Finite volume method in sai systems. Modern CAE automation systems for engineering calculations

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In this article I would like to share my experience of working with one little-known commercial CAE program.

The name of this program is GiD, and before moving on to the description, I would like to briefly talk about how I came to use it.

Prologue

I am a student at one of the technical faculties, one of the Siberian universities. Because there is no need (and just to be on the safe side), I won’t go into specifics. At the faculty, students of some departments are taught a course in computational mechanics. Of course, with a high-quality study of such a discipline, it is impossible to do without the appropriate software, and the department had one. Moreover, it was developed at the same department, successfully performed its functions (for many years) and at the time of its creation was quite relevant.

More specifically, it was a set of a program for creating finite element meshes and pre/postprocessing (Pascal using DOS graphics), a calculation program based on the finite element method (fortran 75) and a mesh optimizer (also fortran). The interaction between these programs was carried out with the help of armed knowledge and command line student.

The process of creating meshes was not entirely convenient and very labor-intensive, like the rest of the process of solving problems using this software package. Against the backdrop of the ever-growing variety of various modern CAE systems, this complex began to look outdated, and the question arose about its replacement. The search has begun...

I won’t describe the searches themselves in detail; that’s not what this is about. I will only note that a combine like ANSYS was not suitable for these purposes (especially since the faculty allocated as much as one for it). separate course lectures). Among the many open source projects there was also no obvious candidate that met our requirements. Eventually, after taking the advice of my supervisor, I started looking at GiD.

Personal pre/post processor

As a result, it turned out that this complex consists of:

a graphical preprocessor with a fairly powerful geometric modeling engine, discretization of geometric models and good capabilities for importing geometry and meshes from other CAE/CAD programs
a good and fairly simple graphical post-processor that allows you to analyze the results of the calculations performed

Several screenshots

I’ll immediately note one of the features of GiD, which subsequently prompted me to use it for the purposes described in the introduction. GiD does not come with a single calculation program that solves certain problems, but it is possible to use for these purposes any third party program . It would be more correct to call this not a feature, but the main idea.

Thus, the program in question is a universal pre/post processor that can be used to solve a wide variety of problems.

Most likely, this is not the only program that performs such functions, and I will be very grateful to those who provide examples. But it just so happened that I began to work with her. Moreover, the demo version did not impose any restrictions on the period of work with the program and on its functionality, except for the limitation on the number of nodes used in the grid (no more than 1010 nodes). That is, for educational purposes it could be used, generally speaking, for free.

The price of the product, by the way, is also very reasonable (just don’t take this information as advertising). On top of that, the developers provide versions for various platforms, which was very convenient, since I use Ubuntu, and the department’s machines have either XP or Seven.

We decided to replace the outdated pre/post processor of the software package we use with GiD, leaving the same calculation program.

How it works?

In order to organize communication between the GiD pre/post processor and some solver(forgive me if it hurts anyone’s ears, but in my vocabulary there is no Russian equivalent to the word solver), flexible and fairly simple mechanisms are used, which I will briefly discuss with examples.

So we have:

own calculation program for calculating the SSS of plates based on FEM
commercial pre/post processor

And it is necessary we can figure out from this a working, simple and convenient CAE system, suitable for certain purposes (in my case, training to work with similar systems)

Detailed instructions for this process, as well as guidance for working in the pre/post processor, are described in detail in the manuals from the developers. On the product website you can generally find a lot of affordable and useful information, from FAQ to materials of conferences dedicated to working with GiD. And thanks to the efforts of a certain

Irene Grigorieva from University of Kemerovo

the user manual is available in Russian (although, in my opinion, the developers themselves could have done this).

I will only touch on the main aspects.

Template system

GiD communicates between its preprocessor and solver by exchanging data files (ANSI type). If you want to use it to work with a program that uses any unformatted (or proprietary format) files as input data for its calculations, then most likely you will not succeed. Although it is possible that some module/addition may appear, or may already have appeared.

In order to transfer information about the model built (or imported) in the preprocessor to the solver input file, the system is used templates. The template is a file with the .bas extension, written in accordance with the rules invented by the developers, which tells the preprocessor in what form it should write the mesh data to the file.

