Method and System for Rapid Determination of Hydroelastic Model Test Conditions of Large Ships

Abstract

The present invention relates to a method and system for quickly determining the test conditions of a large ship hydroelasticity model. It includes: providing the environment for the ship hydroelasticity model test and determining the vertical first-order vibration wet modal frequency f of the model ship hull girder in the current test running state of the provided ship hydroelasticity model test environment v1 ; based on the current test running state of the hydroelastic test ship and the vertical first-order vibration wet modal frequency f determined in the current test running state v1 , configuring the wave circular frequency ω in the ship hydroelastic test environment o so that obvious hydroelastic responses are generated by the hydroelastic test ship at the configured wave circular frequency ω o . The present invention can quickly and accurately give the test conditions of the wave-excited vibration hydroelasticity model test in regular waves, improving the test efficiency.

Description

Technical Field

[0001] The present invention relates to a determination method and system, in particular to a method and system for quickly determining the test conditions of a large ship hydroelastic model test. Background Art

[0002] Currently, due to the gradual enlargement and high-speed development of ships, and at the same time, due to the use of high-strength steel, the stiffness of the hull is reduced and the flexibility is increased, and the wave encounter frequency is getting closer and closer to the hull wet modal vibration frequency. When the wave encounter frequency is equal to the hull wet modal vibration frequency, the frequency of the first-order exciting force is equal to the hull wet modal vibration frequency, and the ship will undergo linear wave-induced vibration.

[0003] The vertical bending moment of the hull caused by wave-induced vibration can even reach more than one-half of the wave bending moment, resulting in relatively serious hull structural fatigue problems. When the ship size is larger, the wave-induced vibration phenomenon may be more serious.

[0004] One of the research methods for wave-induced vibration is to conduct a tank model test. At present, there is no clear method for determining the test conditions of the tank model test. Although the wet modal frequency of the wave load test ship model can be calculated in advance through corresponding programs and software, due to calculation errors and other reasons, there is a certain error between the calculated result and the measured result of the test.

[0005] In addition, the wave frequency bandwidth that causes the wave-induced vibration phenomenon of the ship is particularly small. If the wave frequency changes slightly, it may be impossible to capture the obvious wave-induced vibration phenomenon in the regular wave test. To solve this problem, the resonance phenomenon can be captured by constantly changing the wave frequency, but this method leads to low test efficiency and even increases the risk of test failure. Summary of the Invention

[0006] The object of the present invention is to overcome the deficiencies existing in the prior art, and provide a method and system for quickly determining the test conditions of a large ship hydroelastic model test, which can quickly and accurately give the test conditions of the wave-induced vibration hydroelastic model test in regular waves and improve the test efficiency.

[0007] According to the technical solution provided by the present invention, a method for quickly determining the test conditions of a large ship hydroelastic model test, the test condition determination method includes:

[0008] Providing the environment of the ship hydroelastic model test, and determining the vertical first-order vibration wet modal frequency f of the model ship hull girder of the hydroelastic test ship in the current test running state v1 ;

[0009] Based on the current test running state of the hydroelastic test ship and the vertical first-order vibration wet modal frequency f determined in the current test running statev1 Configure the wave circular frequency ω in the ship hydroelastic test environment o so that under the configured wave circular frequency ω o the hydroelastic test ship generates obvious hydroelastic responses.

[0010] Determine the vertical first-order vibration wet mode frequency f of the hull girder of the hydroelastic test ship model, including: v1 when, including:

[0011] Drive the hydroelastic test ship to vibrate in the pool of the provided ship hydroelastic model test environment;

[0012] After the hydroelastic test ship vibrates in the pool, obtain the midship section bending moment decay curve, and process the obtained midship section bending moment decay curve to obtain the vertical first-order vibration wet mode frequency f of the hull girder of the ship model. v1 .

[0013] When obtaining the midship section bending moment decay curve, measure and record the vibration state of the hull midship section bending moment of the hydroelastic test ship, so as to generate the midship section bending moment decay curve based on the measured and recorded vibration state of the hull midship section bending moment;

[0014] When processing the midship section bending moment decay curve, it includes performing Fourier transform on the midship section bending moment decay curve to generate a response frequency distribution spectrogram. After generating the response frequency distribution spectrogram, configure the abscissa corresponding to the first peak as the vertical first-order vibration wet mode frequency f of the hull girder of the ship model. v1 .

[0015] Configure the wave circular frequency ω in the ship hydroelastic test environment o when, then there is:

[0016]

[0017] where n is a real number, U is the speed of the hydroelastic test ship, β is the wave direction angle, and g is the acceleration due to gravity.

