Application of the hottest virtual test system in

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Research on the application of virtual test system in metal bulk forming introduction in recent years, although some advanced cad/cae/cam technologies have been adopted in the field of plastic forming, CAD technology and CAE technology remain relatively independent and mutually closed, which makes the information of die CAD system and die CAE system unable to be shared; In terms of overall management, the whole operation process is serial rather than parallel, so it can not meet the requirements of flexibility, quickness, low cost and high quality in modern manufacturing industry; Market demand, mold design, manufacturing and product processing are divided independently, and there is no overall concept. There is often a lack of feasibility and economic benefit evaluation of projects, and we cannot actively pay attention to the demand dynamics of the global market; These direct consequences are the waste of a lot of repeated labor and resources (including human resources and material resources)

realize the cax/pdm integration of metal precision bulk forming, so that users can realize collaborative design and Analysis on the internet/intranet, and construct a virtual test system with a three-dimensional CAD system; At the same time, the performance of the test system is analyzed and evaluated through analysis and simulation, and the test system constructed by the CAD system is modified according to the evaluation results, and the cycle continues until it meets the requirements. Through metal plastic simulation software (such as form, super, MARC), the processing process is simulated, and the influence of force and energy parameters on forming is analyzed. In this process, the PDM system will strictly monitor and manage the process design process and design data (including engineering version) of the test system. When the test is completed, Integrated technology will realize the exchange of input and output information of each system, achieve the sharing of information and resources, and avoid unnecessary duplication

2 virtual test system model of metal bulk forming

this system mainly realizes the integrated system of cad/cae/capp, motion and dynamics, management and machining simulation of metal bulk forming, and aims to establish an integrated virtual test system of metal precision bulk forming. The whole test system consists of test plan, virtual equipment, virtual mold, virtual formed parts and analysis tools. Including process rehearsal; Data acquisition and processing; Data visualization of the test (in the form of generated curves, cloud charts, reports, HTML and VRML); Simulation and analysis of machining process; Optimization of test parameters and mold parameters; The supporting tool for the certification, confirmation and qualification of test results. Figure 1 shows the functional model of the virtual test system for metal bulk forming

through the Internet, the enterprise submits the test requirements or design requirements of the product. The experimenter analyzes the requirements and carries out the conceptual design of the volume forming parts at the same time. If the requirements are met, the virtual prototype and the design of the die and mold base will be started respectively. In the virtual prototype design, the relevant parameters of the forming equipment will be obtained from the forging knowledge base according to the analysis results of the forming process, And make analysis and adjustment according to actual needs. Volume forming equipment has great similarity, so it can be divided into modules, establish a standard parts library for use, and carry out virtual assembly, add constraints, increase loads, power sources. At the same time, it can be combined with MATLAB to carry out electromechanical hydraulic integration simulation as needed, and visualize the test results, and then send them to an expert certification tool for certification. After repeated testing, it is completed. The other is the process of mold design and processing analysis. First of all, the volume forming process is specified according to the needs of customers. These processes will guide the prototype, mold, mold base, plastic forming simulation and other work, so it is very critical. Then, modularization division is carried out according to the forming type, and standardized clustering is carried out according to the parameters of each processing process, so as to improve the efficiency of finite element analysis, establish the neural network structure corresponding to the forming, optimize the main parameters of the die, generate the required visual results, and submit it to the expert certification tool for certification

3 research content and implementation method

3.1 modularization of volume forming virtual prototype (forming equipment geometric model library) to realize packaging and calling

classify and divide equipment types and part features according to the types of volume forming to realize modularization. Carry out secondary development of existing CAD software (SolidWorks, API of SolidEdge, which is developed using VB, VC and Delphi; pro/develop, pro/toolkit, JLINK of pro/engineer, which can be developed using c/c++, Java technology, etc.), establish forming equipment types, component series, standard parts database, module package forming equipment, and establish parametric interface to call virtual prototype software. Using the good interface between CAD software and virtual prototype software (pro/engineer and Adams, DDM of Solidworks, adams/exchange and working model are fully integrated in the menus of MDT, SolidWorks and SolidEdge), seamless integration is achieved

3.2 parameterization of volume forming test pieces and mold and mold base library

in the process of virtual test, in addition to realizing mold and optimization design, a large number of parameters of the mold need to be adjusted and tested, so the parameterized design of mold cavity and test pieces is a basic step. For example, in the virtual test of cross wedge rolling, it can be based on the initial size of parts, end face shrinkage, wedge angle, widening angle The rolling length is designed parametrically, the interactive interface is compiled, and the die is automatically generated according to the input parameters. Most of the volume formed parts have regular shapes (such as gears, splines, etc.). Parameterization will greatly improve the efficiency of the test. Use the development software (such as vb/vc++, Java, python) on the platform to call the API function or class library of CAD software, and realize its purpose according to the needs of volume forming

