Structural feature parametric modeling method for typical parts of aero-engine

Abstract

The invention belongs to the field of intelligent manufacturing of aero-engines, and provides a parametric modeling method for structural characteristics of typical parts of an aero-engine. According to the method, efficient precision machining of the aero-engine compressor blade is achieved through an intelligent system of parametric modeling, feature self-recognition and rapid programming. The specific implementation process comprises the steps that a three-dimensional model is generated through a parametric modeling module on the basis of a tenon structure parameter set and a blade body profile geometric feature parameter set input by a user; secondly, a feature recognition module is used for conducting multi-level machining feature decomposition on the three-dimensional model, and key machining features such as a tenon and a blade body profile are precisely recognized through a geometric topology analysis and depth feature learning fusion algorithm; on the basis, intelligent matching and optimization of the machining technology are achieved for the recognized machining features through a rapid programming module, the machining program is optimized through physical simulation, and finally the machining program applied to the production field is generated.

Description

Technical Field

[0001] This invention belongs to the field of intelligent aeroengine manufacturing technology, specifically a method and design and manufacturing program for efficient and precise machining of aeroengine blades based on the coordinated optimization of parametric modeling, feature recognition, and rapid programming strategies. By constructing a multi-strategy collaborative blade geometry-process integrated manufacturing system, rapid and high-quality machining of complex curved surface components is achieved. Background Art

[0002] Aeroengine blades are typically difficult-to-machine parts in the aeroengine manufacturing industry. Their blade profiles and tenon teeth are characterized by complex geometric structures and poor machining processability. Traditional CNC machining methods, due to their limited versatility, suffer from low programming efficiency, frequent repetitive processes, poor machining quality consistency, and excessive reliance on manual experience, making efficient and high-precision blade manufacturing difficult.

[0003] In the field of digital manufacturing, although the application of MBD technology has promoted the digital integration of design and manufacturing, there are still significant technical bottlenecks, including: insufficient model conversion efficiency, low maturity of key algorithms such as 3D process model generation and machining path planning, resulting in the conversion efficiency of design models to manufacturing links being unable to meet the requirements; complex feature analysis is difficult, and complex structures such as hollow cooling channels and special-shaped surfaces lead to huge amounts of model data. Multi-level feature analysis is prone to misjudgment, affecting the accuracy of cross-departmental collaboration and data security.

[0004] Existing technologies, such as patent CN202310836928.2 (Method and System for Self-Programming Parametric Modeling of Ventilator Microturbine Blades), propose a parametric modeling solution but fail to address process challenges such as intelligent recognition of machining features and automated CNC programming, making it difficult to directly apply to complex blade machining scenarios. Patent CN 202211415122.8 (Wizard-Based Rapid Programming Method for Aircraft Engine Casing Parts) only provides a rapid programming solution for aircraft engine casing parts, failing to address issues such as lengthy initial modeling time and over-reliance on manual experience.

[0005] To address the above problems, the present invention proposes a multi-strategy collaborative rapid manufacturing method and design and manufacturing program for aircraft engine compressor blades. By integrating parametric modeling, multimodal feature recognition and adaptive programming technology, it aims to achieve intelligent manufacturing of compressor blades. Summary of the Invention

[0006] The purpose of this application is to provide a parametric modeling method for the structural features of typical aircraft engine parts, which realizes efficient and high-quality blade processing through parametric modeling of typical structural features of aircraft engine compressor blades, automatic identification and extraction of processing features, and rapid CNC programming based on processing features.

[0007] In order to achieve the above objectives, this application provides the following solutions:

[0008] First aspect: The present application provides a method for rapidly generating geometric feature models of aero-engine compressor blades based on parametric modeling, which is characterized in that: for typical structural features of blades (such as blade profile, tenon, etc.), based on the geometric parameters input by the user, a model is constructed through a parametric modeling module in the design and manufacturing program. Taking the blade profile as an example, cubic NURBS surface modeling technology is adopted to construct the blade profile through closed spline curves, and a three-dimensional blade model is generated based on the "through curve group" method in free surface modeling. On this basis, process constraints are integrated, cutting parameters, tool geometry information and process requirements are input through the human-computer interaction interface, and mechanical, thermodynamic and dynamic characteristics simulation analysis is carried out simultaneously, and finally a composite feature model that meets the data exchange standard is generated. The model contains both geometric topology information and processing technology attributes, providing a standardized data basis for subsequent feature recognition and CNC programming.