A pattern consists of a set of any characters in which all characters except keywords, following the symbol " * ", GiD perceives it as plain text and transmits it in the same form to the input file.

Below are some examples of “template-result” for clarification.

Example 1. Displaying the total number of mesh elements and nodes

myproblem.bas
Myprogram datafile NumberOfNode = *NPoin NumberOfElements = *NElems

projectname.dat
Myprogram datafile NumberOfNode = 12 NumberOfElements = 10

Example 2. List of elements

myproblem.bas
ElemsList Elem Node1 Node2 Node3 Material Elemtype *Loop elems *ElemsNum *ElemsConec *ElemsMat *ElemsTypeName *End elems

projectname.dat
ElemsList Elem /Node1 Node2 Node3 / Material 1 / 1 2 12 / 1 2 / 2 11 12 / 2 3 / 2 3 11 / 2 4 / 3 10 11 / 2 5 / 3 4 10 / 2 6 / 4 9 10 / 1 7 / 4 5 9 / 1 8 / 5 8 9 / 1 9 / 5 6 8 / 2 10 / 6 7 8 / 2

Example 3. Creating variables. Formatted output.

myproblem.bas
*Set var pi= 3.1415926535897 *Set var circlelength *Set var radius=15 *format(IRadius=15, CircleLength=%5.3f) *operation(2*radius*pi)

projectname.dat
Radius=15, CircleLength=94.245

I think these examples should be enough for a clear explanation. In my opinion, everything is simple and does not require the user to know any programming language. In order to master the basic set of lexemes used in the template, a few hours will be enough.

This set contains standard cycles, conditions, cycles by elements, and message boxes, for error notifications, and much more. If the standard set is not enough, due to the complex format of the input file, or the need to implement some tricky functions, then in the template you can use procedures written in the Tcl language (both from the included library and written by the user). The Tcl interpreter is included, so you don't have to worry about installing it.

Problems of a specific task

Everything is clear with grids and templates. But this is not enough to solve a specific problem, because each problem has its own problems, and hence the presence various types(and ways of describing them) materials, boundary conditions and other features.

In order to be able to operate with this data set, you again need to create text files with the appropriate extensions.

.cnd- to describe the boundary conditions you use
.mat- to describe materials, and third
.prb- for other parameters.

Creating these files is still easier than creating templates. Here is an example of a file that describes two boundary conditions (the load at the node, and the initial movement of the node)

myproblem.cnd
CONDITION: Point-Move CONDTYPE: over points CONDMESHTYPE: over nodes QUESTION: X-Move VALUE: 0 QUESTION: Y-Move VALUE: 0 HELP:movement(cm) END CONDITION CONDITION: Point-Force-Load CONDTYPE: over points CONDMESHTYPE: over nodes QUESTION: X-Force VALUE: 0.0 QUESTION: Y-Force VALUE: 0.0 HELP: Load(cm) END CONDITION

After creating all the above files, you need to “put” them in a folder with any name you like (which will subsequently be used in the program interface as your task identifier) and “extension” .gid. This folder should be placed in one of the subdirectories of the GiD program; the next time you start it, your task type will be available for work.

Projects are stored in folders with the same “extension” .gid. Data files obtained using templates are also placed there, as well as files with boundary conditions and materials are duplicated (to be able to change them in relation to only one project). There can be as many templates as you like, and each of them will have its own data file.

Ready! How to start?

When the model is built, the mesh is generated, and the boundary conditions are specified, you need to run the solver. To be able to do this directly from the preprocessor, you need to write a simple script. When you click the “Caclulate” button in GiD, the program will simply run this script with three parameters (project name, path to the project folder, path to the folder with the task type definition). You can implement everything you were missing in the script using CMD on Windows or bash/sh on Linux.

What about the post-processor?

With a post-processor, unfortunately, everything is not so flexible. It requires the calculation program to output data to files in the format it desires. A more convenient system has not yet been invented.

