Composite Sandwich Base Panel for Indentation-Resistant ULDs

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Solution Overview

Problem

Existing unit load devices made from composite materials suffer from low compressive strength and susceptibility to plastic deformation, leading to local indentation failure and operational inefficiencies during transportation.

Innovation Solution

A composite sandwich structure incorporating high-strength microspheres within a matrix material, sandwiched between upper and lower fibre-reinforced layers, providing enhanced compressive strength and resistance to deformation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Weight of moving object

If low density core material is used to reduce weight, then weight decreases and stiffness-to-weight ratio improves, but compressive strength decreases leading to local indentation failure

Engineering Contradiction:
Improvebase panel weightVSAvoidcompressive strength
Core Design Contradiction:
Weight of moving objectVSStrength

Solution Approach 1:

The patent applies composite materials by combining foam core with dispersed particles (such as hollow microspheres, ceramic beads, or metal particles) to create a hybrid core structure. This composite approach allows the core to maintain low density from the foam while gaining compressive strength from the dispersed particles, thereby resolving the contradiction between weight reduction and compressive strength enhancement.

Inventive Principle:
Principle #40Composite materials

2Strength

If core stiffness is increased to prevent indentation, then compressive strength improves, but the panel cannot bend sufficiently around roller tips resulting in concentrated stress and core failure

Engineering Contradiction:
Improvecore compressive strengthVSAvoidpanel flexibility
Core Design Contradiction:
StrengthVSEase of operation

Solution Approach 1:

The patent applies local quality by creating a core structure with non-uniform properties - the foam matrix provides flexibility and energy absorption throughout, while dispersed particles are strategically distributed to provide localized stiffness and compressive resistance where needed. This allows different regions of the core to perform different functions, balancing overall flexibility with localized strength.

Inventive Principle:
Principle #3Local quality

3Strength

If fibre reinforcement is added to increase flexural stiffness, then resistance to bending improves, but the panel becomes more susceptible to fracture around roller tips due to excessive bending

Engineering Contradiction:
Improveflexural stiffnessVSAvoidresistance to fracture
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The patent applies composite materials by integrating fibre reinforcement into the foam core matrix, creating a composite core structure. The fibres provide tensile strength and crack resistance, while the foam matrix maintains flexibility and energy absorption. This composite approach allows the panel to achieve sufficient flexural stiffness without becoming brittle, thereby preventing fracture around roller tips while maintaining operational flexibility.

Inventive Principle:
Principle #40Composite materials

Data Source

PatentEP3307607B1A composite sandwich structure
Publication Date: 2025.12.24 FERGUSSONS ADVANCED COMPOSITE TECH
  • EP3307607B1 patent drawingFigure 1~2b
  • EP3307607B1 patent drawingFigure 3~5
  • EP3307607B1 patent drawingFigure 6~7

AI summary

The invention relates to a composite sandwich base panel for a Unit Load Device. The panel comprises an upper surface layer comprising fibre reinforcement material, a lower surface layer comprising fibre reinforcement material, and a central core section where at least the majority comprises a plurality of particles bound in a matrix material. The upper surface layer and lower surface layer are provided with a matrix material to bind them to the central core section.