Vibration reduction and impact resistance integrated structure optimization method suitable for ship base

Abstract

The invention discloses a vibration reduction and impact resistance integrated structure optimization method suitable for a ship base, and the method comprises the steps: carrying out the parameterization processing of a tensile section of a plate frame type three-dimensional negative poisson ratio honeycomb base structure, and obtaining all design parameters of the base; selecting two variables as design variables, and establishing a base model based on a parametric modeling method; simulating the base model by using a steady-state excitation simulation method to obtain an acceleration vibration level fall, simulating the base model by using a transient impact simulation method to obtain an impact amplification coefficient, and evaluating the vibration reduction performance and the impact resistance of the base respectively; a response surface method is adopted to fit mathematical models of the two design variables for the vibration reduction performance and the shock resistance; two design variables are coded into an individual gene character string, an optimization target is selected, and a genetic algorithm is used for optimization. According to the method, the vibration reduction performance and the shock resistance of the base can be comprehensively considered, and the accuracy and the reliability of an optimization result are ensured by combining a genetic algorithm and finite element calculation.

Description

Technical Field

[0001] The invention belongs to the technical field of structural optimization of ship foundations, and in particular relates to a vibration reduction and impact resistance integrated structural optimization method suitable for ship foundations. Background Art

[0002] During the working process, ships are often subjected to various internal and external excitation loads, which cause various vibration problems. With the increasing requirements for speed of modern ships, the rotation speed and power of ship equipment such as main engines are getting higher and higher, and the vibration problem of ships has received more and more attention. At the same time, since ships undertake various combat missions, they are inevitably threatened by explosion shocks in combat. The shocks caused by explosions may cause damage to ship equipment, especially damage to the power and power systems, which will directly cause the ship to lose its combat capability. The base structure is the main carrier of the vibration source of various mechanical equipment on the ship, and it is the main channel for the vibration of the equipment to be transmitted to the ship structure. Depending on the different types of equipment carried, the base form will also be different. How to reasonably design the structural form to enhance the vibration isolation ability of the base under complex excitation of the equipment while ensuring the normal operation of the equipment is one of the effective ways to reduce the level of ship radiated noise.

[0003] Analysis of the design of vibration isolation structures on existing ships shows that they mainly meet the following two performance requirements: first, they should have the ability to isolate or absorb external energy, and second, they should have a certain stiffness and strength to play a supporting role, emphasizing the combination of structural bearing capacity and special functionality. In recent years, with the in-depth research and rapid development of process manufacturing, the performance requirements for ship foundations have also increased. On the basis of better vibration isolation performance, whether it can take into account the impact resistance to reduce the probability of equipment damage has become the focus of research. Based on this, the design of ship foundation structures with integrated vibration reduction and impact resistance and parameter optimization have become an urgent need.

[0004] In current research, attempts are made to design the base using various new metamaterials, among which porous structures and negative Poisson's ratio structures have been proven to have excellent vibration isolation performance, and can achieve both load-bearing performance and vibration reduction performance through reasonable structural and parameter design. However, the current structural design of new bases is often carried out for a single goal and lacks parameter optimization. Summary of the invention

[0005] In order to meet the demand of the base vibration isolation structure on the ship to take into account the impact resistance performance on the basis of better vibration isolation performance, the base structure design of various new metamaterials has received extensive attention. However, the current related designs are still mainly carried out for a single goal and lack parameter optimization. The present invention provides a vibration reduction and impact resistance integrated structure optimization method suitable for the ship base. Based on the parametric modeling idea, the finite element model establishment and parameter setting steps of the negative Poisson's ratio honeycomb base structure are scripted, the multi-objective optimization model is simplified by combining the response surface method, and the genetic algorithm main program is written using MATLAB software. The ABAQUS finite element software is jointly mobilized to calculate and solve the evaluation parameters such as the base acceleration level drop under steady-state excitation and the base impact amplification factor under the impact of the three-fold impact spectrum, and the structural design parameters are optimized generation by generation to achieve the optimization of the design parameters of the ship base structure with integrated vibration reduction and impact resistance.

