L-shaped swash plate and design optimization method thereof

Abstract

The invention discloses an L-shaped swash plate and a design optimization method thereof.The L-shaped swash plate comprises a transverse plate, an arc plate, a longitudinal plate, a vent hole, a liquid through hole and a manhole, the first edge section of the transverse plate is matched with the edge of the cross section of a tank body, one side of the arc plate is connected with the second edge section, the longitudinal plate is connected to the other side of the arc plate, and the liquid through hole is formed in the longitudinal plate; the vent hole and the liquid through hole are formed in the upper end and the bottom end of the joint of the transverse plate and the arc plate respectively, and the manhole is formed in the longitudinal plate; according to the design optimization method, a response surface approximation model of design variables of the L-shaped swash plate and liquid tank truck liquid shake response is constructed through a finite element method and a response curved surface method, a mathematical model of the multi-objective optimization problem of the L-shaped swash plate is constructed, and the mathematical model is solved through an improved non-dominated sorting genetic algorithm (NSGA-III). And analyzing and determining an optimal design parameter combination of the L-shaped swash plate. The swash plate can effectively restrain transverse and longitudinal shaking impact of liquid in the tank on the basis of meeting the light weight requirement of the swash plate.

Description

Technical Field

[0001] The invention relates to the technical field of wave-breaking plates for liquid tank trucks, and in particular to an L-shaped wave-breaking plate and a design optimization method thereof. Background Art

[0002] During the process of turning, emergency braking and obstacle avoidance, the liquid in the tank will sway violently due to inertia, thus affecting driving safety. In order to effectively suppress the swaying of the liquid in the tank and reduce the impact of the liquid on the head, partition plate and cylinder, a certain number of wave-breaking plates are generally installed in the tank of the tank truck. At present, the most widely used wave-breaking plates are flat wave-breaking plates and butterfly wave-breaking plates. Such wave-breaking plates can effectively reduce the swaying degree of the liquid in the tank under emergency braking conditions and reduce the longitudinal impact force of the liquid. However, when the tank is not fully loaded and is in a turning condition, especially for large tank trucks, studies have shown that when the filling ratio is greater than 0.5, its roll stability is poor, and the lateral sway reduction ability of the flat wave-breaking plates and butterfly wave-breaking plates is weak, which cannot effectively suppress the lateral swaying impact of the liquid in the tank, resulting in the tank truck being prone to rollover accidents. Although there are also related technologies that simultaneously set lateral and longitudinal wave-breaking plates in the tank to improve the comprehensive anti-sway ability of the wave-breaking plates, it greatly increases the mass of the tank. Therefore, it is urgent to develop an L-shaped wave-breaking plate to effectively suppress the lateral and longitudinal shaking impact force of the liquid in the tank and meet the design requirements of lightweight whole vehicle.

[0003] On the other hand, with the rapid development of design methods, a variety of modern design methods such as finite element method, multi-objective optimization design method and computer-aided design have been widely used. However, the existing wave-breaking board design methods are still mainly based on the design experience of engineers, lacking a rigorous analysis and research process, and there is no set of standardized optimization design methods. In addition, in the process of wave-breaking board optimization design, there may be mutual constraints between different design evaluation indicators. For example, the lightweight design of wave-breaking boards often comes at the expense of the strength of wave-breaking boards. Therefore, for the multi-objective optimization design problem of wave-breaking boards, it is also urgent to design a comprehensive optimization design method. By establishing a reasonable multi-objective optimization mathematical model and solving the algorithm according to the characteristics of the model, the optimal combination of wave-breaking board design parameters can be obtained through analysis. Summary of the invention

[0004] The purpose of the present invention is to provide an L-shaped wave-breaking plate for a liquid tank truck and a design optimization method thereof, which can effectively suppress the lateral and longitudinal shaking impact of the liquid in the tank on the basis of meeting the lightweight requirements of the entire vehicle, and solve the technical problems that the existing wave-breaking plates are insufficient in suppressing the lateral shaking impact of the liquid in the tank, resulting in easy rollover, and the existing wave-breaking plate design methods lack scientificity.

[0005] In order to achieve the above technical objectives, the present invention adopts the following technical solutions: In one aspect, the present invention provides an L-shaped wave-breaking board, comprising: A transverse plate, the transverse plate having a first edge section and a second edge section, the first edge section matching a portion of an edge of a cross section of the tank body; A circular arc plate, one side of which is connected to the second edge section of the transverse plate; A longitudinal plate connected to the other side of the arc plate; The ventilation holes, liquid holes and manholes are respectively arranged at the upper end and the bottom end of the connection between the horizontal plate and the arc plate, and the manhole is arranged on the longitudinal plate.

[0006] In some embodiments, the first edge segment of the transverse plate is formed by five arc segments connected end to end in sequence.

[0007] In some embodiments, the air vent and the liquid hole are both circular holes, the manhole is an elliptical hole, and the center of the manhole is offset in the horizontal and vertical directions relative to the symmetry center of the longitudinal plate.

