Wave load model test bending moment inversion measurement method

Abstract

The invention relates to a bending moment inversion measurement method for a wave load model test. The method comprises the following steps: 1, determining the number and positions of segments of a ship model; 2, designing a measuring beam; thirdly, a laser bending moment measuring system is installed on the measuring beam; step 4, measuring beam calibration: for vertical bending moment measurement and simultaneous vertical and torsion measurement, calibration is carried out by adopting different modes, and calibration is carried out by adopting a step-by-step loading and multi-time calibration mode; 5, obtaining a conversion coefficient of displacement and load based on the calibration data; sixthly, the measuring beam is installed in the ship model shell; and 7, completing the wave load model test according to the test working condition. The relative displacement change of the section needing to be tested is measured through the laser displacement sensor, only 3-5 measuring points need to be arranged, only 6-10 measuring points need to be arranged during torsion load measurement, the laser displacement sensor and supporting facilities can be repeatedly used, cost is saved, the number of the measuring points is small, and mounting and dismounting are convenient.

Description

Technical Field

[0001] The present invention relates to the technical field of ship wave load measurement, in particular to a method for inverse measurement of bending moment in wave load model test. Background Art

[0002] When conducting a wave load model test on a ship, it is necessary to reasonably equivalent the actual ship structure stiffness according to the scale ratio based on the seakeeping tank and corresponding equipment conditions, and design a reasonable wave load measurement beam system accordingly.

[0003] Existing measurement methods include measuring wave vertical bending moment, horizontal bending moment, torque, etc. by pasting strain gauges on the measurement beam and through calibration. However, the process of pasting strain gauges in this measurement method is relatively complex, and multiple strain gauges need to be pasted at each measurement section. The corresponding relationship between strain and bending moment is obtained through calibration; since the strain gauges are relatively fragile, during the process of installing the measurement beam on the ship model after calibration, the measurement points may be damaged and fail due to bumps, etc., affecting the test accuracy and efficiency.

[0004] Therefore, we propose a method for inverse measurement of bending moment in wave load model test. Summary of the Invention

[0005] The applicant of the present invention aims at the above-mentioned shortcomings in the existing production technology and provides a method for inverse measurement of bending moment in wave load model test, so as to measure the relative displacement change of the section to be tested through a laser displacement sensor. Only 3 - 5 measurement points need to be arranged, and the number of measurement points is about the number of sections. When measuring the torsional load, only 6 - 10 measurement points need to be arranged, and the number of measurement points is about twice the number of sections. The laser displacement sensor and supporting facilities can be reused, saving costs, with mature technology, few measurement points, and being convenient for installation and disassembly.

[0006] The technical solution adopted by the present invention is as follows:

[0007] A method for inverse measurement of bending moment in wave load model test includes the following steps:

[0008] The first step: Determine the number and position of the segments of the ship model;

[0009] The second step: Design the measurement beam;

[0010] The third step: Install a laser bending moment measurement system on the measurement beam;

[0011] The fourth step: Calibrate the measurement beam. For the cases of vertical bending moment measurement and simultaneous vertical and torsional measurement, different methods are used for calibration, and the calibration is carried out by gradually increasing the load and calibrating multiple times;

[0012] The fifth step: Based on the calibration data, obtain the conversion coefficient between displacement and load;

[0013] Step 6: Install the measuring beam in the hull model shell;

[0014] Step 7: Complete the wave load model test according to the test conditions.

[0015] It is further characterized in that:

[0016] The laser bending moment measurement system includes a reflector and a laser displacement sensor. The reflector is connected to the measuring beam through a fixing device, and the fixing device and the reflector are connected through a bracket; the laser displacement sensor is fixed on the detachable horizontal beam at the non-measuring section.

[0017] The hull model is divided into four segments, and the bending moments at three sections need to be measured. Five laser displacement sensors are arranged on the detachable horizontal beam at the non-measuring section, which are respectively the first laser displacement sensor, the second laser displacement sensor, the third laser displacement sensor, the fourth laser displacement sensor and the fifth laser displacement sensor from one side to the other side. Reflectors corresponding to the first laser displacement sensor, the second laser displacement sensor, the third laser displacement sensor, the fourth laser displacement sensor and the fifth laser displacement sensor are arranged on the measuring sections, namely the first reflector, the second reflector, the third reflector, the fourth reflector and the fifth reflector. The third reflector is arranged on the middle measuring section, the first laser displacement sensor and the second laser displacement sensor are arranged on one measuring section, and the fourth laser displacement sensor and the fifth laser displacement sensor are arranged on the other measuring section.