In my case, this problem was solved by creating a “converter”, which, based on the output files of our calculation program, created the files needed by the postprocessor. The format of these files is described in detail in the manuals, and creating such a “converter” will not be difficult, provided you have minimal skills in working with files in any programming language.

Summarizing

GiD may be useful for those who are looking for a simple and convenient pre/post processor for solving a wide variety of problems, but at the same time do not want to acquire such giants as ANSYS (even the most basic kit of which includes many, sometimes unnecessary and unnecessary functions for engineers/researchers, for which, like it or not, you will have to pay).

This program can also be a solution for those who cannot find a CAE that can do what they need, but at the same time have their own solver (or are planning to create one).

I hope this material will be useful to someone.

Lecture 18. CAE systems

Parameter name	Meaning
Article topic:	Lecture 18. CAE systems
Rubric (thematic category)	Electronics

A set of criteria for comparing FE analysis systems

The main factors for choosing CAE systems are the composition of the tasks to be solved; reliability of calculation results; CAD integration; ease of learning. This general list must be detailed for each application area of the systems.

For CAE systems, as for CAD systems, it is possible to distinguish common (standard) capabilities for all and additional functions implemented only in individual systems. General indicators of functionality include the number of types of finite elements, the number of types of boundary conditions, productivity both in preparing the model and in solving standard problems, and additional features- setting boundary conditions for FE analysis problems directly in the CAD module with transfer to the CAE module; programming capabilities (for example, in ANSYS - APDL language, in CFX - CEL language), etc.

An example of a set of criteria for comparing FE analysis systems

A comparative analysis of structural calculation systems carried out by the Council of International Strategies and Management (France, 1992-1993) included testing on 352 parameters, including

· ease of preparation of initial information;

· speed of automatic generation of finite element models (plane and spatial);

· speed of solving a system of linear equations using the FE method;

· composition of the CE library;

· the ability to calculate geometric characteristics (moments of inertia during bending, torsion and shear) for sections of arbitrary shape;

· control of the calculation model for objects that lose stability during loading;

In the context of choosing a FE analysis system for the tasks of a particular design bureau, a detailed study of such a large number of indicators is hardly possible. An example of a shortened set of tests for a relatively quick comparative assessment of the capabilities of mid-level systems is given in the series of articles by A. Avedyan and A. Danilin “Strength is not for strength specialists” [CAD and graphics, 2000, No. 1, 2, 3, 5].

The systems of “Golden Partners” SolidWorks, fully integrated into the CAD system environment, were subjected to a comparative analysis. Comparison based on 10 criteria˸

· Range of tasks to be solved.

· Complexity of the problems to be solved (10 problems of different levels of complexity both in terms of the geometry of the model and the content of the analysis).

· Reliability of the results (comparison with known analytical solutions of several problems - bending and vibration of a beam, deflection of a round plate, stretching of a shaft with a groove, heating of a thick-walled cylinder, etc.).

· Possibility of setting boundary conditions and loads.

· Ability to work with materials database.

· The degree of user influence on the accuracy of calculations.

· Accessible to structural engineers without extensive strength training.

· Quality of results presentation and ease of working with the report.

Lecture 18. CAE systems - concept and types. Classification and features of the category "Lecture 18. CAE systems" 2015, 2017-2018.

CAD systems (computer-aided design - computer support for design) are designed to solve design problems and prepare design documentation (more commonly they are called computer-aided design systems - CAD). As a rule, modern CAD systems include modules for modeling a three-dimensional three-dimensional structure (parts) and designing drawings and text design documentation (specifications, statements, etc.) Leading three-dimensional CAD systems make it possible to implement the idea of an end-to-end cycle for the preparation and production of complex industrial products . CAD systems are widely used in architecture, furniture and interior design (ARC+ and Deco Design (France) systems), and web design.

CAM systems (computer-aided manufacturing - computer support for manufacturing) are intended for designing the processing of products on machines with numerical control (CNC) and issuing programs for these machines (milling, drilling, erosion, punching, turning, grinding, etc.) CAM- systems are also called systems for technological preparation of production. Currently they are practically the only way for the production of complex-profile parts and reducing their production cycle. CAM systems use a three-dimensional model of a part created in a CAD system.

