OpenSees Example 9. Build & Analyze a Section Example: Difference between revisions
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Revision as of 22:02, 11 November 2009
Introduction
For the case of the uniaxial section, moment-curvature and axial force-deformation curves are defined independently, and numerically.
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.
Input
Model Building
- 2D vs. 3D
- 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.
- There are two differences between the two models:
- 1. The space defined with the model command (# Define the model builder, ndm=#dimension, ndf=#dofs)
- 2D
- model BasicBuilder -ndm 2 -ndf 3;
- 3D
- model BasicBuilder -ndm 3 -ndf 6;
- 2. In the 3D model, torsional stiffness needs to be aggregated to the section
- 1. The space defined with the model command (# Define the model builder, ndm=#dimension, ndf=#dofs)
Uniaxial Section
Files
Notes
- Flexure and axial behavior are uncoupled in this type of section
Lateral-Load Analysis
The following tasks are performed in the analysis
- define lateral-load parameters
- analyze
Static
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Dynamic EQ Ground Motion
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Run
The model and analysis combinations for this example are numerous. The following are an small subset, for demonstration purposes:
- To run W-Section Model, Static Pushover Analysis:
puts " -------------Elastic Model -------------" puts " -------------Static Pushover Analysis -------------" source Ex8.genericFrame3D.build.Wsec.tcl source Ex8.genericFrame3D.analyze.Static.Push.tcl
- To run RC Model, Uniform Earthquake Excitation
puts " -------------Uniaxial Inelastic Section, Nonlinear Model -------------" puts " -------------Uniform Earthquake Excitation -------------" source Ex8.genericFrame3D.build.RCsec.tcl source Ex8.genericFrame3D.analyze.Dynamic.EQ.Uniform.tcl
Notes
In this example, the following items are variables:
- Number of stories in Y direction
- Number of bays in X direction
- Number of bays in Z direction
- Elastic/Fiber Section
- Display: none/node numbering/deformed shape/mode shape (can choose which mode) (variable display scaling factor for both the deformed shape and the mode shape, this scaling factor is dependent on the user choice)
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