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CN-121997810-A - Method for rapidly forecasting water slamming force of three-dimensional structure based on slamming force decomposition

CN121997810ACN 121997810 ACN121997810 ACN 121997810ACN-121997810-A

Abstract

The invention discloses a rapid forecasting method for water slamming force of a three-dimensional structure, and relates to the technical field of fluid mechanics and data processing. According to the method, a three-dimensional structure digital model is built, mechanical data are acquired through CFD software multi-working-condition simulation, three types of coefficients related to immersion depth are extracted, a mapping model of body type characteristics and coefficients is built based on a deep neural network, and finally quick prediction of slamming force and pressure is achieved. According to the invention, the two-dimensional slamming force decomposition theory is promoted to be three-dimensional, the inclined track water entering scene is supported, meanwhile, slamming force and pressure calculation is covered, the corresponding relation between the body type and the coefficient is established through the data-driven mapping model, repeated iteration is not needed in the forecasting process, the method is suitable for various regular and irregular three-dimensional structures, and the applicability, accuracy and efficiency of forecasting are remarkably improved.

Inventors

  • SUN ZHE
  • MA YINGXU

Assignees

  • 大连理工大学
  • 中国船舶科学研究中心

Dates

Publication Date
20260508
Application Date
20251231

Claims (8)

  1. 1. The rapid water slamming force forecasting method for the three-dimensional structure based on slamming force decomposition is characterized by comprising the following steps of: Step 1, constructing a digital model of a target three-dimensional structure, and defining positive and negative judgment rules of the immersion depth, the movement speed and the acceleration of the model; Step2, carrying out multi-working condition simulation through computational fluid dynamics software, and collecting mechanical data of interaction between the three-dimensional structure and fluid under different motion states; step 3, extracting a speed term coefficient, an acceleration term coefficient and a gravity term coefficient related to the immersion depth according to a preset formula based on the collected mechanical data; Step 4, constructing three independent data mapping models, taking the body shape characteristics and draft of the three-dimensional structure as input data, taking the three types of coefficients extracted in the step 3 as output data respectively, and optimizing model parameters through training library data until the preset precision requirement is met; and 5, inputting the body type characteristics and a series of draft of the three-dimensional structure to be forecasted, obtaining a corresponding coefficient curve through a mapping model which is completed through training, and calculating slamming force and pressure of the structure in the water entering process by combining the fluid density and the gravity acceleration.
  2. 2. The method of claim 1, wherein the construction of the digital model in step 1 includes determining geometric dimensions, shape parameters and symmetry characteristics of the three-dimensional structure, and the positive and negative determination rules are that the immersion depth is constant positive, the acceleration during acceleration movement is positive, and the acceleration during deceleration movement is negative.
  3. 3. The method of claim 1, wherein the multi-operating simulation in step 2 includes three scenarios: closing the gravity of the fluid, and controlling the three-dimensional structure to do uniform vertical water inlet movement at a preset high speed; closing the gravity of the fluid, controlling the three-dimensional structure to do uniform variable speed vertical water inflow movement at a preset high initial speed, and enabling the absolute value of acceleration to be not larger than the absolute value of the initial speed during uniform deceleration movement; and opening the gravity of the fluid, setting the gravity acceleration, and controlling the three-dimensional structure to do uniform vertical water inlet movement at a preset low speed.
  4. 4. The method of claim 1, wherein the mechanical data in step 3 includes curve data of vertical slamming force, horizontal slamming force and fluid pressure as a function of immersion depth, and the predetermined formula is a coefficient extracted by an operational relationship between the mechanical data and corresponding motion parameters and fluid physical parameters.
  5. 5. The method according to claim 1, wherein the body type characteristics in step 4 include control point dimensionless vertical height of the three-dimensional structure, curvature parameters, and the preset accuracy requirement is that the model loss function value is less than 1e-5.
  6. 6. The method of claim 1, wherein the slamming force in step 5 comprises a vertical slamming force and a horizontal slamming force calculated by summing the corresponding coefficients with the products of fluid density, structure velocity square, acceleration and gravitational acceleration, respectively.
  7. 7. The method of claim 1, wherein the three-dimensional structure comprises regular-shape objects and irregular-shape objects, and the water-in motion comprises vertical-track water-in and inclined-track water-in.
  8. 8. The method of claim 1, wherein the data mapping model in step 4 is a deep neural network model, the model training process includes data partitioning, iterative optimization and accuracy verification, and the training library data is CFD simulation verification data of three-dimensional structures of different sizes.

