A Method and System for Structural Verification of Inland Waterway Vessels Based on Structural Parameter Abstraction Model

Abstract

This invention discloses a ship structure verification method and system based on a structural parameter abstract model. First, it establishes a hierarchical parameter model architecture for ships to achieve parameterization and parameter sharing. Second, it encapsulates parameters to express specific structures using custom features, decouples structures and specifications based on XML dynamic configuration, and abstracts the parameter model. This enables full compatibility and combination verification of various inland waterway ship types and specifications while ensuring calculation accuracy, reducing the technical requirements for users and improving the quality and efficiency of design and drawing review.

Description

Technical Field

[0001] This invention relates to the field of ship structure design, and more specifically, to a method and system for verifying the structural strength of inland waterway vessels. Background Technology

[0002] my country boasts abundant river water resources and a dense network of waterways, creating favorable conditions for the development of inland waterway transport. Inland waterway transport relies on inland vessels; by the end of 2020, inland waterway freight volume reached 3.8 billion tons, exceeding railway freight volume during the same period, and its ratio with ocean freight volume reached 13:1.

[0003] Compared to ocean-going vessels, inland waterway vessels have been developing towards multi-purpose capabilities earlier. For example, a passenger-cargo inland waterway vessel may have the functions of carrying passengers, vehicles, and general cargo. Therefore, when designing and inspecting their structures, the regulatory requirements for passenger ships, roll-on / roll-off ships, etc., must be considered simultaneously. As a result, inland waterway vessels are characterized by multiple ship types and multiple regulatory constraints.

[0004] The design of ship hull structures is primarily based on relevant standards and regulations. Past verification methods generally revolved around these standards, involving manual calculations or the creation of Excel spreadsheets. Each ship type required line-by-line calculations against the standard clauses, and once the standards were updated, the entire spreadsheet needed to be rewritten. This placed a heavy workload on designers, impacting verification efficiency and workload. To automate and improve the efficiency of ship design verification, many scholars and institutions have researched design verification software or systems for various types of ships. While these software programs offer detailed and comprehensive structural standard verification, they primarily address the entire standard for a single ship type or structure, proving inadequate for handling generalized hull structures. Optimizing parametric models of ships is an effective way to address this issue. In recent years, many scholars have studied the parametric representation of ships, aiming to improve model compatibility and transfer efficiency. However, overly simplified model representations also imply the loss of some standard data, significantly reducing the comprehensiveness and accuracy of standard verification. Balancing model compatibility with the accuracy of influence analysis calculations is a crucial constraint on the development of inland waterway ship verification technology. Summary of the Invention

[0005] To address the aforementioned issues, this invention establishes a ship structure verification method and system based on an abstract model of structural parameters, ensuring calculation accuracy while achieving compatible modeling of multiple ship types and coupled verification of multiple standards.

[0006] First, establish a hierarchical parameter model architecture for ships to achieve ship parameterization and parameter sharing.

[0007] Preferably, to simplify the modeling process and ensure accuracy, while considering the large amount of data in inland waterway vessel cross-sections, the parametric model architecture of this invention is designed as a hierarchical, multi-level tree-like data structure of the entire ship - cross-section - plate frame - component - node. The node layer only expresses the Y and Z coordinate information in the cross-section coordinate system, the cross-section expresses the X coordinate information through rib parameters, and the in-plane structure expresses the X-direction dimension through span parameters, thus efficiently and losslessly describing the three-dimensional features of the cross-sectional structure. Simultaneously, through the constraints and associations of the data tree, upper-level parameters can be fully shared by lower-level parameters, making the parameters of the specific structures involved in the calculation less verbose. This reduces the system overhead of updating, transferring, and managing massive elements in the lower layers of the tree structure.

[0008] Secondly, in order to meet the modeling requirements of different ship types and the corresponding standard verification requirements, the parameter model architecture is abstracted.

