Frequently Asked Questions


 Updated 8 May 2008


Before you purchase

·        Why should I consider buying the ICATS software?

ICATS software is the result of 30 years of research in Structural Dynamics, about 30 PhD theses and a large number consultancy jobs for industry. We cater both for the beginner (we use it in our short courses and other teaching activities) and for the expert (we use it ourselves).

 

·        When was your last price increase?
January 1990! We aim at keeping the pricing of the software and of the updates at the same level for the foreseeable future.

 

·        Are there discounts for educational establishments?

We give 50% discount to educational establishments if they use the     MODENT software for teaching and research only.

 

·        If the software is bought with an educational license, can it be used for commercial work?

It can be if the total invoice to the client is less than £5,000/year. If it exceeds that, a small royalty, agreed in advance, will become payable.

 

·        What exactly do I need to buy ?
 Our basic package, consisting of MODENT, MODESH, MESHGEN, MODPLAN and UTILITY programs will be sufficient for most of your needs. The finite element program FINES, which has some specialized features, is a powerful tool without the over-complication of large FE analysis codes. We do not have a complicated pricing structure with several add-ons. You can also buy MODIFY for advanced structural coupling.

 

·        I think I have a need for modal testing but I do not know where to start from. What is your advice?

We would recommend the following textbook by D. J. Ewins: Modal Testing & Analysis: Theory & Applications, Research Studies Press, London. 

 

·          How about buying equipment and software?

As a turnkey system, we would recommend our Portable Modal Testing and Analysis System. It is an integrated hardware/software package that enables vibration testing and analysis within a day of purchasing the system.

 

·        Do I need to use different programs for Windows NT, 2000, XP & Vista?
No. There is only one 32-bit version of each program that runs across all Microsoft operating systems, including 64-bit XP & Vista. We release 64-bit version of the MODENT in 2009.

 

·        Are the programs copy-protected?
Yes. You can either opt for a hardware key, or a software key that checks actual hardware details such as hard disk serial no, Ethernet card serial no and IP address.

 

·        I need to have several copies on the same site. Do I get a discount?
Yes. We have multi-copy discount structure for both industrial sites and for educational establishments. See our price list.

 

·        Is there a Unix version ?
No. We think that the Unix machines and operating systems are too fragmented to provide the level of support we can provide on the PC platform. However, we have plans for a Linux version.

 

·        I already have a modal analysis package and lots of data files. Will I be able to use those with the MODENT Suite?

We support ASCII universal file formats (UFFs) for measured FRFs, geometry definition and mode shapes. Provided your system can export these in this format, our software will be able to read your data. Most modal analysis packages have such an option.

 

·          Which UFF files do you support?
We support 58, 18, 15, 781, 2411, 82, 780, 71 & 2412, ie FRFs, nodes, elements and modes. Local co-ordinate systems are supported.

 

·        I understand that you give discounts to current uses of a recognized modal analysis package. How can I take advantage of such offers?
From time to time, we have promotional offers where we offer up to 50% discount to owners of recognized modal analysis packages. Please use the Quotation/Information Request Form on our Web page.

 

·        What is the difference between program MODIFY and the MODIFY option of in MODESHMODESH?

Program MODIFY is a powerful general-purpose structural coupling program with extensive facilities for complex eigensolutions, damped beams, forced transmission, internal forces, etc. The program will suit advanced industrial and research use.
The MODIFY option in MODESH allows mass, stiffness, damper, vibration absorber modifications provided geometry and modal data are available. This option allows a very quick assessment of possible design changes.

 

·        Do you have a program for finite element model updating?

We have several research codes for model updating but we feel that the technology is not mature enough for such programs to be given to users. Instead, we have decided to focus on correlation and several new techniques are available in MODESH.

 

Portable Modal Test and Analysis System

·        Which data acquisition front ends do you support with your Portable Modal Test and Analysis System?
So far four: SKF Microlog MX, Data Physics ACE/Quattro, HGL Hummingbird and B&K Pulse. We are happy to discuss your requirements and advise accordingly.

 

·        Can I specify my own component (eg accelerometer, hammer or notebook) computer when buying the Portable Modal Test and Analysis System?

Yes. You can specify and/or delete any component of the Portable System. The price will be adjusted accordingly.

 

·        What sort of computer will I get with the Portable Modal Test and Analysis System ?
Difficult question as the IT scene changes so quickly. We offer a high-spec notebook from an established vendor.

 

·        How do I transfer measured frequency response function data from the FFT analyser to the PC?
A utility software is provided for DI. DataPhysics and B&K Pulse save the data in UFF which is read directly by the MODENT Suite.

 

Updates, Support & New Features

·        How do I find out about the new features that are introduced since I purchased the programs quite a while ago?

Have a look at the Development History on our Web site.

 

·        What is your policy for updates and support?
The selling price covers updates and support for one year. A yearly fee of £1,000 (£500 for educational establishments) is payable thereafter if further updates and maintenance is required. We release one major update 18 months. MODENT 2002 was released in June 2002. MODENT 2003 was released in July 2003 and MODENT 2004 in October 2004. MODENT 2006 was released in December 2005. MODENT 2008 was released in March 2008.

 

·        What is the update cost if there is no current maintenance agreement?

The answer depends on when you bought your MODENT Suite? The older it is, the more it will cost to upgrade. Every April, we write to our users, quoting an update price, with and without maintenance agreement. Please contact ICATS for a quotation of use the Quotation/Information Request Form on our Web page.

