CN-121997823-A - Model similar design method suitable for wave-underwater vibration table test

CN121997823ACN 121997823 ACN121997823 ACN 121997823ACN-121997823-A

Abstract

A model similar design method suitable for wave-underwater vibration table test. The method comprises the steps of determining a geometric similarity ratio of a reduced scale model, determining a structural density similarity ratio, a structural elastic modulus similarity ratio and a water density similarity ratio of the reduced scale model, determining a vertical geometric similarity ratio, determining an x-direction geometric similarity ratio under the action of horizontal earthquake, determining a horizontal y-direction geometric similarity ratio, determining an x-direction wavelength similarity ratio, determining a wave height similarity ratio and the like. The method has the advantages that the method is simple and practical, the model is simple and convenient to manufacture, and a feasible method can be provided for the similar design of the wave-underwater vibrating table test model under the action of earthquake-wave.

Inventors

CHEN YU
LI ZHONGXIAN
WU KUN
HUANG XIN
ZHANG HUISHEN

Assignees

天津大学
中国民航大学

Dates

Publication Date: 20260508
Application Date: 20260122

Claims (8)

1. The model similar design method suitable for the wave-underwater vibration table test is characterized by comprising the following steps in sequence: step one, according to the pool size and the parameters of the underwater vibrating table test equipment, combining the prototype structure size to determine the geometric similarity ratio lambda l of the reduced scale model; Selecting the material which is the same as the prototype structure and water as the material of the reduced scale model, and determining the structural density similarity ratio lambda ρ , the structural elastic modulus similarity ratio lambda E and the water density similarity ratio lambda ρw of the reduced scale model; Determining a vertical geometric similarity ratio lambda lz by utilizing the geometric similarity ratio lambda l of the reduced scale model obtained in the step one; Step four, taking the structural inertia force similarity ratio and the structural elastic force similarity ratio as constraint conditions, and determining an x-direction geometric similarity ratio lambda lx under the action of a horizontal earthquake based on the structural elastic modulus similarity ratio lambda E and the structural density similarity ratio lambda ρ which are obtained in the step two and the vertical geometric similarity ratio lambda lz which are obtained in the step three; fifthly, determining a horizontal y-direction geometric similarity ratio lambda ly based on the x-direction geometric similarity ratio lambda lx under the horizontal earthquake action obtained in the fourth step by taking the structural inertia force similarity ratio and the earthquake motion hydraulic similarity ratio as constraint conditions; Step six, determining the wavelength similarity ratio lambda L of the x direction by using a dispersion formula based on the vertical geometric similarity ratio lambda lz obtained in the step three, the x-direction geometric similarity ratio lambda lx obtained in the step four and the water depth and the wavelength in the prototype; And step seven, taking the structural inertia force similarity ratio and the wave force similarity ratio as constraint conditions, and determining the wave height similarity ratio lambda H based on the structural density similarity ratio lambda ρ and the water density similarity ratio lambda ρw obtained in the step two, the vertical geometric similarity ratio lambda lz obtained in the step three, the x-direction geometric similarity ratio lambda lx obtained in the step four, the horizontal y-direction geometric similarity ratio lambda ly obtained in the step five and the x-direction wavelength similarity ratio lambda L obtained in the step six.
2. The method for model similarity design for wave-underwater vibration table test according to claim 1, wherein in the first step, the geometric similarity ratio λ l =reduced model size/prototype structure size is determined by: The weight of the reduced scale model after being reduced according to the geometric similarity ratio lambda l cannot exceed the designed maximum weight which can be borne by the underwater vibration table test equipment, and the water depth after being reduced according to the geometric similarity ratio lambda l cannot exceed the designed water depth of the pool.
3. The method according to claim 1, wherein in the second step, the structure density similarity ratio λ ρ =the density of the scaled model structure/the density of the prototype structure, the structure elastic modulus similarity ratio λ E =the elastic modulus of the scaled model structure/the elastic modulus of the prototype structure, the water density similarity ratio λ ρw =the water density in the scaled test/the water density in the prototype, and the scaled model test is made of the same material as the prototype structure and the water, so that the structure density similarity ratio λ ρ =1, the structure elastic modulus similarity ratio λ E =1, and the water density similarity ratio λ ρw =1.
4. The method for model similarity design for wave-underwater vibration table test according to claim 1, wherein in the third step, the expression of the vertical geometric similarity ratio λ lz is: 。
5. The method for model similarity design for wave-underwater vibration table test according to claim 1, wherein in the fourth step, the method for determining the x-direction geometric similarity ratio lambda lx under the action of horizontal earthquake based on the structural elastic modulus similarity ratio lambda E and the structural density similarity ratio lambda ρ obtained in the second step and the vertical geometric similarity ratio lambda lz obtained in the third step by taking the structural inertia force similarity ratio and the structural elastic force similarity ratio as constraint conditions is as follows: Assuming that the structural inertia force similarity ratio is equal to the structural elastic force similarity ratio, the expression of the x-direction geometric similarity ratio lambda lx under the action of horizontal earthquake is as follows: ; Wherein lambda g is the gravity acceleration similarity ratio, and the value is 1.0.
6. The method for designing model similarity suitable for wave-underwater vibration table test according to claim 1, wherein in the fifth step, the method for determining the horizontal y-direction geometrical similarity ratio lambda ly based on the x-direction geometrical similarity ratio lambda lx under the horizontal earthquake action obtained in the fourth step by using the structural inertia force similarity ratio and the earthquake motion hydraulic similarity ratio as constraint conditions is as follows: assuming that the structural inertia force similarity ratio is equal to the seismic dynamic hydraulic similarity ratio, the expression of the horizontal y-direction geometric similarity ratio lambda ly is: 。
7. The method for model similarity design for wave-underwater vibration table test according to claim 1, wherein in the sixth step, the method for determining the x-direction wavelength similarity ratio λ L by using a dispersion formula based on the vertical geometry similarity ratio λ lz obtained in the third step, the x-direction geometry similarity ratio λ lx obtained in the fourth step and the water depth and wavelength in the prototype is as follows: The wavelength similarity ratio lambda L in the x-direction is obtained by solving the following equation: ; Where h is the depth of water in the prototype and L is the wavelength in the prototype.
8. The model similarity design method for the wave-underwater vibration table test according to claim 1, wherein in the seventh step, the method for determining the wave height similarity ratio λ H based on the structural density similarity ratio λ ρ and the water density similarity ratio λ ρw obtained in the second step, the vertical geometry similarity ratio λ lz obtained in the third step, the x-direction geometry similarity ratio λ lx obtained in the fourth step, the horizontal y-direction geometry similarity ratio λ ly obtained in the fifth step, and the x-direction wavelength similarity ratio λ T obtained in the sixth step is as follows: assuming that the structural inertia force similarity ratio is equal to the wave force similarity ratio, the expression of the wave height similarity ratio λ H is: ; Wherein R is the radius of the section of the prototype structure, half the length of the upstream surface is taken, , , And The first-order Bessel functions and the second-order Bessel functions are respectively.

