Icebreaker impact vibration noise test method and application

Abstract

The invention discloses a vibration noise testing method for icebreaking impact of an icebreaker and application, belongs to vibration noise testing, and particularly relates to vibration noise testing for icebreaking impact of the icebreaker. The problems that according to an existing electrical testing method, testing time is long, a proper testing frequency range is difficult to determine, and the accuracy is greatly affected by the environment are solved. The invention relates to a vibration noise test method for icebreaking impact of an icebreaker. The method comprises the following steps: acquiring vibration response data and noise response data of the icebreaker under an icebreaking-free working condition and an icebreaking working condition obtained in an icebreaking test; according to the icebreaking test, the test frequency and the monitoring points are determined by adopting the method for determining the monitoring points for icebreaking impact of the icebreaker. The vibration noise testing method for the icebreaking impact of the icebreaker and the application are suitable for quantitative evaluation of vibration response and noise response caused by the icebreaking impact of the icebreaker.

Description

Technical Field

[0001] The invention relates to a vibration noise test, in particular to a vibration noise test of an icebreaker's icebreaking impact. Background Art

[0002] When a ship sails in an ice area, it will inevitably collide with the surrounding floating ice. The ice-induced vibration between the floating ice and the ship will cause the vibration response and noise response of the hull structure.

[0003] Timely detection and evaluation of the vibration response and noise response of icebreakers under icebreaking impact will help to discover and solve potential safety hazards and improve the safety of icebreakers. It is also of great significance to improve the design and performance of icebreakers and improve icebreaking efficiency and effectiveness. Therefore, in order to measure the impact of ice-induced vibration, it is necessary to test and measure the vibration response and noise response.

[0004] For the test of noise response, the vibration noise test system combined with the sound pressure level measurement method is currently commonly used for testing, and the sound pressure, sound intensity, sound power and other parameters of the test equipment are tested in a point-by-point manner.

[0005] The vibration response test is differentiated according to the physical properties involved in the test process. Currently, it mainly includes mechanical measurement method, optical measurement method and electrical measurement method:

[0006] (1) Mechanical measurement method, that is, testing the mechanical vibration (such as displacement, acceleration, velocity) and system characteristic parameters (such as natural frequency, damping, vibration mode, etc.) through experimental methods. Because the energy loss of the mechanical structure is relatively large, the frequency range that can be measured will be smaller. Therefore, in the ship vibration acceleration detection, the accuracy of the vibration measurement results using the mechanical measurement method is relatively low, there are certain defects, and its application has limitations.

[0007] (2) Optical measurement method: The vibration parameters are converted into light signals, which are then amplified by an optical system and converted into electrical signals by a light detector. The technicians then measure and analyze the electrical signals to obtain the required vibration test results.

[0008] (3) The electrical measurement method is to convert the vibration parameters of components (such as displacement, velocity, acceleration) into electrical signals (such as current, voltage, etc.), which are then amplified by electronic systems. The electrical signal value and the vibration physical quantity value to be measured are then converted using a function to successfully complete the measurement and statistics.

[0009] The current application value of the electrical measurement method is more prominent than that of the mechanical measurement method and the optical measurement method. Its advantages are high measurement accuracy, good sensitivity and fast response speed; however, the electrical measurement method still has the following problems:

[0010] (1) The electrical test method takes a long time;

[0011] (2) It is difficult to determine the appropriate test frequency range in the electrical measurement method;

[0012] (3) The accuracy of electrical measurement is greatly affected by the environment. Summary of the invention

[0013] The purpose of the present invention is to solve the problems of the existing electrical testing method, that is, the test time is long, it is difficult to determine the appropriate test frequency range, and the accuracy is greatly affected by the environment.

[0014] In order to achieve the above object, one aspect of the present invention is to propose a method for determining monitoring points of icebreaker icebreaking impact, which is characterized by comprising the following steps:

[0015] Steps for establishing a numerical model of impact vibration of an icebreaker to be subjected to icebreaking tests;

[0016] Performing modal analysis on the impact vibration numerical model to obtain characteristic frequencies and vibration modes of the icebreaker, and expanding the characteristic frequencies of the icebreaker within a given range to obtain test frequencies;

[0017] In the impact vibration numerical model, the hull part of the icebreaker at 1 meter above the waterline and below is selected, and the hull part is regarded as a rigid body to obtain the steps of simplifying the numerical model;

[0018] The step of simulating the interaction between the icebreaker and the ice layer and the stress of the icebreaker under different ice conditions by using the finite element method according to the ice condition data of the icebreaking test and the simplified numerical model, and obtaining simulation results of the impact vibration response and noise response of the icebreaker;

[0019] Compare and analyze the characteristic frequencies and vibration modes of the icebreaker and the simulation results of the impact vibration response and noise response of the icebreaker to obtain the vibration characteristics of the hull corresponding to different icebreaking speeds;

[0020] The step of determining the monitoring points of the icebreaking test according to the hull vibration characteristics and in combination with the icebreaking conditions and icebreaking speed.

