Abaqus-based design method for steel structure raw coal hopper of thermal power plant

Abstract

The present application relates to the technical field of electric power engineering, and more particularly to a thermal power plant steel structure raw coal hopper design method based on ABAQUS, comprising: establishing a material and component section database of a raw coal hopper structure model; establishing a three-dimensional shell model using a reference plane and a line, shell generation algorithm; creating a setting position of a support and a stiffening rib; completing a modeling step except loading a nonlinear load, generating an inp model file; enabling a nonlinear load module development program, updating the inp model file; executing an analysis step and obtaining a result; when the result meets the design requirements, outputting a calculation result and forming a complete calculation book; when the result does not meet the design requirements, repeating the foregoing steps for structure design iteration until the calculation result meets the design requirements, and then outputting the calculation result and forming the complete calculation book. Through the method, the modeling efficiency and load application accuracy of a complex raw coal hopper structure are improved, and a standardized design process is formed.

Description

Technical Field

[0001] This invention relates to the field of power engineering technology, and in particular to a design method for raw coal hoppers in steel structures of thermal power plants based on ABAQUS. Background Technology

[0002] The steel-structured raw coal hopper in a thermal power plant is a key piece of equipment in the boiler's coal feeding and storage system. It primarily receives raw coal from the coal bunker and transports it to downstream coal feeding equipment. Its structure typically consists of a welded upper cylindrical section, a middle transition section, and a lower conical hopper section, making it a typical special steel structure subjected to heavy loads and high friction. The inner wall of the raw coal hopper must withstand the normal pressure and tangential friction generated by the stored raw coal. These two loads vary non-linearly with the coal depth, and the rationality of its structural design is directly related to the reliability of the coal conveying system and the stability of power generation.

[0003] Currently, with the increasing capacity of thermal power plant units and the diversification of coal hopper structures, more and more engineering designs are using finite element method (FEM) software for structural analysis of raw coal hoppers. Taking general-purpose FEM software such as ABAQUS, ANSYS, and MIDAS as examples, designers typically need to create a three-dimensional shell model of the coal hopper in the software based on design data, define material properties and section parameters, mesh the hopper, and apply boundary conditions. Regarding loads, designers need to calculate the normal pressure and tangential friction of the coal on the cylinder wall according to relevant design specifications, and then apply these loads one by one to the corresponding positions of the model in the form of surface loads or nodal loads. After completing the above preprocessing work, the calculation and analysis are submitted, and parameters such as wall thickness and stiffening rib arrangement are adjusted based on the stress and displacement calculation results, iterating repeatedly until the specifications are met.

[0004] However, the design process based on general-purpose finite element software still faces some difficulties in practical engineering applications. On the one hand, to meet the process requirements of smooth material feeding, volume adaptation, and spatial arrangement, the structural forms of raw coal hoppers are becoming increasingly complex, with geometric structures such as variable curvature arc-shaped cylinder walls, porous irregular funnels, and asymmetric transition sections emerging. In the finite element preprocessing stage, the establishment of such complex surface models requires designers to complete a large amount of spatial node positioning work, resulting in a long modeling cycle. On the other hand, the normal pressure and tangential friction force borne by the inner wall of the raw coal hopper vary nonlinearly with the coal depth, and their distribution patterns also differ in cylinder wall sections with different inclination angles. Currently, the common practice in engineering is to manually calculate the pressure values ​​of each zone and then apply loads to each region of the model one by one. For cases with irregular geometry or where multiple coal types and multiple working conditions need to be considered simultaneously, the operation is cumbersome and prone to introducing human error. In addition, for raw coal hoppers of different coal types, volumes, and geometric shapes, the existing design process involves a lot of repetitive work in model establishment and load application, and a systematic parametric processing method has not yet been formed. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the purpose of this invention is to integrate two main parts: an efficient ABAQUS-based modeling scheme and a nonlinear load module development program. This provides an ABAQUS-based design method for raw coal hoppers in thermal power plants, improving the modeling efficiency and load application accuracy of complex raw coal hopper structures, and establishing a standardized design process.

[0006] To achieve the above objectives, the embodiments of the present invention provide the following technical solutions: An embodiment of the present invention provides a design method for a steel structure raw coal hopper in a thermal power plant based on ABAQUS, comprising the following steps: Establish a database of materials and component cross-sections for the raw coal hopper structural model; A three-dimensional shell model is established using a reference plane and line / shell generation algorithm. Create the settings for supports and stiffening ribs; Complete the modeling steps except for applying nonlinear loads, and generate the inp model file; Enable the nonlinear load module development program and update the inp model file; Perform the analysis step and obtain the results; Judge the calculation results. When the results meet the design requirements, output the calculation results and generate a complete calculation report. If the results do not meet the design requirements, repeat the aforementioned steps to iterate the structural design until the calculation results meet the design requirements, then output the calculation results and form a complete calculation report.