[0006] In order to achieve the above technical objectives, the present invention adopts the following technical solutions:

[0007] According to a first aspect of the present invention, there is provided a vibration reduction and shock resistance integrated structure optimization method applicable to a ship foundation, the method comprising:

[0008] The tensile section of the plate-frame three-dimensional negative Poisson's ratio honeycomb base structure is parameterized to obtain the design parameters of the base.

[0009] Select two design parameters from the design parameters of the base as design variables, and take the remaining design parameters as constants, and establish a base model based on a parametric modeling method;

[0010] The base model is simulated by using a steady-state excitation simulation method to obtain the acceleration level drop, and the base model is simulated by using a transient impact simulation method to obtain the impact amplification factor; wherein, the acceleration level drop is used to evaluate the vibration reduction performance of the base, and the impact amplification factor is used to evaluate the impact resistance performance of the base;

[0011] The response surface method is used to fit the mathematical model of the two design variables on the vibration reduction performance and the impact resistance performance, and the response surface model of the acceleration level drop and the impact amplification factor is obtained.

[0012] Encode the two design variables into an individual gene string;

[0013] Select vibration reduction performance or impact resistance as the main optimization target, and the other as the secondary optimization target; the main optimization target is obtained by model simulation and used as the individual fitness; the secondary optimization target is obtained by the response surface model, and the threshold of the secondary optimization target is set as a constraint condition;

[0014] Genetic algorithm is used to optimize two design variables.

[0015] In the above scheme, the base model is established, including:

[0016] The stretched section is stretched to obtain a stretched entity, the stretched entity is rotated 90° and combined to obtain a unit cell structure model, and the unit cell structure model is arranged and combined in three directions of X, Y, and Z to obtain a base model.

[0017] In the above scheme, the design parameters of the base include: main side length L1, hypotenuse length L2, extended support length L3, cell angle α and honeycomb thickness T H .

[0018] In the above scheme, the base model is simulated by using the steady-state excitation simulation method to obtain the acceleration level drop, including:

[0019] The steady-state excitation simulation method uses the modal superposition method to perform harmonic response analysis, extracts the acceleration data at each evaluation point in the base model, and obtains the vibration level through calculation and processing;

[0020] The calculation method of acceleration level difference is as follows:

[0021] For the calculation of the total vibration level at N different frequencies of a certain evaluation point j in the harmonic response analysis, the sum of the vibration levels at each frequency is taken:

[0022]

[0023] In the formula, is the total vibration level of the evaluation point j, is the vibration level of evaluation point j at the i-th frequency;

[0024] Assuming there are K evaluation points, the acceleration level L all is the average value of the total vibration level of each evaluation point:

[0025]

[0026] Finally, the acceleration level drop is expressed as:

[0027]

[0028] Where, L r is the acceleration level drop, is the acceleration level of the panel on the base, is the acceleration level of the lower panel of the base.

[0029] In the above scheme, the transient impact simulation method is used to simulate the base model to obtain the impact amplification factor, including:

[0030] The transient impact simulation method uses a three-fold impact spectrum to simulate, and converts the impact spectrum into a positive and negative double triangle wave acceleration time history curve for loading, and extracts the output load curve and amplitude of the base model;

[0031] The impact amplification factor is calculated by the ratio of the input impact load amplitude at the base root to the output load amplitude of the base panel:

[0032]

[0033] Where η is the impact amplification factor, a m is the maximum amplitude of the output response, a i is the maximum value of the input load.

[0034] In the above scheme, the response surface methodology uses the central composite design method;

[0035] The central composite design method was used to carry out experimental design and corresponding working condition calculation for two design variables. The accuracy of the fitting model was tested by variance analysis, and a mathematical model of the influence of each design variable on the single performance of the foundation was obtained.

[0036] In the above scheme, the two design variables are encoded into an individual gene string, including:

[0037] Encode each of the two design variables into a string, concatenate the two strings into a long string as the individual gene string; map the decimal value range of each string to the value range of the design variable;

[0038] The selection strategy of the genetic algorithm adopts proportional selection, and the best individuals of the previous generation are forcibly inserted when generating a new population;

[0039] If the secondary optimization objective of the newly generated individual does not meet the secondary optimization objective threshold, the fitness value of the newly generated individual is 0.

