Method, device and equipment for selecting void diameter ratio of ship shafting and medium

Abstract

The invention relates to a ship shafting air-diameter ratio selection method, device, equipment and medium, and belongs to the technical field of ships, the ship shafting air-diameter ratio selection method comprises the steps of obtaining a plurality of ship shafting models which are constructed based on hollow design and consider the relation between shafting weight reduction mass and the air-diameter ratio, conducting strength performance checking on the ship shafting models, and obtaining the air-diameter ratio of the ship shafting. The strength stress of the ship shafting is obtained, and strength performance parameters are determined; dynamic characteristic checking is carried out on the ship shafting model based on the strength stress of the ship shafting, and vibration performance parameters and shock resistance parameters are determined; and based on the strength performance parameters, the vibration performance parameters and the shock resistance parameters, the optimal air-diameter ratio is determined by adopting a multi-objective optimization method, and the maximum lightweight degree and the optimal performance of the shaft system are realized.

Description

Technical Field

[0001] The present invention relates to the field of ship technology, and in particular to a method, device, equipment and medium for selecting the hollow-to-diameter ratio of a ship shaft system. Background Art

[0002] The ship's propulsion shaft system is a connection structure between the main engine and the propeller. The power from the main engine is transmitted to the propeller end through the shaft system. The rotation of the propeller generates a reaction force on the hull, pushing the ship forward.

[0003] For the lightweight design of ship shafting, on the one hand, advanced composite materials can be used, and on the other hand, the shafting structure can be hollowed out. With the development of larger ships, most ships currently use solid shafts. Hollowing out the shafting can effectively achieve lightweight shafts. In the design of hollow shafts of ships and the selection of the hollow-to-diameter ratio, the hollow-to-diameter ratio is mainly selected based on the strength characteristics of the shafting.

[0004] However, the shaft system's air-to-diameter ratio is selected based on the strength characteristics of the shaft system. Although the selected shaft system's air-to-diameter ratio has higher safety in terms of strength, it does not take into account the shaft system's vibration characteristics and impact resistance requirements, and cannot achieve the goal of maximum shaft system lightweighting and optimal performance. Summary of the invention

[0005] In view of this, it is necessary to provide a method, device, equipment and medium for selecting the hollow-to-diameter ratio of a ship shaft system, so as to solve the technical problem that when designing the lightweight design of a ship shaft system, only the strength characteristics are considered but the vibration characteristics and impact resistance requirements of the shaft system are not considered, and the maximum lightweight degree and optimal performance of the shaft system cannot be achieved.

[0006] In order to solve the above problems, the present invention provides a method for selecting the space-to-diameter ratio of a ship shaft system, comprising: Acquire multiple ship shafting models based on hollow design and taking into account the relationship between shafting weight reduction and hollow-diameter ratio, perform strength performance verification on the ship shafting models, obtain strength stress of the ship shafting, and determine strength performance parameters; Performing a dynamic characteristic check on the ship shafting model based on the strength stress of the ship shafting to determine vibration performance parameters and impact resistance performance parameters; Based on the strength performance parameters, vibration performance parameters and impact resistance performance parameters, a multi-objective optimization method is used to determine the optimal air-to-diameter ratio.

[0007] In a possible implementation, the step of obtaining multiple ship shafting models based on hollow design and taking into account the relationship between shafting weight reduction and hollow-diameter ratio includes: Determine the range of air-to-diameter ratio; Based on the range of the space-to-diameter ratio, multiple ship shafting models are constructed that consider the relationship between the shafting weight reduction mass and the space-to-diameter ratio.

[0008] In a possible implementation, the calculation formula for the relationship between the shaft system weight reduction mass and the air-to-diameter ratio is: , in, The weight reduction of the ship shaft system, is the shaft material density, is the air diameter ratio, is the shaft diameter, is the shaft diameter, is the axis length.

[0009] In a possible implementation, the performing strength performance verification on the ship shafting model to obtain the strength stress of the ship shafting includes: Presetting a void-to-diameter ratio threshold value to determine the void-to-diameter ratio of the ship shafting model; When the space-to-diameter ratio is greater than the space-to-diameter ratio threshold, adjusting the outer diameter of the ship shaft system to obtain a corrected outer diameter of the ship shaft system; Performing strength performance verification on the ship shafting model based on the corrected outer diameter of the ship shafting to obtain strength stress of the ship shafting; When the void-diameter ratio is less than or equal to the void-diameter ratio threshold, the ship shafting model is subjected to strength performance verification to obtain the strength stress of the ship shafting, wherein the strength stress of the ship shafting includes the axial stress of the shafting, the shear stress of the shafting, the bending stress of the shafting, and the equivalent stress of the shafting; The allowable stress of the shafting material is determined. When the strength stress of the ship shafting is greater than the allowable stress of the shafting material, the aperture ratio is adjusted within the aperture ratio range so that the strength stress of the ship shafting is less than or equal to the allowable stress of the shafting material.