 

·        Are the data files compatible across versions?
Yes. We have not changed our data file format since Version 1.0 and we have no plans to do so.

 

·        Do you support the Universal File Format (UFF)?
We do for frequency response function, geometry definition and modeshape definition (ASCII format, types 18, 15, 781, 2411, 82, 780, 71 & 2412). More being added as the need arises. To enquire, please use the Quotation/Information Request Form on our Web page.

 

·        Is the MODENT Suite a finished product, or will it be developed it further?
No engineering software with a significant user base ever reaches the status of a finished product because of the diversity of the applications and user feedback. We will continue adding new features and improving the user interface.
 

MODENT

·          What is MODENT?
MODENT is the main modal analysis program that extracts natural frequency, damping and mode shapes values from measured SIMO & MIMO FRF data. It can also generate FRFs from modal data as well as mass/spring/damping matrices. In addition, it can provide Quality Assurance data for modal test results. Finally, it has an extensive set of Mode Indicator Functions (MIFs) that can indicate the number of modes within a given frequency range.

 

·          Why do you have so many modal analysis techniques? Will they give different results?
With perfect FRF data (ie no measurement errors or noise), all parameter extraction methods will give the same answers. However, when the FRF data are polluted by noise the results may be slightly different, or some modes may be missed. In our experience, the selection of a particular type of modal analysis should be done in the light of the characteristics of measured data: well-separated undamped modes, damped close modes, presence of noise, are all important factors. Our User's Guide and Guided Tour give several examples of what to use when.

 

·          What are the unique features in MODENT?

Too many to list. Reciprocal modal vectors to assess the quality of modal analysis, the use of principal response functions to assess the quality of measured data, advanced mode indicator functions are all novel features that result from several decades of cutting-edge research.  

 

·          What about modal analysis features?

Again too many to list. Among unique features are non-linear modal analysis and multi-mode, multi-FRF non-linear least squares fit.

 

·          Does MODENTdo Operational (or Output-only) Modal Analysis (OMA)?

Yes. It has both frequency-domain and time-domain OMA options.

 

 

MODESH

·          What is MODESH? 

MODESH is the main post-processor with FRF overlay, animation, FE/MA correlation and structural modification features.

 

·          Do I need to do modal analysis for operating deflection shape (ODS) analysis?

No. You can animate your (raw) measured FRFs at any frequency by using the ODS option in MODESH.

 

·          Is there a size limit for displaying models?
There are no software-imposed limits. The limits are set by the amount of physical memory and disk swap space.

 

·          How is structural modification performed?
Starting from either measured or predicted modes, ie natural frequencies, damping factors and mode shapes, it is possible to see the effects of adding masses, springs, vibration dampers or mass/stiffness/damping matrices. The output is an overlay of original and modified FRFs.

 

MESHGEN

·        What are the capabilities of MESHGEN?
      MESHGEN has three main functions:

It can generate a measurement mesh using built-in commands

It can generate a finite element mesh for FINES.
It can convert a series of FRF measurements taken in arbitrary local axis systems into a global consistent axis system.

 

·        Can I use any co-ordinate system?

              Yes, any combination of Cartesian, polar and spherical co-ordinates can        be used.

·        Can I use both local and global co-ordinate systems?

              Yes, any combination of global and local co-ordinate systems can be used.

 

MODPLAN

·        What is MODPLAN?
MODPLAN is the vibration test planning module. It provides guidance for the selection of suspension, excitation and measurement points.

 

·          What do I need to be able to use program MODPLAN?
You need a finite element model of the structure you want to test. Program FINES can be used for this purpose.
  

FINES

·        What is FINES?
FINES is the finite element module of the MODENT Suite programs. It has an extensive 2D & 3D element library and supports complex eigensolutions.

 

·        What are the advantages of FINES?
FINES is a very compact FE program and the data preparation through MESHGEN is very straightforward. It is ideal for the FE analysis of relatively simple structures without the overheads associated with multi-purpose FE programs.

 

UTILITY PROGRAMS

·        Why do you have utility programs?
Some facilities, such as UFF data file conversions or FE interfaces, are best kept as separate utility programs since they may address the needs of a small group of users. Others, such as MAPGEN or FRFGEN, have a specific task that is distinct from the main program features.

 

·        How many utility programs are there and what are their functionality?

There are 14 utility programs and they each serve a specific purpose.

·    MAKE_PRJ

·    MAKE_CRD

·    MAKE_CMD

·    MAKE_FRC

·    MAKE_MOD

Create/edit data file

Programs in this group create (or edit) a MODENT data file. The file type is indicated by the utility name, eg MAKE_CRD creates a .CRD file.

·    EIG_UTIL

·    MAPGEN

·    FRFGEN

·    FRF2TIM

Manipulate data

Programs in this group manipulate existing data to create more complex input data files.

·    RD_ANSYS

·    RD_PATRAN

·    FILTER_U

·    RD_FRF_U

·    RD_TIM_U

Import data

Programs in this group import data, either from FE codes or covert  data universal file format to MODENT format.

 

·        Which is the most popular utility program?

It has to be FRFGEN because of its versatility. FRFGEN can be used to generate FRF or multi-excitation response files from .EIG data. It is quite handy for computing these from FE solutions or modal analysis.

Similarly, EIG_UTIL is also very popular because it allows the manipulation of .EIG files