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# OpenSees Examples Manual Examples for OpenSeesPy

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## OpenSees Example 9. Build & Analyze a Section Example

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\n", "\n", "You can find the original Examples:
\n", "https://opensees.berkeley.edu/wiki/index.php/Examples_Manual
\n", "Original Examples by By Silvia Mazzoni & Frank McKenna, 2006, in Tcl
\n", "Converted to OpenSeesPy by SilviaMazzoni, 2020
\n", "This Example:\n", "https://opensees.berkeley.edu/wiki/index.php/OpenSees_Example_9._Build_%26_Analyze_a_Section_Example \n", "

\n", "\n", " This workbook demonstrates a Moment-Curvature analysis for two types of sections
\n", " 1. A uniaxial Section (moment-curvature relationship).
\n", " For the case of the uniaxial section, moment-curvature and axial force-deformation curves are defined independently, and numerically. The uniaxialMaterial command is used to define the moment-curvature relationship.
\n", " 2. A fiber section (standard W section).
\n", "For the case of the fiber sections (steel and RC), uniaxial materials are defined numerically (stress-strain relationship) and are combined into a fiber section where moment-curvature and axial force-deformation characteristics and their interaction are calculated computationally.\n", "

\n", " Even though the sections are defined differently, the process of computing the moment-curvature response are the same, as demonstrated in this example.\n", "

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### 2D vs. 3D

\n", "While this distinction does not affect the section definition itself, it affects the degree-of-freedom associated with moment and curvature in the subsequent analysis. \n", "There are two differences between the two models:\n", "
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1. The space defined with the model command (# Define the model builder, ndm=#dimension, ndf=#dofs)
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3. 2D: model BasicBuilder -ndm 2 -ndf 3;
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5. 3D: model BasicBuilder -ndm 3 -ndf 6;
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7. In the 3D model, torsional stiffness needs to be aggregated to the section
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\n", "This example demonstrates the case of 2D\n", "\n", "

\n", "\n", " Objectives of Example\n", " - Build a uniaxialSection: Flexure and axial behavior are uncoupled in this type of section\n", " - Perform a moment-curvature analysis on Section\n", "\n", "\n", " \n", " \n", " \n", " \n", "

### uniaxial Section:

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### Fiber Section:

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