Trailing Edge Flap Waffle Grid Composite Structure

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Solution Overview

Problem

Existing trailing edge flaps for aircraft wings are constructed with numerous parts and fasteners, leading to time-consuming manufacturing processes, increased weight, and higher costs due to extensive handling and material usage.

Innovation Solution

The construction of a trailing edge flap using nested layers of pre-preg composite material with a minimized internal support structure, featuring a folded configuration that reduces the number of stiffening elements and fasteners, and incorporates polygonal holes to remove material and minimize weight, employing a method that involves laying up layers around a central mandrel and subsequent autoclave curing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If traditional aluminum skins with many internal stiffening elements and fasteners are used, then structural strength is maintained, but manufacturing time and complexity increase significantly

Engineering Contradiction:
Improvestructural strengthVSAvoidmanufacturing time
Core Design Contradiction:
StrengthVSProductivity

Solution Approach 1:

The patent combines multiple separate components (skins, stiffening elements, fasteners) into a single integrated composite laminate structure. The nested layers of pre-preg composite material are cured together in an autoclave to form a monolithic structure that eliminates the need for separate fasteners and reduces manufacturing steps while maintaining structural strength.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The invention uses pre-preg composite materials with fiber reinforcement embedded in a matrix material to create a structure that provides both strength and stiffness. The composite laminate structure replaces traditional aluminum construction, offering comparable or superior mechanical properties with reduced weight and simplified manufacturing.

Inventive Principle:
Principle #40Composite materials

2Strength

If many internal stiffening elements and fasteners are used, then structural integrity is maintained, but flap weight increases

Engineering Contradiction:
Improvestructural integrityVSAvoidflap weight
Core Design Contradiction:
StrengthVSWeight of moving object

Solution Approach 1:

The stiffening function is integrated into the laminate structure itself through the nested layers and folding patterns, eliminating the need for separate stiffening elements. This integration reduces the total number of components and their associated weights while maintaining the necessary structural rigidity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent removes unnecessary material from the structure by using a minimized internal support structure. By extracting only the essential support elements needed for structural integrity and incorporating them directly into the laminate design, the overall weight is reduced compared to traditional constructions with numerous discrete stiffeners.

Inventive Principle:
Principle #2Taking out (Extraction)

3Strength

If numerous parts and fasteners are used, then structural strength is maintained, but manufacturing complexity and cost increase

Engineering Contradiction:
Improvestructural strengthVSAvoidmanufacturing complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The patent merges multiple manufacturing operations into a single autoclave curing process. The nested layers are assembled in a folded configuration and then cured together, eliminating the need for separate assembly steps for fasteners and stiffening elements. This integration dramatically reduces manufacturing complexity and the number of handling operations required.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The laminate is designed with nested layers that can be separately prepared and then assembled in a systematic folded configuration. This segmentation allows for modular preparation of layers while achieving an integrated final structure, reducing overall manufacturing complexity through organized modularity.

Inventive Principle:
Principle #1Segmentation

4Strength

If traditional multi-component construction is used, then structural strength is ensured, but handling and assembly time increase

Engineering Contradiction:
Improvestructural strengthVSAvoidhandling and assembly time
Core Design Contradiction:
StrengthVSLoss of time

Solution Approach 1:

The patent combines multiple components into a single integrated laminate structure that is manufactured as one piece in the autoclave. This eliminates the need for separate handling and assembly of skins, stiffeners, and fasteners, dramatically reducing the time and labor required for assembly while maintaining all necessary structural functions.

Inventive Principle:
Principle #5Merging (Combining)

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 significantly reduces manufacturing time, costs, and weight of the trailing edge flap while maintaining structural integrity, simplifying the laminate design and minimizing internal support structures.

Implementation Method 1

subsequent autoclave curing

Methodology Applied
Scientific EffectHeat treatment: Heat Treatment

Implementation Method 2

autoclave curing

Methodology Applied
Scientific EffectCompression: Compression

Data Source

PatentEP3812263B1Trailing edge flap having a waffle grid interior structure
Publication Date: 2025.03.26 THE BOEING CO
  • EP3812263B1 patent drawingFigure 1~2
  • EP3812263B1 patent drawingFigure 3~4
  • EP3812263B1 patent drawingFigure 5~9

AI summary

An aircraft flap is constructed of nested layers of composite material in the aircraft flap that include an inner layer, a middle layer and an outer layer. The aircraft flap is constructed with the inner layer laid up around a central mandrel, the middle layer laid up around the middle layer and the outer layer laid up around the middle layer. The inner layer, the middle layer and the outer layer are co-cured on the mandrel, removed from the mandrel and then assembled together with the inner layer formed in a folded over configuration around a hollow interior volume of the aircraft flap, the middle layer formed in a folded over configuration over the inner layer, and the outer layer formed in a folded over configuration around the middle layer.