CAE (Computer Aided Engineering) refers to computer-aided engineering in engineering design, refers to the use of computer-aided solution to analyze and analyze the structural mechanical properties of complex projects and products, and to optimize structural performance, etc., to organically organize all aspects of engineering (production). The key is to integrate the relevant information so that it is generated and exists in the entire life cycle of the project (product). The CAE software can be used for static structure analysis and dynamic analysis; study linear and nonlinear problems; analyze structure (solid), fluid, electromagnetic, etc.
CAE (Computer Aided Engineering) is a computer-aided solution to the analysis and calculation of mechanical properties such as structural strength, stiffness, buckling stability, dynamic response, heat conduction, three-dimensional multi-body contact, elastoplasticity, etc. of complex projects and products, as well as the optimization design of structural properties. An approximate numerical analysis method. CAE has been applied in engineering from the early 1960s to today. It has experienced more than 50 years of development history, and its theory and algorithms have experienced a process from vigorous development to maturity. It has now become an engineering and product structure analysis (such as aviation , Aerospace, machinery, civil engineering and other fields) are indispensable numerical calculation tools, but also an important means to analyze various problems of continuous mechanics. With the popularization and continuous improvement of computer technology, the functions and calculation accuracy of CAE systems have been greatly improved. Various CAE systems based on product digital modeling have emerged, and have become an important tool for structural analysis and structural optimization. It is also an important part of the computer-aided 4C system (CAD/CAE/CAPP/CAM). The core idea of the CAE system is the discretization of the structure, that is, the actual structure is discretized into a limited number of regular unit combinations. The physical performance of the actual structure can be analyzed by the discrete body to obtain an approximate result that meets the engineering accuracy to replace the actual structure. The analysis can solve many complex problems that need to be solved in actual engineering but cannot be solved by theoretical analysis. The basic process is to decompose the solution area of a complex continuum into finite sub-regions with simple shapes, that is, to simplify a continuum into an equivalent combination composed of a finite number of elements; by discretizing the continuum, the solution The field variable (stress, displacement, pressure, temperature, etc.) of the continuum is simplified to solve the field variable value at the finite element node. The basic equation obtained at this time is a system of algebraic equations, rather than the system of differential equations that originally described the real continuous field variables. After the solution is obtained, an approximate numerical solution is obtained. The degree of approximation depends on the type and number of elements used and the interpolation function for the elements. In response to this situation, color light and dark maps representing stress, temperature, and pressure distribution, we call this process post-processing of CAE.
Computer Aided Engineering (CAE) technology is to organically organize all aspects of engineering (production). The key is to integrate relevant information so that it can be generated and exist in the entire life cycle of engineering (product) . Therefore, the CAE system is a complex system that includes related personnel, technology, management, and organic integration and optimized operation of information flow and logistics.
With the rapid development of computer technology and applications, especially the emergence of large-scale and ultra-large-scale integrated circuits and microcomputers, computer graphics (CG), computer-aided design (CAD) and computer-aided manufacturing (Computer Aided Manufacturing, CAM) and other new technologies have developed very rapidly. CAD and CAM have been widely used in various fields such as electronics, shipbuilding, aviation, aerospace, machinery, construction, and automobiles. They have become the tools with the most production potential, demonstrated bright prospects, and achieved huge economic benefits.
The rapid development of computer technology has also promoted the development of modern enterprise management. With the support and help of management information systems, enterprise management uses information to control the activities of national economic departments or enterprises to make scientific decisions or scheduling, thereby improving management level and benefit. All aspects of the company's production and operation activities, from project establishment, contract signing, design, construction (production), to delivery (delivery), are a continuous process and an organic whole.
Broadly speaking, computer-aided engineering includes many, literally, it can include all aspects of engineering and manufacturing informatization, but the traditional CAE mainly refers to the performance and safety reliability analysis of engineering and products with computers. Simulate its future working status and operating behavior, discover design defects early, and confirm the availability and reliability of future engineering, product functions, and performance. This mainly refers to the CAE software [1].
CAE software can be divided into two categories: software developed for specific types of projects or products for product performance analysis, prediction, and optimization, which is called special CAE software; it can be used for many types of projects and product physics and mechanics The software that analyzes, simulates and predicts, evaluates and optimizes performance to achieve product technology innovation is called general CAE software.
The main body of CAE software is finite element analysis (FEA, Finite Element Analysis) software.
The basic idea of the finite element method is to discretize the structure, to represent complex objects with a finite number of easily analyzed elements, the elements are connected to each other through a limited number of nodes, and then comprehensively solved according to the deformation coordination conditions. Since the number of elements is limited and the number of nodes is also limited, it is called the finite element method. This method is very flexible. As long as the number of units is changed, the accuracy of the solution can be changed, and a solution that is infinitely close to the real situation can be obtained.