[0021] Another aspect of the present invention is to provide a device for determining monitoring points of icebreaker icebreaking impact, which is characterized by comprising the following modules:

[0022] A module for building a numerical model of the impact vibration of an icebreaker to be tested on ice;

[0023] Performing modal analysis on the impact vibration numerical model to obtain the characteristic frequency and vibration mode of the icebreaker, and expanding the characteristic frequency of the icebreaker within a given range to obtain a test frequency module;

[0024] In the impact vibration numerical model, the hull part of the icebreaker at 1 meter above the waterline and below is selected, and the hull part is regarded as a rigid body to obtain a module of a simplified numerical model;

[0025] A module for simulating the interaction between the icebreaker and the ice layer and the stress of the icebreaker under different ice conditions using the finite element method according to the ice condition data of the icebreaking test and the simplified numerical model, and obtaining the simulation results of the impact vibration response and noise response of the icebreaker;

[0026] Compare and analyze the characteristic frequencies and vibration modes of the icebreaker, as well as the simulation results of the impact vibration response and noise response of the icebreaker, and obtain the module of the hull vibration characteristics corresponding to different icebreaking speeds;

[0027] According to the hull vibration characteristics, combined with icebreaking conditions and icebreaking speed, a module for determining monitoring points for icebreaking tests.

[0028] Another aspect of the present invention is to provide a vibration and noise testing method for icebreaker icebreaking impact, which is characterized by comprising the following steps:

[0029] The step of obtaining vibration response data and noise response data of the icebreaker under non-icebreaking conditions and icebreaking conditions obtained in the icebreaking test, wherein the icebreaking test adopts the above-mentioned method for determining monitoring points of icebreaking impact of the icebreaker to determine the test frequency and monitoring points;

[0030] The steps of comparing vibration response data and noise response data of the icebreaker under non-icebreaking conditions and icebreaking conditions, performing difference analysis of ice loads, and obtaining vibration signals and noise signals after eliminating interference noise;

[0031] The steps of dividing and intercepting the vibration signal and the noise signal after removing the interference noise, and performing a mean removal process on the vibration signal and the noise signal after the division and interception;

[0032] The step of processing the vibration signal after the mean value processing to obtain the final result of the vibration response of the icebreaker;

[0033] The step of processing the noise signal after the mean processing to obtain the final result of the noise response of the icebreaker.

[0034] Further, a preferred embodiment is provided, wherein the step of processing the vibration signal after the mean value processing to obtain the final result of the vibration response of the icebreaker comprises the following steps:

[0035] The vibration signal after de-averaging is analyzed by combining wavelet denoising and short-time Fourier transform methods to obtain the vibration acceleration amplitude spectrum as the final result of the vibration response of the icebreaker:

[0036]

[0037] Among them, g ω,t (t) = g(t-τ)e -iωt is the integral kernel function, e -iωt is the frequency-limited function, g(t-τ) is the time-limited function, G x (ω,τ) is the signal frequency component reflecting the frequency ω of x(t) at time τ; x(t) is the objective function of the vibration signal after de-averaging.

[0038] Furthermore, a preferred embodiment is provided, wherein the step of processing the noise signal after the mean value processing to obtain the final result of the noise response of the icebreaker comprises the following steps:

[0039] The noise signal measured by the microphone in the noise signal after de-averaging is processed by short-time Fourier transform method to obtain the sound pressure amplitude spectrum of each typical cabin.

[0040] The sound pressure amplitude spectrum of each typical cabin is converted to obtain the sound pressure value at each center frequency of the octave band from 31.5 to 8000 Hz:

[0041]

[0042] Among them, f 2i is the upper frequency limit of each center frequency band, f 1i is the lower frequency limit of each center frequency band, p i It is the total sound pressure value within each center frequency band;

[0043] Obtain the sound pressure level at each center frequency of the octave from 31.5 to 8000 Hz:

[0044]

[0045] Where p0 = 2.0 × 10 -5 Pa, p0 is the reference sound pressure; the sound pressure level at each center frequency of the octave band of 31.5 to 8000 Hz is A-weighted to obtain the A sound level at each center frequency of the octave band of 31.5 to 8000 Hz;

[0046] L Ai =L Pi +Δ Ai dB(A);

[0047] Among them, Δ Ai is the modified value of A weighting;

[0048] For the noise signal measured by the sound level meter in the noise signal after the mean value processing, obtain its equivalent continuous A sound level:

[0049]

[0050] Where T is the measurement time, L A (t) is the value of the A sound level measured at each moment;

[0051] L Ai and L Aeq As the final result of the noise response of the icebreaker.

[0052] Further, a preferred embodiment is provided, wherein the ice-breaking experiment is carried out using the following method:

[0053] Step 1: Determine the test frequency and monitoring points using the above-mentioned method for determining monitoring points of icebreaker icebreaking impact;

[0054] Step 2: Install a vibration acceleration sensor at the monitoring point in the hull of the icebreaker; arrange a microphone and a sound level meter in a typical cabin of the icebreaker, wherein the vibration acceleration sensor is used to collect vibration response data; and the microphone and the sound level meter are used to collect noise response data;

[0055] Step 3: Conduct vibration and noise tests in an open area without ice to obtain vibration response data and noise response data of the icebreaker under non-icebreaking conditions;

[0056] Step 4: Perform vibration and noise tests under icebreaking conditions according to the test frequency and given test conditions to obtain vibration response data and noise response data of the icebreaker under icebreaking conditions.

