Design method and system for ultimate bearing capacity similar model of cylindrical ring rib pressure-resistant shell

Abstract

The invention discloses a design method and system of a cylindrical ring rib pressure-resistant shell ultimate bearing capacity similar model, and relates to the field of cylindrical ring rib pressure-resistant shells. The problem of design of an existing ultimate bearing capacity similar model of the pressure-resistant shell structure is solved. The method comprises the following steps: S1, determining size parameters of a pressure-resistant shell prototype, and establishing a finite element model of the pressure-resistant shell prototype; s2, defining the relation between the scale ratio of the grid width of the cylindrical ring rib pressure-resistant shell and the scale ratio of the radius and the scale ratio of the plate thickness of the cylindrical ring rib pressure-resistant shell; s3, calculating the scale ratio of the shell plate grid width of the cylindrical ring rib pressure-resistant shell; s4, calculating a relationship between parameters such as the scale ratio of the geometric length of the cylindrical ring rib pressure-resistant shell and the number of ring ribs of the scale model; s5, calculating the number of ring ribs of the reduced scale model based on S3 and S4; s6, determining size parameters of the cylindrical ring rib pressure-resistant shell reduced scale model, and establishing a finite element model of the reduced scale model; and S7, respectively analyzing the buckling strength and the ultimate strength of the pressure-resistant shell prototype and the pressure-resistant shell reduced-scale model, verifying the accuracy of the reduced-scale model, and completing the design of the model.

Description

Technical Field

[0001] The invention relates to the technical field of cylindrical ring-ribbed pressure hulls, and in particular to a design method and system for a similar model of the ultimate bearing capacity of a cylindrical ring-ribbed pressure hull. Background Art

[0002] Underwater vehicles are a kind of modern emerging strategic equipment that can be used for underwater reconnaissance, hydrographic survey and marine scientific research. As the main load-bearing structure of underwater vehicles in deep-sea operations, the safety of the pressure hull structure under the action of extreme water pressure is related to whether the entire equipment system can successfully complete the task. The ultimate bearing capacity of the pressure hull determines the maximum depth to which it can dive, affecting its own safety and the degree of execution of strategic tasks. After the pressure hull structure dives into deeper waters, under the action of uniformly distributed water pressure, the pressure hull structure will experience material nonlinearity and geometric nonlinearity.

[0003] In order to evaluate the ultimate bearing capacity of the pressure hull structure, it is often necessary to carry out numerical and experimental research simultaneously to accurately obtain the ultimate diving depth of the pressure hull structure. Considering the high economic cost of conducting the ultimate bearing capacity test of the full-scale pressure hull, the difficulty in ensuring the test loading conditions, and the difficulty in test measurement, in comparison, conducting a scaled model test is a reliable and low-cost option. Therefore, for typical ring-ribbed pressure hull structures, it is necessary to establish a similar model design method with high accuracy, simple design process and wide applicability, so as to carry out similar model tests instead of full-scale model tests, so as to more accurately and effectively predict the ultimate bearing capacity of the prototype.

[0004] Patent document publication number CN118797825A proposes a method for determining the initial design parameters of a submersible light shell based on a sandwich composite structure. The method determines the installation position and geometric parameters of each sandwich composite panel slice according to the pressure shell structure of the submersible, and then constructs the sound insulation thickness relationship and stress thickness relationship between the sound insulation and stress maximum value of each sandwich composite panel slice and the thickness of the skin panel and the thickness of the core material; under the constraints of the sound insulation thickness relationship, the stress thickness relationship and the total thickness relationship, the thickness of the core material and the skin panel can be determined so that each sandwich composite panel slice satisfies the acoustic performance constraints, mechanical performance constraints and thickness constraints at the same time, thereby quickly giving the initial design parameters of the submersible light shell that initially meet the performance requirements, that is, designing for the full-scale submersible shell. The method described in the present invention is a scaled model size design method for realizing the similar ultimate bearing capacity of the pressure shell, and the structural size design problems involved are inconsistent.

[0005] Patent document publication number CN112307659A proposes a method for calculating the ultimate bearing capacity of a double-layer cylindrical pressure hull, and discloses a simulation modeling process for calculating the ultimate bearing capacity of the pressure hull. However, the method described in the present invention is to achieve a similar ultimate bearing capacity, that is, to solve a different technical problem.

[0006] Patent document publication number CN114741927A proposes a method and device for testing the ultimate strength of a stiffened plate under a combined load, that is, applying a concentrated load to the loading block through two mutually perpendicular axial loads to uniformly transfer the biaxial load, and achieving uniform lateral loading pressure by covering with sandbags and applying weights, and combining displacement and deformation sensors to achieve the ultimate strength test of the scaled model of the stiffened plate under the combined action of three-dimensional loads, thereby obtaining the ultimate strength of the prototype under the combined action of three-dimensional loads, providing technical support for the structural design of the stiffened plate. The method described in the present invention is a scaled model design method for a pressure hull structure under an out-of-plane uniformly distributed load, and the target structure and load conditions involved are inconsistent.

[0007] In summary, the ultimate bearing capacity of the pressure hull structure determines the effective diving depth of the underwater vehicle. Therefore, the ultimate bearing capacity of the pressure hull structure should be accurately evaluated when designing the underwater vehicle. In order to be able to carry out scaled model tests to reflect the ultimate bearing characteristics of the large-scale prototype, it is necessary to solve the problem of designing a similar model of the ultimate bearing capacity of the pressure hull structure, and finally realize that the buckling strength and ultimate strength of the scaled model can reflect the buckling strength and ultimate strength of the prototype respectively. Summary of the invention

[0008] The invention aims to solve the problem of similar model design for the ultimate bearing capacity of a pressure hull structure in the prior art.

