Pyramid Waffle Core Resisting Shear and Side-Loading

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Solution Overview

Problem

Existing acoustic core structures, such as honeycomb cores, are costly and provide inadequate resistance to shear stresses and side-loading, limiting their effectiveness in applications requiring robust sound absorption and structural integrity.

Innovation Solution

A pyramid waffle core structure formed from rows and columns of hollow pyramid-like structures, which are closed-off and provide a truss-like support, reducing manufacturing costs and enhancing resistance to transverse loads and shear stresses without the need for filling open spaces.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a honeycomb core structure is used, then high stiffness with respect to transverse loads is achieved, but resistance to shear stresses and side-loading is insufficient

Engineering Contradiction:
Improveresistance to shear stresses and side-loadingVSAvoidmanufacturing cost and complexity
Core Design Contradiction:
StrengthVSEase of manufacture

Solution Approach 1:

The core structure is segmented into individual pyramid-shaped cells arranged in a waffle pattern, where each cell is formed by folding and bonding ribbons. This segmentation allows for simplified manufacturing compared to traditional honeycomb structures while maintaining structural integrity and resistance to shear stresses.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent combines pyramid-shaped cellular structures with a waffle pattern configuration, creating a composite core structure that integrates both acoustic absorption properties and enhanced mechanical strength. The triangular geometry of the pyramids works synergistically with the waffle pattern to provide superior resistance to shear stresses and side-loading.

Inventive Principle:
Principle #40Composite materials

2Reliability

If open honeycomb spaces are filled to improve acoustic absorption, then sound dampening is enhanced, but manufacturing cost and process complexity increase

Engineering Contradiction:
Improveacoustic absorption performanceVSAvoidmanufacturing process complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The pyramid waffle core structure utilizes the inherent porosity of the pyramid-shaped cells to provide acoustic absorption. The closed-cell pyramid configuration creates tortuous flow paths for sound waves, enhancing acoustic dampening without requiring additional filling materials or complex manufacturing steps.

Inventive Principle:
Principle #31Porous materials

Solution Approach 2:

The patent extracts the acoustic absorption function from the traditional approach of filling honeycomb cells with additional materials and instead achieves sound dampening through the geometric configuration of the pyramid cells themselves. This eliminates the need for septum layers or cell-filling operations.

Inventive Principle:
Principle #2Taking out (Extraction)

3Reliability

If a traditional honeycomb core is used, then structural support is provided, but additional modifications are required for acoustic dampening which add expense

Engineering Contradiction:
Improveacoustic dampening effectivenessVSAvoidmanufacturing cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The pyramid waffle core structure serves multiple functions simultaneously: it provides structural support, acoustic absorption, and shear resistance all through a single integrated geometry. The pyramid-shaped cells inherently provide both mechanical strength and acoustic dampening properties, eliminating the need for separate modifications to achieve acoustic performance.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent creates a composite structure where the pyramid waffle pattern itself acts as both the structural framework and the acoustic dampening medium. The triangular geometry and three-dimensional configuration provide dual functionality, combining structural integrity with sound absorption capabilities in a single manufactured component.

Inventive Principle:
Principle #40Composite materials

Data Source

PatentEP2927904B1Pyramid waffle core structure and method of fabrication
Publication Date: 2019.01.02 THE BOEING CO
  • EP2927904B1 patent drawingFigure 1
  • EP2927904B1 patent drawingFigure 2
  • EP2927904B1 patent drawingFigure 3A~3B

AI summary

A structural core and associated method of forming such structure is disclosed. The structure includes a single layer of at least two rows of hollow pyramid-like structures. The hollow pyramid-like structures dampen acoustic noise and provide a trusslike structure that provides a high level of stiffness against transverse loads, shear stresses and side-loading. The hollow pyramid-like structures preferably have upward facing and downward facing open bases, and are formed in rows and columns. To aid in sound attenuation, the single layer is formed from a partially porous material, a woven thermoplastic, woven carbon fiber, fiberglass and paper. To provide additional structural integrity, the single layer is formed from a solid non-porous material such as a metal. The structural core may be included within outer panels to form acoustical or structural panels.