[0018] When measuring and recording the vibration state of the hull midship section bending moment of the hydroelastic test ship, a circular tube measuring beam is set on the hydroelastic test ship, where

[0019] Two strain sensors for monitoring the vibration state are set on the circular tube measuring beam, and the strain sensors are connected to the control device through a data acquisition instrument;

[0020] Use the control device to process to obtain the midship section bending moment decay curve, and process the midship section bending moment decay curve to obtain the vertical first-order vibration wet mode frequency f of the hull girder of the ship model. v1 .

[0021] When configuring the wave circular frequency ω oAfter that, it further includes verifying the state of the hydroelastic response generated by the hydroelastic test ship, where

[0022] During the verification, determine the number of wave peaks on the frequency distribution spectrum of the response. When there is only one wave peak on the frequency distribution spectrum of the response, the hydroelastic test ship does not currently generate a hydroelastic response; when there are two peaks on the frequency distribution spectrum of the response, the hydroelastic test ship currently generates a hydroelastic response.

[0023] A system for quickly determining the test conditions of a large ship hydroelastic model test includes a wet mode frequency acquisition unit and a wave circular frequency configuration unit. Among them, use the wet mode frequency acquisition unit to obtain the wet mode frequency f of the first-order vertical vibration of the ship model hull girder v1 , and use the wave circular frequency configuration unit to configure the wave circular frequency ω in the hydroelastic test environment of the ship o ;

[0024] The wet mode frequency acquisition unit and the wave circular frequency configuration unit quickly determine the test conditions based on the above-mentioned method.

[0025] Advantages of the present invention: Based on the current test operation state of the hydroelastic test ship and the wet mode frequency f of the first-order vertical vibration of the ship model hull girder determined under the current test operation state v1 , configure the wave circular frequency ω in the hydroelastic test environment of the ship o , so that under the configured wave circular frequency ω o , the hydroelastic test ship generates an obvious hydroelastic response, and can quickly and accurately give the test conditions of the wave-excited vibration hydroelastic model test in regular waves, improving the test efficiency. Description of the Drawings

[0026] Figure 1 is a flowchart for determining the test conditions of the present invention.

[0027] Figure 2 is a schematic diagram of an embodiment of the midship section bending moment decay curve of the present invention.

[0028] Figure 3 is a schematic diagram of an embodiment of the response frequency distribution spectrum of the present invention.

[0029] Figure 4 is a system block diagram of an embodiment of the present invention.

[0030] Figure 5 is a waveform diagram of an embodiment of the present invention recording the pool wave Wave and the time-domain curve Mv of the midship section bending moment when no hydroelastic response occurs.

[0031] Figure 6 is Figure 5Schematic diagram of an embodiment of the frequency distribution spectrogram after medium-frequency spectrum analysis.

[0032] Figure 7 This is a waveform diagram of an embodiment of the present invention for recording the pool wave Wave and the time-domain curve Mv of the midship section bending moment when the hydroelastic response occurs.

[0033] Figure 8 For Figure 7 Schematic diagram of an embodiment of the frequency distribution spectrogram after medium-frequency spectrum analysis. Detailed implementation manners

[0034] The present invention will be further described below in conjunction with specific drawings and embodiments.

[0035] In order to quickly and accurately give the test conditions of the wave-excited vibration hydroelastic model test of a regular wave and a method for quickly determining the test conditions of the hydroelastic model test of a large ship, in an embodiment of the present invention, the test condition determination method includes:

[0036] Provide the environment for the hydroelastic model test of the ship, and determine the vertical first-order vibration wet mode frequency f of the ship model hull girder in the current test running state of the hydroelastic test ship in the provided hydroelastic model test environment of the ship v1 ;

[0037] Based on the current test running state of the hydroelastic test ship and the vertical first-order vibration wet mode frequency f determined in the current test running state v1 , configure the wave circular frequency ω in the hydroelastic test environment of the ship o , so that under the configured wave circular frequency ω o , the hydroelastic test ship generates an obvious hydroelastic response.

