OpenSees Digital

OpenSees AMI

OpenSees Digital is the future-proof Portwood Digital twin.

The verification examples, white noise tests, and examples from each post, some of which are also verification, are re-generated once a week via a GitHub Action with the most up-to-date OpenSees source code.

As OpenSees evolves, so may the results shown on this site.

389 posts ported.

Posts

Feb 15, 2025
Textbooks and Hand Grenades
Feb 9, 2025
Damping Is a Sensitive Subject
Jan 26, 2025
Which Noun Are You Modifying?
Jan 19, 2025
One Fiber at a Time
Jan 12, 2025
Minimal Damper Example
Jan 5, 2025
J2 Plasticity Parameters
Dec 31, 2024
2024 In Review
Dec 22, 2024
How to Profile an OpenSeesPy Analysis
Dec 11, 2024
Invertible Does Not Mean Stable
Dec 1, 2024
Beyond OpenSees
Nov 27, 2024
See You in December
Nov 26, 2024
A Simple Base-Isolated Model
Nov 25, 2024
Getting the Number of Nodal DOFs
Nov 24, 2024
Long Term Column Loading
Nov 23, 2024
OpenSees Tom Swifties
Nov 22, 2024
The Maximal Broken Example
Nov 21, 2024
Dangling Recorders
Nov 20, 2024
No Reaction
Nov 19, 2024
The Old Code OpenSees
Nov 18, 2024
Sequential Ground Motions
Nov 17, 2024
Getting the Digits
Nov 16, 2024
Critical Buckling Loads via CBDI
Nov 14, 2024
The Good, the Not So Bad, and the Full General
Nov 13, 2024
Hydrostatic Loading on a Wall
Nov 12, 2024
OpenSees Mandela Effect
Nov 11, 2024
Corotational Rigid Offsets
Nov 10, 2024
A Return to FORM
Nov 9, 2024
The Sound of "OpenSees"
Nov 8, 2024
Plate Rebar Material
Nov 7, 2024
Show Me Don't Tell Me
Nov 6, 2024
OpenSees Retractions
Nov 5, 2024
Is It Close Enough?
Nov 4, 2024
A Load at a Fixed DOF
Nov 3, 2024
Sloshing Around
Nov 2, 2024
OpenSees Every Day
Nov 1, 2024
Torsional Buckling
Oct 27, 2024
A Post from ChatGPT
Oct 13, 2024
Set and Get Concrete23 Response
Oct 6, 2024
All About Making that ZPA
Sep 29, 2024
Valid Range of OpenSees Tags
Sep 2, 2024
Murum, cura te ipsum
Aug 18, 2024
Secant Accelerated Newton Algorithm
Aug 8, 2024
Just Fillin' Up the Tank
Jun 28, 2024
The OpenSees WCEE Bump
Jun 23, 2024
The Toy Reliability Problem
Jun 10, 2024
Earthquake Engineering Experts Hate Me for This One Weird Trick
Jun 2, 2024
Effective Earthquake Forces
May 23, 2024
OpenSees Bean Counting
May 19, 2024
Wrapper's Delight
May 16, 2024
Is OpenSees Pythonic?
Apr 21, 2024
Material Testing with White Noise
Mar 24, 2024
OpenSees Command Line Arguments
Mar 10, 2024
It Hides in Plain Sight
Feb 21, 2024
Spreader Beam Analysis
Feb 14, 2024
Faux Contact Sport
Feb 10, 2024
Two Sprung Masses and Some Friction Force
Jan 28, 2024
Centripetal Acceleration
Jan 24, 2024
Minimal Thermal Example
Jan 21, 2024
Projectile OpenSeesing
Jan 17, 2024
How to Use with with OpenSeesPy
Jan 14, 2024
No Element Required
Jan 7, 2024
The Hard Dynamics
Dec 31, 2023
2023 In Review
Dec 27, 2023
A Better Way to Find a Memory Leak in OpenSees
Dec 24, 2023
Good Scotch
Dec 17, 2023
Edit Your Copy
Dec 10, 2023
Eccentrically Loaded Bolt Groups with Bolt Hole Clearance
Nov 30, 2023
Beam With Hinges Interior Redux
Nov 29, 2023
What Is a Good Penalty Number?
Nov 28, 2023
The Sensitivity Is in the Details
Nov 27, 2023
Making a Point Load
Nov 26, 2023
How to Apply Ground Motions in Multiple Directions
Nov 25, 2023
Will OpenSees Ever Be Un-Seen?
