#W1 |
Wed April 28, 2021
Introduction to OpenSees
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Introduction to OpenSees ...
- Introduction to the “Get Started in OpenSees with STKO” Course
- What is OpenSees: history, development, logic, components, use and applications for simulating the response of structural and geotechnical systems subjected to earthquakes.
- Tcl basics to use OpenSees with STKO.
- References and resources for further study.
Prerequisites:
- Concepts of Finite Element Modeling
Materials and Resources:
- Powerpoint
- References and links to OpenSees resources and Tcl scripting basics provided in the powerpoint presentation. utils0.tcl - utility file for unit system setup and conversions Click here to access the course forum Click the title to view the youtube recording of the course.
Exercise:
- ex0.tcl - tcl basics to tryout in the Python interpreter
- ex1.tcl - Fixed beam with distributed load example
- ex2.tcl - Fixed portal frame with distributed load example
Homework: Choose your own analytical problem to recreate in tcl, set up your unit system and run it in STKO by plotting the relevant results.
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#W2 |
Wed May 5, 2021
Introduction to STKO
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Introduction to STKO...
- What does STKO add to OpenSees?
- Motivations for developing STKO
- How are OpenSees logic abstractions implemented in STKO?
- HDF5 Database
- MPCO recorder
- CustomCommands
- Differences between STKO and other FEM Software
- Installation Guide
- Python Basics
- 2D frame structure example (just showing a complete model plus something in the python scripting inferface, calculations, and check)
- Applications examples
- How to install it
Prerequisites:
- Concepts of FEM
- Week 1 Introduction to OpenSees
Support Material:
- References and links to all STKO resources and Python scripting basics provided in the powerpoint presentation
- ex2bis.tcl Same as ex2.tcl but in 3D and with an mpco recorder class inside
- ex2tris.tcl Programming loop for geometry generation, ex3.scd 2D Portal frame in STKO (same as ex2.tcl)
- utils_1.py Python file for basic calculations and for assigning a property from the Python API.
All files are in the downloadable zip file.
Homework: Tryout making the same tcl example from week 1 back in STKO, just exploring the software, and try to complete ex2tris.tcl with a full scriptRead more
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#W3 |
Wed June 9, 2021
Model Definition in STKO
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Model Definition in STKO...
- Detailed presentation of the pre and post processor interface
- Description of the workflow commands input (work tree, toolbar, navigation menu, terminal)
- Quick toolbar
- Keyboard and mouse commands
- X-objects and indexing
- Navigation, visualization, quick toolbar tools
- Color coding of properties
- Shortcut keys + generic tips
- STKO-OpenSees parallelism
- Model overview of a 3D elastic frame structure and addition of nonlinearities
Prerequisites:
- Concepts of FEM
- Week 1 - Introduction to OpenSees
- Week 2 - Introduction to STKO
- Installation of STKO on your computer
Materials and Resources:
- Powerpoint presentation
- ex4.scd: complete 3D elastic frame structure, gravity and eigenvalues analysis under distributed loading, use of surfaceLoad automatism
- ex5.scd: complete 3D nonlinear fiber frame structure, with distributed plasticity, gravity, eigenvalues and pushover analysis
- utils_2.py: Python file for assigning GJ to fiber sectionsRead more
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#W4 |
Wed June 16, 2021
Geometries, Interactions, Selection Sets, and Local Axes
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Geometries, Interactions, Selection Sets, and Local Axes...
Geometries in STKO and OpenSees:
- Modeling geometries in OpenSees
- CAD Tools in STKO
- Concept of BRep vs orphan mesh
- Work tree geometry visualization
- Specific commands: wire, merge, compound, sew faces, etc...
