Z88 (software)
| Z88 | |
|---|---|
| Basic data
|
|
| developer | Frank Rieg |
| Current version | Z88V15OS Z88Aurora V5 Z88Arion V2 (July 17, 2017 / April 1, 2019 / April 23, 2018) |
| operating system |
Windows , Linux , Unix , macOS |
| category | FEM program |
| License | Z88V15 GNU GPL Z88Aurora V5 (Custom) |
| German speaking | Yes |
| z88.de | |
Z88 is a software package for the finite element method (FEM) and topology optimization in structural and continuum mechanics . The software has been developed by a team led by Frank Rieg at the University of Bayreuth since 1985 and is used by a number of universities in teaching and research as well as by several small and medium-sized companies in product development. Z88 can calculate two- as well as three-dimensional element types with a linear approach. The software includes several solvers and two post-processors. Z88 is platform-independent and is included in the SUSE Linux distribution . In 2007, benchmark comparisons of the solver showed performance not inferior to that of commercial programs.
History and functions
overview
The software was developed by Frank Rieg , a university professor for design and CAD at the University of Bayreuth . The original sources were written in Fortran 77. In the early 1990s, the program was ported to the C programming language .
There are two programs for finite element analysis:
- Z88OS (current version since July 2017: V15.0) is available as free software with source code under the terms of the GNU GPL . Due to the modular structure of the program and the availability of the source code, your own extensions can be incorporated and used. Several 2D and 3D continuum elements for special cases ( e.g. anisotropic shell element) have been developed by users.
- Z88Aurora (current version since April 2019: V5) originally referred to the graphical user interface for the finite element analysis program Z88. Due to various further developments, Z88Aurora now has a significantly larger range of functions than Z88OS. The software is freeware , but the source code is not disclosed.
In addition, there have been two apps for Android devices since 2014:
- Z88Tina is a freeware FEA program for Android smartphones or tablets. With Z88Tina, on the one hand, bars and beams and, on the other hand, continuum elements such as discs, plates or tori can be calculated.
- Like all Z88 products, Z88Mobile is free of charge. This app offers two different modes (Basic and Advanced) and can be operated via touch controls.
Since 2016 a program for topology optimization has been added to the Z88 product family:
- Z88Arion (current version since April 2018: V2) is a free program for topology optimization and has three optimization algorithms to choose from (OC: Optimality Criteria, SKO : Soft Kill Option, TOSS: Topology Optimization for Stiffness and Stress).
Functions of Z88Aurora
The current version of Z88Aurora contains the following calculation modules:
- In linear static analysis , it is assumed that the result is proportional to the applied loads.
- Nonlinear analyzes are used for geometric nonlinearities or material nonlinearities.
- With thermal and thermomechanical analyzes , in addition to results such as temperature or heat flow, thermomechanical displacements or stresses can also be determined. Since Z88Aurora V5, convection has also been implemented as a thermal boundary condition.
- The natural frequencies of the system can be determined through natural vibration calculations (modal analyzes).
- With the help of the contact module, interacting components or assemblies can be simulated. An integrated component management tool enables effective handling of the assemblies. There is the possibility of showing glued or frictionless contact. Furthermore, the type of contact (node-surface or surface-surface contact), the mathematical method (Lagrange, disturbed Lagrange or penalty method) and the direction of the contact stiffness (in tangential and normal direction) can be controlled via the contact settings become. Only linear and square tetrahedra and hexahedra can be used as element types in this module. Furthermore, the contact module is only available for linear, mechanical strength analyzes.
Regardless of the selected module, the finite element analysis with Z88Aurora can be divided into three areas: preprocessor, solver (processor) and postprocessor.
