question marks

Input

  • What options do I have for checking the input data?
  • FEMFAT provides the user with a variety of options for checking input during analysis preparation or following the analysis. These are:

    FEM-Model

    •Number of imported nodes & elements (Caution: some "exotic" element types are ignored).

    •Dimensions of model (unit correction to mm may be necessary)

    •Minimum/maximum shell thicknesses

    •Visual control in VISUALIZER including group definition; groups can be displayed in the main program as a label list.

     

    Material Data

    •Numerical control of the data in the material menu

    •Graphical control using the Haigh diagram, S/N curve and cyclic σ - ε diagram

    •In the node characteristics menu by browsing in the node labels for checking all properties (material, roughness, temperature, surface treatment,...)

     

    Stresses

    •In BASIC maximum principle stress of the element with the highest v. Mises equivalent stress

    •For MAX, visual control of the stress sequence or the unit stresses is available in the VISUALIZER.

     

    Menu Item "Check Input Data"

    This function is available immediately prior to starting the analysis that allows a number of input data to be double-checked, in particular, whether the stresses and the material strength form a plausible relationship in terms of the required analysis result (endurance safety factor, damage life in the finite life domain, static safety). Implementation of these checks is strongly recommended, see figure below.

    Note:

    Execution of this function may take some time in MAX, especially if the scratch files have not yet been created.

     

    The following data can be examined in detail:

    •Analysis aim: Endurance, damage, static safety .

    •Analysis group: Name and number of nodes and elements

    •Materials used in the analysis group, including data plausibility check

    •Activated influence parameters

    •Stresses

     

    1. Maximum occurring v. Mises stress for the entire load history compared to the local tensile strength/yield stress.

    2. Maximum v. Mises stresses of individual load channels (ChannelMAX only).
    This function is very useful for estimating the influence of certain channels on the overall result. For example, using the modal superposition method a frequency boundary can be defined in this way above which the higher frequency modes need not be taken into consideration due to the small stress value.

    Because the load-time histories and the channel stresses are combined for this function, inconsistent units can also be easily discovered.

     

    Results

    •Result dialog: Maximum stressed node, S/N curve, utilization statistics.

    •Distribution of all scalar result variables on the model: Any postprocessor can be employed for this or, most comfortably, the VISUALIZER.

     

    Documentation

    •FEMFAT Job File (*.ffj): Necessary for subsequent batch operations.

    •FEMFAT result protocol (*.pro): Detailed information in text format

     
    It is highly recommended to archive both outputs for subsequent comprehension of the analyses; the exact settings can be forgotten faster than you think.

  • What is “on demand” variable licensing and how do you configure it?
  • Up until the release of version 5.1, the FEMFAT license module retrieved all the necessary and available licenses from the license server unless other settings had been specified manually.

    Since the release of FEMFAT 5.1, individual licenses are only retrieved while the server is being used and they are made available again during times of non-use.

    In this regard, it is also possible to specify a timeout which defines the time interval of the users inactivity after which the license is once again made available. This has the advantage that other users can use the licenses and therefore, no valuable resources remain unused.

    The default value for the timeout is 15 minutes. The “MAGNAECS_LICENSE_TIMEOUT” environment variable allows a value of between 5 and 9999 minutes to be set.

    If work with FEMFAT is resumed after the timeout value was exceeded, FEMFAT attempts to retrieve the required licenses once again. If they have already been reassigned, then there are the options of either waiting until a license becomes available or of saving the state of the model temporarily and continuing work at a later point in time. However, FEMFAT will be exited either way. For analyses which are carried out in batch mode, the keyword “-queue” can be used to prevent FEMFAT from aborting the job due to a lack of licenses and writing an entry into the message file. Instead, FEMFAT then waits with the further processing until a sufficient number of licenses are available.

    This means that, overall, variable licensing provides significant improvements: Licenses are only blocked as long as they are actually required for an analysis. This increases the utilization capacity of the existing licenses when there are several analysis engineers working with one license pool.