CAE systems (computer-aided engineering - support for engineering calculations) represent a broad class of systems, each of which allows solving a specific calculation problem (group of problems), ranging from strength calculations, analysis and modeling of thermal processes to calculations hydraulic systems and machines, calculations of casting processes. CAE systems also use a three-dimensional model of the product created in a CAD system. CAE systems are also called engineering analysis systems.

PDM technology (Product Data Management) is designed to manage all product data and product life cycle information processes that create and use this data. Life cycle information process management is the support of various procedures that create and use product data (product change procedures), i.e. in fact, support for electronic document management (design document management). To implement PDM technology, there are specialized software, called PDM systems (i.e. product data management systems; another name is project management systems).

CAD/CAM/CAE/PDM systems are used in mechanical engineering. Integrated automation of design and engineering departments of design bureaus and industrial mechanical engineering enterprises based on modern computer technologies.

CASE technology (computer-aided software engineering) technology for creating and maintaining information systems. The term CASE is understood quite broadly today. The original meaning of the term, limited to issues of automation of software development, has now acquired a new meaning

/CAEs were Applicon, Auto-Trol Technology, Calma, Computervision and Intergraph. Since the mainframes of that time were imperfect, certain difficulties arose. The interactive mode of operation was practically unavailable due to the heavy load on CPU. The cost of one CAD/CAM/CAE system was about $90,000. With the development of progress, hardware platforms for CAD/CAM/CAE systems have moved from mainframes to personal computers. This was due to the lower cost and greater performance of PCs compared to mainframes. The price for CAD/CAM/CAE has naturally decreased to $20,000. PC-based CAD workstations were created that supported the IBM PC or Motorola architecture. In the mid-80s, microprocessor architectures with a truncated instruction set RISC (Reduced Instruction Set Computing) appeared. Based on them, more productive workstations were developed, based on the Unix operating system. Since the mid-90s, RISC/Unix systems have competed with technologies developed by Intel based on operating systems MS Windows NT and MS Windows 2000. Currently, the cost of CAD/CAM/CAE systems has decreased and is no more than $10,000.

Classification

Full-featured engineering analysis systems with powerful tools, large type repositories for finite element meshes, as well as all kinds of physical processes. They provide own funds geometry modeling. In addition, it is possible to import through industry standards Parasolid, ACIS. Fully functional CAE systems do not have an associative connection with CAD. Therefore, if during the calculation process there is a need to change the geometry, the user will have to import the geometry again and enter data for the calculation. The most famous such systems are ANSYS/Multiphysics, AI*NASTRAN and MSC.NASTRAN.
Engineering analysis systems built into heavy CAD systems have significantly less powerful analysis tools, but they are associative with geometry, so they track changes in the model. Calculation data is structured and integrated into common system heavy CAD design. These include Pro/MECHANICA for Pro/ENGINEER, Unigraphics NX CAE for Unigraphics NX, Extensive Digital Validation (CAE) for I-deas, Catia CAE for CATIA;
Mid-level engineering analysis systems do not have powerful calculation capabilities and store data in own formats. Some of them include an embedded interface in CAD systems, others read geometry from CAD. The first include COSMOS/Works, COSMOS/Motion, COSMOS/FloWorks for SolidWorks Three-dimensional design environment, the second - visualNastran, Procision.

StrAU capabilities

With the help of SAE you can:

Strength analysis of components and assemblies based on the finite element method;
Thermal and hydrodynamic analysis;
Kinematic studies;
Simulation of processes such as injection molding;
Optimization of products or processes.

Stages of working with StrAU

Pre-processing - determining the characteristics of the model and the environmental factors that will affect it;
Analysis and decision making;
Processing the results.

Applications

StrAUs are most popular in the following industries: mechanical engineering and machine tool building, defense and aerospace industries, energy, shipbuilding, semiconductor production, telecommunications, chemical, pharmaceutical and medical industries, construction, production of heating, air conditioning and ventilation systems.