[0057] Another aspect of the present invention is to provide a vibration and noise testing device for icebreaker icebreaking impact, which is characterized by comprising the following modules:

[0058] A module for obtaining vibration response data and noise response data of an icebreaker under non-icebreaking conditions and icebreaking conditions obtained in an icebreaking test, wherein the icebreaking test adopts the above-mentioned method for determining monitoring points of icebreaking impact of an icebreaker to determine the test frequency and monitoring points;

[0059] Compare the vibration response data and noise response data of the icebreaker under non-icebreaking conditions and icebreaking conditions, perform differential analysis of ice loads, and obtain a module for vibration signals and noise signals after eliminating interference noise;

[0060] A module for dividing and intercepting the vibration signal and the noise signal after removing the interference noise, and performing de-averaging processing on the vibration signal and the noise signal after the division and interception;

[0061] A module for processing the vibration signal after the mean value processing to obtain the final result of the vibration response of the icebreaker;

[0062] The module processes the noise signal after the mean processing to obtain the final result of the noise response of the icebreaker.

[0063] Another aspect of the present invention is to propose a computer program product, characterized in that it includes: a processor and a memory, the memory is used to store executable instructions of the processor, and the processor is configured to execute the above-mentioned method for determining monitoring points of icebreaker icebreaking impact or the above-mentioned method for testing vibration and noise of icebreaker icebreaking impact by executing the executable instructions.

[0064] Another aspect of the present invention is to propose a computer storage medium, characterized in that a computer program is stored in the storage medium, and when the computer program is run, the above-mentioned method for determining monitoring points of icebreaker icebreaking impact or the above-mentioned method for testing vibration and noise of icebreaker icebreaking impact is executed.

[0065] Another aspect of the present invention is to propose an application of a vibration and noise test method for icebreaker icebreaking impact in a vibration and noise test for icebreaker icebreaking impact.

[0066] Compared with the prior art solutions, the present invention has the following beneficial effects:

[0067] 1. The vibration and noise testing method for icebreaker icebreaking impact described in the present invention combines simulation analysis with actual icebreaking test, conducts numerical simulation analysis on the vibration and noise results of the icebreaker under ice impact, and then applies the analysis results to the actual icebreaking test, so as to quickly determine the test frequency and the location of monitoring points.

[0068] 2. The vibration and noise testing method for icebreaking impact of an icebreaker described in the present invention obtains the test frequency through modal analysis and the monitoring point position through finite element method, which can greatly shorten the time required for the icebreaking test and thus reduce the test time of the vibration and noise test.

[0069] 3. The vibration and noise testing method for icebreaking impact of an icebreaker described in the present invention obtains the test frequency through modal analysis and the monitoring point position through finite element method, which can guide the icebreaking test to collect signals more accurately, thereby improving the accuracy of the vibration and noise testing.

[0070] 4. The vibration and noise testing method for icebreaker icebreaking impact described in the present invention obtains the vibration signal and noise signal after eliminating the interference noise through difference analysis, which can eliminate the interference of environmental noise and thus greatly reduce the impact of the environment on the vibration and noise test.

[0071] 5. The vibration and noise testing method for icebreaker icebreaking impact of the present invention is carried out through actual icebreaking test, close to the actual operating environment, and actually drives the icebreaker to sail in the ice environment for testing, so as to obtain the most authentic and reliable vibration and noise test results.

[0072] The vibration and noise testing method for icebreaker icebreaking impact and its application described in the present invention are suitable for quantitatively evaluating the vibration response and noise response caused by the icebreaker icebreaking impact. BRIEF DESCRIPTION OF THE DRAWINGS

[0073] Figure 1 A flowchart of a vibration and noise testing method for icebreaker icebreaking impact in one embodiment of the present invention;

[0074] Figure 2 This is a schematic diagram of the common layout of the main cabins of existing icebreakers;

[0075] Figure 3 Based on Figure 2 Schematic diagram of the arrangement of monitoring points on the main deck of the icebreaker shown;

[0076] Figure 4 Based on Figure 2 The schematic diagram of the monitoring point arrangement of the superstructure bridge deck of the icebreaker shown;

[0077] Figure 5 Based on Figure 2 Schematic diagram of the sound level meter and microphone arrangement of the icebreaker shown. DETAILED DESCRIPTION

[0078] The present invention will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms fall within the scope limited by the appended claims of the application equally.

[0079] In order to make the technical solutions and advantages of the present invention more clearly described, the specific implementation methods of the present invention will be further described in detail and completely in conjunction with the accompanying drawings. The various implementation methods described below are only part of the preferred solutions of the present invention, rather than all implementation methods; the various implementation methods described below are intended to explain the present invention and cannot be understood as limitations on the present invention; the reasonable combination of technical features defined in the various implementation methods of the present invention, and all other implementation methods obtained by ordinary technicians in the field without creative work based on the implementation methods of the present invention, are within the scope of protection of the present invention.

