MATLAB-based finite element model dynamic analysis and conversion method

Abstract

The invention provides a finite element model dynamic analysis and conversion method and system based on MATLAB. The method comprises the steps that an Abaqus INP file is read, and node coordinates, unit connection relations, unit grouping and section parameters are dynamically recognized and extracted; aiming at a shell unit, analyzing a node connection relation of the shell unit, establishing a mapping table from unit ID to thickness, generating a unique thickness list, writing the unique thickness list into SECTIONHELL of LS-DYNA, and forcibly setting the thickness values T1-T4 to be the same; the method comprises the following steps: aiming at a beam unit, analyzing a generate parameter in Elset to generate a continuous unit ID sequence, extracting a section parameter according to Beam Section, and mapping the section parameter to SECTIONBEAM of LS-DYNA; and an LS-DYNA K file is generated according to the sequence of the nodes, the shell units and the beam units, and corresponding section attributes and grouping information are associated. According to the method, the finite element model file of Abaqus is dynamically analyzed, complete reservation of unit grouping information, accurate extraction of complex section parameters and consistency processing of shell unit thickness are achieved, the unit grouping information is efficiently and accurately converted into the K file format of LS-DYNA, and the efficiency and reliability of multi-software co-simulation in the ship and ocean engineering field are improved.

Description

Technical Field

[0001] This invention relates to the field of shipbuilding and marine engineering technology, and more particularly to a dynamic analysis and transformation method for finite element models based on MATLAB. Background Technology

[0002] Numerical simulation is an indispensable tool in modern engineering design and analysis, especially in the field of blast and shock resistance research for ships. It plays a crucial role in comprehensively analyzing the damage to ship structures under near-field explosions and the impact of far-field explosions. Currently, commonly used commercial software for numerical simulation in this field includes ABAQUS and LS-DYNA. ABAQUS, with its powerful acoustic-structure interaction method, performs excellently in calculating far-field explosion impacts; while LS-DYNA, with its efficient fluid-structure interaction method, is superior in near-field damage calculations. However, the data structures of the two software programs are incompatible, which poses a challenge to engineering applications that require combining the advantages of both for complex operational condition analysis.

[0003] In existing technologies, the conversion of Abaqus models to LS-DYNA mainly relies on manual editing or simple script tools. While manual editing can achieve a certain degree of conversion, it is extremely inefficient. Engineers need to parse the INP file line by line and manually process node, element, and section parameters, which can take several days and is prone to errors. Traditional script tools can extract basic geometric data, but they have significant limitations. They cannot recognize complex keywords (such as implicit generation rules of Elset or irregular section parameters of Beam Section), resulting in the loss of grouping information for key structures such as hull ribs and keels, simplification of the moment of inertia parameters of irregular stiffeners, and numerical divergence caused by thickness fluctuations in thin shell elements. Ultimately, this leads to a significant decrease in the accuracy of simulations such as collisions and wave impacts. In addition, for large-scale models containing tens of thousands of elements, such as marine platforms, manual unfolding of implicit sequences is inefficient, and the memory management deficiencies of traditional tools cause frequent crashes during the conversion process, severely restricting the engineering applications of multi-software collaborative design and complex working condition analysis.

[0004] Existing technologies face significant bottlenecks in their application in the field of shipbuilding and ocean engineering. For example, in ship collision simulation, traditional methods neglect… Elset's generate parameters require manual input of thousands of element IDs, taking over 10 hours and with a high error rate. For ARBITRARY beam sections with irregular stiffeners in ship hulls, existing tools only extract the cross-sectional area while ignoring the moment of inertia parameter, leading to severe deviations in stiffness calculations and significant discrepancies between simulation results and physical experiments. While commercial plugins partially support format conversion, they do not enforce uniformity of LS-DYNA's T1-T4 parameters when directly copying shell element thickness. This causes stress singularities in thin-shell hulls due to local thickness fluctuations during dynamic impacts, resulting in most simulation cases being interrupted due to numerical divergence. Furthermore, when offshore platform models contain defined truss elements, traditional methods require manual expansion into thousands of explicit IDs, taking several hours and prone to omissions or duplications. Simple scripts, due to inefficient memory management, consume too much memory when processing models with millions or even tens of millions of elements, causing frequent crashes on ordinary workstations. These problems extend the simulation cycle in the field of shipbuilding and ocean engineering, heavily rely on manual experience for correction, and hinder efficient iteration and multidisciplinary collaborative design for complex conditions. Summary of the Invention

[0005] To address the aforementioned technical problems, this paper provides a MATLAB-based dynamic analysis and conversion method and system for finite element models. This method efficiently and accurately converts Abaqus INP files into LS-DYNA K file format. Through dynamic analysis technology, it preserves element grouping information, accurately extracts section parameters, and enforces shell element thickness consistency. This solves problems such as poor format compatibility, loss of grouping information, insufficient handling of complex sections, and low computational efficiency in existing technologies, significantly improving the efficiency and accuracy of multi-software collaborative simulation in the field of shipbuilding and ocean engineering.

