Struct LogNormalRetardation 

pub struct LogNormalRetardation {
    pub j0: f64,
    pub j_lm: f64,
    pub tau_c: f64,
    pub sigma: f64,
}

Continuous retardation spectrum L(τ) modelled as a log-normal distribution.

Creep compliance: J(t) = J₀ + ∫ L(τ)/τ · (1 - exp(-t/τ)) d ln τ

For the log-normal spectrum:

L(τ) = J_lm / (σ √(2π)) · exp(-(ln(τ/τ_c))² / (2σ²))

The integral is evaluated numerically over a wide range of τ.

Fields

j0: f64

Instantaneous compliance J₀ (1/Pa).

j_lm: f64

Total creep compliance amplitude J_lm (1/Pa).

tau_c: f64

Central retardation time τ_c (s).

sigma: f64

Log-width σ (dimensionless, > 0).

Implementations

impl LogNormalRetardation

pub fn new(j0: f64, j_lm: f64, tau_c: f64, sigma: f64) -> Self

Create a new log-normal retardation model.

pub fn spectrum(&self, tau: f64) -> f64

L(τ): log-normal retardation spectrum evaluated at τ.

pub fn creep_compliance(&self, t: f64) -> f64

Creep compliance J(t) evaluated by Gauss-Legendre quadrature (20 pts) over ln τ ∈ [ln τ_c - 5σ, ln τ_c + 5σ].

pub fn storage_compliance(&self, omega: f64) -> f64

Storage compliance J’(ω) = J₀ + ∫ L(τ)/(1 + (ωτ)²) d ln τ.

pub fn loss_compliance(&self, omega: f64) -> f64

Loss compliance J’’(ω) = ∫ L(τ) ωτ/(1 + (ωτ)²) d ln τ.

Trait Implementations

impl Clone for LogNormalRetardation

fn clone(&self) -> LogNormalRetardation

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for LogNormalRetardation

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

Formats the value using the given formatter.