[0080] Implementation Method 1

[0081] Combination Figure 1 This embodiment describes a method for determining monitoring points of icebreaker icebreaking impact, and the specific implementation contents are as follows:

[0082] The method comprises the following steps:

[0083] Steps for establishing a numerical model of impact vibration of an icebreaker to be subjected to icebreaking tests;

[0084] Performing modal analysis on the impact vibration numerical model to obtain characteristic frequencies and vibration modes of the icebreaker, and expanding the characteristic frequencies of the icebreaker within a given range to obtain test frequencies;

[0085] In the impact vibration numerical model, the hull part of the icebreaker at 1 meter above the waterline and below is selected, and the hull part is regarded as a rigid body to obtain the steps of simplifying the numerical model;

[0086] The step of simulating the interaction between the icebreaker and the ice layer and the stress of the icebreaker under different ice conditions by using the finite element method according to the ice condition data of the icebreaking test and the simplified numerical model, and obtaining simulation results of the impact vibration response and noise response of the icebreaker;

[0087] Compare and analyze the characteristic frequencies and vibration modes of the icebreaker and the simulation results of the impact vibration response and noise response of the icebreaker to obtain the vibration characteristics of the hull corresponding to different icebreaking speeds;

[0088] The step of determining the monitoring points of the icebreaking test according to the hull vibration characteristics and in combination with the icebreaking conditions and icebreaking speed.

[0089] In this embodiment, the characteristic frequency represents the natural vibration frequency of the icebreaker without external interference; the vibration mode represents the vibration pattern of the icebreaker at a specific frequency, specifically including the vibration form and vibration amplitude of each point of the icebreaker.

[0090] In this embodiment, the simulation result of the impact vibration response of the icebreaker obtained by simulating using the finite element method is a simulation result of the vibration response of the icebreaker under the action of its own motion and external load (ice load impact).

[0091] In this embodiment, the ice condition data of the ice breaking test is data collected in advance.

[0092] The ice condition data refers to the ice condition data of the icebreaking test scene, including ice geometric parameters (ice layer thickness, ice layer area, etc.) and mechanical parameters (ice density, ice crystal structure, etc.), which can be obtained through actual collection; if the actual collection conditions do not allow (such as navigation in polar ice areas, etc.), the ice condition data can also be downloaded from the Internet.

[0093] In this embodiment, the icebreaking load model to which the icebreaker is subjected during the actual icebreaking operation is related to factors such as ice conditions, mechanical strength of ice, ice layer failure mode, and icebreaker speed. To simplify the calculation, the actual situation is appropriately simplified: the difference in ice thickness and mechanical strength in the icebreaking area is ignored, and the buckling and shear failure of the ice layer are not considered.

[0094] Since the main action area of ​​the icebreaking load on the ship is the bow during the icebreaking process, the icebreaker can be simplified to the hull plate below the waterline, and the height position 1 meter above the waterline is considered to reduce the influence of the truncation boundary; that is, the simplified numerical model obtained by simplifying the impact vibration numerical model is mainly to extract the main action area of ​​the icebreaker in contact with the ice load, thereby improving the simulation efficiency and ensuring the accuracy of the simulation results.

[0095] In this implementation, according to the vibration simulation results, the hull vibration (characteristic) can be divided into total vibration (characteristic) and local vibration (characteristic):

[0096] In the case of total vibration, monitoring points (or vibration monitoring points, vibration acceleration measuring points) are mainly arranged at key parts of the hull structure such as the hull longitudinals, strong transverse beams and bottom keels;

[0097] In the case of local vibration, the monitoring points are mainly arranged at the center of the plate grid, the middle of the crossbeam, and the intersection of the longitudinal girder and the crossbeam where the hull structure has large vibration deformation.

[0098] In this implementation manner, the determination of the monitoring points is more specifically as follows:

[0099] The monitoring points of the icebreaking test are determined according to the hull vibration characteristics and in combination with the icebreaking conditions and icebreaking speed.

[0100] The vibration modes in the hull vibration characteristics are analyzed to determine the main vibration areas of the icebreaker structure; based on the layout of the icebreaker structure and the difficulty of monitoring, monitoring points (i.e., monitoring points for measuring vibration responses on the actual icebreaker during icebreaking tests) are determined from the main vibration areas.

[0101] Implementation Method 2

[0102] Combination Figure 1 This embodiment describes a device for determining monitoring points of icebreaker impact. The specific implementation contents are as follows:

[0103] The device comprises the following modules:

[0104] A module for building a numerical model of the impact vibration of an icebreaker to be tested on ice;

[0105] Performing modal analysis on the impact vibration numerical model to obtain the characteristic frequency and vibration mode of the icebreaker, and expanding the characteristic frequency of the icebreaker within a given range to obtain a test frequency module;

[0106] In the impact vibration numerical model, the hull part of the icebreaker at 1 meter above the waterline and below is selected, and the hull part is regarded as a rigid body to obtain a module of a simplified numerical model;

[0107] A module for simulating the interaction between the icebreaker and the ice layer and the stress of the icebreaker under different ice conditions using the finite element method according to the ice condition data of the icebreaking test and the simplified numerical model, and obtaining the simulation results of the impact vibration response and noise response of the icebreaker;

[0108] Compare and analyze the characteristic frequencies and vibration modes of the icebreaker, as well as the simulation results of the impact vibration response and noise response of the icebreaker, and obtain the module of the hull vibration characteristics corresponding to different icebreaking speeds;

[0109] According to the hull vibration characteristics, combined with icebreaking conditions and icebreaking speed, a module for determining monitoring points for icebreaking tests.

[0110] In this embodiment, the device for determining monitoring points of icebreaker icebreaking impact is used to implement the method for determining monitoring points of icebreaker icebreaking impact in the above embodiment.

