Struct GeoNonlinearBar 

pub struct GeoNonlinearBar {
    pub ea: f64,
    pub length: f64,
}

A single-DOF geometrically-nonlinear axial bar (fixed–free), Green–Lagrange strain.

For a straight prismatic bar of length L, section EA, with the fixed end at x = 0 and axial tip displacement u, the Green–Lagrange axial strain is ε = u/L + ½(u/L)². Strain energy U = ½·EA·L·ε², so the internal tip force and its tangent are

• f_int(u) = EA·ε·(1 + u/L)
• Kₜ(u) = (EA/L)·[(1 + u/L)² + ε]

These reduce to the linear bar (f = EA·u/L) for small u and stiffen geometrically for large u. This is the concrete nonlinear model wired to the facade NonlinearStatic / NonlinearDynamic variants.

Fields

ea: f64

length: f64

Implementations

impl GeoNonlinearBar

pub fn strain(&self, u: f64) -> f64

Green–Lagrange axial strain at tip displacement u.

pub fn internal_force(&self, u: f64) -> f64

Internal tip force f_int(u).

pub fn tangent(&self, u: f64) -> f64

Tangent stiffness Kₜ(u).

pub fn solve_static( &self, f_ext: f64, tol: f64, max_iter: usize, ) -> Result<f64, EngineeringError>

Solve f_int(u) = f_ext for the tip displacement by Newton–Raphson.

Trait Implementations

impl Clone for GeoNonlinearBar

fn clone(&self) -> GeoNonlinearBar

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for GeoNonlinearBar

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Copy for GeoNonlinearBar