Experience in using StrAU in the automotive industry

The advantage of CAE systems is that automakers can conduct computer testing of developed models. This allows you to focus maximum attention on improving the safety, comfort and durability of cars without spending financial resources. The safety of passengers in collisions can be assessed using such software products like RADIOSS, LS-DYNA, PAM-CRASH.

Main directions in the development of StrAU

In the process of developing StrAUs, developers strive to increase their capabilities and expand the scope of implementation. The following goals are pursued:

Improving methods for solving interdisciplinary modeling problems;
Development of new platforms for integration various systems CAE, as well as for integrating CAE systems into PLM solutions;
Increasing the interoperability of StrAU and CAD systems;
Improving methods for constructing computational grids, describing boundary conditions, parallel computing etc;
Improving the characteristics of models that are used to describe the properties of materials;
Optimization of StrAU systems for computer platforms with 64-bit and multi-core processors, thereby improving conditions for modeling complex structures with a large number of degrees of freedom.

World market

According to TechNavio's forecast (spring 2013), the CAE market will grow by 11.18% annually in the next five years and will reach $3.4 billion by 2016. This growth is due to a number of factors, the main one of which is the need to accelerate production products to the market. And the main obstacle, as in the case of CAD, is the growing popularity of systems with open source code, due to the high cost of licenses for commercial CAE systems.

Of the geographic regions, North America became the largest in terms of demand for CAE in 2012, and the Asia-Pacific region, where industry is actively developing, took first place in terms of growth rates.

CAE systems are most widely used in automotive and aircraft manufacturing, electrical engineering and electronics, heavy engineering and the defense industry. The highest growth in demand for CAE is expected in the automotive industry, and the smallest in heavy engineering.

Leading positions in the CAE market are occupied by Ansys, MSC Software, Dassault Systemes, CD-adapco Group and LMS International. There are many smaller companies in this area as well, but the number of CAE-only firms is dwindling as they are acquired by larger players for their technology.

In their commentary, analysts from TechNavio noted that some large global CAE and PLM vendors have begun to promote “globalized” licenses, which allow customers who purchase them to use CAE systems anywhere in the world and seek support services from the vendor’s office in any country. This allows vendors to eliminate differences in the cost of their products in different countries and sell them at the same price around the world. Analysts expect that this approach As more and more CAE and PLM vendors use them, there will be significant changes in the market in terms of vendor pricing policies.

Categories of tasks for which CAE (computer aided engineering) systems are most often used. Architecture and operating principle of a standard CAE package, main examples of systems: Salome, ANSYS (Swanson Analysis Systems) and MSC.Nastran, their characteristics.

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Introduction

The emergence and subsequent development of high-performance computing technologies was caused by the need to perform mathematical calculations for various studies. Despite the fact that the methods and algorithms for these calculations are not particularly complex, the volume of the calculations themselves is so significant that it is almost impossible for a small group of researchers to complete them in an acceptable time frame and with the proper quality.

The first engineering packages were created in the late 60s and early 70s specifically to automate routine calculations. In English-language literature, such packages are designated by the abbreviation CAE (computer aided engineering), and in Russia this concept is part of CAD (computer aided design systems). The tasks for which CAE systems are most often used can be divided into the following categories:

· strength calculations of various parts and assemblies (calculation of elastoplastic deformations and stresses);

· hydrodynamic calculations (calculation of the characteristics of various single- and multiphase flows, as well as their evolution over time);

· thermodynamic calculations (calculation of heating and cooling of parts and assemblies);

· calculation of electric, magnetic and electromagnetic fields;

· various combinations previous types of tasks.

architecture system principle operation

1. Architecture and operating principle of a standard CAE package

Most CAE packages are based on the finite element method. The idea of this method is to replace a continuous function describing the phenomenon or process under study with a discrete model, which is built on the basis of a set of piecewise continuous functions defined on a finite number of subdomains. Each such subregion is finite and represents a part (element) of the entire region, which is why they are called finite elements. The geometric region under study is divided into elements in such a way that on each of them the unknown function is approximated by a test function. This partition is called computational grid.