[0007] As a further technical solution, establishing a material and component section database for the raw coal hopper structural model includes: defining material properties and component section types, wherein the materials are Q235B and Q355B steel, and the component section types include angle steel, channel steel, T-shaped steel beams, and combined stiffening ribs welded from rectangular steel plates.

[0008] As a further technical solution, the establishment of a three-dimensional shell model using a reference plane and line / shell generation algorithm includes: establishing a reference plane at key elevations based on design data, creating corresponding cylinder wall contour lines within the plane, and using a shell generation algorithm to create a three-dimensional shell model from the cylinder wall contour lines; the shell generation algorithm includes extrusion, rotation, sweeping, planarization, and lofting.

[0009] As a further technical solution, lofting is achieved by defining the outlines of the upper and lower cylinder walls and the guide path to generate a curved surface.

[0010] As a further technical solution, the location of the supports and stiffening ribs is created by dividing the shell model using a reference plane.

[0011] As a further technical solution, the modeling steps, excluding the application of nonlinear loads, include: assigning element material and section properties, meshing, creating analysis steps, defining constraints, and applying linear loads; the linear loads include circumferentially distributed loads at the top and bottom edges of the structure.

[0012] As a further technical solution, updating the inp model file using the nonlinear load module development program includes: Obtain input parameters and verify their accuracy; Read the inp model file and generate the cell matrix and node matrix of the cell set; Determine the element tilt type. When the element type is tilted, calculate the normal stress, tangential stress, and vector of each tilted element. When the element type is vertical, calculate the normal stress of each vertical element. Insert the calculation results into a fixed string to generate an inp statement for applying nonlinear loads; Copy the inp model file, insert the generated inp statements into the copied document, and save it to complete the update of the inp model file.

[0013] As a further technical solution, after determining the tilt type of the unit, the calculation of the normal stress and tangential stress on the unit specifically includes: calculating the normal stress of the tilted unit based on the angle between the calculated unit and the horizontal plane, the lateral pressure coefficient, and the vertical pressure at the calculated section; calculating the tangential stress of the tilted unit based on the vertical pressure at the calculated section, the lateral pressure coefficient, and the angle between the calculated unit and the horizontal plane; and calculating the normal stress of the vertical unit based on the lateral pressure coefficient of the vertical cylinder wall, the density of the coal, and the distance from the top surface of the coal to the calculated section.

[0014] As a further technical solution, performing the analysis step and obtaining the results includes: importing the updated inp model file into the CAE module, or directly calling the ABAQUS solver, performing the elastoplastic analysis step, and obtaining the stress and displacement contour plots of the structural model; when performing stress calculations, the load partial factors are taken according to the ultimate limit state of bearing capacity; when performing deformation calculations, the load partial factors are taken according to the serviceability limit state.

[0015] As a further technical solution, outputting calculation results and forming a complete calculation report includes: importing the component information, load information, constraint conditions and calculation cloud diagram results from the calculation model into a pre-prepared calculation report template to form a complete calculation report.

[0016] One or more technical solutions provided in the embodiments of the present invention have at least the following technical effects or advantages: This method utilizes reference planes and line / shell generation algorithms to establish a 3D shell model, transforming complex spatial node positioning into reference plane design and contour line drawing at key elevations, thus lowering the operational threshold for modeling. Multiple forms of shell generation algorithms can cover the modeling needs of various complex geometries. Secondly, a nonlinear load module development program is used to update the .inp model file. This program can comprehensively calculate the normal and tangential stresses on the cylinder wall and automatically generate load application statements, replacing the traditional method of manually calculating and applying zoned pressure values ​​one by one, avoiding deviations in human calculation and operation. Finally, by establishing a database, parametric modeling, procedural loading, iterative design, and templated output, the entire design process is linked into a reusable, standardized closed loop. The database allows for parametric selection and replacement of materials and sections, and the aforementioned parametric methods can be reused to adjust design parameters during iterative design steps, eliminating the need to start from scratch for each project. These three improvements work together to achieve improved modeling efficiency, accurate load application, and standardized design processes.

[0017] Advantages of additional aspects of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0018] 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. The drawings described below are only some embodiments recorded in the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. In addition, the dimensions or spacing between the components are exaggerated to show the position of each component, and the schematic diagrams are for illustrative purposes only.

[0019] Figure 1 This is a flowchart of the design method provided in an embodiment of the present invention; Figure 2 This is a logic diagram of the nonlinear load module development program provided in this embodiment of the invention; Detailed Implementation To more clearly illustrate the technical solutions of the embodiments in this specification, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are merely some examples or embodiments of this specification. For those skilled in the art, these drawings can be applied to other similar scenarios without creative effort. Unless obvious from the linguistic context or otherwise specified, the same reference numerals in the drawings represent the same structures or operations.