[0018] The bending moment is measured by the first laser displacement sensor, the third laser displacement sensor, the fifth laser displacement sensor and the corresponding first reflector, third reflector and fifth reflector.

[0019] The bending moment and torque are measured by the first laser displacement sensor, the second laser displacement sensor, the third laser displacement sensor, the fourth laser displacement sensor, the fifth laser displacement sensor and the corresponding first reflector, second reflector, third reflector, fourth reflector and fifth reflector.

[0020] In Step 4, the measuring beam and the laser bending moment measurement system are placed on the support structure. Weights are hung on the measuring beam, and the weights are placed on the weight trays. The weight trays are connected to the measuring beam through suspension steel wires;

[0021] The bending moment at the maximum bending moment is:

[0022] where m is the weight of the weight (400), in kg; g is the acceleration due to gravity, in m / s 2 ; L5 and L4 are respectively the distances from the weight (400) at the loading position to both ends before loading, in m;

[0023] The measurement profiles corresponding to the first reflector and the second reflector are Profile 1, the measurement profiles corresponding to the fourth reflector and the fifth reflector are Profile 2, and the measurement profile corresponding to the third reflector is Profile 3;

[0024] The bending moment corresponding to Profile 1 is:

[0025] The bending moment corresponding to Profile 2 is:

[0026] The bending moment corresponding to Profile 3 is:

[0027] Among them, L1 is the distance from the first reflector and the second reflector to the weight loading position before loading, with the unit of m; L2 is the distance from the third reflector to the weight loading position before loading, with the unit of m; L3 is the distance from the fourth reflector and the fifth reflector to the weight loading position before loading, with the unit of m;

[0028] Before loading, the distances from the laser displacement sensor to the first reflector and the second reflector are D1, the distance from the laser displacement sensor to the third reflector is D2, and the distances from the laser displacement sensor to the fourth reflector and the fifth reflector are D3;

[0029] After loading, due to the deformation of the structure, the distances from the laser displacement sensor to the first reflector and the second reflector are D1′, the distance from the laser displacement sensor to the third reflector is D2′, and the distances from the laser displacement sensor to the fourth reflector and the fifth reflector are D3′;

[0030] Due to the loading of weights, displacement variables of ΔD1 = D1 - D1′, ΔD2 = D2 - D2′, and ΔD3 = D3 - D3′ are respectively generated at the positions of each reflector 102; the corresponding coefficients k1, k2, k3, k4, k5 of the displacements and bending moments at the three positions are respectively:

[0031] k1 = k2 = M1 / ΔD1;

[0032] k3 = M3 / ΔD2;

[0033] k4 = k5 = M2 / ΔD3;

[0034] k1, k2, k3, k4, k5 are the calibration methods and corresponding calibration coefficients for only vertical bending moment measurement. During the actual test process, the obtained time-domain displacement change results are multiplied by k1, k2, k3, k4, k5 to obtain the time-domain bending moment values.

[0035] In the fourth step, for the coefficient calibration when simultaneously measuring the vertical bending moment and torque, one end of the measuring beam is rigidly fixed, and the weight is suspended at the other end of the measuring beam;

[0036] The bending moment at the maximum bending moment at the left end is: M = m × g × L4;

[0037] where m is the weight of the weight, in kg; g is the acceleration due to gravity, in m / s 2 ; L4 is the distance from the weight loading position before loading to the fixed section, in m;

[0038] The displacement variable at the first reflector is: ΔD 1-1 = ΔD M1 + ΔD T1 ;

[0039] The displacement variable at the second reflector is: ΔD 1-2 = ΔD M1 - ΔD T1 ;

[0040] The displacement variable at the third reflector is: ΔD 3-3 = ΔD M3 ;

[0041] The displacement variable at the fourth reflector is: ΔD 2-4 = ΔD M2 + ΔD T2 ;

[0042] The displacement variable at the fifth reflector is: ΔD 2-5 = ΔD M2 + ΔD T2 ;

