bonding, cavity filling, and structural support functions, reducing the number of process steps and equipment required while maintaining structural integrity through the foam's composite properties.
Solution Approach 2:
The foam material serves multiple functions: it acts as an adhesive, a cavity filler, a structural support, and a bonding agent all in one. This multi-functionality eliminates the need for separate materials and processes for each function, simplifying the manufacturing procedure while ensuring structural integrity through the foam's engineered properties.
3Stability of the object's composition
If low feed rate machining is used to prevent honeycomb core damage, then core stability is maintained, but machining productivity decreases
Solution Approach 1:
The foam is injected and expanded into the honeycomb core cavity before the machining operation. This preliminary action provides internal support and stabilization to the core structure, allowing subsequent machining to proceed at higher feed rates without risking core damage. The foam acts as a protective scaffold during the machining process.
4Reliability
If conventional splicing with adhesive is used, then material compatibility is achieved, but process time and cost increase
Solution Approach 1:
The patent changes the bonding mechanism from adhesive chemistry to foam expansion and adhesion. The foam's expansion pressure and chemical bonding properties enable splicing of non-compatible materials that cannot be bonded with conventional adhesives. This parameter change reduces splicing time while expanding material compatibility to include previously incompatible material combinations.
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, allows for efficient splicing of non-compatible materials, and stabilizes honeycomb cores during machining and autoclave curing, enabling faster and more accurate manufacturing with reduced weight penalties.
Implementation Method 1
The foam is allowed to expand and fill the cavity
Implementation Method 2
The foam is allowed to cure
Data Source
AI summary
A method of the present disclosure includes of repairing a core stiffened structure with structural foam. Another method includes splicing core members together using structural foam. Another method includes joining a core member to a structure using structural foam. Another method includes using structural foam to stabilize a core member during a machining process. Another method 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.