Rail Vehicle Sandwich Panel with Localized Sound Absorption

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Solution Overview

Problem

Existing sandwich panels in rail vehicle construction face a conflict between lightweight design and effective sound absorption, leading to increased costs due to uniform sound insulation across the entire floor, which is unnecessary in areas away from sound sources.

Innovation Solution

A sandwich panel design with a corrugated or trapezoidal core layer and cover layers, where only cavities near sound sources are filled with sound-absorbing materials like granules or foam, allowing for localized and adaptive sound insulation without altering the panel's external dimensions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If sound-absorbing material is provided between the core layer and cover layer throughout the entire floor, then sound absorption capacity is improved, but floor thickness increases and production costs increase

Engineering Contradiction:

Improvesound absorption capacityVSAvoidfloor thickness

Core Design Contradiction:

Object-affected harmful factorsVSVolume of moving object

Solution Approach 1:

The patent applies local quality by providing sound-absorbing material only in specific cavities of the honeycomb core structure rather than uniformly throughout the entire floor panel. This allows sound absorption to be concentrated in areas where it is most needed (above sound sources like bogies and drive motors) while maintaining thin floor thickness in areas where sound insulation is less critical.

Inventive Principle:

Principle #3Local quality

2Object-affected harmful factors

If sound-absorbing material is provided throughout the entire floor surface, then sound insulation is improved, but material costs and production costs increase

Engineering Contradiction:

Improvesound insulationVSAvoidmaterial usage

Core Design Contradiction:

Object-affected harmful factorsVSQuantity of substance

Solution Approach 1:

The invention implements local quality by selectively filling only certain cavities of the honeycomb structure with sound-absorbing material. This targeted approach ensures that sound insulation is provided precisely where sound sources are located (above bogies, drive motors, etc.) while avoiding unnecessary material usage in areas without sound sources, thereby reducing both material costs and production costs.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent applies partial action by providing sound insulation only to the extent necessary for effective noise control. Rather than insulating the entire floor surface, the invention fills only the cavities that will be positioned above sound sources during installation, achieving adequate sound insulation with minimal material quantity.

Inventive Principle:

Principle #16Partial or excessive action

3Object-affected harmful factors

If different thicknesses are used for sound-insulating areas versus non-sound-insulating areas, then sound absorption is optimized, but floor levelness and production complexity worsen

Engineering Contradiction:

Improvesound absorption optimizationVSAvoidfloor production simplicity

Core Design Contradiction:

Object-affected harmful factorsVSEase of manufacture

Solution Approach 1:

The patent applies segmentation by dividing the floor panel into multiple discrete cavities within the honeycomb core structure. This allows individual cavities to be selectively filled with sound-absorbing material while leaving other cavities empty, thereby achieving variable sound absorption characteristics across different floor regions without creating actual thickness variations that would complicate manufacturing and floor installation.

Inventive Principle:

Principle #1Segmentation

4Weight of moving object

If lightweight panels without sound insulation are used, then weight is reduced and costs are lowered, but sound absorption capacity deteriorates

Engineering Contradiction:

Improvepanel weightVSAvoidsound absorption capacity

Core Design Contradiction:

Weight of moving objectVSObject-affected harmful factors

Solution Approach 1:

The invention resolves this contradiction by applying local quality through selective cavity filling. The honeycomb core structure provides a lightweight base, and sound-absorbing material is added only in specific cavities above sound sources. This maintains overall panel lightness while providing targeted sound absorption capacity where needed, avoiding the weight and cost penalty of universal sound insulation.

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

This approach provides effective sound insulation with minimal material usage and reduced costs by tailoring sound absorption to specific areas, maintaining structural integrity and flexibility while optimizing soundproofing properties.

Implementation Method 1

at least some of the cavities are filled with a sound-absorbing material

Methodology Applied

Scientific EffectSound absorption: Acoustic Absorption

Data Source

PatentEP2196308B1Sandwich plate with improved sound absorption

Publication Date: 2017.10.04 ALSTOM TRANSPORT TECH SAS

Figure 1a~1b
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AI summary

The plate has a covering layer (1), and a core layer (5) connected with the covering layer and comprising cavities (7.1, 7.2), which are separated from each other. A part of the cavities is filled with a sound-absorbing material e.g. polyurethane-based foam. Another covering layer (3) is connected with the core layer. Another core layer comprises cavities separated from each other, where a part of the cavities in the latter core layer is filled with the sound-absorbing material. The covering layers, the core layers and/or a separating layer are made of aluminum or steel.