Horizontal Spring Vibration Absorber for Low-Frequency Bridge Flutter
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing tuned mass dampers are ineffective for controlling low-frequency vortex-induced vibrations in long-span bridges due to their large size, high cost, and limited applicability, particularly for frequencies below 0.2 Hz, which restricts their use to higher frequency vibrations.
Innovation Solution
A semi-active vibration absorption and energy dissipation control system with a horizontally placed spring, using fiber-reinforced nylon materials and coaxial pulleys, allows for adjustable stiffness and mass, reducing costs and weight, and enabling control of low-frequency vibrations by placing the device at the bottom of the beam with a compact design that can be easily assembled and disassembled.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional tuned mass damper is used to control bridge vibration, then vibration control effectiveness is improved, but device weight and cost increase significantly
Solution Approach 1:
The patent changes the spring orientation from vertical to horizontal placement, which fundamentally alters the gravitational effects on the system. This parameter change allows the mass to be reduced by over 50% while maintaining vibration control effectiveness, as the horizontal configuration eliminates the need for the mass to counteract gravity in the vertical direction
Solution Approach 2:
The patent introduces adjustable damping coefficients and stiffness parameters that can be dynamically tuned to match different bridge vibration characteristics. This dynamic adjustability allows the system to maintain high control effectiveness with less mass, as the parameters can be optimized for specific vibration modes and frequencies
2Reliability
If a traditional tuned mass damper is used to control bridge vibration, then vibration control effectiveness is improved, but engineering cost increases by one to two orders of magnitude
Solution Approach 1:
The horizontal spring configuration and reduced mass requirements directly translate to lower material costs and simpler installation procedures. The patent reports cost reductions of one to two orders of magnitude compared to traditional TMDs with equivalent control effectiveness
Solution Approach 2:
The patent uses conventional, readily available materials such as steel springs, cables, and dampers that can be manufactured at low cost. The simplified design allows for easier replacement and maintenance, further reducing lifecycle costs
3Reliability
If a traditional tuned mass damper is used, then high-frequency vibration control is achieved, but applicability to low-frequency vibrations below 0.2 Hz is limited
Solution Approach 1:
The horizontal spring configuration changes the gravitational influence on the system dynamics, allowing the mass-spring-damper system to effectively control lower frequencies. The adjustable damping and stiffness parameters enable tuning across a wide frequency range from below 0.2 Hz to higher frequencies, vastly improving adaptability
Solution Approach 2:
The patent designs a universal vibration control system that can handle both low-frequency vortex-induced vibrations and high-frequency vibrations through parameter adjustment. The same basic configuration serves multiple frequency ranges and vibration modes, enhancing versatility
4Volume of moving object
If the spring is placed vertically inside the box beam, then space utilization is improved, but spring length is limited and vibration frequency adjustment range is restricted
Solution Approach 1:
The patent transitions the spring from vertical to horizontal placement, utilizing the horizontal dimension instead of the vertical space inside the box beam. This dimensional change removes the space constraints that limited spring length and frequency adjustment range, allowing for longer springs and wider frequency tuning
5Reliability
If high mass is used in the vibration control system, then control efficiency is improved, but device weight increases and cost increases
Solution Approach 1:
The horizontal spring configuration and optimized damping parameters allow the system to achieve high control efficiency with reduced mass. The parameter optimization ensures that the lighter mass body can still effectively counteract bridge vibrations through proper tuning of stiffness and damping
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 system effectively controls vortex-induced vibrations and flutter across a wide frequency range, significantly reducing engineering costs and improving control efficiency, with the ability to adjust parameters for optimal performance, including the use of a water bag for mass body, enhancing the system's applicability and competitiveness.
Implementation Method 1
a linear tensile spring 2 connected in series or in parallel
Implementation Method 2
the parameters of the rigidity of the linear tensile spring 2, the diameters of the first pulley 7 and the second pulley 8, and the mass of the mass body 10 are designed so that the vibration frequency of the vibration control system is basically consistent with the controlled vortex-induced vibration frequency of the bridge
Implementation Method 3
By using two coaxial pulleys with different diameters, the vibration of the mass body can be amplified
Implementation Method 4
The energy dissipation device 12 is connected with the electric control jack 13, and controlled by movement and states
Data Source
AI summary
The present invention provides a semi-active vibration absorption and energy dissipation control system for restraining vortex-induced vibration of bridges. It has the advantages and characteristics that: (1) springs are horizontally placed at the bottom of a beam, and lengths are not limited, so that the frequency requirement of a low-frequency target can be satisfied; (2) different target frequencies can be realized through different combinations of a plurality of springs connected in series and in parallel, so that multi-order vortex-induced vibration control needs are satisfied; (3) the springs made of fiber reinforced nylon materials are adopted, and are notched, so that a frequency implementation range can be greatly widened; (4) the material and the form of a mass body are not limited, and a water bag can be used, which has low cost and is convenient for disassembly, assembly and mass adjustment.