[0038] For the hydroelastic model test of a large ship in a regular wave, it is the above-mentioned pool model test. Therefore, the environment of the hydroelastic model test of the large ship generally includes a pool adapted to the hydroelastic test ship, a wave maker for generating waves in the pool, a trailer for towing the hydroelastic test ship, etc. The specific situation of the hydroelastic model test environment of the large ship can be selected according to needs, as long as it can meet the required pool model test for the hydroelastic test ship. In the initial state, the hydroelastic test ship can float statically in the pool and be in a free state, preparing for the test of the hydroelastic test ship in waves with or without a speed. Generally speaking, large ships have relatively low stiffness and are more likely to have hydroelastic responses in waves. They can be considered as commonly used hydroelastic test ships. The specific situation of using large ships as hydroelastic test ships is consistent with the existing ones.

[0039] For the hydroelastic test ship, determine the vertical first-order vibration wet mode frequency f in the current test running state v1, i.e., the vertical first-order vibration wet modal frequency f of the hull girder of the ship model of the hydroelastic test ship v1 is directly related to the current test running state of the hydroelastic test ship.

[0040] Figure 1 A flowchart of an embodiment of the test condition determination method is shown in. For the hydroelastic model test, in one embodiment of the present invention, based on the current test running state of the hydroelastic test ship and the vertical first-order vibration wet modal frequency f of the hull girder of the ship model determined under the current test running state v1 After that, at this time, according to the current test running state of the hydroelastic test ship and the vertical first-order vibration wet modal frequency f of the hull girder of the ship model determined under the current test running state v1 , configure or determine the wave circular frequency ω of the waves generated in the water tank o , wherein, according to the configured wave circular frequency ω o , the hydroelastic test ship can generate obvious hydroelastic responses.

[0041] In one embodiment of the present invention, to determine the vertical first-order vibration wet modal frequency f of the hull girder of the ship model of the hydroelastic test ship v1 , it includes:

[0042] Drive the hydroelastic test ship to vibrate in the water tank of the provided ship hydroelastic model test environment;

[0043] After the hydroelastic test ship vibrates in the water tank, obtain the midship section bending moment decay curve, and process the obtained midship section bending moment decay curve to obtain the vertical first-order vibration wet modal frequency f of the hull girder of the ship model v1 .

[0044] As can be seen from the above description, in the initial state, the hydroelastic test ship is in a free state in the water tank, and the displacement of the hydroelastic test ship in the water tank is consistent with the rated displacement. Therefore, the existing common method can be used to drive the hydroelastic test ship to vibrate in the water tank. For example, the hydroelastic test ship can be struck with a hammer so that the hydroelastic test ship can vibrate freely in the water. Of course, other vibration methods for driving the hydroelastic test ship can also be used, which can be specifically selected according to needs, so as to meet the requirement of driving the hydroelastic test ship to vibrate in the water tank.

[0045] During the vibration of the hydroelastic test ship, obtain the midship section bending moment decay curve of the hydroelastic test ship, and process the obtained midship section bending moment decay curve so as to obtain the vertical first-order vibration wet modal frequency f of the hull girder of the ship model after processing v1 . In one embodiment of the present invention, during the process of obtaining the vertical first-order vibration wet modal frequency f of the hull girder of the ship model v1 , the hydroelastic test ship has no speed in the water tank.

[0046] In one embodiment of the present invention, when obtaining the midship section bending moment decay curve of the hydroelastic test ship, the vibration state of the midship section bending moment of the hydroelastic test ship is measured and recorded, so as to generate the midship section bending moment decay curve based on the measured and recorded vibration state of the midship section bending moment of the hull; wherein, the process of measuring and recording the vibration state of the midship section bending moment of the hydroelastic test ship includes:

[0047] For the hydroelastic test ship, at the midship section of the hydroelastic test ship, a 15 cm break is made as a sectional gap, and the hydroelastic test ship is divided into two sections. A circular tube measuring beam arranged from the bow to the stern is connected to the hydroelastic test ship to connect the two divided sections of the hydroelastic test ship into a whole. The sectional part is sealed and waterproofed with rubber skin, and the circular tube measuring beam is used to measure and record the sectional bending moment encountered on the hull section. At this time, the two ends of the circular tube measuring beam are respectively connected to the bow and stern of the hydroelastic test ship. The circular tube measuring beam can adopt the existing common form, and the cooperation mode of the circular tube measuring beam with the sectional hydroelastic test ship is the same as the existing one.