[0009] Second, the present application provides a method for automatically identifying and extracting machining features based on a three-dimensional model of a typical blade structure. Based on the three-dimensional model of the typical blade structure obtained through parametric modeling, a feature recognition module within the blade design and manufacturing program is utilized. This module employs a rule-based feature recognition method to relatively quickly identify key machining features. Specifically, the method includes: first, obtaining the TAG values ​​of all faces and edges of the three-dimensional model of the typical blade structure. Second, based on the structural characteristics of the aircraft engine compressor blade, the machining features of the aircraft engine compressor blade are divided into a blade body feature group and a tenon feature group. Based on the machining and structural characteristics of the compressor blade, corresponding recognition rules and methods are developed and converted into a feature recognition algorithm. The identification of machining features such as the blade body profile, root fillet, and lip plate curved surface of the compressor blade is then completed by determining the type of the seed surface. Finally, based on the established recognition rules, the tenon end face, side face, chamfer, and bottom face are searched and identified, and the geometric information of the features is extracted. In order to solve the problem of tool path interference in CNC programming, a feature recognition technology considering auxiliary surfaces was proposed, and color values ​​were also used as one of the recognition rules, providing key support for the rapid compilation of CNC programs in the next aspect.

[0010] The third aspect: The present application provides a method for rapidly generating a processing program for the production site based on the typical structural processing features of the identified blades. Specifically, it includes: decomposing the compressor blades into independent processing features through the blade feature recognition module, combining the rapid programming module in the blade design and manufacturing processing program to realize the automatic selection of the driving surface and the dynamic call of the processing template. The rapid programming module pre-builds a standardized processing template containing the creation program, processing method and fixed parameters. When programming a new blade, it is only necessary to import the template and supplement the variable data such as the tool path and cutting parameters. The CNC program compilation is quickly completed through the feature-driven tool path automatic generation technology, and the physical simulation verification mechanism is simultaneously integrated to optimize the processing path to form a digital process solution suitable for the production site. This method significantly shortens the programming cycle through template reuse and parameterized drive mechanism, improves the reuse rate of process knowledge, and realizes efficient and accurate programming of complex blade features. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following

[0012] The drawings that need to be used are briefly introduced. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0013] Figure 1 Flowchart for parametric modeling of blade profile

[0014] Figure 2 Modeling effect diagram of blade surface

[0015] Figure 3 Flowchart for blade feature recognition

[0016] Figure 4 Schematic diagram of the blade body structure

[0017] Figure 5 Schematic diagram of the tenon structure of the blade

[0018] Figure 6 Flowchart for identifying blade features

[0019] Figure 7 Flowchart for identifying tenon features

[0020] Figure 8 Color assignment diagram for blade processing features

[0021] Figure 9 The result diagram of blade processing feature recognition

[0022] Figure 10 This is the cutting area interface in UG software

[0023] Figure 11 Diagram of the surface area driving method in UG software

[0024] Figure 12 Generate interface diagram for the program

[0025] Figure 13 Tool path diagram

[0026] Figure 14 Overall framework diagram of the integrated modeling system for designing and manufacturing typical blade features

[0027] Figure 15 This is the program login interface diagram

[0028] Figure 16 Modeling interface for blade surface and blade surface model diagram

[0029] Figure 17 Feature recognition interface diagram

[0030] Figure 18 Identification effect diagram of the blade body, tenon and auxiliary surface

[0031] Figure 19 Blade blank drawing

[0032] Figure 20 Programming interface and tool path diagram for blade processing

[0033] Figure 21 Programming interface and tool path diagram for tenon processing DETAILED DESCRIPTION

[0034] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0035] The specific application process of this system is as follows: based on the typical feature parameters of the blade surface, tenon, etc. input by the user, the model is constructed through the parametric modeling module in the design and manufacturing program, and the geometric shape is defined by dimensional constraints, topological constraints and engineering performance constraints. The processing technology attributes are integrated to generate a composite feature model that meets the data exchange standard; based on this three-dimensional model, the feature recognition module is called to quickly identify key processing features such as the blade surface and tenon through a rule-driven algorithm, and potential interference is avoided by combining auxiliary surface recognition and color marking technology; finally, the process intelligent matching of the identified features is carried out with the help of the rapid programming module, the cutting parameters and tool path are optimized based on the genetic algorithm, the program reliability is verified through VERICUT multi-physics field simulation, and high-precision CNC code that can be directly applied to five-axis machine tools is output.