[0111] Implementation Method 3

[0112] Combination Figure 1 This embodiment describes a vibration and noise test method for icebreaker icebreaking impact, and the specific implementation contents are as follows:

[0113] The method comprises the following steps:

[0114] The step of obtaining vibration response data and noise response data of the icebreaker under non-icebreaking conditions and icebreaking conditions obtained in the icebreaking test; wherein the icebreaking test adopts the above-mentioned method for determining monitoring points of icebreaking impact of the icebreaker to determine the test frequency and monitoring points;

[0115] The steps of comparing vibration response data and noise response data of the icebreaker under non-icebreaking conditions and icebreaking conditions, performing difference analysis of ice loads, and obtaining vibration signals and noise signals after eliminating interference noise;

[0116] The steps of dividing and intercepting the vibration signal and the noise signal after removing the interference noise, and performing a mean removal process on the vibration signal and the noise signal after the division and interception;

[0117] The step of processing the vibration signal after the mean value processing to obtain the final result of the vibration response of the icebreaker;

[0118] The step of processing the noise signal after the mean processing to obtain the final result of the noise response of the icebreaker.

[0119] In this embodiment, during the actual operation of the icebreaker, the generator, propeller and other equipment of the icebreaker and the environment in which the icebreaker is located will generate noise, which will affect the accuracy of the data obtained in the icebreaking test, and these noises can be called interference noise.

[0120] In this embodiment, the difference analysis refers to performing difference processing on the response data under different icebreaking speeds (i.e., under icebreaking conditions) and the response data under non-icebreaking conditions to eliminate the influence of equipment such as generators and propellers and environmental noise (i.e., interference noise).

[0121] In this embodiment, during the icebreaking operation of the icebreaker, under the action of intermittent or non-continuous icebreaking impact loads, the fluctuation amplitude of the hull structure vibration and cabin noise response time history signals collected by each sensor is large, and has obvious non-stationary characteristics. Reasonable division and interception of the signals can improve the accuracy of the time domain analysis of the signals.

[0122] In this implementation, the signal is de-averaged to reduce the offset and phase difference between the signals, thereby improving the clarity of the signal and making the subsequent analysis results more accurate.

[0123] In this embodiment, the results of a vibration noise testing method for icebreaker icebreaking impact can also be evaluated according to a monitoring point determination method for icebreaker icebreaking impact in the above embodiment, specifically:

[0124] A monitoring point determination method for icebreaker icebreaking impact in the above-mentioned embodiment is used to obtain simulation results of icebreaker impact vibration response and noise response;

[0125] The vibration and noise response of the icebreaker are finally obtained by using the result of the vibration and noise test method of the icebreaker icebreaking impact in the above-mentioned embodiment;

[0126] According to the simulation results of the impact vibration response and noise response of the icebreaker and the final results of the vibration response and noise response of the icebreaker, the curve characteristics, spectrum characteristics and related indicators of the two are compared, and error analysis is carried out;

[0127] Results of an evaluation of the vibration and noise testing method for icebreaker icebreaking impact based on error analysis results.

[0128] Implementation Method 4

[0129] Combination Figure 1 This embodiment is described. This embodiment is a further limitation of the vibration and noise testing method for icebreaker icebreaking impact described in the third embodiment. The specific implementation contents are as follows:

[0130] The step of processing the vibration signal after the mean value processing to obtain the final result of the vibration response of the icebreaker includes the following steps:

[0131] The vibration signal after de-averaging is analyzed by combining wavelet denoising and short-time Fourier transform methods to obtain the vibration acceleration amplitude spectrum as the final result of the vibration response of the icebreaker:

[0132]

[0133] Among them, g ω,t (t) = g(t-τ)e -iωt is the integral kernel function, e -iωt is the frequency-limited function, g(t-τ) is the time-limited function, G x (ω,τ) is the signal frequency component reflecting the frequency ω of x(t) at time τ; x(t) is the objective function of the vibration signal after de-averaging.

[0134] Implementation Method 5

[0135] Combination Figure 1 This embodiment is described. This embodiment is a further limitation of the vibration and noise testing method for icebreaker icebreaking impact described in the third embodiment. The specific implementation contents are as follows:

[0136] The step of processing the noise signal after the mean value removal process to obtain the final result of the noise response of the icebreaker includes the following steps:

[0137] The noise signal measured by the microphone in the noise signal after de-averaging is processed by short-time Fourier transform method to obtain the sound pressure amplitude spectrum of each typical cabin.

[0138] The sound pressure amplitude spectrum of each typical cabin is converted to obtain the sound pressure value at each center frequency of the octave band from 31.5 to 8000 Hz:

[0139]

[0140] Among them, f 2i is the upper frequency limit of each center frequency band, f 1i is the lower frequency limit of each center frequency band, p i It is the total sound pressure value within each center frequency band;

[0141] Obtain the sound pressure level at each center frequency of the octave from 31.5 to 8000 Hz:

[0142]

[0143] Where p0 = 2.0 × 10-5 Pa, p0 is the reference sound pressure; the sound pressure level at each center frequency of the octave band of 31.5 to 8000 Hz is A-weighted to obtain the A sound level at each center frequency of the octave band of 31.5 to 8000 Hz;

[0144] L Ai =L Pi +Δ Ai dB(A);

[0145] Among them, Δ Ai is the modified value of A weighting;

[0146] For the noise signal measured by the sound level meter in the noise signal after the mean value processing, obtain its equivalent continuous A sound level:

[0147]

[0148] Where T is the measurement time, L A (t) is the value of the A sound level measured at each moment;

[0149] L Ai and L Aeq As the final result of the noise response of the icebreaker.

