Resin Composite Corner Stress Reduction via Cell Flatness

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Solution Overview

Problem

Resin composites with three-dimensional core materials experience stress concentration issues, particularly at corner sections where surfaces adjoin at angles less than 180 degrees, leading to potential mechanical weakness.

Innovation Solution

The resin composite is designed with a core material having a three-dimensional shape where the cell shape in corner sections is adjusted to reduce stress concentration by increasing the flatness ratio of cells to 20% or more, and the thickness of the corner section is made thicker than the adjacent surfaces, allowing for better distribution of stress.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Shape

If the core material has a three-dimensional shape with corner sections, then the resin composite can achieve complex shapes suitable for automotive and aerospace applications, but stress concentration occurs at the corner sections where surfaces adjoin at angles less than 180 degrees

Engineering Contradiction:
Improvethree-dimensional shapeVSAvoidmechanical strength
Core Design Contradiction:
ShapeVSStrength

Solution Approach 1:

The invention applies different cell structures to different regions of the core material. Specifically, the corner sections have cells with a flatness ratio of 70% or more (nearly plate-like), while other regions can have different cell characteristics. This local differentiation addresses stress concentration at corners without compromising the overall three-dimensional shape and functional performance of the resin composite.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The invention changes the physical parameter of cell flatness ratio in specific regions to solve the stress concentration problem. By controlling the cell flatness ratio to be 70% or more in corner sections through specific foam expansion processes, the structural parameter is optimized to distribute stress more evenly, thereby improving mechanical strength while maintaining the three-dimensional shape.

Inventive Principle:
Principle #35Parameter changes

2Strength

If the core material uses a simple plate-like structure, then stress distribution is more uniform, but the resin composite loses the ability to achieve complex three-dimensional shapes required for lightweight design in transportation equipment

Engineering Contradiction:
Improvestress distributionVSAvoidthree-dimensional shape
Core Design Contradiction:
StrengthVSShape

Solution Approach 1:

The invention combines simple plate-like cell structures in critical stress areas (corners with flatness ratio ≥70%) with three-dimensional shaping in other regions. This allows the core material to achieve complex shapes while maintaining uniform stress distribution in the corner sections where it is most needed.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The invention segments the core material into different functional regions: corner sections with high flatness ratio cells for stress distribution, and other regions with varying cell structures for achieving complex three-dimensional shapes. This segmentation allows each region to optimize its local function while contributing to the overall performance of the resin composite.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP3002119B1Resin composite and process for producing resin composite
Publication Date: 2020.01.08 SEKISUI PLASTICS CO LTD
  • EP3002119B1 patent drawingFigure 1A~1C
  • EP3002119B1 patent drawingFigure 2~3
  • EP3002119B1 patent drawingFigure 4~5

AI summary

A resin composite in which the flatness ratio of cells in a corner section of a core material is 20% or more is provided.