Nov 24, 2023
Rectangular Hollow Structural Sections
Nov 23, 2023
Cheesy OpenSees Jokes
Nov 22, 2023
It Takes Two
Nov 21, 2023
Losing Displacement Control
Nov 20, 2023
Could Not Invert Element Flexibility
Nov 19, 2023
An Ode to Concrete23
Nov 18, 2023
One and Only One
Nov 17, 2023
Section Integration
Nov 16, 2023
Life of OpenSees Pi
Nov 15, 2023
How to Mesh Shells
Nov 14, 2023
Distributed Mass Beam Vibration
Nov 13, 2023
It's OK to Be Negative
Nov 12, 2023
Flipping Rotation Axes
Nov 11, 2023
Tuned Damper Models
Nov 10, 2023
Right, then Left
Nov 9, 2023
Handling a Doubt
Nov 8, 2023
Pleasing the Compiler
Nov 7, 2023
Constraint Matrix Not Identity
Nov 6, 2023
The PFEM in OpenSees
Nov 5, 2023
Do It Your Self-Weight
Nov 4, 2023
Make Every Word Count
Nov 3, 2023
Something Like a Double Negative
Nov 2, 2023
You Never Forget
Nov 1, 2023
How to Apply a Pulse Ground Motion
Oct 31, 2023
Will Write for OpenSees
Oct 29, 2023
Beware the Em Dash
Oct 22, 2023
Minimal DDM Examples
Oct 8, 2023
Converging to Something
Sep 24, 2023
Minimal GimmeMCK Example
Sep 14, 2023
Silence Is Golden
Aug 20, 2023
The Three Node Quad
Aug 14, 2023
Hidden Fees
Aug 13, 2023
Transformation Cross-Training
Jul 31, 2023
Minimal Plotting Example
Jul 16, 2023
Cargo Cult OpenSeesing
Jul 9, 2023
Concrete Zero
Jun 14, 2023
What Does It Refer To?
Jun 4, 2023
Runnin' Down a Leak
May 28, 2023
Minimal Creep and Shrinkage Example
May 16, 2023
How to Keep Your OpenSees Code Private on GitHub
May 14, 2023
Abstract Frenzy
May 2, 2023
Arc Length Parameters
Apr 2, 2023
A Rigid Bar Walks Into a Bar
Mar 19, 2023
My Favorite Ternary Operation
Mar 14, 2023
How to Bend Beams in 3D
Mar 12, 2023
Pity the Reader
Mar 1, 2023
Shutting Off the Containment Unit
Feb 12, 2023
Not Everything Should Be a Direct Translation
Feb 5, 2023
Pruning OpenSees
Jan 25, 2023
Modal and Stiffness Proportional Damping
Jan 16, 2023
Eigenvalues of the Stiffness Matrix
Jan 9, 2023
How to Use Block2D
Jan 2, 2023
Two Thousand Concrete23!
Dec 17, 2022
Eccentrically Loaded Bolt Groups
Nov 30, 2022
On OpenSeesing Well
Nov 29, 2022
More Ado About Damping
Nov 28, 2022
Sometimes Tags Don't Matter
Nov 27, 2022
OpenSees Smarter, Not Harder
Nov 26, 2022
A Simple Material Tester
Nov 25, 2022
Multi-Threaded SDF Analysis
Nov 24, 2022
Bad OpenSees Turkey Jokes
Nov 23, 2022
I Missed Again
Nov 22, 2022
Writing that Shines
Nov 21, 2022
How to Profile OpenSees
Nov 20, 2022
Blogged Higher and Deeper
Nov 19, 2022
Top 5 Posts
Nov 18, 2022
Don't Invert the Matrix
Nov 17, 2022
Single Quotes or Double?
