Composite Railway Chassis Panel for 15-Minute Fire Resistance

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Solution Overview

Problem

Current railway vehicle chassis floor structures fail to maintain mechanical functions for at least 15 minutes during a fire, as they do not adequately withstand the thermal and structural stresses involved.

Innovation Solution

A composite panel chassis design featuring an upper metal layer, an intermediate metal layer with a balsa wood or bark core, and a lower metal layer with a cork-based core, secured to a frame with stops, where the metal layers are made of lacquered anodized aluminum and stainless steel respectively, and the cores are bonded with epoxy glue to ensure structural integrity and heat management.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a conventional composite panel is used in the chassis, then the structure is simple and easy to manufacture, but the mechanical functions cannot be maintained for at least 15 minutes in the event of a fire

Engineering Contradiction:
Improvefire resistance durationVSAvoidcomposite panel structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies composite materials by constructing a multi-layer panel consisting of metal layers (aluminum or steel) combined with wood or bark-based cores. This composite structure provides enhanced fire resistance for at least 15 minutes while maintaining mechanical strength, directly resolving the contradiction between reliability under fire conditions and structural complexity.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent implements the nesting principle by creating a sandwich structure where wood or bark cores are positioned between metal layers, with additional layers nested sequentially. This multi-layered configuration (metal-wood-metal-wood-metal) achieves superior fire performance without excessive complexity, as each layer serves a specific functional purpose.

Inventive Principle:
Principle #7Nested doll (Nesting)

2Reliability

If the lower metal layer is made of steel, then the fire resistance is improved, but the weight of the chassis increases

Engineering Contradiction:
Improvefire resistanceVSAvoidchassis weight
Core Design Contradiction:
ReliabilityVSWeight of moving object

Solution Approach 1:

The patent applies local quality by making only the lower metal layer (the side exposed to fire) from steel or stainless steel, while the upper metal layer remains aluminum or aluminum alloy. This localized use of steel provides the necessary fire resistance at the critical fire-exposed interface without increasing the overall weight significantly, as the upper layer maintains lighter material properties.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent utilizes parameter changes by selecting different steel grades (such as stainless steel) with varying properties to optimize the balance between fire resistance and weight. The specific choice of steel type and thickness allows achieving the 15-minute fire resistance requirement while minimizing weight increase.

Inventive Principle:
Principle #35Parameter changes

3Temperature

If the upper core of wood or bark has a thickness of between 20 millimeters and 100 millimeters, then the thermal insulation is improved, but the volume and weight of the panel increase

Engineering Contradiction:
Improvethermal insulationVSAvoidpanel volume
Core Design Contradiction:
TemperatureVSVolume of moving object

Solution Approach 1:

The patent applies parameter changes by optimizing the thickness of the wood or bark cores within the range of 20-100 mm based on specific fire resistance requirements. This parameter optimization achieves the necessary thermal insulation performance (maintaining temperature differentials for 15 minutes) while controlling panel volume and weight through selective thickness adjustment rather than uniform thickening.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent implements local quality by varying the thickness of wood or bark cores at different locations within the composite panel structure. Thicker cores are placed where greater thermal insulation is needed, while thinner sections are used where less insulation is required, thereby achieving overall thermal performance without maximizing volume and weight throughout the entire panel.

Inventive Principle:
Principle #3Local quality

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

The composite panel maintains mechanical strength and integrity for at least 15 minutes during a fire, preventing heat and smoke from reaching the interior and ensuring passenger safety by managing thermal energy and maintaining structural integrity under static loading conditions.

Implementation Method 1

the upper core of wood or bark has a density of between 50 g/cm3 and 250 g/cm3... the lower core made of wood or bark has a density of between 200 g/cm3 and 500 g/cm3

Methodology Applied
Scientific EffectThermal insulation: Thermal Insulation

Implementation Method 2

The different layers and cores of the composite panel 15 are held together by a polymer glue. Such a polymer glue is, for example, an epoxy glue sized to guarantee good adhesion between the different layers and ensure the mechanical strength of the composite panel 15

Methodology Applied
Scientific EffectAdhesion: Adhesive

Implementation Method 3

In the event of a fire under the chassis 10, the assembly 45 deteriorates and consumes part of the energy produced by the fire, which allows the assembly 40 to retain its integrity

Methodology Applied
Scientific EffectHeat absorption: Absorption (physical)

Data Source

PatentEP4382390A1Vehicle frame comprising a composite panel with fire-retardant function
Publication Date: 2024.06.12 ALSTOM HOLDINGS SA
  • EP4382390A1 patent drawingFigure 1
  • EP4382390A1 patent drawingFigure 2
  • EP4382390A1 patent drawing

AI summary

The present invention relates to a chassis for a vehicle, in particular a railway, comprising a composite panel (15) having: - an upper metal layer (25), - an intermediate metal layer (29), - an upper core of wood or bark-based material (27) disposed between the upper metal layer (25) and the intermediate metal layer (29), - a lower metal layer (33), - a lower core of wood or bark-based material (31) disposed between the intermediate metal layer (29) and the lower metal layer (33), the lower metal layer (33) comprising steel.