Laminated Composite Structures with Interlaminar Corrugations

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Solution Overview

Problem

Laminated composite structures in aircraft applications are susceptible to impact damage, particularly at exposed edges, leading to internal damage like fiber breakage and delamination, which is difficult to detect and increases manufacturing costs and weight.

Innovation Solution

Incorporating interlaminar corrugations with a sinusoidal profile into the composite structure, formed during the manufacturing process using a laminate assembly with gap elements and a pressurizing system to enhance impact resistance without adding materials or manufacturing steps.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If laminated composite structures are used to achieve high strength and low weight, then structural performance is improved, but susceptibility to impact damage at exposed edges increases

Engineering Contradiction:

Improvestructural performanceVSAvoidimpact damage susceptibility

Core Design Contradiction:

StrengthVSObject-affected harmful factors

Solution Approach 1:

The patent applies curvature by forming corrugations (curved undulations) within the laminate layers at the exposed edges. These corrugations transform the flat, vulnerable edge surface into a curved, energy-dissipating structure that resists impact damage while maintaining the high strength-to-weight ratio of composite materials

Inventive Principle:

Principle #14Spheroidality (Curvature)

2Object-affected harmful factors

If edge covering devices are added to protect exposed edges, then impact damage resistance is improved, but manufacturing complexity and cost increase

Engineering Contradiction:

Improveimpact damage resistanceVSAvoidmanufacturing complexity

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent merges the protective function with the existing laminate structure by forming corrugations directly within the laminate layers during the manufacturing process. This integration eliminates the need for separate edge covering devices and their associated manufacturing steps, reducing complexity while maintaining impact damage resistance

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The laminate structure provides its own edge protection through self-formed corrugations that are created during the normal manufacturing process. The structure serves both its primary structural function and its protective function simultaneously, without requiring additional external protective elements

Inventive Principle:

Principle #25Self-service

3Object-affected harmful factors

If structural overwraps and stitching are applied to improve damage resistance, then impact damage resistance is improved, but manufacturing time and cost increase

Engineering Contradiction:

Improveimpact damage resistanceVSAvoidmanufacturing efficiency

Core Design Contradiction:

Object-affected harmful factorsVSProductivity

Solution Approach 1:

The protective corrugations are formed during the laminate manufacturing process itself, before the structure is put into service. This preliminary formation of protective features eliminates the need for subsequent overwrap application or stitching operations, maintaining manufacturing efficiency while achieving damage resistance

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS11801656B2Laminated composite structures with interlaminar corrugations to improve impact damage resistance

Publication Date: 2023.10.31 THE BOEING CO

AI summary

There is provided a laminated composite structure having improved impact damage resistance and improved strength. The laminated composite structure has a plurality of stacked layers of a composite material. The plurality of stacked layers have one or more interlaminar corrugations formed within the plurality of stacked layers. Each interlaminar corrugation has a substantially sinusoidal shaped profile, and has a depth and a length dependent on a size of the laminated composite structure formed. The laminated composite structure with the one or more interlaminar corrugations has improved strength and improved impact damage resistance at an exposed edge of the laminated composite structure, when the exposed edge is subjected to an impact force.