[0040] In the above scheme, the method is specifically:

[0041] Based on the parametric modeling method of ABAQUS finite element software, including the method of generating scripts by recording operations and the method of generating scripts by reading JNL files, the model establishment related codes of the parametric modeling script are written; and according to the steady-state excitation simulation method and the transient impact simulation method, the load input, result output, meshing related settings are completed and the related codes are written to form the final parametric modeling script;

[0042] Write a post-processing script to calculate the acceleration level drop and impact amplification factor;

[0043] The main program of the genetic algorithm is written using MATLAB software, and data interaction between MATLAB software and ABAQUS software is realized; after the main program of the genetic algorithm generates the initialized population, the txt file in the specified path is modified according to the individual parameters, and the parametric modeling script reads the txt file to realize the numerical modification, the ABAQUS software is opened and the working directory is set, the parametric modeling script is run and the inp file is output, and after completion, the calculation file and related calculation parameters are submitted to ABAQUS through system call, and the post-processing script is automatically called after the calculation is completed. The post-processing script will extract relevant data, calculate the fitness value and output it in the txt file in the specified path, and the MATLAB software reads the txt file data to realize the return of the fitness value;

[0044] The main genetic algorithm program optimizes two design variables through iteration.

[0045] According to a second aspect of the present invention, there is provided an electronic device comprising: a processor and a memory, the memory storing programs or instructions executable on the processor, the programs or instructions when executed by the processor implementing the steps of any one of the above-mentioned methods for optimizing an integrated vibration-damping and shock-resistant structure applicable to a ship base.

[0046] According to a third aspect of the present invention, there is provided a readable storage medium having a program or instruction stored thereon, which, when executed by a processor, implements the steps of any one of the above-mentioned methods for optimizing a vibration-damping and impact-resistant integrated structure applicable to a ship foundation.

[0047] In general, the above technical solutions conceived by the present invention can achieve the following beneficial effects compared with the prior art:

[0048] The present invention is based on MATLAB and ABAQUS software, takes the integrated structural optimization of vibration reduction and impact resistance of a marine base as a goal, writes steady-state excitation and transient impact scripts based on a parametric modeling method, reasonably selects base design parameters and adopts a response surface method to fit a mathematical model of the influence of the selected design variables on the vibration reduction performance and impact resistance of the base, writes a genetic algorithm main program to realize data interaction between MATLAB software and ABAQUS software, completes relevant settings and performs multi-objective optimization of base structure parameters by means of a constrained response surface fitting model, can realize comprehensive consideration of the vibration reduction performance and impact resistance of the base, and combines genetic algorithm and finite element calculation to ensure the accuracy and reliability of the optimization result.

[0049] In addition, the use of parametric modeling scripts, post-processing scripts and building software interactive functions can improve efficiency and achieve automation, providing a reference for related research on parameter design and optimization of marine foundation structures. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1 This is a flow chart of a vibration reduction and impact resistance integrated structure optimization method applicable to a ship foundation in an embodiment of the present invention;

[0051] Figure 2 A flowchart of the genetic algorithm and software interaction in an embodiment of the present invention;

[0052] Figure 3 It is a parametric schematic diagram of a honeycomb base stretching section in an embodiment of the present invention;

[0053] Figure 4 A three-dimensional negative Poisson's ratio honeycomb base model diagram in an embodiment of the present invention;

[0054] Figure 5 It is a finite element model diagram of steady-state excitation simulation calculation in an embodiment of the present invention;

[0055] Figure 6 Schematic diagram of acceleration level drop calculation evaluation points in an embodiment of the present invention;

[0056] Figure 7 It is a transient impact positive and negative double triangle wave curve diagram in an embodiment of the present invention;

[0057] Figure 8 It is a genetic algorithm fitness optimization curve diagram in an embodiment of the present invention;

[0058] Fig. 9 This is a static load displacement cloud diagram of the optimized model in an embodiment of the present invention. DETAILED DESCRIPTION

[0059] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0060] At present, the structural design of a new type of base is often carried out for a single goal and lacks parameter optimization. To address this problem, the present invention is based on parametric modeling and genetic optimization algorithm, combined with the response surface method to simplify the mathematical model, and combines MATLAB software and ABAQUS software to realize an integrated optimization method for the vibration reduction and impact resistance of the base structure. The method can complete the single-objective optimization and multi-objective optimization of the vibration reduction performance and impact resistance of various marine bases such as the negative Poisson's ratio honeycomb base, and provide a reference for the parameter design of the corresponding base structure.