[0010] In a possible implementation, the calculation formula for the corrected outer diameter of the ship shafting is: , , in, is the corrected outer diameter of the ship shaft system, is the shaft diameter, is the shaft aperture; The calculation formula of the axial stress of the shaft system is: , in, is the axial stress of the shaft system, is the propeller thrust, is the cross-sectional area; The calculation formula of the shear stress of the shaft system is: , in, is the bending stress of the shaft system, is the rotational moment on the shaft section, is the torsional section modulus; The calculation formula of the bending stress of the shaft system is: , in, is the bending stress of the shaft system, is the bending moment on the axial section, is the bending section modulus; The calculation formula for the equivalent stress of the shaft system is: , in, is the equivalent stress of the shaft system.

[0011] In a possible implementation, the dynamic characteristic verification of the ship shafting model based on the strength stress of the ship shafting to obtain vibration performance parameters and shock resistance performance parameters includes: When the strength stress of the ship shafting is less than or equal to the allowable stress of the shafting material, the ship shafting model is subjected to dynamic characteristic verification to determine vibration performance parameters and impact resistance performance parameters, wherein the dynamic characteristics include the vibration characteristics and impact resistance characteristics of the shafting, the vibration performance parameters include torsional vibration parameters, whirling vibration parameters and longitudinal vibration performance parameters, and the impact resistance performance parameters include impact resistance stress parameters; The allowable stress of the ship shafting and the maximum impact stress of the ship shafting are determined. When the maximum impact stress is greater than the allowable stress, the aperture ratio is adjusted within the aperture ratio range so that the maximum impact stress of the ship shafting is less than or equal to the allowable stress of the ship shafting.

[0012] In a possible implementation, the optimal air-to-diameter ratio is determined by using a multi-objective optimization method based on the strength performance parameter, the vibration performance parameter, and the impact resistance performance parameter, including: Determining the weight reduction of the shaft system based on the strength performance parameter and the air-to-diameter ratio; Determining the torsion angle of the shaft system based on the vibration performance parameter and the air-to-diameter ratio; Determining the impact stress of the shaft system based on the impact resistance performance parameter and the air-to-diameter ratio; The optimization objectives are to maximize the weight reduction mass, minimize the impact stress, and minimize the torsion angle, the shaft system's air-to-diameter ratio is used as the independent variable, the torsion angle and impact stress are used as the dependent variables, and a multi-objective optimization method is used to determine the optimal air-to-diameter ratio.

[0013] On the other hand, the present invention also provides a device for selecting the space-to-diameter ratio of a ship shaft system, comprising: A strength performance verification module is used to obtain multiple ship shafting models based on hollow design that consider the relationship between shafting weight reduction and hollow-diameter ratio, perform strength performance verification on the ship shafting models, obtain the strength stress of the ship shafting, and determine the strength performance parameters; A dynamic characteristic verification module, used to perform dynamic characteristic verification on the ship shafting model based on the strength stress of the ship shafting, and determine vibration performance parameters and anti-shock performance parameters; The optimal air-to-diameter ratio determination module is used to determine the optimal air-to-diameter ratio by using a multi-objective optimization method based on the strength performance parameters, vibration performance parameters and impact resistance performance parameters.

[0014] In another aspect, the present invention further provides an electronic device, comprising: a processor and a memory; The memory stores a computer-readable program executable by the processor; When the processor executes the computer-readable program, the steps in the method for selecting the space-to-diameter ratio of a ship shafting as described above are implemented.

[0015] On the other hand, the present invention also provides a computer-readable storage medium, which stores one or more programs, and the one or more programs can be executed by one or more processors to implement the steps in the ship shafting diameter ratio selection method as described above.

[0016] The beneficial effects of the present invention are as follows: a plurality of ship shafting models are constructed to provide a basis for strength performance verification and dynamic characteristic verification, the strength performance verification of the ship shafting model is carried out so that the selected air-to-diameter ratio can meet the strength performance of the shafting, the dynamic characteristic verification of the ship shafting model is carried out based on the strength stress of the ship shafting, after the shafting meets the strength performance requirements, the dynamic characteristic verification of the ship shafting model is carried out so that the selected air-to-diameter ratio can meet the dynamic characteristic requirements of the shafting, the impact resistance of the shafting is effectively improved, the optimal air-to-diameter ratio is determined by a multi-objective optimization method, the strength performance parameters, the vibration performance parameters and the impact resistance performance parameters are taken as optimization targets, and the optimal air-to-diameter ratio is further selected by using a multi-objective optimization algorithm, so as to achieve the maximum lightweight degree and the optimal performance of the shafting. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 A flow chart of an embodiment of a method for selecting the hollow-to-diameter ratio of a ship shaft system provided by the present invention; Figure 2 A schematic diagram of a hollow shaft for selecting the hollow-diameter ratio of a ship shaft system provided by the present invention; Figure 3A schematic structural diagram of an embodiment of a device for selecting the hollow-to-diameter ratio of a ship shaft system provided by the present invention; Figure 4 A schematic structural diagram of an embodiment of an electronic device provided by the present invention. DETAILED DESCRIPTION

[0018] The preferred embodiments of the present invention are described in detail below in conjunction with the accompanying drawings, wherein the accompanying drawings constitute a part of this application and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not used to limit the scope of the present invention.