[0008] In some embodiments, the short axis length of the manhole is greater than the diameter of the liquid hole, and the diameter of the liquid hole is greater than the diameter of the ventilation hole.

[0009] In some embodiments, it also includes a wave-breaking plate reinforcement ring, which is welded to the edges of the transverse plate, the arc plate and the longitudinal plate.

[0010] In some embodiments, a liquid hole reinforcement ring is also included, and the liquid hole reinforcement ring is welded to the circumferential edge of the liquid hole.

[0011] In some embodiments, a manhole reinforcement ring is also included, and the manhole reinforcement ring is welded to the circumferential edge of the manhole.

[0012] On the other hand, the present invention provides an L-shaped wave-breaking plate design optimization method, which is used to design the L-shaped wave-breaking plate as described in any one of claims 1 to 7 above, and constructs a response surface approximation model of the design variables of the L-shaped wave-breaking plate and the liquid sloshing response of the tank truck through the finite element method and the response surface method, and constructs a mathematical model of the multi-objective optimization problem of the L-shaped wave-breaking plate, and uses an improved non-dominated sorting genetic algorithm (NSGA-III) with an elite strategy to solve the mathematical model to obtain the Pareto optimal solution set, and finally uses the finite element method to perform a fluid-solid coupling experiment to determine the optimal design parameter combination of the L-shaped wave-breaking plate.

[0013] In some embodiments, the design optimization method comprises the following steps: Step 1: parametrically model the L-shaped wave-breaking plate, complete the parametric modeling of the L-shaped wave-breaking plate and construct the geometric model of the tank truck body in SolidWorks; Step 2: Use the control variable method to conduct a single factor experiment on the design parameters of the L-shaped wave-breaking plate, obtain the liquid sloshing response of each design scheme through numerical simulation experiments, analyze the influence of the design parameters on the liquid sloshing response, and preliminarily narrow the value range of each design parameter; Step 3, through the Plackett-Burman experiment, the significant factors affecting the longitudinal impact force of the liquid during the braking process of the tank truck, the force on the first wave-breaking board, and the roll moment during the turning process are screened out; Step 4, using the steepest climbing test to determine the high level, medium level and low level of the design parameters of the L-shaped wave-breaking board; Step 5, using Box-Behnken design to determine the design scheme, and obtaining the liquid sloshing response of each design scheme through numerical simulation experiments; taking the horizontal axis a and the vertical axis b of the manhole on the longitudinal plate of the L-shaped wave-breaking plate, the horizontal offset distance c of the manhole, and the vertical offset distance d of the manhole as independent variables, and taking the peak value F1 of the longitudinal impact force of the liquid during the braking process of the tank truck, the peak force F2 of the first wave-breaking plate, and the peak value M of the rolling moment of the tank truck during the turning process as dependent variables, using the least squares method to fit the quadratic polynomial to determine the regression equations of the three liquid sloshing responses of the L-shaped wave-breaking plate; the basic form of the second-order polynomial regression equations of the three liquid sloshing responses of the L-shaped wave-breaking plate is:

[0014] Where: is the number of design parameters; is the intercept term; Indicates design parameters The linear effect of Indicates design parameters and The linear interaction effect of Design parameters The quadratic linear effect of represents the random error term; Step 6, evaluate the regression equation; Calculate the root mean square error (RMSE), coefficient of variation (CV), and coefficient of determination (R-Square) of the regression equations of the three liquid sloshing responses of the L-shaped wave-breaking plate respectively. If the root mean square error of the regression equation is less than 0.5, the coefficient of variation is less than 10%, and the coefficient of determination is greater than 95%, then execute step 7. Otherwise, check the distribution diagram of the predicted value and the actual value, re-conduct the numerical simulation experiment for the points with large deviations, and return to step 5 until the evaluation indicators of the regression equation meet the above requirements. Step 7, taking the transverse axis a and the longitudinal axis b of the manhole on the longitudinal plate of the L-shaped wave-breaking plate, the horizontal offset distance c of the manhole and the vertical offset distance d of the manhole as design variables, taking the peak longitudinal impact force F1 of the liquid during the braking process of the tank truck, the peak force F2 of the first wave-breaking plate, the peak roll moment M of the tank truck during the turning process and the mass m of the L-shaped wave-breaking plate as optimization targets, taking the value range of the design parameters of the L-shaped wave-breaking plate determined by the steepest climbing experiment as constraint conditions, the mathematical model of the multi-objective optimization problem of the L-shaped wave-breaking plate is:

[0015] Step 8, according to the established mathematical model of the multi-objective optimization problem of the L-shaped wave-breaking plate, the improved non-dominated sorting genetic algorithm NSGA-Ⅲ with elite strategy is used to solve the mathematical model and obtain the Pareto optimal solution set; Step 9: Conduct fluid-solid coupling experiments on the tank truck under braking and turning conditions based on the Pareto optimal solution set, select the design parameter combination in which the overall force of the tank truck body meets the design requirements and all evaluation indicators of the wave-breaking plate reach a relatively low level as the Pareto optimal solution, output the Pareto optimal solution, and use it as the optimal design parameter combination for the L-shaped wave-breaking plate.