[0061] Example 1

[0062] The vibration reduction and impact resistance integrated structure optimization method applicable to the ship foundation of this embodiment is as follows: Figure 1 and Figure 2 As shown, the following steps are included:

[0063] (1) Based on the parametric modeling method, steady-state excitation simulation calculation method and transient impact simulation calculation method of ABAQUS finite element software, a parametric modeling script is written for the design model.

[0064] (2) Select reasonable evaluation criteria for relevant performance, including acceleration level drop and impact amplification factor, and write a calculation post-processing script corresponding to the parameterized modeling script.

[0065] (3) Finally, the optimal design variables are selected, and the response surface method is used to carry out experimental design and corresponding operating condition calculation for each design variable. The accuracy of the fitting model is tested by variance analysis to obtain a mathematical fitting model of the influence of each design variable on the single performance of the base.

[0066] (4) In order to achieve multi-objective optimization of the base performance, a MATLAB genetic algorithm master program was written and an interaction method with ABAQUS finite element software was established.

[0067] (5) Set genetic algorithm related parameters such as genetic generation, population size, and structural design related parameters such as structural parameter value range, weight constraints, etc. in the MATLAB main control program.

[0068] (6) Genetic algorithm optimization is carried out through the master control program formed by steps (4) and (5), and ABAQUS software is called to calculate the corresponding individual fitness values, and the base structure design parameters are optimized generation by generation to obtain the final optimization results.

[0069] (7) Based on the final optimization parameters of step (6), multiple parametric modeling scripts are generated to calculate and test the static load-bearing performance, vibration reduction performance and impact resistance of the optimized base. If the corresponding requirements are met, the calculation is terminated, otherwise step (6) is repeated.

[0070] Preferably, in step (1), the preliminary stretching sketch of the base design structure is parameterized, and based on the parametric modeling method of ABAQUS finite element software, including the script generation method of recording operation and the script generation method of reading JNL file, the model establishment related code of the parametric modeling script is written; according to the steady-state excitation simulation method and the transient impact simulation method, the load input, result output, meshing and other related settings are completed and the related code is written to form the final parametric modeling script. Figure 3 As shown, the design parameters of the base include: main side length L1, oblique side length L2, extended support length L3, cell angle α and honeycomb thickness T H .

[0071] Preferably, the steady-state excitation simulation method uses the modal superposition method to perform harmonic response analysis and extracts the acceleration data at each evaluation point of the base as the output result; the transient impact simulation method uses a three-fold impact spectrum simulation, such as Figure 7 As shown, the impact spectrum is converted into an acceleration time history curve of positive and negative double triangle waves for loading, and finally the base output load curve and its amplitude are extracted as the output results.

[0072] Preferably, in step (2), the acceleration level drop is used to evaluate the vibration reduction performance of the base, and the impact amplification coefficient is used to evaluate the impact resistance of the base, and a corresponding post-processing script is written to complete the data processing calculation.

[0073] The calculation method of acceleration level difference is as follows:

[0074] For the calculation of the total vibration level at N different frequencies of a certain evaluation point j in the harmonic response analysis, the sum of the vibration levels at each frequency is taken:

[0075]

[0076] In the formula, is the total vibration level of the evaluation point j, is the vibration level of the evaluation point j at the ith frequency (i.e., the vibration acceleration level, which can be obtained by substituting the acceleration data into the formula and calculating the sum);

[0077] Assuming there are K evaluation points, the acceleration vibration level of the structure is the average value of the vibration levels of each evaluation point:

[0078]

[0079] The acceleration level drop can be expressed as:

[0080]

[0081] The calculation method of the impact amplification factor is as follows:

[0082] The calculation is based on the ratio of the input impact load amplitude at the base root to the output load amplitude of the base panel:

[0083]

[0084] In the formula, a m is the maximum amplitude of the output response, a i is the maximum value of the input load.

