Minimal Thermal Example

For verification purposes, I needed to come up with the fixed-end axial force for a beam subjected to uniform thermal expansion. It's not rocket science, nowhere near an LPU, but a little pencil and paper and the free end axial deflection is $latex \alpha (\Delta T) L$. The fixed-end axial force, to push the free … Continue reading Minimal Thermal Example →

Projectile OpenSeesing

Growing up in the Pine State, you were either a fan of NASCAR or college basketball, and in some cases both. I leaned heavily toward the latter. The hard dynamics underpins the physics of both sports--and most others. Centripetal forces act on race cars going around turns and projectile motion is a simplified description of … Continue reading Projectile OpenSeesing →

How to Use with with OpenSeesPy

The with command offers a clean approach to manage Python resources, particularly file streams. Without going into detail, the with command is a shortcut for exception handling. The nice thing about reading and writing files using the with command is you don't have to worry about closing the file stream. Immediately after the with block … Continue reading How to Use with with OpenSeesPy →

No Element Required

Simulating basic particle motion raises subtle, often overlooked points about OpenSees. For example, consider problem 12-1 from Hibbeler's Engineering Mechanics: Dynamics, 14th edition. A particle moves along a straight line with acceleration a=(2t-6) m/s2. What is the velocity at t=6 s and displacement at t=11 s? Assume at rest initial conditions. By integration, the exact … Continue reading No Element Required →

The Hard Dynamics

I am confident that you can use OpenSees to solve all reasonable problems from textbooks on statics, structural analysis, finite elements, structural dynamics, and (most of) strength of materials. But what about engineering dynamics? The rigid body dynamics that's way more difficult than deformable body dynamics. You know, kinematics and kinetics of particles and rigid … Continue reading The Hard Dynamics →

2023 In Review

WordPress put together a year-in-review summary of blog statistics, but the automated report had a couple errors--namely reporting that April 24, 2023 accounted for 817% of all blog visits for the year and that the high number of referrals from Facebook was "a nod to our [WordPress's] targeted SEO and marketing efforts." Despite the error … Continue reading 2023 In Review →

A Better Way to Find Memory Leaks in OpenSees

In a previous post, I explained how to find a memory leak in OpenSees. The basic idea was to put the analysis inside a loop, run the loop a million times, and monitor your operating system for increasing memory usage. A perfectly fine leak hunting approach--as long as you are willing to monitor your operating … Continue reading A Better Way to Find Memory Leaks in OpenSees →

Good Scotch

In the "I believe..." monologue from Bull Durham, Crash Davis (Kevin Costner) states his beliefs on various subjects, many of which prove the movie was about more than baseball. In fact, some of the beliefs refer to OpenSees. With "high fiber", Davis reveals his preference for fiber sections. And "hanging curve ball" clearly describes IDA … Continue reading Good Scotch →

Edit Your Copy

There's more to publishing a journal article--or any other content you want to unleash on the world--than writing some words, accepting all spell check corrections, and running your favorite AI-powered grammar checker. From conception to preservation on a virtual shelf, your journal article should go through at least five stages of editing--most stages more than … Continue reading Edit Your Copy →

Eccentrically Loaded Bolt Groups with Bolt Hole Clearance

Standard bolt holes punched in steel elements are either 1/16 inch or 1/8 inch wider than the bolt diameter. Oversized bolt holes can have larger clearances in order to make fit-up easier. While the bolt hole clearance can affect the available strength of an eccentrically loaded bolt group, Tables 7-6 to 7-13 of the AISC … Continue reading Eccentrically Loaded Bolt Groups with Bolt Hole Clearance →