[0016] In some embodiments, the regression equations of the three liquid sloshing responses of the L-shaped wave-breaking plate in step 5 are: 1) The regression equation of the peak value F1 of the longitudinal impact force of the liquid when the tank truck is braked is:

[0017] 2) The regression equation of the peak force F2 of the first wave-breaking plate when the tank truck is braked is:

[0018] 3) The regression equation of the peak value M of the rolling moment when the tank truck turns is: .

[0019] Compared with the prior art, the beneficial effects of the present invention include the following two aspects: 1. The present invention provides an L-shaped wave-breaking plate arranged inside the tank body of a liquid tank truck. When the liquid tank truck accelerates, decelerates, brakes urgently or turns, it can effectively slow down the longitudinal and lateral shaking of the liquid in the tank body, thereby improving the driving stability of the vehicle under various working conditions; 2. The present invention provides an L-shaped wave-breaking board design optimization method. The second-order polynomial regression equation of the wave-breaking board design parameters and liquid sloshing response is established through single-factor experiments, Plackett-Burman experiments, steepest climbing experiments and Box-Behnken experimental designs. The regression equation is evaluated by root mean square error (RMSE), coefficient of variation (CV) and coefficient of determination (R-Square), ensuring the accuracy of the equation. The improved NSGA-Ⅲ algorithm is proposed to solve the mathematical model of the multi-objective optimization problem of the L-shaped wave-breaking board. Latin hypercube sampling is combined with reference points to initialize the population, ensuring the diversity and uniform distribution of the initial population individuals; the crossover and variation distribution index is introduced, and the corresponding distribution index is adaptively generated according to the difference between the population individuals and the ideal point to perform adaptive crossover and variation on the population individuals, thereby improving the algorithm's solution efficiency and avoiding the algorithm from falling into the local optimal solution set too early. Finally, based on the Pareto optimal solution set and conducting fluid-solid coupling experiments, the optimal design parameter combination of the wave-breaking board is determined. This optimization design method improves the design process of the wave-breaking board and improves the design efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 is a schematic structural diagram of the L-shaped wave-breaking plate of the present invention; Figure 2 is a schematic diagram of the L-shaped wave-breaking plate of the present invention being arranged inside the tank of a liquid tank truck; Figure 3 yes Figure 2 The main view of Figure 4 yes Figure 2 A top view of Figure 5 It is the dimension parameter diagram of the L-shaped wave-breaking board of the present invention (horizontal board); Figure 6 is a dimension parameter diagram of the L-shaped wave-breaking board of the present invention (longitudinal board); Figure 7 yes Figure 6 AA section view in; Figure 8 is a flow chart of the design optimization method of the L-shaped wave-breaking plate of the present invention; Fig. 9 It is a flow chart of the multi-objective optimization algorithm based on NSGA-Ⅲ described in the present invention.

[0021] The following are the descriptions of the reference numerals: 100, L-shaped wave-breaking plate, 110, horizontal plate, 120, arc plate, 130, longitudinal plate, 140, vent hole, 150, liquid hole, 160, manhole, 170, wave-breaking plate reinforcement ring, 180, liquid hole reinforcement ring, 190, manhole reinforcement ring; 200, tank body; DETAILED DESCRIPTION In order to make the purpose, technical solution 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.

[0022] See also Figures 1 to 7 As shown, on the one hand, the present invention provides an L-shaped wave-breaking plate 100, which is arranged inside the tank body 200 of the liquid tank truck, and includes a transverse plate 110, an arc plate 120, a longitudinal plate 130, an air vent 140, a liquid through hole 150 and a manhole 160, wherein the transverse plate 110 matches the cross-sectional shape of the tank body 200, specifically, the transverse plate includes a first edge segment and a second edge segment, the first edge segment matches a partial edge of the cross section of the tank body 200, one side of the arc plate 120 is connected to the second edge segment of the transverse plate 110, and the longitudinal plate 130 is connected to the other side of the arc plate 120; the air vent 140 and the liquid through hole 150 are respectively opened at the upper end and the bottom end of the connection between the transverse plate 110 and the arc plate 120, and the manhole 160 is opened on the longitudinal plate 130.

[0023] When in use, the L-shaped wave-breaking plate involved in the technical solution of the present invention has a transverse plate 110 arranged along the transverse direction of the tank body 200, and a longitudinal plate 130 arranged along the longitudinal direction of the tank body 200. The transverse plate 110 matches the cross-sectional shape of the tank body 200, and the longitudinal length of the longitudinal plate 130 is the spacing between two adjacent L-shaped wave-breaking plates 100. Then, multiple L-shaped wave-breaking plates 100 are arranged inside the tank body 200 of the liquid tank truck. When the liquid tank truck accelerates, decelerates, brakes urgently or turns, the longitudinal and lateral shaking of the liquid in the tank body 200 can be effectively slowed down, thereby improving the driving stability of the vehicle under various working conditions. In one embodiment, the first edge section of the transverse plate 110 is composed of five arc segments, which are arc segments formed by specific centers and radii, and the air holes 140 and the liquid holes 150 are both circular holes.

