ISOMAG - Computer Aided Vibration Isolation of Machines and Devices
On behalf of the Federal Institute for Occupational Safety and Health (BAuA) the ITI Gesellschaft für ingenieurtechnische Informationsverarbeitung mbH Dresden / Germany has developed the Version 1.2 of the program ISOMAG for computer-aided design and dimensioning of the vibration isolation.
The new features in version 1.2 are:
- Variable frequency range and time domain
- Excitation with halfsine pulses
- User-definable excitation (pointwise F(t))
- Ground excitation also as pointwise a(t), v(t), s(t) (earthquake excitation)
- Simultaneous output of results in one result window
- Bugfixes of known errors in Version 1.1.
ISOMAG 1.2 is a user-friendly, self-explaining program for calculation and design of the vibration isolation based on a rigid-body-model. The double vibration isolation and the dynamic characteristics of the environment can be calculated. The program operation, model description as well as the data in- and output take place graphic-interactively. Implemented wizards help the operator. ISOMAG 1.2. is an advancement of ISOMAG 1.1.
The research report Fb 1014 "ISOMAG 1.2 - Extension and Improvements / Erweiterungen und Verbesserungen" (see link on the right, there you'll find also the distributor) only contains the installation-CD. The CD also contains the description of the new features respectively version 1.1 as PDF-file. New user should buy the research report Fb 944 "ISOMAG 1.1" (see link on the right) with the complete description of the program too. The program is designed for MS-Windows NT (SP 4) and runs under MS-Windows 98 / Me / 2000 / XP. An integrated MS-Access-database contains the parameters of more than 3000 isolators. An actual version of the database (status: January 2004) you can download here.
The language of the program can be changed from German to English and vice versa. The program desktop with an simple example is shown in the following figure. The machine can be composed of several various rigid merged bodies. The bodies are created by an simple mouse-click at the desktop. Possible excitations are harmonic force, single impulse, impulse series, imbalance and user-defined pointwise F(t). The ground excitation may be harmonic or impulse or user-defined a(t), v(t), s(t). All existing excitations are phase-correctly overlaid. Vibration insulators and their parameters can be read from a database with more than 3000 elements from various manufacturers. Static and dynamic stiffness are considered. The damping of the isolators is also included. Global approach for steel- or rubber-elements can be used, in addition known values can be entered. Thereby the validity of the theory of small damping is supposed.
The environment can be rigid or may have elastic properties, the program calculates the properties for beams and plates with various boundary conditions and materials. The input of measured natural frequencies e.g. of a ribbed plate is also possible. The position of the machine relative to the environment is approximately regarded. All results are calculated always in all degrees of freedom, so it isn't necessary to simplify the model as before.
All elements of the model can be free positioned and can be interactively or numerically defined shifted or twisted. Elements may be selected in the model window or in the project tree. The project tree allows a fast supervising over the model and a correct selecting of small or hidden elements. Changing the colours of the elements is helpful for a good representation. Additionally the elements can be viewed solid, transparent, as wireframe or invisible. Model can be represented in four windows (three technical views and one 3D view) or in one window at a free selectable view. The operator can fix dimension lines interactively at the edge of bodies, so dimensioned drafts can be shown in the printed results.
Results are first natural frequencies and natural forms, which may be shown in an animation. Static and dynamic loads of single isolators as well as the whole environment can be calculated. Defined load- and displacement-limits of the isolators are supervised. Time solution, frequency response function and transfer function for user-defined points and isolators can be graphically represented (see next figure). Spectra and/or transfer functions can be calculated from given time solutions. Displacement, velocity and acceleration at given points can be calculated.
An advantage of the program are the integrated wizards. After the definition and parameterisation of the bodies (masses and inertia moments) and layout of the isolators the wizards can calculate and optimize the isolation. Based on a defined target-degree-of-isolation, the program generates editable terms. With this terms the user can choose suitable spring-elements from the integrated database. If the defined degree of isolation can't be reached with single vibration isolation, a second wizard for double vibration isolation generates a intermediate foundation with dedicated dimensions and selects isolators with suitable properties from the database. Outside of the program the database (MS Access97) can be completed with user-defined isolators.
All results are updated after every change of the model, so are the effects of changing position or parameters of elements are immediately visible. A very helpful feature is, that some results (time solutions, transfer functions etc.) can be 'frozen', they would not be changed in future by changing the model.
A lot of aids like duplicating or alignment of elements or graphic-interactively twisting or moving of views allows a comfortable work. Size and number of windows can be changed, a standard view can be restored with one click. Static undefined models or transgression of limits are shown.
A downstream print program (Print Designer) outputs the results. It generates a report with all essential information and wanted results, including pictures of the model and of the graphic results (time solutions etc.). The report is editable, self-defined text, figures or objects can be added.
The program ISOMAG for design and calculation of the vibration isolation allows a fast and efficient work. The graphic desktop and the integrated wizards and checkups lead to a efficient solution. By using of ISOMAG the vibration isolation of machines and devices can be computed and optimised fast and cost-effective.