Variable Rigidity Corner Fillet for Composite Stress Management

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Solution Overview

Problem

The noodle-shaped corner filler in composite structures has constant rigidity, making it difficult to adjust to varying pull-off loads, leading to increased stress during displacement.

Innovation Solution

A design method for the corner fillet part that adjusts rigidity by varying the content and type of resin and rigidity materials, such as carbon fibers, and modifying the shape or size, to match the specific stress conditions, allowing for adaptable behavior under different pull-off stresses.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the rigidity of the noodle-shaped corner filler is increased to function as a strength member, then the structural strength is improved, but the stress increases when the corner filler follows the displacement of the part

Engineering Contradiction:
Improvestructural strengthVSAvoidstress
Core Design Contradiction:
StrengthVSStress or pressure

Solution Approach 1:

The patent applies parameter changes by varying the rigidity of the corner filler through changes in material composition (resin content, fiber orientation, fiber type) to match the specific stress conditions at different locations. This allows the corner filler to have high rigidity where pull-off loads are low to function as a strength member, and low rigidity where pull-off loads are high to reduce stress during displacement.

Inventive Principle:
Principle #35Parameter changes

2Ease of manufacture

If the rigidity of the noodle-shaped corner filler is kept constant to simplify manufacturing, then the manufacturing process is simplified, but it becomes difficult to adjust the rigidity according to different parts of the structure

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidrigidity adjustability
Core Design Contradiction:
Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The patent applies local quality by making different parts of the corner filler have different rigidity characteristics. Specifically, the rigidity is varied according to the local stress conditions, with regions experiencing high pull-off loads having lower rigidity and regions with low pull-off loads having higher rigidity. This is achieved through varying resin content, fiber orientation, or fiber type in different regions.

Inventive Principle:
Principle #3Local quality

3Stability of the object's composition

If the corner filler is made with high rigidity materials to ensure structural integrity, then the structural integrity is improved, but the corner filler cannot follow large displacements of the part

Engineering Contradiction:
Improvestructural integrityVSAvoiddisplacement following capability
Core Design Contradiction:
Stability of the object's compositionVSAdaptability or versatility

Solution Approach 1:

The patent applies parameter changes by adjusting the material parameters of the corner filler (resin content, fiber orientation, fiber type) to achieve the appropriate balance between structural integrity and displacement following capability. In regions requiring high displacement following, the corner filler has lower rigidity with higher resin content or more flexible fiber arrangements, while maintaining structural integrity in regions where high rigidity is needed.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3210764B1Composite structure, aircraft, and method for designing corner fillet section
Publication Date: 2019.06.19 MITSUBISHI HEAVY IND LTD
  • EP3210764B1 patent drawingFigure 1~2
  • EP3210764B1 patent drawingFigure 3~4
  • EP3210764B1 patent drawingFigure 5~6

AI summary

A composite structure (10) provided with a first composite member (11), a second composite member (12) joined to the first composite member (11), and a corner fillet section (13) disposed in a corner section (15) formed by the first composite member (11) and the second composite member (12), wherein the rigidity of the corner fillet section (13) is adjustable, and adjusting the rigidity of the corner fillet section (13) adjusts peeling stress imparted to the corner section (15). Reducing the rigidity of the corner fillet section (13) reduces the peeling stress imparted to the corner section (15).