- Query geometries
Interactions in STKO and OpenSees:
- Interaction definition
- How are interactions computed inside OpenSees (mention of constraints handler)
- Retained/constrained nodes concepts
- Implementation of interactions in STKO
Selection Sets:
- creation, update, use of this multipurpose tool
Local Axes:
- default assignment of local axes in STKO
- Reverse and Make Coherent commands
- geometric transformation in OpenSees
Prerequisites:
-Concepts of FEM
- Week 1 - Introduction to OpenSees
- Week 2 - Introduction to STKO
- Week 3 - Model Definition Overview
Materials and Resources:
- Powerpoint presentation
- Common errors webinar link
- ex6.scd: geometry example in STKO
- ex6.tcl: same geometry as for example 6 in tcl
- ex7.scd: support for different typologies of joint geometries
- utils_4.py: utility to build a geometry in STKO through the Python API
- utils_5.py: utility to find and select columns in a model with the wrong orientationRead more
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#W5 |
Wed June 23, 2021
Physical Properties
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Physical Properties...
- What is a physical property?
- How to create and assign a physical property? (material/section/integration scheme) - differences compared to SA software
- Materials (what are uniaxial materials, modeling concrete, steel, and masonry)
- Sections (Elastic, Fiber, Aggregator, RectangularFiber)
- Special purpose (BeamSectionProperty, HingedBeam, RCJointModel3D, MasonryInfillWallMaterial, zeroLengthMaterial, truss)
- Implementation
Prerequisites:
- Concepts of FEM
- Week 1 - 4
Materials and Resources:
- Powerpoint presentation
- ex8.scd: 3D concrete frame structure, nonlinear gravity analysis with fiber sections
- ex8.Tcl: Same as ex8.scd in tcl
- utils_5.py: Python script to assign properties to an existing X-Object
Read more
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#W6 |
Wed June 30, 2021
Element Properties
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Element Properties...
- What is an element property?
- Creation and assignment
- elasticBeamColumn
- forceBeamColumn
- displacementBeamColumn
- zeroLength elements
- hingedBeams
- truss elements
Prerequisites:
- Concepts of FEM
- Week 1 - 5
Materials and Resources:
-Powerpoint presentation
- ex.9 scd - softening and mesh objectivity
- ex10.scd - regularized results
- ex11.scd - beam column with no shear
- ex12.scd - beam column with shear
- ex13.scd - element loads example
- ex14.scd - modelling approaches example (not discussed, extra)
- ex9.spd - results from ex9 and ex10 already post processed
- utils_6.xls - Energy regularization spreadsheet
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#W7 |
Wed July 7, 2021
Definitions and Conditions
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Definitions and Conditions...
Definitions:
- concept of timeSeries
- concept of time in OpenSees
- types of timeSeries
Conditions:
- Constraints: single point and multi point constraints in STKO and OpenSees (fix, equalDOF, rigidDiaphragm and rigidLink)
- Loads: NodalLoads and ElementalLoads
- Masses
Prerequisites:
- Concepts of FEM
- Week 1 - 6
Materials and Resources:
Powerpoint presentation
- ex15.scd: axial release to avoid axial strain formation in fiber section due to the application of rigidDiaphragm multi-point constraints
Read more
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#W8 |
Wed July 14, 2021
Mesh and Analysis
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Mesh and Analysis...
Meshing:
- How to Mesh
- Global, edge, and remove seed
- Mesh controls
- Partitioning
Analysis:
- How to set up an analysis
- Relevance of the order
- Record command explained in detail
- Adding constraints
- Adding loads
- Default options
- CustomScript
- Region
- Rayleigh damping
Prerequisites:
- Concepts of FEM
- Week 1 - 7
Materials and Resources:
Powerpoint presentation
Read more
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#W9 |
Wed July 21, 2021
Analyses Command (Part 1 and 2)
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Analyses Command (Part 1 and 2)...
- Constraint handlers
- Numberers
- System solvers
- Convergence tests
Solution algorithms:
- Meaning
- Types
- Most common combinations
Prerequisites:
- Concepts of FEM
- Week 1 - Introduction to OpenSees
- Week 2 - Introduction to STKO
- Week 3 - Model Definition Overview
- Week 7 - Definitions and Conditions
- Week 8 - Mesh and Analysis
Materials and Resources:
Powerpoint presentation
Read more
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#W10 |
Wed July 28, 2021
Analyses Command (Part 3 and 4)
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Analyses Command (Part 3 and 4)...
