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What's New

April 2010 - FEMtools 3.4.1 Maintenance Release

Dynamic Design Solutions announces the release of FEMtools 3.4.1. This maintenance release provides important upgrades to the interface programs and contains various other minor corrections and extensions to commands and API functions.

Customers with current support and maintenance can find more information on this release and how to download the installation packs in the FEMtools Support site. A login name and password is required to access the support pages. If you have a current Maintenance and Support contract and did not yet receive a login name and password, then register at http://www.femtools.com/support.htm or send a request to support@femtools.com

License files for FEMtools v3.4.0 remain valid for v3.4.1.

10 February 2010 - Launch of Japanese FEMtools Website

Dynamic Design Solutions (DDS), in collaboration with Structural Science Inc. (SSI), the FEMtools Solutions Partner for Japan, announces the launch of its FEMtools product website in Japanese language.

The new web site will provide visitors from Japan with up to date product information and news as well as access to the FEMtools support site.

See www.femtools.jp

January 2010 - Structural Science Inc. (SSI) is the New Main FEMtools Solutions Partner in Japan

Structural Science Inc. (SSI) has become the new main FEMtools Solutions Partner in Japan from January 1, 2010. SSI will provide sales and marketing of FEMtools, and technical support and maintenance services.

SSI replaces Software Express Inc. (SOEX) after the retirement of its General Manager, Mr. Oda. SOEX has served as the FEMtools Solutions Partner in Japan for more than 10 years, and successfully introduced FEMtools to Japanese companies. This company also translated most FEMtools manuals to Japanese language.

SSI already provided technical support services to several of our customers and has gained a strong knowledge of the FEMtools software. From now SSI will also become responsible for sales and marketing of FEMtools in Japan and support all Japanese customers with a new staff. During the transition phase, SOEX will continue to collaborate with SSI to guarantee a smooth transition.

Email: support@ssinst.com
http://www.ssinst.com

January 2010 - Free Online Tutorial on Using Reprise License Manager

Starting in February 2010, Reprise Software is launching a quarterly series of on-line tutorials designed to help FEMtools users get more value out of the Reprise License Manager (RLM). You can register for these free 1-hour sessions by sending an email to Reprise Software

The sessions will be conducted by Bob Mearns, lead RLM software developer who has over 15 years experience developing and supporting software license managers.

The first session is scheduled for the 10th of February at 11AM EST.

It will focus on:

- Basic RLM Server Setup
- How and where RLM looks for licenses
- Using the RLM Web Server Admin Interface
- A systematic approach to diagnosing license server connectivity problems

Space is very limited so register now.

The recorded webinars will be available for replay from the Reprise Software website.

December 2009 - Plan Ahead: 2010 DDS Technology Course Program

Registrations are now accepted for our technology courses in 2010.

The course on Model Verification, Validation and Updating Technology will be organized for the 6th year in a row and will take place on May 5-7, 2010.

After two successful editions, the course on Structural Optimization Technology will be presented again on October 20-22, 2010.

All courses are presented in English and take place in Leuven, Belgium. As usual, FEMtools will be used for hands-on exercises during approximately half of the time.

Additional courses may be organized at different locations in collaboration with FEMtools Solutions Partners. For more information and registration form, see http://www.femtools.com/courses

November 2009: NAFEMS and ASME Share Forces to Promote Verification and Validation Concepts (V&V)

For many of our customers, FEMtools has become their reference tool for validating and updating FE models, especially for applications in structural dynamics simulation. For many years, however, the concepts of model verification and validation remained the domain of visionaries with no formal definitions and processes available. Recently, major engineering organizations and societies have taken initiatives to publish sustaining documents (what is, why do, or how to guides) that ultimately could become formal standards or best practices books for different engineering disciplines.

NAFEMS and ASME (American Society of Mechanics Engineers) recently cooperated to produce a leaflet entitled "What is V&V?" The attractive tri-fold color flyer is intended to be an "eye catcher" that will be freely distributed at NAFEMS and ASME events. In addition to being a pocket sized introduction to Verification and Validation, the leaflet points to the work of the NAFEMS Analysis Management Working Group (AMWG) and the ASME V&V-10 Computational Solid Mechanics standards group, just two groups contributing to the ever increasingly popular and important areas of verification and validation in computational mechanics.

The leaflet can be downloaded from the NAFEMS website (download). ASME has published a booklet entitled "Guide for Verification and Validation in Computational Solid Mechanics (ASME V&V 10-2006)" that can be purchased from their website (www.asme.org).