[0020] Generally speaking, the terms "comprising" and "including" only indicate that the steps and elements are explicitly identified, and these steps and elements do not constitute an exclusive list. The method or apparatus may also include other steps or elements.

[0021] The steel-structured raw coal hopper in a thermal power plant is a key component responsible for coal feeding, storage, transportation, buffering, and regulation in the boiler. Its structure typically consists of a welded upper cylindrical section, a middle transition section, and a lower conical hopper section, making it a typical special steel structure subjected to heavy loads and high friction. The rationality and safety of its structural design directly affect the reliability of the coal conveying system and the stability of power generation. However, in engineering practice, the design of the raw coal hopper structure still has the following prominent problems: 1. The complex structure and shape make modeling difficult. To meet the process requirements of smooth material feeding, volume adaptation, and spatial arrangement, the raw coal hopper exhibits diverse structural features, such as complex geometric structures like variable curvature arc-shaped cylinder walls, porous irregular-shaped funnels, and asymmetric transition sections. The complex curved surface shape of the cylinder wall significantly increases the preprocessing difficulty and modeling cycle of the finite element model.

[0022] 2. Load application is difficult, and nonlinear distribution is hard to simulate accurately. The normal pressure and tangential friction force of the raw coal stored on the inner wall of the raw coal hopper are not uniformly distributed, but rather vary nonlinearly with depth (vertical distance from the top surface of the hopper). In finite element analysis, manually calculating the pressure values ​​of each zone and then applying the load to each region of the model is cumbersome, has low loading accuracy, and is inefficient. Especially when the geometry of the coal hopper is irregular or multiple coal types and multiple working conditions need to be considered simultaneously, traditional methods are prone to introducing human calculation errors, affecting the reliability of the design results.

[0023] 3. Low level of parametric modeling and lack of standardized design processes. For raw coal hoppers of different coal types, volumes, and geometries, existing technologies have not yet developed systematic parametric modeling and nonlinear load application methods. Designers must repeatedly perform node spatial positioning, component definition, and load calculation and application for each project, resulting in a repetitive and cumbersome design process that restricts design efficiency and optimization iteration capabilities.

[0024] Based on this, in a typical embodiment of this disclosure, a design method for a raw coal hopper steel structure in a thermal power plant based on ABAQUS is provided, including the following steps: establishing a database of materials and component sections for the raw coal hopper structural model; establishing a three-dimensional shell model using reference plane and line / shell generation algorithms; creating the placement positions of supports and stiffening ribs; completing the modeling steps except for loading nonlinear loads, and generating an inp model file; enabling the nonlinear load module development program and updating the inp model file; executing the analysis step and obtaining the results; judging the calculation results, and when the results meet the design requirements, outputting the calculation results and forming a complete calculation report; when the results do not meet the design requirements, repeating the aforementioned steps to iterate the structural design until the calculation results meet the design requirements, and then outputting the calculation results and forming a complete calculation report.

[0025] This method establishes a database of materials and component sections, enabling parametric selection and replacement during subsequent design or iteration processes, avoiding the repetitive work of defining material and section types. A three-dimensional shell model is built using a reference plane and line / shell generation algorithm, transforming the complex spatial node positioning problem in traditional methods into a contour line design problem within the reference plane, aligning with the original expression of the design data. The locations of supports and stiffeners are created by segmenting the shell model, providing a positional basis for subsequent constraint and load application. Modeling steps other than nonlinear loads are completed, and an .inp model file is generated. The preprocessing work is divided into two stages: linear loads are applied at this stage, while nonlinear loads are handled by a dedicated program. The nonlinear load module development program is used to update the .inp model file. This program can comprehensively calculate the normal and tangential stresses on the shell wall and automatically generate .inp statements for the ABAQUS load module, replacing the traditional method of manually calculating and applying zoned pressure values ​​one by one. The analysis step is executed, and the results are obtained through elastoplastic analysis to obtain stress and displacement contour maps. After judging the calculation results, if the design requirements are met, the calculation report is output; otherwise, iterative design is performed. During the iteration process, parametric methods can be used to adjust the cylinder wall thickness, the position of stiffening ribs, and the cross-sectional type, etc., until the requirements are met.

[0026] In the above steps, the establishment of the database provides a data foundation for parametric iteration, the shell modeling method provides a technical means for the rapid generation of complex geometric structures, and the nonlinear load module development program provides an automated tool for accurately simulating load distribution. The synergistic effect of the three makes the entire design process a reusable and standardized closed loop.

[0027] When establishing a database of materials and component sections for the raw coal hopper structural model, it is necessary to specify the types of materials and components to be used so that parametric selection and replacement can be carried out in subsequent design.

