Long before structural fire analysis became an OpenSees side hustle, the elasticBeamColumn element was able to handle thermal loads. The -alpha and -depth options are not really Easter eggs so much as undocumented features. Back in 2002, when OpenSees source control used CVS, Scott Hamilton modified the elasticBeamColumn element with two optional parameters for the coefficient of thermal expansion and beam depth. He also defined Beam2dTempLoad to apply temperatures … Continue reading Thermal Loads on an Elastic Beam
Tag: Beam
Partial-Span Uniform Loads
Although no one is going to use OpenSees to compute tributary loads for one-way floor systems, it’s still satisfying to analyze the resulting beam models. A common example is a beam that frames around one side of a floor opening. On the side of the beam with no opening, tributary area calculations produce a uniform … Continue reading Partial-Span Uniform Loads
Distributed Moments
I have often posited that we can use OpenSees to solve every reasonable problem from any textbook on structural analysis, dynamics, or mechanics. I even put together a few posts, e.g., here and here, on how OpenSees can solve rigid body dynamics problems, the ones that torment every civil engineering sophomore. But a seemingly easy structural analysis problem that OpenSees … Continue reading Distributed Moments
How to Mesh Shells
If you have created a mesh of planar (2D) elements in OpenSees, creating a mesh of shell elements (3D) is not that different. You can use either the block2D command or Minjie's line and mesh commands. However, you will quickly find that the block2D command--2D because the mesh is planar, not because the command is … Continue reading How to Mesh Shells
Elastic Shear Beams in OpenSees
Shear deformations in slender beams are generally not significant compared to flexural deformations. But shear deformation are important in deep beams and short walls, and flexure-shear interaction may be important in the material nonlinear range of response, regardless of aspect ratio. Enough of the perfunctory, non-committal language--you can find that in the latest issue of … Continue reading Elastic Shear Beams in OpenSees
Trapezoidal Beam Loads
OpenSees will never win any awards for documentation. Although many features, e.g., Concrete23, are not documented because no one uses them, a few useful items lack documentation. For instance, did you know that you can apply trapezoidal member loads to beam elements? You can do so with additional arguments to the eleLoad command with the … Continue reading Trapezoidal Beam Loads
How to Bend Beams
How to Boil Water was one of the first cooking shows on the Food Network. Emeril Lagasse was the original host and the show was geared toward people with little to no cooking experience. Everyone starts as a beginner. I was no exception when learning OpenSees. But when I'm asked where's the best place to … Continue reading How to Bend Beams
Most Solvers Can Be Marplots
Have you ever tried to replicate the familiar beam stiffness coefficients $latex 12EI/L^3$, $latex 6EI/L^2$, $latex 4EI/L$, and $latex 2EI/L$ (there's a poem about them here) by imposing unit displacements and rotations at fixed supports? It should be one of the first sanity checks you make when using or developing new structural analysis software. You … Continue reading Most Solvers Can Be Marplots