[0024] In this embodiment, the radii of the five arcs are R1=2794mm, R2 and R4 are 594mm, R3=1794mm, and R5=2494mm respectively; the center of the air vent 140 is point O1 and the diameter D1 is 120mm, the center of the liquid hole 150 is point O2 and the diameter D2 is 280mm, and the center O1 of the air vent 140, the center O2 of the liquid hole 150 and the longitudinal symmetry center O of the tank body 200 are on the same straight line.

[0025] In one embodiment, if Figure 6As shown, the manhole 160 is an elliptical hole, and the center E1 of the manhole 160 is offset by a certain distance in the horizontal and vertical directions relative to the symmetry center E of the longitudinal plate 130 .

[0026] In this embodiment, the short axis of the manhole 160 is the horizontal axis a, the long axis is the longitudinal axis b, the center E1 of the manhole 160 is offset by a distance c in the horizontal direction relative to the symmetry center E of the longitudinal plate 130, and the center E1 of the manhole 160 is offset by a distance d in the vertical direction relative to the symmetry center E of the longitudinal plate 130.

[0027] In one embodiment, the short axis length of the manhole 160 is greater than the diameter of the liquid hole 150 , and the diameter of the liquid hole 150 is greater than the diameter of the vent hole 140 .

[0028] In one of the embodiments, a wave-breaking plate reinforcement ring 170 is further included, and the wave-breaking plate reinforcement ring 170 is welded to the edges of the transverse plate 110 , the arc plate 120 and the longitudinal plate 130 .

[0029] In one of the embodiments, a liquid through hole reinforcement ring 180 is further included, and the liquid through hole reinforcement ring 180 is welded to the circumferential edge of the liquid through hole 150 .

[0030] In one of the embodiments, a manhole reinforcement ring 190 is further included, and the manhole reinforcement ring 190 is welded to the circumferential edge of the manhole 160 .

[0031] Take a certain type of gasoline tanker of Company A as the research object, such as Figure 2-4 As shown, the L-shaped wave-breaking plates 100 are evenly arranged in the tank body 200, and the size parameters of the L-shaped wave-breaking plates 100 are as follows: Figure 5-7 As shown, the cross-section of the tank body 200 of the tank truck is a circular rectangle, consisting of 8 arc segments, the transverse plate 110 is composed of five arc segments matching it, the thickness of the L-shaped wave-breaking plate 100 is 6 mm, the width W1 of the wave-breaking plate reinforcement ring 170, the manhole reinforcement ring 190 and the liquid hole reinforcement ring 180 are all 140 mm and the thickness is 6 mm, the width W2 of the transverse plate 110 is 1234 mm, and the length L of the longitudinal plate 120 is 1224 mm.

[0032] On the other hand, Figure 8As shown, the present invention provides an L-shaped wave-breaking plate design optimization method, which is used to design the L-shaped wave-breaking plate 100 provided by the first aspect of the present invention, and constructs a response surface approximation model of the design variables of the L-shaped wave-breaking plate and the liquid sloshing response of the tank truck through the finite element method and the response surface method, and constructs a mathematical model of the multi-objective optimization problem of the L-shaped wave-breaking plate, and uses an improved non-dominated sorting genetic algorithm (NSGA-III) with an elite strategy to solve the mathematical model to obtain the Pareto optimal solution set, and finally uses the finite element method to perform a fluid-solid coupling experiment to determine the optimal design parameter combination of the L-shaped wave-breaking plate.

[0033] Specifically, the design optimization method of the L-shaped wave-breaking plate 100 includes the following steps: Step 1: parametrically model the L-shaped wave-breaking plate, complete the parametric modeling of the L-shaped wave-breaking plate in SolidWorks and build the geometric model of the tank truck superstructure.

[0034] Step 2: Use the control variable method to conduct a single factor experiment on the design parameters of the L-shaped wave-breaking plate, obtain the liquid sloshing response of each design scheme through numerical simulation experiments, analyze the influence of the design parameters on the liquid sloshing response, and preliminarily narrow the value range of each design parameter; The specific process of the numerical simulation experiment is as follows: first, complete the mechanical modeling of the wave-breaking plate and the tank body; then import the model into the mesh processing module of Fluent to complete the mesh division of the tank truck; finally, complete the liquid sloshing experiment of the tank truck during braking and turning in Fluent, and output the peak longitudinal impact force F1 of the liquid during braking, the peak force F2 of the first wave-breaking plate, and the peak roll moment M of the tank truck during turning.