The FE model is built in the preprocessor. The structure to be calculated can be created directly in Z88Aurora from structural elements such as beams and bars or imported in various formats. Geometries can be read in in the form of STEP files (* .STP), STL files in ASCII and binary format (* .STL) or Autocad files (* .DXF). For FE structure data, NASTRAN (* .NAS), ABAQUS (* .INP), ANSYS (* .ANS) or COSMOS files (* .COS) can be imported. Z88Aurora contains a total of 25 different element types, including 2D elements (rod, beam, disk, shaft, torus ) and 3D elements (rod, beam, linear and square tetrahedron and hexahedron ). The networking takes place via two freeware tetrahedron networkers (TetGen by Dr. Hang Si (WIAS Berlin) and NETGEN by Prof. Joachim Schöberl (TU Vienna)). Furthermore, a tetrahedron refiner is used for existing tetrahedron networks (linear and square), a mapped mesher for super element structures (hexahedron, shells, etc.), a shell thickener that produces volume shells from 2D shells and a trimming function to create flat sections from 3D components (model reduction ) to refine the model. The set management enables a simple selection of areas, nodes and elements in order to link them with boundary conditions, materials etc. the material database contains 52 predefined materials and can be edited and expanded by the user. Various boundary conditions such as forces, displacements, pressure loads or thermal boundary conditions can be entered via the graphical user interface.
The solver calculates displacements, stresses, temperatures and nodal forces depending on the active calculation module. Z88Aurora offers four numerical equation solvers for linear finite element analysis: a direct Cholesky equation solver with Jennings storage for small beams and rod structures, two differently preconditioned, iterative equation solvers with sparse storage for large finite element structures and a multi-processor capable sparse -Solver for medium-sized finite element structures. The iterative equation solver and the direct multicore equation solver are used for stationary thermal or thermomechanical calculations. An iterative solver is available for non-linear calculations. The equation solver for natural vibration calculation uses the Lanczos method.
The results from the solvers are visualized in the post-processor. Filtering of the results and clipping of the component is possible. In addition, various representations and elements can be shown and hidden. Individual results can be exported in text or CSV format and the analysis function makes it possible to output values from individual nodes. In addition, the deformed structures can be output in STL format and thus further processed in other programs. An image export of the current model view is also possible for simplified documentation.
The software has a Windows user interface with context-sensitive online help. Manuals show how to use the Z88 and Z88Aurora using examples.
The freeware is available for Windows, Linux and OS X.
Functions of Z88Arion
In topology optimization, an existing structure is optimized with regard to a specified target function by changing the topology class in a defined installation space. The aim is to create an optimal structure by removing material in suitable places. The aim of topology optimization is to enable the automatic generation of an optimal structure under defined loads in the virtual product development process. The basis is an initial draft. A structural analysis provides system responses such as deformations, stresses or natural frequencies, which are evaluated by the optimization model. At this point the model and design variables for optimization are defined. Not only the objective function, but also secondary conditions and restrictions are specified. The optimization problem is solved using an algorithm that varies the properties of the design variables. At the end there is an improved design, which runs through the loop until an optimal design, the so-called design proposal, is achieved.
With Z88Arion, the user can choose between the following methods, depending on the goal of topology optimization :
- Optimality Criteria (OC)
- Soft Kill Option (SKO)
- Topology Optimization for Stiffness and Stress (TOSS)
The OC method generates a design proposal that has a minimum flexibility or maximum stiffness in relation to a previously determined relative volume. The SKO process is optimized for maximum strength. The TOSS algorithm specially developed by the chair represents a combination of both methods. This hybrid process from OC and SKO refers to the optimal, rigid structure of the OC process and generates a stress-optimized design proposal from it. In doing so, material is deposited again in over-loaded areas and removed in under-loaded areas.
The determined design proposal is displayed in the postprocessor. The user can e.g. B. to consider different iterations and to vary the display limits. Since Z88Arion V2 it has also been possible to smooth the resulting structure and export it as an STL in order to ensure that the optimized component can be used directly in other programs. There is also a direct interface to Z88Aurora.
commitment
Use in research and teaching
Since 1998, Z88 has been used to train engineering students as part of lectures at the University of Bayreuth. Through the possible manual input of the structural and boundary condition data as well as the load sets, it shows the students how a finite element program works. Due to the open file sources, the software can be used for research purposes in the FE area and modified accordingly.
Among other things, Z88 is used in teaching and research at the HS Ravensburg-Weingarten , the University of Ioannina , the Penn State University, the Universidad de Buenos Aires , the University of Cagliari , the University of Maribor , and at the Zonguldak Karaelmas Üniversitesi. In the context of diploma and seminar work, Z88 has so far been used at the universities of Darmstadt, Hamburg-Harburg, Munich, Karlsruhe, Bern and Beijing, among others.