[0043] where ΔD M1 , ΔD M2 , ΔD M3 are the displacement variables due to bending at the first, second, and third sections respectively; ΔD T1 , ΔD T2 are the displacement variables due to torque at the first and second sections respectively;

[0044] The bending moment corresponding to the first section is:

[0045] The bending moment corresponding to the second section is:

[0046] The bending moment corresponding to the third section is:

[0047] The torque corresponding to the first and second sections is:

[0048] M T1 = M T2 = m × g × T;

[0049] where T is the distance from the weight application position to the center of the end face of the measuring beam;

[0050] Before loading, the distances from the laser displacement sensor to Reflector 1, Reflector 2, Reflector 3, Reflector 4, and Reflector 5 are D1, D2, and D3 respectively.

[0051] After loading, due to structural deformation, the distance variables from the laser displacement sensor to Reflector 1, Reflector 2, Reflector 3, Reflector 4, and Reflector 5 are ΔD 1-1 , ΔD 1-2 , ΔD 3-3 , ΔD 2-4 , ΔD 2-5 ;

[0052] The corresponding coefficients k M1 、k M2 、k M3 of displacement and bending moment for Section 1, Section 2, and Section 3 and the corresponding coefficients Δk T1 、Δk T2 are respectively:

[0053]

[0054] Multiplying the obtained time-domain displacement change results by the above coefficients can obtain the vertical bending moment and torque values in the time domain.

[0055] The beneficial effects of the present invention are as follows:

[0056] The structure of the present invention is compact, reasonable, and easy to operate. By measuring the relative displacement changes of the sections to be tested with a laser displacement sensor, only 3 - 5 measuring points need to be arranged, and the number of measuring points is approximately the same as the number of sections. For torsional load measurement, only 6 - 10 measuring points need to be arranged, and the number of measuring points is approximately twice the number of sections. The laser displacement sensor and its supporting facilities can be reused, saving costs, with mature technology, few measuring points, and easy installation and disassembly.

[0057] At the same time, the present invention also has the following advantages:

[0058] (1) The displacement changes of different sections can be measured by a laser displacement sensor, and the relationship between displacement changes and bending moment and torque can be obtained through calibration. This method is convenient, fast, and can be disassembled and assembled at any time, avoiding damage to the measuring device during the installation of the measuring beam. Using a laser displacement sensor for testing avoids the use of a large number of acquisition instruments and data transmission wires, can provide more weight margin for model inertia adjustment. At the same time, laser testing has good stability and high accuracy. Description of the Drawings

[0059] Figure 1 It is a schematic structural diagram of the present invention.

[0060] Figure 2 is Figure 1 the top view of

[0061] Figure 3 Schematic diagram of the laser bending moment measurement system of the present invention.

[0062] Figure 4 It is Figure 3 the top view of.

[0063] Figure 5 It is Figure 2 the schematic diagram of the A-A section in

[0064] Figure 6 It is Figure 2 the schematic diagram of the B-B section in

[0065] Figure 7 It is Figure 2 the schematic diagram of the C-C section in

[0066] Figure 8 It is Figure 2 the schematic diagram of the D-D section in

[0067] Figure 9 Schematic diagram of the measurement beam and the laser bending moment measurement system of the present invention placed on the support structure.

[0068] Figure 10 It is for Figure 9 the schematic diagram of simulating the bending load by hanging weights in

[0069] Figure 11 It is Figure 10 the corresponding bending moment distribution schematic diagram after hanging weights in

[0070] Figure 12 Schematic diagram of one end of the measurement beam of the present invention being rigidly fixed.

[0071] Figure 13 It is for Figure 12 the schematic diagram of simulating the bending and torsional loads simultaneously by hanging weights in

[0072] Figure 14 Schematic diagram of the measurement beam and the hanging weights of the present invention.