[0009] The abstraction process is as follows: multiple parameters, such as nodes, that do not change with ship type or specification updates are encapsulated sequentially and expressed in a unified manner as two-dimensional points and lines to represent the geometric and physical properties of the structure; parameters that change with ship type or specification updates are organized into XML files to express structural specification attributes; by separating static structural parameters from dynamic specification parameters, the definition of structural features does not depend on a certain specification, thereby decoupling the model from constraints and realizing easy reuse of the model and easy expansion of constraint types.

[0010] Finally, based on the standard library, automatic verification of ship structures is achieved.

[0011] The structural specifications for inland waterway vessels are complex, and consulting and mastering these specifications typically requires a significant amount of time and effort from designers. To address this, this invention analyzes relevant regulations and standards, constructing a specification library containing parameter sets, rule sets, and text sets. Module-based calls enable automation and efficiency in the verification of inland waterway vessel structures.

[0012] All parameters in the calculation formulas within the standard are numbered and stored according to the standard version, applicable ship type, and structural type, forming a parameter set; the connection relationships of the parameters in the formulas are converted into codes, which become a rule set; and the textual content describing the standard is entered using the standard clause number as an identifier, forming a text set.

[0013] During the verification process, based on the selected components and corresponding specifications, the corresponding XML parameter set from the specification library is dynamically configured and attached to the encapsulated structural parameter table. The corresponding rule set from the specification library is then loaded into the model data structure object via interface injection, thereby performing strength verification.

[0014] The present invention also provides a ship structural strength verification system, which is based on a model-view-controller framework and includes a view module, a model module, and a controller module; the view module, model module, and controller module are interconnected by signals, and the verification system performs the above-mentioned verification method.

[0015] The view module includes an input unit and a display unit. The input unit is used to interact with the user and respond to user commands and parameter inputs, while the display unit displays the verification results. The model module is used to store and manage the abstract structure model and specification library. The controller module is used for model verification calculation processing.

[0016] The present invention also provides a storage medium comprising a stored program, wherein the program executes the above-described verification method.

[0017] Compared with the prior art, the beneficial effects of the present invention include:

[0018] 1. Establish a hierarchical parametric model architecture for ships to achieve ship parameterization and parameter sharing, avoiding a large amount of repetitive modeling and parameter redefinition to simplify the modeling process; at the same time, the hierarchical, multi-level tree-like data structure of the whole ship-cross section-plate frame-component-node can improve the accuracy of modeling.

[0019] 2. When the parameter model architecture is abstracted, the separation of static structural parameters and dynamic specification parameters makes the definition of structural features independent of a certain specification, thereby decoupling the model from the constraints and realizing easy reuse of the model and easy expansion of constraint types.

[0020] 3. Compared with existing methods for parametric description of ship structures, this invention, based on a data sharing method between a custom hull structure data type and an XML structured description, decouples structural parameters from specification parameters and ensures the integrity and accuracy of specification parameters. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the ship parameter model architecture of the present invention.

[0022] Figure 2 This is a schematic diagram of the layered parameters of the inner bottom plate of the present invention.

[0023] Figure 3 This is a schematic diagram of the separation of the parametric model of the ship structure in this invention.

[0024] Figure 4 This is a schematic diagram of the deck component parameter configuration in this invention.

[0025] Figure 5 This is a class diagram of the computing module of the present invention.

[0026] Figure 6This is a flowchart of the local strength verification process of the present invention.

[0027] Figure 7 This is a schematic diagram of the top-level framework of the system of the present invention.

[0028] Figure 8 This is a schematic diagram of the system front-end interface of the present invention.

[0029] Figure 9 This is a schematic diagram of the midship cross-section modeling result of an example ship of the present invention. Implementation

[0030] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described clearly and completely below with reference to the accompanying drawings and embodiments. It should be understood that the described embodiments are merely some embodiments of an inland waterway vessel structure verification system according to this invention, and not all embodiments, and are not intended to limit the invention.