[0009] To solve the above technical problems, the present invention is achieved through the following technical solutions:

[0010] Solution 1: The present invention proposes a design method for a similar model of the ultimate bearing capacity of a cylindrical ring-ribbed pressure hull, the method comprising the following steps:

[0011] The method comprises the following steps:

[0012] S1. Determine the size parameters of the pressure hull prototype and establish a finite element model of the pressure hull prototype;

[0013] S2. Based on the calculation formula of critical buckling strength of unreinforced pressure hull, define the scale ratio C of the width of cylindrical ring-stiffened pressure hull panel. l Ratio of radius to C R And plate thickness reduction ratio C t relationship;

[0014] S3, determining the main scale ratio of the cylindrical ring-ribbed pressure hull, wherein the main scale ratio includes the radius scale ratio C of the cylindrical ring-ribbed pressure hull. R And plate thickness reduction ratio C t , based on the reduction ratio C of the cylindrical ring-stiffened pressure hull panel width described in S2 l Ratio of radius to C R And plate thickness reduction ratio C t Calculate the reduction ratio C of the shell panel width of the cylindrical ring-stiffened pressure shell based on the relationship between l ;

[0015] S4. Based on the calculation formula for the critical buckling strength of the unreinforced pressure hull described in S2, calculate the reduction ratio C of the geometric length of the cylindrical ring-ribbed pressure hull. L , Radius reduction ratio C R , Plate thickness reduction ratio C t 、Number of ring ribs in the original model p and the number of ring ribs in the scaled model N S relationship;

[0016] S5. Determine the reduction ratio C of the geometric length of the cylindrical ring-stiffened pressure shell L , based on the reduction ratio C of the cylindrical ring-stiffened pressure shell panel width determined in S3 and S4 l Ratio of radius to C R And plate thickness reduction ratio C t The reduction ratio C of the geometric length of the cylindrical ring-stiffened pressure shell L , Radius reduction ratio C R , Plate thickness reduction ratio C t 、Number of ring ribs in the original model p and the number of ring ribs in the scaled model N S Calculate the number of ring ribs N of the scaled model S ;

[0017] S6. Scale ratio C of the geometric length of the cylindrical ring-stiffened pressure hull based on S3 and S5 L , Radius reduction ratio C R , Plate thickness reduction ratio C t , Number of ring ribs in scaled model N S , determine the size parameters of the scaled model of the cylindrical ring-ribbed pressure shell, and establish a finite element model of the scaled model;

[0018] S7. Analyze the buckling strength and ultimate strength of the pressure hull prototype described in S1 and the scaled model of the pressure hull in S6 respectively, verify the accuracy of the scaled model, and complete the design of a similar model for the ultimate bearing capacity of the cylindrical ring-ribbed pressure hull.

[0019] Further, a preferred embodiment is provided, wherein the pressure hull prototype size parameters in S1 include the pressure hull wall thickness t p、Ring Rib N p , Pressure hull length L p 、Radius of pressure hull R p 、Pressure shell panel width l p .

[0020] Further, a preferred embodiment is provided, wherein the critical buckling strength q of the unreinforced pressure hull described in S2 is cr The calculation formula is:

[0021]

[0022] Wherein, E is the elastic modulus, R is the radius of the pressure hull, L is the geometric length of the unreinforced pressure hull, the width of the cylindrical ring-ribbed pressure hull panel is l, and t is the wall thickness of the pressure hull.

[0023] Further, a preferred embodiment is provided, in which the reduction ratio C of the geometric length of the pressure hull is defined in S2 l Ratio of radius to C R And plate thickness reduction ratio C t The relationship is: C l =C t 5 / 2 C R -3 / 2 .

[0025] Further, a preferred embodiment is provided, in S3 based on the pressure hull radius scale ratio C R , Plate thickness reduction ratio C t , Panel width reduction ratio C l , determining the size parameters of the cylindrical ring-ribbed pressure shell scale model also includes determining the radius R of the pressure shell scale model s , the thickness of the scaled model of the pressure hull t s , the panel width l of the scaled model of the pressure hull s steps.

[0026] Further, a preferred embodiment is provided, based on the calculation formula of the critical buckling strength of the unreinforced pressure hull described in S4, the reduction ratio C of the geometric length of the cylindrical ring-ribbed pressure hull is calculated. L , Radius reduction ratio C R , Plate thickness reduction ratio C t 、Number of ring ribs in the original model p and the number of ring ribs in the scaled model N S The relationship is:

[0027] N s =C L C R 1.5 C t -2.5 (N p +1)-1.

[0028] Further, a preferred embodiment is provided, in S5 based on the pressure hull radius scale ratio C R , Plate thickness reduction ratio C t , geometric length scale ratio C L , the number of ring ribs in the original model N p , determining the size parameters of the cylindrical ring-ribbed pressure shell scale model also includes determining the radius R of the pressure shell scale model s , the thickness of the scaled model of the pressure hull t s , the geometric length L of the scaled model of the pressure hull s , Number of ring ribs in scaled model N S steps.

[0029] Furthermore, a preferred embodiment is provided, wherein S5 also includes a step of determining the size parameters of the ring-ribbed pressure hull according to each scale ratio.

[0030] Further, a preferred embodiment is provided, wherein the reduction ratio C of the pressure hull wall thickness in S4 is t Equal to the reduction ratio C of the pressure hull radius R .

