Full Integration

CFV accepts stress inputs from Nastran, Ansys, Abaqus and Optistruct.

Full Integration with Stress Results File Formats

CAEfatigue VIBRATION has been developed to work with the stress solver formats from major FEA vendors. Note:  regardless of the stress solver used, care should be taken to ensure there is an adequate distribution of solution frequencies in the transfer function.  Also, the solution frequencies need to be adequately spaced to pick up resonances (the FREQ4 card in Nastran is a good tool for this) as well as a finely spaced set of solution frequencies in any location where the input load changes. See the CAEfatigue VIBRATION User Guide for further information.

Nastran (MSC, NX or NEi)

It is assumed that a Nastran steady state dynamic analysis (either SOL111 modal or SOL108 direct) has been run with the following parameters.

  • An OP2 file has been specified using PARAM,POST,-1. This produces what is commonly referred to as an “old” OP2 file.
  • Stresses must be written using the default method (SORT1).
  • Stresses can be requested using the CORNER option (either BILIN, CUBIC or SGAGE) or the CENTER option. Incidentally, when making the CORNER request, centre results are also written and so the CFV software calculates results at both centre and corner locations in this case.
  • It is recommended that only one data block containing stresses using STRESS or ELSTRESS (Physical Output) is requested. This can be achieved by using only one FREQUENCY (Dynamic Solutions Conditions) card above the 1st subcase or by having the same FREQUENCY ID if repeated within the subcases.
  • Subcases in the Nastran file are numbered and the CFV Control File should correctly use this numbering.

    The CFV code supports both multiple subcases being used consecutively and multiple subcases being used simultaneously (with correlation).


CAEfatigue VIBRATION supports the RST stress result file format assuming the following:

  • Ansys support is provided for RST files with only single subcases included in each RST.
  • Multiple RST’s can be specified in order to apply multiple events (consecutively) but only single random loads are supported for this release (multiple correlated random inputs are not supported).
  • Subcases in the Ansys RST file are not numbered. Inside the CFV code it is assumed that subcases are numbered consecutively according to their order in which they are specified in the Control File.
  • Ansys only outputs results at corners (OUTRES,STRS,ALL). In order to provide data at centers the results are calculated as the linear average of the corner results. These element center results are not as accurate as the corner results and should not, in general be used in preference to the corner results.
  • If a static load is applied this must be provided in a separate RST file and the elements in the dynamic and static RST files must be identical.
  • Make sure that the RST file containing the required static subcase contains only one subcase.
  • Ansys versions 14.5 and later are supported.


CAEfatigue VIBRATION supports the ODB stress results file format assuming the following:

  • Abaqus support is provided for ODB files with single or multiple subcases included in the ODB file.
  • Abaqus outputs results to either corners or centers (*Element Output, position = NODES or *Element Output, position = CENTROIDAL) but not to both. Note that in the CSV Control File the appropriate entry for GIDOUT (Center or Corner) should be specified on the vIBFAT card.
  • If a static load is applied this must be provided in a separate ODB file and only elements in both the dynamic and static ODB files will be used for output.
  • Make sure that the ODB file containing the required harmonic subcases contains only those subcases.
  • An ODBMAP card must be used in CFV to assign number to the STEP names. This is REQUIRED.
  • Abaqus 6.14, 2016, 2017 and 2018 are supported.
  • If corner results are requested the CFV code will add additional results at the centers based on a linear interpolation of the corners. This is done for purposes like hot spot detection but generally the use of these center results should be avoided (the corner results are more accurate).


CAEfatigue VIBRATION supports the OP2 stress results file format in the same way as Nastran with a couple of small exceptions:

  • Optistruct support is provided for OP2 files in the same way as Nastran.
  • Optistruct behaves in a very similar way to Nastran with a couple of small exceptions.
  • Firstly, when writing stresses for separate subcases, Optistruct will always write separate data blocks. This needs to be flagged in the CFV Control File by specifying “source” entry as “OS” in the vIBFAT card.
  • Secondly, when comparing analysis runs with other Nastran codes be careful to check which PARAM instructions are applicable. Not all PARAM codes are used in Optistruct.
  • RELRESP is only supported with the latest 2018 version of Optistruct.
  • If corner results are requested the CFV code will add additional results at the centers based on a linear interpolation of the corners. This is done for purposes like hot spot detection but generally the use of these center results should be avoided (the corner results are more accurate).

