ENGR 2120H: Honors Project

This was my submission for the Spring 2024 ENGR 2120H honors project: a Rust program to analyse a 2D truss and solve for the force each member is under. In the time since submitting, I've worked on the project a fair ammount, and the current version is somewhat different than the original submission. Please see the tagged commits for the versions that I originally submitted.

Using the Program:

This program takes in a .toml file describing a 2d truss in static equilibrium. It will then solve for unknown forces and display the results (either in the terminal or to a text file). This program is intended to be invoked & run from the command line, as such it supports a few command-line options:

• The last item is optionally a path to a .toml file to solve
• '--quiet' will disable debug output information
• '-v' or '--verbose' will enable debug output information
• '-e' or '-e=<1, 2, or 3>' will display an example problem
• '-g' will display a simple drawing of the truss, its supports, and the applied loading.

Solver Expectations & Solving Strategy:

This project uses the method of joints to solve a two-dimensional truss in static equilibrium. Conceptually it creates a series of linear equations from the free-body diagrams of each joint in the truss. These equations are then combined into matrix form and solved with linear algebra.

These 'free-body diagrams' are represented in the TrussJoint2D structs, which are created in the Truss2D::condense() method. These are turned into equations (and ultimately a matrix equation) in the build_equations() and solve_truss() functions (found in solver.rs).

Creating a TOML file to solve a program

See template.toml for how to create a valid TOML file. I've tried to add useful error messages where possible, so it's hopefully not too difficult to fix issues if they pop up. You can also look in sample-problems for some examples. A few things to keep in mind:

• The program does not support units, so make sure that everything (e.g. applied loads, distances) are consistent.
• Angles are all measured in degrees.
• There are currently no checks to make sure a truss is actually in equilibrium, answers will be wrong if it's not.
• Check for typos and duplicate points / loads from copy-pasting, especially if you use an example file.

Updates

This has long since been submitted and graded, so I'm mostly adding things as I feel like and/or get bored. I don't really have any major plans for what this program will be, so yeah. So far I've added:

• Visualizing a truss
• Command line flags for different behavior
• Rewrote the code to parse a truss (w/ arguably no difference in functionality)
• Ended up removing the old parsing code (so only the solver is what I originally submitted)

Building & Running

Exactly what you'd expect for a rust project. Assuming you have rustup, run with cargo run. File paths for inputs are relative to the executable. It might take a sec for the dependencies to download / compile the first time you run it (Sorry, linear algebra libraries are hard to make & drawing to the screen is worse).

License

All rights reserved. Please do not use for training LLMs or generative AIs