[0150] In this embodiment, the noise signal after the mean value processing includes the noise signal measured by the microphone after the mean value processing and the noise signal measured by the sound level meter after the mean value processing;

[0151] The noise signal measured by the sound level meter after the de-averaging process is a non-steady-state noise signal.

[0152] Implementation Method 6

[0153] Combination Figure 1 This embodiment is described. This embodiment is a further limitation of the vibration and noise testing method for icebreaker icebreaking impact described in the third embodiment. The specific implementation contents are as follows:

[0154] The ice-breaking experiment was carried out using the following method:

[0155] Step 1: Determine the test frequency and monitoring points using the above-mentioned method for determining monitoring points of icebreaker icebreaking impact;

[0156] Step 2: Install a vibration acceleration sensor at the monitoring point in the hull of the icebreaker; arrange a microphone and a sound level meter in a typical cabin of the icebreaker; wherein the vibration acceleration sensor is used to collect vibration response data; and the microphone and the sound level meter are used to collect noise response data;

[0157] Step 3: Conduct vibration and noise tests in an open area without ice to obtain vibration response data and noise response data of the icebreaker under non-icebreaking conditions;

[0158] Step 4: Perform vibration and noise tests under icebreaking conditions according to the test frequency and given test conditions to obtain vibration response data and noise response data of the icebreaker under icebreaking conditions.

[0159] In this implementation, in order to eliminate the influence of excitation from other equipment, a vibration and noise test is first performed in an ice-free open area.

[0160] In this embodiment, the typical cabins are known based on the actual ship structure of the icebreaker, and refer to the main cabins where the crew members work and live. The noise results of these cabins are relatively important.

[0161] In this embodiment, during the icebreaking process, the ice layer will significantly increase the resistance of the hull when it moves forward, resulting in unstable speed of the icebreaker. It is difficult to maintain a constant speed. Therefore, each icebreaking speed of the icebreaking test conditions is controlled within a small deviation range.

[0162] At the same time, since the ice load impact size and impact position on the icebreaker are different at different speeds (icebreaking speeds), the setting of monitoring points is closely related to the speed.

[0163] In order to better handle the changes in the icebreaking speed of icebreakers, the icebreaking test can be closely combined with the finite element method simulation based on a simplified numerical model:

[0164] First, during the actual measurement of the icebreaking test, a speedometer can be used to monitor the icebreaking speed in real time;

[0165] Then, the icebreaking speed obtained by real-time monitoring can be used in a method for determining monitoring points of icebreaking impact of an icebreaker in the above-mentioned implementation mode, that is, the icebreaking speed obtained by real-time monitoring is used as an input parameter in finite element method simulation, which can improve the accuracy and richness of the numerical model;

[0166] Finally, the icebreaker was rearranged according to the monitoring points obtained by finite element method simulation, and the icebreaking test was repeated using the previous icebreaking speed.

[0167] In this embodiment, in order to investigate the vibration effect of icebreaking impact on the local structure of the main living and working areas of the hull and the noise effect on the key cabins of the ship, it is necessary to reasonably arrange monitoring points for monitoring vibration response (also called vibration acceleration measurement points) and noise measurement points for monitoring typical cabin noise response (i.e., microphone and sound level meter setting points) on the icebreaker:

[0168] In this embodiment, in the step of determining the monitoring points of the icebreaking test according to the hull vibration characteristics, combined with the icebreaking conditions and icebreaking speed, it is also necessary to combine the structure of the icebreaker, specifically:

[0169] According to the structural diagram of the bridge deck, the measuring points (monitoring points) are evenly arranged at the intersection of the deck longitudinal girders and beams, the mid-span position of the beams between the longitudinal girders, and the center position of the local plate grid surrounded by the beams and longitudinal girders;

[0170] As attached Figure 3 As shown in the figure, according to the layout structure diagram of the main deck midship living area, monitoring points are arranged on the floors of the dining room, lounge and corridor in the main deck living area;

[0171] As attached Figure 4 As shown in the figure, according to the bow main deck structure diagram, the monitoring points are evenly arranged on the bow deck.

[0172] As attached Figure 5 As shown in FIG. 1 , microphones and sound level meters are arranged in typical cabins such as the lounge on the main deck amidships of the icebreaker, the wheelhouse, the main engine room, and the bow equipment maintenance cabin. The microphone is arranged in the center of each main test cabin.

[0173] In this embodiment, during each icebreaking test, the icebreaker is first reversed back to open waters from the position reached in the previous icebreaking test, and then an icebreaking test is carried out on the complete broken layer at a certain speed, and the vibration acceleration response and noise response data of the icebreaker are measured at the same time. Until the icebreaker can no longer move forward on the ice layer, this icebreaking test is completed and preparations are made for the next icebreaking test.

[0174] In this embodiment, according to different ice thicknesses, the icebreaker conducts icebreaking tests in two ways: collision type and continuous type.