[0085] Preferably, in step (3), the base optimization structural parameter target is selected, and the central composite design method (central composite design) is used for experimental design according to the number of parameters. After completing the calculation of all design conditions, it is necessary to perform variance analysis on the fitting results. In the analysis results: R 2 is the correlation coefficient, R 2 The higher the value, the higher the fitting accuracy of the model; the significance of the influence of each factor on the response index is obtained by the F test, and the smaller the P value, the more significant the influence of the independent variable on the response value; the model P value is less than 0.05, which indicates that the final fitted mathematical model is significant and the selected influencing factors are reasonable and effective.

[0086] Preferably, in step (4), the functions of the main program of the genetic algorithm include: initializing the population, calculating the fitness of the population, selection, crossover, mutation, and recombination, wherein the selection strategy adopts a proportional selection method, and the probability of an individual being selected to enter the next generation is determined according to its fitness; to ensure that the calculation results are optimized from generation to generation, the best individual of the previous generation is forcibly inserted when the new population is generated by recombination; and the interaction with the ABAQUS finite element software is realized in the code for calculating the fitness of the population, and the main interactive functions include modifying the parametric modeling script through a txt file, submitting the calculation file to the system, and reading the calculation results through a txt file.

[0087] Preferably, in step (5), genetic algorithm related parameters and structural design related parameters are set according to actual needs, combined with engineering processing restrictions and lightweight and other related design concepts, and finally the constraints of the optimization algorithm can be defined.

[0088] Preferably, in step (6), the individual fitness value is calculated and output in a txt file under a specified path by ABAQUS finite element software. According to the difference in the calculation condition type, the individual fitness value is the evaluation index value of the corresponding condition, including the acceleration level drop and the impact amplification factor. In order to achieve multi-objective optimization of the vibration reduction and impact resistance of the base, the extreme value or fixed range of another optimization target response surface fitting model is set in the main program of the genetic algorithm. When the optimization parameter is substituted into the calculation result and the corresponding requirements are not met, the ABAQUS calculation link is skipped, and the individual fitness value is directly returned to 0, completing the comprehensive consideration of multiple performances.

[0089] Preferably, in step (7), the static load-bearing performance of the base is calculated by static loading using a vertical force of 500 kg, and the ratio of the maximum displacement of the base to the original scale is used as the basis for evaluation.

[0090] Example 2

[0091] This embodiment takes the optimization of vibration reduction and impact resistance performance of a certain plate-frame three-dimensional negative Poisson's ratio honeycomb base as an example to illustrate, and the method includes the following steps:

[0092] (1) According to the plate-frame three-dimensional negative Poisson's ratio honeycomb base structure, its tensile section is parameterized and the corresponding script is written. The tensile entity is rotated 90° and combined to obtain a unit cell structure model. The unit cell model is arranged and combined in the X, Y, and Z directions to obtain a honeycomb core layer structure model, such as Figure 4 As shown, all displacements are represented by the combination of parameters, and the complete modeling process can be completed automatically.

[0093] (2) Figure 5 As shown, according to the steady-state excitation and transient impact simulation calculation method, by reading the JNL file and modifying the relevant setting code, the shell unit thickness, grid size, etc. are also expressed in parameter form, and combined with the modeling code to form the final parameterized modeling script file.

[0094] (3) According to the acceleration level difference calculation formula, write code to extract and calculate the acceleration curve data and acceleration level difference of a point set consisting of 9 evaluation points, such as Figure 6 As shown; according to the impact amplification coefficient calculation formula, write the code to extract and calculate the reference point impact amplification coefficient; supplement the code to output the calculation results in a fixed format to a txt file under the specified path, forming two sets of post-processing script files corresponding to their respective working conditions.

