Composite Wingbox Panels with Foam Core for Warpage Control

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Solution Overview

Problem

Conventional composite aircraft wing panels are prone to warpage and defects due to incompatibility with prepreg tape, leading to increased weight, manufacturing inefficiencies, and reduced strength, which are not adequately addressed by the use of shims.

Innovation Solution

The introduction of a novel wing panel design featuring a split skin structure with foam pieces between composite face sheets, tailored for stiffness and structural efficiency, and a method of co-curing these components with resin in an autoclave to prevent warping and enhance structural integrity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If conventional composite panels with prepreg tape are used, then manufacturing is simplified, but warpage and structural defects occur

Engineering Contradiction:

Improvemanufacturing simplicityVSAvoidpanel flatness

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The panel is divided into multiple composite layers (first composite layer, second composite layer, third composite layer) separated by foam core material. This segmentation allows each layer to be optimized independently while the foam core prevents warpage by providing dimensional stability and separating the composite layers during manufacturing and assembly.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Foam core material is introduced as an intermediary element between the composite layers. This foam core acts as a mediator that prevents direct contact and warpage between layers while maintaining structural integrity. It also serves as a bonding surface for attaching stringers and other structural components.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Strength

If stringers are added to provide structural support, then strength is improved, but weight increases

Engineering Contradiction:

Improvepanel strengthVSAvoidwing weight

Core Design Contradiction:

StrengthVSWeight of moving object

Solution Approach 1:

Stringers are strategically positioned at specific locations where structural support is most needed rather than uniformly distributed. The foam core provides distributed support throughout the panel, allowing stringers to be minimized or eliminated in certain areas, thereby reducing weight while maintaining necessary strength.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The panel uses a composite construction combining foam core material with multiple composite layers. This composite structure provides high strength-to-weight ratio, as the foam core provides bulk and support while the thin composite layers provide skin strength and aerodynamic surface, reducing the need for heavy metal stringers.

Inventive Principle:

Principle #40Composite materials

3Manufacturing precision

If foam pieces are introduced to reduce warping, then manufacturing precision is improved, but device complexity increases

Engineering Contradiction:

Improvepanel flatnessVSAvoidpanel structure complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The foam core material serves multiple functions simultaneously: it acts as a warpage prevention layer, provides structural support, serves as a bonding surface for stringers, and maintains the separation between composite layers. This multi-functionality reduces the need for additional components, thereby limiting the increase in device complexity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

4Weight of moving object

If conventional composite panels are used, then weight is reduced, but strength is compromised due to warpage

Engineering Contradiction:

Improvepanel weightVSAvoidpanel strength

Core Design Contradiction:

Weight of moving objectVSStrength

Solution Approach 1:

The panel is segmented into multiple thin composite layers separated by foam core material. This segmentation allows the composite layers to remain thin and lightweight while the foam core provides the structural support and warpage prevention, achieving both weight reduction and strength maintenance.

Inventive Principle:

Principle #1Segmentation

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 design significantly reduces warping, increases panel strength, minimizes weight, and streamlines manufacturing processes, while providing the necessary stiffness for supersonic aircraft and regional aircraft applications.

Implementation Method 1

a plurality of foam pieces disposed between the outer face sheet and the inner face sheet, wherein the foam pieces reduce warping of the panels

Methodology Applied

Scientific EffectElasticity: Elasticity

Implementation Method 2

a method of co-curing these components with resin in an autoclave to prevent warping and enhance structural integrity

Methodology Applied

Scientific EffectAdhesive bonding: Adhesive

Data Source

PatentUS20220119092A1Composite thin wingbox architecture for supersonic business jets

Publication Date: 2022.04.21 THE BOEING CO

AI summary

An apparatus including one or more panels including an outer face sheet comprising a plurality of first composite materials; an inner face sheet comprising a plurality of second composite materials; and a plurality of foam pieces disposed between the outer face sheet and the inner face sheet, wherein the foam pieces reduce warping of the panels.