Nov 16, 2022
Stop Hogging All the RAM
Nov 15, 2022
Geometric Transformation
Nov 14, 2022
Don't Delete This Bot
Nov 13, 2022
Verbing OpenSees
Nov 12, 2022
Publish Your Age
Nov 11, 2022
Another Way to Get Bad Eigenvalues
Nov 10, 2022
One Way to Get Bad Eigenvalues
Nov 9, 2022
How to Find the Neutral Axis
Nov 8, 2022
Quick (and Dirty) Modal Damping
Nov 7, 2022
Pseudo-Time Is Not the Load Factor
Nov 6, 2022
Misalignment with OpenSees
Nov 5, 2022
Rigid Diaphragm for 2D Models
Nov 4, 2022
Simple Loads on a Cantilever
Nov 3, 2022
OpenSees Pareto Principles
Nov 2, 2022
Element Self-Weight
Nov 1, 2022
CyclopSees
Oct 23, 2022
A Lovely Little Mystery
Oct 9, 2022
Chekhov's Gun
Oct 2, 2022
OpenSeesPy List Comprehensions
Sep 18, 2022
The Basic Natural Kernel in a Corotating Frame of Reference
Sep 11, 2022
Unrolling the Four Node Quad
Sep 4, 2022
Un-Matlab Your OpenSees
Aug 28, 2022
El viejo y los mares abiertos
Aug 21, 2022
An OpenSeesSPecial Request
Aug 14, 2022
Parametric Oscillator
Aug 7, 2022
Main Street, OpenSees
Jul 31, 2022
A Nod to Backward Compatibility
Jul 24, 2022
Nonlinear Sections, Elastic Elements
Jul 17, 2022
Negative Feedback Loop
Jul 10, 2022
Shear Verse, Same as the First
Jul 3, 2022
Elastic Shear Beams in OpenSees
Jun 26, 2022
OpenSees 12345
Jun 19, 2022
A Simple Solution to a Complicated Equivalent
Jun 15, 2022
Full Fiber Circle
Jun 12, 2022
P-M Interaction by the Book
Jun 8, 2022
Get the Accel Out
Jun 5, 2022
Rectangular Patches
May 29, 2022
How to Find a Memory Leak in OpenSees
May 22, 2022
A Solution, Just Not The Solution
May 15, 2022
Plane Sections Do Remain Plane
May 8, 2022
Switching Sides
May 1, 2022
A Complicated Equivalent
Apr 24, 2022
Fuzzy Zero Length Logic
Apr 17, 2022
Hysteretic Damage Parameters
Apr 10, 2022
How to Record Section Curvature
Apr 3, 2022
Gimme All Your Modal Damping
Mar 20, 2022
Non-Convergence Is Not Structural Collapse
Mar 13, 2022
OpenSees Spy
Mar 6, 2022
More Than You or Eigen Chew
Feb 13, 2022
OpenSees Scattergories
Feb 6, 2022
Two Fibers Explain So Much
Jan 30, 2022
Much Ado About Damping
Jan 27, 2022
Major League
Jan 24, 2022
See the Convergence
Jan 16, 2022
Two Fibers Five Ways
Jan 12, 2022
Verifying Will Never Be Easy
Jan 9, 2022
The Stiffness Matrix Isn't Everything
Jan 3, 2022
Start Over Again
Jan 2, 2022
More Solutions Than Problems
Dec 26, 2021
OpenSees Tcl to Python Converter
Dec 19, 2021
Three-Dimensional Meshing
Dec 12, 2021
Glulam Volume Factor
Dec 5, 2021
Two Paths You Can Go By
Dec 1, 2021
NaBloPoMo Recap
Nov 30, 2021
Line Mesh
Nov 29, 2021
Two-Dimensional Meshing
Nov 28, 2021
Work on Your Cliches
Nov 27, 2021
Finite Differences
Nov 26, 2021
Full Credit
Nov 25, 2021
Happy Franksgiving
Nov 24, 2021
Tips for Squandering OpenSees
Nov 23, 2021
Earthquake Songs
Nov 22, 2021
Cable Analysis
Nov 21, 2021
Make a Pull Request
Nov 20, 2021
Initial Conditions
Nov 19, 2021
Monte Carlo Simulation
Nov 18, 2021
Means and Ends
Nov 17, 2021
Five Tweets from the Bot
Nov 16, 2021
Repeated Section Modes
Nov 15, 2021
Trying to Get a Reaction
Nov 14, 2021
RBOC: Influence Lines
Nov 13, 2021
Inerters Everywhere
Nov 12, 2021
OpenSeesaw
Nov 11, 2021
Your DLL Might Be Ignored
Nov 10, 2021
You Get What You Give
Nov 9, 2021
Eigenvalues During an Analysis
Nov 8, 2021
One Citation at a Time
Nov 7, 2021
Section X
Nov 6, 2021
Concrete02 with Control of the Initial Stiffness
Nov 5, 2021
You Didn't Build That
Nov 4, 2021
Slender Things
Nov 3, 2021
OpenSeesBf
Nov 2, 2021
Interpolation of Ground Acceleration
Nov 1, 2021
Don't Think, Just Throw
Oct 31, 2021
The Little IDA
Oct 26, 2021
Not All at Once
Oct 24, 2021
No Exit
Oct 17, 2021
Non-Prismatic Frame Elements
Oct 10, 2021
Failed to Get Compatible ...
