Thermoplastic Particle Placement for Composite Interface Toughness

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Solution Overview

Problem

Composite structures often exhibit voids at interfaces between structural members and filler members, which can weaken the structure, and existing methods for filling these voids do not adequately enhance the toughness of the filler member-to-surrounding structure interfaces.

Innovation Solution

The method involves depositing thermoplastic particles onto the surfaces of filler and structural members, positioning them proximate to the interfaces, and infusing the assembly with a thermoset resin to cure and strengthen the interfaces.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If voids are filled with pre-formed filler members to maximize strength and rigidity, then the structural integrity is improved, but the interface toughness between filler member and surrounding structure remains insufficient

Engineering Contradiction:

Improvestructural integrityVSAvoidinterface toughness

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The patent applies local quality by concentrating thermoplastic particles specifically at the interface regions between filler members and structural members, rather than uniformly distributing them throughout the void. This localized placement ensures that the critical interface zones have enhanced toughness properties where needed most, while maintaining overall structural integrity.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent employs composite materials by combining thermoset resin (providing structural strength) with thermoplastic particles (providing interface toughness). This dual-material approach creates a composite system where each material contributes its superior properties to the overall structure, resolving the contradiction between strength and interface toughness.

Inventive Principle:

Principle #40Composite materials

2Reliability

If thermoplastic particles are deposited onto filler member surfaces, then the interface toughness is enhanced, but the manufacturing process complexity increases

Engineering Contradiction:

Improveinterface toughnessVSAvoidmanufacturing process complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by depositing thermoplastic particles onto filler member surfaces before the actual void-filling operation. This advance preparation ensures that when the filler members are positioned, the interface toughness enhancement is already in place, simplifying the subsequent assembly process rather than requiring complex post-assembly modifications.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The thermoplastic particles act as an intermediary material between the filler member and the surrounding structural members. This intermediary layer facilitates improved bonding and toughness at the interface, while the particles themselves can be applied using relatively simple deposition techniques, balancing performance enhancement with manufacturing simplicity.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 enhances the toughness of the interfaces by increasing the energy absorption capacity, thereby improving the overall strength and rigidity of the composite structure.

Implementation Method 1

depositing a plurality of thermoplastic particles onto at least one of a surface of a filler member and a surface of a structural member

Methodology Applied

Scientific EffectAdhesion: Adhesive

Implementation Method 2

infusing the preform with a thermoset resin and curing the thermoset resin

Methodology Applied

Scientific EffectPolymerization: Photopolymerisation

Data Source

PatentUS11097495B2Composite structures and methods for manufacturing composite structures

Publication Date: 2021.08.24 THE BOEING CO

AI summary

A method for manufacturing a composite structure. The method includes depositing a plurality of thermoplastic particles onto at least one of a surface of a filler member and a surface of a structural member. The method further includes assembling the filler member with the structural member such that the plurality of thermoplastic particles are disposed proximate an interface between the filler member and the structural member.