[0048] For the circular tube measuring beam, starting from satisfying the similarity of the dynamic characteristics of the structure, the circular tube measuring beam is regarded as a beam with both ends free. Based on the forced vibration differential equation of the circular tube measuring beam, it is made dimensionless to obtain the similarity criterion to be satisfied. When not considering the influences of shear, moment of inertia and damping of the circular tube measuring beam, and only considering the vertical bending, the forced vibration differential equation of the circular tube measuring beam can be obtained:

[0049]

[0050] Among them, taking the bow or stern of the hydroelastic test ship as the origin, the ship length as the x-axis, and the ship width as the y-axis to establish a coordinate system. In the above forced vibration equation, x is the abscissa of the circular tube measuring beam, and y is the ordinate of the circular tube measuring beam. E is the elastic modulus of the longitudinal structural steel of the hydroelastic test ship (unit: MPa); I(x) is the sectional moment of inertia of the hydroelastic test ship (unit: m 4 ); m(x) is the mass per unit length of the hydroelastic test ship (including the added mass) (unit: kg / m); p(x, t) is the external load distribution of the hydroelastic test ship subjected to waves (the force per unit length) (unit: N / m).

[0051] Let x = ξL, y = ηL and t = t′T θ , and divide by The dimensionless differential equation of forced vibration of the vertical bending of the floating body can be obtained:

[0052]

[0053] where L is the length of the hydroelastic test ship (unit: m); t is time (unit: s); T θ is the natural pitching period of the hydroelastic test ship (unit: s); T e is the wave encounter period (unit: s); ρ is the water density in the pool (unit: kg / m 3 ); K1 and K2 are dimensional coefficients; ξ, η, t′, and P′ are variables.

[0054] In the formula, that is, the between the full-scale ship and the hydroelastic test ship is equal; that is, the between the full-scale ship and the hydroelastic test ship is equal, which is ensured by the hydrodynamic similarity between the hydroelastic test ship and the full-scale ship. Therefore, the and between the full-scale ship and the hydroelastic test ship are equal, which is the decisive criterion for the fluid-structure dynamic similarity phenomenon during model load testing. The hydroelastic test ship is the model simulating the full-scale ship, and there is a one-to-one correspondence between the hydroelastic test ship and the full-scale ship, that is, it can effectively simulate the full-scale ship.

[0055] During the design of the hydroelastic test ship, the product EI(x) of the moment of inertia and the modulus of elasticity of the material of each cross-section along the ship length of the longitudinal total bending member of the hydroelastic test ship is reduced by the fifth power of the scale factor to ensure the similarity of the bending vibration frequency and vibration mode.

[0056] Secondly, on the circular tube measuring beam at the 15 cm segment gap of the mid-section of the hydroelastic test ship, two strain sensors are arranged. The two arranged strain sensors are longitudinally pasted along the axis of the circular tube measuring beam on the upper and lower surfaces at the middle position of the segment where the beam is located, and are used for measuring the mid-section bending moment Mv based on a half-bridge connection. Through a data acquisition instrument, it is connected to a control device to record in real time the bending moment vibration state of the mid-section of the hydroelastic test ship in still water after being struck.

[0057] The strain sensors can be vibration sensors or strain gauges, specifically depending on being able to obtain the bending moment vibration state of the mid-section of the hull of the hydroelastic test ship. Obtaining the bending moment vibration state of the mid-section of the hull of the hydroelastic test ship specifically includes the amplitude and interval of the vibration, etc.

[0058] Generally, the strain sensors for detecting vibration are connected to a control device such as a computer through a data acquisition instrument, and then the measurement and recording of the bending moment vibration state of the mid-section of the hull of the hydroelastic test ship can be achieved. Then, based on the measured and recorded bending moment vibration state of the mid-section of the hull, the control device generates a bending moment decay curve of the mid-section. Specifically, the method and process of generating the bending moment decay curve based on the bending moment vibration state of the mid-section of the hull can be the same as the existing ones, specifically depending on being able to obtain the bending moment decay curve.

[0059] After obtaining the midship section bending moment decay curve, it generally undergoes Fourier transform to generate a response frequency distribution spectrum diagram. Then, based on the generated response frequency distribution spectrum diagram, the first-order vertical vibration wet mode frequency f of the ship model hull girder can be obtained. v1 。

[0060] When processing the midship section bending moment decay curve (such as Figure 2 ), it includes performing Fourier transform (spectrum analysis) on the midship section bending moment decay time-domain curve to generate a response frequency distribution spectrum diagram (such as Figure 3 ). After generating the response frequency distribution spectrum diagram, the abscissa corresponding to the first peak will be read and configured as the first-order vertical vibration wet mode frequency f of the ship model hull girder v1 (the specific value of the corresponding abscissa, unit: Hz).

[0061] Of course, the first-order vertical vibration wet mode frequency f of the ship model hull girder can also be determined by other means v1 , and it can be specifically selected according to needs, so as to obtain the first-order vertical vibration wet mode frequency f of the ship model hull girder of the hydroelastic test ship in the current operating state v1 as the standard.