[0175] In this embodiment, when the collision-type icebreaking method is used for icebreaking operations (icebreaking test), the single icebreaking distance is 1 / 2L to 2 / 3L (L is the ship length). After each collision, the icebreaker stops, and the ship is reversed to a certain distance, and then the second collision and icebreaking are performed forward. Generally, the reverse distance is 2L to 3L; during the second icebreaking, the icebreaking position is selected to the left (or right) side of the first icebreaking position; during the third collision and icebreaking, the icebreaking position is on the other side of the position during the first collision and icebreaking, and the icebreaking is performed alternately left and right in this way, and the width of the channel opened up by icebreaking is kept at 1.5B to 2B (B is the ship width).

[0176] In this embodiment, when the ice layer is relatively thin, a continuous icebreaking method can be used for icebreaking operations; at this time, the icebreaker climbs onto the ice layer at different icebreaking speeds, relies on the weight of the bow to crush the ice layer, and then opens up a route, relying on the powerful thrust of the main engine to forcibly pass through the ice layer.

[0177] Implementation Method 7

[0178] Combination Figure 1 This embodiment describes a vibration and noise testing device for icebreaker icebreaking impact, and the specific implementation contents are as follows:

[0179] The device comprises the following modules:

[0180] A module for obtaining vibration response data and noise response data of an icebreaker under non-icebreaking conditions and icebreaking conditions obtained in an icebreaking test; wherein the icebreaking test adopts the above-mentioned method for determining monitoring points of icebreaking impact of an icebreaker to determine the test frequency and monitoring points;

[0181] Compare the vibration response data and noise response data of the icebreaker under non-icebreaking conditions and icebreaking conditions, perform differential analysis of ice loads, and obtain a module for vibration signals and noise signals after eliminating interference noise;

[0182] A module for dividing and intercepting the vibration signal and the noise signal after removing the interference noise, and performing de-averaging processing on the vibration signal and the noise signal after the division and interception;

[0183] A module for processing the vibration signal after the mean value processing to obtain the final result of the vibration response of the icebreaker;

[0184] The module processes the noise signal after the mean processing to obtain the final result of the noise response of the icebreaker.

[0185] Implementation Method 8

[0186] This embodiment provides an application of a vibration and noise test method for icebreaker icebreaking impact in vibration and noise testing of icebreaker icebreaking impact:

[0187] The vibration and noise testing method for icebreaking impact of an icebreaker can be applied to vibration and noise testing for icebreaking impact of various icebreakers.

[0188] The technical solution provided by the present invention is further described in detail above through several specific implementation modes in order to highlight the advantages and benefits of the technical solution provided by the present invention. However, the several specific implementation modes described above are not intended to be used as limitations on the present invention. Any reasonable changes and improvements to the present invention, reasonable combinations of implementation modes and equivalent substitutions based on the spirit and principles of the present invention should be included in the protection scope of the present invention.

[0189] The above description is only a preferred embodiment of the present invention, and does not limit the implementation mode and protection scope of the present invention. For those skilled in the art, it should be aware that all solutions obtained by equivalent substitutions and obvious changes made using the description and illustrations of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for determining monitoring points of icebreaker icebreaking impact, characterized in that: The following steps are involved: Steps for establishing a numerical model of impact vibration of an icebreaker to be subjected to icebreaking tests; The step of performing modal analysis on the impact vibration numerical model to obtain the characteristic frequency and vibration mode of the icebreaker and expanding the characteristic frequency of the icebreaker to a given range to obtain a test frequency; In the impact vibration numerical model, the hull part of the icebreaker at 1 meter above the waterline and below is selected, and the hull part is regarded as a rigid body to obtain the steps of simplifying the numerical model; The step of simulating the interaction between the icebreaker and the ice layer and the stress of the icebreaker under different ice conditions by using the finite element method according to the ice condition data of the icebreaking test and the simplified numerical model, and obtaining simulation results of the impact vibration response and noise response of the icebreaker; Compare and analyze the characteristic frequencies and vibration modes of the icebreaker and the simulation results of the impact vibration response and noise response of the icebreaker to obtain the vibration characteristics of the hull corresponding to different icebreaking speeds; The step of determining the monitoring points of the icebreaking test according to the hull vibration characteristics and in combination with the icebreaking conditions and icebreaking speed.

2. A device for determining monitoring points of icebreaker icebreaking impact, characterized in that: Includes the following modules: A module for building a numerical model of the impact vibration of an icebreaker to be tested on ice; Performing modal analysis on the impact vibration numerical model to obtain the characteristic frequency and vibration mode of the icebreaker, and expanding the characteristic frequency of the icebreaker within a given range to obtain a test frequency module; In the impact vibration numerical model, the hull part of the icebreaker at 1 meter above the waterline and below is selected, and the hull part is regarded as a rigid body to obtain a module of a simplified numerical model; A module for simulating the interaction between the icebreaker and the ice layer and the stress of the icebreaker under different ice conditions using the finite element method according to the ice condition data of the icebreaking test and the simplified numerical model, and obtaining the simulation results of the impact vibration response and noise response of the icebreaker; Compare and analyze the characteristic frequencies and vibration modes of the icebreaker, as well as the simulation results of the impact vibration response and noise response of the icebreaker, and obtain the module of the hull vibration characteristics corresponding to different icebreaking speeds; According to the hull vibration characteristics, combined with icebreaking conditions and icebreaking speed, a module for determining monitoring points for icebreaking tests.