[0031] The strength verification items for ship hull structures can be divided into overall and local strength verification: local hull strength, longitudinal strength, and torsional strength verification. For inland waterway vessels, the main focus is on longitudinal strength and local strength. Among these, local strength involves the most parameters, affects the widest range of structures, and has the most detailed formulas in the specifications.

[0032] To avoid extensive repetitive modeling and parameter redefinition and simplify the modeling process, this invention designs a hierarchical parametric model architecture for ships, enabling ship parameterization as well as parameter sharing and transmission.

[0033] Ship hull structural models can be categorized by dimension into three-dimensional solid models and two-dimensional cross-sectional models. Solid models are more intuitive but cumbersome to model. Cross-sectional models, on the other hand, sacrifice clarity in the ship's length direction (longitudinal or X-axis direction), resulting in a simpler modeling process. Cross-sectional models are more suitable for local strength checks involving a large number of structural components, but to improve accuracy, the longitudinal properties of the structure are still indispensable in the calculations.

[0034] Therefore, the parametric model architecture of this invention is to deconstruct the three-dimensional hull in two dimensions, and to decompose the entire ship in sequence, that is, to establish a multi-layered, hierarchical ship structure tree based on two-dimensional points and lines.

[0035] like Figure 1 As shown, this is a specific embodiment of the parametric model architecture of the present invention. The parametric model architecture is a hierarchical, multi-level tree-like data structure of the whole ship-cross section-plate frame-component-node.

[0036] Among them, the entire ship layer has no structural entity, and the complex surface properties of the hull shape are discarded. Only the basic main dimension data are retained. At the same time, the longitudinal parameters of the nodes are discarded in exchange for efficient modeling speed. In the cross section coordinate system, it only has the meaning of Y and Z coordinates.

[0037] Using nodes, the intermediate layer is used to represent the ship's cross-sectional structure, which contains both shape and physical information. However, unlike the two-dimensional hull model, each cross-sectional object can establish a connection through positional parameters in the cross-sectional layer, confirming its distribution in the longitudinal direction of the hull. That is, each cross-section expresses the ship's length direction (longitudinal or X-coordinate direction) information through positional parameters such as rib position tables or station position tables, and maps it to the plate frame layer (component layer) and component layer of specific structural parts. The dimensional parameters in the ship's length direction are also preserved. Together with the basic components - nodes, the three-dimensional features of each structure within the cross-section are described non-destructively. That is, through the combination and association of nodes, the position and shape information of upper-level components and parts can be provided.

[0038] Considering the large amount of riverboat data, component trees and member trees are defined below the cross-section. These trees manage components within the cross-section and members on those components. The three data trees described above are tree-like data structures. They do not refer to a specific structure, but rather organize and manage all structural parameters hierarchically, planning the structural characteristics (geometric or physical) that each layer of parameters should express, thereby outlining the outer framework of the overall model.

[0039] Through the constraints and associations of the data tree, upper-level parameters can be fully shared by lower-level parameters, which makes the parameters of the specific structures involved in the calculation (which are generally at the bottom of the tree structure) no longer verbose.

[0040] Taking the inner bottom plate of a large hatchway vessel as an example, according to the "Code for Construction of Steel Inland Waterway Vessels 2016" (hereinafter referred to as "Inland Code 2016"), the plate thickness is specified in the following formula:

[0041]

[0042] In the formula: t is the standard thickness of the inner bottom plate, mm; s is the spacing between longitudinal ribs or ribs, mm; L is the length of the ship, mm; a is a dimensionless coefficient, determined by the navigation area; h is the calculated water column height, m, calculated according to formula (2); the other parameters are calculated from the same source as the spacing s.

[0043]

[0044] Where: Q is the maximum load capacity of the cargo hold, t; l is the length of the cargo hold bottom, m; b is the width of the cargo hold bottom, m; ν is the internal friction angle of bulk cargo, deg; v is the stowage factor, m. 3 / t, the same as the structure within the cross section, this value is considered the same.