As an example, consider a cylindrical steel rod, one end of which is placed in a fire. The fragment of the rod exposed to the flame actively heats up. That is, a heat source acts on its cylindrical surface. The rest of the rod is heated only due to the phenomenon of thermal conductivity - the transfer of heat from hot areas to colder ones. In the roughest case, the rod can be divided into two parts: with a heat source on the cylindrical surface and with a heat source in the section of the cylinder parallel to the base. Thus, one complex (complex) task is divided into two simpler ones.

However, the resulting problems are still too complex to be solved in a general form, since their solutions represent complex exponential dependencies on coordinates and time. To simplify, you can divide the rod into smaller fragments (elements), and in the elements near the surface, set the heat release throughout their entire volume, and not just at the boundary (if certain conditions are met, this is justified), and in the remaining elements, due to their smallness, look for an approximate solution in the form of a simpler relationship (linear or quadratic). In this case a complex system differential equations for an element is reduced to a simpler system of algebraic equations. With this approach, finding a solution for each individual problem will be much easier.

The complexity of this approach lies in the need to solve large quantity such simplified problems. IN modern challenges grids with tens and hundreds of millions of elements are used. Therefore, engineering packages are created using parallel programming technologies to provide the necessary computing power.

Creating a good computational mesh is also a non-trivial task. This is due to the fact that real machine parts have complex geometry and it is necessary to divide them into such elements that the approximate solutions do not differ much from the exact ones. Therefore, in addition to the CAE packages themselves, there is big number applications that perform only one important function: constructing a computational mesh. In English-language literature, such applications are called mesher.

The module responsible for solving the system of equations corresponding to the generated mesh is called solver(in English literature: solver). It receives all the input data and processes it based on the methods implemented in it.

Currently, computer modeling using CAE systems makes up a significant portion of the work in any serious scientific or engineering project. There are well-known commercial solutions on the CAE systems market, for example, ANSYS, Deform, Simulia (formerly Abaqus) and others. The cost of licenses for these products amounts to hundreds of thousands and millions of rubles, but there are also CAE systems related to free software.

Among the free CAE packages, the most famous are: Salome, OpenFoam, Elmer. The main disadvantages of these packages include an undeveloped interface and lack of documentation, especially in Russian. However, the possibility of using them on any number of processors without any financial costs for purchase makes free CAE systems very attractive for use in small companies and educational institutions.

2. ExamplesCAE-systems

Salome

Most CAE packages are complete software packages that contain everything that is necessary to perform finite element modeling. Salome is a platform that provides task pre-processing and post-processing functions ( pre-processing And post-processing), i.e. there are definitions of geometry, construction of meshes, definition of the “trajectory” of calculations, visualization of results, etc. It lacks the most important components - solvers, but the Salome platform can be expanded with third-party free or commercial modules.

The main purpose of the Salome platform is to create a kind of unified environment, after studying which the user will be able to process the source and received data in a familiar shell, regardless of the solver used. It is possible to connect ANSYS and other commercial package solvers to this shell by writing special modules or control scripts that can be written in Python languages or C++.

The platform's internal language is Python, and the platform itself has a built-in Python console that can be used to run custom scripts and automate the processing of many common tasks (batch processing).

ANSYS

Finite element package. ANSYS, Inc. For 35 years, it has been one of the leaders of the SAE market, developing and offering a wide range of software products for automated engineering analysis. Founded by Mr. John Swanson, the company was originally called Swanson Analysis Systems, and offered only the ANSYS universal finite element package. Later, the program gave its name to the company itself. Today, the company is the leader in the settlement systems market both in terms of sales volume and the number of workstations of its software used around the world, and the breadth of the line and applicability of software products: ANSYS, AutoDYN, CFX, Fluent, ICEM, Maxwell. This is just a short list.

The ANSYS product line is wide and provides all the needs of the designer at all stages of his work, starting with the construction or modification of the geometric and mesh model, then moving on to effective solution tasks, and ending with processing, presentation and documentation of results. ANSYS SOLVES is a tool for solving problems of strength, thermophysics, and electromagnetism.