In addition to face-to-face courses, Z88 is used in two mechanical engineering textbooks. The book Finite Element Analysis for Engineers: An Easy-to-Understand Introduction has been sold over 6,000 times. This technical book is aimed at beginners in finite element analysis and uses Z88 so that the reader can understand all the examples given in the book on their own computer. In the textbook Machine Elements - Function, Design and Calculation by Decker (19 editions so far), the calculation of machine elements with finite element analysis is taught on the basis of practical applications with Z88.
Use in industry
Due to the open source approach, many applications use Z88 solvers, plot outputs and the like. Among other things, Z88 has been extended for a program for calculating point and line loads on glass plates in building construction. Routines have been implemented for the determination of the modulus of elasticity and flexural strength of wood and a sub-program in Z88 for the calculation of pressure vessels has been developed. Z88 is used by
- Boeing: Missile Defense Systems (USA),
- Teledyne Brown Engineering (USA),
- Winimac Coil Spring Inc. (USA),
- Double D Design Ltd. (New Zealand),
- RINGSPANN GmbH (Germany),
- KTR Kupplstechnik GmbH (Germany) and
- Neuson Hydrotec GmbH (Austria)
used.
Due to the availability of the program code and thus the traceability of the algorithms and material models used, Z88 has repeatedly served as a comparison calculation program for commercial tools such as Nastran and ABAQUS .
literature
- Frank Rieg, Reinhard Hackenschmidt, Bettina Alber-Laukant: Finite Element Analysis for Engineers: An easy to understand introduction . Hanser Fachbuchverlag, Munich / Vienna 2014, 5th edition, ISBN 978-3-446-44283-2 .
- Karl-Heinz Decker: Machine elements - function, design and calculation . Hanser Fachbuchverlag, Munich / Vienna 2014, 19th edition, ISBN 978-3-446-43856-9 .
- Frank Rieg: Z88 - The compact finite element system .
Web links
- Official website
- Z88 user forum of the University of Bayreuth
- Z88 user forum from CAD.DE
- Frank Rieg's chair at the University of Bayreuth
Individual evidence
- ↑ Roith, B .; Troll, A .; Rieg, F .: Integrated Finite Element Analysis (FEA) in three dimensional Computer Aided Design programs (CAD) - overview and comparison . ICED'07, Paris, 2007.
- ↑ Martin Zimmermann: Theory and implementation of displacement-related shells as finite elements in mechanical engineering . Shaker, 2008, ISBN 978-3-8322-7528-0 .
- ↑ a b Frisch, M .: Development of a hybrid algorithm for the rigidity and stress-optimized design of construction elements . Shaker, Aachen, 2015, ISBN 978-3-8440-4028-9 .
- ↑ Frisch, M., Deese, K., Rieg, F., Dörnhöfer, A .: Further development and use of a method for topology optimization to increase efficiency in the concept phase . NAFEMS, Bamberg, 2016, ISBN 978-1-910643-03-7 .
- ↑ Bendsoe, MP, Sigmund, O .: Topology Optimization . Springer, 2004, ISBN 3-540-42992-1 .
- ↑ Work at the Ravensburg-Weingarten University of Applied Sciences, Faculty of Mechanical Engineering, Finite Elements course, with Edmund Böhm . (Retrieved August 27, 2012.)
- ↑ Use at the University of Ioannina, Institute of Mechanics, Greece, course Introduction of Finite Elements, with Ioannis Stavroulakis ( Memento from October 3, 2015 in the Internet Archive ). (Retrieved August 27, 2012.)
- ^ Institute for Accoustics, America, Reagor, Cameron Paul ( Memento from August 5, 2012 in the web archive archive.today ). (Retrieved August 27, 2012.)
- ↑ Facultad de Ingenieria, Argentina, Analisis Numerico I . (Retrieved August 27, 2012.)
- ↑ L'Universita Di Cagliari , Dipartimento di Ingegneria Strutturale, Italy (accessed August 27, 2012).
- ^ Faculty of Mechanical Engineering, Laboratory for intelligent CAD Systems, Slovenia Bojan Dolsak ( Memento from April 1, 2012 in the Internet Archive ). (Retrieved August 27, 2012.)
- ↑ Faculty Bartin Orman, Turkey, Gökhan Gündüz . (Retrieved August 27, 2012.)