[0031] Solution 2: A design system for a similar model of the ultimate bearing capacity of a cylindrical ring-stiffened pressure hull, the system comprising:

[0032] The pressure hull prototype building module is used to determine the size parameters of the pressure hull prototype and build a finite element model of the pressure hull prototype;

[0033] The parameter determination module is used to define the reduction ratio C of the width of the cylindrical ring-stiffened pressure shell panel based on the calculation formula of the critical buckling strength of the unreinforced pressure shell. l Ratio of radius to C R And plate thickness reduction ratio C t relationship;

[0034] The parameter calculation module is used to determine the main scale ratio of the cylindrical ring-ribbed pressure hull, wherein the main scale ratio includes the radius scale ratio C of the cylindrical ring-ribbed pressure hull. R And plate thickness reduction ratio C t , based on the parameter determination module, the scale ratio C of the cylindrical ring-stiffened pressure hull panel width l Ratio of radius to C R And plate thickness reduction ratio C t Calculate the reduction ratio C of the shell panel width of the cylindrical ring-stiffened pressure shell based on the relationship between l ;

[0035] The module for calculating the geometric length parameters of the cylindrical ring-stiffened pressure hull is used to calculate the reduction ratio C of the geometric length of the cylindrical ring-stiffened pressure hull based on the calculation formula for the critical buckling strength of the unreinforced pressure hull described in the parameter determination module. L , Radius reduction ratio C R , Plate thickness reduction ratio C t 、Number of ring ribs in the original model p and the number of ring ribs in the scaled model N S relationship;

[0036] Scaled model ring rib number calculation module, used to determine the scale ratio C of the geometric length of the cylindrical ring rib pressure shell L , based on the scale ratio C of the cylindrical ring-stiffened pressure shell panel width determined in the parameter calculation module and the cylindrical ring-stiffened pressure shell geometric length parameter calculation module l Ratio of radius to C R And plate thickness reduction ratio C t The reduction ratio C of the geometric length of the cylindrical ring-stiffened pressure shell L , Radius reduction ratio C R , Plate thickness reduction ratio C t 、Number of ring ribs in the original model p and the number of ring ribs in the scaled model N S Calculate the number of ring ribs N of the scaled model S ;

[0037] The scaled model finite element model building module is used for the scaled ratio C of the geometric length of the cylindrical ring rib pressure shell based on the parameter calculation module and the scaled model ring rib number calculation module. L , Radius reduction ratio C R , Plate thickness reduction ratio C t , Number of ring ribs in scaled model N S , determine the size parameters of the scaled model of the cylindrical ring-ribbed pressure shell, and establish a finite element model of the scaled model;

[0038] The design module is used to analyze the buckling strength and ultimate strength of the pressure hull prototype described in the pressure hull prototype establishment module and the pressure hull scaled model in the finite element model establishment module of the scaled model, verify the accuracy of the scaled model, and complete the design of a similar model for the ultimate bearing capacity of the cylindrical ring-ribbed pressure hull.

[0039] The present invention is beneficial in that:

[0040] The design method and system of the similar model of the ultimate bearing capacity of a cylindrical ring-ribbed pressure hull of the present invention have a similarity error of no more than 5% between the buckling strength of the scaled model of the pressure hull and the buckling strength of the prototype, and a similarity error of no more than 7% between the ultimate strength of the scaled model of the pressure hull and the ultimate strength of the prototype. The application range is wide, and the aspect ratio L / R is between 2 and 10. The scaled design process is simple, and the size of the scaled model can be obtained according to the corresponding scale ratio and the design formula.

[0041] The design method and system of a similar model for the ultimate bearing capacity of a cylindrical ring-ribbed pressure hull of the present invention have high accuracy, a simple design process and a wide range of applications.

[0042] The invention is also applicable to the field of design of similar models of ultimate bearing capacity. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 It is a schematic diagram of the pressure hull in the design method of the similarity model of the ultimate bearing capacity of the cylindrical ring-ribbed pressure hull described in the second implementation mode.

[0044] Figure 2 This is a schematic diagram of the dimensional parameters of the prototype size of the pressure hull described in the eleventh embodiment.

[0045] Figure 3 This is a schematic diagram of the size parameters of the prototype of the pressure hull with ring ribs described in the eleventh embodiment.

[0046] Figure 4 This is a displacement cloud diagram of the pressure hull in the limit state described in the eleventh embodiment.

[0047] Figure 5 This is a schematic diagram of the size parameters of the pressure hull deformation scale model described in the eleventh embodiment.

[0048] Figure 6 This is a schematic diagram of the size parameters of the scaled model of the pressure hull with ring ribs according to the eleventh embodiment.

[0049] Figure 7 This is a displacement cloud diagram of the scaled-down model of the pressure hull in the limit state described in the eleventh embodiment.

[0050] Figure 2 Where 1 is the thickness of the pressure shell t p , 2 is the ring rib, 3 is the length of the pressure shell L p , 4 is the radius R of the pressure shell p . DETAILED DESCRIPTION

[0051] In order to make the purpose, technical solutions and advantages of the implementation methods of the present application clearer, the technical solutions in the implementation methods of the present application will be clearly and completely described below in conjunction with the drawings in the implementation methods of the present application. Obviously, the described implementation methods are only part of the implementation methods of the present application, not all of the implementation methods.