[0062] In an embodiment of the present invention, when configuring the wave circular frequency ω in the hydroelastic test environment of the ship o , there is:

[0063]

[0064] where n is a real number, U is the speed of the hydroelastic test ship, β is the wave direction angle, and g is the acceleration due to gravity.

[0065] In specific implementation, when a large ship is sailing in waves, there is the following relationship:

[0066] ω e = ω0 - k0Ucosβ

[0067] where ω e is the wave encounter frequency (unit: rad / s), ω o is the wave circular frequency (unit: rad / s). The wave circular frequency ω o is generally generated by the wave-making machine in the laboratory. The wave circular frequency ω o can generally be directly read and obtained, k0 is the wave number (unit: 1 / m), U is the speed of the hydroelastic test ship (unit: m / s); the speed U of the hydroelastic test ship can be directly read through the laboratory trailer, β is the wave direction angle (unit: degree); when running head-on into the waves, β = 180°, and g is the acceleration due to gravity (unit: m / s 2 ).

[0068] If a hydroelastic model test in regular waves is to be carried out, the first-order vertical vibration circular frequency ω of the hull girder v (unit: rad / s; ω v = 2πf v1 ) should be an integer multiple of the encounter wave frequency ω e , that is, ω e should be equal to ω v , 1 / 2ω v , 1 / 3ω v , 1 / 4ω v , 1 / 5ω v …… Only when this happens will an obvious hydroelastic response occur.

[0069] When the wave encounter frequency ω e is equal to the first-order vertical vibration circular frequency ω of the hull girder v , according to the above expression, that is, ω v = ω0 - k0Ucosβ. Since ω0 = 2πf0, then:

[0070]

[0071] In the formula: f0 is the wave frequency.

[0072] Therefore, according to the above expression, for the wave circular frequency ω o , there is:

[0073]

[0074] In specific implementation, according to the above expression, when different parameters n are set, different wave circular frequencies ω o can be obtained.

[0075] The above method specifies a method for quickly determining the hydroelastic test conditions of large ships in regular waves, that is, it can quickly and accurately give the wave frequencies corresponding to the wave-induced vibration hydroelastic model test conditions in regular waves.

[0076] In an embodiment of the present invention, after setting the wave circular frequency ω o , after generating waves using a wave maker, it is also necessary to verify whether the hydroelastic test ship has a hydroelastic response.

[0077] During the hydroelastic model test, record the wave Wave in the pool and the time-domain curve Mv of the midship section bending moment. Figure 5 The upper figure in it is the waveform diagram of the wave Wave in the pool when there is no hydroelastic response (the abscissa is time, and the ordinate is the wave height). Figure 5 The lower figure in it is the time-domain curve Mv of the midship section bending moment when there is no hydroelastic response (the abscissa is time, and the ordinate is the wave height).

[0078] For Figure 5 the wave in the middle pool (Wave) and the time-domain curve of the midship section bending moment (Mv), a spectral analysis is carried out to obtain a frequency distribution spectrogram. Figure 6 The upper figure inside shows the frequency distribution spectrogram of the wave in the pool (Wave). Figure 6 The lower figure inside shows the response frequency distribution spectrogram of the time-domain curve of the midship section bending moment (Mv). Figure 6 The abscissa inside is the frequency. Figure 6 In, when no hydroelastic response occurs, there is only one peak in the response frequency distribution spectrogram of the time-domain curve of the midship section bending moment (Mv).

[0079] During the hydroelastic model test, if a hydroelastic response occurs, Figure 7 a schematic diagram of an embodiment of the wave in the pool (Wave) and the time-domain curve of the midship section bending moment (Mv) shown in is provided. For Figure 7 the curves in, after spectral analysis, a frequency distribution spectrogram as shown in Figure 8 is obtained. It can be known from Figure 8 that when a hydroelastic response occurs, there are two peaks in the response frequency distribution spectrogram.

[0080] Therefore, during the hydroelastic model test, it is possible to determine whether a hydroelastic response has occurred based on the number of peaks in the response frequency distribution spectrogram, so as to achieve the purpose of verifying the test conditions at the current wave circular frequency ω o under the test conditions.