[0036] The present invention is described below in conjunction with specific embodiments:

[0037] Step 1: For the parametric modeling module in the integrated design and manufacturing of aircraft engine compressor blades, taking the blade surface as an example, the present invention uses bicubic NURBS surfaces to model the blade surface. The NURBS surface is defined as follows:

[0038] A NURBS surface of degree p in the u direction and q in the v direction is a two-variable piecewise rational vector-valued function of the following form:

[0039]

[0040] where {P i，j} forms a control grid with two directions, {w i,j} is the weight factor, {N i,p (u)} and {N j,q (v)} are the non-uniform rational B-spline basis functions defined on the knot vectors u and v, respectively.

[0041] The process of parameterized modeling of blade surface geometry is as follows: Figure 1 First, obtain the data file, which contains key information such as blade profile, thickness, twist angle, etc. Based on this data, create data points, and then create cross-sectional curves and perform smoothing. Figure 2 (a); Finally, the blade surface is generated by the "through curve group" command in the UG software. The blade surface model is as follows Figure 2 (b) The key UFUN functions involved in blade surface modeling in UG software are shown in Table 1.

[0042] Table 1 Key UFUN function table

[0043]

[0044] Step 2: For the feature recognition module in the design and manufacturing program of the aero-engine compressor blade, the three-dimensional modeling software used in the embodiment is NX12.0, and the method flowchart for obtaining the TAG values of all faces and edges of the three-dimensional entity model according to the development interface provided by the NX software is shown in FIG. 3. The specific operation of writing a secondary development function to obtain the TAG values of all faces and edges of the blade model is as follows: first, the GetProperties()->GetTaggedObjectVector(“”) function provided by the NX software is called to obtain the TAG values of the aero-engine compressor blade NX entity model, then the function UF_MODL_ask_body_faces() is called to obtain the TAG value chain table of all seed faces of the model, and the TAG value of each seed face is obtained by loop traversal. After the traversal is completed, the function UF_MODL_ask_face_edges() is called to obtain the TAG value chain table of all edges of each seed face, and the TAG value of all edges of each seed face is obtained by loop traversal.

[0045] According to the processing features and structural characteristics of the compressor blade, corresponding recognition rules and recognition methods are formulated, and they are converted into feature recognition algorithm programs; for example, Figure 4 the blade body structure schematic diagram, Figure 5 the tenon structure schematic diagram of the blade. The structural characteristics of the compressor blade are as follows:

[0046] 1) The blade body feature is composed of a blade body surface 1, a blade root fillet 2, and a rim plate curved surface 3. The blade body surface 1 is adjacent to the blade root fillet 2, and the blade root fillet 2 is adjacent to the rim plate curved surface 3; the blade body surface and the rim plate curved surface are both parameter surfaces, and the number of each in the blade is 1. The rim plate curved surface has more edges, and the blade body surface has fewer edges. The blade root fillet is a fillet curved surface.

[0047] 2) The tenon feature is composed of a tenon end face 6, a tenon side face 4, a tenon reverse bevel face 5, and a tenon bottom face 7. The above-mentioned four types of features are all planes, wherein the rim plate face and the tenon side face are adjacent to the rim plate curved surface feature of the blade body feature group, the tenon end face has more edges, and the tenon side face has fewer edges. The tenon reverse bevel face is adjacent to the tenon end face and the tenon side face, and the tenon bottom face is adjacent to the tenon end face and the tenon reverse bevel face.

[0048] for example, Figure 3 the aero-engine compressor blade processing feature recognition method flowchart, Figure 6 the blade body feature recognition flowchart, and Figure 7 the tenon feature recognition flowchart,

[0049] The recognition rule formulation process is as follows:

[0050] 1) Loop through and determine the type of each seed surface of the blade and the number of edges contained in the seed surface, and stipulate that when the type of the seed surface is a parametric surface or a fillet surface, these seed surfaces are collected and stored in the blade feature group;

[0051] 2) Loop through and determine whether all adjacent surfaces of the fillet surface are parametric surfaces. If all adjacent surfaces are parametric surfaces, define the seed surface as the leaf root fillet feature;

[0052] 3) Loop through and determine the number of edges of the parametric surface, define the parametric surface with more edges as the edge plate surface feature, and the parametric surface with fewer edges as the blade surface feature;

[0053] 4) Loop through and determine the type of each seed surface of the blade, and stipulate that when the type of the seed surface is a plane, these seed surfaces are collected and stored in the tenon feature group;

[0054] 5) Loop through the number of included edges of the seed face in the tenon feature group. When the number of included edges of the seed face is defined as 6, the plane is the tenon end face. Loop through the adjacent faces of the seed face in the tenon feature group. Define the plane with 4 edges and an adjacent edge plate surface as the tenon side face; define the plane with 4 edges and an adjacent tenon side face as the tenon chamfered face; and define the plane with 4 edges and an adjacent tenon chamfered face as the tenon bottom face.