[0052] Embodiment 1: This embodiment provides a design method for a similar model of the ultimate bearing capacity of a cylindrical ring-ribbed pressure hull, the method comprising the following steps:

[0053] S1. Determine the size parameters of the pressure hull prototype and establish a finite element model of the pressure hull prototype;

[0054] S2. Based on the calculation formula of critical buckling strength of unreinforced pressure hull, define the scale ratio C of the width of cylindrical ring-stiffened pressure hull panel. l Ratio of radius to C R And plate thickness reduction ratio C t relationship;

[0055] S3, determining the main scale ratio of the cylindrical ring-ribbed pressure hull, wherein the main scale ratio includes the radius scale ratio C of the cylindrical ring-ribbed pressure hull. R And plate thickness reduction ratio C t , based on the reduction ratio C of the cylindrical ring-stiffened pressure hull panel width described in S2 l Ratio of radius to C R And plate thickness reduction ratio C t Calculate the reduction ratio C of the shell panel width of the cylindrical ring-stiffened pressure shell based on the relationship between l ;

[0056] S4. Based on the calculation formula for the critical buckling strength of the unreinforced pressure hull described in S2, calculate the reduction ratio C of the geometric length of the cylindrical ring-ribbed pressure hull. L , Radius reduction ratio C R , Plate thickness reduction ratio C t 、Number of ring ribs in the original model p and the number of ring ribs in the scaled model N S relationship;

[0057] S5. Determine the reduction ratio C of the geometric length of the cylindrical ring-stiffened pressure shell L , based on the reduction ratio C of the cylindrical ring-stiffened pressure shell panel width determined in S3 and S4 l Ratio of radius to C R And plate thickness reduction ratio C t The reduction ratio C of the geometric length of the cylindrical ring-stiffened pressure shell L , Radius reduction ratio C R , Plate thickness reduction ratio C t 、Number of ring ribs in the original model p and the number of ring ribs in the scaled model NS Calculate the number of ring ribs N of the scaled model S ;

[0058] S6. Scale ratio C of the geometric length of the cylindrical ring-stiffened pressure hull based on S3 and S5 L , Radius reduction ratio C R , Plate thickness reduction ratio C t , Number of ring ribs in scaled model N S , determine the size parameters of the scaled model of the cylindrical ring-ribbed pressure shell, and establish a finite element model of the scaled model;

[0059] S7. Analyze the buckling strength and ultimate strength of the pressure hull prototype described in S1 and the scaled model of the pressure hull in S6 respectively, verify the accuracy of the scaled model, and complete the design of a similar model for the ultimate bearing capacity of the cylindrical ring-ribbed pressure hull.

[0060] Embodiment 2: This embodiment further defines the design method of the similarity model of the ultimate bearing capacity of the cylindrical ring-ribbed pressure hull described in Embodiment 1. The pressure hull prototype size parameters in S1 include the pressure hull wall thickness t p 1. Ring rib N p 2. Pressure hull length L p 3. Pressure hull radius R p 4. Pressure shell panel width l p .

[0061] Implementation method 3: This implementation method further defines the design method of the similarity model of the ultimate bearing capacity of the cylindrical ring-ribbed pressure hull described in Implementation method 1. The critical buckling strength q of the unreinforced pressure hull described in S2 is cr The calculation formula is:

[0062]

[0063] Wherein, E is the elastic modulus, R is the radius of the pressure hull, L is the geometric length of the unreinforced pressure hull, the width of the cylindrical ring-ribbed pressure hull panel is l, and t is the wall thickness of the pressure hull.

[0064] Embodiment 4: This embodiment further defines the design method of the similarity model of the ultimate bearing capacity of the cylindrical ring-ribbed pressure hull described in Embodiment 1. The scale ratio C of the geometric length of the pressure hull defined in S2 is l Ratio of radius to C R And plate thickness reduction ratio C t The relationship is: C l =C t 5 / 2 C R -3 / 2 .

[0066] Embodiment 5: This embodiment further defines the design method of the similarity model of the ultimate bearing capacity of the cylindrical ring-ribbed pressure hull described in Embodiment 1. In S3, based on the pressure hull radius scale ratio C R , Plate thickness reduction ratio C t , Panel width reduction ratio C l , determining the size parameters of the cylindrical ring-ribbed pressure shell scale model also includes determining the radius R of the pressure shell scale model s , the thickness of the scaled model of the pressure hull t s , the panel width l of the scaled model of the pressure hull s steps.

[0067] Embodiment 6: This embodiment further defines the design method of the similarity model of the ultimate bearing capacity of the cylindrical ring-stiffened pressure hull described in Embodiment 1. Based on the calculation formula for the critical buckling strength of the unreinforced pressure hull described in S4, the reduction ratio C of the geometric length of the cylindrical ring-stiffened pressure hull is calculated. L , Radius reduction ratio C R , Plate thickness reduction ratio C t 、Number of ring ribs in the original model p and the number of ring ribs in the scaled model N S The relationship is:

[0068] N s =C L C R 1.5 C t -2.5 (N p +1)-1.

[0069] Embodiment 7: This embodiment further defines the design method of the similarity model of the ultimate bearing capacity of the cylindrical ring-ribbed pressure hull described in Embodiment 6. In S5, based on the pressure hull radius scale ratio C R , Plate thickness reduction ratio C t , geometric length scale ratio C L , the number of ring ribs in the original model N p , determining the size parameters of the cylindrical ring-ribbed pressure shell scale model also includes determining the radius R of the pressure shell scale model s , the thickness of the scaled model of the pressure hull t s , the geometric length L of the scaled model of the pressure hull s , Number of ring ribs in scaled model N S steps.

[0070] Embodiment 8: This embodiment further limits the design method of the similarity model of the ultimate bearing capacity of the cylindrical ring-stiffened pressure hull described in Embodiment 6, and S5 also includes the step of determining the size parameters of the ring-stiffened pressure hull according to each scale ratio.

[0071] Embodiment 9: This embodiment further defines the design method of the similarity model of the ultimate bearing capacity of the cylindrical ring-ribbed pressure hull described in Embodiment 1. The reduction ratio C of the pressure hull wall thickness described in S4 is t Equal to the reduction ratio C of the pressure hull radius R .

