trussx

Utilities for building and analysing pin-jointed truss structures. The crate provides a small, strongly-typed API for creating joints and members, applying loads and supports, and running a linear elastic analysis in three dimensions.

Installation

Add the dependency to your Cargo.toml:

[dependencies]
trussx = "0.2"

Usage

use trussx::{force, point, Truss};

fn main() -> Result<(), Box<dyn std::error::Error>> {
    // Create a new truss structure
    let mut truss = Truss::new();

    // Define joints
    let a = truss.add_joint(point(0.0, 0.0, 0.0));
    let b = truss.add_joint(point(1.0, 0.0, 0.0));

    // Apply supports and loads
    truss.set_support(a, [true, true, true])?;
    truss.set_support(b, [false, true, true])?;
    truss.set_load(b, force(-1000.0, 0.0, 0.0))?;

    // Define member between joints
    let ab = truss.add_member(a, b);

    // Member properties must be strictly positive to represent a physical bar.
    truss.set_member_properties(ab, 0.01, 200.0e9)?;

    // Run the analysis and unwrap the result
    truss.evaluate()?;

    // Retrieve and print the displacement at joint B
    let displacement = truss.joint_displacement(b).unwrap();
    println!("ux = {:.3e} m", displacement.x);
    Ok(())
}

Both the cross-sectional area and elastic modulus must be strictly positive. The library rejects zero or negative inputs with a descriptive TrussEditError so incorrect data is surfaced before attempting an analysis.

Testing

The project includes unit tests that validate the analysis results for a simple bar in tension and ensure meaningful error reporting when required data is missing. Run the full suite with:

cargo test

Member safety factors

Assign a yield strength to each member with set_member_yield_strength to enable factor of safety calculations. During Truss::evaluate the library compares the absolute yield strength to the absolute axial stress for each analysed member and stores the ratio. You can read the value back with member_factor_of_safety.

member_factor_of_safety returns None when:

• No yield strength has been assigned to the member.
• The structure has not been analysed since the last modification.
• The computed axial stress is effectively zero (no meaningful demand).
• The resulting ratio is not a finite floating-point number.

The repository includes an executable example that demonstrates the workflow end-to-end:

cargo run --example factor_of_safety

See examples/factor_of_safety.rs for the full source. The integration tests under tests/ mirror the same cantilever scenario to provide executable documentation for the API without requiring a standalone CLI.