[0055] After the aero-engine compressor blades are identified based on the identification rules, new color values ​​are assigned to each feature of the blades. The color assignment of the blade processing features obtained in this embodiment is as follows: Figure 8 shown.

[0056] After the aero-engine compressor blades are identified based on the identification rules, the blade processing feature recognition results obtained in this embodiment are as follows: Figure 9 shown.

[0057] Step 3: For the integrated rapid programming module of aero-engine compressor blade design and manufacturing, the present invention realizes blade processing optimization by constructing a process-driven intelligent programming system. The specific implementation process is as follows: based on the process analysis of the typical structural characteristics of the compressor blade (covering machine tool selection, processing strategy formulation, tool parameter configuration and cooling and lubrication scheme), preset modular processing templates and solidify the core process parameters; by extracting the TAG value of the key features in the blade three-dimensional model, establish the mapping relationship between feature identification and processing strategy, and embed the TAG value into the processing template to realize the accurate matching of feature and process. Add the surface extracted by feature recognition to Figure 10 Use "Select Object" in to match the cutting area.

[0058] In secondary development, the function for matching features to "selected objects" is as follows:

[0059] UF_CAMGEOM_append_items(); / / Set the geometry into the cutting area of ​​the operation

[0060] This function is a built-in function of UG / Open API. By calling this function, the feature-recognized surface can be added to the cutting area of ​​the processing template, thereby realizing the generation of the program.

[0061] At the same time, in CNC machining programming, the driving surface is used to guide the generation of tool paths. The present invention adds feature recognition and extracted surface features to Figure 11 In the "Specify Drive Geometry" in the tool path, the matching drive surface is realized, thereby ensuring the consistency of the tool path with the design intent. In the secondary development, the key function code is as follows:

[0062] NXOpen::Face*face1(dynamic_cast<NXOpen::Face*> (NXOpen::NXObjectManager::Get());

[0063] surfaceDriveGeometrySet1->SetSurface(*); / / Drive geometry setting

[0064] The core of the programming process lies in the digital integration of the process chain: Based on the multi-view system of the process navigator, standardized work steps (including operation naming, tool binding, and cutting parameter loading) are automatically generated through preset machining templates, and a hierarchical architecture is used to reconstruct the machining sequence topology. Visual toolpath models are generated through parameterized drive, and multi-physics coupling simulation (cutting force, thermal, and vibration analysis) is performed using VERICUT to verify the program's completeness in terms of kinematic constraints and process compliance. The resulting NC code is verified through actual machining on a five-axis machine tool, achieving technical indicators of a blade profile error of ≤0.03mm and a 30% increase in single-piece machining efficiency, forming a closed-loop quality control system from process design to machining execution.

[0065] The key functions in the above steps are shown in Table 2 below. Figure 12 As shown. The tool path is as follows Figure 13 shown.

[0066] Table 2 Key function table

[0067]

[0068] Step 4: Integrated modeling system for design and manufacturing of typical features of aero-engine blades Figure 15The blade design and manufacturing program described in the patent of this invention utilizes C++ computer programming language and UG secondary development technology, takes UG / CAD / CAM module as the development platform, and develops a collaborative architecture system that integrates parametric modeling module, feature recognition module and rapid programming module.

[0069] In the blade parametric modeling, call the blade surface modeling dialog box, such as Figure 16 (a) As shown. Click "Import cross-section data points", "Generate spline curve", "Smooth spline curve" and "Generate blade surface" in sequence to generate the blade surface solid model. The blade surface modeling interface is as follows Figure 16 As shown in (b), this module can quickly generate the blade body surface in just 10 seconds.

[0070] In the feature recognition module, call the feature recognition dialog box, select the blade entity, click "Start Recognition Features", and the recognized features will be displayed in the list, such as Figure 17 To facilitate the distinction of features, different features are assigned different color values ​​in the code. Figure 18 As shown in (a), the recognition results of the tenon part are as follows Figure 18 As shown in (b), the auxiliary surface recognition results are as follows Figure 18 (c) shown.