[0072] Embodiment 10: This embodiment proposes a design system for a similarity model of the ultimate bearing capacity of a cylindrical ring-stiffened pressure hull, the system comprising:

[0073] The pressure hull prototype building module is used to determine the size parameters of the pressure hull prototype and build a finite element model of the pressure hull prototype;

[0074] The parameter determination module is used to define the reduction ratio C of the width of the cylindrical ring-stiffened pressure shell panel based on the calculation formula of the critical buckling strength of the unreinforced pressure shell. l Ratio of radius to C R And plate thickness reduction ratio C t relationship;

[0075] The parameter calculation module is used to determine the main scale ratio of the cylindrical ring-ribbed pressure hull, wherein the main scale ratio includes the radius scale ratio C of the cylindrical ring-ribbed pressure hull. R And plate thickness reduction ratio C t , based on the parameter determination module, the scale ratio C of the cylindrical ring-stiffened pressure hull panel width l Ratio of radius to C R And plate thickness reduction ratio C t Calculate the reduction ratio C of the shell panel width of the cylindrical ring-stiffened pressure shell based on the relationship between l ;

[0076] The module for calculating the geometric length parameters of the cylindrical ring-stiffened pressure hull is used to calculate the reduction ratio C of the geometric length of the cylindrical ring-stiffened pressure hull based on the calculation formula for the critical buckling strength of the unreinforced pressure hull described in the parameter determination module. L , Radius reduction ratio C R , Plate thickness reduction ratio C t 、Number of ring ribs in the original model p and the number of ring ribs in the scaled model N S relationship;

[0077] Scaled model ring rib number calculation module, used to determine the scale ratio C of the geometric length of the cylindrical ring rib pressure shell L , based on the scale ratio C of the cylindrical ring-stiffened pressure shell panel width determined in the parameter calculation module and the cylindrical ring-stiffened pressure shell geometric length parameter calculation module l Ratio of radius to C R And plate thickness reduction ratio C t The reduction ratio C of the geometric length of the cylindrical ring-stiffened pressure shellL , Radius reduction ratio C R , Plate thickness reduction ratio C t 、Number of ring ribs in the original model p and the number of ring ribs in the scaled model N S Calculate the number of ring ribs N of the scaled model S ;

[0078] The scaled model finite element model building module is used for the scaled ratio C of the geometric length of the cylindrical ring rib pressure shell based on the parameter calculation module and the scaled model ring rib number calculation module. L , Radius reduction ratio C R , Plate thickness reduction ratio C t , Number of ring ribs in scaled model N S , determine the size parameters of the scaled model of the cylindrical ring-ribbed pressure shell, and establish a finite element model of the scaled model;

[0079] The design module is used to analyze the buckling strength and ultimate strength of the pressure hull prototype described in the pressure hull prototype establishment module and the pressure hull scaled model in the finite element model establishment module of the scaled model, verify the accuracy of the scaled model, and complete the design of a similar model for the ultimate bearing capacity of the cylindrical ring-ribbed pressure hull.

[0080] Implementation eleven: This implementation provides an example, which is used to explain the above implementations one to ten. The specific example is as follows:

[0081] See also Figures 1 to 7 To illustrate this embodiment, this embodiment is based on a cylindrical ring-ribbed pressure hull, which is composed of a pressure hull shell and ring ribs. Generally, the ring ribs can be arranged on the outside or inside of the pressure hull. Since the supporting effect of the ring ribs on the pressure hull is relatively weak, this embodiment is only described by taking the case where the ring ribs are on the inside of the pressure hull as an example.

[0082] The present embodiment provides a design method for a similar model of the ultimate bearing capacity of a cylindrical ring-stiffened pressure hull, comprising:

[0083] Step 1: Determine the dimensional parameters of the pressure hull prototype, including the pressure hull wall thickness t indicated by 1 in the figure. p ; The ring ribs indicated by 2 in the figure, the number of ring ribs, the number of ring ribs N p , height of ring rib web h w and the thickness of the web of the ring rib t w ; The pressure hull length L indicated by 3 in the figure p ; The radius R of the pressure shell indicated by 4 in the figure p ;

[0084] Step 2: In order to solve the elastic buckling problem of cylindrical thin shell under the action of out-of-plane uniform load in the prior art, the critical buckling strength q of the unreinforced pressure shell is obtained through research.cr Calculate the formula, where:

[0085] Step 3

[0086] Step 4: Determine the scale ratio of the main dimensions of the unreinforced pressure hull, including the scale ratio C of the pressure hull radius. R , the reduction ratio of the pressure hull length C L , the reduction ratio of wall thickness is C t ;

[0087] Step 5: Considering that the prototype without stiffeners and the scaled model of the pressure hull have similar critical buckling strength, the scale ratio C of the geometric length of the pressure hull can be derived when the material properties are consistent. L Ratio of radius to C R And plate thickness reduction ratio C t Relationship, where:

[0088] Step 6. C L =C t 5 / 2 C R -3 / 2 ;

[0089] Step 7: When all the scale ratios related to the geometric scale are designed to be the same value, and the scale ratios related to the thickness are designed to be different from the geometric scale ratio, there is a difference in the critical buckling strength between the scaled model and the prototype, and similar buckling strength cannot be achieved. Therefore, in step 4, only the scale ratio C of the pressure hull radius is determined. R The reduction ratio of the pressure shell plate thickness is C t , the reduction ratio C of the pressure hull geometric length is further determined by step 6 L ;

[0090] Step 8. From step 6, when the reduction ratio of the plate thickness is consistent with the reduction ratio of the radius, the reduction ratio of the geometric length is the same as the reduction ratio of the radius, that is, a full similarity model. When the reduction ratio of the plate thickness is different from the reduction ratio of the radius, there is a difference between the reduction ratio of the geometric length and the reduction ratio of the radius, which constitutes the so-called distortion model;

[0091] Step 9: Determine the size parameters of the scaled model according to each scale ratio, where:

[0092] Step 10: Pressure hull radius R s =R p C R ;

[0093] Step 11: Pressure hull thickness t s =t p C t ;

