The OpenSees applications allows developers to use their own material modules to the application. Unlike most other programs, the materials are added at run time and not at compile time. The advantage of this is the developers:
1- Do not need the OpenSees source files or libraries to compile and link the application.
2- Can share their modules with others without having to provide the source code.
For those new to programming NEVER EVER NEVER start with an empty file. Take something similar that works and make changes to that file. So, for the purpose of adding your code to OpenSees, C++, C and Fortran examples are provided here:
http://opensees.berkeley.edu/OpenSees/developer/ 👇👇👇

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A powerful 7.3 magnitude earthquake near the Iran-Iraq border killed over 400 people and injured thousands, sent residents fleeing their homes into the night and was felt as far away as the Mediterranean coast. The quake was centered 19 miles (31 kilometers) outside the eastern Iraqi city of Halabja, according to the most recent measurements from the U.S. Geological Survey. It struck at 9:48 p.m. Iran time, just as people began retiring for the night. The quake's worst damage appeared to be in the town of Sarpol-e-Zahab in Kermanshah province, which sits in the Zagros Mountains that divide Iran and Iraq.
May peace be on them and condolences to their dear families, for this loss.👇👇👇

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Prof. Jack Baker (Stanford University) discusses methods of ground motion simulation and approaches for simulation validation.👇👇👇

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It is established beyond doubt that a structure’s behavior forms by selecting appreciable elements in modeling process. It takes a little practice to know when to use the different commands for different behaviors. I denominate this skill " Main Idea of Simulation ".
From my own perspective, the SFI_MVLEM command has a more profound impact on the accuracy growth of a RC Wall simulation. The SFI_MVLEM command is used to construct a Shear-Flexure Interaction Multiple-Vertical-Line-Element Model (SFI-MVLEM, Kolozvari et al., 2015a, b, c), which captures interaction between axial/flexural and shear behavior of RC structural walls and columns under cyclic loading. So, what you need is to know an important point, in case of using this command. In near future, i will aptly elucidate my viewpoint through one outstanding reason/idea.👇👇👇

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Let me close today’s discussion with suggesting two appreciable points which i denominate them " Blue-Green Ideas ":
1-Do not panic for changing place of the RC Wall, in case of using SFI_MVLEM command. From my own perspective, either RC Wall is located in bay-1 or bay-2 or bay-3, you should consider it in bay-1. In other words, using this way you divide the structure’s behavior into two parts; " RC Wall’s behavior " and " RC Frame’s behavior ".
2- As may seem in the figure, bay-2 is unreal (Rigid diaphragms) and considered for connecting two mentioned parts of structure, in simulation process.👇👇👇

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As the longest night of the year ends, we are hopeful that beautiful, bright and successful days are going to come our way.
With that thought, I wish you a very warm and "Happy Yalda Night."

Install Opensees 2.5.0 + Active Tcl 8.5 + Tcl Editor (Windows 64-bit):


First uninstall all versions of ActiveTcl and Opensees which is existed in your Computer. Also erase Tcl and tcleditor folders in local Disk (C).
Then unzip attached file and accomplish steps1 to 3:
1. Copy tcleditor folder into Disk (C).
2. Install "ActiveTcl8.5.18.0.298892-win32-x86_64-threaded.exe".
3. Copy and replace OpenSees 2.5.0 (rev 6536) into "Disk C/tcleditor/bin".
4. Now, use it and enjoy!!

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Prof. Julio Garcia discusses Earhquake simulation of Soil-Structure Interaction. The motion is produced by a harmonic shaker. A total of six frequencies of excitation are reached and displayed.
Frequency No 1: the system moves with such a frequency, that the whole system reacts almost as a rigid body.
Frequency No. 2: the excitation frequency increases and the frequency of the site is reached. The horizontal springs react. There is almost no reaction from the pendulums.
Frequency No.3: the excitation approaches the vibration frequency of the soil-structure model.
Frequency No. 4: the system reaches the fundamental frequency of the fixed base model. The soil-structure model does not react.
Frequency No. 5: the vibration frequency increases up to the second frequency of the fixed base model. The soil-structure model does not react.
Frequency No. 6: the vibration frequency decreases until the rest condition is reached.
Watch it and enjoy!!👇👇👇

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In this video, Prof. Terje Rølvåg discusses how you calculate and apply mass and stiffness proportional (Rayleigh) damping to FE models. He also explains why you should be careful with mass proportional damping!!👇👇👇

🆔 https://t.me/OpenSeesCommunity

Let me close today’s discussion with a novel suggestion to keep in mind while you are using a convergence algorithm for time history analysis.
From my own perspective, best priorities for analysis parameters are as mentioned below, to achieve appreciable convergence:
1- Changing Solution Algorithm
a) Trying Newton with Initial Tangent
b) Trying Broyden
c) Trying NewtonWithLineSearch
2- Trying reducing the time step by 2: dtanalysisnew=[expr
$DtAnalysis/2]
3- Trying reducing the time step by 10: dtanalysisnew=[expr
$DtAnalysis/10]
4- Trying reducing the time step by 100: dtanalysisnew=[expr
$DtAnalysis/100]
5- Try the previous methods with the smaller timestep:
a) Trying Newton with Initial Tangent
b) Trying Broyden
c) Trying NewtonWithLineSearch👇👇👇

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As i mentioned, a little while ago, sometimes we are going to accomplish three-dimensional simulation of a bridge that has a continuous concrete deck with the bents being integral, and the dual-column bent caps for the bridge are supported by reinforced concrete columns.
Following figure indicates the sample of first vertical bending mode shape of mentioned bridge with period of 0.33 sec.👇👇👇

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This figure indicates the sample of first rotational mode shape of mentioned bridge with period of 0.31 sec.👇👇👇

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