[0028] Based on this, the establishment of the material and component section database for the raw coal hopper structural model includes: defining material properties and component section types. The materials are Q235B and Q355B steel, and the component section types include angle steel, channel steel, T-shaped steel beams, and combined stiffening ribs welded from rectangular steel plates.

[0029] The main structure of the raw coal hopper in a thermal power plant typically uses Q355B steel, a commonly used steel grade in power plant civil engineering design. Regarding component cross-section types, angle steel such as L100×10, channel steel such as [20a and [14a), and T-beams such as TM225×300 and TN125×125 are all common steel profiles used in engineering. Combined stiffening ribs welded from rectangular steel plates are used to meet the reinforcement requirements of special areas. By pre-defining the above materials and cross-section types and forming a database, designers can directly select appropriate cross-sections from the database during the initial and iterative design processes, eliminating the need to re-enter cross-section parameters each time, thus improving design efficiency.

[0030] When using reference planes and line / shell generation algorithms to build a three-dimensional shell model, the specific modeling process needs to be further clarified so that those skilled in the art can implement it.

[0031] Based on this, the establishment of a three-dimensional shell model using a reference plane and line / shell generation algorithm includes: establishing a reference plane at key elevations according to design data, creating corresponding cylinder wall contour lines within the plane, and using a shell generation algorithm to create a three-dimensional shell model from the cylinder wall contour lines; the shell generation algorithm includes extrusion, rotation, sweeping, planarization, and lofting.

[0032] Critical elevations refer to design-significant elevation locations such as the top and bottom of the coal hopper, the height of supports, and the connection points between the top and bottom of transition sections. Design documents typically provide the cylinder wall outline at each elevation in the form of a plan view. After establishing reference planes at these elevations, the outlines from the design documents are directly drawn onto these reference planes, thus transforming the node positioning problem in three-dimensional space into a contour drawing problem in a two-dimensional plane. Among shell generation algorithms, extrusion is suitable for uniform cross-section cylinder sections, rotation for structures of revolution, sweeping for cross-sections that change along a path, planarization for flat plate components, and lofting for transition sections with different upper and lower cross-sections. These various algorithms can be flexibly selected based on the geometric characteristics of different sections of the original coal hopper, covering the modeling needs of various complex structures.

[0033] Lofting algorithms have unique advantages in handling complex geometries, and are particularly suitable for sections with different upper and lower cross sections, such as transition sections in raw coal hoppers. Lofting generates surfaces by defining the upper and lower cylinder wall outlines and guide paths.

[0034] For the transition section of the raw coal hopper, the shape and size of its top and bottom cross-sections often differ, making simple stretching or rotation impossible to generate. The lofting algorithm generates a smooth transition surface by defining the upper and lower cylinder wall contour lines separately, and then defining the guide path connecting the upper and lower contours. This generation method is consistent with the expression format of the design data; designers only need to provide the contour lines and guide lines of the upper and lower cross-sections to complete the modeling, without the need for complex surface fitting calculations. This algorithm, used in conjunction with other shell generation algorithms such as stretching, rotation, sweeping, and planar generation, can cover the modeling needs of all sections of the raw coal hopper.

[0035] After completing the 3D shell model, it is necessary to create the setup positions for key components such as supports and stiffeners to facilitate subsequent constraint definition and load application. The setup positions for supports and stiffeners are created by dividing the shell model using a reference plane.

[0036] Supports and stiffeners are crucial components in the original coal hopper structure, and their placement directly affects the structure's load-bearing performance. By dividing the shell model using a pre-established reference plane, clear boundary lines can be formed on the shell surface; these boundary lines indicate the installation locations of the supports and stiffeners. The division operation is based on the existing reference plane, requiring no additional reference geometry creation and maintaining consistency with the reference plane system in the preceding modeling steps. After determining the placement locations through division, constraints can be applied or components defined at these locations in subsequent steps to ensure that the load transfer path in the model matches the actual structure.

[0037] Before generating the .inp model file, all pre-modeling processing work, excluding nonlinear loads, needs to be completed. The modeling steps, excluding the application of nonlinear loads, include: assigning element material and section properties, meshing, creating analysis steps, defining constraints, and applying linear loads; these linear loads include circumferentially distributed loads at the top and bottom edges of the structure.

[0038] Assigning element material and section properties involves assigning the defined steel properties and various component section types to the corresponding shell elements. Meshing discretizes the continuous shell into finite elements, preparing for numerical calculations. Creating an analysis step defines the loading sequence and calculation type. Defining constraints applies boundary conditions at the support locations. Applying linear loads includes circumferential uniformly distributed loads at the top and bottom edges of the structure. The above steps are performed according to the conventional ABAQUS preprocessing sequence, with linear loads taking values ​​based on the "Code for Design of Building Structures" (GB50009-2012) and the "Code for Design of Civil Structures of Power Plants" (DL / T5022-2023). Separating linear loads from subsequent nonlinear loads processed by a dedicated program makes the load application logic clearer and facilitates separate verification of the correctness of the two types of loads.