[0073] Figure 15 It is Figure 13 the corresponding vertical bending moment distribution schematic diagram after hanging weights in

[0074] Wherein: 100, laser bending moment measurement system; 101, laser displacement sensor; 1011, the first laser displacement sensor; 1012, the second laser displacement sensor; 1013, the third laser displacement sensor; 1014, the fourth laser displacement sensor; 1015, the fifth laser displacement sensor; 102, reflector; 1021, the first reflector; 1022, the second reflector; 1023, the third reflector; 1024, the fourth reflector; 1025, the fifth reflector; 103, fixing device; 104, bracket; 200, ship model; 201, measuring beam; 202, beam support structure; 203, end horizontal beam; 204, connecting rubber; 205, DC motor; 206, motor base; 207, universal joint; 208, propeller shaft; 209, propeller; 210, propeller shaft sleeve; 211, steering gear; 212, rudder stock; 213, rudder; 214, gyroscope; 215, gyroscope base; 216, ballast block; 300, baseline; 400, weight; 401, weight tray; 402, suspension wire rope. Detailed implementation manners

[0075] The following combines with the drawings to illustrate the detailed implementation manners of the present invention.

[0076] As Figures 1 - 15 shown, a method for inverse measurement of bending moment in a wave load model test includes the following steps:

[0077] The first step: Determine the number and position of segments of the ship model 200;

[0078] The second step: Design the measuring beam 201;

[0079] The third step: Install the reflector 102 and the laser displacement sensor 101 on the measuring beam 201;

[0080] The fourth step: Calibrate the measuring beam 201. For the cases of vertical bending moment measurement and simultaneous vertical and torsional measurement, different calibration methods are adopted. The calibration is carried out by gradually increasing the load and performing multiple calibrations;

[0081] The fifth step: Based on the calibration data, obtain the conversion coefficient between displacement and load;

[0082] The sixth step: Install the measuring beam 201 in the hull of the ship model 200;

[0083] The seventh step: Complete the wave load model test according to the test conditions.

[0084] The ship model 200 includes various sections. A measuring beam 201 is provided in the ship model 200. The ship model 200 and the measuring beam 201 are connected by a beam support structure 202 and an end horizontal beam 203. The various sections of the ship model 200 are connected by a connecting rubber 204. A motor base 206 is provided inside the ship model 200. A DC motor 205 is provided on the motor base 206. The DC motor 205 is connected to a propeller 209 through a universal joint 207 and a propeller shaft 208, and the propeller shaft sleeve 210 ensures watertightness. A steering gear 211 is provided on the ship model 200. The steering gear 211 is connected to a rudder stock 212, and the rudder stock 212 is connected to a rudder 213. The rudder 213 is controlled by the steering gear 211 to achieve course control. A gyroscope 214 is arranged at the center of gravity of the ship model 200. The gyroscope 214 is connected to the ship model 200 through a gyroscope base 215. The ship model 200 is also provided with ballast blocks 216. The overall weight of the ship model 200 is adjusted by the longitudinally and vertically arranged ballast blocks 216. A baseline 300 is provided at the bottom of the ship model 200.

[0085] The laser bending moment measurement system 100 includes a laser displacement sensor 101, a reflector 102, a fixing device 103, and a bracket 104. The reflector 102 is connected to the measuring beam 201 through the fixing device 103, and the fixing device 103 and the reflector 102 are connected by the bracket 104 to rigidly fix the reflector 102 at the measuring section; the laser displacement sensor 101 is fixed on a detachable horizontal beam at a non-measuring section. The test of the wave bending moment is obtained through the displacement change amount obtained by the laser displacement sensor 101 and after calibration; the displacement is obtained after the laser displacement sensor 101 emits laser to the reflector 102 and the laser is reflected back to the laser displacement sensor 101.

[0086] In one embodiment, the ship model 200 has four sections. According to the number of sections of the wave load model test model, the number and positions of the laser displacement sensors 101 to be arranged are determined. The ship model 200 with four sections needs to measure the bending moments at three sections.

[0087] As Figures 5 - 8 shown, the laser displacement sensor 101 and the corresponding reflector 102 are installed on the measuring beam 201 according to the positions where the loads need to be measured.

