Rail Active Damping via Piezoelectric Counter-Vibration
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Solution Overview
Problem
Current noise reduction systems for rail traffic are costly and ineffective in significantly attenuating acoustic vibrations, as they require full integration into railway carriages and do not adequately address the noise pollution issues in noise-sensitive areas.
Innovation Solution
A system comprising sensors and actuators integrated into the rail infrastructure to detect and counteract vertical and horizontal vibrations, using piezoelectric components and a control unit to generate counter-vibrations that destructively interfere with the noise-causing vibrations, thereby reducing noise emissions without the need for widespread carriage integration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If passive noise reduction systems (covers, attenuation underlays) are used, then some noise reduction is achieved, but the sound pressure level reduction is limited to up to 3 dB(A)
Solution Approach 1:
The patent replaces passive mechanical noise reduction systems (covers, attenuation underlays) with an active control system using piezoelectric actuators that generate counter-vibrations to cancel noise-causing vibrations, achieving significantly higher noise reduction effectiveness
Solution Approach 2:
The patent changes the approach from passive static noise reduction to active dynamic noise reduction by using piezoelectric actuators that can dynamically adjust their output based on detected vibration frequencies and amplitudes, enabling effective reduction of structure-borne noise
2Object-affected harmful factors
If active vibration control systems are integrated into each wheel of railway carriages, then wheel vibrations are reduced, but the cost and complexity increase significantly
Solution Approach 1:
The patent extracts the active vibration control system from the railway carriage and relocates it to the rail infrastructure itself, using piezoelectric actuators mounted on the rail to counteract vibrations at the source rather than requiring integration into each vehicle
Solution Approach 2:
Instead of controlling vibrations from the vehicle side (wheel-rail contact point), the patent inverts the approach by placing sensors and actuators on the rail to detect and counteract vibrations at their origin, eliminating the need for vehicle modifications
3Object-affected harmful factors
If all railway carriages are equipped with active vibration control systems, then effective noise reduction is achieved, but the costs become substantial
Solution Approach 1:
The patent removes the requirement for vehicle-specific active vibration control systems by relocating the control functionality to the rail infrastructure, eliminating the need to equip multiple carriages and significantly reducing overall system cost
4Reliability
If piezoelectric actuators are used for active damping, then low maintenance and high durability are achieved, but the ability to handle large vibration amplitudes is limited
Solution Approach 1:
The patent divides the active damping function into multiple piezoelectric actuators distributed along the rail, with each actuator handling a specific segment or frequency range, allowing the system to collectively manage large vibration amplitudes while maintaining the low-maintenance advantage of piezoelectric technology
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 solution effectively reduces noise emissions along specific rail sections, lowering costs and maintenance requirements, while maintaining the durability and low maintenance needs of piezoelectric actuators, and can be easily retrofitted into existing rail systems without disrupting maintenance operations.
Implementation Method 1
at least one piezoelectric actuator for exciting a counter-vibration of the rail
Data Source
AI summary
A system for actively attenuating acoustic vibrations of a rail for rail traffic is provided including at least one sensor for detecting at least a vertical acoustic vibration of the rail, at least one actuator for exciting at least a vertical counter-vibration of the rail and at least one control unit communicatively connected to the at least one sensor and the at least one actuator for controlling the at least one actuator depending on the vibration detected by the sensor, the counter-vibration being adapted to destructively interfere with the detected vibration, and the at least one actuator being mechanically coupled to the rail and to a carrier element supporting the rail. Also provided is a carrier element for the system and a method for actively attenuating acoustic vibrations of a rail for rail traffic.