The core idea of CAE system based on finite element method is the discretization of structure. According to experience, the time spent in each stage of CAE is: 40% to 45% for model establishment and data input, 50% to 55% for interpretation and evaluation of analysis results, and the real analysis calculation time only accounts for about 5% .
CAD technology is used to establish the geometric and physical models of CAE, and the input of analytical data is completed. This process is generally called the pre-processing of CAE. Similarly, the results of CAE also need to use CAD technology to generate graphical output of the image, such as generating contour maps of displacement maps, stress, temperature, and pressure distribution, and color light and dark maps representing stress, temperature, and pressure distribution. We call this process For: Post-processing of CAE. For different applications, CAE simulation can also be used to simulate the movement and running status of parts, components, devices (complete machines) and even production lines and factories.
Analysis steps
When using CAE software to perform performance analysis and simulation on an engineering or product, it generally goes through the following three processes:
Pre-processing: solid modeling and parametric modeling, Boolean operation of components, automatic division of elements, automatic numbering of nodes and automatic generation of node parameters, direct input of loads and material parameters with formula parameterized import, automatic generation of node loads, limited Meta-model information is automatically generated, etc.
Finite element analysis: finite element library, material library and related algorithms, constraint processing algorithm, finite element system assembly module, static, dynamic, vibration, linear and nonlinear solution library. The physical, mechanical and mathematical characteristics of large-scale general problems are decomposed into several sub-problems, which are completed by different finite element analysis subsystems. Generally, there are the following subsystems: linear static analysis subsystem, dynamic analysis subsystem, vibration mode analysis subsystem, thermal analysis subsystem, etc. [1].
Post-processing: According to the engineering or product model and design requirements, the finite element analysis results are processed and inspected by the user, and provided to the user in a graphical manner to assist the user to determine the rationality of the calculation results and design plan.
Structure and function
The basic structure of CAE software includes the following modules:
Pre-processing module --- for solid modeling and parametric modeling, Boolean operation of components, automatic division of elements, automatic numbering of nodes and automatic generation of node parameters, direct input of loads and material parameters with formula parametric import, automatic load of nodes Generation, automatic generation of finite element model information, etc
Finite element analysis module --- finite element library, material library and related algorithms, constraint processing algorithm, finite element system assembly module, static, dynamic, vibration, linear and nonlinear solution library. The physical, mechanical and mathematical characteristics of large-scale general problems are decomposed into several sub-problems, which are completed by different finite element analysis subsystems. Generally, there are the following subsystems: linear static analysis subsystem, dynamic analysis subsystem, vibration modal analysis subsystem, thermal analysis subsystem, etc.
User interface module, data management system and database, expert system, knowledge base.
CAE software's ability to analyze and simulate engineering and products is mainly determined by the richness and perfection of the cell library and material library. The more cell types the cell library contains, the more complete the variety of material properties included in the material library, and its CAE software The stronger the analysis and simulation ability of the project or product.
The computational efficiency and accuracy of a CAE software is mainly determined by the solution library. The advanced and efficient solution algorithm and the conventional solution algorithm may have a difference of several times, tens of times, or even hundreds of times in the calculation efficiency.
Pre-processing and post-processing are the fastest-growing CAE software components in more than a decade. They are the key software that CAE software meets user needs, professionalizes and localizes general-purpose software, and seamlessly integrates software such as CAD, CAM, CAPP, and PDM. ingredient. They are through the addition of CAD software, such as Pro/Engineer, UG, Solidedge, CATIA, MDT and other software interface data modules to achieve effective CAD/CAE integration.
CAE usually refers to finite element analysis and mechanism kinematics and dynamics analysis. Finite element analysis can complete mechanical analysis (linear, nonlinear, static, dynamic); field analysis (thermal field, electric field, magnetic field, etc.); frequency response and structural optimization, etc. Mechanism analysis can complete the calculation of the displacement, speed, acceleration and force of components in the mechanism, the simulation of the mechanism's motion and the optimization of the mechanism's parameters.
The role of CAE a) increase the design function, with the help of computer analysis and calculation to ensure the rationality of product design and reduce design costs;
b) Shorten the cycle time of design and analysis;
c) The "virtual prototype" role played by CAE analysis largely replaces the "physical prototype verification design" process that consumes a lot of resources in traditional design. The role of virtual prototype can predict the reliability of the product in the entire life cycle;
d) Use optimized design to find the best product design plan and reduce material consumption or cost;
e) Identify potential problems before product manufacturing or engineering construction;
f) Simulate various test programs to reduce test time and funds;
g) Perform mechanical accident analysis to find the cause of the accident.