[0019] The present invention discloses a method, device, equipment and medium for selecting the hollow-diameter ratio of a ship shaft system, which can be used in a computer. The method, device or computer-readable storage medium involved in the present invention can be integrated with the above-mentioned device or can be relatively independent.

[0020] A specific embodiment of the present invention discloses a method for selecting the space-to-diameter ratio of a ship shaft system, which can be executed by a computer, specifically by one or more processors of the computer. Figure 1 This is a flow chart of the method for selecting the hollow diameter ratio of a ship shaft system provided by an embodiment of the present invention. Figure 1 , the methods for selecting the ship shafting diameter ratio include: S101, obtaining multiple ship shafting models based on hollow design and considering the relationship between shafting weight reduction and hollow-diameter ratio, performing strength performance verification on the ship shafting models, obtaining strength stress of the ship shafting, and determining strength performance parameters; S102, checking the dynamic characteristics of the ship shafting model based on the strength stress of the ship shafting, and determining vibration performance parameters and impact resistance performance parameters; S103. Based on the strength performance parameters, vibration performance parameters and impact resistance performance parameters, a multi-objective optimization method is used to determine the optimal air-to-diameter ratio.

[0021] Among them, multiple ship shafting models considering the relationship between the shafting weight reduction and the air-to-diameter ratio are constructed, that is, ship shafting models with different air-to-diameter ratios are constructed, and the strength performance of the ship shafting models is checked. By adjusting the air-to-diameter ratio, the strength performance of the ship shafting does not exceed the maximum allowable stress and meets the strength performance requirements. The multi-objective optimization method is used to determine the optimal air-to-diameter ratio, and the NSGA-Ⅱ multi-objective optimization algorithm is used to further select the optimal air-to-diameter ratio.

[0022] Compared with the prior art, the method for selecting the hollow-diameter ratio of a ship shaft system provided in this embodiment obtains multiple ship shaft system models based on hollow design that consider the relationship between the shaft system weight reduction mass and the hollow-diameter ratio, provides a basis for strength performance verification and dynamic characteristic verification, performs strength performance verification on the ship shaft system model, obtains the strength stress of the ship shaft system, and determines the strength performance parameters, so that the selected hollow-diameter ratio can meet the strength performance of the shaft system, performs dynamic characteristic verification on the ship shaft system model based on the strength stress of the ship shaft system, determines the vibration performance parameters and the impact resistance performance parameters, after the strength stress of the shaft system meets the strength performance requirements, performs dynamic characteristic verification on the ship shaft system model, so that the selected hollow-diameter ratio can meet the dynamic characteristic requirements of the shaft system, effectively improves the impact resistance of the shaft system, and determines the optimal hollow-diameter ratio based on the strength performance parameters, vibration performance parameters and impact resistance performance parameters. The hollow-diameter ratio is used as an independent variable, and the strength performance parameters, vibration performance parameters and impact resistance performance parameters are used as optimization targets. The optimal hollow-diameter ratio is further selected using the multi-objective optimization algorithm to achieve the maximum lightweight degree and the best performance of the shaft system.

