Ship riding wave stability failure determinacy balance evaluation method

Abstract

The invention relates to a ship riding wave stability failure determinacy balance evaluation method, and belongs to the technical field of ships. According to the method, a'speed increasing 'phenomenon is used for replacing'wave riding' to serve as a judgment core, the instantaneous wave speed is accurately calculated and the speed increasing duration time proportion is counted in combination with a multi-degree-of-freedom time domain simulation and wave surface tracking method, and is compared with a preset threshold value, so that stability balance evaluation is efficiently and accurately completed, and the calculation efficiency and the engineering applicability are greatly improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of ship technology, in particular to a ship riding stability failure certainty criterion evaluation method. BACKGROUND

[0002] With the development of ship hydrodynamics and stability evaluation technology, a riding stability failure evaluation method based on direct numerical simulation appears; the method realizes accurate estimation of ship stability failure probability by modeling the response of ship motion in waves in detail and counting the number of riding stability failure in a direct counting manner, and its characteristics are that it can fully consider the influence of various physical factors in actual sea conditions, and the evaluation result has high reliability.

[0003] In related technologies, long-time irregular wave numerical simulation is usually used to capture riding stability failure events, and high-performance computing resources are used to perform large-scale simulation to obtain sufficient failure sample number for probability calculation.

[0004] However, the above direct simulation evaluation method has the problem that the calculation efficiency and accuracy are difficult to balance:

[0005] Since riding stability failure is a small probability event, it is difficult to obtain sufficient failure times through simulation within a reasonable time; at the same time, the high-fidelity numerical model itself has high calculation cost and long time consumption, which further limits the engineering applicability of the method.

[0006] Therefore, it is urgent to develop a more efficient and stable riding stability evaluation method. SUMMARY

[0007] Therefore, it is necessary to provide a ship riding stability failure certainty criterion evaluation method to solve the above problems, so as to ensure the calculation accuracy of the direct stability evaluation of riding stability failure and greatly reduce the calculation amount and improve the evaluation efficiency.

[0008] A ship riding stability failure certainty criterion evaluation method, characterized in that it comprises the following steps:

[0009] Step 1: Determine the determination method of riding stability failure in irregular waves, replace the "riding" phenomenon with the "speed increase" phenomenon, and determine the occurrence of the "speed increase" phenomenon by the instantaneous wave speed of the sea wave, the instantaneous speed of the ship and the nominal speed of the ship;

[0010] Step 2: Determine the design scene working condition, including determining the ship navigation parameters according to the ship loading conditions and navigation requirements, and determining the sea state parameters according to the target sea area;

[0011] Step three, based on the time domain calculation model of riding motion, sequentially execute the ship motion numerical simulation under each design scenario working condition, the total simulation time is not less than 15 hours, which can be carried out in segments, and each segment simulation ends with the set maximum duration;

[0012] Step four, the wave surface tracking method is used to calculate the instantaneous wave speed of the sea surface near the ship corresponding to different random seed numbers under each design scenario working condition;

[0013] Step five, according to the speed-up phenomenon judgment condition, the proportion of the speed-up duration in the total simulation time in each working condition is calculated, and the average value of the speed-up duration proportion corresponding to different seed numbers in each working condition is calculated;

[0014] Step six, according to the preset threshold, determine whether the ship passes the deterministic threshold evaluation of riding stability failure: if the average value in all working conditions is less than the threshold, it passes the evaluation; otherwise, it does not pass.

[0015] In one embodiment, the judgment method of the "speed-up" phenomenon in step one is:

[0016] When the instantaneous speed component of the ship in the wave propagation direction exceeds the instantaneous wave speed, it is determined to start speed-up;

[0017] When the instantaneous speed component is lower than the nominal speed, it is determined that the speed-up ends.

[0018] In one embodiment, the riding motion time domain calculation model in step three includes at least the motion equations of four degrees of freedom, i.e. surge, sway, roll and yaw.