DDS is a member of NAFEMS and the Analysis Management Working Group (AMWG).

November 2009: Mapping Laser Scanning Measurements on a FE Mesh

Laser vibrometry or electronic holography can be used to obtain vibration modes which in turn can be correlated with finite element results. Each experimental mode shape will typically be presented as a dense cloud of scanning points with each point moving in the direction of the laser or camera. Analyzing the correlation of these vibration modes with a finite element model poses some specific problems with respect to mapping the scanned surface onto FE model, identifying and extracting the corresponding translation degrees of freedom, averaging for measurement noise and computing numerical correlation criteria.

DDS has recently developed a custom solution for postprocessing a set of data files containing measured vibration modes with an ANSYS finite element model of a turbine blade. Written in FEMtools Script, this solution automates the entire work flow and reporting of results. It can be integrated into the FEMtools menus or operated in batch mode for processing large quantities of data or as part of an integrated quality inspection system.

For more information, contact support@femtools.com

October 2009 - FEMtools 3.4 Released!

Dynamic Design Solutions announces the release of FEMtools 3.4. This major release introduces new functionality for meshing, model updating and structural optimization in addition to numerous improvements and extensions to existing tools. Some of the highlights of this version are the following:

Mesh Generation Function Library

A function library is added to generate surface and volume meshes from a definition of the geometry (vertex, curve, surface). Unstructured surface meshes can be generated for generic surface patches and volume meshes are obtained from 2D meshes with operations like extrusion and revolving. This new FEMtools API function library complements the already available lattice-based mesh deformation ('morphing') and provides the functionality to mesh very complex geometries. It can be used for applications like parametric meshing for shape optimization, meshing design spaces for topology optimization or to implement mesh coarsening and refinement tools.

Mesh Quality

Functions to verify the quality of imported or generated finite element meshes are now included. Quality metrics like aspect ratio, convexity, taper, warp angle and others can be computed on the fly and visualized with color-coded mesh graphics. Results can be further post-processed by computing histograms or sorting mesh quality values. Additional mesh quality metrics can be implemented using the FEMtools Script programming language.

Rigid Body Properties Extraction (RBPE) From FRF Measurements

This new add-on tool is used to obtain the mass (M), center of gravity (CoG) and mass moments of inertia (MoI) from the low-frequency portion of measured accelerances (FRFs). These properties can be used as targets for finite element model updating, or to reduce components to lumped masses for model reduction in structural dynamics simulations or motion analysis.

ODS-based Model Updating

Experimentally obtained vibration shapes (Operational Deflection Shapes or ODS) can now be used to update stiffness, mass and damping parameters if information is available on the dynamic excitation forces. These forces can be measured themselves, for example as forcing displacements, velocities or accelerations and are applied to the finite element model. From the differences between simulated and experimentally-obtained ODS, conclusions can be drawn on required adjustments of stiffness, mass and damping. This new functionality is completely integrated within FEMtools Model Updating and can complement other updating types like using mode shapes or FRFs as reference responses. An important application of ODS-based model updating is monitoring of vibrating machinery for damage and structural health.

Postprocessing of Local Model Updating Results

By using efficient data management and powerful algorithms for sensitivities and model updating, FEMtools can handle very large numbers of updating parameters. Model updating using local element parameters like thickness or elastic modulus may result in a large number of updated properties that can vary from element to element. This is a standard strategy for explorative model updating to obtain information on local changes that may be required. Results must be interpreted in terms of changes that may be required to geometric refinement or mesh density. Such updated models, however, are not suitable for further analysis due to the large number of property cards in the finite element model. New postprocessing tools are now available to regroup elements based on their properties into a lower and practical number.

Structural Optimization using DOE/RSM

Design of Experiments (DOE) and Response Surface Modeling (RSM) was already available in FEMtools 3.3 for applications in model updating. In FEMtools 3.4 these methods have now been integrated in FEMtools Optimization and can be used with generic optimization parameters, objective functions and constraint equations. Design of experiment (DOE) techniques aim at sampling the design space of a problem in an efficient way. The main goal of DOE is to obtain the required information with a minimum number of sampling points, as the evaluation of each sampling point requires an additional run of the FE-model. FEMtools provides the following designs: factorial designs, central composite designs, Latin hypercube designs, D-optimal designs, and user-defined designs. Response Surface Modeling (RSM) is used to build an approximate model to predict the response of the system in function of the design parameters. This approximate model can then be used to optimize the response of the considered system instead of the finite element model of which it was derived.

Ready for Windows 7

FEMtools 3.4 supports the newest Microsoft Windows 7 operating systems in native 32-bit and 64-bit versions.