[0045] For accurate verification, the inner base plate structure should possess all the aforementioned independent parameters during calculation. However, based on the model's layering, the parameter composition of the inner base plate is as shown in the appendix to the instruction manual. Figure 2 As shown, by appendix Figure 2As can be seen, under the action of the data tree, the inner bottom plate located in the component layer only needs to hold two parameters: thickness and spacing. This greatly shortens the model data length, provides a favorable foundation for the following model abstraction, and reduces the overhead of updating, transmitting and managing massive elements in the lower layer of the structure tree.

[0046] Inland waterway vessels are characterized by multiple ship types and numerous regulatory constraints. Multiple ship types imply complex and difficult-to-manage structural parameters, and because the primary focus is on local strength verification, more structural parameters are required for calculation compared to other verification projects. The above paper proposes a hierarchical parametric model architecture for ships, which enables ship parameterization and parameter sharing and transfer. However, the issue of multiple ship types requiring multiple regulations (multiple regulations with high update frequency, also implying that the same vessel may have different ship types) for verification still needs to be considered.

[0047] In view of this, in order to overcome the limitations of different ship types and different specification versions, this invention abstracts the above-mentioned parameter model architecture, as shown in the appendix to the specification. Figure 3 As shown, the specific process is as follows:

[0048] The process of sorting out the various parameters of the selected structure in the tree structure and encapsulating the multiple parameters that do not change with the ship type or specification update (hereinafter referred to as "static structural parameters") into specific structural objects for modeling and expression is the structural abstraction process, which results in an abstract structural model; the parameters that change with the ship type or specification update (hereinafter referred to as "dynamic specification parameters") are organized into an XML file, which is the parameter abstraction process.

[0049] When the dynamic specification parameters are configured in the abstract structural model, the entity analysis model can be obtained, and the entity analysis model can be directly used for verification calculations.

[0050] For effective model analysis, structures often need to be expressed using multiple feature parameters, especially at the component and assembly levels, which require both physical properties and cross-sectional shapes. However, too many parameters can easily lead to confusion in model management and analysis. Therefore, a custom structural feature is defined based on a DataTable. This involves encapsulating the various feature parameters of the selected structure sequentially into a data object, presenting a single feature to the outside world.

[0051] Structural abstraction aims to express various structures using common structural features, thereby resolving the configuration complexity caused by multiple ship types. This is mainly reflected in the definition and selection of component layers. It assumes that hull components can be classified according to general forms (such as skeletons and plates) and the main orientation, as specified in the specification. Figure 1 Five types of structural features are identified within the component layer. By capturing component nodes, the shape and position are automatically determined, thereby locating specialized structures such as deck side plates, which are further subdivided within the same category.

[0052] Taking a flat keel as an example, it is a special bottom plate that spans the mid-section of the ship's hull. It is structured with longitudinal plate features and is encapsulated by mid-section nodes and plate thickness. The system will automatically identify the node positions and apply flat keel constraints accordingly. Similarly, special components can be defined by combining multiple special parts.

[0053] Structural abstraction, based on the extraction of node geometric parameters, distinguishes components with different geometric nodes from similar components without requiring the addition of more cumbersome identification parameters for special structures, thus ensuring compatibility with basic structural features. Through structural abstraction, the tree structure provides a modeling scheme for inland waterway vessels of arbitrary hull types.

[0054] Parameter abstraction addresses multiple constraints and applies to all layers of the tree structure. Due to the uncertain relationship between the model and specification constraints, specification-related dynamic specification parameters are extracted from the structural features.

[0055] As per the instruction manual Figure 4 As shown, for deck frames, the static structural parameters are considered to include: basic component type, component members, and node member list. Depending on the ship type specifications, decks will extend into more subtypes; therefore, the subtypes and their associated cargo unevenness coefficients are dynamic specification parameters.

[0056] Analyzing and sorting out these specific parameters brought about by different specifications is quite tedious, but in this invention, the parameter set integrated by the specification library has already done this part of the work for us, and it has been classified and managed according to ship type and verification type.

