FEMtools™ Application Framework

Overview

FEMtools Framework (FtF) is a multi-functional interactive environment for advanced engineering application development, integration, automation and customization. The framework includes utility tools like data interfaces, database management utilities, parameter and response management, state-of-the-art data visualization, a scripting language and API function library.  

Additionally, FtF includes a standard finite element library, linear static, real and complex modes solver, frequency and harmonic response analysis. Alternatively, standard external solvers like MSC Nastran, ANSYS, I-DEAS or in-house solvers can easily be integrated and piloted as part of larger analysis processes.

This open and flexible CAE application development platform is used by analysts to integrate their tools, and create applications that meet the specific requirements of an industry. A unique capability of FEMtools Framework is the integration of data resulting from experimental static or dynamic testing.

FEMtools Framework is used by Dynamic Design Solutions for the development of its test-analysis integration tools to validate, update and refine finite element models. A growing number of developer partners are working on integrating their existing tools or developing entirely new tools that exploit the framework infrastructure and re-usable components. This is a more efficient approach than developing new applications from the ground-up. Some examples of current development projects by partners are integration of acoustics solvers, modal analysis tools, substructure synthesis, and vibration-based material identification.

Key Features

• Convert finite element and test data into a uniform, structured relational database
• Analyze, visualize, manage and report your engineering simulation and test data
• Solve static and dynamic FEA problems using built-in solvers or by piloting standard commercial FEA solvers.
• Use FEMtools Script with hundreds of built-in math and API functions to create your own functions and programs.
• Design of customized user interfaces (GUI)

Applications

FEMtools Application Framework is a software-neutral CAE application development tool mainly used for developing applications that exploit hybrid test and analysis databases. It provides the foundation for all FEMtools products and for products developed by independent partners.

As a stand-alone tool, it can be used as a utility software for simulation and test database management, data translation, data transformation and mesh viewing. 

• Data transformations - normalization, expansion, reduction,...
• Pre- and post-processing of CAE and test data
• Programming applications using FE and/or test data
• Data Translation - Convert FE mesh, FEA results or test data files from one format to another.
• CAE Integration - Software-neutral, customized static, normal modes and dynamic analysis. Import a finite element mesh and use FEMtools' element library to compute element matrices. Then use a FEMtools solver or an external solver to compute the response or eigenmodes of the model.

Benefits

• Faster and more efficient development
• Re-use of standard components like graphics viewers
• Customized user interfaces
• Integration of separate tools in a single custom application
• Software-neutral integration with virtually any FEA package
• Integration with virtually all types of test data 
• hardware and OS platform independent architecture

Standard Components

Direct Data Interfaces

FEMtools Application Framework is an open program that can be naturally integrated in an existing CAE environment. Two-directional translators are available with the most popular FEA and test database formats (NASTRAN, ANSYS, I-DEAS , ABAQUS, Universal File, …) and with other commercial software like MS Excel, and MATLAB. These translators are direct and are integrated with no limitation of FE model size. New interfaces can easily be developed using the FEMtools scripting language.

The ability to communicate with external databases serves several specific purposes, like for example:

• Converting finite element mesh data between different formats.
• Pre- and post-processing of FEA and test data.
• Interfacing with an experimental database in order to compare FEA data with test data.
• CAE Integration.

Database Management

Interface programs import external databases into a relational database of tables. FEMtools Application Framework provides a number of utilities for interactive definition, editing and transformation of all data in the internal database:

• Spreadsheet-style table editing
• Transformation of coordinate systems
• Support of local rectangular, cylindrical or spherical coordinate systems
• FE model reduction (Guyan, IRS,…)
• Mode shape normalization, scaling, truncation and expansion (mode mixing, modal coordinates method, dynamic expansion method, SEREP method,...)
• Interactive picking of sets of elements and nodes or automatic creation based on topology, material or geometry
• Boolean operations on sets
• Verification of FEA database integrity

Parameter and Response Management

FEMtools Application Framework provides commands and functions for definition of parameters and responses. Parameters are physical element properties that can be used as variables for sensitivity analysis, design optimization or model updating applications. The definition can be based on the existing property cards, for example the common material property of a set of elements. Alternatively, element sets can be defined by filters, graphical picking or Boolean operators. FEMtools manages the property cards and removes the hassle of manually creating new property cards as new element set are created. 

Data Visualization

Data is visualized using interactive 2D and 3D graphics. Functions, tables, and vector results are visualized in curve, matrix and mesh plots. OpenGL graphics offers quality graphic performance that you have come to expect from the newest generation of engineering workstations:

• Multiple simultaneous graphics windows
• Dynamic viewing (rotation, pan and zoom)
• OpenGL graphics rendering
• Color-coded and vector-coded displays
• Animated, side-by-side and overlay plots
• Export of animated shapes as AVI files
• Export graphics in Postscript or bitmap files
• Graphical picking of nodes and elements

Animated shapes can be saved as AVI files (on Windows) or a series of bitmap files (on Unix and Windows). AVI files can be directly imported in presentation or reporting software.