[0035] Step 3, through the Plackett-Burman experiment, the significant factors affecting the longitudinal impact force of the liquid during the braking process of the tank truck, the force on the first wave-breaking board, and the roll moment during the turning process are screened out; According to the Plackett-Burman experiment, the significant factors affecting the longitudinal impact force during the braking process of the tank truck are: the horizontal axis a and the vertical axis b of the elliptical manhole on the longitudinal plate of the L-shaped wave-breaking plate, the horizontal offset distance c of the manhole, and the vertical offset distance d of the manhole; the significant factors affecting the force on the first wave-breaking plate during the braking process of the tank truck are: the horizontal axis a and the vertical axis b of the elliptical manhole on the longitudinal plate of the L-shaped wave-breaking plate, and the vertical offset distance d of the manhole; the significant factors affecting the roll moment during the turning process of the tank truck are: the horizontal axis a and the vertical axis b of the elliptical manhole on the longitudinal plate of the L-shaped wave-breaking plate, and the vertical offset distance d of the manhole.

[0036] Step 4: The steepest climbing test is used to determine the high, medium and low levels of the design parameters of the L-shaped wave-breaking board. According to the standard GB18564.1-2019 and the steepest climbing test, the optimal value ranges of the optimization design variables of the L-shaped wave-breaking board are obtained as follows: a∈[500,800], b∈[400,800], c∈[0,300], d∈[0,390], all in mm.

[0037] Step 5, using Box-Behnken design to determine the design scheme, and obtaining the liquid sloshing response of each design scheme through numerical simulation experiments; taking the horizontal axis a and the vertical axis b of the manhole on the longitudinal plate of the L-shaped wave-breaking plate, the horizontal offset distance c of the manhole, and the vertical offset distance d of the manhole as independent variables, and taking the peak value F1 of the longitudinal impact force of the liquid during the braking process of the tank truck, the peak force F2 of the first wave-breaking plate, and the peak value M of the rolling moment of the tank truck during the turning process as dependent variables, using the least squares method to fit the quadratic polynomial to determine the regression equations of the three liquid sloshing responses of the L-shaped wave-breaking plate; the basic form of the second-order polynomial regression equations of the three liquid sloshing responses of the L-shaped wave-breaking plate is:

[0038] Where: is the number of design parameters; is the intercept term; Indicates design parameters The linear effect of Indicates design parameters and The linear interaction effect of Design parameters The quadratic linear effect of represents the random error term.

[0039] Taking a certain model of gasoline tanker of Company A as an example, according to the standards GB 7258-2017 and GB 28373-2012, the peak acceleration of the tanker during normal driving is 6m / s 2 , 4.9m / s 2 The regression equations of the three liquid sloshing responses of the L-shaped wave-breaking plate and the mass equation of the L-shaped wave-breaking plate are as follows: (1) The regression equation for the peak value F1 of the longitudinal impact force of the liquid when the tank truck is braked is:

[0040] (2) The regression equation for the peak force F2 of the first wave-breaking plate when the tank truck is braked is:

[0041] (3) The regression equation of the peak value of the rolling moment M when the tank truck turns is:

[0042] (4) The mass equation of the L-shaped wave-breaking plate is as follows:

[0043] Step 6, evaluate the regression equation; Calculate the root mean square error (RMSE), coefficient of variation (CV), and coefficient of determination (R-Square) of the regression equations of the three liquid sloshing responses of the L-shaped wave-breaking plate respectively. If the root mean square error of the regression equation is less than 0.5, the coefficient of variation is less than 10%, and the coefficient of determination is greater than 95%, then execute step 7. Otherwise, check the distribution diagram of the predicted value and the actual value, re-conduct the numerical simulation experiment for the points with large deviations, and return to step 5 until the evaluation indicators of the regression equation meet the above requirements.

[0044]

[0045]

[0046] In the formula, is the predicted value of the regression model for the i-th sample point; is the actual value of the i-th sample point; is the mean of the sample data.

[0047] Step 7, taking the transverse axis a and the longitudinal axis b of the manhole on the longitudinal plate of the L-shaped wave-breaking plate, the horizontal offset distance c of the manhole and the vertical offset distance d of the manhole as design variables, taking the peak longitudinal impact force F1 of the liquid during the braking process of the tank truck, the peak force F2 of the first wave-breaking plate, the peak roll moment M of the tank truck during the turning process and the mass m of the L-shaped wave-breaking plate as optimization targets, taking the value range of the design parameters of the L-shaped wave-breaking plate determined by the steepest climbing experiment as constraint conditions, the mathematical model of the multi-objective optimization problem of the L-shaped wave-breaking plate is:

[0048] Step 8, according to the established mathematical model of the multi-objective optimization problem of the L-shaped wave-breaking plate, the improved non-dominated sorting genetic algorithm NSGA-Ⅲ with elite strategy is used to solve the mathematical model and obtain the Pareto optimal solution set; Step 9: Conduct fluid-solid coupling experiments on the tank truck under braking and turning conditions based on the Pareto optimal solution set, select the design parameter combination in which the overall force of the tank truck body meets the design requirements and all evaluation indicators of the wave-breaking plate reach a relatively low level as the Pareto optimal solution, output the Pareto optimal solution, and use it as the optimal design parameter combination for the L-shaped wave-breaking plate.