[0019] In one embodiment, the ship riding motion time domain calculation model is:

[0020]

[0021] Wherein, m, I xx ,I zz respectively represent the mass, roll inertia moment and yaw inertia moment of the ship;

[0022] A ij represents the contribution of the i-th degree of freedom to the added mass of the j-th degree of freedom;

[0023] represents the speed of the i-th degree of freedom of the ship; represents the acceleration of the ship in the i-th degree of freedom;

[0024] F i H represents the component of the hull force in the i-th degree of freedom;

[0025] F iR represents the component of the rudder force in the i-th degree of freedom;

[0026] F1 P represents the component of the propeller thrust in the i-th degree of freedom;

[0027] F i FK represents the component of the incident wave force in the i-th degree of freedom;

[0028] F i Diff represents the component of the diffracted wave force in the i-th degree of freedom;

[0029] F i Res represents the component of the restoring force in the i-th degree of freedom;

[0030] The parameters i, j ∈ {1, 2, 3, 4, 5, 6}, and the first to sixth degrees of freedom respectively represent the surge, sway, heave, roll, pitch and yaw directions;

[0031] g is the acceleration of gravity;

[0032] μ is the correction coefficient of the surge wave force diffraction effect.

[0033] In one of the embodiments, the wave surface tracking method in step four includes:

[0034] generating the wave surface shape near the ship at the current time and the next time;

[0035] determining the extreme points of the wave surface at the two times, dividing the intervals and selecting the intersection points;

[0036] performing equal-height interpolation on each interval to obtain two groups of interpolation points;

[0037] calculating the displacement change of each interpolation point divided by the time interval to obtain the instantaneous wave speed at each interpolation point;

[0038] selecting the maximum value of the instantaneous wave speed in the contact area of the ship within the ship length as the instantaneous wave speed for determining the start of the "speed increase".

[0039] In one of the embodiments, the statistical formula of the average value P of the speed increase duration ratio in step five is as follows:

[0040]

[0041] wherein m is the total number of sea state random seeds under the design scenario working condition;

[0042] i is the random seed number indicating the irregular sea state;

[0043] p iThe ratio of the duration of the speed increase to the total simulation duration for the i-th seed number;

[0044] j is an index indicating the speed increase of the ship in the numerical simulation for each seed number;

[0045] n i The total number of speed increases in the numerical simulation for the i-th seed number;

[0046] t ij The duration of the j-th speed increase of the ship in the numerical simulation for the i-th seed number;

[0047] t total The total simulation duration for each seed number.

[0048] In one embodiment, the determination of the sea state parameters in step two includes:

[0049] Determining the spectral peak period of the target sea state according to the ship length;

[0050] Determining the significant wave height according to the relationship between the sea state probability and the significant wave height and the wave period of the target sea area;

[0051] If there is no relevant data, the sea state data of the North Atlantic is used and linear interpolation is performed.

[0052] In one embodiment, the ship navigation parameters in step two include the following:

[0053] In one embodiment, the total simulation time in step three is divided into five segments, and each segment has a simulation duration of 3 hours.

[0054] In one embodiment, the threshold value in step six is a preset percentage value for judging the risk degree of the duration of the speed increase.

[0055] The above method for evaluating the stability failure determination criterion of the ship riding on the wave completely solves the engineering bottleneck of the probability evaluation of the small probability event, and the simulation time required is greatly shortened.

[0056] The present application also has the following advantages:

[0057] The application proposes accurate "speed-up" determination conditions, which have clear physical meaning (the ship is accelerated by waves and the speed is higher than the nominal speed), are easy to automatically identify and count in time domain simulation; the "failure" problem which is difficult to directly and quickly determine is converted into the "speed-up duration ratio" problem which is easy to accurately quantify and programmed; in addition, by introducing multiple random seeds and taking the average P, the randomness of single random simulation is effectively smoothed, making the evaluation result more representative;

[0058] The application is parallel and independent calculation, and the simulation of different seeds is independent of each other, which is suitable for parallel calculation on a high-performance computing cluster, further shortening the actual time consumption;

[0059] The application clearly requires at least a four-degree-of-freedom (surge-sway-rolling- yaw) model, rather than the single-degree-of-freedom simplified model mentioned in the prior art, which fully considers the rolling and yaw coupling effect which is crucial for riding waves, ensuring the accuracy of the motion prediction;

[0060] The application uses the wave surface tracking method to calculate the instantaneous wave speed, which can accurately reflect the true propagation speed of each wave surface in irregular waves, so that the triggering of the "speed-up" criterion is more accurate and reliable;

[0061] The application is not a general ocean exploration, but is based on the design scenario working condition; the working condition is determined according to the actual loading of the ship, the speed and the statistical sea conditions of the target sea area, and has strong engineering guidance significance. BRIEF DESCRIPTION OF DRAWINGS

[0062] Figure 1 Flow chart for ship riding stability failure deterministic criterion evaluation method.

[0063] Figure 2 Schematic diagram for speed-up determination.

[0064] Figure 3 Schematic diagram of wave surface tracking method.