Description

Method for rapidly forecasting water slamming force of three-dimensional structure based on slamming force decomposition Technical Field The invention relates to the technical field of fluid mechanics and data processing, in particular to a rapid forecasting method for water slamming force of a three-dimensional structure based on slamming force decomposition. Background Slamming force forecasting in the water entering process of a three-dimensional structure is a key link of structural design and safety evaluation in the fields of ship engineering, ocean engineering, aerospace and the like. Slamming is a transient impact force generated by the rapid interaction of a structure with a fluid, the magnitude and law of change of which directly affect the strength design and service life of the structure. In the prior art, the slamming force related calculation method has a plurality of limitations that firstly, most technologies are only suitable for two-dimensional or quasi-two-dimensional structures, a theoretical system and a calculation model of the slamming force related calculation method are difficult to directly migrate to the three-dimensional structures, the prediction requirement of a complex three-dimensional structure in actual engineering cannot be met, secondly, the existing model is limited to a vertical track water entry scene, inclined movement often exists in the water entry process of an actual ship, marine equipment and the like, so that the deviation between the prediction result and the actual situation of the existing method is large, thirdly, the existing technology only carries out decomposition calculation on slamming force, does not cover the pressure prediction of fluid on the structures in the water entry process, the stress state of the structures cannot be comprehensively reflected, fourthly, the existing technology does not establish the clear corresponding relation between the structural object type characteristics and slamming force coefficients, and the complex numerical simulation or test needs to be repeatedly carried out on structures with different shapes, and the prediction efficiency is low. Therefore, developing a rapid forecasting method which is suitable for three-dimensional structures, supports various water entering postures, gives attention to slamming force and pressure forecasting and has high efficiency is a technical problem to be solved in the field. Disclosure of Invention According to the technical problems, the method for rapidly forecasting the slamming force of the water of the three-dimensional structure based on slamming force decomposition is provided. According to the invention, the two-dimensional slamming force decomposition theory is promoted to be three-dimensional, the inclined track water entering scene is supported, meanwhile, slamming force and pressure calculation is covered, the corresponding relation between the body type and the coefficient is established through the data-driven mapping model, repeated iteration is not needed in the forecasting process, the method is suitable for various regular and irregular three-dimensional structures, and the applicability, accuracy and efficiency of forecasting are remarkably improved. The invention adopts the following technical means: a three-dimensional structure water slamming force quick forecasting method based on slamming force decomposition comprises the following steps: Step 1, constructing a digital model of a target three-dimensional structure, and defining positive and negative judgment rules of the immersion depth, the movement speed and the acceleration of the model; Step2, carrying out multi-working condition simulation through computational fluid dynamics software, and collecting mechanical data of interaction between the three-dimensional structure and fluid under different motion states; step 3, extracting a speed term coefficient, an acceleration term coefficient and a gravity term coefficient related to the immersion depth according to a preset formula based on the collected mechanical data; Step 4, constructing three independent data mapping models, taking the body shape characteristics and draft of the three-dimensional structure as input data, taking the three types of coefficients extracted in the step 3 as output data respectively, and optimizing model parameters through training library data until the preset precision requirement is met; and 5, inputting the body type characteristics and a series of draft of the three-dimensional structure to be forecasted, obtaining a corresponding coefficient curve through a mapping model which is completed through training, and calculating slamming force and pressure of the structure in the water entering process by combining the fluid density and the gravity acceleration. Further, the construction of the digital model in the step 1 comprises the steps of determining the geometric dimension, the shape parameter and the symmetry character