[0049] Specifically, the present invention also proposes an improved NSGA-III multi-objective optimization algorithm.

[0050] In order to improve the efficiency of the NSGA-Ⅲ algorithm and avoid falling into local optimality, the present invention proposes a population initialization based on reference points and Latin hypercube sampling and an adaptive crossover and mutation strategy. Individuals associated with each reference point are generated through Latin hypercube sampling, which ensures the randomness and diversity of the initial population while improving the uniformity of the spatial distribution of the initial population individuals. By using simulated binary crossover operators and polynomial mutations, the corresponding distribution index is introduced, and different distribution indexes are adaptively generated according to the distribution of population individuals, and crossover and mutation are performed. The closer the individual is to the ideal point, the closer the offspring generated by its crossover and mutation are to the parent generation. When the population individuals are too dense or the population individuals are farther away from the ideal point, the search range of the population is expanded by generating a smaller distribution index.

[0051] The improved NSGA-Ⅲ algorithm flow chart is as follows: Fig. 9 As shown in the figure, its content is mainly divided into five parts: the first part (step 1-step 2) is to initialize the population based on the reference point and Latin hypercube sampling; the second part (step 3-step 4) is the adaptive normalization of the population individuals, non-dominated sorting and calculation of the number of microhabitats of the reference point; the third part (step 5) is the tournament selection of the population individuals and adaptive crossover and mutation; the fourth part (step 6-step 7) is to adopt the elite strategy to select excellent individuals to enter the next generation; the fifth part (step 8) is to output the Pareto optimal solution set according to the Pareto frontier. The specific steps of the algorithm are as follows: Step 1: Calculate the hyperplane reference point between the design variables and the objective function The hyperplane reference point is calculated as follows: (1) Construct a (M-1)×1 two-dimensional array X.

[0052]

[0053] Where M is the number of research objects; H is the number of segments for each research object.

[0054] (2) Generated by array X The two-dimensional array Y, each element in Y (j=1,2,…,M-1), and must satisfy .

[0055] (3) Update the elements in array Y.

[0056]

[0057] In the formula, .

[0058] (4) Obtain reference points on each research object to form hyperplane reference points.

[0059]

[0060] Step 2: Population initialization (1) Generate the initial optimal solution of the multi-objective optimization problem: Generate a set of experimental populations based on the orthogonal Latin method and calculate the factors in the population m Level The experimental results and K i m ,according to K i m Determining factors m The optimal level of each factor is determined, and the optimal level of each factor constitutes the initial optimal individual and is put into the initial population.

[0061] (2) Population initialization based on reference points and Latin hypercube sampling The individuals generated by Latin hypercube sampling are associated with the hyperplane reference points of the design variables, and only one individual with the closest distance to each reference point is added to the initial population. The above operation is repeated until all reference points have corresponding individuals, completing the population initialization operation.

[0062] Step 3: Calculate the individual objective function values ​​of the initial population, adaptively normalize the individuals, and perform non-dominated sorting on the individuals.

[0063] The process of population individual adaptive normalization is as follows: (1) Calculate the minimum value of each objective function in the population and use it as the ideal point .

[0064]

[0065] (2) The objective function value of individuals in the mobile population makes the ideal point becomes a zero vector, and the objective function value after the move is expressed as .

[0066]

[0067] (3) Calculate the extreme points on each target axis

[0068] In the formula, the weight vector is the axis direction.

[0069] (4) Normalization of the objective functions of individuals in the population.

[0070]

[0071] In the formula, a is the hyperplane intercept.

[0072] Step 4: Update the number of niches at the reference point, calculate the distance between the population individuals and the reference point of the objective function hyperplane, and associate the individuals with the nearest reference point.

[0073] Step 5: Randomly select two individuals through the tournament selection method, compare their objective function values, the number of microhabitats associated with the reference point, and the distance from the reference point, and select the better individual for adaptive crossover and mutation to generate a new generation of subgroups.

[0074] The calculation method of the adaptive crossover and mutation of parent individuals to generate offspring individuals is as follows: Simulate a binary crossover:

[0075]

[0076]

[0077] In the formula, and is the parent individual; and For the offspring individuals; is a random number, ; is the cross-distribution index; and is a constant term; is the mean point of the population objective function value With ideal point distance; The individual whose objective function value is farther from the ideal point than the other two individuals in the crossover Distance from the ideal point.

[0078] Polynomial mutation:

[0079]

[0080]

[0081]

[0082] In the formula, and They are the parent generation and the mutated offspring individuals respectively; and are the upper and lower limits of the value range of X, is the variation distribution index. and is a constant term; is the objective function value of the mutant individual.