[0065] Figure 4 Schematic diagram of "speed-up" phenomenon duration statistics. DETAILED DESCRIPTION

[0066] In order to make the above-mentioned purposes, features and advantages of the application more obvious and easy to understand, the specific embodiments of the application will be described in detail below with reference to the accompanying drawings. In the following description, a large number of specific details are set forth in order to facilitate a full understanding of the application. However, the application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without departing from the spirit of the application, so the application is not limited by the specific embodiments disclosed below.

[0067] In the description of the application, it should be understood that, if there are these terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like, these terms indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the purpose of facilitating the description of the application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the application.

[0068] In addition, if there are these terms "first", "second", these terms are only for the purpose of description, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first", "second" can explicitly or implicitly include at least one of the features. In the description of the application, if the term "multiple" appears, the meaning of "multiple" is at least two, such as two, three, etc., unless otherwise explicitly specified and limited.

[0069] In this application, unless otherwise explicitly specified and limited, if there are terms such as "mounting", "connecting", "connecting", "fixing" and the like, these terms should be broadly understood. For example, it can be fixedly connected, or it can be detachably connected, or it can be integrated; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the internal communication of two elements or the interaction relationship between two elements, unless otherwise explicitly limited. For those skilled in the art, the specific meaning of the above terms in this application can be understood according to the specific circumstances.

[0070] In this application, unless otherwise explicitly specified and limited, if there are similar descriptions such as "first feature on or under second feature", the meaning can be that the first and second features are in direct contact, or the first and second features are indirectly in contact through an intermediate medium. Moreover, the first feature "above", "above" and "above" of the second feature can be that the first feature is directly above or obliquely above the second feature, or only indicates that the horizontal height of the first feature is higher than that of the second feature. The first feature "below", "below" and "below" of the second feature can be that the first feature is directly below or obliquely below the second feature, or only indicates that the horizontal height of the first feature is less than that of the second feature.

[0071] It is to be noted that when an element is referred to as being "on" or "connected to" another element, it can be directly on the other element or intervening elements can be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements can be present. As used herein the terms "vertical", "horizontal", "up", "down", "left", "right", and the like as well as similar terms, refer to the orientation of the apparatus as shown in the figures and are for illustrative purposes only and are not meant to be limiting.

[0072] Referring to Figure 1 , Figure 1 A flowchart of a ship riding stability failure determination evaluation method in an embodiment of the present application is shown. The ship riding stability failure determination evaluation method provided in an embodiment of the present application includes the following steps:

[0073] Step one, determine the ship riding stability failure determination method in irregular waves:

[0074] The "speed increase" phenomenon in irregular waves is used to replace the "riding" phenomenon in irregular waves, and the occurrence of the "speed increase" phenomenon is determined by the instantaneous wave speed, the instantaneous ship speed and the nominal ship speed.

[0075] Specifically, please refer to Figure 2 For irregular waves, the riding equilibrium condition can only be considered in an approximate sense because the wave field changes continuously in time and space, and can only be considered in the case where the wave field near the ship changes very slowly. Therefore, the "speed increase" phenomenon of the ship sailing at a speed higher than its rated speed for a long time is introduced, and the instability determination of the "speed increase" phenomenon in irregular waves is discussed instead of the instability determination of the "riding" phenomenon in irregular waves. The "speed increase" phenomenon determination method: when the instantaneous ship speed exceeds the instantaneous wave speed, it is considered that the ship starts to sail at a speed increase; when the instantaneous ship speed is lower than the nominal ship speed, it is considered that the speed increase of the ship ends. The threshold of the up-crossing point of the instantaneous ship speed is the instantaneous wave speed, and the threshold of the down-crossing point is the nominal ship speed.

[0076]

[0077] In the formula, uξ is the instantaneous speed component of the ship in the wave propagation direction;

[0078] c w is the instantaneous wave speed;

[0079] u nominal is the nominal ship speed.

[0080] Step two, determine the sailing parameters and sea state parameters of the ship under the design scenario;

[0081] The design scenario is set according to the actual sailing condition of the ship, and the most dangerous condition that can be encountered in the ship sailing is set as the design scenario.

[0082] Specifically, the ship sailing parameters are determined according to the ship loading conditions and sailing requirements, the speed-up phenomenon is a loss of stability phenomenon that occurs when the ship sails at high speed in the following wave or the tail inclined wave, and the ship sailing parameters can be selected as the following wave and the maximum service speed.

