Foam Core Sandwich Strut Reinforcement via Fibrous Boundary

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Solution Overview

Problem

Sandwich structures with foam cores reinforced by fibers and resin infiltration face reduced mechanical strength when localized working occurs, leading to impaired mechanical properties in regions beyond the worked area due to disconnected struts.

Innovation Solution

A method involving the creation of a two-dimensional gap within a working region in the foam material, where a fibrous sheet-like material encloses the gap and a strut is introduced from outside the region, connecting both ends within the foam material, ensuring the strut's reinforcing effect is retained during localized working without compromising mechanical properties outside the working area.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If struts are introduced into the foam material to reinforce it, then the mechanical strength is improved, but localized working causes struts to be severed or detached, reducing mechanical strength in enlarged regions

Engineering Contradiction:

Improvemechanical strengthVSAvoidmechanical property stability in enlarged region

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The foam material is divided into a working region and an enlarged region, with the fibrous sheet-like material creating a distinct boundary layer. This segmentation allows struts to be strategically positioned - some within the working region and others extending into the enlarged region - so that localized working operations only affect struts within the working region boundary, preserving strut functionality in the enlarged region.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The fibrous sheet-like material is introduced into the foam material before localized working operations. This preliminary action creates a protective boundary that defines the working region, ensuring that subsequent cutting or drilling operations will not inadvertently sever struts in the enlarged region, thus preserving the mechanical reinforcement in areas beyond the immediate work zone.

Inventive Principle:

Principle #10Preliminary action

2Adaptability or versatility

If a fibrous sheet-like material is introduced to define a working region, then localized working is enabled without impairing mechanical properties outside the region, but the device complexity increases

Engineering Contradiction:

Improvelocalized working capabilityVSAvoidstructure complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

A thin fibrous sheet-like material is introduced into the foam material to define the working region boundary. This thin film approach provides an effective barrier to protect struts in the enlarged region from being severed during localized working operations, while adding minimal structural complexity and maintaining the overall simplicity of the sandwich structure.

Inventive Principle:

Principle #30Flexible shells and thin films

3Strength

If struts run at different defined angles to provide reinforcement, then mechanical strength is improved, but localized working disrupts the strut configuration, causing mechanical property changes in enlarged regions

Engineering Contradiction:

Improvemechanical strengthVSAvoidstrut configuration stability

Core Design Contradiction:

StrengthVSStability of the object's composition

Solution Approach 1:

The foam material is segmented into working and enlarged regions using the fibrous sheet-like material as a boundary. This segmentation preserves the designed strut configuration in the enlarged region by preventing working operations from disrupting struts that run at different defined angles, maintaining the mechanical reinforcement integrity while allowing necessary localized working within the designated area.

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

Enables localized working within the specified region without impairing the mechanical properties of the reinforced foam material beyond the working area, providing stable reinforcement and anchoring of the strut within the resin matrix, allowing for effective mechanical stability and secure integration.

Implementation Method 1

After a resin infiltration process, the pierced regions contribute to the mechanical reinforcement of the basic foam material

Methodology Applied

Scientific EffectResin infiltration: Absorption (physical)

Implementation Method 2

the pierced regions contribute to the mechanical reinforcement of the basic foam material

Methodology Applied

Scientific EffectAdhesion: Adhesive

Data Source

PatentUS7891096B2Method for reinforcing a foam material as well as a sandwich component

Publication Date: 2011.02.22 AIRBUS OPERATIONS GMBH

AI summary

Provided is a method for reinforcing a foam material in which a working region is first prescribed. A gap that at least partially encloses the prescribed working region in a two-dimensional manner is created in the foam material. A strut is introduced into the foam material, extending from an entry surface of the foam material from outside the working region to at least the fibrous sheet-like material. From a further aspect, a sandwich component with a core which comprises a foam material is provided. A fibrous sheet-like material arranged in the foam material at least partially encloses a working region of the sandwich component in a sheet-like manner. At least one strut is incorporated in the foam material and extends from an entry surface of the foam material from outside the working region to at least the fibrous sheet-like material.