[0095] (4) The relevant optimizable parameters of this example include the main side length L1, the hypotenuse length L2, the extended support length L3, the cell angle α and the honeycomb thickness T H Any combination of any two of them can be used to carry out subsequent optimization steps. In this example, the cell angle and honeycomb thickness are selected as the design variables of the negative Poisson's ratio honeycomb base, and the acceleration level drop and impact amplification factor of the honeycomb base are taken as the optimization targets. The CCD experimental design method in the response surface method is used to select the parameter value range to obtain the required pre-condition calculation table, as shown in Table 1.

[0096] Table 1 CCD test design table

[0097]

[0098] (5) Calculate the corresponding working condition results according to the design table, select a reasonable model for fitting, and use variance analysis to test the model accuracy, as shown in Tables 2 and 3.

[0099] Table 2 Acceleration level drop fitting variance analysis table

[0100]

[0101] Table 3 Analysis of variance table of shock amplification coefficient fitting

[0102]

[0103]

[0104] The response surface model of acceleration level drop and impact amplification factor is finally obtained as follows:

[0105]

[0106] (6) The main program of the genetic algorithm is written using MATLAB software. The cell angle and honeycomb thickness are encoded as individual gene strings. In this example, the length of the individual string is 20, and the length of each string of the two optimization variables is 10. The decimal value range returned by the decoding function is 0 to 1024 (2 10 ), and its value range can be adjusted by zooming and translating; the selection strategy adopts proportional selection, and the best individuals of the previous generation are forcibly inserted when generating a new population.

[0107] (7) Build software interaction function: After the genetic algorithm main program generates the initialized population, modify the txt file in the specified path according to the individual parameters, and the parametric modeling script reads the txt file to realize the numerical modification. Open the ABAQUS software and set the working directory, run the parametric modeling script and output the inp file. After completion, submit the calculation file and related calculation parameters to ABAQUS through system call, and automatically call the post-processing script after the calculation is completed. The script will extract relevant data, calculate the fitness value and output it in the txt file in the specified path. The MATLAB software reads the txt file data to realize the return of the fitness value.

[0108] (8) After selecting the main optimization target, the input of the other optimization target uses the response surface fitting model as the mathematical model constraint condition. In this example, the acceleration level drop is the main optimization target, and the optimization of the impact resistance of the base is written into the constraint condition in the form of limiting the calculation result of the fitting model of the impact amplification factor to no more than 0.8. The final optimization mathematical model and constraint conditions are as follows:

[0109]

[0110] For the main optimization target, the parameterized modeling script and the post-processing script are used to accurately calculate through model simulation; for the other optimization target, it is directly calculated using the fitting model of step (5).

[0111] (9) Set the initial population size to 4, the individual gene character length to 20, the crossover probability to 0.6, the mutation probability to 0.001, the genetic generation to 100 generations, and the optimization algorithm to end only when the set genetic generation is reached. When the impact amplification coefficient fitting value exceeds the threshold of 0.8, set its return fitness to 0, and perform multi-objective optimization calculations on the negative Poisson's ratio honeycomb base. Figure 8 This is the fitness optimization curve.

[0112] (10) The parameters of the final optimized negative Poisson's ratio honeycomb structure are: cell angle 61.351°, honeycomb thickness 0.953 mm, and its vibration reduction performance, impact resistance, and static load-bearing performance are tested. Fig. 9 As shown, the acceleration level difference is 5.820dB, the impact amplification factor is 0.814, and the maximum displacement under 500kg static force is 1.699mm.

[0113] The present invention aims at a marine base structure, performs parameterization processing on its tensile section based on a parametric modeling method, and writes a parametric modeling script in combination with a steady-state excitation and transient impact finite element calculation method; reasonably selects base design parameters, adopts a CCD test design method in a response surface method and combines it with simulation calculation to fit a mathematical model of the influence of various parameters on the vibration reduction performance and impact resistance of the base; realizes data interaction between MATLAB software and ABAQUS software by writing a genetic algorithm main program, and completes multi-objective generation-by-generation optimization of base structure parameters in combination with a constrained response surface fitting model, a proportional selection method and a method of forcibly inserting the optimal individual.

