1. Introduction to finite element method
The finite element method (Finite Element Method, FEM for short), as a powerful numerical calculation method, is the greatest advancement in computational mechanics in the past fifty years. Its appearance is closely related to its growth and the great invention of the 20th century-the computer. Its application field has spread all kinds of physical field analysis (such as temperature field, electric field, magnetic field, seepage field, acoustic wave field, etc.), from mechanical linear analysis to nonlinear analysis (such as material behavior nonlinearity, nonlinearity caused by geometry, Non-linearity caused by contact behavior, etc.), from a single field analysis to a coupled analysis of several fields. Especially in the concrete practice of civil engineering, water conservancy, machinery, aviation, aerospace, shipbuilding and other engineering technology fields, it has been transformed into productivity that directly promotes scientific and technological progress and social development, and exerts huge economic and social benefits.
At the same time, with the emergence and rapid development of finite element and computer technology, the development of finite element analysis programs has gradually become an independent discipline and industry. More and more finite element programs can solve various complex engineering problems on personal computers. Finite element methods and finite element software have become the basic tools and effective methods for many high-tech scientific and technological researches.
The finite element method program can be divided into three main parts in the overall composition: pre-processing part, finite element analysis part, post-processing part. The main program is the core of the finite element analysis program, which performs finite element calculations based on the data files of the discrete numerical model. The principle of finite element analysis and the numerical methods used are also concentrated here, which is the key to the accuracy and reliability of finite element analysis.
The pre-processing program automatically or semi-automatically generates the numerical file of the discrete model according to the simple description of the calculation model provided by the user, and outputs it in the form of a grid diagram for the user to view and modify. On the other hand, the post-processing program intuitively expresses the finite element calculation results in the form of graphics, which is convenient for users to grasp the situation of the analysis object. At present, for finite element programs that are better used for actual problem analysis, the amount of pre- and post-processing procedures often exceeds the main program of finite element analysis. The stronger the pre- and post-processing functions, the more convenient the use of the program by engineers and technicians.
2. Introduction of several major finite element analysis software
Finite element analysis is a modern calculation method developed rapidly for structural mechanics analysis. It is an effective numerical analysis method first applied in the field of continuum mechanics in the field of aircraft structure static and dynamic characteristics analysis in the 1950s, and it was quickly and widely used to solve continuity problems such as heat conduction, electromagnetic field, and fluid mechanics. The most popular finite element analysis software at present are: ANSYS, ADINA, ABAQUS, and MSC are four well-known and relatively large companies. Among them, ADINA and ABAQUS have strong capabilities in nonlinear analysis. Currently, they are the two most recognized finite elements in the industry. Analysis software, ANSYS and MSC entered China relatively early, so they are well-known and widely used in China.
At present, in terms of multiphysics coupling, several major companies can perform coupling analysis of structure, fluid, and heat, but the other three must be combined with other software for iterative analysis except ADINA. The only software that can achieve true fluid-structure coupling Only ADINA.
2.1 Software comparison
ANSYS is a relatively early commercialized software, and the company has acquired many other software under its umbrella. ABAQUS focuses on structural analysis and currently does not have a fluid module. MSC is an older piece of software that is currently slow to update. ADINA is a software with structural, fluid, and thermal analysis developed under the same system. It is powerful but has not yet been fully rolled out when it entered the Chinese market relatively late.
Structural analysis ability ranking: ABAQUS, ADINA, MSC, ANSYS
Fluid analysis ability ranking: ANSYS, ADINA, MSC, ABAQUS
Coupling analysis ability ranking: ADINA, ANSYS, MSC, ABAQUS
Cost-effective ranking: the best is ADINA, followed by ABAQUS, again ANSYS, and finally MSC
2.2 Comparative analysis of ABAQUS software and ANSYS software
2.2.1 Reputation in the world
The two softwares are both internationally renowned finite element analysis software, and have their own extensive user groups worldwide. ANSYS software has a good reputation among users dedicated to linear analysis. It has also made great contributions to the use of computer resources and user interface development. ABAQUS software is dedicated to more complex and in-depth engineering problems, and its powerful nonlinear analysis function has been widely recognized by high-end user groups in design and research. Since ANSYS products entered the Chinese market earlier than ABAQUS, and five years ago, ANSYS’s interface was one of the best interfaces at the time, so in China, ANSYS software is higher than ABAQUS in terms of number of users and market promotion. However, with the establishment of ABAQUS Beijing office, the number of users and market share of ABAQUS software are increasing substantially and steadily, and it is expected to catch up with and surpass ANSYS in the next few years.
2.2.2 Application areas
ANSYS software focuses on the expansion of application fields, and currently covers a wide range of research fields such as fluids, electromagnetic fields and multi-physics coupling. ABAQUS concentrates on research in structural mechanics and related fields, and is committed to solving deep-seated practical problems in this field.
2.2.3 Cost performance
ANSYS software has a variety of sales plans due to its flexible price policy, and it has a better cost performance when solving conventional linear and coupling problems. But in actual engineering, nonlinearity is a natural phenomenon far more common than linearity, and linearity is usually just an idealized assumption of nonlinearity. With the improvement of the level of research and the deepening of research problems, nonlinear problems will inevitably become a topic faced by engineers and researchers, and become a bottleneck restricting in-depth research and precise design. Buying ABAQUS software can solve these problems well, shorten the development cycle, reduce the test investment, and avoid redesign. If a worker wants to do his job well, he must first sharpen his tools. The cost of using inappropriate or low-grade analysis tools to work is far more than the cost of using appropriate tools. Therefore, in terms of comprehensive benefits and long-term benefits, the economy of ABAQUS software is also very prominent.