[0006] The technical means employed in this invention are as follows: A MATLAB-based method for dynamic analysis and transformation of finite element models includes: S1. Read the Abaqus INP file, dynamically identify and extract node coordinates, element connection relationships, element grouping and section parameters; S2. For shell elements, parse their node connections and establish a mapping table from element ID to thickness. After generating a unique thickness list, write it into LS-DYNA. SECTION_SHELL forces the thickness values ​​of T1-T4 to be the same; S3. For beam elements, the `generate` parameter in the Elset is parsed to generate a continuous element ID sequence, and the section parameters are extracted from the BeamSection and then mapped to LS-DYNA. SECTION_BEAM; S4. Generate LS-DYNA K files in the order of nodes, shell elements, and beam elements, and associate the corresponding section properties and grouping information.

[0007] Further, in step S1, the dynamic identification includes: Matching Node, Element, Elset, Shell Section using regular expressions Beam Section keywords; For those containing the generate parameter Elset performs implicit rule parsing to generate a continuous sequence of unit IDs, avoiding manual input of each item.

[0008] Furthermore, in step S2, the processing of the shell unit specifically includes: Identify the S4R and S3 shell element types and their node connection relationships; Extract the thickness values ​​from the Shell Section and construct a unique thickness list. When writing to SECTION_SHELL, force T1=T2=T3=T4 to eliminate thickness fluctuations.

[0009] Furthermore, in step S3, the grouping and section processing of beam elements specifically include: Create the corresponding PART in LS-DYNA based on the Elset grouping information; Identification The section type in the Beam Section (such as ARBITRARY type beam section) is automatically extracted for area and moment of inertia parameters and adapted to the Hughes-Liu beam model (ELFORM=2) format in LS-DYNA.

[0010] Furthermore, in step S3, the beam section mapping for the beam element specifically includes: when When the Beam Section is an irregular cross section, its moment of inertia parameter is calculated by double integration, and the consistency of the cross section properties is verified. Preserve the original grouping and section binding relationship, and associate it with the PART number when generating ELEMENT_BEAM.

[0011] Further, in step S4, the generation order of the LS-DYNA K files is as follows: Prioritize writing the node coordinates (NODE) ​​and shell element coordinates (ELEMENT_SHELL), then write them to the beam elements in groups. ELEMENT_BEAM; Bind SECTION_SHELL and SECTION_BEAM to shell elements and beam elements respectively to ensure the integrity of section properties and grouping information.

[0012] This invention also provides a MATLAB-based dynamic analysis and conversion system for finite element models, implemented based on the aforementioned MATLAB-based dynamic analysis and conversion method for finite element models, comprising: The file parsing module is used to dynamically identify keywords in Abaqus INP files and construct structured data. The shell element processing module is used to force uniform shell element thickness and generate... SECTION_SHELL; The beam element processing module is used to parse the generate sequence and irregular section parameters to generate PART and SECTION_BEAM. The K-file generation module is used to output LS-DYNA compatible K-files in a preset order.

[0013] Furthermore, the system is applied in the field of shipbuilding and marine engineering, specifically for: The Abaqus to LS-DYNA conversion of hull shell units (decks, bulkheads) supports collision and wave impact simulation; The grouping and preservation of complex beam elements (ribs, keels) and the mapping of section properties meet the requirements for strength assessment under multiple working conditions.

[0014] Compared with the prior art, the present invention has the following advantages: 1. This invention can automatically parse Abaqus Elset keywords (including explicit lists or implicit generation rules), dynamically generate continuous unit ID sequences, and create corresponding PARTs in LS-DYNA. SECTION_BEAM ensures that the binding relationship between the original grouping information and the section attributes is completely transmitted, avoiding the loss of grouping information caused by manual secondary modeling, providing convenience for subsequent attribute assignment, and significantly improving the efficiency and accuracy of multi-software collaborative simulation.

[0015] 2. This invention addresses shell unit thickness processing by generating a unique thickness list. SECTION_SHELL forces T1-T4 to have the same thickness value, effectively avoiding stress singularities caused by local thickness fluctuations, ensuring the numerical stability of the LS-DYNA shell element model, thereby guaranteeing the simulation stability of thin-shell hulls under complex working conditions such as collisions and wave impacts, and improving the reliability and accuracy of the simulation.

