Railway sleeper with resilient sole for vibration attenuation
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Solution Overview
Problem
Current railway track systems with resilient sleepers and rails do not adequately attenuate mechanical vibrations, particularly in the frequency range up to 250 Hz, leading to nuisances in surrounding buildings and stress on the track system.
Innovation Solution
The crosspiece design features a resilient sole with dynamic stiffness between 6kN/mm and 10kN/mm, combined with resilient segments and a bearing element, and a mass distribution that includes a single block or two blocks with a transverse spacer, to enhance vibration attenuation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional resilient sleepers with rigid liners are used, then the track system provides structural support, but vibration attenuation performance is insufficient in the frequency range up to 250 Hz
Solution Approach 1:
The patent changes the dynamic stiffness parameter of the resilient sole from conventional high values to a specific range of 6-10 kN/mm. This parameter modification enables the system to achieve superior vibration attenuation in the 0-250 Hz frequency range while maintaining adequate structural support stability through the optimized stiffness value.
Solution Approach 2:
The patent employs composite material construction by combining a resilient sole with dynamic stiffness of 6-10 kN/mm, resilient segments with dynamic stiffness of 20-25 kN/mm, and a rigid liner. This composite structure achieves both effective vibration attenuation and reliable structural support through the synergistic properties of different materials.
2Strength
If the resilient sole has high dynamic stiffness, then structural support is improved, but vibration attenuation in the frequency range up to 250 Hz deteriorates
Solution Approach 1:
The patent optimizes the dynamic stiffness parameter of the resilient sole to a specific range of 6-10 kN/mm, which is lower than conventional high stiffness values. This parameter change enables the resilient sole to provide adequate structural support while simultaneously improving vibration attenuation performance in the 0-250 Hz frequency range.
Solution Approach 2:
The patent divides the resilient support system into multiple segments with different dynamic stiffness characteristics: the resilient sole (6-10 kN/mm) for vertical support and vibration attenuation, and resilient segments (20-25 kN/mm) for lateral support. This segmentation allows each component to be optimized for its specific function.
3Ease of manufacture
If conventional resilient support elements are used, then the track system is easier to manufacture, but vibration attenuation performance deteriorates compared to floating slab systems
Solution Approach 1:
The patent achieves vibration attenuation performance comparable to floating slab systems by optimizing the dynamic stiffness parameter of the resilient sole to 6-10 kN/mm. This parameter optimization enables the simpler sleeper structure to match the vibration attenuation performance of more complex floating slab systems while maintaining ease of manufacture.
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 design significantly improves vibration attenuation performance, lowering the cut-off frequency and insertion gain, thereby reducing mechanical stress and noise in the specified frequency range, comparable to floating slab systems.
Implementation Method 1
The resilient sole placed between the block and the rigid liner forms a second elastic stage. The vibrations generated by the rails as the trains pass are essentially damped at the level of the first and second elastic stages.
Implementation Method 2
Each rail generally rests on a resilient support element, placed between each rail and the rigid block. The resilient support elements thus form an elastic first stage.
Data Source
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AI summary
The sleeper (8) has a rigid concrete block (9) with a lower surface, and an upper face to receive a longitudinal rail (4), where the block has a weight ranging between 400 and 450 kilograms. A shoe (20) receives the rigid block, and is formed of a rigid shell comprising a peripheral edge (50) bordering a base of the shell. A resilient tie plate (22) is arranged between the lower surface of the block and the base of the shoe. The tie plate has a dynamic stiffness ranging from 6-8 kilo-newtons per millimeter.