3.3 construction of knowledge base framework of volume forming process

the determination of volume forming process is the basis of volume forming design, which determines the quantity and shape of tooling in the process of volume forming. Volume forming generally includes the forming steps of the workpiece, whether blank making is required, the distribution of materials during blank making, the tooling required for each step, the tonnage of equipment required, and the blanking specification; The parting surface of the forging die, the layout of the die cavity, the wall thickness of the die cavity, the structure and size of the flash groove, and whether the ejector rod is needed should be considered. The required data can be obtained from the volume forming process knowledge base, such as the performance data of forging materials, virtual equipment test data, friction and lubrication, forging design, process design and die design process required design criteria, design standards and design parameters

3.4 virtual test analysis, design neural network, optimize mold parameters

using finite element analysis and neural network, the geometry of the mold can be effectively predicted, so that the setting range of the mold insulation layer should be the outer wall of the inner space or the inner surface of the partition wall with the public part; It is really necessary to optimize the architectural design effect of the external wall external insulation system, and at the same time, it can prevent the defects in the metal volume forming. The parameters optimized by neural network are used to predict the filling of the cavity of optional forgings, and the geometry of the die can also be predicted by reverse simulation with the geometry of the final product

at present, the international metal forming finite element commercialization software, such as deform, Antares, DYNAFORM, marc/superform, has been applied to production practice, but the post-processing interface is not friendly, and it is difficult to integrate into the virtual test system, so it is necessary to carry out visual research on finite element post-processing, use visual c++ and other development tools, with the help of OpenGL graphical interface, to realize lattice deformation diagram Isoline (stress, strain, strain rate, velocity), color cloud diagram, velocity vector diagram, pressure and stroke curve diagram

at the same time, expert evaluation and confirmation tools are embedded in the visual platform to evaluate the molds and processes used in the test simulation

3.5 networking research

remote collaborative design, networking data sharing, annotation; Establish a virtual test platform to realize the data interface and system integration between modules. Networking is the key technology of computer-aided design at present, and it is also the urgent need of virtual experiment of volume forming. The current PDM basically realizes the network function, and uses its unique functions to realize the management of shared part database and product database, and realize the archiving of equipment performance analysis data and product information, processing simulation animation demonstration, part forming animation demonstration, test report browsing and other functions. Figure 2 shows the virtual test collaboration model of metal bulk forming

4 key technologies

the virtual test system for metal bulk forming will be widely used. The system platform includes many common technical platforms, including CAD, virtual prototype, control system, optimization, network technology, finite element, database, knowledge base, graphics and other technologies. The following are several related key technologies:

1) establish a virtual test model with physical properties

2) the construction of the knowledge base framework of volume forming process (material performance data, virtual equipment test data, friction, forging design, forming process design and mold design process required design criteria, design standards and design parameters)

3) dynamic simulation of volume forming, analysis and evaluation of defect causes

4) visualization technology of finite element post-processing based on image

5) the total ordinary stretching stroke of the part database is 100 ⑵ 00mm, which is enough to enjoy technology, permission setting and task allocation

6) architecture and data interface technology of collaborative product development environment

7) research on standardized clustering of metal bulk forming

8) applied research of nerve collaterals in metal volume forming

5 application examples and conclusions

this paper focuses on the study of the virtual system of metal bulk forming. In order to more vividly express the author's idea, the author designed a simple example - the virtual experiment of cross wedge rolling. Metal bulk forming includes rolling, extrusion, drawing, free forging, open die forging, closed die forging and deep drawing. Cross wedge rolling is a new forming process of shaft parts. It has the advantages of high precision, high efficiency and material saving when processing stepped shaft parts. It is widely used in the production of shaft parts such as automobiles, tractors and motorcycles. At the same time, because of the characteristics of cross wedge rolling die design difficulties, cumbersome process, imprecise forming geometric analysis, expensive development of cross wedge rolling mill, it is in line with the application scope of virtual test system. The simulation prototype designed by using virtual prototype technology and the virtual scene of cross wedge rolling test can realistically realize the whole process of the test. By changing the design parameters and temperature parameters of cross wedge rolling die interactively, the design scheme can be verified, so as to shorten the design cycle, reduce the development cost and improve the product quality. At the same time, the whole process of machining is simulated through finite element simulation, which lays a foundation for the further study of cross wedge rolling

from the analysis of the basic process of virtual test, we know that the design of cross wedge rolling equipment, mold design and cross wedge rolling test are carried out synchronously. Among them, the virtual prototype of cross wedge rolling needs to go through the steps of conceptual design, namely, preliminary design, virtual prototype assembly, recommended parts library and parts library, and electromechanical integration simulation of virtual equipment system of cross wedge rolling. At the same time, a knowledge base of cross wedge rolling process is established to guide the whole virtual test

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