[0088] As Figures 2 - 4As shown in the figure, five laser displacement sensors 101 are provided on the detachable horizontal beam of the non-measurement section. From one side to the other side, they are laser displacement sensor one 1011, laser displacement sensor two 1012, laser displacement sensor three 1013, laser displacement sensor four 1014, and laser displacement sensor five 1015. The directions of laser displacement sensor one 1011, laser displacement sensor two 1012, and laser displacement sensor three 1013 are the same. The directions of laser displacement sensor four 1014 and laser displacement sensor five 1015 are the same, and the directions of laser displacement sensor four 1014 and laser displacement sensor five 1015 are opposite to the direction of laser displacement sensor one 1011. On the measurement section, there are reflector one 1021, reflector two 1022, reflector three 1023, reflector four 1024, and reflector five 1025 corresponding to laser displacement sensor one 1011, laser displacement sensor two 1012, laser displacement sensor three 1013, laser displacement sensor four 1014, and laser displacement sensor five 1015. Reflector three 1023 is arranged on the middle measurement section. Laser displacement sensor one 1011 and laser displacement sensor two 1012 are arranged on one side of the measurement section. Laser displacement sensor four 1014 and laser displacement sensor five 1015 are arranged on the other side of the measurement section.

[0089] The bending moment is measured by laser displacement sensor one 1011, laser displacement sensor three 1013, laser displacement sensor five 1015 and the corresponding reflector one 1021, reflector three 1023, reflector five 1025.

[0090] The bending moment and torque are measured by laser displacement sensor one 1011, laser displacement sensor two 1012, laser displacement sensor three 1013, laser displacement sensor four 1014, laser displacement sensor five 1015 and the corresponding reflector one 1021, reflector two 1022, reflector three 1023, reflector four 1024, reflector five 1025.

[0091] As Figures 9 - 11 shown, the measuring beam 201 and the laser bending moment measuring system 100 are placed on the support structure. A weight 400 is hung on the measuring beam 201. The weight 400 is placed on the weight tray 401. The weight tray 401 is connected to the measuring beam 201 through a suspension wire rope 402. The corresponding bending moment distribution is as Figure 11 shown;

[0092] The bending moment at the maximum bending moment is:

[0093] where m is the weight of the weight 400, with the unit of kg; g is the acceleration of gravity, with the unit of m / s 2; L5 and L4 are the distances from the position of the weight 400 before loading to both ends at the loading position, with the unit of m;

[0094] The measurement profiles corresponding to the first reflector 1021 and the second reflector 1022 are Profile 1, the measurement profiles corresponding to the fourth reflector 1024 and the fifth reflector 1025 are Profile 2, and the measurement profile corresponding to the third reflector 1023 is Profile 3;

[0095] The bending moment corresponding to Profile 1 is:

[0096] The bending moment corresponding to Profile 2 is:

[0097] The bending moment corresponding to Profile 3 is:

[0098] Among them, L1 is the distance from the first reflector 1021 and the second reflector 1022 to the loading position of the weight 400 before loading, with the unit of m; L2 is the distance from the third reflector 1023 to the loading position of the weight 400 before loading, with the unit of m; L3 is the distance from the fourth reflector 1024 and the fifth reflector 1025 to the loading position of the weight 400 before loading, with the unit of m.

[0099] Before loading, the distances from the laser displacement sensor 101 to the first reflector 1021 and the second reflector 1022 are D1, the distance from the laser displacement sensor 101 to the third reflector 1023 is D2, and the distances from the laser displacement sensor 101 to the fourth reflector 1024 and the fifth reflector 1025 are D3;

[0100] After loading, due to the deformation of the structure, the distances from the laser displacement sensor 101 to the first reflector 1021 and the second reflector 1022 are D1', the distance from the laser displacement sensor 101 to the third reflector 1023 is D2', and the distances from the laser displacement sensor 101 to the fourth reflector 1024 and the fifth reflector 1025 are D3';

[0101] Due to the loading of the weight 400, displacement variables of ΔD1 = D1 - D1', ΔD2 = D2 - D2', and ΔD3 = D3 - D3' are respectively generated at each reflector 102;

[0102] Then the corresponding coefficients k1, k2, k3, k4, and k5 of displacement and bending moment at the corresponding three positions are respectively:

[0103] k1 = k2 = M1 / ΔD1;

[0104] k3 = M3 / ΔD2;

[0105] k4 = k5 = M2 / ΔD3;

[0106] k1, k2, k3, k4, and k5 are the calibration methods and corresponding calibration coefficients for only measuring the vertical bending moment. During the actual test, the obtained time-domain displacement change results are multiplied by k1, k2, k3, k4, and k5 to obtain the bending moment value in the time domain.

