Preform Design for Resin Impregnation in Composite Materials

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Solution Overview

Problem

The existing methods for manufacturing fiber-reinforced resin composite materials using preforms often result in insufficient resin feeding, leading to voids and variations in impact resistance due to inadequate impregnation of the resin composition within the preform.

Innovation Solution

A preform design featuring a stack of fiber materials with alternating layers of high-melting-point reinforcing fibers and aliphatic polyamide fibers, where the aliphatic polyamide fibers have a core and a sheath with a melting point difference, allowing for effective resin impregnation and fusion bonding to prevent void formation and enhance impact resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a preform with fiber materials and non-woven fabric is used for manufacturing fiber-reinforced resin composite materials, then the structural integrity and reinforcement are improved, but insufficient resin feeding occurs leading to voids and variations in impact resistance

Engineering Contradiction:
Improveimpact resistanceVSAvoidresin impregnation uniformity
Core Design Contradiction:
StrengthVSManufacturing precision

Solution Approach 1:

A flow control member is introduced as an intermediary component between the resin injection system and the fiber material layers. This member includes through-holes that serve as controlled pathways for resin flow, ensuring uniform distribution of resin throughout the preform and preventing void formation while maintaining structural integrity

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The flow control member utilizes a porous structure with specifically designed through-holes to regulate resin flow. The porous configuration allows controlled permeation of resin through the member, ensuring adequate impregnation of fiber materials while preventing resin starvation and void formation

Inventive Principle:
Principle #31Porous materials

2Quantity of substance

If resin composition is filled into the preform space, then the composite material is formed, but insufficient feeding of resin composition causes void formation inside the composite material

Engineering Contradiction:
Improveresin composition fillingVSAvoidvoid formation
Core Design Contradiction:
Quantity of substanceVSReliability

Solution Approach 1:

The flow control member acts as a mediator that distributes resin composition uniformly across the preform. The through-holes in this member create controlled flow paths that ensure adequate resin reaches all fiber material layers, preventing void formation and ensuring complete impregnation

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The resin injection process utilizes controlled parameter changes including temperature and pressure adjustments. The resin is heated to appropriate temperatures to reduce viscosity and improve flow characteristics, while injection pressure is carefully controlled to ensure complete filling without causing defects

Inventive Principle:
Principle #35Parameter changes

3Stability of the object's composition

If fibers with core and sheath structure are used in the non-woven fabric, then the fiber material structure is enhanced, but the melting point difference between core and sheath requires precise temperature control

Engineering Contradiction:
Improvefiber material structureVSAvoidmelting point control
Core Design Contradiction:
Stability of the object's compositionVSTemperature

Solution Approach 1:

The manufacturing process utilizes controlled temperature changes that exploit the melting point difference between core and sheath fibers. Temperature is precisely controlled to melt the lower-melting-point sheath material while maintaining the structural integrity of the higher-melting-point core fibers, achieving desired fiber reconfiguration without compromising overall structure

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The process leverages phase transitions of the sheath material from solid to liquid state at its melting point. This controlled melting allows the sheath fibers to redistribute and bond adjacent fiber layers together, while the core fibers maintain their structural framework, achieving enhanced composite structure through selective phase change

Inventive Principle:
Principle #36Phase transitions

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 manufacturing of fiber-reinforced resin composite materials with high impact resistance by ensuring complete resin impregnation and reducing variations, thereby improving the material's mechanical properties.

Implementation Method 1

The sheath includes a resin having a melting point lower than a melting point of the core

Methodology Applied
Scientific EffectMelting: Melting

Data Source

PatentEP3771541B1Preform, fiber-reinforced resin composite material, and method of manufacturing fiber-reinforced resin composite material
Publication Date: 2024.02.14 SUBARU CORP
  • EP3771541B1 patent drawingFigure 1~2
  • EP3771541B1 patent drawingFigure 3~4
  • EP3771541B1 patent drawingFigure 5~6

AI summary

A preform includes a stack of a plurality of fiber materials. The fiber materials each include a first fiber layer including a reinforcing fiber and having a sheet shape, in which the reinforcing fiber has a melting point and a tensile strength that are higher than a melting point and a tensile strength of an aliphatic polyamide fiber, and a second fiber layer including the aliphatic polyamide fiber and having a sheet shape, and provided on at least one of surfaces of the first fiber layer. The aliphatic polyamide fiber includes a first polyamide resin and a second polyamide resin having a melting point higher than a melting point of the first polyamide resin by 7 degrees centigrade to 50 degrees centigrade.