[0023] In some embodiments, in step S101, in order to meet the lightweight requirements of the ship shaft system and reduce the weight of the shaft system to improve the propulsion performance of the ship shaft system, the ship shaft system is hollow-designed. For a schematic diagram of the hollow shaft, please refer to Figure 2 ,like Figure 2 As shown, is the shaft diameter, is the shaft diameter, is the outer diameter of the shaft after expansion, is the shaft length; determine the range of the air-to-diameter ratio, the range of the air-to-diameter ratio is Based on the range of the air-diameter ratio, multiple ship shafting models considering the relationship between the shafting weight reduction mass and the air-diameter ratio are constructed. That is, within the range of the air-diameter ratio, multiple air-diameter ratios are selected according to the air-diameter ratio value density, that is, with the air-diameter ratio of 0.1 as an increment, multiple air-diameter ratios are selected within the range of the air-diameter ratio to construct 3D models of ship shafting with different air-diameter ratios. The 3D models of ship shafting with different air-diameter ratios are multiple ship shafting models considering the relationship between the shafting weight reduction mass and the air-diameter ratio. The larger the air-diameter ratio value density, the better. At this time, the amount of calculation is large, but there are more results, which is conducive to solving the optimal air-diameter ratio. The calculation formula for the relationship between the shafting weight reduction mass and the air-diameter ratio is: , in, The weight reduction of the ship shaft system, is the shaft material density, is the air diameter ratio, is the shaft diameter, is the shaft diameter, is the shaft length, and the weight reduction of the shaft system is in a quadratic function relationship with the hollow diameter ratio; When the ship shaft system is hollow, the hollow structure will affect the strength of the shaft system. When the strength is affected too much, the outer diameter of the shaft needs to be revised. When it is greater than 0.4, the shaft outer diameter is recalculated and corrected to ensure that the ship shafting has sufficient strength; the ship shafting model is strength checked to obtain the strength stress of the ship shafting, and the strength performance parameters are determined, wherein the strength stress of the ship shafting includes the axial stress of the shafting, the shear stress of the shafting, the bending stress of the shafting and the equivalent stress of the shafting, and the strength performance parameters include the axial stress parameter, the shear stress parameter, the bending stress parameter and the equivalent stress parameter; firstly, a preset diameter ratio threshold is set to 0.4, and the diameter ratio of the ship shafting model is determined. When the diameter ratio of the ship shafting model is greater than the diameter ratio threshold of 0.4, the outer diameter of the ship shafting is adjusted to obtain the corrected outer diameter of the ship shafting , the corrected calculation formula for the outer diameter of the ship shafting is: , , in, is the corrected outer diameter of the ship shaft system, is the shaft diameter, is the shaft aperture. By changing the size of the outer diameter of the ship's shaft system, the size of its aperture ratio will also change; Secondly, when the void-diameter ratio is greater than the void-diameter ratio threshold, the strength performance of the ship shafting model is checked based on the corrected outer diameter of the ship shafting to obtain the strength stress of the ship shafting. When the void-diameter ratio is less than or equal to the void-diameter ratio threshold, the strength performance of the ship shafting model is checked to obtain the strength stress of the ship shafting. Finally, the allowable stress of the shafting material is determined, and the allowable stress is obtained through the yield limit of the shafting material and the safety factor of the shafting material. When the strength stress of the ship shafting is greater than the allowable stress of the shafting material, the void-diameter ratio is adjusted within the range of the void-diameter ratio, that is, the outer diameter of the ship shafting is corrected and checked. By expanding the outer diameter of the ship shafting, the strength stress of the ship shafting is less than or equal to the allowable stress of the shafting material, ensuring that the strength stress of the ship shafting does not exceed the allowable stress range of the shafting material, so as to weaken the influence of the void-diameter ratio on the strength of the shafting until the strength performance requirements of the shafting are met. The calculation formula of the axial stress of the shafting is: , , in, is the axial stress of the shaft system, is the propeller thrust, is the cross-sectional area; The calculation formula of the shear stress of the shaft system is: , in, is the bending stress of the shaft system, is the rotational moment on the shaft section, is the torsional section modulus; The calculation formula of the bending stress of the shaft system is: , in, is the bending stress of the shaft system, is the bending moment on the axial section, is the bending section modulus; The calculation formula of the equivalent stress of the shaft system under multiple loads is: , in, is the equivalent stress of the shafting system. If the load remains unchanged, the larger the value of the hollow-diameter ratio, the greater the axial stress, shear stress, bending stress and equivalent stress on the hollow shaft. That is, the stress of the solid shaft is less than that of the hollow shaft, resulting in the weakening of the hollow shaft strength due to the hollow-diameter ratio. The strength performance of the ship shafting model with different hollow-diameter ratios is checked. Its strength performance is a limiting condition for the reasonable application of the ship shafting system. The strength performance of the shafting system is measured based on the equivalent stress. When the hollow-diameter ratio is larger, the strength stress on the shafting system is greater, and the weight reduction of the shafting system is greater.

[0024] In some embodiments, in step S102, the hollow design will also affect the dynamic characteristics of the shaft system, and the dynamic characteristics include the vibration characteristics and impact resistance characteristics of the shaft system. Therefore, it is necessary to calibrate the vibration performance and impact resistance characteristics of the shaft system, and perform a dynamic characteristic calibration on the ship shaft system model based on the strength stress of the ship shaft system to determine the vibration performance parameters and impact resistance performance parameters. The vibration performance parameters include torsional vibration parameters, cyclotron vibration parameters and longitudinal vibration performance parameters, and the impact resistance performance parameters include impact resistance stress parameters. When the strength stress of the shaft system meets the strength performance requirements, that is, the strength stress of the ship shaft system is less than or equal to the allowable stress of the shaft system material, the ship shaft system model is dynamically calibrated. If the vibration and impact resistance performance of the shaft system cannot meet the requirements of the specification, the outer diameter is corrected, that is, the hollow-to-diameter ratio is adjusted until the dynamic characteristics requirements of the specification are met.

[0025] The Von-Mises failure theory is used to evaluate the impact resistance of the shafting system. The effective stress of each mode and the modal stress synthesized by the modal synthesis method should be less than the allowable stress. The effective stress of each mode is obtained by the NRL (United States Naval Research Laboratory) method, and the calculation formula is: , in, is the Von-Mises dynamic stress at node mode a, is the maximum value of Von-Mises dynamic stress of all modes of the node, is the effective dynamic stress of the node, the total stress is the sum of the absolute values ​​of the working stress and the effective impact dynamic stress, and the total stress corresponds to the maximum impact stress of the ship shafting. The calculation formula is: , in, is the Von-Mises working stress of node mode a; Determine the allowable stress of the ship shafting. When the maximum impact stress is greater than the allowable stress, adjust the outer diameter of the ship shafting and the void-to-diameter ratio within the void-to-diameter ratio range to make the maximum impact stress of the ship shafting less than or equal to the allowable stress of the ship shafting. The smaller the maximum impact stress, the better the performance of the shafting.