[0114] The present invention also provides an electronic device, comprising: a processor and a memory, the memory storing programs or instructions that can be run on the processor, and the program or instructions, when executed by the processor, implementing the steps of any one of the above-mentioned methods for optimizing the vibration-damping and impact-resistant integrated structure applicable to a ship base.

[0115] The present invention also provides a readable storage medium having a program or instruction stored thereon, which, when executed by a processor, implements the steps of any one of the above-mentioned methods for optimizing a vibration-damping and impact-resistant integrated structure applicable to a ship foundation.

[0116] In summary, the present invention is based on MATLAB and ABAQUS software, takes the integrated structural optimization of marine foundation vibration reduction and impact resistance as the direction, writes steady-state excitation and transient impact scripts based on the parametric modeling method, reasonably selects the foundation design parameters and adopts the response surface method to fit the mathematical model of its influence on the foundation vibration reduction performance and impact resistance, writes the genetic algorithm main program to realize the data interaction between MATLAB software and ABAQUS software, completes the relevant settings and performs multi-objective optimization of the foundation structure parameters by means of constrained response surface fitting model, and finally performs various performance tests on the foundation after parameter optimization.

[0117] Compared with the prior art, the present invention provides a vibration-damping and impact-resistant integrated structural optimization method suitable for ship foundations. Combined with result processing, the vibration-damping and impact-resistant integrated structural optimization of ship foundations can be effectively realized. By fitting a mathematical model using a response surface, the vibration-damping performance and impact-resistant performance of the foundation can be comprehensively considered under a single working condition calculation. The accuracy and reliability of the optimization results are guaranteed by combining genetic algorithms and finite element calculations. The use of parametric modeling scripts, post-processing scripts and the construction of software interactive functions can improve efficiency and realize automation. This provides a reference for related research on parameter design and optimization of ship foundation structures.

[0118] It should be noted that the size of the serial numbers of the steps in the above embodiments does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0119] It should be pointed out that, according to the needs of implementation, the various steps / components described in this application can be split into more steps / components, and two or more steps / components or partial operations of steps / components can be combined into new steps / components to achieve the purpose of the present invention.

[0120] It will be easily understood by those skilled in the art that the above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A vibration reduction and impact resistance integrated structure optimization method suitable for ship foundation, characterized in that: The method includes: The tensile section of the plate-frame three-dimensional negative Poisson's ratio honeycomb base structure is parameterized to obtain the design parameters of the base. Select two design parameters from the design parameters of the base as design variables, and take the remaining design parameters as constants, and establish a base model based on a parametric modeling method; The base model is simulated by using a steady-state excitation simulation method to obtain the acceleration level drop, and the base model is simulated by using a transient impact simulation method to obtain the impact amplification factor; wherein, the acceleration level drop is used to evaluate the vibration reduction performance of the base, and the impact amplification factor is used to evaluate the impact resistance performance of the base; The response surface method is used to fit the mathematical model of the two design variables on the vibration reduction performance and the impact resistance performance, and the response surface model of the acceleration level drop and the impact amplification factor is obtained. Encode the two design variables into an individual gene string; Select vibration reduction performance or impact resistance as the main optimization target, and the other as the secondary optimization target; the main optimization target is obtained by model simulation and used as the individual fitness; the secondary optimization target is obtained by the response surface model, and the threshold of the secondary optimization target is set as a constraint condition; Genetic algorithm is used to optimize two design variables.

2. The vibration reduction and impact resistance integrated structure optimization method applicable to a ship foundation according to claim 1, characterized in that: Build the base model, including: The stretched section is stretched to obtain a stretched entity, the stretched entity is rotated 90 degrees and combined to obtain a unit cell structure model, and the unit cell structure model is arranged and combined in three directions of X, Y, and Z to obtain a base model.

3. The vibration reduction and impact resistance integrated structure optimization method applicable to a ship foundation according to claim 1, characterized in that: The design parameters of the base include: main side length L1, hypotenuse length L2, extended support length L3, cell angle α and honeycomb thickness T H .

