Your DLL Might Be Ignored

I am not a fan of DLLs (dynamic-link library) for material and element models in OpenSees. There are many technical reasons for my dislike of DLLs--fragile code, multiple versions swirling around online, keeping up to date with the latest OpenSees executable, debugging difficulty, and cross-platform compatibility to name a few. So, if you've published your … Continue reading Your DLL Might Be Ignored

Off the Hooke

To grasp nonlinear structural analysis, unlearn Hooke's Law, $latex \sigma = E\varepsilon$. And all derivative outcomes of Hooke's Law. Like $latex \kappa=M/EI$ and $latex {\bf K} {\bf U} = {\bf P}$. When steel yields, concrete cracks, etc., Hooke's Law no longer applies and holding on to it can lead to erroneous interpretations of nonlinear … Continue reading Off the Hooke

It’s a Fine Line

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: Not an uncommon sentiment. Now, ten years later, I asked David … Continue reading It’s a Fine Line

OpenSees Is Simple

OpenSees, and nonlinear structural analysis in general, is a simple endeavor. It is not complicated. It does not need to be complex. Although this clip from Bull Durham, the best baseball movie of all time, refers to throwing, hitting, and catching the ball, the simplicity translates to nonlinear structural analysis. You build the model. … Continue reading OpenSees Is Simple