[0026] The free torsional vibration of the shafting model with different air-diameter ratios is calculated. By calculating the torsional vibration stress and the torsion angle, it is judged whether the allowable stress exceeds the safety range. First, the ROTX degree of freedom of the bearing is set to an unconstrained condition, and the other degrees of freedom of the bearing are set to displacement constraints. A uniformly distributed gravity load is applied to the shaft segment to obtain the first-order natural frequency of the shafting corresponding to each air-diameter ratio. Based on the solved first-order natural frequency, the corresponding load is applied to solve the torsional vibration stress of the stern shaft and propeller at the first-order natural frequency with different air-diameter ratios, and the maximum torsional vibration stress is obtained. The maximum torsional vibration stress is less than the allowable torsional vibration stress; the torsion angle of each key part of the model with different air-diameter ratio is calculated, and the torsion angle in the opposite direction is not considered, and only the absolute value is taken. With the increase of the air-diameter ratio, the maximum torsion angle of the shafting first decreases gradually and then increases gradually. The outer diameter of the shafting before and after correction and the maximum torsion angle of the shafting remain unchanged, that is, the outer diameter correction has no effect on the torsion angle.

[0027] In some embodiments, in step S103, based on the strength performance parameters, vibration performance parameters and impact resistance performance parameters, a multi-objective optimization method is used to determine the optimal air-to-diameter ratio. By performing a strength performance check on the ship shafting model, it can be seen that the larger the air-to-diameter ratio, the smaller the shafting mass, but the greater the strength stress. By performing a dynamic characteristic check on the ship shafting model, it can be seen that the smaller the maximum torsion angle and the maximum impact stress, the better the performance of the shafting. The weight reduction mass of the ship shafting is determined by the strength performance parameters and the air-to-diameter ratio, and the weight reduction mass of the ship shafting is determined by the vibration performance parameters and the air-to-diameter ratio. The torsion angle of the ship shaft system is determined, and the impact stress of the shaft system is determined by the impact resistance parameters and the air-to-diameter ratio. Considering the lightweight degree and optimal performance of the shaft system, the optimization goals are to maximize the weight reduction, minimize the impact stress, and minimize the torsion angle. The air-to-diameter ratio of the shaft system is taken as the independent variable, and the torsion angle and impact stress are taken as the dependent variables. The multi-objective optimization method is used to determine the optimal air-to-diameter ratio. First, a polynomial function is constructed based on the torsion angle and impact stress. There is no obvious difference in the torsion angle before and after the shaft system is corrected. Only a torsion angle polynomial function needs to be fitted. The calculation formula of the polynomial function is: , in, is the torsion angle polynomial fitting function, To correct the polynomial fitting function of the impact stress before the outer diameter, The polynomial fitting function of impact stress after correcting the outer diameter is: is the decision variable, i.e., the air-to-diameter ratio; Based on the polynomial function, the NSGA-Ⅱ multi-objective genetic algorithm is used to obtain the Pareto optimal solution of the air-to-diameter ratio. The calculation formula is: , in, is the target variable, the target space is Y, the decision space is X, the decision space X is the range of the air-to-air ratio 0.0-0.8, the set of all Pareto optimal solutions is the Pareto solution set, and the projection of all Pareto solution sets in the target space is the Pareto frontier, which is calculated as follows: , in, is the Pareto frontier, is the Pareto solution set, with the air-to-diameter ratio as the decision variable , decision space is 0.0-0.8, torsion angle and impact stress are target vectors , the minimum to maximum value of the two is the target space , the boundary condition is that the impact stress does not exceed the allowable stress, and the optimal air-to-diameter ratio is determined by extracting the optimal decision variables through the Pareto front.

[0028] In some embodiments, the finite element analysis method is used to analyze the strength performance, vibration performance and impact resistance of the shaft system. The shaft system of a ship is taken as the object. The material of the shaft system is 45 steel, the density is 7850kg / m3, and the Young's modulus is Pa, Poisson's ratio is 0.31, yield strength is 355MPa, the shaft system is designed to be hollow, and the hollow diameter ratio is selected within the hollow diameter ratio range. When the hollow diameter ratio is 0.5-0.8, according to the specification requirements, the outer diameter of the shaft system needs to be corrected to design 13 ship shaft system models, calculate the inner diameter, outer diameter and mass of the shaft system, and the calculation results are shown in Table 1. Table 1

[0029] As shown in Table 1, the hollow design of the shaft system can reduce the mass of the shaft system. According to the strength requirements in the specification, its strength will be affected. Taking the shaft system with a hollow-diameter ratio of 0.8 as an example, the strength calculation is performed using the finite element method. The friction coefficient at the connection between the thrust bearing and the intermediate bearing and the shaft system is set to 0.02. The front and rear suspension stern bearings use compression support only. The load borne by the shaft system includes thrust and torque. The experience time is 10s. The thrust increases uniformly from 500kN to 750kN, and the torque increases uniformly from 500N to 1000kN. m increases at a constant speed to 750N m, the maximum equivalent stress on the shaft at the connection between the stern shaft and the intermediate shaft is 237.24Mpa, and the corresponding minimum safety factor is 1.50, which does not exceed the material yield limit of 355Mpa. When the air-to-diameter ratio is 0.8, the shaft load cross-sectional area is the smallest, the equivalent stress of the model is the largest, and the safety factor is the smallest, but it does not exceed the material limit and meets the strength requirements. That is, when the air-to-diameter ratio is 0.8, the shafting strength is safe.

