Struct ShapeMemoryAlloy 

pub struct ShapeMemoryAlloy {
    pub ms: f64,
    pub mf: f64,
    pub as_: f64,
    pub af: f64,
    pub e_austenite: f64,
    pub e_martensite: f64,
    pub h_max: f64,
}

Thermomechanical model of a shape memory alloy.

Transformation temperatures are in kelvin (K); stresses in pascal (Pa); elastic moduli in pascal (Pa); strains dimensionless.

The martensite fraction ξ ∈ [0, 1] describes the phase state:

• ξ = 1 → fully martensitic
• ξ = 0 → fully austenitic

Fields

ms: f64

Martensite start temperature (Ms) in K.

mf: f64

Martensite finish temperature (Mf) in K.

as_: f64

Austenite start temperature (As) in K.

af: f64

Austenite finish temperature (Af) in K.

e_austenite: f64

Elastic modulus of the austenite phase in Pa.

e_martensite: f64

Elastic modulus of the martensite phase in Pa.

h_max: f64

Maximum recoverable (transformation) strain ε_L (dimensionless).

Implementations

impl ShapeMemoryAlloy

pub fn new( ms: f64, mf: f64, as_: f64, af: f64, e_austenite: f64, e_martensite: f64, h_max: f64, ) -> Self

Create a new SMA model with the given transformation temperatures and elastic moduli.

Parameters

• ms – martensite start temperature [K]
• mf – martensite finish temperature [K]
• as_ – austenite start temperature [K]
• af – austenite finish temperature [K]
• e_austenite – austenite elastic modulus [Pa]
• e_martensite – martensite elastic modulus [Pa]
• h_max – maximum transformation strain

pub fn new_nitinol() -> Self

Create a standard Nitinol (NiTi) SMA with typical reported parameters.

• Ms = 291 K, Mf = 273 K, As = 307 K, Af = 325 K
• E_A = 75 GPa, E_M = 28 GPa, ε_L = 0.08

pub fn nitinol() -> Self

Alias for new_nitinol.

pub fn phase_fraction(&self, temp: f64, stress: f64) -> f64

Martensite volume fraction ξ for the given temperature and stress.

Uses the Liang-Rogers cosine model:

• Cooling (martensitic): ξ = 0.5 · cos(π · (T − Mf)/(Ms − Mf)) + 0.5
• Heating (austenitic): ξ = 0.5 · cos(π · (T − As)/(Af − As)) + 0.5 (then 1 − value)

The stress shifts the transformation temperatures via the Clausius-Clapeyron slope (~10 MPa/K for NiTi).

pub fn elastic_modulus(&self, xi: f64) -> f64

Effective elastic modulus at a given martensite fraction ξ.

Uses the rule of mixtures: E(ξ) = E_A + ξ · (E_M − E_A).

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

One-dimensional constitutive stress response (Pa) for a given mechanical strain and temperature.

σ = E(ξ) · ε − E(ξ) · ε_L · ξ

pub fn recovery_strain(&self, xi_start: f64, xi_end: f64) -> f64

Recoverable strain between two martensite fraction states.

Δε = h_max · (ξ_start − ξ_end)

pub fn critical_stress(&self, temp: f64) -> f64

Critical transformation stress at a given temperature.

Uses the Clausius-Clapeyron relation: σ_cr = C_M · (T − Ms) for T > Ms (stress-induced martensite). Returns 0 for T ≤ Ms.

Trait Implementations

impl Clone for ShapeMemoryAlloy

fn clone(&self) -> ShapeMemoryAlloy

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for ShapeMemoryAlloy

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

Formats the value using the given formatter.