3. A vibration and noise testing method for icebreaker icebreaking impact, characterized in that: The following steps are involved: The step of obtaining vibration response data and noise response data of the icebreaker under non-icebreaking conditions and icebreaking conditions obtained in the icebreaking test; wherein the icebreaking test adopts the monitoring point determination method for icebreaking impact of an icebreaker as described in claim 1 to determine the test frequency and monitoring points; The steps of comparing vibration response data and noise response data of the icebreaker under non-icebreaking conditions and icebreaking conditions, performing difference analysis of ice loads, and obtaining vibration signals and noise signals after eliminating interference noise; The steps of dividing and intercepting the vibration signal and the noise signal after removing the interference noise, and performing a mean removal process on the vibration signal and the noise signal after the division and interception; The step of processing the vibration signal after the mean value processing to obtain the final result of the vibration response of the icebreaker; The step of processing the noise signal after the mean processing to obtain the final result of the noise response of the icebreaker.

4. The vibration and noise testing method for icebreaker icebreaking impact according to claim 3 is characterized in that: The step of processing the vibration signal after the mean value processing to obtain the final result of the vibration response of the icebreaker includes the following steps: The vibration signal after de-averaging is analyzed by combining wavelet denoising and short-time Fourier transform methods to obtain the vibration acceleration amplitude spectrum as the final result of the vibration response of the icebreaker: Among them, g ω,t (t) = g(t-τ)e -iωt is the integral kernel function, e -iωt is the frequency-limited function, g(t-τ) is the time-limited function, G x (ω,τ) is the signal frequency component reflecting the frequency ω of x(t) at time τ; x(t) is the objective function of the vibration signal after de-averaging.

5. The vibration and noise testing method for icebreaker icebreaking impact according to claim 3 is characterized in that: The step of processing the noise signal after the mean value removal process to obtain the final result of the noise response of the icebreaker includes the following steps: The noise signal measured by the microphone in the noise signal after de-averaging is processed by short-time Fourier transform method to obtain the sound pressure amplitude spectrum of each typical cabin. The sound pressure amplitude spectrum of each typical cabin is converted to obtain the sound pressure value at each center frequency of the octave band from 31.5 to 8000 Hz: Among them, f 2i is the upper frequency limit of each center frequency band, f 1i is the lower frequency limit of each center frequency band, p i It is the total sound pressure value within each center frequency band; Obtain the sound pressure level at each center frequency of the octave from 31.5 to 8000 Hz: Where p0 = 2.0 × 10 -5 Pa, p0 is the reference sound pressure; the sound pressure level at each center frequency of the octave band of 31.5 to 8000 Hz is A-weighted to obtain the A sound level at each center frequency of the octave band of 31.5 to 8000 Hz; L Ai =L Pi +D Ai dB(A); Among them, Δ Ai is the modified value of A weighting; For the noise signal measured by the sound level meter in the noise signal after the mean value processing, obtain its equivalent continuous A sound level: Where T is the measurement time, L A (t) is the value of the A sound level measured at each moment; L Ai and L Aeq As the final result of the noise response of the icebreaker.

6. The vibration and noise testing method for icebreaker icebreaking impact according to claim 3 is characterized in that: The ice-breaking experiment is carried out using the following method: The test frequency and monitoring points are determined by using the method for determining monitoring points of icebreaker icebreaking impact as described in claim 1; A vibration acceleration sensor is installed at a monitoring point in the hull of the icebreaker; a microphone and a sound level meter are arranged in a typical cabin of the icebreaker, wherein the vibration acceleration sensor is used to collect vibration response data; and the microphone and the sound level meter are used to collect noise response data; Conduct vibration and noise tests in open areas without ice to obtain vibration and noise response data of icebreakers under non-icebreaking conditions; Vibration and noise tests under icebreaking conditions are carried out according to the test frequency and given test conditions to obtain vibration response data and noise response data of the icebreaker under icebreaking conditions.

7. A vibration and noise testing device for icebreaker icebreaking impact, characterized in that: Includes the following modules: A module for obtaining vibration response data and noise response data of an icebreaker under non-icebreaking conditions and icebreaking conditions obtained in an icebreaking test, wherein the icebreaking test adopts the method for determining monitoring points of icebreaking impact of an icebreaker as described in claim 1 to determine the test frequency and monitoring points; Compare the vibration response data and noise response data of the icebreaker under non-icebreaking conditions and icebreaking conditions, perform differential analysis of ice loads, and obtain a module for vibration signals and noise signals after eliminating interference noise; A module for dividing and intercepting the vibration signal and the noise signal after removing the interference noise, and performing de-averaging processing on the vibration signal and the noise signal after the division and interception; A module for processing the vibration signal after the mean value processing to obtain the final result of the vibration response of the icebreaker; The module processes the noise signal after the mean processing to obtain the final result of the noise response of the icebreaker.

8. A computer program product comprising: A processor and a memory, characterized in that the memory is used to store executable instructions of the processor, and the processor is configured to execute the monitoring point determination method for icebreaker icebreaking impact described in claim 1 or the vibration and noise testing method for icebreaker icebreaking impact described in any one of claims 3-6 by executing the executable instructions.

9. A computer storage medium, characterized in that The storage medium stores a computer program, and when the computer program is run, the method for determining monitoring points of icebreaker icebreaking impact according to claim 1 or the method for testing vibration and noise of icebreaker icebreaking impact according to any one of claims 3 to 6 is executed.

10. A vibration and noise test method for icebreaker icebreaking impact and its application in vibration and noise test for icebreaker icebreaking impact.

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