[0071] In this embodiment, before the NC program is quickly compiled, the blade blank is first set, such as Figure 19 Shown in the cyan part.

[0072] After completing the blade feature recognition, check the processing features in the list and select the blade processing template, such as Figure 20 As shown in (a), click the "Generate Processing Path" button to generate the NC tool path, as shown in Figure 20 (b) As shown. The tenon processing template is processed as follows Figure 21 As shown in (a), the tool path is Figure 21 (b) This module can generate the tool path in just 2 minutes.

[0073] The system's post-processing unit utilizes a dual-core architecture combining a machine tool instruction mapping model and a process optimization algorithm. This layered processing mechanism transforms geometric drive paths into executable NC code. The first stage loads the 3D model and planned tool paths; the second stage configures the machine tool's kinematic parameters and process constraints; and the third stage invokes a parametric post-processor for device adaptation and precision control. Finally, the system outputs a standardized NC program that has undergone code verification and process compliance review. This program seamlessly integrates data flows between modules, achieving digital integration of the entire process, from geometric modeling to NC machining.

Claims

1. The method for parameterizing the structural characteristics of typical aircraft engine parts is characterized by: Parametric modeling strategy: Based on the parameters of typical geometric features of aircraft engine compressor blades input by the user, such as blade surface, tenon, etc., parametric modeling is performed using the parametric modeling module in the design and manufacturing process program. Constraints are used to define and modify the geometric model. The established geometric model includes not only geometric information, but also information such as processing technology, forming a geometric feature model that conforms to data exchange specifications. Feature recognition strategy: Based on the three-dimensional model of the typical structural features of the blade obtained by parametric modeling, the feature recognition module in the blade design and manufacturing process is used. This module uses a rule-based feature recognition method to quickly identify key processing features. Rapid programming strategy: Based on the identified processing features of the typical blade structure, the NC program rapid compilation module in the blade design and manufacturing program is called to intelligently match and optimize the processing technology for the identified processing features. The processing program is improved and optimized through existing physical simulation, and finally a processing program is generated for application in the production site.

2. The method for parameterized modeling of structural characteristics of typical aircraft engine parts according to claim 1, characterized in that: Based on the user-entered parameters of typical compressor blade structural features, such as the tenon and blade body surface, the parametric modeling module in the blade design and manufacturing program is called up to input the parameters of the relevant typical structure. The geometric features are modified through dimension-driven and feature discretization and aggregation. On this basis, through the human-computer interaction interface, process conditions such as processing parameters and tool parameters are input to achieve physical simulation calculation modeling and analysis of the force, heat, deformation, and dynamic characteristics of typical structural features. The established geometric model includes not only geometric information but also processing technology information, thereby quickly forming a geometric feature model that meets data exchange specifications.

3. The method for parameterizing the structural characteristics of typical aircraft engine parts according to claim 1 is characterized in that Based on the three-dimensional model of the typical structural features of the blade obtained by parametric modeling, the feature recognition module in the blade design and manufacturing process is used. This module uses a rule-based feature recognition method to quickly identify key processing features. Specifically, it includes: obtaining the TAG value topology information and TAG value of the three-dimensional solid model of the typical structural features of the compressor blade, and further obtaining all the feature faces and corresponding edge numbers of the blade solid model and extracting the attributes of each seed face of the compressor blade model based on this information; based on the defined features that meet the compressor blade processing requirements and their structural characteristics, the corresponding recognition rules and recognition methods are formulated and converted into a feature recognition algorithm program; by judging the type of seed face, the simple processing features such as the compressor blade body surface and blade root fillet of the compressor blade are recognized; the top surface, side surface, end surface and bottom surface of the tenon are searched and recognized through the formulated recognition rules, and the geometric information of the features is extracted; after the feature recognition is completed, different features are given different colors to distinguish them.

4. The method for parameterized modeling of structural characteristics of typical aircraft engine parts according to claim 1, characterized in that: Based on the identified processing features of the typical blade structure, the rapid programming module in the blade design and manufacturing processing program is used to intelligently match and optimize the processing technology of the identified processing features and select the driving surface. The extracted and identified processing features are transferred to the pre-set processing template, and the tool path trajectory is quickly generated to realize the rapid compilation of the NC program of the blade features, effectively reducing the workload of blade NC programming. The processing program is improved and optimized through existing physical simulation, and finally a processing program is generated for application in the production site.

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