Oct 3, 2021
Every OpenSees Tutorial
Sep 26, 2021
Direct Moment-Curvature
Sep 19, 2021
Like Spinning Nodes
Sep 12, 2021
Failure to Solve
Sep 7, 2021
A Blog in Motion
Sep 6, 2021
Non-Fungible OpenSees
Sep 5, 2021
RBOC for the Fall
Aug 29, 2021
Multiple-Support Excitation
Aug 22, 2021
Making Sense Out of Concrete02
Aug 15, 2021
Parameter Updates in the Loop
Aug 8, 2021
Nobody Wants to Read Your Shit
Aug 1, 2021
That's a Large Mass
Jul 26, 2021
Building Blocks
Jul 25, 2021
How to Record Fiber Response
Jul 18, 2021
Polymorphic Pitfall
Jul 15, 2021
Off the Hooke
Jul 11, 2021
Verifying Ain't Easy
Jul 5, 2021
Absolutely, It's Relative
Jul 4, 2021
You Gotta Keep 'em Aggregated
Jul 1, 2021
Minimal Working Example
Jun 27, 2021
It's a Fine Line
Jun 20, 2021
Tcl as a Front End for Python
Jun 13, 2021
There's Three, Actually
Jun 9, 2021
Random Bullets on Blogging
Jun 6, 2021
The Rayleigh Quotient
Jun 2, 2021
Discretized Members Only
May 30, 2021
Go Cite Yourself
May 29, 2021
Right Under Your Nose
May 26, 2021
Going Through Stages
May 23, 2021
Backlink Hijinks
May 19, 2021
Elastoplastic Calibration
May 16, 2021
Striking YouTube Gold
May 12, 2021
No Framework for Old Men
May 9, 2021
Reaction and Unbalance
May 5, 2021
Trapezoidal Beam Loads
May 2, 2021
Release the Plastic Hinge
Apr 28, 2021
Syllabus by Blogging
Apr 25, 2021
Heavy as a Chebyshev
Apr 21, 2021
How to Cite a Blog Post
Apr 18, 2021
Its Power and Its Problem
Apr 14, 2021
OpenSees Is Simple
Apr 11, 2021
Stress Resultant Verification
Apr 4, 2021
Did You Pass Your Patch Test?
Mar 28, 2021
Wind in Warped Sails
Mar 21, 2021
Wipe Out!
Mar 14, 2021
Plastic Rotation
Mar 7, 2021
Stability Challenge Results
Feb 28, 2021
Norms and Tolerance
Feb 21, 2021
Don't Try This at Home
Feb 14, 2021
How Many Clicks Does It Take?
Feb 7, 2021
It's Not Load Control
Jan 31, 2021
A Very Stable Challenge
Jan 24, 2021
Fiber Section Centroids
Jan 17, 2021
Nonlinear Elements, Elastic Sections
Jan 10, 2021
Load Patterns and Time Series
Jan 4, 2021
OpenSees Blog Delurking Week
Jan 3, 2021
Sensitivity Training
Dec 27, 2020
Hysteretic Pinching Parameters
Dec 22, 2020
Every Ending Is a New Beginning
Dec 13, 2020
When a Deal Breaker Is Not a Deal Breaker
Dec 9, 2020
Uniaxial Multi-Tool
Nov 30, 2020
OpenSees Fire v2.0
Nov 29, 2020
A Little Secret About OpenSees Tcl
Nov 28, 2020
The Linear Algorithm Strikes Again
Nov 27, 2020
Make Room for Storage
Nov 26, 2020
OpenSees Thanksgiving
Nov 25, 2020
OpenSees Facebook Group
Nov 24, 2020
Compiling OpenSees
Nov 23, 2020
Reduce Your Bandwidth
Nov 22, 2020
Moving and Influential
Nov 21, 2020
Twitter Bot 200
Nov 20, 2020
Mass and Weight
Nov 19, 2020
Rigid Joint Offsets
Nov 18, 2020
Fibers of Higher Dimensions
Nov 17, 2020
You Know You'll Have to Write About It
Nov 16, 2020
Brace Your Tcl Code
Nov 15, 2020
OpenSees Documentation
Nov 14, 2020
Last Committed Stiffness
Nov 13, 2020
Ordinary Eigenvalues
Nov 12, 2020
The Prevalence of OpenSees in JSE
Nov 11, 2020
PSA: OpenSees Commands Are Case Sensitive
Nov 10, 2020
A Quad Out West
Nov 9, 2020
Don't Forget to Take a Selfie
Nov 8, 2020
Rayleigh Damping Coefficients
Nov 7, 2020
Early Landscape of OpenSees
Nov 6, 2020
Variations on Modified Newton
Nov 5, 2020
Pushover with Constant Ground Jerk
Nov 4, 2020
OpenSeesPy Is Not Terrible for the Environment
Nov 3, 2020
How to Bend Beams
Nov 2, 2020
Force-Based Beam-Column Integration Options
Nov 1, 2020
Modal Participation Factors
Oct 29, 2020
NaBloPoMo 2020 - OpenSees Edition
Oct 25, 2020
The Basics of Frame Element Localization
Oct 12, 2020
Glenn Holcomb, The Prof.
