Current Revision posted to Structural Analysis and Design Wiki by jeremyhoesly on 7/25/2013 9:26:32 PM
(11.27.2012) Bentley- Analysis and Design of Fixed and Floating Offshore Structures eSeminar Attendee Questions
design,Offshore,structural,P-Delta,SACS
This eSeminar was originally presented on Nov. 27th, 2012.
You can view the recording online at our BeConnected site (Click Here!).
The following are the product-related questions and corresponding answers from the eSeminar.
- Q: Why is the bottom bracing pattern is different than others?
A: You may have a mudmat at the bottom of the jacket in which would be around the four corners. An X brace would not work for that. - Q: Does the program calculate the self-weight of the structure?
A: Yes, it will calculate the self-weight of the structure. You can view the self-weigh in precede. - Q: Is that a new precede version?
A: Yes, it will be SACS version 5.5 which will be available very soon.that. - Q: How can we do actually a Push-over Analysis in SACS?
A: The SACS Collapse module is capable of doing this. - Q: Is Push-over analysis is compulsory required for this very rigid/stiff offshore jacket structure?
A: It depends. If it is an existing structure then the assessment initiators may force a pushover analysis. In any case, the structure may be stiff but the foundation may be weak. - Q: How we can decide the size of the jacket leg?
A: You can look at a similar design in the area. - Q: We can see different types of bracing connections, is there any particular method to select type of bracing connections?
A: Different bracing is possible; it depends upon the amount of redundancy required for the structure. - Q: Which method of analysis is needed for FPSO, Barge structures?
A: SACS does not design the actual hull of the vessel, only TOPSIDE design for FPSO’s and Transportation analysis using barges. - Q: Does the analysis consider P-Delta effects (global and local)?
A: P-Delta effects can be included in both static and dynamic analysis. - Q: Can SACS check fatigue strength for w-shapes and their connections?
A: Yes, provided users supply their own SCF’s. - Q: Can you view the wave loads applied to the structures?
A: Yes, it is possible to do this. The SEASTATE module will generate an OCI file which will contain both the structure and the generated wave loads on the structure. This file can be opened in Precede to view the loading. - Q: With SACS version 5.5, what export options are available?
A: Precede will export to PDMS and SDNF formats. But the link to ISM allows the user to link to other Bentley products in addition to products such as TEKLA, Revit, and AutoCAD. - Q: Does SACS perform mooring analysis?
A: Currently Mooring analysis is not possible. - Q: Are the elements used to model the deck plate meshed at runtime? The concern here is the transfer of area loads applied to the plate element to the supporting members.
A: Deck plate elements are not automatically meshed at run time. Users have to refine the model before a run. - Q: How much is SACS basic module?
A: Please contact our support center for this information.http://selectservices.bentley.com/en-US/ - Q: Is there a trial version available and online training?
A: SACS does not have a trial version. There are online resources available for self-training: http://connected.bentley.com/BrowseLive.aspx?BrowseType=0/ and http://learn.bentley.com/app/Public/ViewLearningPathWithMasterCourseExpanded?lpId=100334&mcId=100429/ - Q: Does SACS perform passing vessel analysis?
A: Currently multi-body analysis is not possible. - Q: Will Rhino upload be available for other stuctures besides hull forms?
A: Currently, Rhino compatibility is only possible with the Hull module. - Q: Can you input load histogram for fatigue?
A: If you mean scatter diagrams, then yes, this is possible with the Fatigue module. - Q: Are there any validation of dynamic analysis is available on Bentley’s website?
A: There are no validation examples. However, the software comes with Demo’s and Sample cases. - Q: How does SACS handle torsion? I read in the manuals that SACS calculates torsion and adds it to the shear stress. In the post processing output files, when we see "Shear Stress,” does that include the torsion values? I know in STAAD, using Canadian code, torsion is not checked. How can I verify torsion is checked?
A: The bending stress from Torsion in included in the weak axis bending component for the flange sections. - Q: Does SACS perform pile driving analysis?
A: SACS does not have Pile drivability analysis. - Q: Is there a training center where I can learn more about fixed and floating offshore platforms for those interested to venture in this field of profession?
A: You may want to enquire which colleges offer such courses. - Q: Do you just model the members using frame model? Can truss model be used for some members?
A: Member end releases can be used to model truss frames. - Q: Does SACS integrates with AutoPIPE's model?
A: Currently there is no link to AutoPIPE. However this is something Bentley is very interested in doing. - Q: Is the P-Delta calcs based on revising the stiffeness matrix or trial-and-error?
A: The stiffness matrix is modified for the P-Delta analysis. - Q: How does the program address joint design (punching, stub ends, etc.)?
A: The SACS Joint Can module has many different code check criteria for Joint Design. e.g. API, ISO, NORSOK, etc.. - Q: Does it check the combination of column stresses and brace imposed stresses at the joints?