[0094] Step 12: Pressure hull length Ls =L p C L ;

[0095] Step 13: Continue to consider the case of a ring-ribbed pressure hull. The length of the ring-ribbed pressure hull can be determined by the number of ring ribs N and the distance l between adjacent ring ribs. At this time, the critical buckling strength q of the pressure hull without ring ribs is still used. cr Based on the calculation formula, considering its role in the plate grid between two adjacent ring ribs of the pressure hull with ring ribs, the number of ring ribs N of the pressure hull of the scaled model can be obtained from the similar buckling strength of the prototype and the scaled model pressure hull. s The expression of the scale model pressure shell ring rib number N s :

[0096] Step 14: Number of ring ribs N s =C L C R 1.5 C t -2.5 (N p +1)-1

[0097] Step 15: When C L =C R In order to satisfy the requirement that the number of ring ribs is an integer, Ct / CL needs to be a special ratio such as 1 / 4, 1 / 9, 1 / 16. t =C R The number of ring ribs in the scaled model can easily meet the integer requirement, and considering that the diameter-to-thickness ratio is one of the most important factors affecting the buckling strength of the pressure hull, the present invention requires C t =C R .

[0098] Step 16: The number of ring ribs in the scaled model can be determined by step 14, and the size parameters of the pressure hull with ring ribs are further determined by each scale ratio, wherein:

[0099] Step 17: Pressure hull radius R s =R p C R ;

[0100] Step 18: Pressure hull thickness t s-p =t p-p C t And C t =C R ;

[0101] Step 19: Ring rib thickness t s-w =t p-w C t ;

[0102] Step 20: Ring rib web height hs =h p C L ;

[0103] Step 21: Plate grid width or ring rib size

[0104] Embodiment 1, step 1: numerical verification of scaled design of full similarity model and distortion model of unreinforced pressure hull: establish a prototype finite element model of the pressure hull with a given prototype size, determine the dimensional parameters of the scaled model of the pressure hull by steps 3-6 and establish a finite element model of the scaled model, analyze the buckling strength and ultimate strength of the prototype and scaled model respectively, and verify the accuracy of the design method.

[0105] Step 2, Example 1:

[0106] Step 3. Prototype size: length L p 10000mm, radius R p 1250mm, wall thickness t p 25mm;

[0107] Step 4: Determine the scale ratio of the full similarity model: length scale ratio C L 1 / 5, radius reduction ratio C R 1 / 5, pressure shell thickness reduction ratio C t is 1 / 5;

[0108] Step 5: After determining the scale ratio of the full similarity model, calculate the scaled model size: length L s 2000mm, radius R s 250mm, wall thickness t s-p 5mm;

[0109] Step 6: According to the Abaqus numerical calculation results, the buckling q of the prototype p is 1.9498MPa, the limit q p-max The buckling q of the fully similar scale model is 1.9839MPa. s is 1.9539MPa, the limit q s-max 1.9572MPa;

[0110] Step 2, Example 2:

[0111] Step 7: Determine the scale ratio of the distortion model: radius scale ratio C R 1 / 8, pressure shell thickness reduction ratio C t is 1 / 10;

[0112] Step 8: After determining the scale ratio of the distortion model, determine the length scale ratio C of the model by step 6. Lis 0.0716, thus calculating the length L of the distorted scale model s 716mm, radius R s 156.25mm, wall thickness t s-p 2.5mm;

[0113] Step 9: According to the Abaqus numerical calculation results, the buckling q of the prototype p is 1.9498MPa, the limit q p-max is 1.9839MPa, and the buckling q of the scaled model s is 2.0131MPa, the limit q s-max 2.0327MPa;

[0114] Step 10. Numerical results show that the buckling load error between the unreinforced pressure shell prototype and the fully similar scaled model is 1.75%, and the error of the ultimate load is 0.17%. The buckling load error between the prototype and the distorted scaled model is 3.25%, and the error of the ultimate load is 2.46%. The errors of the buckling load and the ultimate load are small, so the scaled model can more accurately reflect the buckling and ultimate conditions of the prototype.

[0115] Step 11. Numerical verification of scaled design of full similarity model and distortion model of reinforced pressure hull: Establish a prototype finite element model of the pressure hull with a given prototype size. Determine the size parameters of the scaled model of the pressure hull by steps 13-21 and establish a finite element model of the scaled model. Analyze the buckling strength and ultimate strength of the prototype and scaled model respectively to verify the accuracy of the design method.

[0116] Step 12, Example 1,

[0117] Step 13. Prototype size: length L p 12000mm, radius R p 2500mm, wall thickness t p is 25mm, the plate grid width or ring rib size lp is 2000mm, the ring rib thickness t s-p is 25mm, and the ring rib web height hp is 100mm;

[0118] Step 14: Determine the scale ratio of the full similarity model: length scale ratio C L 1 / 5, radius reduction ratio C R 1 / 5, pressure shell thickness reduction ratio C t is 1 / 5;

[0119] Step 15: After determining the scale ratio of the full similarity model, calculate the scaled model size: length L s 2400mm, radius R s 500mm, wall thickness t s-p5mm, plate grid width or ring rib size l s 400mm, ring rib thickness t s-w 5mm, the height of the ring rib web h s 20mm;

[0120] Step 16: According to the Abaqus numerical calculation results, the buckling q of the prototype p is 1.2675MPa, the limit q p-max The buckling q of the scaled model is 1.3463MPa. s is 1.2759MPa, the limit q s-max 1.3469MPa;

[0121] Step 17: Determine the scale ratio of the distortion model: length scale ratio C L 1 / 5, radius reduction ratio C R The pressure shell thickness reduction ratio is 3 / 10. t 3 / 10;

