# Z88 FEM software

Z88 is a software package for the finite element method ( FEM) in structural and continuum mechanics. The software is developed by a team under the direction of Frank Rieg at the University of Bayreuth since 1986 and used by a number of universities in teaching and research as well as several small and medium-sized enterprises in product development. Z88 can calculate both two - and three-dimensional elements with linear shape types. The software also includes several solvers and two post- processors. Z88 runs platform independent and is included in the SUSE Linux distribution. 2007 occurred benchmark comparisons of the solver a power that is not inferior to the commercial programs.

## History and Functions

The software was developed by Frank Rieg, a University Professor of Engineering Design and CAD at the University of Bayreuth. The original sources were written in FORTRAN 77. In the early 1990s, the program has been ported to the C programming language. There are two versions of the program:

- Z88 (current version 14.0 ) is free software released under the terms of the GNU GPL as free software with source code. Due to the modular structure of the program and the availability of the source code your own extensions can be incorporated and used. Thus, several 2D and 3D continuum elements have been developed for special cases (for example, anisotropic shell element ) of users.
- Z88Aurora (current version 2a) Freeware, the source code is not disclosed.

Both versions include 24 different element types, including 2D elements ( truss, beam, plate, shaft, torus ) and the 3D elements ( truss, beam, linear and quadratic tetrahedral and hexahedral ). At Z88 include a direct and multiple iterative solver, Z88Aurora additionally has a multiprocessor capable sparse solver. The software has a Windows user interface with context-sensitive online help. The import of Cosmos, Ansys and Nastran files from Pro / ENGINEER (Option Pro / Mechanica ) is the same as the import of Abaqus files possible ( in Z88Aurora ). Manuals show how to deal with Z88 and Z88Aurora examples.

### Additional features in Z88Aurora

Unlike Z88 stationary heat conduction, natural oscillations and geometric nonlinearities are possible in addition to Z88Aurora static linear mechanical strength analyzes. STL and STEP files can be loaded via the geometry library Open CASCADE and discretized by means of two integrated Freeware crosslinker. With a search algorithm can be applied without the need for defining the area of the CAD program on the discretized geometry constraints and material assignments. Studies on the ease of use with respect to the user group found since 2011 by the workflow support tool SPIDER influence into the software. In the current version of Z88Aurora ( V2a ) is also a boundary condition beschleunigeter installation for all solvers, as well as an accelerated version of the direct linear equation solvers have been integrated alongside a parallelization of iterative linear equation solver. Furthermore, it is now able to export the results of individual sets in the post-processor for an external analysis.

- Pictures of the freeware Z88Aurora and the open source software Z88 V14

Workflow | Workflow representation of Preprozessings the single cylinder crankshaft

Postprocessor | post processor using the example of a plastic worm gear

Snapshot Open Source Program Z88 V14

Postprocessor Z88 V14

## Use in research and teaching

Since 1998 Z88 serves as part of the lecture at the University of Bayreuth, the education of engineering students. Due to the possible manual entry of the structure and boundary condition data sets as well as load it illustrates students with the operation of a finite element program. Due to the open file sources, the software can be used for research purposes in the FE sector and modified accordingly.

Among other Z88 in the context of teaching and research at the HS Ravensburg- Weingarten, University of Ioannina, Penn State University, Universidad de Buenos Aires, the University of Cagliari, the University of Maribor, and inserted at the Zonguldak Karaelmas Üniversitesi. In the context of graduate and seminar papers Z88 was previously used, among others, at the universities of Darmstadt, Hamburg- Harburg, Munich, Karlsruhe, Bern and Beijing.

In addition to classroom lectures will Z88 in two textbooks of engineering application. The book Finite Element Analysis for Engineers: An easy to understand introduction has been sold more than 6,000 times. This textbook is aimed at newcomers to the finite element analysis and used Z88, so that the reader can understand all the examples given in the book on your own computer. In textbook Machine Elements - function, design and calculation of Decker (previously 18 runs) is taught the calculation of machine elements with the finite element analysis based on practical applications with Z88.

## Industrial use

Through the open-source approach, many applications rely on Z88 solver, plot outputs and the like. Among other things, Z88 extended on glass plates in building construction for a program for the calculation of point and line -shaped loads. For the determination of elastic moduli and flexural strengths of wood routines were implemented and developed a subroutine in Z88 for the calculation of pressure vessels. Z88 is used by, among others,

- Boeing Missile Defense Systems (USA),
- Teledyne Brown Engineering (USA),
- Winimac Coil Spring, Inc. ( USA),
- Double D Design Ltd.. (New Zealand),
- RINGSPANN GmbH ( Germany ), and
- KTR GmbH ( Germany )

Be used.

Due to the availability of the program code and thus the comprehensibility of the algorithms and material models used repeatedly served as a comparison Z88 calculation program for commercial tools such as NASTRAN and ABAQUS.