The OpenSees Twitter bot started in December 2019 but didn't "like and retweet" #OpenSees tweets retroactively. So, out of curiosity, I searched Twitter the other day for the first use of the #OpenSees hashtag. This tweet from 2011 came up as the winner: https://twitter.com/drescolano/status/45099760868274176 Not an uncommon sentiment. Now, ten years later, I asked David … Continue reading It’s a Fine Line
Tcl as a Front End for Python
I know I'm not the only one who enjoys converting between scripting languages or between structural analysis programs. I've had fun writing bespoke Tcl middleware between OpenSees and MATLAB, but now OpenSeesPy makes all of that obsolete. But, let's say you have an OpenSees Tcl script that you'd like to run in OpenSeesPy. There's a … Continue reading Tcl as a Front End for Python
There’s Three, Actually
The displacement-based and force-based formulations garner a lot of comparisons for simulating nonlinear frame response. My Google Scholar alerts tell me so. And I even wrote a post comparing the two formulations. Doc Ock from Spider-Man: Into the Spider-Verse There is a third formulation--the mixed formulation. Alemdar and White compared three frame element formulations (displacement-based, … Continue reading There’s Three, Actually
Random Bullets on Blogging
It's 2021. So, why blog when peak blogging was like 2007? Here are some random bullets on why blogging works for me. The more you write, the more ideas you generate. Usually it's ideas for more blog posts, but sometimes it's new ideas for research.Blog posts have a direct, conversational tone. Like I'm talking with … Continue reading Random Bullets on Blogging
The Rayleigh Quotient
Eigenvalue analysis wasn't giving me what I wanted the other day. So, to make a long story short, I decided to try Rayleigh's method. I won't go through all the details of Rayleigh's method, but the basic idea is you can obtain a very good approximation of the fundamental frequency of a structural model by … Continue reading The Rayleigh Quotient
Discretized Members Only
I wrote a DiscretizeMember procedure in Tcl many years ago--I don't know exactly when, definitely after the 1980s and definitely before moving to Eastchester. "Members Only." by The Semi-Frozen Trombone is licensed under CC BY 2.0 After carrying the function around for years, and probably spawning more variations than uniaxial Concrete models, the procedure went … Continue reading Discretized Members Only
Go Cite Yourself
Metric-driven academia, with its focus on h-indices and impact factors, has led to shady behaviors like citation cartels and publication bounties. Superfluous self-citations are also shady, but a few self-citations are natural when developing a line of research. So, go ahead and post a selfie. https://twitter.com/mikusscott/status/975382276434378752 Think of the baristas at your local coffee shop. … Continue reading Go Cite Yourself
Right Under Your Nose
I long ago accepted that buckling analysis would never be implemented in OpenSees. Although there is a getGeometricTangentStiff() method in the Element interface, only PFEM fluid elements use it. Implementing this method for frame elements, assembling the geometric stiffness, and solving the generalized eigenvalue problem would require several updates to the innards of OpenSees. Then … Continue reading Right Under Your Nose
Going Through Stages
Most structural earthquake engineering deals with staged analyses of built infrastructure in one way or another. In the most common scenario, we apply gravity loads to a structural model, get the model in equilibrium, then simulate the model response to earthquake loading. Analysis of structural systems and components during construction is also important. Temporary construction … Continue reading Going Through Stages
Backlink Hijinks
The OpenSees message board is kind of a mess. Not due to posters, responders, or moderators, but because of the huge amount of spam posts. I've seen various forms of message board spam including offers for cell phone numbers, online games, and refrigeration equipment, as well as some spam that's NSFW. Removing all the spam … Continue reading Backlink Hijinks
Portwood Digital 