[0016] 3. This invention can automatically identify Abaqus Beam Sections (such as ARBITRARY type), extract parameters such as area and moment of inertia, and map them to the LS-DYNA SECTION_BEAM keyword, compatible with the format requirements of Hughes-Liu beam models (ELFORM=2). This technique accurately extracts key parameters such as moment of inertia, adapting to the nonlinear analysis needs of complex structures such as irregular stiffeners and keels, significantly improving the simulation accuracy of complex structures, and making the simulation results closer to real physical phenomena.

[0017] 4. In the process of generating K-files, this invention strictly follows the order of nodes, shell elements, and beam elements. This orderly generation method not only ensures the standardization of the file format but also optimizes the data processing flow, which greatly improves the conversion efficiency of large-scale marine platform models. The processing speed is much higher than that of manual operation, effectively solving the problems of low efficiency and excessive memory consumption leading to frequent crashes when processing large-scale models using traditional methods. This provides reliable technical support for the full life cycle simulation of ships and marine equipment.

[0018] In summary, this invention comprehensively solves the key pain points of existing technologies in the conversion process from Abaqus to LS-DYNA, achieving high-precision and high-efficiency model transfer. It provides an efficient and reliable solution for complex working condition analysis, multidisciplinary collaborative design, and full life cycle simulation in the field of shipbuilding and marine engineering, promoting the development and application of numerical simulation technology in this field. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a flowchart of the method of the present invention. Detailed Implementation

[0021] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0022] It should be noted that the terms "comprising" and "having" and any variations thereof in the specification, claims and accompanying drawings of this invention are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are explicitly listed, but may include other steps or units that are not explicitly listed or that are inherent to such processes, methods, products or devices.

[0023] like Figure 1 As shown, this invention provides a dynamic analysis and transformation method for finite element models based on MATLAB, including: S1. Read the Abaqus INP file, dynamically identify and extract node coordinates, element connection relationships, element grouping and section parameters; S2. For shell elements, parse their node connections and establish a mapping table from element ID to thickness. After generating a unique thickness list, write it into LS-DYNA. SECTION_SHELL forces the thickness values ​​of T1-T4 to be the same; S3. For beam elements, the `generate` parameter in the Elset is parsed to generate a continuous element ID sequence, and the section parameters are extracted from the BeamSection and then mapped to LS-DYNA. SECTION_BEAM; S4. Generate LS-DYNA K files in the order of nodes, shell elements, and beam elements, and associate the corresponding section properties and grouping information.

[0024] In a specific implementation, as a preferred embodiment of the present invention, step S1, the dynamic identification includes: Matching Node, Element, Elset, and Shell Section using regular expressions. Beam Section keywords; For those containing the generate parameter Elset performs implicit rule parsing to generate a continuous sequence of unit IDs (such as start_id:step:end_id), avoiding manual input of each item.

[0025] In a specific implementation, as a preferred embodiment of the present invention, step S2, the processing of the shell unit specifically includes: Identify the S4R and S3 shell element types and their node connection relationships; Extract the thickness values ​​from the Shell Section and construct a unique thickness list. When writing to SECTION_SHELL, force T1=T2=T3=T4 to eliminate thickness fluctuations.

[0026] In a specific implementation, as a preferred embodiment of the present invention, step S3, specifically the grouping and section processing of beam elements, includes: Create the corresponding PART in LS-DYNA based on the Elset grouping information; Identification The section type in the Beam Section (such as ARBITRARY type beam section) is automatically extracted for area and moment of inertia parameters, and adapted to the Hughes-Liu beam model (ELFORM=1 or 2) format in LS-DYNA.

[0027] In a specific implementation, as a preferred embodiment of the present invention, step S3, specifically the beam section mapping for the beam element, includes: when When the Beam Section is an irregular cross section, its moment of inertia parameter is calculated by double integration, and the consistency of the cross section properties is verified. Preserve the original grouping and section binding relationship, and associate it with the PART number when generating ELEMENT_BEAM.

[0028] In a specific implementation, as a preferred embodiment of the present invention, the generation order of the LS-DYNA K files in step S4 is as follows: Prioritize writing the node coordinates (NODE) ​​and shell element coordinates (ELEMENT_SHELL), then write them to the beam elements in groups. ELEMENT_BEAM; Bind SECTION_SHELL and SECTION_BEAM to shell elements and beam elements respectively to ensure the integrity of section properties and grouping information.