2.2.4 Solver function
For conventional linear problems, both software can solve well, and they are relatively close in terms of model size limitation, calculation process, and calculation time. ABAQUS software has obvious advantages in solving nonlinear problems. Its nonlinearity covers many aspects such as material nonlinearity, geometric nonlinearity and state nonlinearity. In addition, because ABAQUS/Standard (general program) and ABAQUS/Explicit (explicit integration) are both products of ABAQUS, the data transfer between them is very convenient, and the combination of preload, static and dynamic forces can be easily considered The calculation situation. The solver of the ABAQUS software is an intelligent solver, which can solve the nonlinear problems that other software does not converge, and other software also converges. The calculation of the ABAQUS software has a faster convergence speed and is easier to operate and use.
2.2.5 Human-computer interaction interface
ABAQUS/CAE is a software operating platform recently developed by ABAQUS. It draws on the advantages of similar software and CAD software, and is closely integrated with the ABAQUS solver software. Compared with other finite element software interface programs, ABAQUS/CAE has the following characteristics:
It adopts CAD modeling and visualization window system, which has good human-computer interaction characteristics.
Powerful model management and load management methods provide convenience for modeling and simulation of multi-task and multi-working actual engineering problems.
In view of the universality of contact problems in actual projects, a separate interaction module is set up to accurately simulate multiple contact problems in actual projects.
The parametric modeling method is adopted to provide a powerful tool for the parameter design and optimization of the actual engineering structure, and the structure modification.
2.2.6 Comprehensive performance comparison
Taken together, ABAQUS software has:
More unit types, up to 433 types of units, provide more room for choice, and can more deeply reflect the subtle structural phenomena and differences between phenomena. In addition to conventional structures, the mechanical behavior of actual structures such as pipes, joints and fiber reinforced structures can be easily simulated
There are more material models, including material constitutive relations and failure criteria, and there are only 16 rubber material models. In addition to conventional metal materials, it can also effectively simulate special materials such as composite materials, soil, plastic materials and high-temperature creep materials
2.3 Comparative analysis of ANSYS software, ABAQUS and ADINA
2.3.1 Popularity in the world:
The three softwares are both internationally renowned finite element analysis software, and have their own extensive user groups worldwide. ANSYS software has a good reputation among users dedicated to linear analysis; ABAQUS software is dedicated to complex and in-depth nonlinear engineering problems; ADINA software, in addition to solving nonlinear problems, has its multi-physics fluid-structure coupling solution function It is also the only patented technology in the world.
2.3.2 Application areas:
The three softwares are both large-scale general-purpose analysis softwares, and all have their own broad application areas. ANSYS focuses on the expansion and merging of application fields, and currently covers a very wide range of research fields such as structure, temperature, fluid, electromagnetic field and multi-physics coupling; ABAQUS only has structural analysis functions, and its functions are limited to the field of structural mechanics; and ADINA software Like ANSYS software, it includes the functions of structure, temperature, fluid and fluid-solid coupling, so its application fields are quite extensive.
2.3.3 Cost performance
The three kinds of software are the finite element analysis software of the United States, and the price difference is not particularly large. However, because the ABAQUS software only has the function of structural analysis, the ABAQUS software is the cheapest overall; but if you need to perform fluid calculation or If the multi-physics coupling solves the function, I believe that ANSYS software and ADINA software will be better choices.
2.3.4 Solver function
For conventional structural linearity problems, the three kinds of software can be better solved, and they are relatively close in terms of model scale limitation, calculation process, and calculation time. ABAQUS software and ADINA software have obvious advantages in solving nonlinear problems; while ANSYS software and ADINA software have unparalleled advantages in the coupling function of fluid and multiphysics.
2.3.5 Human-computer interaction interface
ANSYS/Workbench, ABAQUS/CAE, ADINA/AUI are all CAD modeling and visualization window systems, and they all have good human-computer interaction characteristics. In addition to providing window operations, all three softwares also provide command stream input, but ABAQUS/CAE does not support CAE interface operations for all command streams.
2.3.6 Modeling method
ANSYS software and ADINA software both use Parasolid as the core solid modeling technology, so it can achieve truly seamless two-way data exchange with other Parasolid as the core CAD software, and the two softwares have powerful modeling functions. The CAE module and the input file of the ABAQUS software were developed by two different companies. The CAE module function is not very complete. Some functions can only be realized by editing the INP input file.
2.3.7 Meshing
All three softwares provide a variety of mesh dividers, which can perform free meshing of complex models. In addition to common meshing, ANSYS software and ADINA software can also perform automatic hexahedral meshing of complex models, thereby ensuring the accuracy of the mesh while saving technicians’ work time.
2.3.8 Comprehensive performance comparison
The command flow operation of ANSYS software is very convenient, and it has advantages in structural loop optimization, but it is currently only limited to linear aspects, and the function of nonlinear aspects is poor and basically not; ABAQUS software has some characteristics in terms of explicit nonlinearity, but Implicit nonlinearity is inferior to ADINA and does not have the function of fluid; ADINA software is excellent in structural nonlinearity and multi-physics coupling. It is one of the most powerful finite element software in the world with nonlinear functions, and it has The world’s best fluid-structure coupling analysis function.