[0081] In summary, a system for quickly determining the test conditions of a large ship hydroelastic model can be obtained. In an embodiment of the present invention, it includes a wet mode frequency acquisition unit and a wave circular frequency configuration unit. Among them, the wet mode frequency acquisition unit is used to obtain the wet mode frequency f v1 of the first-order vertical vibration of the ship model hull girder, and the wave circular frequency configuration unit is used to set the wave circular frequency ω o in the hydroelastic test environment of the ship;

[0082] The wet mode frequency acquisition unit and the wave circular frequency configuration unit quickly determine the test conditions based on the method described above.

[0083] Specifically, the wet mode frequency acquisition unit includes a sensor and a control device as described above. The wave circular frequency configuration unit can use existing devices that can provide the wave circular frequency ω o . The wet mode frequency acquisition unit and the wave circular frequency configuration unit can adopt existing common forms. The method and process for the wet mode frequency acquisition unit and the wave circular frequency configuration unit to cooperate to determine the test conditions can refer to the above description.

Claims

1. A method for quickly determining the test conditions of a large ship hydroelasticity model, characterized in that The method for quickly determining the test conditions includes: Provide the environment for ship hydroelastic model tests and determine the vertical first-order vibration wet modal frequency of the hull girder of the hydroelastic test ship in the current test running state in the provided ship hydroelastic model test environment ; Based on the current test running state of the hydroelastic test ship and the vertical first-order vibration wet mode frequency of the ship model hull girder determined under the current test running state , configure the wave circular frequency in the ship hydroelastic test environment , so that under the configured wave circular frequency , the hydroelastic test ship generates obvious hydroelastic responses; Configure the wave circular frequency in the ship hydroelastic test environment Then, there is: wherein, is a real number, is the speed of the hydroelastic test ship, is the wave direction angle, is the acceleration of gravity.

2. The method for quickly determining the test conditions of the large ship hydroelasticity model according to claim 1, characterized in that, Determine the vertical first-order vibration wet mode frequency of the hull girder of the ship model for the hydroelasticity test when including: Driving the hydroelastic test ship to vibrate in the pool of the provided ship hydroelastic model test environment; After the hydroelastic test ship vibrates in the tank, obtain the midship section bending moment decay curve, and process the obtained midship section bending moment decay curve to obtain the first-order vertical vibration wet mode frequency of the ship model hull girder .

3. The method for quickly determining the test conditions of the large ship hydroelasticity model according to claim 2, characterized in that, When obtaining the midship section bending moment decay curve, measuring and recording the vibration state of the midship section bending moment of the hydroelastic test ship, so as to generate the midship section bending moment decay curve based on the measured and recorded vibration state of the midship section bending moment of the hull; When processing the midship section bending moment decay curve, it includes performing a Fourier transform on the midship section bending moment decay curve to generate a response frequency distribution spectrum diagram. After generating the response frequency distribution spectrum diagram, the abscissa corresponding to the first peak will be read and configured as the vertical first-order vibration wet mode frequency of the ship model hull girder. .

4. The rapid determination method for the test conditions of the large ship hydroelasticity model according to claim 2 or 3, characterized in that, When measuring and recording the vibration state of the midship section bending moment of the hydroelastic test ship, a circular tube measuring beam is arranged on the hydroelastic test ship, wherein, Two strain sensors for monitoring the vibration state are arranged on the circular tube measuring beam, and the strain sensors are connected to the control device through a data acquisition instrument; The control device is used to process and obtain the midship section bending moment decay curve, and the midship section bending moment decay curve is processed to obtain the wet natural frequency of the first vertical vibration mode of the ship model hull girder .

5. The rapid determination method for the operating conditions of the large ship hydroelasticity model test according to claim 2 or 3, characterized in that, in Configure the wave circular frequency After that, it also includes the state verification of the hydroelastic response generated by the hydroelastic test ship, where During calibration, determine the number of peaks on the response frequency distribution spectrogram. When there is only one peak on the response frequency distribution spectrogram, the hydroelastic test ship does not generate hydroelastic response currently; When there are two peaks on the response frequency distribution spectrogram, the hydroelastic test ship generates hydroelastic response currently.

6. A rapid determination system for the test conditions of a large ship hydroelasticity model, characterized in that, It includes a wet modal frequency acquisition unit and a wave circular frequency configuration unit. Among them, the wet modal frequency acquisition unit is used to obtain the wet modal frequency of the first-order vertical vibration of the hull girder of the ship model. The wave circular frequency configuration unit is used to configure the wave circular frequency in the ship hydroelastic test environment. ; The wet mode frequency acquisition unit and the wave circular frequency configuration unit quickly determine the test conditions based on the method described in any one of claims 1 to 5 above.

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