Composite Railway Structural Element with Foam Core

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Solution Overview

Problem

The existing methods for producing structural elements of railway vehicles, such as longitudinal walls and floors, face challenges in achieving uniform rigidity, reducing the number of parts, and minimizing weight and aesthetic issues, as they often require complex assembly and use of metal materials with visible fasteners.

Innovation Solution

A method involving the use of composite material hollow sections connected by webs to form a closed section, with a foam core and ribs, allowing for a one-piece structural element with improved rigidity and reduced part count, using a matrix of thermosetting material mixed with continuous fibers, and eliminating visible fasteners.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If metal elements are assembled together by welding, riveting or bolting to form structural elements, then the structural element can be produced using conventional manufacturing methods, but the rigidity is reduced due to fixing elements passing through the elements and the number of parts increases

Engineering Contradiction:
Improveconventional manufacturing methodVSAvoidrigidity
Core Design Contradiction:
Ease of manufactureVSStrength

Solution Approach 1:

The patent merges multiple metal elements (leaf, door pillars, crosspieces, stretchers) into a single integrated structural element made from one piece of composite material. This eliminates the need for fixing elements like rivets, bolts, or welds that would compromise rigidity, while maintaining ease of manufacture through composite material forming processes.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent replaces traditional metal materials with composite materials (such as fiber-reinforced polymers) that provide equivalent or superior mechanical properties including rigidity and strength, while enabling monolithic construction without assembly fasteners.

Inventive Principle:
Principle #40Composite materials

2Strength

If reinforcing elements are added to increase rigidity, then the rigidity of the structural element is improved, but the number of parts increases further

Engineering Contradiction:
ImproverigidityVSAvoidnumber of parts
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The patent integrates reinforcing functions directly into the monolithic composite structure through strategic material distribution and structural design (such as varying fiber orientation, density, or layering within the composite) rather than adding separate reinforcing elements, thus maintaining uniform rigidity without increasing part count.

Inventive Principle:
Principle #5Merging (Combining)

3Strength

If metal materials are used for structural elements, then the structural element has sufficient strength, but the mass of the structural element increases

Engineering Contradiction:
ImprovestrengthVSAvoidmass
Core Design Contradiction:
StrengthVSWeight of moving object

Solution Approach 1:

The patent employs composite materials (such as carbon fiber reinforced polymers or glass fiber reinforced polymers) that offer high strength-to-weight ratios, providing equivalent or superior strength compared to metal while significantly reducing the mass of the structural element.

Inventive Principle:
Principle #40Composite materials

4Ease of manufacture

If fixing elements are used to assemble elements, then the structural element can be constructed from multiple parts, but the appearance is degraded due to visible fasteners

Engineering Contradiction:
Improveassembly capabilityVSAvoidappearance
Core Design Contradiction:
Ease of manufactureVSShape

Solution Approach 1:

The patent creates a monolithic composite structure that eliminates the need for visible fasteners or joint lines, providing a smooth, continuous surface that enhances aesthetic appearance while maintaining manufacturing efficiency through integral forming processes.

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 results in a structural element with uniform rigidity, reduced mass, and a satisfactory aesthetic appearance, as it simplifies production and integrates reinforcing elements within the composite material, enhancing mechanical properties while adhering to fire safety standards.

Implementation Method 1

each being formed of an envelope encasing a foam core

Methodology Applied
Scientific EffectBuoyancy: Archimedes' Principle (Buoyancy)

Implementation Method 2

the composite material is formed from a matrix of thermosetting material mixed with continuous fibres

Methodology Applied
Scientific EffectChemical Bonding: Chemical Bonding

Data Source

PatentEP2660119B1Method for producing a structural element of a railway vehicle
Publication Date: 2018.09.12 ALSTOM TRANSPORT TECH SAS
  • EP2660119B1 patent drawingFigure 1
  • EP2660119B1 patent drawingFigure 2~4
  • EP2660119B1 patent drawingFigure 5~7

AI summary

The element (1) has a beam (2) extending along longitudinal direction. A web (4) is extended perpendicularly to the longitudinal direction. The beam and the web are formed in a shell encasing a core (6) made of foam. The beam and a shell of the web are formed together as single piece for forming an envelope of the element. The envelope comprises a hollow profile made of a composite material extending in the longitudinal direction to form a case of the beam and in a direction perpendicular to the longitudinal direction to form the shell of the web.