Sep 30, 2020
Closing the Loop on Direct Assembly
Sep 13, 2020
Global Distributed Loads
Sep 7, 2020
Thoughts After a Year of Blogging
Sep 2, 2020
SSI Modeling Challenge Results
Aug 27, 2020
Most Solvers Can Be Marplots
Aug 21, 2020
A Marathon, Not a Sprint
Aug 14, 2020
Recorders not Recording?
Aug 8, 2020
A Vector in the x-z Plane
Jul 27, 2020
One Iteration of a Second Order Analysis
Jul 24, 2020
Discarded Wrappers
Jul 15, 2020
SSI Modeling Challenge
Jul 11, 2020
There's a Wrapper for That
Jul 3, 2020
Integration Points with Negative Weight
Jun 24, 2020
Where is Eastchester?
Jun 19, 2020
Results of a New Challenge
Jun 13, 2020
Not Just a Modeling Term
Jun 5, 2020
Handle Your Constraints with Care
May 17, 2020
Gimme All Your Damping, All Your Mass and Stiffness Too
May 10, 2020
Meshing for Column Loads
May 4, 2020
A New Challenge
Apr 21, 2020
More Is Not Always Better
Apr 12, 2020
Semi-Blind Kind of Contest Results
Apr 5, 2020
Close to the Edge
Mar 17, 2020
Better Late than Never
Mar 1, 2020
A Semi-Blind Kind of Contest
Feb 23, 2020
A Tale of Two Element Formulations
Feb 15, 2020
With or Without You
Feb 8, 2020
Better Than Ideal Conditions
Feb 2, 2020
Abstract Thoughts
Jan 31, 2020
Start with the Correct Static Resisting Force
Jan 25, 2020
Incompetence, Not Malice
Jan 19, 2020
Recognizable Dates as Self-Imposed Deadlines
Jan 8, 2020
Blog Delurking Week
Jan 5, 2020
The Fiber Content of OpenSees
Dec 26, 2019
OpenSees Twitter Bot
Dec 20, 2019
OpenSees Shells by the Seashore
Dec 15, 2019
Unretiring the String Class
Dec 8, 2019
An Update of the IMK Models
Dec 1, 2019
Algorithmic Limerick
Nov 24, 2019
Thankful for OpenSees
Nov 18, 2019
Just Another Python Module
Nov 11, 2019
OpenSees Time Machine
Nov 7, 2019
Only Their Mother Can Tell Them Apart
Nov 1, 2019
OpenSees Source Control: From Zip to Git
Oct 26, 2019
Gaming ResearchGate
Oct 23, 2019
Non-Convergence Does Not Mean OpenSees Crashed
Oct 19, 2019
One More OpenSees Analysis
Oct 12, 2019
Behind the Elastic Interior
Oct 6, 2019
Torsion with Fiber Sections
Oct 1, 2019
Be More Specific than "Fiber Element"
Sep 27, 2019
Is Plastic Hinge Integration a Fruit or a Vegetable?
Sep 22, 2019
How to Cite OpenSees
Sep 14, 2019
No CAPS When You Spell the Framework's Name
Sep 12, 2019
Be Careful with Modal Damping
Sep 7, 2019
Coming Soon