Induction-Cured Radius Filler for Composite Structures

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing methods for forming radius fillers in composite structures often result in thermal induced stresses, leading to cracking issues due to co-curing processes, and add complexity and time to the manufacturing process with pre-cured fillers.

Innovation Solution

A method involving a radius filler with heating elements embedded within a composite material, inductively heated to cure the filler before surrounding composite structures, reducing thermal stresses and simplifying the manufacturing process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If radius filler is co-cured with surrounding composite lamina, then manufacturing process is simplified, but thermal induced stresses cause cracking within the filler

Engineering Contradiction:

Improvemanufacturing process simplicityVSAvoidfiller cracking resistance

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The curing process is segmented into two distinct phases: first curing the radius filler independently using induction heating, then curing the surrounding composite structures. This segmentation allows the filler to achieve full strength before being constrained by the surrounding structures, eliminating thermal induced stresses and cracking while maintaining manufacturing simplicity.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The radius filler is cured in advance before the surrounding composite structures are cured. By performing the filler curing action preliminarily, the filler reaches its final dimensional state and strength properties before the surrounding structures impose thermal and mechanical constraints, preventing stress-induced cracking.

Inventive Principle:

Principle #10Preliminary action

2Reliability

If pre-cured radius fillers are used to reduce thermal induced stresses, then filler cracking is reduced, but manufacturing process complexity and time increase

Engineering Contradiction:

Improvefiller cracking resistanceVSAvoidmanufacturing process complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The radius filler integrates embedded heating elements directly into its composite material structure, merging the filler and heating system into a single component. This allows in-situ curing of the filler using induction heating, eliminating the need for separate pre-curing operations and reducing manufacturing complexity while preventing cracking.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

Traditional external heating methods are replaced with induction heating that directly induces current within the embedded heating elements of the filler. This substitution enables precise, localized, and rapid curing of the filler in its final position, simplifying the manufacturing process while ensuring crack-free curing by eliminating thermal gradients from external heating.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Reliability

If pre-cured radius fillers are used, then thermal induced stresses are reduced, but production cycle time increases

Engineering Contradiction:

Improvefiller cracking resistanceVSAvoidproduction cycle time

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

Induction heating replaces traditional external heating methods, enabling direct and rapid heating of the filler through induced currents in embedded elements. This substitution dramatically reduces the time required to cure the filler compared to conventional external heating, thereby shortening the production cycle while preventing cracking through uniform internal heating.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The embedded heating elements enable continuous and uniform heating throughout the filler volume simultaneously, eliminating the sequential heating process required by external methods. This continuous internal heating action reduces curing time significantly while ensuring uniform temperature distribution that prevents thermal induced stresses and cracking.

Inventive Principle:

Principle #20Continuity of useful action

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 minimizes thermal induced stresses and cracking, enhances structural performance, and streamlines the manufacturing process by locally curing the radius filler before curing the surrounding structures, while maintaining efficiency and cost-effectiveness.

Implementation Method 1

The radius filler is inductively heated by inducing a current within the number of heating elements

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

The radius filler is cured by inductively heating the number of heating elements within the radius filler

Methodology Applied

Scientific EffectJoule heating: Joule Heating

Data Source

PatentUS10225891B2In-situ induction cured radius filler

Publication Date: 2019.03.05 THE BOEING CO

AI summary

A method for manufacturing a radius filler. The radius filler having a desired cross-sectional shape is formed. The radius filler has a composite material and a number of heating elements located within the composite material. The radius filler is positioned in a channel formed by a plurality of composite structures. The radius filler is inductively heated by inducing a current within the number of heating elements.