[0039] The nonlinear load module development program is the core tool for handling nonlinear loads on the cylinder wall in this method. Updating the .inp model file using the nonlinear load module development program includes: acquiring input parameters and verifying their accuracy; reading the .inp model file and generating the element matrix and node matrix of the element set; determining the element tilt type; if the element type is tilted, calculating the normal stress, tangential stress, and vector of each tilted element; if the element type is vertical, calculating the normal stress of each vertical element; inserting the calculation results into a fixed string to generate the .inp statement for applying the nonlinear load; copying the .inp model file, inserting the generated .inp statement into the copied document, and saving it to complete the update of the .inp model file.

[0040] The input parameters include six items: the .inp model file name, the element set name, the element tilt type, the raw coal density, the load partial factor, and the internal friction angle. The values ​​of the raw coal density and the internal friction angle are determined according to Article 5.9.3 of the "Code for Design of Civil Structures of Power Plants" (DL / T5022-2023). Verifying accuracy is crucial to prevent errors in parameter input that could lead to deviations in the calculation results. The element matrix generated after reading the .inp model file records the element number and its four corresponding node numbers; the node matrix records each node number and its spatial coordinates. These two matrices provide a complete data foundation for subsequent stress calculations. Different calculation branches are executed after determining the element tilt type, because tilted cylinder walls bear both normal and tangential stresses, while vertical cylinder walls only bear normal stress. After the calculation is complete, the results are inserted into a fixed string format to generate a load application statement conforming to ABAQUS syntax, and then the .inp model file is updated through copying and inserting operations. In the above process, matrix generation provides data support, type judgment ensures the correct selection of calculation branches, and string generation realizes the connection with ABAQUS syntax. The combination of the three enables the automatic processing of nonlinear loads that originally needed to be applied manually one by one.

[0041] When calculating the normal and tangential stresses on a unit, the calculation methods for inclined and vertical units differ, and each involves different physical parameters.

[0042] After determining the tilt type of the unit, the calculation of the normal and tangential stresses on the unit specifically includes: calculating the normal stress of the tilted unit based on the angle between the calculated unit and the horizontal plane, the lateral pressure coefficient, and the vertical pressure at the calculated section; calculating the tangential stress of the tilted unit based on the vertical pressure at the calculated section, the lateral pressure coefficient, and the angle between the calculated unit and the horizontal plane; and calculating the normal stress of the vertical unit based on the lateral pressure coefficient of the vertical cylinder wall, the density of the coal, and the distance from the top surface of the coal to the calculated section.

[0043] Inclined elements calculate both normal and tangential stresses and their vectors, while vertical elements calculate only the normal stress. This differentiated approach aligns with the actual stress characteristics of the two types of cylinder walls and avoids calculation errors that might result from a uniform approach.

[0044] When performing the analysis step and obtaining the results, different load partial factors are used for the calculation of stress and deformation, and the deformation results need to be checked with reference to relevant standards.

[0045] Performing the analysis step and obtaining the results includes: importing the updated inp model file into the CAE module, or directly calling the ABAQUS solver, performing the elastoplastic analysis step, and obtaining the stress and displacement contour plots of the structural model; when performing stress calculations, the load partial factors are taken according to the ultimate limit state of bearing capacity; when performing deformation calculations, the load partial factors are taken according to the serviceability limit state.

[0046] Perform an elastoplastic analysis step on the updated inp model file and output stress and displacement contour plots. Referring to the *Code for Design of Building Structures* (GB50009-2012) and the *Code for Design of Civil Structures of Power Plants* (DL / T5022-2023), the stress calculation corresponds to the ultimate limit state of bearing capacity, with load partial factors taken as 1.3DL + 1.4LL; the displacement calculation corresponds to the serviceability limit state, with load partial factors taken as 1.0DL + 1.0LL, where DL is the self-weight of the top cover and equipment, and LL is the self-weight of the raw coal. The deformation results are verified according to Article 5.9.14 of the *Code for Design of Civil Structures of Power Plants* (DL / T5022-2023): when the wall panels of a steel coal hopper are reinforced with stiffening ribs, the deflection of the wall panels should not exceed 1 / 150 of the plate span, and the deflection of the stiffening ribs should not exceed 1 / 250 of their span. The above distinction ensures that the correct load partial factors are used for stress calculation and deformation calculation, avoiding structural insecurity or over-design that may result from uniform values.

[0047] After completing the calculations and determining that the results meet the design requirements, it is necessary to output the standard design documents. Outputting the calculation results and forming a complete calculation report includes: importing the component information, load information, constraint conditions, and calculation cloud diagram results from the calculation model into a pre-prepared calculation report template to form a complete calculation report.