MSC.Nastran

general characteristics. MSC.Software's flagship product, MSC.Nastran, is the best finite element software system on the market. In an industry where unreliable results can result in millions of dollars in additional development costs, MSC.Nastran has proven its accuracy and efficiency for over 30 years. Constantly developing, it accumulates the advantages of the latest techniques and algorithms and therefore remains the leading finite element analysis program.

MSC.Nastran provides a complete set of calculations, including the calculation of stress-strain states, natural frequencies and mode shapes, stability analysis, solving heat transfer problems, the study of steady and unsteady processes, acoustic phenomena, nonlinear static processes, nonlinear dynamic transient processes, calculation of critical frequencies and vibrations of rotary machines, analysis frequency characteristics under the influence of random loads, spectral analysis and aeroelasticity research. It is possible to simulate almost all types of materials, including composite and hyperelastic. Advanced features include superelement (substructure) technology, modal synthesis, and the DMAP macro language for creating custom applications.

Along with structural calculations, MSC.Nastran can also be used to optimize projects. Optimization can be carried out for problems of statics, stability, steady and unsteady dynamic transients, natural frequencies and mode shapes, acoustics and aeroelasticity. And all this is done simultaneously by varying the parameters of the shape, size and properties of the project. Due to their efficiency, optimization algorithms handle an unlimited number of design parameters and constraints. Weight, stresses, displacements, natural frequencies and many other characteristics can be considered either as objective functions of the design (in which case they can be minimized or maximized) or as constraints. Sensitivity analysis algorithms allow you to explore the impact various parameters on the behavior of the objective function and manage the process of finding the optimal solution.

The extensive capabilities of the MSC.Nastran optimization function allow it to be used for automatic identification of a computer calculation model and experiment. The objective function is determined in the form of minimizing the discrepancy between the results of calculation and experiment; the least reliable design parameters of the structure are selected by varying parameters. As a result of optimization, MSC.Nastran produces a new computer model that fully matches the experimental model. MSC.Nastran is the only finite element program that can do this automatically.

MSC.Nastran also includes a unique design optimization feature with unlimited geometric changes (changing the geometric topology of an object) while minimizing weight and satisfying strength boundary conditions. This function allows you to use MSC.Nastran for the automatic design of power circuits of structures, when, based on a volumetric solid workpiece, MSC.Nastran automatically creates an openwork optimal design that best satisfies the specified conditions.

MSC.Nastran is also used for planning experiments (determining sensor locations) and assessing the completeness of the obtained experimental data.

With the help of MSC.Nastran, the problems of modeling control systems and thermal control systems are also solved, taking into account their impact on the structure.

Based on the automatic restart capabilities in MSC.Nastran, complex multi-step studies of the structure’s operation are carried out both when loading conditions, boundary conditions and any other design parameters change, and when moving from one type of analysis to another.

MSC.Nastran is based on proven element technology and reliable numerical methods. The program allows you to simultaneously use h- and p-elements in the same model to achieve calculation accuracy with minimal computer resources. The elements are super high order approximations - p-elements - well reflect the curvilinear geometry of the structure and provide high accuracy in detailed stress calculations. These elements automatically adapt to the desired level of accuracy. Numerical methods of sparse matrices, used for any type of calculation, dramatically increase the speed of calculations and minimize the amount of required disk memory, which increases the efficiency of data processing.

The close connection of MSC.Nastran with MSC.Patran provides a fully integrated environment for modeling and analysis of results. All leading manufacturers of pre- and post-processors, as well as computer-aided design systems, taking into account the undeniable leadership of MSC.Nastran in the market of finite element software products, provide direct interfaces with this system. As a result, MSC.Nastran can be flexibly integrated into any design environment you have.

MSC.Nastran runs on personal computers, workstations and supercomputers, provides the capabilities of vector and parallel data processing on computers that support these functions.

MSC.Nastran is:

Efficiency in solving large problems due to:

Application of the algorithm for processing "sparse" matrices

Automatic internal renumbering of matrices to reduce tape width

· Possibility of using “restart” in order to use the results already obtained at that moment

Application of parallel and vector computing algorithms

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