[0122] Step 18: After determining the scale ratio of the distortion model, determine the scale model size by steps 13-21: length L s 2400mm, radius R s 600mm, wall thickness t s-p 7.5mm, plate grid width or ring rib size l s 600mm, ring rib thickness t s-w 7.5mm, height of the ring rib web h s 20mm;

[0123] Step 19: According to the Abaqus numerical calculation results, the buckling q of the prototype p is 1.2675MPa, the limit q p-max is 1.3463MPa, and the buckling q of the scaled model s is 1.2840MPa, the limit q s-max 1.3074MPa;

[0124] Step 20. Numerical results show that the buckling load error between the reinforced pressure shell prototype and the full similarity scale model is 0.66%, and the error of the ultimate load is 0.04%. The buckling load error between the prototype and the distorted scale model is 1.3%, and the error of the ultimate load is 2.89%. The errors of the buckling load and the ultimate load are small, so the scale model can accurately reflect the buckling and ultimate conditions of the prototype.

[0125] Embodiment 2: When conducting a pressure hull model test, there are problems such as the pressure hull being too large, there being no matching test site, or the model being too expensive. Therefore, it is necessary to scale the pressure hull model, and the scaled model must be similar to the original model in terms of buckling load, ultimate bearing capacity, failure mode, etc. According to the distortion model scaling design principle of the present invention, the original model is scaled to meet the requirements of buckling load, ultimate bearing capacity, failure mode, etc., and the test site requirements.

[0126] For example, there is a pressure shell model with a length L p 12000mm, radius R p 2500mm, wall thickness t p is 25mm, the plate grid width or ring rib size lp is 2000mm, the ring rib thickness t s-p The length of the rib web is 25 mm, and the height of the rib web hp is 100 mm. In order to reduce the test cost and meet the site requirements, the model needs to be distorted, and the scale design is performed according to the distortion model scale design principle of the present invention. Distortion model scale ratio: length scale ratio C L 1 / 5, radius reduction ratio C R The pressure shell thickness reduction ratio is 3 / 10. t 3 / 10. Calculate the length L of the scaled model s 2400mm, radius R s 600mm, wall thickness t s-p 7.5mm, plate grid width or ring rib size l s 600mm, ring rib thickness t s-w 7.5mm, height of the ring rib web h s is 20mm.

[0127] Those skilled in the art will appreciate that the above are only preferred embodiments of the present invention, and the various embodiments of the present disclosure and / or the features described in the claims may be combined or combined in various ways, even if such combinations or combinations are not explicitly described in the present disclosure. It is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art may still modify the technical solutions described in the aforementioned embodiments, or perform equivalent substitutions on some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention shall be included in the protection scope of the present invention.

[0128] Although preferred embodiments of the present invention have been described, additional changes and modifications may be made to these embodiments by those skilled in the art once the basic inventive concepts are known. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention. Obviously, those skilled in the art may make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A design method for a similarity model of the ultimate bearing capacity of a cylindrical ring-stiffened pressure hull, characterized in that: The method comprises the following steps: S1. Determine the size parameters of the pressure hull prototype and establish a finite element model of the pressure hull prototype; S2. Based on the calculation formula of critical buckling strength of unreinforced pressure hull, define the scale ratio C of the width of cylindrical ring-stiffened pressure hull panel. l Ratio of radius to C R And plate thickness reduction ratio C t relationship; S3, determining the main scale ratio of the cylindrical ring-ribbed pressure hull, wherein the main scale ratio includes the radius scale ratio C of the cylindrical ring-ribbed pressure hull. R And plate thickness reduction ratio C t , based on the reduction ratio C of the cylindrical ring-stiffened pressure hull panel width described in S2 l Ratio of radius to C R And plate thickness reduction ratio C t Calculate the reduction ratio C of the shell panel width of the cylindrical ring-stiffened pressure shell based on the relationship between l ; S4. Based on the calculation formula for the critical buckling strength of the unreinforced pressure hull described in S2, calculate the reduction ratio C of the geometric length of the cylindrical ring-ribbed pressure hull. L , Radius reduction ratio C R , Plate thickness reduction ratio C t 、Number of ring ribs in the original model p and the number of ring ribs in the scaled model N S relationship; S5. Determine the reduction ratio C of the geometric length of the cylindrical ring-stiffened pressure shell L , based on the reduction ratio C of the cylindrical ring-stiffened pressure shell panel width determined in S3 and S4 l Ratio of radius to C R And plate thickness reduction ratio C t The reduction ratio C of the geometric length of the cylindrical ring-stiffened pressure shell L , Radius reduction ratio C R , Plate thickness reduction ratio C t 、Number of ring ribs in the original model p and the number of ring ribs in the scaled model N S Calculate the number of ring ribs N of the scaled model S ; S6. Scale ratio C of the geometric length of the cylindrical ring-stiffened pressure hull based on S3 and S5 L , Radius reduction ratio C R , Plate thickness reduction ratio C t , Number of ring ribs in scaled model N S , determine the size parameters of the scaled model of the cylindrical ring-ribbed pressure shell, and establish a finite element model of the scaled model; S7. Analyze the buckling strength and ultimate strength of the pressure hull prototype described in S1 and the scaled model of the pressure hull in S6 respectively, verify the accuracy of the scaled model, and complete the design of a similar model for the ultimate bearing capacity of the cylindrical ring-ribbed pressure hull.

2. The design method of the similarity model of the ultimate bearing capacity of the cylindrical ring-stiffened pressure hull according to claim 1 is characterized in that: The pressure hull prototype size parameters described in S1 include the pressure hull wall thickness t p (1) Ring rib N p (2) Pressure hull length L p (3) Pressure hull radius R p (4) Pressure shell panel width l p .