See the FEMtools 3.4 Release Notes for complete information on this release.

FEMtools 3.4 is available as a free upgrade to all customers with current maintenance and technical support contract. The installation packs for all supported OS can be downloaded from the FEMtools Support website. A new license file is required to run FEMtools 3.4.

Contact support@femtools.com for more information on this release and to obtain your support website login password and a new license in case you have not yet received these.

July 2009 - Ogden Material Identification using FEMtools Optimization

The Ogden material model is frequently used in finite element programs to simulate the behavior of non-linear elastomers. The values of the material parameters of the Ogden model are highly material dependent. The main challenge in using the Ogden model in finite element simulations, is to find reliable estimates for the values of the Ogden material parameters. The relation between an imposed displacement and the resulting reaction force can be used to identify these material parameters using a mixed numerical-experimental approach. In this approach, the objective is to fit the simulated reaction force curve onto the measured reaction force curve. The computationally most efficient way of doing that is by using a gradient-based optimization strategy.

Such identification routine was implemented using FEMtools Script for the process identification part, FEMtools Optimization for the optimizer routines, and used MSC.Marc to compute the reaction force curves.

More information can be found in the following application note:

Identification of Ogden Material Parameters using FEMtools, Download (PDF, 433 KB)

June 2009 - Dynamic Design Solutions to Present a Course on Model Updating at OMAC II Workshop

Dynamic Design Solutions invites you to attend the upcoming OMAC II workshop September 24-25, 2009 in Aalborg, Denmark. This two-days event is relevant for engineers and researchers working within the area of Operational Modal Analysis. You will learn to setup your tests, perform and validate your measurements, analyze your data and validate your results. In addition, you can get extensive training on finite element model correlation and updating using results obtained from Operational Modal Analysis.

Please click here to view a PDF file with the OMAC invitation.

OMAC II is organized by:

May 2009 - DDS Participated in Workshop on Structural Safety Assessment of Tall Buildings in UAE

On May 11, 2009, Dynamic Design Solutions co-organized a seminar on "Smart Building Technology - Structural & Seismic Safety" that was held in Abu Dhabi, UAE. The goal of the seminar was to present current technologies for seismic response analysis and structural health monitoring of tall buildings. This seminar coincided with the start of a 3-years study that is meant to analyze the building structures throughout the Abu Dhabi emirate and make sure they would be able to cope with a serious tremor. Like other cities in the region, new development projects in Abu Dhabi include an increasing number of tall buildings that will have to be earthquake-resistant.

Dynamic Design Solutions' CEO Eddy Dascotte presented a paper entitled "Evaluation of Structural Safety by Combining Computational Models and Test Data". The speech included a live demo of a random vibration test using a mockup of a 3D frame structure and a four-channel acceleration data acquisition system. Using operational modal analysis integrated with FEMtools Model Updating, it was demonstrated that a reduction of joint stiffness at the base of the frame structure could be identified by shifting resonance frequencies and differences in the mode shapes.

For more information or a copy of the presentation, contact info@femtools.com.

March 2009 - Estimating Rigid Body Properties from FRF Measurements: A New FEMtools Add-On Tool

Dynamic Design Solutions announces the upcoming release of FEMtools Rigid Body Properties Extractor, a new tool to obtain the mass (M), center of gravity (CoG) and mass moments of inertia (MoI) from the low-frequency portion of measured accelerances (FRFs). These properties are useful to serve as targets references in updating the finite element model of the tested structure, or to reduce components to lumped masses for model reduction in structural dynamics simulations or motion analysis.

Obtaining the rigid body properties is done in 2 steps. First, the rigid body responses (called "mass lines") must be extracted from the FRFs. The mass line corresponds to the value of the flat part of the response located between the low-frequency suspension modes and the elastic modes. These values are obtained by using a least squares fit of a low order polynomial (e.g. quadratic approximation). Once the mass line values are known, then the rigid body mass properties are obtained in the second step by solving a set of algebraic equations.

Experimental data are imported from a Universal File (UF) or other. The FRFs must satisfy some requirements with respect to the measurement configuration (acceleration/force obtained from a freely suspended structure), and the number and positioning of excitation and response locations. If these conditions can be satisfied, then the proposed method presents a low-cost and fast alternative to traditional pendulum techniques.