Spot Weld and Seam Weld Analysis

Spot Weld and Seam Weld in the Frequency Domain

New Feature! Conduct Frequency Domain Based Spot Weld and Seam Weld Analysis

CAEfatigue Limited  has develop an industry first!  With the addition of our new module, CF_JOINTS, CFV will now allow the User to conduct spot weld and seam weld analysis in the frequency domain.  This is a tremendous breakthrough and will provide the automotive industry, and others, the capability to analyze complete vehicles including any included spot welds or seam welds in a single analysis.

Various Screen Shots from the Windows GUI Application for Spot and Seam Weld Analysis

Use Fringe Plotter to see Random Response and Damage results.

Use Event Plotter to visualize the most damaging Events applied to the model.

Hide various element sets to help visualize components of interesting detail.


Improved GUI

Our Windows GUI has improved plotting features.

Improved GUI to Visualize Random Response and Fatigue Results

CAEfatigue Limited has significantly improved our GUI application for Windows users by providing enhanced plotting features to view numerous PSD responses results for any element, grid, layer or events ID in your analysis.  This GUI application now gives the user the ability to view and edit control files either directly in the file or through an improved interactive control file Wizard that helps the novice user understand the inputs required for the job.  When a control file is running, the user can observe the progress via the Console view.  Once the job is complete, the user can see a summary of worst case results immediately in the Log view.   The User can then view the results with our new PSD Matrix viewer, improved PSD Plot viewer, improved Event Plot viewer and vastly improved Fringe Plot viewer.  When using our TIME2PSD module (or CAEfatigue CONDITIONING), the user can see the FFT results via the FFT Plot viewer.  Results will include the original time history, the time history with or without deletes and the final PSD shapes.  The GUI is a great alternative interface for when job control via the console is not desired.

Various Screen Shots from the Windows GUI Application

Edit the control file with our Wizard features.

View a log file after the job completes for a quick insight on results.

Only have a time history?
Use our time history to PSD conversion.

After an analysis, plot input PSD, transfer function and output PSD.

Review sine sweep results.

Plot direct and cross PSDs after converting multi input time histories.

Fringe Plot results directly on the model including RMS Stress, RMS Strain, mean stress, damage, life, etc.

Turn element sets on and off
to better view model results.

Coupled with CAEfatigue RANDOM, review minimum clearance between components to evaluate impact.



Convert your time history to a PSD and insert it into your analysis as part of a single job run.

Fully Automatic Time History Conversion

CAEfatigue Limited has significantly improved its time history to PSD conversion process by including automated smoothing tools to calculate the appropriate window length and overlap as well as automatically deleting sections of the time history that does not contribute to the damage.  These automated tools are included in our software product CAEfatigue CONDITIONING (CFC).   Whether you are using the manual TIME2PSD conversion method included with CFV or our new automatic conversion software CFC, the user simply needs to select the time history to convert and we will handle all the hard work including the tracking of all output PSDs and cross PSD that can be very complex when dealing with multi input time history conversions.


Collision (Impact) Detection

Determine if parts might impact each other under dynamic response motion.

Collision (Impact) Detection: Determine if two parts are likely to hit under dynamic motion

CAEfatigue Limited now offers a first in the industry … Collision (Impact) Detection!   CAEfatigue RANDOM coupled with CFV, can analyze the dynamic motion of separate parts of your model and assess the probability that the parts will touch due to excessive dynamic response motion (i.e. excessive displacement).  This new feature takes into account phasing of the motion between the two parts as part of this impressive feature.

This enhanced capability comes as a direct result of a Customer request.   CAEfatigue Limited is committed to listening to our Customers and giving them the options and capabilities they need.  Our next advancement will be to reverse our collision detection tool and turn it into a gap detection tool.  This can be important if you do not want two parts to separate during excessive motion.  Look for this enhancement coming soon.

Collision Detection.   A Completely New Feature in CFV when coupled with CFR

Will the exhaust system hit the vehicle body under dynamic motion?

Use Collision Detection and see the probability of impact between the exhaust and floor pan.

Will the doors hit the vehicle body under dynamic motion?

Use Collision Detection and see the probability of impact between the door and door frame.