- Static and transient integrators
- Aanalyze
- LoadConst
- WipeAnalysis
Typical analysis steps setup:
- Linear and nonlinear static analysis
- Pushover analysis
- Eigenvalue and response spectrum analysis
- Linear and nonlinear dynamic analysis
- Construction stage analysis
Prerequisites:
- Concepts of FEM
- Week 1 - Introduction to OpenSees
- Week 2 - Introduction to STKO
- Week 3 - Model Definition Overview
- Week 7 - Definitions and Conditions
- Week 8 - Mesh and Analysis
- Week 9 - Analyses Command (Part 1 and 2)
Materials and Resources:
Powerpoint presentation
Read more
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#W11 |
Wed August 4, 2021
Postprocessor, Visualizing Results
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Postprocessor, Visualizing Results...
The post-processor interface:
- Loading one or more databases
- Create and modify plots
- Chart data extraction and editing
- Exporting animations
- Tips and tricks to help you best view your model
Prerequisites:
- Concepts of FEM
- Week 1 - 10
Materials and Resources:
Powerpoint presentation
We were unable to load the .spd file from Week11 class, given the large size of the recorder databases. You can recreate the same result visualization by running the .scd files from Week 3, ex4.scd and ex5.scd. If you have any questions please do post them on our forum!
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#W12 |
Wed September 1, 2021
Linear Static Analysis
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Linear Static Analysis...
Modelling of a steel frame structure from scratch, learn to:
- Construct the geometry
- Define and assign physical and element properties
- Apply loads and boundary conditions
- Complete a linear static horizontal analysis
The class uses the same structure from ex4.scd explained in detail with the addition of truss elements to model braces, numerous scripts to automate calculations through the Python API and definitions of load combinations for specific limit state analysis.
Prerequisites:
- Concepts of FEM
- Week 1 - Week 11
Materials and Resources:
- Powerpoint presentation
- ex16.scd - Linear Elastic Analysis of a 3D Frame Steel Structure
- utils_7.py - Script to draw points at specific coordinates
- utils_8.py - Script to set up your units
- utils_9.py - Script to calculate material properties
- utils_10.py - Script to assign offset to all beams equal to half of the height of the section
- utils_11.py - Script to select all geometry to which a specific property is assigned
- utils_12.py - Script to assign mass and self weight to all beams with a specific physical property
- utils_13.py - Script to add a list of load conditions to a loadPattern
- utils_14.py - Script to create a loadCombination as a virtual result
- utils_15.py - Script to create an envelope of combinations (max, min)
Read more
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#W13 |
Wed September 8, 2021
Material and Geometric Nonlinearities (RC Structures)
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Material and Geometric Nonlinearities (RC Structures)...
- How to introduce material and geometric nonlinearities into a frame structure
- Definitions of appropriate material, sections, and elements to model concrete, steel, and masonry.
Prerequisites:
- Concepts of FEM
- Week 1 - Week 12
Materials and Resources:
-Powerpoint presentation
- ex17.scd: small frame structure, for comparison Linear and Corotational geometric transformation.
Read more
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#W14 |
Wed September 15, 2021
Modeling Approaches to Plasticity (RC Structures)
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Modeling Approaches to Plasticity (RC Structures)...
Modeling approaches to plasticity in 3D frame structures:
- Distributed plasticity
- Lumped plasticity in a finite-length element
- Lumped plasticity in a zero-length
The webinar will reference week 6's class on softening and mesh objectivity
Prerequisites:
- Concepts of FEM
- Week 1 - Week 13
Materials and Resources:
- Powerpoint presentation
- ex18.scd
- ex19.scd
- ex20.scd
- ex21.scd
- utils_17.xlxs
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#W15 |
Wed September 22, 2021
Nonlinear Static (Pushover) Analysis
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Nonlinear Static (Pushover) Analysis...
Nonlinear static pushover analysis in OpenSees with STKO:
-Definition of lateral force distribution patterns, mass proportional, and modal proportional
- Analysis setup
- Results plot
- Sensitivity analysis varying some model parameters
Prerequisites:
- Concepts of FEM
- Week 1 - Week 14
Materials and Resources:
- Powerpoint presentation
- ex22.scd - 3D frame structure, subject to pushover analysis with triangular lateral load distribution and brought to post peak behaviour.