[0107] As Figures 12 - 15 shown, for the coefficient calibration when measuring the vertical bending moment and torque simultaneously, one end of the measuring beam 201 is rigidly fixed, and the weight 400 is suspended at the other end of the measuring beam 201. The corresponding bending moment distribution is as Figure 15 shown.

[0108] The bending moment at the maximum bending moment at the left end is: M = m × g × L4;

[0109] where m is the weight of the weight 400 in kg; g is the acceleration due to gravity in m / s 2 ; L4 is the distance from the loading position of the weight 400 to the fixed section before loading in m;

[0110] Since this loading method simulates the simultaneous action of bending and torsion, the displacement changes of the first reflector 1021 and the second reflector 1022 are no longer the same. Similarly, the displacement changes of the fourth reflector 1024 and the fifth reflector 1025 are also not the same; according to the principle of linear superposition, this loading method can be decomposed into the vertical deformation caused by the vertical load and the rotational deformation caused by the torque action;

[0111] The displacement variable at the first reflector 1021 is: ΔD 1-1 = ΔD M1 + ΔD T1 ;

[0112] The displacement variable at the second reflector 1022 is: ΔD 1-2 = ΔD M1 - ΔD T1 ;

[0113] The displacement variable at the third reflector 1023 is: ΔD 3-3 = ΔD M3 ;

[0114] The displacement variable at the fourth reflector 1024 is: ΔD 2-4 = ΔD M2 + ΔD T2 ;

[0115] The displacement variable at the fifth reflector 1025 is: ΔD 2-5 = ΔD M2 + ΔD T2 ;

[0116] where ΔD M1 , ΔD M2 , ΔDM3 Displacement variables caused by bending at Section 1, Section 2, and Section 3 respectively; ΔD T1 , ΔD T2 Displacement variables caused by torque at Section 1 and Section 2 respectively.

[0117] The bending moment corresponding to Section 1 is:

[0118] The bending moment corresponding to Section 2 is:

[0119] The bending moment corresponding to Section 3 is:

[0120] The torques corresponding to Section 1 and Section 2 are:

[0121] M T1 = M T2 = m × g × T;

[0122] where T is the distance from the position where the weight 400 is applied to the center of the end face of the measuring beam 201;

[0123] Before loading, the distances from the laser displacement sensor 101 to the first reflector 1021, the second reflector 1022, the third reflector 1023, the fourth reflector 1024, and the fifth reflector 1025 are D1, D2, and D3 respectively;

[0124] After loading, due to the deformation of the structure, the distance variables from the laser displacement sensor 101 to the first reflector 1021, the second reflector 1022, the third reflector 1023, the fourth reflector 1024, and the fifth reflector 1025 are ΔD 1-1 , ΔD 1-2 , ΔD 3-3 , ΔD 2-4 , ΔD 2-5 ;

[0125] The corresponding coefficients k M1 , k M2 , k M3 of displacement and bending moment at Section 1, Section 2, and Section 3 and the corresponding coefficients Δk T1 , Δk T2 of displacement and torque are respectively:

[0126]

[0127] k M1 , k M2 , k M3 , Δk T1 , Δk T2For the calibration method and corresponding calibration coefficients when measuring vertical bending moment and torque simultaneously, during the actual test process, multiplying the obtained time-domain displacement change result by the above coefficients can obtain the vertical bending moment and torque values in the time domain.

[0128] The relative displacement change of the profile to be tested is measured by the laser displacement sensor 101. Only 3 - 5 measuring points need to be arranged, and the number of measuring points is approximately the same as the number of profiles. For torsional load measurement, only 6 - 10 measuring points need to be arranged, and the number of measuring points is approximately twice the number of profiles. The laser displacement sensor 101 and its supporting facilities can be reused, saving costs, with mature technology, few measuring points, and being convenient for installation and disassembly.

[0129] The displacement changes of different profiles can be measured by the laser displacement sensor 101, and the relationship between the displacement change and the bending moment and torque can be obtained through calibration. This method is convenient, fast, and can be disassembled and installed at any time, avoiding damage to the measuring device during the installation process of the measuring beam 201. Using the laser displacement sensor 101 for testing avoids the use of a large number of acquisition instruments and data transmission wires, can provide more weight margin for model inertia adjustment. At the same time, laser testing has good stability and high accuracy.