[0083] Step 6: Merge the parent population with the offspring population generated by crossover and mutation into a new population, and perform steps 3 and 4 on the individuals in the population. Select excellent individuals with high non-dominated levels to enter the parent population. If the number of individuals in the parent population exceeds the set value of individuals in the population, screen the last group of individuals in the parent population, and select the individual closest to the reference point corresponding to the reference point with the least number of microhabitats to join the parent population.

[0084] Step 7: Repeat steps 5 and 6 until the number of iterations reaches the maximum value.

[0085] Step 8: Based on the Pareto frontier, the output is the Pareto optimal solution set.

[0086] In summary, in the embodiment of the present invention, taking a certain type of gasoline transport tank truck of enterprise A as an example, the optimal design parameter combination of its L-shaped wave-breaking plate is that the lengths of the horizontal axis a and the vertical axis b of the manhole 160 are 600mm and 700mm respectively, the horizontal offset distance c of the manhole 160 is 300mm, and the vertical offset distance d of the manhole 160 is 160mm; the L-shaped wave-breaking plate after the optimized design is installed, when the filling ratio of the tank truck is 0.6, the peak values ​​of braking and turning acceleration are 6m / s respectively 2 , 4.9m / s 2 The peak longitudinal impact force of the liquid under braking conditions and the peak roll moment during cornering decreased by 40.08% and 15.56% respectively compared to the case without a wave-breaking plate. The roll moment decrease rate increased by 15.14% compared to the original corrugated wave-breaking plate. The weight of the optimized L-shaped wave-breaking plate is 81.39kg. The total weight of the wave-breaking plate of the tank truck equipped with the L-shaped wave-breaking plate is reduced by 36.93% compared to the case when both the transverse and longitudinal wave-breaking plates are installed. Therefore, the optimized L-shaped wave-breaking plate effectively reduces the transverse and longitudinal shaking of the liquid in the tank truck under emergency conditions, improves the driving stability of the vehicle under various working conditions, and makes the vehicle lighter. In addition, the optimization design method of the L-shaped wave-breaking plate provided by the present invention establishes a second-order polynomial regression equation of the wave-breaking plate design parameters and the liquid sloshing response through single-factor experiments, Plackett-Burman experiments, steepest climbing experiments and Box-Behnken experimental designs, and evaluates the regression equation through root mean square error (RMSE), coefficient of variation (CV) and coefficient of determination (R-Square), thereby ensuring the accuracy of the equation. The improved NSGA-Ⅲ algorithm is proposed to solve the mathematical model of the multi-objective optimization problem of the L-shaped wave-breaking plate, and Latin hypercube sampling is combined with reference points to initialize the population, thereby ensuring the diversity and uniform distribution of the initial population individuals; the crossover and variation distribution index is introduced, and the corresponding distribution index is adaptively generated according to the difference between the population individuals and the ideal point to adaptively cross and mutate the population individuals, thereby improving the algorithm's solution efficiency and avoiding the algorithm from falling into the local optimal solution set too early. Finally, based on the Pareto optimal solution set and conducting fluid-solid coupling experiments, the optimal design parameter combination of the wave-breaking plate is determined. The optimization design method improves the design process of the wave-breaking plate and improves the design efficiency.

[0087] The specific implementation of the present invention described above does not constitute a limitation on the protection scope of the present invention. Any other corresponding changes and modifications made based on the technical concept of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. An L-shaped wave-breaking plate, arranged inside the tank of a liquid tank truck, characterized in that: include: A transverse plate, the transverse plate having a first edge section and a second edge section, the first edge section matching a portion of an edge of a cross section of the tank body; A circular arc plate, one side of which is connected to the second edge section of the transverse plate; A longitudinal plate connected to the other side of the arc plate; The ventilation holes, liquid holes and manholes are respectively arranged at the upper end and the bottom end of the connection between the horizontal plate and the arc plate, and the manhole is arranged on the longitudinal plate.

2. The L-shaped wave-breaking plate according to claim 1, characterized in that: The first edge section of the transverse plate is formed by connecting five arcs end to end in sequence.

3. The L-shaped wave-breaking plate according to claim 1, characterized in that: The air vent and the liquid hole are both circular holes, the manhole is an elliptical hole, and the center of the manhole is offset in the horizontal and vertical directions relative to the symmetry center of the longitudinal plate.

4. The L-shaped wave-breaking plate according to claim 3, characterized in that: The short axis length of the manhole is greater than the diameter of the liquid through hole, and the diameter of the liquid through hole is greater than the diameter of the air vent.

5. The L-shaped wave-breaking plate according to claim 1, characterized in that: It also includes a wave-breaking plate reinforcement ring, which is fixed to the edges of the transverse plate, the arc plate and the longitudinal plate.

6. The L-shaped wave-breaking plate according to claim 1, characterized in that: It also includes a liquid through hole reinforcement ring, which is fixed to the circumferential edge of the liquid through hole.

7. The L-shaped wave-breaking plate according to claim 1, characterized in that: It also includes a manhole reinforcement ring, which is fixed to the circumferential edge of the manhole.