[0083] The sea state parameters are determined according to the target sea area. First, the target sea state period in which the ship is prone to riding waves is determined by the length of the ship, and then the significant wave height of the target sea state is obtained by the relationship between the sea state occurrence probability of the target sea area and the significant wave height and the wave period, so as to determine the design scenario working condition that meets the requirements.

[0084] When the ship sails at high speed in the steep wave with a wavelength comparable to or greater than the length of the ship, the ship is easily captured by the wave and speeds up, so the regular wave period corresponding to the wavelength-to-length ratio λ / L in the range of 1.0 to 1.5 is selected as the spectral peak period Tp of the target sea state, and the interval Δλ / L can be taken as 0.1.

[0085] For the case where the relationship between the sea state occurrence probability of the target sea area and the significant wave height and the wave period is lacking, the North Atlantic sea area data can be selected, for example, the sea state probability density of the North Atlantic sea area infinite navigation area is 7·10 -5 (m·s) -1 The relationship between the significant wave height (Hs) and the average zero-crossing period (Tz) is shown in Table 1.

[0086] Table 1

[0087] Tz(s) 4.5 5.5 6.5 7.5 8.5 9.5 10.5 11.5 12.5 13.5 14.5 15.5 Hs(m) 2.0 4.4 6.9 9.1 10.9 12.1 12.8 13.1 13.0 12.5 11.3 9.0

[0088] The spectral peak period Tp of the determined target sea state is converted into the average zero-crossing period Tz, and the corresponding significant wave height Hs can be obtained by linear interpolation according to the above table.

[0089] Step three, based on the time domain calculation model of the riding wave motion, the numerical simulation is sequentially performed according to the determined working condition. The ship motion numerical simulation under different seed numbers of each design scenario working condition is carried out, and the numerical simulation of each seed number is ended when the set maximum duration is reached;

[0090] The total simulation time of the ship motion numerical simulation under each working condition is at least 15 hours, and the motion numerical simulation can be divided into several partial simulation;

[0091] The motion simulation results corresponding to different seed numbers under each working condition are independent of each other;

[0092] Five numerical simulations are carried out under each working condition of the present application, each numerical simulation is 3 hours, and the total simulation time is 15 hours.

[0093] In order to accurately predict the stability failure of a ship in a wave, a ship motion time-domain calculation model with four degrees of freedom, i.e., surge, sway, heave, roll and yaw, is adopted, and the ship motion time-domain calculation model is as follows:

[0094]

[0095] wherein m, I xx ,I zz respectively represent the mass of the ship, the roll inertia moment and the yaw inertia moment;

[0096] A ij represents the contribution of the i-th degree of freedom to the added mass of the j-th degree of freedom;

[0097] represents the velocity of the i-th degree of freedom of the ship; represents the acceleration of the ship in the i-th degree of freedom;

[0098] F i H represents the component of the hull force in the i-th degree of freedom;

[0099] F i R represents the component of the rudder force in the i-th degree of freedom;

[0100] F1 P represents the component of the propeller thrust in the i-th degree of freedom;

[0101] F i FK represents the component of the incident wave force in the i-th degree of freedom;

[0102] F i Diff represents the component of the diffracted wave force in the i-th degree of freedom;

[0103] F i Res represents the component of the restoring force in the i-th degree of freedom;

[0104] parameters i, j ∈ {1, 2, 3, 4, 5, 6}, the first to sixth degrees of freedom respectively represent the surge, sway, heave, roll, pitch and yaw directions;

[0105] g is the gravitational acceleration;

[0106] μ is the correction coefficient of the surge wave force diffraction effect.

[0107] Step four, the wave face tracking method is adopted to calculate the instantaneous wave speed of the sea surface near the ship under different seed numbers of each design scenario, and the calculation of each seed number is ended when the set maximum duration is reached.

[0108] Wave face tracking method, namely selecting feature points on the irregular wave surface near the ship, tracking the changes of these feature points with time and space, and then obtaining the instantaneous wave speed of the irregular wave surface. This method can stably and comprehensively calculate the instantaneous speed of the entire wave profile.

[0109] Further, the wave face tracking method schematic diagram is shown in Figure 3 The specific method of calculating the instantaneous wave speed by the wave face tracking method is as follows:

[0110] Using the wave surface equation of random waves, tracking the wave surface near the ship, combining the current sailing position of the ship, generating the wave surface shape near the ship at the current time t0 and the wave surface shape at the next time t0+Δt;

[0111] Determine the extreme points of the wave surface shapes at the two times, and divide the wave surface shape into multiple intervals based on adjacent extreme points. The end point of each interval is the smaller of the two adjacent time wave surface maximum value and the larger of the minimum value, that is, the point where the two wave surface shape interval longitudinal coordinates intersect.