[0048] The calculation report is a crucial output document in structural design, primarily containing project overview, design basis, and finite element analysis (FEM) calculations. The FEM calculations include load values, material information, the FEM model, and the calculation results. By pre-creating a calculation report template, component information, load information, constraints, and calculation contour plots from the calculation model can be imported into the template, automatically generating a complete calculation report file. This template-based generation method avoids the repetitive work of manually compiling calculation results and creating calculation reports, while also reducing potential errors during data transcription.

[0049] This invention provides a design method for raw coal hoppers in thermal power plants based on ABAQUS. Compared with existing technologies, it has the advantages of high modeling efficiency, accurate load application, and standardized design process. It achieves parametric modeling and analysis of the raw coal hopper structure, rapid configuration of nonlinear loads under complex working conditions, improves overall design efficiency and computational reliability, and forms a reusable and standardized design process, meeting the needs of engineers for rapid and accurate design of special structures such as raw coal hoppers in thermal power plants.

[0050] The technical solution of the invention will be further described in detail below through embodiments and in conjunction with the accompanying drawings.

[0051] like Figure 1 As shown, a design method for raw coal hoppers in steel structures of thermal power plants based on ABAQUS includes the following steps: Step S1: Establish a database of materials and component sections for the raw coal hopper structural model.

[0052] The main materials are Q235B and Q355B steel. Component cross-section types include angle steel, channel steel, T-beams, and composite stiffeners welded from rectangular steel plates. Commonly used angle steel types include L100×10; channel steel types include [20a, [14a); and T-beam types include TM225×300, TN125×125, etc. The model database composed of the above materials and component cross-sections facilitates parametric selection and replacement during subsequent initial and iterative design processes.

[0053] Step S2: Establish a three-dimensional shell model using the reference plane and line / shell generation algorithm.

[0054] Based on the design data, a reference plane is established at key elevations, such as the top and bottom of the coal hopper, the support height, and the connection between the top and bottom of the transition section. Corresponding cylinder wall contour lines are then created within this plane. Next, a three-dimensional shell model of the original coal hopper is created using a shell generation algorithm. Shell generation algorithms include various forms, such as extrusion, rotation, sweeping, planarization, and lofting. Lofting, in particular, can generate special surfaces by defining the upper and lower cylinder wall contour lines and guide paths, offering advantages for modeling coal hopper structures with complex geometries. Furthermore, after the shell model is created, parametric adjustments to similar models can be achieved by adjusting the elevation of the reference plane and the cylinder wall contour lines within the plane.

[0055] Step S3: Create the location settings for key components such as supports and stiffening ribs.

[0056] The placement of key components such as supports and stiffeners is primarily achieved by rationally dividing the shell model. A common method is to use a reference plane for division, that is, to pre-establish a reference plane and then use it to divide the shell model.

[0057] Step S4: Complete the modeling steps except for applying nonlinear loads, and generate the inp model file (ABAQUS input file).

[0058] The specific modeling steps include: assigning material and section properties to elements, meshing, creating analysis steps, defining constraints, and applying linear loads. Linear loads include circumferentially distributed loads at the top and bottom edges of the structure. The top load is the self-weight of the coal hopper cover, while the bottom load mainly considers the self-weight of the equipment pulled down and the self-weight of the raw coal within the vertical projection of the funnel opening. Referring to the "Code for Design of Building Structures" (GB50009-2012) and the "Code for Design of Civil Structures of Power Plants" (DL / T5022-2023), the basic load combination for stress calculation is 1.3DL + 1.4LL; the basic load combination for displacement calculation is 1.0DL + 1.0LL, where DL is the self-weight of the cover and equipment, and LL is the self-weight of the raw coal.

[0059] Step S5: Activate the nonlinear load module development program and update the inp model file. This program can be used multiple times to comprehensively calculate the normal and tangential stresses on the cylinder wall, generate inp statements for the ABAQUS load module, and update the inp model file.

[0060] Furthermore, such as Figure 2 As shown, step S5 includes: Step S51: Prompt the user to input multiple parameters and verify their accuracy. There are six input parameters: (1) inp model file name; (2) element set name; (3) element tilt type: tilt / vertical element; (4) raw coal density; (5) load partial factor; and (6) internal friction angle. Among them, the element set name is the custom name of the element set to be loaded in the finite element model; the values ​​of raw coal density and internal friction angle are based on Article 5.9.3 of the "Code for Design of Civil Structures of Power Plants" (DL / T5022-2023).

[0061] Step S52: Read the inp model file and generate the unit matrix EL and node matrix NL of the input unit set. The size of the unit matrix EL is... ×5, For the total number of units, its first unit is... i Travelogue , For the first i The unit number, The four nodes corresponding to this unit are numbered; the size of the node matrix NL is... ×4, For the total number of nodes, its th j Travelogue , For the first j The node number, These are the spatial coordinates of the node.

