Spectral Fatigue Analysis

Hello sir/madam,

I am Nalinii here and I am a final year student from UTP.I need to run spectral fatigue analysis for jacket platform.I would like to know the step to conduct spectral fatigue analysis in SACS.I would be really glad if sir or madam will be able to help me to show me  the procedure  especially after the eigenvalue analysis because I am having problem starting from that part.

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  • Nalinii,

    The typical steps to perform a spectral fatigue analysis in SACS are as follows:

    1. Create pilehead superelement (optional)
    2. Extract mode shapes
    3. Transfer function generation
    4. Spectral fatigue

    It appears that you have already performed step 2 so you should have your mass matrix (dynmas) and mode shape (dynmod) files. You then need to generate a transfer function which is used to convert the wave spectra into stress ranges for the fatigue analysis. This wave response analysis utilizes the dynmod and dynmas files to generate a SACS common solution file (saccsf) which contains the responses which define the transfer function. You can then run a spectral fatigue analysis on this saccsf file to generate your fatigue damage.

    I would recommend looking at Sample08 located in your SACS installation directory which contains a working example of what I just described. You may also want to refer to Section 4.3 of the fatigue manual for a more in depth discussion of spectral fatigue as well as Sample Problems 1 and 2 in Section 6.0 of the manual for other examples of this type of analysis.

    Regards,

    Geoff

  • Hi Geoff,

    Sorry to use this post to ask, i feel it is related. When I chose the General Wave Response or Deterministic/Transfer Function, there were no SACS common solution file generated as output. I would like to know if this is a software bug or do I need to modify any parameter in the input files so that I can get the (saccsf) file.

    Thanks a lot for your help

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