Modifier Placement in Resin-Rich Pockets to Mitigate Microcracking
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Solution Overview
Problem
Composite structures experience microcracking due to thermal expansion differences between resin and fibers, leading to undesirable cracking and weight increases that reduce performance efficiency, particularly in applications like aircraft.
Innovation Solution
Incorporating modifiers with distinct characteristics into resin-rich pockets of composite structures to mitigate crack initiation and growth by altering thermal expansion, toughness, and cure shrinkage, thereby reducing thermally-induced stresses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the structural load-carrying capability is increased to accommodate microcracking, then the reliability is improved, but the weight increases
Solution Approach 1:
The patent applies local quality by placing modifiers specifically in resin-rich pockets rather than uniformly throughout the composite structure. This targeted approach addresses microcracking in high-risk areas while maintaining the original composite properties in load-bearing regions, thus improving microcracking resistance without adding unnecessary weight.
Solution Approach 2:
The patent uses composite materials by incorporating modifiers with different CTE characteristics into the resin-rich pockets. These modifiers create a localized composite material system that compensates for thermal expansion differences between resin and fibers, reducing thermally-induced stresses and microcracking without requiring overall structural reinforcement.
2Reliability
If modifiers are incorporated into resin-rich pockets to mitigate microcracking, then the reliability is improved, but the device complexity increases
Solution Approach 1:
The patent applies preliminary action by incorporating modifiers into the resin system before the composite manufacturing process. This allows modifiers to be pre-positioned in resin-rich pockets during standard manufacturing operations, avoiding the need for additional post-processing steps or complex modification procedures.
Solution Approach 2:
The patent employs self-service by designing the modifier incorporation process to work within the existing manufacturing workflow. The modifiers are automatically positioned in resin-rich pockets through the normal resin infusion and curing process, eliminating the need for separate intervention or complex control systems.
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
The targeted placement of modifiers in resin-rich pockets reduces microcracking, maintains load-carrying performance, and minimizes weight increases, enhancing the structural integrity and efficiency of composite structures.
Implementation Method 1
The resin may have a coefficient of thermal expansion (CTE) that may be different than the CTE of the fibers... The difference in CTE may result in the resin and fibers contracting by different amounts when the temperature of the composite structure is cooled after curing... The modifier may have a coefficient of thermal expansion (CTE) that is different than the resin CTE
Implementation Method 2
The modifier may have a cure shrinkage that is different than the resin cure shrinkage
Data Source
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AI summary
A composite structure may include a resin, a fiber at least partially embedded within the resin, and one or more resin-rich pockets associated with the fiber. The composite structure may include modifiers in the one or more resin-rich pockets. The modifier may have at least one modifier characteristic that is different than a resin characteristic for altering the resin characteristics within the resin-iich pockets and thereby mitigating or preventing crack initiation or crack growth within the resin-rich pockets of the composite structure.