[0130] The above description is an explanation of the present invention, not a limitation of the invention. The scope defined by the present invention is referred to the claims, and within the protection scope of the present invention, any form of modification can be made.

Claims

1. A method for inverse measurement of bending moment in wave load model test, characterized in that, It includes the following steps: The first step: Determine the segmentation quantity and position of the ship model (200); The second step: Design the measuring beam (201); The third step: Install the laser bending moment measuring system (100) on the measuring beam (201); The fourth step: Calibrate the measuring beam (201). For the vertical bending moment measurement and the simultaneous measurement of vertical and torsion, different calibration methods are adopted. The calibration is carried out by gradually increasing the load and performing multiple calibrations; The fifth step: Based on the calibration data, obtain the conversion coefficient between displacement and load; The sixth step: Install the measuring beam (201) in the shell of the ship model (200); The seventh step: Complete the wave load model test according to the test conditions.

2. The moment inversion measurement method for wave load model test according to claim 1, wherein: The laser bending moment measuring system (100) includes a reflector (102) and a laser displacement sensor (101). The reflector (102) is connected to the measuring beam (201) through a fixing device (103), and the fixing device (103) and the reflector (102) are connected through a bracket (104); The laser displacement sensor (101) is fixed on the detachable horizontal beam at the non-measured section.

3. The moment inversion measurement method for wave load model test according to claim 2, wherein: The ship model (200) is divided into four segments, and the bending moments at three sections need to be measured. Five laser displacement sensors (101) are arranged on the detachable horizontal beam at the non-measured section, which are respectively the first laser displacement sensor (1011), the second laser displacement sensor (1012), the third laser displacement sensor (1013), the fourth laser displacement sensor (1014) and the fifth laser displacement sensor (1015) from one side to the other side. Reflectors corresponding to the first laser displacement sensor (1011), the second laser displacement sensor (1012), the third laser displacement sensor (1013), the fourth laser displacement sensor (1014) and the fifth laser displacement sensor (1015) are arranged on the measured sections, namely the first reflector (1021), the second reflector (1022), the third reflector (1023), the fourth reflector (1024) and the fifth reflector (1025). The third reflector (1023) is arranged on the middle measured section. The first laser displacement sensor (1011) and the second laser displacement sensor (1012) are arranged on one measured section, and the fourth laser displacement sensor (1014) and the fifth laser displacement sensor (1015) are arranged on the other measured section.

4. The method for inverse measurement of bending moment in wave load model test according to claim 3, wherein: The bending moment is measured by the first laser displacement sensor (1011), the third laser displacement sensor (1013), the fifth laser displacement sensor (1015) and the corresponding first reflector (1021), third reflector (1023), fifth reflector (1025).

5. The method for inverse measurement of bending moment in wave load model test according to claim 4, wherein: The bending moment and torque are measured by the first laser displacement sensor (1011), the second laser displacement sensor (1012), the third laser displacement sensor (1013), the fourth laser displacement sensor (1014), the fifth laser displacement sensor (1015) and the corresponding first reflector (1021), second reflector (1022), third reflector (1023), fourth reflector (1024), fifth reflector (1025).

