Hi all,
I would like to know how SACS gets the 6x6 stiffness matrix created from pile super element or how SCAS considers the constraints of the whole jacket and other piles on a pile head.
I want to know its principle.Is there any other information i can check?
If anyone could help in this would be grateful.
Thanks in advance.
qian wen
I think SACS has lots of information that the user does not have access to. The documentation provided is just not sufficient.
Dear Qian Wen / DAC THUONG NGO,
The limitations of present age computing does not allow any software (not just SACS) to solve more than one non-linearity in a single analysis.
A typical example is a dynamic analysis with PSI. (which involves non-linearity of load and non-linearity of material [soil] ).
With the present computational power of Personal Computers / Workstations, such complex problems cannot be solved in a reasonable amount of time.
Hence a need for problem simplification arises.
What SACS / other softwares do for such cases is called as Sub-Structuring / Guyan Reduction / Static Condensation.
I would not expect SACS documentation to explain in detail about such methodology/techniques since these are beyond the scope of the documentation.
I am providing a few educational links for your reference:
If interested in the matrix procedures, I would recommend the book "Dynamics of Fixed Marine Structures by A.J. Adams and N.D.P. Barltrop".
Fun Fact: This book has been published before I was born, yet it is still relevant.
Thanks and Regards,
SWARUP Selvaraj.
Your suggestion inspired me a lot. I wonder if it would be great to extract the mass / stiffness matrix of the structure from SACS to ABAQUS. Maybe I can ask how to extract the stiffness /mass matrix of jacket structure from SACS as the substructure in ABAQUS?
Hi Qian wen,
You can get stiffness matrix of the substructure, which includes element stiffnesses as well as load matrix from SACS sub-structuring module. Even you can read it. Please make sure that DOFs are in correct order with respect to ABAQUS input lines. A word of caution; carry out verification checks on the transferred matrix. I am not sure on mass matrix, I am not sure, though.
I did a non-linear pushover analysis carried out using sub-structuring the decks of an offshore complex. The details are in the below link for reference.
https://www.offshore-mag.com/production/article/14040675/substructure-modeling-analysis-methodology-prolongs-life-of-zakum-offshore-complex
And how do I set the SACS input line to extract the stiffness matrix and the load matrix, where are they?
Answer Verified By: wenchengqian