8. A method for optimizing the design of an L-shaped wave-breaking plate, characterized in that: The method is used to design the L-shaped wave-breaking plate described in any one of claims 1 to 7 above, and a response surface approximate model of the design variables of the L-shaped wave-breaking plate and the liquid sloshing response of the tank truck is constructed by the finite element method and the response surface method, and a mathematical model of the multi-objective optimization problem of the L-shaped wave-breaking plate is constructed. The mathematical model is solved by using an improved non-dominated sorting genetic algorithm (NSGA-III) with an elite strategy to obtain a Pareto optimal solution set, and finally the finite element method is used to perform a fluid-solid coupling experiment to determine the optimal design parameter combination of the L-shaped wave-breaking plate.

9. The L-shaped wave-breaking board design optimization method according to claim 8, characterized in that: The steps include: Step 1: parametrically model the L-shaped wave-breaking plate, complete the parametric modeling of the L-shaped wave-breaking plate and construct the geometric model of the tank truck body in SolidWorks; Step 2: Use the control variable method to conduct a single factor experiment on the design parameters of the L-shaped wave-breaking plate, obtain the liquid sloshing response of each design scheme through numerical simulation experiments, analyze the influence of the design parameters on the liquid sloshing response, and preliminarily narrow the value range of each design parameter; Step 3, through the Plackett-Burman experiment, the significant factors affecting the longitudinal impact force of the liquid during the braking process of the tank truck, the force on the first wave-breaking board, and the roll moment during the turning process are screened out; Step 4, using the steepest climbing test to determine the high level, medium level and low level of the design parameters of the L-shaped wave-breaking board; Step 5, using Box-Behnken design to determine the design scheme, and obtaining the liquid sloshing response of each design scheme through numerical simulation experiments; taking the horizontal axis a and the vertical axis b of the manhole on the longitudinal plate of the L-shaped wave-breaking plate, the horizontal offset distance c of the manhole, and the vertical offset distance d of the manhole as independent variables, and taking the peak value F1 of the longitudinal impact force of the liquid during the braking process of the tank truck, the peak force F2 of the first wave-breaking plate, and the peak value M of the rolling moment of the tank truck during the turning process as dependent variables, using the least squares method to fit the quadratic polynomial to determine the regression equations of the three liquid sloshing responses of the L-shaped wave-breaking plate; the basic form of the second-order polynomial regression equations of the three liquid sloshing responses of the L-shaped wave-breaking plate is: Where: is the number of design parameters; is the intercept term; Indicates design parameters The linear effect of Indicates design parameters and The linear interaction effect of Design parameters The quadratic linear effect of represents the random error term; Step 6, evaluate the regression equation; Calculate the root mean square error (RMSE), coefficient of variation (CV), and coefficient of determination (R-Square) of the regression equations of the three liquid sloshing responses of the L-shaped wave-breaking plate respectively. If the root mean square error of the regression equation is less than 0.5, the coefficient of variation is less than 10%, and the coefficient of determination is greater than 95%, then execute step 7. Otherwise, check the distribution diagram of the predicted value and the actual value, re-conduct the numerical simulation experiment for the points with large deviations, and return to step 5 until the evaluation indicators of the regression equation meet the above requirements. Step 7, taking the transverse axis a and the longitudinal axis b of the manhole on the longitudinal plate of the L-shaped wave-breaking plate, the horizontal offset distance c of the manhole and the vertical offset distance d of the manhole as design variables, taking the peak longitudinal impact force F1 of the liquid during the braking process of the tank truck, the peak force F2 of the first wave-breaking plate, the peak roll moment M of the tank truck during the turning process and the mass m of the L-shaped wave-breaking plate as optimization targets, taking the value range of the design parameters of the L-shaped wave-breaking plate determined by the steepest climbing experiment as constraint conditions, the mathematical model of the multi-objective optimization problem of the L-shaped wave-breaking plate is: Step 8, according to the established mathematical model of the multi-objective optimization problem of the L-shaped wave-breaking plate, the improved non-dominated sorting genetic algorithm NSGA-Ⅲ with elite strategy is used to solve the mathematical model and obtain the Pareto optimal solution set; Step 9: Conduct fluid-solid coupling experiments on the tank truck under braking and turning conditions based on the Pareto optimal solution set, select the design parameter combination in which the overall force of the tank truck body meets the design requirements and all evaluation indicators of the wave-breaking plate reach a relatively low level as the Pareto optimal solution, output the Pareto optimal solution, and use it as the optimal design parameter combination for the L-shaped wave-breaking plate.

10. The L-shaped wave-breaking board design optimization method according to claim 9, characterized in that: The regression equations of the three liquid sloshing responses of the L-shaped wave-breaking plate in step 5 are: 1) The regression equation of the peak value F1 of the longitudinal impact force of the liquid when the tank truck is braked is: 2) The regression equation of the peak force F2 of the first wave-breaking plate when the tank truck is braked is: 3) The regression equation of the peak value M of the rolling moment when the tank truck turns is: 。

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