6. The moment inversion measurement method for wave load model test according to claim 5, characterized in that: In the fourth step, the measuring beam (201) and the laser bending moment measuring system (100) are placed on the support structure. A weight (400) is hung on the measuring beam (201), and the weight (400) is placed on the weight tray (401). The weight tray (401) is connected to the measuring beam (201) through a hanging wire rope (402). The bending moment at the location of the maximum bending moment is: where m is the weight of the weight (400) in kg; g is the acceleration due to gravity in m / s 2 ; L5 and L4 are the distances from the position where the weight (400) is placed before loading to both ends, in m; The measuring profiles corresponding to the first reflector (1021) and the second reflector (1022) are Profile 1, the measuring profiles corresponding to the fourth reflector (1024) and the fifth reflector (1025) are Profile 2, and the measuring profile corresponding to the third reflector (1023) is Profile 3. The bending moment corresponding to Section 1 is: The bending moment corresponding to Section 2 is: The bending moment corresponding to Section III is: Wherein, L1 is the distance from the first reflector (1021) and the second reflector (1022) to the loading position of the weight (400) before loading, with the unit of m; L2 is the distance from the third reflector (1023) to the loading position of the weight (400) before loading, with the unit of m; L3 is the distance from the fourth reflector (1024) and the fifth reflector (1025) to the loading position of the weight (400) before loading, with the unit of m. Before loading, the distances from the laser displacement sensor (101) to the first reflector (1021) and the second reflector (1022) are D1, the distance from the laser displacement sensor (101) to the third reflector (1023) is D2, and the distances from the laser displacement sensor (101) to the fourth reflector (1024) and the fifth reflector (1025) are D3. After loading, due to the deformation of the structure, the distances from the laser displacement sensor (101) to the first reflector (1021) and the second reflector (1022) are D1′, the distance from the laser displacement sensor (101) to the third reflector (1023) is D2′, and the distances from the laser displacement sensor (101) to the fourth reflector (1024) and the fifth reflector (1025) are D3′. Due to the loading of the weight (400), displacement variables of ΔD1 = D1 - D1′, ΔD2 = D2 - D2′, and ΔD3 = D3 - D3′ are respectively generated at each reflector (102). The corresponding coefficients k1, k2, k3, k4, and k5 of the displacements and bending moments at the three corresponding positions are: k1 = k2 = M1 / ΔD1; k3 = M3 / ΔD2; k4 = k5 = M2 / ΔD3; k1, k2, k3, k4, and k5 are the calibration methods and corresponding calibration coefficients for only vertical bending moment measurement. During the actual test process, the obtained time-domain displacement change results are multiplied by k1, k2, k3, k4, and k5 to obtain the time-domain bending moment values.

7. The moment inversion measurement method for wave load model test according to claim 6, characterized in that: In the fourth step, for the coefficient calibration when simultaneously measuring the vertical bending moment and torque, one end of the measuring beam (201) is rigidly fixed, and the weight (400) is hung at the other end of the measuring beam (201). The bending moment at the maximum bending moment at the left end is: M = m × g × L4; where m is the weight of the weight (400) in kg; g is the acceleration due to gravity in m / s 2 ; L4 is the distance from the loading position of the weight (400) before loading to the fixed section in m; The displacement variable at the first reflector 1021 is: ΔD 1-1 = ΔD M1 + ΔD T1 ; The displacement variable at the second reflector 1022 is: ΔD 1-2 = ΔD M1 -ΔD T1 ; The displacement variable at the third reflector 1023 is: ΔD 3-3 = ΔD M3 ; The displacement variable at the 1024th position of the reflector four is: ΔD 2-4 = ΔD M2 + ΔD T2 ; The displacement variable at the fifth reflector 1025 is: ΔD 2-5 = ΔD M2 + ΔD T2 ; where, ΔD M1 , ΔD M2 , ΔD M3 are the displacement variables caused by bending at section 1, section 2 and section 3 respectively; ΔD T1 , ΔD T2 are the displacement variables caused by torque at section 1 and section 2 respectively; The bending moment corresponding to Section 1 is: The bending moment corresponding to Section 2 is: The bending moment corresponding to Section III is as follows: The torques corresponding to Profile 1 and Profile 2 are: M T1 = M T2 = m × g × T; Wherein, T is the distance from the position where the weight (400) is applied to the center of the end face of the measuring beam (201). Before loading, the distances from the laser displacement sensor (101) to the first reflector (1021), the second reflector (1022), the third reflector (1023), the fourth reflector (1024), and the fifth reflector (1025) are D1, D2, and D3 respectively. After loading, due to the deformation of the structure, the distance variables from the laser displacement sensor (101) to the first reflector (1021), the second reflector (1022), the third reflector (1023), the fourth reflector (1024), and the fifth reflector (1025) are ΔD 1-1 , ΔD 1-2 , ΔD 3-3 , ΔD 2-4 , ΔD 2-5 ; The corresponding coefficients k M1 , k M2 , k M3 for displacement and bending moment of Profile 1, Profile 2 and Profile 3, and the corresponding coefficients Δk T1 , Δk T2 are respectively: Multiplying the obtained time-domain displacement change result by the above coefficients can obtain the vertical bending moment and torque values in the time domain.

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