[0062] Step S53: Determine the input element tilt type parameter. If the element type is tilted, proceed to step S541; if the element type is vertical, proceed to step S542.

[0063] Step S541: By obtaining the element and corresponding node coordinates, iteratively calculate the normal stress, tangential stress, and vector of each inclined element. The stress calculation formula is as follows.

[0064] Normal stress of inclined cylinder wall The formula for calculating (kPa) is: ; ; ; ; In the formula, To calculate the coefficients, Indicates the lateral pressure coefficient. Indicates the angle of internal friction. Indicates the distance below the top surface of the coal or the center of gravity of the cone. (m) Vertical pressure per unit area (kPa), α represents the angle (°) between the cylinder wall and the horizontal plane. This indicates the density of coal (kN / m³). 3 ), This indicates the distance (m) from the top surface of the coal or the centroid of the cone to the calculated cross section.

[0065] Tangential stress of inclined cylinder wall The formula for calculating (kPa) is: ; The meanings of the letters in the formula are the same as those described above. In addition, the tangential stress vector is obtained by first assuming a unit-length normal vector for the element, and then calculating it using the vertical projection of this normal vector onto the element.

[0066] Step S542: By obtaining the element and corresponding node coordinates, iteratively calculate the normal stress on each vertical element. (Vertical cylinder wall normal stress) The formula for calculating (kPa) is: ; The meanings of the letters in the formula are the same as those described above.

[0067] Step S55: Insert the calculation results into a fixed string to generate an inp statement about the application of nonlinear loads.

[0068] Step S56: Copy the inp model file, insert the inp statements generated in step S55 into the copied document and save it to complete the update of the inp model file.

[0069] Step S6: Perform the analysis step and obtain the results.

[0070] Import the updated .inp model file into the CAE module, or directly call the ABAQUS solver to execute the elastoplastic analysis step to obtain the stress and displacement contour plots of the structural model. Referring to the *Code for Design of Building Structures* (GB50009-2012) and the *Code for Design of Civil Structures of Power Plants* (DL / T5022-2023), the load partial factors for stress and displacement calculations are taken according to the ultimate limit state and serviceability limit state, respectively. The deformation results refer to Article 5.9.14 of the *Code for Design of Civil Structures of Power Plants* (DL / T 5022-2023) regarding the deflection of wall panels and stiffeners: when stiffeners are used to reinforce the wall panels of a steel coal hopper, the deflection of the wall panel should not exceed 1 / 150 of the plate span, and the deflection of the stiffener should not exceed 1 / 250 of its span.

[0071] Step S7: Determine the calculation result.

[0072] If the result meets the design requirements, proceed to step S9.

[0073] Step S8: Structural design iteration.

[0074] If the calculation results do not meet the design requirements, repeat steps S2 to S7 to perform iterative design. Iterative design can utilize parametric methods, such as adjusting the cylinder wall thickness, the position of stiffening ribs, and the cross-sectional type, until the calculation results meet the design requirements.

[0075] Step S9: Output the calculation results to form a complete calculation report.

[0076] Calculation reports can be generated using pre-prepared templates. The main contents of a calculation report include: project overview, design basis, and finite element analysis. The finite element analysis includes load values, material information, the finite element model, and the calculation results. By importing important information such as components, loads, and constraints from the calculation model, along with the calculation contour plot results, a complete and accurate calculation report file can be quickly generated.

[0077] Advantages of this method compared to existing technologies: 1. A highly efficient modeling scheme based on ABAQUS reference plane and line / shell generation algorithms provides a high-precision and high-efficiency solution for modeling complex raw coal hoppers. This scheme transforms the complex spatial node positioning problem in traditional methods into an intuitive key plane design problem, simplifying the model positioning process and better aligning with the original expression of design data. The line / shell generation algorithm has the ability to construct a three-dimensional shell from the cross-sectional contour along a guiding path, providing efficient technical support for surface modeling of complex raw coal hoppers.

[0078] 2. The nonlinear load module development program of this invention transforms the traditional manual and fragmented load application operations into a programmed and parameterized module management process. Through its built-in load modes and automatic analysis algorithms, the program significantly simplifies the definition and application of loads under complex working conditions, avoiding errors and omissions that easily occur when manually selecting nodes and inputting loads, fundamentally improving the accuracy and efficiency of load processing for large models.

[0079] 3. The design method proposed in this invention integrates two main parts: an efficient modeling scheme based on ABAQUS and a nonlinear load module development program. Through parametric means, it systematically simplifies the repetitive work in iterative design and the cumbersome process of arranging nonlinear loads, forming an efficient and accurate design method.

[0080] 4. This invention, through a parameterized and process-oriented design method, enables designers who lack design experience and spatial calculation capabilities to handle the design and calculation of special structures such as raw coal hoppers, and has significant advantages such as low threshold, ease of operation, and easy promotion.