[0030] The vibration performance is analyzed. When the air-diameter ratio is 0.1, the natural frequency value is the largest, and its frequency is 9.886Hz. When the air-diameter ratio is between 0.5 and 0.7, the natural frequency of the shaft system changes little before and after the outer diameter correction. When the air-diameter ratio is 0.8, the first-order natural frequency of the shaft system changes more before and after the outer diameter correction. Based on the solved first-order natural frequency, 20 nodes are taken within its 1 / 6 frequency band, and the corresponding load is applied to calculate the torsional vibration stress of the stern shaft and propeller at the first-order natural frequency with different air-diameter ratios. The maximum torsional vibration stress of the models with different air-diameter ratios is different. The size of the air-diameter ratio affects the vibration response and stress distribution of the shaft system. The maximum torsional vibration stresses in the stern shaft and propeller parts all appear at the first-order natural frequency and are concentrated near the front and rear stern bearings. Among all the air-to-diameter ratios, when the air-to-diameter ratio is 0.6, the maximum torsional vibration stress in the propeller part of the shaft system is 1.38Mpa, which is less than the allowable torsional vibration stress. Compared with before the correction, the torsional vibration stress of the shaft system after the correction is smaller. With the increase of the air-to-diameter ratio, the maximum torsion angle of the shaft system first gradually decreases, reaching the minimum at the air-to-diameter ratio of 0.6, with a torsion angle of 1.002×10-2°, and then gradually increases. Between the air-to-diameter ratio of 0.0-0.4, the maximum torsion angle appears in the intermediate shaft, and when the air-to-diameter ratio is greater than 0.4, it appears in the stern shaft. The maximum torsion angle of the shaft system remains unchanged before and after the correction, that is, whether the outer diameter is corrected or not has no effect on the torsion angle.

[0031] The dynamic design analysis method is used to analyze the anti-impact performance of the shaft system. The result is obtained by superimposing the response peaks generated by each mode, which is larger than the actual situation. The impact of the impact load on the shaft system is expressed in the form of an impact spectrum. In order to ensure the accuracy of the results and the integrity of the modal information, it is necessary to analyze enough vibration modes to ensure that the total modal mass is not less than 80% of the total mass of the system; the acceleration of the shaft system impact spectrum is obtained by the effective modal mass obtained by modal analysis, and its calculation formula is: , , in, is the acceleration, is the acceleration, The effective modal mass is determined. After determining the impact coefficients in the vertical, horizontal, and longitudinal directions, the effective modal mass greater than 1% in the first 100 modes is substituted into the above formula to calculate the standard acceleration. And table acceleration , taking the impact acceleration as the input condition, the equivalent stress is obtained. The maximum equivalent stress of the solid shaft is located on the propeller, and the stress is 339.04Mpa, which does not exceed the yield strength of the material, proving that the shaft has good impact resistance. Under the same impact conditions, the maximum impact stress of the shaft system is concentrated on the intermediate shaft and the propeller, and the maximum impact stress of the stern shaft and the thrust shaft is relatively small. When the air-to-diameter ratio is 0.7, the maximum impact stress of the shaft system appears in the intermediate shaft, and the stress value is 376.78Mpa, which differs by 40.36Mpa from the impact stress of the shaft system with the corrected air-to-diameter ratio of 0.7, and exceeds the yield limit of the shaft system; when the air-to-diameter ratio is 0.5, the maximum impact stress of the shaft system is the smallest, with a stress of 317.53Mpa, which does not exceed the yield limit of the shaft system.

[0032] Compared with the impact stress of the solid shaft, the maximum impact stress of the hollow shaft with an air-to-diameter ratio of 0.4-0.6 is smaller than the corresponding stress of the solid shaft. The stress of the corrected shaft system is smaller than the corresponding stress of the solid shaft within a certain air-to-diameter ratio range, indicating that the impact resistance of the hollow shaft is better than that of the solid shaft within a specific range.

[0033] The Pareto optimal solution of the air-to-diameter ratio is determined by the NSGA-Ⅱ multi-objective genetic algorithm. The optimal decision variables extracted by the Pareto frontier determine the optimal air-to-diameter ratio to be 0.649 and 0.788, corresponding to the objective function value That is, the torsion angles are ° and °, corrected front impact stress 343.96Mpa, corrected impact stress It is 322.58Mpa. Compared with the solid shaft, the hollow shaft corresponding to the optimal air-to-diameter ratio before and after correction is reduced by about 28t and 40t respectively.

[0034] In order to better implement the method for selecting the ship shafting diameter ratio in the embodiment of the present invention, based on the method for selecting the ship shafting diameter ratio, correspondingly, Figure 3 As shown, the embodiment of the present invention further provides a device for selecting the space-to-diameter ratio of a ship shaft system. The device 300 for selecting the space-to-diameter ratio of a ship shaft system includes: The strength performance verification module 301 is used to obtain multiple ship shafting models based on hollow design and considering the relationship between shafting weight reduction and hollow diameter ratio, perform strength performance verification on the ship shafting models, obtain the strength stress of the ship shafting, and determine the strength performance parameters; A dynamic characteristic checking module 302 is used to check the dynamic characteristics of the ship shafting model based on the strength stress of the ship shafting, and determine the vibration performance parameters and the anti-shock performance parameters; The optimal air-to-diameter ratio determination module 303 is used to determine the optimal air-to-diameter ratio by adopting a multi-objective optimization method based on strength performance parameters, vibration performance parameters and impact resistance performance parameters.

