Composite Ply Stabilizing Grip Strips for Autoclave Core Crush
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Solution Overview
Problem
Composite sandwich structures with thick, chamfered cores face challenges in stabilizing plies during autoclave curing, leading to ply slippage and core crush due to large side loads and reduced resin viscosity, which existing methods like film adhesives and tie-down straps fail to adequately address without increasing weight.
Innovation Solution
A stabilizing mechanism comprising lower and upper grip strips with protrusions mounted to the tool, engaging the plies to prevent movement, and a compressive force mechanism to enhance engagement, reducing core crush without adding weight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If film adhesive and fiberglass sheet are applied around the border of the composite panel to stabilize the core, then core stability is improved, but additional weight is added to the structure
Solution Approach 1:
The invention extracts and removes the harmful fiberglass sheet that extends across the core surface, replacing it with a stabilizing mechanism that only engages the plies at the perimeter regions where stabilization is actually needed, thereby eliminating unnecessary weight
Solution Approach 2:
The invention introduces a stabilizing mechanism comprising grip strips with engagement features that act as an intermediary between the plies and the tool, providing core stabilization through mechanical engagement rather than through adhesive and fiberglass materials
2Stability of the object's composition
If tie down straps are applied along the perimeter of the composite layup to prevent core crush, then core stability is improved, but they are ineffective against large side forces on chamfers of large surface area
Solution Approach 1:
The invention transitions from static tie down straps to a dynamic stabilizing mechanism where grip strips with protrusions actively engage the plies, allowing the system to adapt and respond to varying side forces during autoclave curing, particularly effective on chamfers of large surface area
Solution Approach 2:
The stabilizing mechanism combines multiple functional elements (grip strips, protrusions, engagement features) into a composite system that provides superior performance compared to single-material tie down straps
3Strength
If autoclave pressure is applied to cure and bond composite materials, then bonding strength is improved, but ply slippage and core crush occur due to large side loads
Solution Approach 1:
The invention applies preliminary anti-action by providing a stabilizing mechanism that counteracts the harmful side loads generated during autoclave curing before ply slippage and core crush can occur, allowing the full autoclave pressure to be applied for optimal bonding
Solution Approach 2:
The invention converts the harmful side forces that cause ply slippage into beneficial compressive forces by using the grip strips and protrusions to transform lateral movement into vertical compression, which actually improves bonding between plies and core
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
Effectively prevents ply movement and core crush in composite structures with thick, chamfered cores under autoclave pressure, maintaining structural integrity and weight efficiency.
Implementation Method 1
The heating of the plies between which the core is sandwiched may reduce the viscosity of the resin that is in contact with the core and which may reduce friction and further facilitate ply slippage
Implementation Method 2
a compressive force mechanism to enhance engagement, reducing core crush without adding weight
Data Source
AI summary
A stabilizing mechanism for resisting relative movement of upper and lower laminates of a composite structure having a core comprises a lower grip strip and at least one upper grip strip. The lower grip strip may be mounted to a tool upon which the composite structure may be processed. The lower grip strip may include an outer surface having at least one engagement feature for engaging at least one of the upper and lower laminates which make up the composite structure. The upper grip strip may have opposing outer surfaces which may include at least one engagement feature for engaging the lower strip and at least one of the upper and lower laminates.