[0112] Respectively, each interval is subjected to equal height interpolation to obtain two sets of interpolation point sets. The longitudinal coordinates of the two sets of interpolation points are denoted as ξ 11 ,ξ 12 …ξ 1n and ξ 21 ,ξ 22 …ξ 2n ;

[0113] Calculate the displacement change Δξ i of each interpolation point =ξ 1i -ξ 2i , and divide by the time interval Δt, that is, the instantaneous wave speed c i at the position of each interpolation point =Δξ i / Δt.

[0114] In the ship length range, the maximum value c max of the instantaneous wave speed in the region in contact with the ship is selected as the threshold for judging the "speed increase" of the ship, that is, the instantaneous wave speed of the irregular wave near the center of gravity of the ship at time t.

[0115] Step five, speed increase duration ratio statistics.

[0116] The "speed increase" phenomenon duration statistics schematic diagram is shown in Figure 4 .

[0117] According to the speed increase phenomenon judgment condition, the ratio of the speed increase duration to the total ship movement time in each voyage under each seed number is calculated under each working condition, and the average value of the speed increase duration ratio of the ship under different seed numbers in each working condition is taken.

[0118] It is not good to measure whether the ship is dangerous only by whether the "speed-up" phenomenon occurs, because the duration of each "speed-up" in irregular waves also changes over time, and a short "speed-up" cannot explain that the ship is dangerous. Therefore, the "ratio of speed-up duration to total simulation duration" is used to measure it.

[0119] The statistical formula of the average value P of the ratio of speed-up duration to total simulation duration of different seeds in a design scenario is as follows:

[0120]

[0121] Wherein, m is the total number of random seeds of sea state in a certain design scenario;

[0122] i is a random seed number indicating irregular sea state;

[0123] p i is the ratio of speed-up duration to total simulation duration under the i-th seed number;

[0124] j is a ship speed-up phenomenon in numerical simulation under each seed number;

[0125] n i is the total number of speed-ups in numerical simulation under the i-th seed number;

[0126] t ij is the duration of the j-th speed-up of the ship in numerical simulation under the i-th seed number;

[0127] t total is the total numerical simulation duration under each seed number.

[0128] Step six, determine whether the ship passes the stability criterion evaluation of riding wave stability failure according to the criterion threshold.

[0129] If the ratio of speed-up duration under all design conditions is less than the criterion threshold, it is considered that the ship can pass the riding wave stability criterion evaluation under the loading condition; if the ratio of speed-up duration under one design condition is greater than the criterion threshold, it is considered that the ship cannot pass the riding wave stability criterion evaluation under the loading condition.

[0130] In summary, the application replaces "riding wave" with "speed-up" as the core of judgment, combines multi-degree-of-freedom time-domain simulation with wave surface tracking method to accurately calculate instantaneous wave speed, and compares the ratio of speed-up duration with the preset threshold, thereby efficiently and accurately completing stability criterion evaluation, and greatly improving the calculation efficiency and engineering applicability.

[0131] Any combination of the technical features in the above-described embodiments can be made, and for the sake of brevity, not all possible combinations are described, however, it is to be understood that the application embraces all such possible combinations.

[0132] The above-described embodiments only express several implementation manners of the present application, and the description is relatively specific and detailed, but it should not be understood as a limitation on the patent scope of the application. It should be pointed out that for ordinary skilled persons in the art, some modifications and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the patent protection scope of the present application should be subject to the appended claims.

Claims

1. A method of evaluating a ship's wave-riding stability failure certainty criterion, characterized by, The method comprises the following steps: Step 1: determining a judgment method for irregular wave riding stability failure, replacing the riding phenomenon with the "speed increase" phenomenon, and determining the occurrence of the "speed increase" phenomenon by the instantaneous wave speed, the instantaneous ship speed and the nominal speed of the sea wave; Step 2: determining the design scenario working conditions, including determining the ship navigation parameters according to the ship loading conditions and navigation requirements, and determining the sea state parameters according to the target sea area; Step 3: based on the riding motion time domain calculation model, sequentially performing ship motion numerical simulation under each design scenario working condition, the total simulation time is not less than 15 hours, which can be divided into segments, and each segment simulation ends with a set maximum duration; Step 4: using the wave surface tracking method to calculate the instantaneous wave speed of the sea surface near the ship corresponding to different random seed numbers under each design scenario working condition; Step 5: according to the speed increase phenomenon judgment condition, the proportion of the speed increase duration in the total simulation time under each working condition is counted, and the average value of the speed increase duration proportion corresponding to different seed numbers under each working condition is calculated; Step 6: according to the preset threshold, determining whether the ship passes the certainty threshold evaluation of riding stability failure: if the average value under all working conditions is less than the threshold, it passes the evaluation; otherwise, it does not pass.