[0035] like Figure 4 As shown, based on the method for selecting the space-to-diameter ratio of a ship shaft system, the present invention also provides an electronic device 400, which can be a computing device such as a mobile terminal, a desktop computer, a notebook, a palm computer, and a server. The electronic device 400 includes a processor 401, a memory 402, and a display 403. Figure 4 Only some components of the electronic device 400 are shown, but it should be understood that it is not required to implement all of the components shown, and more or fewer components may be implemented instead.

[0036] In some embodiments, the memory 402 may be an internal storage unit of the electronic device 400, such as a hard disk or memory of the electronic device 400. In other embodiments, the memory 402 may also be an external storage device of the electronic device 400, such as a plug-in hard disk, a smart media card (SMC), a secure digital (SD) card, a flash card, etc. equipped on the electronic device 400. Further, the memory 402 may also include both an internal storage unit and an external storage device of the electronic device 400. The memory 402 is used to store application software and various data installed in the electronic device 400, such as program codes for installing the electronic device 400. The memory 402 may also be used to temporarily store data that has been output or is to be output. In one embodiment, a ship shafting diameter ratio selection program is stored on the memory 402, and the ship shafting diameter ratio selection program can be executed by the processor 401, thereby realizing the ship shafting diameter ratio selection method of each embodiment of the present invention.

[0037] In some embodiments, the processor 401 may be a central processing unit (CPU), a microprocessor or other data processing chip, which is used to run program codes or process data stored in the memory 402, such as a method for selecting a ship shafting diameter ratio.

[0038] In some embodiments, the display 403 may be an LED display, a liquid crystal display, a touch-sensitive liquid crystal display, an OLED (Organic Light-Emitting Diode) touch device, etc. The display 403 is used to display identification information of the ship shafting air-diameter ratio selection program and to display a visual user interface. The components 401-403 of the electronic device 400 communicate with each other via a system bus.

[0039] In some embodiments, when the processor 401 executes the ship shafting clearance ratio selection program in the memory 402, the various steps in the ship shafting clearance ratio selection method described in the above embodiments are implemented. Since the ship shafting clearance ratio selection method has been described in detail above, it will not be repeated here.

[0040] Accordingly, an embodiment of the present application also provides a computer-readable storage medium, which is used to store computer-readable programs or instructions. When the program or instructions are executed by a processor, the steps or functions in the ship shaft system air-to-diameter ratio selection method provided in the above-mentioned method embodiments can be implemented.

[0041] In summary, the method, device, equipment and medium for selecting the hollow-to-diameter ratio of a ship shafting system provided by the present invention obtain multiple ship shafting models based on hollow design that consider the relationship between the shafting weight reduction mass and the hollow-to-diameter ratio, perform strength performance verification on the ship shafting model, obtain the strength stress of the ship shafting system, and determine the strength performance parameters; perform dynamic characteristic verification on the ship shafting model based on the strength stress of the ship shafting system, and determine the vibration performance parameters and the impact resistance performance parameters; based on the strength performance parameters, the vibration performance parameters and the impact resistance performance parameters, a multi-objective optimization method is used to determine the optimal hollow-to-diameter ratio, thereby achieving the maximum lightweight degree and optimal performance of the shafting system.

[0042] Those skilled in the art will appreciate that all or part of the processes of the above-mentioned embodiments can be implemented by instructing related hardware through a computer program, and the program can be stored in a computer-readable storage medium, wherein the computer-readable storage medium is a disk, an optical disk, a read-only storage memory, or a random access memory, etc.

[0043] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by any technician familiar with the technical field within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention.

Claims

1. A method for selecting the hollow-diameter ratio of a ship shaft system, characterized in that: include: Acquire multiple ship shafting models based on hollow design and taking into account the relationship between shafting weight reduction and hollow-diameter ratio, perform strength performance verification on the ship shafting models, obtain strength stress of the ship shafting, and determine strength performance parameters; Performing a dynamic characteristic check on the ship shafting model based on the strength stress of the ship shafting to determine vibration performance parameters and impact resistance performance parameters; Based on the strength performance parameters, vibration performance parameters and impact resistance performance parameters, a multi-objective optimization method is used to determine the optimal air-to-diameter ratio.

2. The method for selecting the hollow-diameter ratio of a ship shaft system according to claim 1, characterized in that: The method of obtaining multiple ship shafting models based on hollow design and taking into account the relationship between shafting weight reduction and hollow-diameter ratio comprises: Determine the range of air-to-diameter ratio; Based on the range of the space-to-diameter ratio, multiple ship shafting models are constructed that consider the relationship between the shafting weight reduction mass and the space-to-diameter ratio.

3. The method for selecting the hollow-diameter ratio of a ship shaft system according to claim 2, characterized in that: The calculation formula for the relationship between the shaft system weight reduction mass and the air-to-diameter ratio is: ， in, The weight reduction of the ship shaft system, is the shaft material density, is the air diameter ratio, is the shaft diameter, is the shaft diameter, is the axis length.