Description

Model similar design method suitable for wave-underwater vibration table test Technical Field The invention belongs to the technical field of civil engineering, and particularly relates to a model similarity design method suitable for a wave-underwater vibration table test. Background Along with the promotion of the national ocean strong construction, large-scale engineering construction such as cross-sea bridge, offshore wind power and the like is more and more. The structure is huge and complex in size and faces the threat of earthquake and extreme sea wave disasters, so that special analysis and research are required to be carried out in structural design. The wave-underwater vibration table model test is a key test means for analyzing dynamic response of a structure under the action of earthquake-waves. Reasonable model similarity design is a core step of developing a reduced scale model test, and is used for ensuring that the reduced scale model can reproduce the dynamic response of a prototype structure. In the wave-underwater vibration table model test, two medium materials of water and structure exist, and the premise of ensuring that the design of the water-structure scale model is reasonable is to keep the density similarity ratio of the two materials consistent. Since the density of water cannot be changed in the test, resulting in a density-like ratio of 1.0, the density-like ratio of the design structure should also be 1.0. However, in the conventional bench test model similarity design, in order to ensure that the scaled model has similar dynamic response to the prototype structure, additional mass is required to change the structure density, but adopting this design method may result in inconsistent density similarity ratio of the structure and water, and distort the water-structure interaction test. Thus, there are difficulties with the current model-like designs for wave-underwater shaker tests. Disclosure of Invention In order to solve the problems, the invention aims to provide a model similar design method suitable for a wave-underwater vibration table test, and the reduced scale model manufactured by the method has high dynamic response precision and is simple and convenient to manufacture. In order to achieve the above object, the method for designing a model similarity suitable for a wave-underwater vibration table test according to the present invention comprises the following steps performed in order: step one, according to the pool size and the parameters of the underwater vibrating table test equipment, combining the prototype structure size to determine the geometric similarity ratio lambda l of the reduced scale model; Selecting the material which is the same as the prototype structure and water as the material of the reduced scale model, and determining the structural density similarity ratio lambda ρ, the structural elastic modulus similarity ratio lambda E and the water density similarity ratio lambda ρw of the reduced scale model; Determining a vertical geometric similarity ratio lambda lz by utilizing the geometric similarity ratio lambda l of the reduced scale model obtained in the step one; Step four, taking the structural inertia force similarity ratio and the structural elastic force similarity ratio as constraint conditions, and determining an x-direction geometric similarity ratio lambda lx under the action of a horizontal earthquake based on the structural elastic modulus similarity ratio lambda E and the structural density similarity ratio lambda ρ which are obtained in the step two and the vertical geometric similarity ratio lambda lz which are obtained in the step three; fifthly, determining a horizontal y-direction geometric similarity ratio lambda ly based on the x-direction geometric similarity ratio lambda lx under the horizontal earthquake action obtained in the fourth step by taking the structural inertia force similarity ratio and the earthquake motion hydraulic similarity ratio as constraint conditions; Step six, determining the wavelength similarity ratio lambda L of the x direction by using a dispersion formula based on the vertical geometric similarity ratio lambda lz obtained in the step three, the x-direction geometric similarity ratio lambda lx obtained in the step four and the water depth and the wavelength in the prototype; And step seven, taking the structural inertia force similarity ratio and the wave force similarity ratio as constraint conditions, and determining the wave height similarity ratio lambda H based on the structural density similarity ratio lambda ρ and the water density similarity ratio lambda ρw obtained in the step two, the vertical geometric similarity ratio lambda lz obtained in the step three, the x-direction geometric similarity ratio lambda lx obtained in the step four, the horizontal y-direction geometric similarity ratio lambda ly obtained in the step five and the x-direction wavelength similarity ratio lambda L obtained