In the early 20th century, a large amount of manpower and material resources were invested in the development of finite element analysis programs with powerful functions in the early 20th century. The most famous of these is the NASTRAN finite element analysis system commissioned by the National Aeronautics and Space Administration (NASA) in 1965 and commissioned by the American Computational Science Corporation and Bell Aerosystems. Since then, there are products from ASKA in Germany, PAFEC in the UK, SYSTUS in France, ABAQUS, ADINA, ANSYS, BERSAFE, BOSOR, COSMOS, ELAS, MARC and STARDYNE in the United States.
In 1979, the SAP5 linear structural static and dynamic analysis program of the United States was successfully introduced and transplanted into the country, setting off a climax of applying general finite element programs to analyze computational engineering problems. The finite element analysis systems that have been successfully developed in China and have more users (more than 100) include FIFEX95 of the Department of Engineering Mechanics of Dalian University of Technology, SAP84 of the Department of Mechanics and Scientific Engineering of Peking University, MAS5.0 and MAS5.0 of the Chinese Academy of Agricultural Machinery MFEP4.0 of Hangzhou Automation Technology Research Institute.
One of the important signs to measure the technical level of CAE is the development and application of analysis software. Large-scale general-purpose finite element analysis software such as ABAQUS, ANSYS, NASTRAN has been introduced into China, and it has been applied in many industries such as automobile, aviation, machinery, and materials. The development of computer analysis software in China is a weak link, which severely restricts the development of CAE technology. Taking only finite element calculation and analysis software as an example, the world's annual market share has reached 500 million US dollars, and is increasing at a rate of 15% per year. In contrast, China's own CAE software industry is still very weak, with only a small market share.
In the 1960s and 1970s, finite element technology was mainly developed for structural analysis to solve structural strength, stiffness, and modal experimental and analytical problems in aerospace technology. Three major CAE companies in the world have been established, dedicated to the research and development of large-scale commercial CAE software.
MSC was established in 1963, and developed structural analysis software called SADSAM (Structural Analysis by Digital Simulation of Analog Methods). In 1965, MSC participated in the research on the calculation structure analysis method initiated by the National Aeronautics and Space Administration (NASA), and its program SADSAM was renamed MSC/Nastran.
Structral Dynamics Research Corporation (SDRC) was founded in 1967, and released the world's first dynamic testing and modal analysis software package in 1968. In 1971, the commercial finite element analysis software Supertab (later incorporated into I-DEAS) was launched.
In 1970, Swanson Analysis System, Inc. (SASI) was established. Later, after reorganization, it was changed to ANSYS and developed ANSYS software.
The 1970s and 1980s were the period of vigorous development of CAE technology, during which many CAE software companies were established one after another. Such as the development of MARC for advanced engineering analysis general finite element programs; MDI for mechanical system simulation software development; CSAR for large structures, fluid-structure coupling, thermal and noise analysis; for structural, fluid and ADIND for fluid-structure coupling analysis, etc.
During this period, the finite element analysis technology has achieved great success in the field of structural analysis and field analysis. From the mechanical model to the analysis of various physical fields (such as temperature field, electromagnetic field, acoustic wave field, etc.), from linear analysis to nonlinear analysis (such as nonlinear material, nonlinear caused by large geometric deformation, caused by contact behavior Non-linear boundary conditions, etc.), from a single field analysis to the coupling analysis of several fields. Many well-known analysis software such as Nastran, I-DEAS, ANSYS, ADIND, SAP series, DYNA3D, ABAQUS, etc. have appeared. The development of software mainly focuses on the matching of calculation accuracy, speed and hardware platform. The users are mostly experts and concentrated in several fields such as aviation, aerospace and military. In terms of software structure and technology, these CAE software are basically structured software design methods, structured software developed in FORTRAN language, and its data management technology still has certain defects, and the operating environment is limited to large-scale computers and high-end at that time. workstation.
Since the 1990s, in order to meet the market demand and adapt to the rapid development of computer hardware and software technology, CAE developers have greatly expanded the functions and performance of the software, especially the user interface and the front and rear processing capabilities, and the internal structure of the software. And some modules, especially the data management and graphics processing parts, have undergone major transformations, so that the CAE software basically meets the needs of users in terms of function, performance, usability and reliability, and adaptability to the operating environment. They can be super parallel Computers, distributed microcomputer clusters, large, medium, small and micro computers and various operating systems platforms.
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FPGA Virtex-5 FXT Family 65nm Technology 1V 1136-Pin FCBGA
CPLD CoolRunner -II Family 12K Gates 512 Macro Cells 128MHz 0.18um Technology 1.8V 256-Pin FTBGA
CPLD CoolRunner -II Family 12K Gates 512 Macro Cells 128MHz 0.18um Technology 1.8V 208-Pin PQFP
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