2. A method of assessing a ship ride quality failure certainty measure according to claim 1, characterised in that, The judgment method of the "speed increase" phenomenon in step 1 is: When the instantaneous speed component of the ship in the wave propagation direction exceeds the instantaneous wave speed, it is determined that the speed increase starts; When the instantaneous speed component is lower than the nominal speed, it is determined that the speed increase ends.

3. A method of evaluating a ship ride quality failure certainty measure according to claim 1, characterized in that, The riding motion time domain calculation model in step 3 at least includes the motion equations of four degrees of freedom of surge, sway, roll and yaw.

4. A method of assessing a ship ride quality failure certainty measure according to claim 3, characterised in that, The ship riding motion time domain calculation model is: where m, Ix, Iy xx ,I zz respectively denote the ship mass, roll inertia moment and yaw inertia moment; A ij represents the contribution of the i-th degree of freedom to the added mass of the j-th degree of freedom; V, represents the velocity of the ship in the i-th degree of freedom; a, represents the acceleration of the ship in the i-th degree of freedom; F i H Xi represents the component of the hull force in the i-th degree of freedom; F i R represents the component of the rudder force in the i-th degree of freedom; F1 P represents the component of the propeller thrust in the i-th degree of freedom; F i FK denotes the component of the incident wave force in the i-th degree of freedom; F i Diff denotes the component of the diffracted wave force in the i-th degree of freedom; F i Res denotes the component of the restoring force in the i-th degree of freedom; Parameters i, j ∈ {1, 2, 3, 4, 5, 6}, the first to sixth degrees of freedom respectively represent surge, sway, heave, roll, pitch and yaw directions; g is the acceleration of gravity; μ is the diffraction effect correction coefficient of the longitudinal wave force.

5. The ship ride quality failure certainty metric evaluation method of claim 1, wherein, The wave surface tracking method in step 4 includes: Generating the wave surface shape near the ship at the current time and the next time; Determine the extreme points of the wave surface at the two times, divide the intervals and select the intersection points; Interpolating each interval at the same height to obtain two groups of interpolation points; Calculate the displacement change of each interpolation point divided by the time interval to obtain the instantaneous wave speed at each interpolation point; Select the maximum value of the instantaneous wave speed in the contact area of the ship within the ship length as the instantaneous wave speed for determining the start of the "speed increase".

6. The ship ride quality failure certainty metric evaluation method of claim 1, wherein, The statistical formula of the average value P of the speed increase duration proportion in step 5 is as follows: Wherein, m is the total number of sea state random seeds under the design scenario working condition; i indicates the random seed number of irregular sea state; p i is the ratio of the duration of the speed-up for the i-th seed to the total simulation duration. j indicates the ship speed increase phenomenon in numerical simulation under each seed number; n i N(i) is the total number of increments for the i-th seed number. t ij tj is the time length of the jth speed increase of the ship in the numerical simulation under the ith number of seeds; t total Simulate the total number of values for each seed number for the duration.

7. The ship ride quality failure certainty metric evaluation method of claim 1, wherein, The determination of the sea state parameters in step 2 includes: Determine the spectral peak period of the target sea state according to the ship length; According to the relationship between the sea state probability and the significant wave height and wave period of the target sea area, the significant wave height is determined; If there is no relevant data, the sea state data of the North Atlantic Ocean is used and linear interpolation is performed.

8. The ship ride quality failure certainty metric evaluation method of claim 1, wherein, The ship navigation parameters in step 2 include following the wave and the maximum service speed.

9. The ship ride quality failure certainty metric evaluation method of claim 1, wherein, The total simulation time in step 3 is divided into 5 segments, and each segment simulation time is 3 hours.

10. A method of evaluating a ship ride quality failure certainty measure according to claim 1, characterized in that, The criterion threshold in the step six is a preset percentage value for judging the dangerous degree of the acceleration duration. The criterion threshold in the step six is a preset percentage value for judging the dangerous degree of the acceleration duration.

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