[0029] This invention also provides a MATLAB-based dynamic analysis and conversion system for finite element models, implemented based on the aforementioned MATLAB-based dynamic analysis and conversion method for finite element models, comprising: The file parsing module is used to dynamically identify keywords in Abaqus INP files and construct structured data. The shell element processing module is used to force uniform shell element thickness and generate... SECTION_SHELL; The beam element processing module is used to parse the generate sequence and irregular section parameters to generate PART and SECTION_BEAM. The K-file generation module is used to output LS-DYNA compatible K-files in a preset order.

[0030] In a specific implementation, as a preferred embodiment of the present invention, the system is applied in the field of shipbuilding and marine engineering, specifically for: The Abaqus to LS-DYNA conversion of hull shell units (decks, bulkheads) supports collision and wave impact simulation; The grouping and preservation of complex beam elements (ribs, keels) and the mapping of section properties meet the requirements for strength assessment under multiple working conditions.

[0031] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A dynamic analytical and transformation method for finite element models based on MATLAB, characterized in that, include: S1. Read the Abaqus INP file, dynamically identify and extract node coordinates, element connection relationships, element grouping and section parameters; S2. For shell elements, parse their node connections and establish a mapping table from element ID to thickness. After generating a unique thickness list, write it into LS-DYNA. SECTION_SHELL forces the thickness values ​​of T1-T4 to be the same; S3. For beam elements, the `generate` parameter in the Elset is parsed to generate a continuous element ID sequence, and the section parameters are extracted from the BeamSection and then mapped to LS-DYNA. SECTION_BEAM; S4. Generate LS-DYNA K files in the order of nodes, shell elements, and beam elements, and associate the corresponding section properties and grouping information.

2. The method for dynamic analysis and transformation of finite element models based on MATLAB according to claim 1, characterized in that, In step S1, the dynamic identification includes: Matching Node, Element, Elset, and Shell Section using regular expressions. Beam Section keywords; For those containing the generate parameter Elset performs implicit rule parsing to generate a continuous sequence of unit IDs, avoiding manual input of each item.

3. The method for dynamic analysis and transformation of finite element models based on MATLAB according to claim 1, characterized in that, In step S2, the processing of the shell unit specifically includes: Identify the S4R and S3 shell element types and their node connection relationships; Extract the thickness values ​​from the Shell Section and construct a unique thickness list. When writing to SECTION_SHELL, force T1=T2=T3=T4 to eliminate thickness fluctuations.

4. The method for dynamic analysis and transformation of finite element models based on MATLAB according to claim 1, characterized in that, Step S3 specifically includes the grouping and section treatment of beam elements: Create the corresponding PART in LS-DYNA based on the Elset grouping information; Identification The section type in the Beam Section is automatically extracted, and the area and moment of inertia parameters are adapted to the Hughes-Liu beam model format of LS-DYNA.

5. The method for dynamic analysis and transformation of finite element models based on MATLAB according to claim 1, characterized in that, In step S3, the beam section mapping for the beam element specifically includes: when When the Beam Section is an irregular cross section, its moment of inertia parameter is calculated by double integration, and the consistency of the cross section properties is verified. Preserve the original grouping and section binding relationship, and associate it with the PART number when generating ELEMENT_BEAM.

6. The method for dynamic analysis and transformation of finite element models based on MATLAB according to claim 1, characterized in that, In step S4, the generation order of the LS-DYNA K files is as follows: Prioritize writing the node coordinates (NODE) ​​and shell element coordinates (ELEMENT_SHELL), then write them to the beam elements in groups. ELEMENT_BEAM; Bind SECTION_SHELL and SECTION_BEAM to shell elements and beam elements respectively to ensure the integrity of section properties and grouping information.

7. A MATLAB-based finite element model dynamic analysis and conversion system based on the MATLAB-based finite element model dynamic analysis and conversion method described in any one of claims 1-6, characterized in that, include: The file parsing module is used to dynamically identify keywords in Abaqus INP files and construct structured data. The shell element processing module is used to force uniform shell element thickness and generate... SECTION_SHELL; The beam element processing module is used to parse the generate sequence and irregular section parameters to generate PART and SECTION_BEAM. The K-file generation module is used to output LS-DYNA compatible K-files in a preset order.

8. The MATLAB-based dynamic analysis and transformation system for finite element models according to claim 7, characterized in that, The system is applied in the field of shipbuilding and marine engineering, specifically for: Abaqus to LS-DYNA conversion of hull shell elements supports collision and wave impact simulation; The grouping and preservation of complex beam elements and the mapping of section properties meet the requirements for strength assessment under multiple working conditions.

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