Adjustable Torsional-Vertical Vibration Wind Tunnel Testing Device
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Solution Overview
Problem
Existing wind tunnel testing devices for bridge models face difficulties in efficiently adjusting the torsional-vertical frequency ratio for large-amplitude coupled free vibration tests, as they require cumbersome hub modifications and incur high costs due to the need for hubs of different sizes, which can lead to system overload.
Innovation Solution
A torsional-vertical coupled free vibration wind tunnel testing device utilizing lightweight rigid rods, circular hubs, thin strings, linear tensile springs, and carbon fiber ropes, where the diameter of small hubs and the number, diameter, and length of carbon fiber ropes can be adjusted to achieve various torsional-vertical vibration frequency ratios, providing adjustable torsional stiffness and vertical deformation without tilt.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If hubs with different diameters are used to adjust torsional stiffness and frequency ratio, then the torsional-vertical vibration frequency ratio can be adjusted, but the testing work becomes cumbersome and the cost increases
Solution Approach 1:
The patent changes the physical parameters of the existing hubs (diameter, wall thickness) and the carbon fiber strings (number, diameter, length, winding layers) to adjust torsional stiffness and frequency ratio, rather than replacing entire hubs. This allows continuous adjustment of the frequency ratio while keeping the basic hub structure unchanged, significantly reducing testing complexity and cost
Solution Approach 2:
The patent introduces adjustable parameters (carbon fiber string configuration, hub dimensions) that allow the system to dynamically adapt to different testing requirements. By modifying these parameters, the same basic structure can achieve different torsional stiffness values and frequency ratios, making the system versatile without increasing complexity
2Adaptability or versatility
If hubs with very large diameters are used to achieve desired frequency ratios, then the frequency ratio adjustment is possible, but the system may become overloaded and unfeasible
Solution Approach 1:
Instead of increasing hub diameter to adjust frequency ratio, the patent changes other parameters: the number and diameter of carbon fiber strings, their length, and winding layers. This allows achieving the desired frequency ratio without overloading the system, as these parameters can be adjusted independently of the hub's structural load-bearing capacity
Solution Approach 2:
The patent segments the torsional stiffness adjustment function into multiple independent elements (multiple carbon fiber strings with adjustable diameter, number, and length) rather than relying on a single hub dimension. This allows fine-tuning of the frequency ratio while distributing the load across multiple elements, preventing system overload
3Adaptability or versatility
If hubs of different sizes are manufactured to achieve various frequency ratios, then the frequency ratio adjustment is possible, but the cost increases
Solution Approach 1:
The patent uses standard-sized hubs and achieves frequency ratio variation by changing parameters of cheaper components: carbon fiber string diameter, number of strings, string length, and winding layers. This approach is more cost-effective than manufacturing custom hubs of different sizes, as string parameters can be adjusted without expensive tooling or specialized manufacturing processes
Solution Approach 2:
The patent creates a dynamically adjustable system where the frequency ratio can be changed by modifying carbon fiber string configuration rather than manufacturing different hubs. This makes the system adaptable to different testing requirements while maintaining a single basic hub design, significantly reducing manufacturing costs
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 allows for quick and effective adjustment of torsional-vertical frequency ratios, enhancing the range of achievable frequency ratios and reducing the complexity and cost associated with hub modifications, while maintaining constant mass and stiffness during testing.
Implementation Method 1
The linear vertical and torsional stiffness of the system can be realized by the linear tensile stiffness of springs and rigid circular hubs
Implementation Method 2
The torsional stiffness can be achieved by adjusting the diameter of the small hubs and the tensile stiffness of the carbon fiber strings
Data Source
AI summary
The invention discloses a coupled free vibration wind tunnel testing device with adjustable frequency ratio of torsional-vertical vibration, belonging to the technical field of bridge wind tunnel testing device. The device includes rigid testing model, lightweight rigid rods, lightweight rigid circular hubs, thin strings, linear tensile springs, carbon fiber ropes, and lightweight small hubs. The invention adjusts the torsional stiffness of the system by conveniently changing the diameter of the small hub, the diameter and length of the carbon fiber rope, etc. The device has the advantages of simple structure, convenient installation and avoiding the previous tedious work. It can achieve a variety of torsional-vertical vibration frequency ratio testing conditions by using only one diameter large hub. It can not only greatly save the time of replacing the large hub, but also facilitate the realization of higher torsional-vertical vibration frequency ratio testing conditions which are difficult to achieve by the previous methods.