4. The vibration reduction and impact resistance integrated structure optimization method applicable to a ship foundation according to claim 1, characterized in that: The base model is simulated using the steady-state excitation simulation method to obtain the acceleration level drop, including: The steady-state excitation simulation method uses the modal superposition method to perform harmonic response analysis, extracts the acceleration data at each evaluation point in the base model, and obtains the vibration level through calculation and processing; The calculation method of acceleration level difference is as follows: For the calculation of the total vibration level at N different frequencies of a certain evaluation point j in the harmonic response analysis, the sum of the vibration levels at each frequency is taken: In the formula, is the total vibration level of the evaluation point j, is the vibration level of evaluation point j at the i-th frequency; Assuming there are K evaluation points, the acceleration level L all is the average value of the total vibration level of each evaluation point: Finally, the acceleration level drop is expressed as: Where, L r is the acceleration level drop, is the acceleration level of the panel on the base, is the acceleration level of the lower panel of the base.

5. The vibration reduction and impact resistance integrated structure optimization method applicable to a ship foundation according to claim 1, characterized in that: The transient impact simulation method is used to simulate the base model to obtain the impact amplification factor, including: The transient impact simulation method uses a three-fold impact spectrum to simulate, and converts the impact spectrum into a positive and negative double triangle wave acceleration time history curve for loading, and extracts the output load curve and amplitude of the base model; The impact amplification factor is calculated by the ratio of the input impact load amplitude at the base root to the output load amplitude of the base panel: Where η is the impact amplification factor, a m is the maximum amplitude of the output response, a i is the maximum value of the input load.

6. The vibration reduction and impact resistance integrated structure optimization method applicable to a ship foundation according to claim 1, characterized in that: The response surface methodology uses the central composite design method; The central composite design method was used to carry out experimental design and corresponding working condition calculation for two design variables. The accuracy of the fitting model was tested by variance analysis, and a mathematical model of the influence of each design variable on the single performance of the foundation was obtained.

7. The vibration reduction and impact resistance integrated structure optimization method applicable to a ship foundation according to claim 1, characterized in that: Encode the two design variables into an individual gene string consisting of: Encode each of the two design variables into a string, concatenate the two strings into a long string as the individual gene string; map the decimal value range of each string to the value range of the design variable; The selection strategy of the genetic algorithm adopts proportional selection, and the best individuals of the previous generation are forcibly inserted when generating a new population; If the secondary optimization objective of the newly generated individual does not meet the secondary optimization objective threshold, the fitness value of the newly generated individual is 0.

8. The vibration reduction and impact resistance integrated structure optimization method applicable to a ship foundation according to claim 1, characterized in that: The method is as follows: Based on the parametric modeling method of ABAQUS finite element software, including the method of generating scripts by recording operations and the method of generating scripts by reading JNL files, write the model establishment related codes of the parametric modeling script; According to the steady-state excitation simulation method and transient impact simulation method, complete the load input, result output, mesh division related settings and write related codes to form the final parameterized modeling script; Write a post-processing script to calculate the acceleration level drop and impact amplification factor; The main program of the genetic algorithm is written using MATLAB software, and data interaction between MATLAB software and ABAQUS software is realized; after the main program of the genetic algorithm generates the initialized population, the txt file in the specified path is modified according to the individual parameters, and the parametric modeling script reads the txt file to realize the numerical modification, the ABAQUS software is opened and the working directory is set, the parametric modeling script is run and the inp file is output, and after completion, the calculation file and related calculation parameters are submitted to ABAQUS through system call, and the post-processing script is automatically called after the calculation is completed. The post-processing script will extract relevant data, calculate the fitness value and output it in the txt file in the specified path, and the MATLAB software reads the txt file data to realize the return of the fitness value; The main genetic algorithm program optimizes two design variables through iteration.

9. An electronic device, characterized in that: include: A processor and a memory, the memory storing programs or instructions that can be run on the processor, and the programs or instructions, when executed by the processor, implement the steps of the vibration-damping and impact-resistant integrated structure optimization method applicable to a ship foundation as described in any one of claims 1 to 8.

10. A readable storage medium, characterized in that: Programs or instructions are stored thereon, and when the programs or instructions are executed by the processor, the steps of the vibration-damping and impact-resistant integrated structure optimization method applicable to a ship foundation as described in any one of claims 1 to 8 are implemented.

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