[0057] Therefore, drawing on the interface-oriented approach, the ship parameter model is divided into an abstract structural model and a solid analysis model. (See attached manual.) Figure 3 As shown, the abstract structural model, possessing only static structural parameters, serves as an abstract representation of the entity analysis model. It provides a modeling interface for extracting constraints, allowing external models with fixed parameter architectures to freely interface with specifications and constraints from various versions and ship types. During the analysis and verification phase, the abstract structural model undergoes dynamic entityization. Specifically, based on different specifications selected by the designers or the system algorithm, the system dynamically loads the corresponding XML parameter sets from the specification library into the parameter table of the abstract structural model via file configuration, generating an entity analysis model for calculation.

[0058] The significance of parameter abstraction lies in the fact that by separating static structural parameters from dynamic specification parameters, the definition of structural features does not depend on a certain specification, thereby decoupling the model from constraints and realizing easy reuse of the model and easy expansion of constraint types.

[0059] The structural specifications for inland waterway vessels are complex, and consulting and mastering these specifications typically requires a significant amount of time and effort from designers. To address this, this invention analyzes relevant regulations and standards, constructing a specification library containing parameter sets, rule sets, and text sets. Module-based calls enable automation and efficiency in the verification of inland waterway vessel structures.

[0060] All parameters in the calculation formulas within the standard are numbered and stored according to the standard version, applicable ship type, and structural type, forming a parameter set; the connection relationships of the parameters in the formulas are converted into codes, which become a rule set; and the textual content describing the standard is entered using the standard clause number as an identifier, forming a text set.

[0061] After integrating the specification library, verification functionality can be developed, incorporated into the rule set, and automated verification can be achieved. The development of the verification module primarily considers providing underlying support for the aforementioned abstract compatibility model, i.e., decoupling the model module and verification module at the code level. Therefore, the verification module is designed based on the principle of inversion of control, and the module interface is written using dependency injection. That is, it is model-centric, selecting dependencies from multiple version specification calculation blocks to adapt to the model, rather than modifying model dependencies to adapt to different specification modules.

[0062] like Figure 5 As shown, dynamic loading in the code relies on the virtual class derivation technique in object-oriented programming. The base class interacts with the abstract structural model through a user interface. The various italicized functions in the base class (including model updates and calculations) are virtual functions, allowing the corresponding functionality in the subclass to be located during actual calls. This enables the same structure to be loaded according to different specifications for multi-type analysis (based on the 2016 or 2019 specifications), thus reusing the structural model. Simultaneously, the derivation technique also facilitates upgrades to the calculation module; most intuitively, specification updates only require rewriting the base class.

[0063] Finally, based on the above modules, models, and standard library, the local strength verification process in this invention is as follows: Figure 6 As shown.

[0064] Based on the aforementioned analytical model, the system first obtains information on all components to analyze the component verification types and accurately locates the verification rules through the structurally abstracted model. Once the calculation basis is determined, the system can perform comparative verification by combining the structural components' own properties. After all relevant data and calculation rules are prepared, the system checks the local strength on a component-by-component basis and finally outputs the parameter results, specification text, etc., in the form of a pop-up table. In addition, this program has a data checking function to ensure system robustness.

[0065] The present invention also provides a ship structure verification system, which is based on the Model-View-Controller (MVC) framework and integrates a modular and automated structure verification system.

[0066] From a practical perspective, this invention integrates an abstract model-based verification method within the MVC framework. Ultimately, the system comprises four modules: a front-end view, a front-end controller, a back-end processor, and a model, as follows: Figure 7 As shown.

[0067] The input and display functions located in the view layer have the following interface: Figure 8 As shown, the object panel and original model window are used to create the hull model and display the model parameters and result data read from the storage unit after calculation. The image window visually represents the cross-section. Error data generated in the calculation processing unit is also stored and output as warning messages to the information pool.

[0068] Preferably, the present invention also provides a storage medium comprising a stored program, wherein the program is used to perform the above-described strength verification process.