A: The joint design module (JOINT CAN) takes this into account. - Q: By the use of the Translator or converter "STAAD.Pro to SACS", is possible to translate STAAD geometry, beam and plate properties to its equivalent SACS representation. Is it possible the inverse (SACS to STAAD.Pro)?
A: A two way transfer of information between SACS and STAAD is possible via ISM. - Q: Can SACS simulate an Impact analysis?
A: Yes, both statically and dynamically and also account for nonlinear geometric and material behavior. - Q: What happened to the 3D PDF feature available in some older versions?
A: It is still available but through ISM. - Q: Is SACS compatable with STAAD.Pro?
A: Yes, via ISM. - Q: How accurate is the conversion between STAAD to SACS? Is there much in the way of extra handling required?
A: Loads are not transferred. Also, STAAD has a large library of sections used in the civil market and not in the offshore industry. These cannot be translated. - Q: Can users modify input file using text editor?
A: SACS has its own intelligent text editor “Datagen” which can recognize the content of the input file. Otherwise any text editor will work provided it doesn’t leave control characters in the input. - Q: Can SACS generate plate meshes automatically?
A: Yes, this is possible. Obviously for a complex geometry a FE mesh generator such as FEMGV can be used. SACS can import meshed surfaces from FEMGV. - Q: Can we create row lines (A,B,C or 1,2,3) manually?
A: Currently, this is only possible via the Structure Definition Wizard. - Q: Is fatigue analysis done in frequency domain?
A: Both frequency and time domain analysis are possible. - Q: How about validation for EQKLOD line?
A: We do not have any validation examples available at this moment. However we will gladly look into the problem if you there is a discrepancy with the method. - Q: Can SACS do model generation for jackets only?
A: Currently, the structure wizard only handles jacket types of structure. However, there are features under the joint meshing which can probably handle other configurations such as decks, spherical, and cylindrical structures. - Q: How do you decide the appropriate number of modes for the dynamic analysis?
A: The results from a modal analysis will include a report on mass cumulative factors. Enough number of modes should be used so the cumulative mass is over 95% in case it’s needed by any response analysis. Depending on the model, this is not always possible, but it’s a good indicator of how many number of modes should be used. - Q: Can your sea state be defined by Jonswap or Ochi-Hubble Spectrum?
A: Yes, including a user defined spectrum. - Q: After analysis and design, how easy is it to transfer to detail drawings for fabrication and construction?
A: The ISM interface provides links to numerous CAD packages. - Q: Can you explain the integration of the GH Bladed software for offshore wind turbine structures?
A: The GH Bladed software outputs a special file for SACS which can be used to automate the fatigue and strength analysis. The analysis process is speeded up using the multi-core functionality of the PC. - Q: Will SACS offer in the future unbraced lengths for top flange or bottom flange for W Members?
A: The unbraced length can be entered on the GRUP line. - Q: How does the program address vessel bending for FPSOs?
A: The new SACS Stability module allows for a longitudinal hull strength analysis which takes into account both the hogging and sagging of the hull structure. - Q: Has EDI systems (originator of SACS) been acquired by Bentley?
A: The SACS software was acquired by Bentley Systems in March 2012. - Q: Are there specific checks within SACS to avoid the onset of VIV of a tubular member (wind induced)?
A: Currently, there is no check for vortex induced vibration. - Q: Does SACS adopt section wizard?
A: The section wizard functionality is not currently available in SACS. However, Bentley intends to add this in the future. - Q: How accurate are plate & shell fatigue checks? Can we get hot spot stress at points of interest?
A: The plate and fatigue checks are dependent upon the mesh density in the crucial areas of stress concentrations. Obviously a finer mesh in these areas will yield a better representation of the hot spot stress. - Q: Can SACS perform non-linear time history analysis?
A: The equivalent static incremental loads from a time history analysis can be passed through the SACS Collapse module to check for an Elasto-plastic response. - Q: How do we learn more about this year’s Be Inspired Award winner and finalists in the Offshore Engineering category?
A: Bentley is proud to have received a number of great use cases for this new category. The Offshore finalists and winner were outstanding uses of Bentley products for their offshore projects. Consider entering your innovative project in next year’s competition, which will be announced in Spring 2013! - Q: How do we get the continuing education credits? How can I get a certificate of attendance of CEU's?
A: Bentley Learning Units (BLU), Bentley Institute’s equivalent to Professional Development Hours (PDH), are granted for the live and recorded eSeminar. Within 2-4 weeks of watching the presentation, Learning Units are added to your transcript. To access your transcript, go to www.bentley.com/mylearninghistory. On the "My Learning History" page, there is a detailed how-to guide related to Learning Units and transcripts, in addition to the link to the user’s online transcript. In most states, users can submit their Bentley transcripts for consideration for continuing education credit toward their registration renewals. - Q: How do I view this eSeminar again or share it with a colleague?
A: This event along with the live Q&A were recorded and it is available online at our BeConnected site.