FEMtools Rigid Body Properties Extractor Control Panel (click to enlarge).�

The FEMtools Rigid Body Properties Extractor comes as an add-on to any FEMtools configuration. It is an interactive tool that allows the user to display the FRFs, define a frequency band between the suspension modes and elastic modes, and analyze the mass line values. An inertia box visualizes the equivalent mass volume with animation of rigid body modes. The rigid body properties (M, CoG and MoI) are displayed in real-time using tabular format with several error estimates. They can be exported for use in other programs or be used as updating targets in FEMtools Model Updating.

This new exciting add-on is now available for beta evaluation. For more information and to request an evaluation copy, contact info@femtools.com

February 2009 - Integration of Dynamics Simulation, Model Validation, Updating and Optimization at Faurecia

The Exhaust System Division of Faurecia, a long-time FEMtools customer, and Dynamic Design Solutions recently presented an optimization approach for tailoring the dynamic response of a complete exhaust system using finite element modeling.

Before the optimization procedure is started, the FE model is updated using modal test data to ensure the validity of the FE model and to identify damping characteristic. The subsequent optimization is performed to keep the force transmitted by the exhaust system through the isolators to the car body below the design specifications, optimizing the stiffness of the decoupling elements. The goal is to ensure a good NVH (Noise Vibration Harshness) performance of the exhaust system.

To ensure a computationally efficient process, Dynamic Design Solutions implemented an optimization routine that consists of two iteration loops: an inner and an outer loop. The inner iteration loop performs the optimization using a fast modal domain modification technique to predict the change of the dynamic response of the structure. However, the modal domain prediction is only accurate within a limited parameter range. Therefore, the outer iteration loop re-evaluates the full finite element model once the parameter changes exceed the �??trust-region�?? bounds of the modal domain prediction. The solution of the full re-evaluation is then used as an improved base for the modal domain prediction in the inner iteration loop.

This project involved the use of FEMtools Model Updating and the new nonlinear optimizer of FEMtools Optimization. The custom optimization routine was developed with FEMtools Script.

For more information, see the following paper or contact info@femtools.com

T. Lauwagie, J. Strobbe, E. Dascotte, J. Clavier, M. Monteagudo, Optimization of the Dynamic Response of a Complete Exhaust System, presented at the 27th International Modal Analysis Conference (IMAC), February 2009, Orlando, Florida, USA. (Download (PDF, 1.0 MB)

February 2009 - Automotive Companies Standardize on FEMtools for FE Model Validation and Updating

Several well-known automotive companies have joined the ranks of FEMtools users in the past year. They include major car makers as well as component suppliers.

Renault (Paris, France) has deployed several licenses of FEMtools Model Updating to be used by engineers at its Paris technical centers in Rueil-Malmaison and Guyancourt. The successful European car maker now standardizes on FEMtools for its test-FE analysis correlation and FE model updating projects that include engine and chassis development. This decision for company-wide deployment was taken after using pilot licenses at some departments for several years and after an intensive evaluation by the IT group. FEMtools will replace a legacy software that was in use at Renault for many years but did no longer satisfy current requirements.

Other global car makers that actively use FEMtools are Ford Motor Corp. (USA) and Honda (Japan).

Companies that develop and manufacture components and subsystems like engines, brakes, exhaust systems, suspensions, seats etc. also make active use of FEMtools for simulation, model validation, model updating and structural optimization. In most cases FEMtools is used by the NVH (Noise, Vibration, Harshness) groups. The following are some references of companies that use FEMtools for these purposes: BorgWarner Turbo Systems, Faurecia, Valeo, Tenneco, Magna Powertrain, Johnson Controls, MAN B&W Diesel, and AP Brakes.

January 2009 - Dynamic Design Solutions Celebrates 15th Year!

Dynamic Design Solutions is proudly celebrating its 15 years in business as an independent and employee-owned CAE software development company. We thank all our customers, partners and friends that have contributed to realizing our vision of a company that initially focused exclusively on researching and developing practical and easy-to-use software for validation and updating of finite element models. This field has long been, and still is, a niche that sits between the fast growing ranks of analysts and the conservative world of experimentalists. It has been an interesting challenge to find the formula for solutions that satisfy a very wide array of needs.

During the past period we have succeeded to evolve from a pioneering start-up company to become the technology leader with a prestigious and wide customer base of commercial and academic organizations worldwide. Today, with our technology matured and most barriers for wide deployment removed, Dynamic Design Solutions is ready to engage in new ventures that will embed model updating as the enabling technology in new applications, such as material identification and structural health monitoring. Recently we have also begun to expand into structural optimization. This is an exciting field that we found to be a perfect complement to model updating and that we are approaching with the same enthusiasm. Stay with us, to be continued...

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