[0069] To verify the accuracy of the above methods and systems, the present invention conducted the following functional verification tests.

[0070] Based on the drawings of a certain approved bulk carrier and passenger ship, the "Internal Regulations 2016" were selected for modeling verification and testing. The midship section model and its main dimensions established using the system of this invention are as follows: Figure 9 (a) and Figure 9 As shown in (b).

[0071] Comparing the system calculation results with manual calculations in this invention, some results are shown below. Table 1 shows the unbiased results of automatic and manual calculations for bulk carriers, verifying the compatibility of multi-ship type structures. Table 2 shows the multi-ship type specification test results for a single model, and the unbiased results prove the accuracy of the multi-ship type specification calculations.

[0072] Table 1 Test Results of Special Structures

[0073]

[0074] Table 2. Test Results of Partial Multi-Type Specifications in the 2016 Internal Standards

[0075]

[0076]

[0077] The calculation tests of the 2016 and 2019 versions of the specifications were performed on the aforementioned bulk carriers, and the results are shown in Table 3. There were no calculation errors between the different versions of the specifications.

[0078] Table 3. Test Results of Partial Multi-Ship Type Specifications in the 2016 Internal Standards

[0079]

Claims

1. A method for verifying ship structures based on an abstract model of structural parameters, characterized in that, Includes the following steps: S100: Establish a hierarchical parametric model architecture for ships to achieve ship parameterization and parameter sharing; S200: The parametric model architecture is abstracted to meet the needs of modeling different ship types and verifying corresponding specifications. S300: Based on the standard library, it realizes automatic verification of ship structure; In step S200, the abstraction process is as follows: multiple parameters, including nodes, that do not change with ship type and specification updates are encapsulated in sequence and expressed in a unified manner as two-dimensional point and line forms to represent the structural geometry and physical properties; parameters that change with ship type or specification updates are organized into an XML file to express structural specification attributes. In step S100, the parameter model architecture is a hierarchical, multi-level tree-like data structure consisting of the whole ship, cross section, plate frame, component, and node. The node layer expresses the Y and Z coordinate information in the cross section coordinate system, the cross section expresses the X coordinate information through the rib parameters, and the in-plane structure expresses the X-direction dimension through the span parameter; Below the cross section, a component tree and a component tree are defined to manage the components within the cross section and the components on the components. Through the constraints and associations of the data tree, the upper-level parameters can be fully shared by the lower-level parameters. By separating static structural parameters from dynamic specification parameters, the model and constraints are decoupled. Step S300 includes: attaching the corresponding XML parameter set from the specification library to the encapsulated structure parameter table through dynamic configuration; and loading the corresponding rule set from the specification library into the data structure object of the above parameter model architecture through interface injection.

2. The ship structure verification method based on a structural parameter abstract model as described in claim 1, characterized in that, The specification library includes a parameter set, a rule set, and a text set. The parameter set is formed by numbering and storing the parameters of all calculation formulas in the specification according to the specification version, applicable ship type, and structural type. The rule set is formed by converting the connection relationships of the parameters in the formula into code classes. The text set is formed by entering the text content of the specification description using the specification clause number as an identifier.

3. The ship structure verification method based on a structural parameter abstract model as described in claim 1, characterized in that, The verification method is based on a verification system, which is based on a model-view-controller framework.

4. A ship structure verification system, characterized in that, The verification system is based on a model-view-controller framework, which includes a view module, a model module, and a controller module; the view module, model module, and controller module are interconnected by signals, and the verification system performs the method described in any one of claims 1 to 3.

5. A ship structure verification system as described in claim 4, characterized in that, The view module includes an input unit and a display unit. The input unit is used to interact with the user and respond to user commands and parameter inputs, while the display unit displays the verification results. The model module is used to store and manage abstract structural models and specification libraries; the controller module is used for model verification calculations.

6. A storage medium, characterized in that, The storage medium includes a stored program, wherein the program executes the method according to any one of claims 1 to 3.

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