Under Sleeper Pad Elastomer Density for Track Stability
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Solution Overview
Problem
Railroad sleepers on ballast beds experience low transverse displacement resistance due to thermal fluctuations and weather changes, leading to track distortion and safety risks, especially in newly laid tracks, as the contact surface area between the sleeper and ballast is small.
Innovation Solution
An under sleeper pad with an elastomer layer of specific density (250-350 kg/m3) and properties, including tear resistance, elongation at break, and Shore A hardness, is used to enhance transverse displacement resistance by providing both plastic and elastic properties, allowing for effective ballast penetration and vibration damping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the contact surface area between the railroad sleeper and ballast is increased, then the transverse displacement resistance is improved, but the device complexity increases due to the need for additional fastening layers and structural components
Solution Approach 1:
The patent applies parameter changes by optimizing the density of the elastomer layer to a specific range (250-350 kg/m³) to achieve the desired balance between transverse displacement resistance and structural simplicity. This parameter optimization allows the under sleeper pad to provide sufficient stability without requiring complex fastening mechanisms.
Solution Approach 2:
The patent uses composite materials by combining the elastomer layer with appropriate fastening layers to create an under sleeper pad that achieves high transverse displacement resistance. The composite structure integrates the elastic properties of the elastomer with the fastening capability of the additional layers, providing both stability and ease of installation.
2Reliability
If the elastomer layer density is increased to improve transverse displacement resistance, then the stability is improved, but the vibration damping capability deteriorates
Solution Approach 1:
The patent resolves this contradiction by precisely controlling the density parameter of the elastomer layer within the range of 250-350 kg/m³. This parameter optimization ensures that the elastomer layer provides sufficient transverse displacement resistance while maintaining adequate vibration damping capabilities, avoiding the excessive density that would harm vibration damping.
Solution Approach 2:
The patent applies local quality by ensuring that the elastomer layer has specific local properties (density, tear resistance, elongation at break) that are optimized for both transverse displacement resistance and vibration damping. The fastening layer is also designed with specific local properties to complement the elastomer layer, creating a coordinated system that achieves both stability and vibration damping.
3Object-affected harmful factors
If the elastomer layer is made more elastic to improve vibration damping, then the vibration damping is improved, but the transverse displacement resistance deteriorates
Solution Approach 1:
The patent resolves this contradiction by optimizing the density parameter of the elastomer layer to a specific range (250-350 kg/m³) that balances elasticity and transverse displacement resistance. This parameter control ensures that the elastomer layer is sufficiently elastic for vibration damping while maintaining the density required for transverse displacement resistance.
Solution Approach 2:
The patent uses composite materials by combining the elastomer layer with fastening layers to create a system that achieves both vibration damping and transverse displacement resistance. The composite structure allows the elastomer layer to provide vibration damping while the fastening layer contributes to transverse displacement resistance, achieving a balance between the two functions.
4Reliability
If the under sleeper pad is designed with high transverse displacement resistance to prevent track distortion, then the track stability is improved, but the ease of installation deteriorates due to the need for complex fastening mechanisms
Solution Approach 1:
The patent applies parameter changes by optimizing the density of the elastomer layer to a specific range (250-350 kg/m³) that provides sufficient transverse displacement resistance without requiring complex fastening mechanisms. This parameter optimization allows the under sleeper pad to achieve track stability while maintaining ease of installation through simpler fastening designs.
Solution Approach 2:
The patent uses composite materials by combining the elastomer layer with appropriate fastening layers to create an under sleeper pad that achieves high transverse displacement resistance. The composite structure integrates the elastic properties of the elastomer with the fastening capability of the additional layers, providing both stability and ease of installation.
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 under sleeper pad achieves high transverse displacement resistance and improved track stability by maintaining ballast penetration and vibration damping, significantly increasing the positional stability of the track.
Implementation Method 1
the under sleeper pad also comprises an elastomer layer, which provides the under sleeper pad with corresponding elastic properties
Implementation Method 2
allowing for effective ballast penetration and vibration damping
Implementation Method 3
In order to give the elastomer layer sufficient strength, it is expediently provided that the elastomer layer has a tear resistance of 2.2 N/mm2 (newtons per square millimeter) to 4.0 N/mm2, preferably of 2.2 N/mm2 to 2.8 N/mm2
Data Source
AI summary
An under sleeper pad (1) for fastening to an outer surface (2) facing a ballast bed (16), in particular an underside, of a railroad sleeper (3). The under sleeper pad (1) includes an elastomer layer (5), the elastomer layer (5) having a density in the range of 250 kg/m3 to 350 kg/m3, preferably 250 kg/m3 to 330 kg/m3.