[0081] While the specific embodiments of the present invention have been described above, they are not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art without creative effort based on the technical solutions of the present invention are still within the scope of protection of the present invention.

Claims

1. A design method for raw coal hoppers in steel structures of thermal power plants based on ABAQUS, characterized in that, Includes the following steps: Establish a database of materials and component cross-sections for the raw coal hopper structural model; A three-dimensional shell model is established using a reference plane and line / shell generation algorithm. Create the settings for supports and stiffening ribs; Complete the modeling steps except for applying nonlinear loads, and generate the inp model file; Enable the nonlinear load module development program and update the inp model file; Perform the analysis step and obtain the results; Judge the calculation results. When the results meet the design requirements, output the calculation results and generate a complete calculation report. If the results do not meet the design requirements, repeat the aforementioned steps to iterate the structural design until the calculation results meet the design requirements, then output the calculation results and form a complete calculation report.

2. The design method for raw coal hoppers in steel structures of thermal power plants based on ABAQUS as described in claim 1, characterized in that, The establishment of the material and component section database for the raw coal hopper structural model includes: defining material properties and component section types. The materials are Q235B and Q355B steel, and the component section types include angle steel, channel steel, T-beams, and composite stiffening ribs welded from rectangular steel plates.

3. The design method for raw coal hoppers in steel structures of thermal power plants based on ABAQUS as described in claim 1, characterized in that, The process of establishing a three-dimensional shell model using a reference plane and a shell generation algorithm includes: establishing a reference plane at key elevations based on design data, creating corresponding cylinder wall contour lines within the plane, and using a shell generation algorithm to create a three-dimensional shell model from the cylinder wall contour lines; the shell generation algorithm includes extrusion, rotation, sweeping, planarization, and lofting.

4. The design method for raw coal hoppers in steel structures of thermal power plants based on ABAQUS as described in claim 3, characterized in that, Lofting generates a surface by defining the outlines of the upper and lower cylinder walls and the guide path.

5. The design method for raw coal hoppers in steel structures of thermal power plants based on ABAQUS as described in claim 1, characterized in that, The locations for supports and stiffening ribs are created by dividing the shell model using a reference plane.

6. The design method for raw coal hoppers in steel structures of thermal power plants based on ABAQUS as described in claim 1, characterized in that, The modeling steps, excluding the application of nonlinear loads, include: assigning material and section properties to the elements, meshing, creating analysis steps, defining constraints, and applying linear loads; the linear loads include circumferentially distributed loads at the top and bottom edges of the structure.

7. The design method for raw coal hoppers in steel structures of thermal power plants based on ABAQUS as described in claim 1, characterized in that, Enabling the development process for nonlinear load modules and updating the .inp model file includes: Obtain input parameters and verify their accuracy; Read the inp model file and generate the cell matrix and node matrix of the cell set; Determine the element tilt type. When the element type is tilted, calculate the normal stress, tangential stress, and vector of each tilted element. When the element type is vertical, calculate the normal stress of each vertical element. Insert the calculation results into a fixed string to generate an inp statement for applying nonlinear loads; Copy the inp model file, insert the generated inp statements into the copied document, and save it to complete the update of the inp model file.

8. The design method for raw coal hoppers in steel structures of thermal power plants based on ABAQUS as described in claim 7, characterized in that, After determining the tilt type of the unit, the calculation of the normal and tangential stresses on the unit specifically includes: calculating the normal stress of the tilted unit based on the angle between the calculated unit and the horizontal plane, the lateral pressure coefficient, and the vertical pressure at the calculated section; calculating the tangential stress of the tilted unit based on the vertical pressure at the calculated section, the lateral pressure coefficient, and the angle between the calculated unit and the horizontal plane; and calculating the normal stress of the vertical unit based on the lateral pressure coefficient of the vertical cylinder wall, the density of the coal, and the distance from the top surface of the coal to the calculated section.

9. The design method for raw coal hoppers in steel structures of thermal power plants based on ABAQUS as described in claim 1, characterized in that, Performing the analysis step and obtaining the results includes: importing the updated inp model file into the CAE module, or directly calling the ABAQUS solver, performing the elastoplastic analysis step, and obtaining the stress and displacement contour plots of the structural model; when performing stress calculations, the load partial factors are taken according to the ultimate limit state of bearing capacity; when performing deformation calculations, the load partial factors are taken according to the serviceability limit state.

10. The design method for raw coal hoppers in steel structures of thermal power plants based on ABAQUS as described in claim 1, characterized in that, Outputting calculation results and generating a complete calculation report includes importing component information, load information, constraint conditions, and calculation cloud diagram results from the calculation model into a pre-prepared calculation report template to generate a complete calculation report.

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