3. The design method of the similarity model of the ultimate bearing capacity of the cylindrical ring-stiffened pressure hull according to claim 1 is characterized in that: The critical buckling strength q of the unreinforced pressure shell described in S2 cr The calculation formula is: Wherein, E is the elastic modulus, R is the radius of the pressure hull, L is the geometric length of the unreinforced pressure hull, the width of the cylindrical ring-ribbed pressure hull panel is l, and t is the wall thickness of the pressure hull.

4. The design method of the similarity model of the ultimate bearing capacity of a cylindrical ring-stiffened pressure hull according to claim 1 is characterized in that: The reduction ratio C of the geometric length of the pressure hull is defined in S2 l Ratio of radius to C R And plate thickness reduction ratio C t The relationship is: C l =C t 5 / 2 C R -3 / 2 。 5. The design method of the similarity model of the ultimate bearing capacity of a cylindrical ring-stiffened pressure hull according to claim 1 is characterized in that: S3 based on the pressure shell radius scale ratio C R , Plate thickness reduction ratio C t , Panel width reduction ratio C l , determining the size parameters of the cylindrical ring-ribbed pressure shell scale model also includes determining the radius R of the pressure shell scale model s , the thickness of the scaled model of the pressure hull t s , the panel width l of the scaled model of the pressure hull s steps.

6. The design method of the similarity model of the ultimate bearing capacity of a cylindrical ring-stiffened pressure hull according to claim 1 is characterized in that: Based on the calculation formula for the critical buckling strength of the unreinforced pressure hull described in S4, the reduction ratio C of the geometric length of the cylindrical ring-stiffened pressure hull is calculated. L , Radius reduction ratio C R , Plate thickness reduction ratio C t 、Number of ring ribs in the original model p and the number of ring ribs in the scaled model N S The relationship is: N s =C L C R 1.5 C t -2.5 (N p +1)-1。 7. The design method of the similarity model of the ultimate bearing capacity of a cylindrical ring-stiffened pressure hull according to claim 1 is characterized in that: S5 based on the pressure hull radius scale ratio C R , Plate thickness reduction ratio C t , geometric length scale ratio C L , the number of ring ribs in the original model N p , determining the size parameters of the cylindrical ring-ribbed pressure shell scale model also includes determining the radius R of the pressure shell scale model s , the thickness of the scaled model of the pressure hull t s , the geometric length L of the scaled model of the pressure hull s , Number of ring ribs in scaled model N S steps.

8. The design method of the similarity model of the ultimate bearing capacity of a cylindrical ring-stiffened pressure hull according to claim 7 is characterized in that: S5 also includes a step of determining the size parameters of the ring-ribbed pressure hull according to each scale ratio.

9. The design method of the similarity model of the ultimate bearing capacity of a cylindrical ring-stiffened pressure hull according to claim 1 is characterized in that: The reduction ratio C of the pressure hull wall thickness described in S4 t Equal to the reduction ratio C of the pressure hull radius R .

10. A design system for a similarity model of the ultimate bearing capacity of a cylindrical ring-stiffened pressure hull, characterized in that: The system comprises: The pressure hull prototype building module is used to determine the size parameters of the pressure hull prototype and build a finite element model of the pressure hull prototype; The parameter determination module is used to define the reduction ratio C of the width of the cylindrical ring-stiffened pressure shell panel based on the calculation formula of the critical buckling strength of the unreinforced pressure shell. l Ratio of radius to C R And plate thickness reduction ratio C t relationship; The parameter calculation module is used to determine the main scale ratio of the cylindrical ring-ribbed pressure hull, wherein the main scale ratio includes the radius scale ratio C of the cylindrical ring-ribbed pressure hull. R And plate thickness reduction ratio C t , based on the parameter determination module, the scale ratio C of the cylindrical ring-stiffened pressure hull panel width l Ratio of radius to C R And plate thickness reduction ratio C t Calculate the reduction ratio C of the shell panel width of the cylindrical ring-stiffened pressure shell based on the relationship between l ; The module for calculating the geometric length parameters of the cylindrical ring-stiffened pressure hull is used to calculate the reduction ratio C of the geometric length of the cylindrical ring-stiffened pressure hull based on the calculation formula for the critical buckling strength of the unreinforced pressure hull described in the parameter determination module. L , Radius reduction ratio C R , Plate thickness reduction ratio C t 、Number of ring ribs in the original model p and the number of ring ribs in the scaled model N S relationship; Scaled model ring rib number calculation module, used to determine the scale ratio C of the geometric length of the cylindrical ring rib pressure shell L , based on the scale ratio C of the cylindrical ring-stiffened pressure shell panel width determined in the parameter calculation module and the cylindrical ring-stiffened pressure shell geometric length parameter calculation module l Ratio of radius to C R And plate thickness reduction ratio C t The reduction ratio C of the geometric length of the cylindrical ring-stiffened pressure shell L , Radius reduction ratio C R , Plate thickness reduction ratio C t 、Number of ring ribs in the original model p and the number of ring ribs in the scaled model N S Calculate the number of ring ribs N of the scaled model S ; The scaled model finite element model building module is used for the scaled ratio C of the geometric length of the cylindrical ring rib pressure shell based on the parameter calculation module and the scaled model ring rib number calculation module. L , Radius reduction ratio C R , Plate thickness reduction ratio C t , Number of ring ribs in scaled model N S , determine the size parameters of the scaled model of the cylindrical ring-ribbed pressure shell, and establish a finite element model of the scaled model; The design module is used to analyze the buckling strength and ultimate strength of the pressure hull prototype described in the pressure hull prototype establishment module and the pressure hull scaled model in the finite element model establishment module of the scaled model, verify the accuracy of the scaled model, and complete the design of a similar model for the ultimate bearing capacity of the cylindrical ring-ribbed pressure hull.

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