FEMtools Script Language

FEMtools Script is the integrated FEMtools programming language that is designed with the needs of the FEA analyst in mind. The language offers many advanced features but is based on a easy to learn standard syntax (Basic).

There are hundreds of built-in math and FEMtools API functions that provide direct access to the FEMtools database and the FEMtools database and analysis tools. 

The FEMtools menu interface can be customized to provided access to your own functions and commands. FEMtools Script makes FEA scripting easy and fun so you can focus on your solution.

Features:

• Integrated script editor window - FEMtools scripts can be edited and run from an integrated editor window, with color-coding of commands, functions, statements, etc. This facilitates development and debugging of scripts. Scripts can be compiled and run directly from the Script Editor.
• Mathematical programming - Advanced functions for mathematical programming, array operators, complex numbers, ...)
• Support of sparse matrices
• Regular expressions
• User interface programming
• OLE automation/ActiveX
• Compiled execution
• Error checking
• Online documentation - Access to all function documentation from the online FEMtools help feature. Example program code can be pasted directly into your own FEMtools Script program.

Support of sparse matrices

Many finite element-based applications involve the use of sparse matrices i.e. banded and sparsely populated matrices. The memory requirements of programs can therefore be seriously reduced by storing only the non-zero elements of these matrices and perform matrix operations directly on the sparse matrix. FEMtools includes the functions to define, delete and work with sparse matrices.

Support of regular expressions

To facilitate string and table parsing, several functions like Match, Replace, Search, and Split are available with support for complex regular expressions. 

Functions for OLE automation

FEMtools Script programmers can take advantage of the power of OLE automation to extend the capabilities of an application on Microsoft Windows platforms. There are many potential applications for using OLE automation servers. Just imagine how you could integrate with, for example, Microsoft Office applications to use Word as a report writer, use PowerPoint to make presentations of you results or use Excel to post-process FEMtools tables as spreadsheets.

You can also extend the math programming functions of FEMtools Script by making use of the extensive library of math and graphics functions that are provided by general purpose programming environments like MATLAB and its many specialized toolboxes. By exploiting the MATLAB object model you can use all MATLAB functions from within FEMtools Script programs.

There is a growing number of  finite element programs that have been rewritten for the Windows operating system and support an object model. Data interfaces between FEMtools and these FEA solvers could be based on OLE automation.

By using OLE automation, you can seamlessly integrate external tools with your FEMtools Script programs without the user knowing that you are actually using for example Microsoft Word or MATLAB. This possibility holds a tremendous potential to increase the power, efficiency, speed and user-friendliness of your applications.

FEMtools API Function Libraries

• 240+ FEMtools API functions for database access, analysis, process control, user interface programming, and  licensing.
• Functions for launching and controlling external tools with ActiveX/OLE automation technology under Windows.
• Access to all components available in the different FEMtools modules (e.g. direct data interfaces, graphics, correlation analysis tools, sensitivity analysis,...).

Interactive User Interface

FEMtools is operated via a customizable menu interface, the FEMtools command language and FEMtools scripting. The menu interface is attractive if you are a new or occasional user, if you need to edit tables or display graphics. You can browse through the different menus to get a overview of the features and easily experiment with different commands. The FEMtools command language is for more experienced users who prefer to type commands in the entry field of the console window. This mode is often the fastest way to complete standard procedures, or run your own scripts. Once a procedure becomes more complex, needs to be developed or repeated often with only small changes, using FEMtools scripting language is the most suitable approach.

For report generation, users of the Windows version can take advantage of the Copy and Paste features to transfer text and graphics between FEMtools and other applications like Word or Excel via the Windows Clipboard.

A user often wants to repeat the GUI menu and dialog box actions on another database, or just keep track of all the action required to reach his goal. FEMtools records all actions in a journal file that can then be edited and re-used as a command script.

Integrated Finite Element Analysis 

Static and Normal Modes Analysis

If the FEMtools database contains the complete FE model description, the user can import externally computed mass and stiffness matrices, static displacement, normal modes, complex modes or operational shapes. Alternatively, the built-in element library and solvers can be used. Piloting external standard solvers like MSC.Nastran and ANSYS is completely automated using scripts.

Frequency and Harmonic Response Analysis

FEMtools can synthesize FRFs between any combination of degrees of freedom of the FE model from analytical or test modes. Operational displacements, velocities and accelerations for harmonic nodal and pressure loads can be computed using viscous, structural or modal damping.

Synthesis of FRFs from test mode shapes

Test mode shapes are extracted from experimentally obtained Frequency Response Functions (FRF) using modal parameter extraction methods available in several third party test software. It is possible to re-synthesize the test FRFs from the extracted test mode shapes and compare this result with the original measurements.

Re-synthesizing test FRFs is a way of smoothing the measurements and verifying the modal extraction. It is also recommended to use smoothed FRFs for FRF-based correlation and model updating purposes.

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Last modified: December 20, 2006