- ex23.scd - 3D frame structure, subject to pushover analysis with modal proportional load distribution
- ex24.scd - 3D frame structure, subject to pushover analysis with mass proportional load distribution
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#W16 |
Wed September 29, 2021
Nonlinear Dynamic (Time History) Analysis
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Nonlinear Dynamic (Time History) Analysis...
- Definition of mass and damping
- Use of UniformExcitation or MultiSupport Excitation
- Transient analysis type setup
Prerequisites:
- Concepts of FEM
- Week 1 - Week 15
Materials and Resources:
- Powerpoint presentation
- ex25.scd - 3D frame structure NLTH with uniformExcitation
- ex26.scd - 3D frame structure NLTH with multiSupportExcitation
Read more
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#W17 |
Wed October 6, 2021
Modal Analysis and Response Spectrum
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Modal Analysis and Response Spectrum...
Modal and response spectrum analysis in OpenSees with STKO:
- Modal and response spectrum analysis in OpenSees with STKO:
- Eigen command and solvers
- Analysis setup, options, and requirements
- Visualization of results in the postProcessor
Prerequisites:
- Concepts of FEM
- Week 1 - Week 16
Materials and Resources:
- Powerpoint presentation
- ex27.scd - 3D frame structure, eigen analysis, modal properties calculation, and response spectrum analysis
- utils_18.py - modal combination of response spectrum analysis results
Read more
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#W18 |
Wed October 13, 2021
3D Frame Structures (Part 1) RC: diaphragms, joints, infill panels
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3D Frame Structures (Part 1) RC: diaphragms, joints, infill panels...
RC frame structure modelling applications:
- Rigid and flexible diaphragms
- Joint modeling
- Infill panels
Prerequisites:
- Concepts of FEM
- Week 1 - Week 17
Materials and Resources:
- Powerpoint presentation
- ex30.scd - 3D frame structure with flexible diaphragms
- ex31.scd - 3D frame structure with flexible diaphragms and infill modelled as trusses
- ex32.scd - 3D frame structure with rigid diaphragms
- ex33.scd - 3D frame structure with rigid diaphragms and RC joints
- 2014DeRisi.pdf - reference for calculations of RC joint constitutive law
- utils_19.py - calculations for the RCJoint constitutive law
Read more
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#W19 |
Wed Oct 20, 2021
3D Frame Structures (Part 2) - Steel: bracings, large displacements
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3D Frame Structures (Part 2) - Steel: bracings, large displacements...
Steel frame structure modeling applications:
- Steel sections (customization and alignment)
- Bracing
- Large displacement with geometric nonlinearities
Prerequisites:
- Concepts of FEM
- Week 1 - Week 18
Materials and Resources:
- Powerpoint presentation
- ex34.scd - 3D steel frame structure with unconnected bracing and rigid joints - NLTH analysis
- ex35.scd - 3D steel frame structure with unconnected bracing and uncoupled rotations in bracing ends - NLTH analysis
- ex36.scd - 3D steel frame structure with connected bracings - Pushdown with linear geometric transformation
- ex37.scd - 3D steel frame structure with connected bracings - Pushdown with nonlinear corotational geometric transformation
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#W20 |
Wed Oct 27, 2021
3D Frame Structures (Part 3) - Masonry: EFM of trilite and masonry walls
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3D Frame Structures:...
Masonry 3d frame structures, equivalent frame model applications:
- Trilite
- Masonry Walls
Prerequisites:
- Concepts of FEM
- Week 1 - Week 19
Materials and Resources:
- Powerpoint presentation
- ex38.scd - 3D masonry trilite structure with distributed plasticity approach and section aggregator for the inclusion of shear
- ex38bis.scd - 3D masonry trilite structure with distributed plasticity approach and beamWithShearHinges element for integration of the shear behaviour
- ex39.scd - 3D masonry trilite structure with lumped plasticity approach (finite length), inclusion of shear, bending, and axial behaviour
- ex40.scd - 3D masonry wall structure, with distributed plasticity approach
Read more
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