Composite Material Structure Thermal Expansion Matching
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Solution Overview
Problem
Composite material structures for aircraft components face strength degradation due to thermal stress caused by differences in thermal expansion ratios between fiber-reinforced fillers and structure components, leading to cracks or peeling.
Innovation Solution
A composite material structure and manufacturing method where both the structure and filler are made from laminated fiber-reinforced sheets with varying fiber directions, ensuring the same laminate ratios and orders, thereby matching thermal expansion ratios and reducing the likelihood of cracks or peeling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a filler is formed by shaping a fiber reinforced sheet having the fiber direction in a predetermined direction, then the filler can be manufactured by die molding or pultrusion molding, but the fiber direction of the filler becomes the same as a whole, resulting in different thermal expansion ratios compared to the structure component and causing thermal stress
Solution Approach 1:
The patent applies local quality by making the fiber direction in the filler non-uniform, specifically designing it to differ from the uniform fiber direction in conventional fillers. The fiber reinforced sheets in the filler are arranged so that their fiber directions vary, creating local variations in thermal expansion characteristics that match the multi-directional structure component, thereby reducing thermal stress while maintaining manufacturing feasibility
Solution Approach 2:
The patent uses composite materials by combining multiple fiber reinforced sheets with different fiber directions within the filler. This creates a composite structure within the filler itself, where sheets with fibers oriented in different directions (including directions intersecting the laminating direction) work together to achieve thermal expansion characteristics that match the structure component, resolving the thermal stress issue
2Adaptability or versatility
If the filler and structure component have different thermal expansion ratios, then they can be manufactured with different fiber configurations, but thermal stress occurs during heating or cooling, causing cracks or peeling
Solution Approach 1:
The patent applies parameter changes by modifying the fiber direction parameters of the fiber reinforced sheets in the filler. Specifically, it changes the fiber direction from the conventional uniform predetermined direction to varied directions that include directions intersecting the laminating direction. This parameter change in fiber orientation adjusts the thermal expansion ratio of the filler to match the structure component, preventing thermal stress-induced cracks or peeling while maintaining manufacturing flexibility
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 approach stabilizes the composite material structure by ensuring uniform thermal expansion, reducing strength degradation and maintaining structural integrity during heating or cooling.
Implementation Method 1
Fiber reinforced sheets has a property of less expanding in the fiber direction and easily expanding in a direction intersecting the fiber direction. Thus, the fiber reinforced sheet has different thermal expansion ratios depending on the direction.
Data Source
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AI summary
The disclosure intends to reduce strength degradation of a composite material structure. A composite material structure 10 includes a first structure component 11 curved at a curved portion 16 and a filler 13 provided in a clearance between the curved portion 16 and a second structure component 12 and attached to the curved portion 16. A plurality of fiber reinforced sheets included in the first structure component have a plurality of fiber reinforced sheets including a first fiber reinforced sheet whose fiber direction that is a fiber extending direction is an X-axis direction and having different fiber directions. The plurality of fiber reinforced sheets included in the filler 13 have the plurality of fiber reinforced sheets including the first fiber reinforced sheet and having different fiber directions. The ratio of the total length in a laminating direction of the first fiber reinforced sheet to the total length in the Z-axis direction of all the fiber reinforced sheets in the first structure component 11 is substantially the same as the ratio of the total length in the laminating direction of the first fiber reinforced sheet to the total length in the laminating direction of all the fiber reinforced sheets in the filler 13.