• SACS TOW Analysis

    My Towlst file Weight from "SACS MODEL Added Weight Data" doesnt match with Gravity load case (Stage 1 of Transportation). I want to know how the value can modify by using the same file ?? ( I had copied load case of 800A from seaoci.static & entered…
  • Force Couples in Tow Analysis

    I am performing a transportation analysis using static gap and tow gap analysis. A force couple load combination is used to move the center of gravity of the structure being transported to a specific location. The static run produces the following final…
  • Center of Motion - SACS Tow

    Dear All, I am doing tow analysis in SACS by going through 'Learn Server' videos. I am not sure 'What center of motion in TWOPT command line dictates?. Is it the difference in COG between structure and barge?. I am aware that CENTER OF MOTION in SACS…
  • About designing of a structure

    Hello everyone My name is Sara from Italy, I am very new to the Sacs, could you please help me First of all; after assigning all the member sections in order to perform static analysis, shall I calculate all the section's self-weight by myself and…
  • Real and Imaginary Load Cases in SACS (Fatigue analysis)

    Hi There. I'll be grateful If anybody explain me following problem: I came across the problem while I was studying this topic https://communities.bentley.com/products/offshore/w/wiki/39310/tow-fatigue-with-sacs I understand that we use RAO to derive…
  • moses bending moment on barge

    Hello, I'm trying to compute the bending moment on the barge after a transportation analysis executed in MOSES (via the inst_transp macro). I started considering the FRQMEANA load case (in my understanding is the static with no environmental forces…
  • Tow Fatigue with SACS

    Hi there. I need to perform Fatigue analysis for sea transportation in order to understand this calculation I started studying this guide "Tow Fatigue with SACS". I ran into a problem, if I understood correctly this formulas => have to calculate these…
  • Regarding selfweight doubled in Sacs Tow file while using RBMASS calculation to find Mass moment of inertia of a system

    Hi I tried to find Mass moment of inertia of my structure using TOW-RBMASS command. ALL LOADS i specified in my main *.INP file and when try to check in the Tow output i find that self weight is added or duplicated again in the RBMASS case alone. switching…
  • Help with SACS Transportation Inertia Load analysis

    Dear Colleagues, Hi I am new with SACS, and am working on inertia loading generation with SACS tow module. I have some confusion with the notation system that SACS tow adopt. Let's say we have conventional seakeeping coordinate system (X-surge, Y…
  • RE: inertial forces for bodies underwater

    Samsul, The only way to generate added mass and entrapped mass in SACS is through the Dynpac analysis. You can specify the added mass coefficient and flooding options on the DYNOPT line of the Dynpac input file. The added mass and entrapped mass will…
  • RE: Dynamic Analysis in SACS

    Camille, You can use RAO's in conjunction with a wave height and period to generate a resulting inertial load on the structure which can then be solved to check the member stresses. However, SACS does not perform a dynamic analysis for this response…
  • RE: Can we use load RAOs to generate common solution file with inertia loads for fatigue analysis. If yes, how it can be done?

    Anupam, Let's first look at the input requirements for a tow fatigue analysis: Fatigue Input File (ftginp) Common Solution File (saccsf) Seastate Input File or Tow Input File (towinp) The fatigue input file defines the fatigue cases which…
  • RE: Transportation analysis including weights

    Michael, The above tow input file should be fine as long as you have defined your model input file correctly. It is difficult to say what may be wrong without looking at the model file and run file associated with this analysis, but there are a few…
  • RE: How to perform spectral fatigue analysis using SACS

    Stephen, You need to do a Tow Fatigue analysis. Tow Fatigue will analyze fatigue damage of a structure by generating transfer functions using motion RAO's (Velocity, Motion or Acceleration RAO's) and combining those transfer functions with the wave…
  • RE: Towing analysis of a slender Pile in a Jack up barge

    I don't think I understand what you are trying to analyze. It sounds like you are asking if you can perform an analysis of the pile using inertial loading from transportation. This can be accomplished using the tow analysis where you can model the pile…
  • RE: tow analysis from motion response

    Hello, All you need to do is add the 'MOTION' line into your TOW input line. This will allow you to add your roll, pitch and heave data. You will also find the information you need to carry out your TOW analysis if you take a look at Sample 2…
  • RE: Transportation analysis by using SACS with G-forces.

    Derek, Please tell us what do you mean by this line But someone told me you have to input G-force and angular acceleration in Max acceleration together? However we do have options to input both G-force and acceleration in towinp file.
  • RE: SACS - Frequency Domain Transportation

    Kasiphon, Currently we only support frequency domain analysis in tow fatigue. I have been talking with our developers about implementing the maximum probable stress calculations based upon the stress RAO's as a possible enhancement for a future release…
  • RE: A couple of questions

    In the case of tow fatigue, the naval architect would typically provide the structural engineer with response amplitude operators (RAO's) which are calculated using their hydrodynamic analysis in MOSES. The structural engineer would then calculate the…
  • RE: A couple of questions

    1. The center of roll depends on the properties of the vessel as well as the cargo. You will need to perform a hydrodynamic analysis in order to find the center of roll. Typically you will get this information from your Naval Architect. MOSES can be used…
  • RE: Structural analysis of a free floating jacket

    Cris, If you already have the motion data, you can perform a tow analysis to convert the motion data into inertial loading on the topsides structure. You can enter your motions as motion data, RAO's or accelerations. You may refer to the Tow manual…
  • RE: SACS Motion Analysis for Tow

    Siddhant, There are two options that you have to generate static load cases for Tow analyses: You should be able select No when exporting to SACS TOW file to export acceleration load cases (See Below). You will have to manually define the load cases…
  • RE: SACS Motion Analysis for Tow

    There are two ways that you can run Motions analysis in SACS. You can either use the SACS Motions program or the SACS Motions/Stability module. Since you have created the hull in maxsurf, I would recommend using the SACS Motions program to run the motions…
  • SACS Motion Analysis for Tow

    Hello! I am analyzing a Jack Up Rig with a single column for wet tow. During wet tow, the jack-up will be floating on its hull and the column will be above water. The procedure I have adopted is as follows: 1. Perform a wave dynamic analysis in SACS…
  • SACS RAO - strange output and input

    I am curious about RAO command in SACS Tow input file. See attached picture, I put RAO = 1g (m/s^2 /m) which is already base on unit wave amplitude (Wave height / 2). Unit wave amplitude is 1m. (Wave Height = 2*1m = 2m) Then, SACS should give…