4. The method for selecting the hollow-diameter ratio of a ship shaft system according to claim 2, characterized in that: The checking the strength performance of the ship shafting model to obtain the strength stress of the ship shafting includes: Presetting a void-to-diameter ratio threshold value to determine the void-to-diameter ratio of the ship shafting model; When the space-to-diameter ratio is greater than the space-to-diameter ratio threshold, adjusting the outer diameter of the ship shaft system to obtain a corrected outer diameter of the ship shaft system; Performing strength performance verification on the ship shafting model based on the corrected outer diameter of the ship shafting to obtain strength stress of the ship shafting; When the void-diameter ratio is less than or equal to the void-diameter ratio threshold, the ship shafting model is subjected to strength performance verification to obtain the strength stress of the ship shafting, wherein the strength stress of the ship shafting includes the axial stress of the shafting, the shear stress of the shafting, the bending stress of the shafting, and the equivalent stress of the shafting; The allowable stress of the shafting material is determined. When the strength stress of the ship shafting is greater than the allowable stress of the shafting material, the aperture ratio is adjusted within the aperture ratio range so that the strength stress of the ship shafting is less than or equal to the allowable stress of the shafting material.

5. The method for selecting the hollow-diameter ratio of a ship shaft system according to claim 4, characterized in that: The calculation formula of the corrected outer diameter of the ship shafting is: ， ， in, is the corrected outer diameter of the ship shaft system, is the shaft diameter, is the shaft aperture; The calculation formula of the axial stress of the shaft system is: ， in, is the axial stress of the shaft system, is the propeller thrust, is the cross-sectional area; The calculation formula of the shear stress of the shaft system is: ， in, is the bending stress of the shaft system, is the rotational moment on the shaft section, is the torsional section modulus; The calculation formula of the bending stress of the shaft system is: ， in, is the bending stress of the shaft system, is the bending moment on the axial section, is the bending section modulus; The calculation formula for the equivalent stress of the shaft system is: ， in, is the equivalent stress of the shaft system.

6. The method for selecting the hollow-diameter ratio of a ship shaft system according to claim 4, characterized in that: The dynamic characteristic verification of the ship shafting model based on the strength stress of the ship shafting to obtain vibration performance parameters and shock resistance performance parameters includes: When the strength stress of the ship shafting is less than or equal to the allowable stress of the shafting material, the ship shafting model is subjected to dynamic characteristic verification to determine vibration performance parameters and impact resistance performance parameters, wherein the dynamic characteristics include the vibration characteristics and impact resistance characteristics of the shafting, the vibration performance parameters include torsional vibration parameters, whirling vibration parameters and longitudinal vibration performance parameters, and the impact resistance performance parameters include impact resistance stress parameters; The allowable stress of the ship shafting and the maximum impact stress of the ship shafting are determined. When the maximum impact stress is greater than the allowable stress, the aperture ratio is adjusted within the aperture ratio range so that the maximum impact stress of the ship shafting is less than or equal to the allowable stress of the ship shafting.

7. The method for selecting the space-to-diameter ratio of a ship shaft system according to claim 6, characterized in that: The method of determining the optimal air-to-diameter ratio by using a multi-objective optimization method based on the strength performance parameter, the vibration performance parameter and the impact resistance performance parameter includes: Determining the weight reduction of the shaft system based on the strength performance parameter and the air-to-diameter ratio; Determining the torsion angle of the shaft system based on the vibration performance parameter and the air-to-diameter ratio; Determining the impact stress of the shaft system based on the impact resistance performance parameter and the air-to-diameter ratio; The optimization objectives are to maximize the weight reduction mass, minimize the impact stress, and minimize the torsion angle, the shaft system's air-to-diameter ratio is used as the independent variable, the torsion angle and impact stress are used as the dependent variables, and a multi-objective optimization method is used to determine the optimal air-to-diameter ratio.

8. A device for selecting the ratio of the shafting diameter of a ship, characterized in that: include: A strength performance verification module is used to obtain multiple ship shafting models based on hollow design that consider the relationship between shafting weight reduction and hollow-diameter ratio, perform strength performance verification on the ship shafting models, obtain the strength stress of the ship shafting, and determine the strength performance parameters; A dynamic characteristic verification module, used to perform dynamic characteristic verification on the ship shafting model based on the strength stress of the ship shafting, and determine vibration performance parameters and anti-shock performance parameters; The optimal air-to-diameter ratio determination module is used to determine the optimal air-to-diameter ratio by using a multi-objective optimization method based on the strength performance parameters, vibration performance parameters and impact resistance performance parameters.

9. An electronic device, characterized in that: including memory and processor; The memory stores a computer-readable program executable by the processor; When the processor executes the computer-readable program, the steps in the method for selecting the space-to-diameter ratio of a ship shaft system as described in any one of claims 1 to 7 are implemented.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores one or more programs, and the one or more programs can be executed by one or more processors to implement the steps in the method for selecting the air-to-diameter ratio of a ship shaft system as described in any one of claims 1-7.

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