forked from 1b-agent/fieldcraft-upstream
Christian Svensson
ea284caf80
A fluid domain may carry thermal settings: the initial temperature, gravity and the fluid's expansion coefficient for buoyancy, and a thermal condition (adiabatic, held temperature, heat flux) on each box face and on named obstacle faces, adiabatic unless told otherwise. The material then needs an isotropic conductivity and a specific heat. Boundaries are set one at a time like the flow ones. Part of #157.
707 lines
34 KiB
Rust
707 lines
34 KiB
Rust
//! Materials: linear elasticity, mass density, fluid behaviour, thermal properties (conductivity,
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//! specific heat, expansion), and the inelastic behaviours: von Mises (J2) plasticity with a
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//! bilinear, tabulated or Johnson–Cook flow stress (explicit dynamics and nonlinear static
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//! steps), Johnson–Cook damage and element erosion criteria (explicit dynamics).
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//!
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//! The records are solver-neutral and named for what they describe, never after a product's
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//! keyword or material number; the deck writers map them to each format.
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//!
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//! - Johnson–Cook flow stress: G. R. Johnson, W. H. Cook, *A constitutive model and data for
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//! metals subjected to large strains, high strain rates and high temperatures*, Proc. 7th Int.
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//! Symp. on Ballistics, The Hague, 541–547, 1983:
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//! σ_y = (A + B ε_pⁿ)(1 + C ln ε̇*)(1 − T*ᵐ), ε̇* = ε̇_p / ε̇₀, T* = (T − T_room)/(T_melt − T_room).
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//! - Johnson–Cook fracture: G. R. Johnson, W. H. Cook, *Fracture characteristics of three metals
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//! subjected to various strains, strain rates, temperatures and pressures*, Eng. Fract. Mech.
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//! 21(1):31–48, 1985: ε_f = (D1 + D2 e^{D3 σ*})(1 + D4 ln ε̇*)(1 + D5 T*), D = Σ Δε_p / ε_f.
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use serde::{Deserialize, Serialize};
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use crate::{Error, Model, Result, context, finite, insert_new, not_in_use, positive, remove_existing, replace_existing};
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/// Names of the engineering constants' shear moduli, in order.
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pub(crate) const SHEAR_MODULI: [&str; 3] = ["G12", "G13", "G23"];
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/// Linear elastic behaviour.
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#[derive(Debug, Clone, Copy, PartialEq, Serialize, Deserialize)]
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#[serde(tag = "type", rename_all = "snake_case", deny_unknown_fields)]
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pub enum Elastic {
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/// Young's modulus and Poisson's ratio.
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Isotropic { young: f64, poisson: f64 },
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/// Orthotropic, by engineering constants in the material axes 1, 2, 3 (the global X, Y, Z
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/// until material orientations land): Young's moduli `[E1, E2, E3]`, Poisson's ratios
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/// `[ν12, ν13, ν23]` (ν_ij is the contraction in j under stress in i) and shear moduli
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/// `[G12, G13, G23]`.
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EngineeringConstants { young: [f64; 3], poisson: [f64; 3], shear: [f64; 3] },
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}
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impl Elastic {
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/// Check the constants describe a stable material (positive-definite stiffness).
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pub fn validate(&self) -> Result<()> {
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match *self {
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Elastic::Isotropic { young, poisson } => {
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positive("Young's modulus", young)?;
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if !(poisson > -1.0 && poisson < 0.5) {
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return Err(Error::Invalid(format!("Poisson's ratio must be above -1 and below 0.5, got {poisson}")));
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}
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}
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Elastic::EngineeringConstants { young, poisson, shear } => {
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for (i, e) in young.iter().enumerate() {
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positive(&format!("E{}", i + 1), *e)?;
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}
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for (what, g) in SHEAR_MODULI.iter().zip(shear) {
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positive(what, g)?;
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}
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let [e1, e2, e3] = young;
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let [n12, n13, n23] = poisson;
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if poisson.iter().any(|n| !n.is_finite()) {
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return Err(Error::Invalid("Poisson's ratios must be finite numbers".into()));
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}
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// Reciprocal ratios ν_ji = ν_ij E_j / E_i; stability needs |ν_ij| < sqrt(E_i/E_j)
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// and a positive determinant of the compliance's normal block.
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let (n21, n31, n32) = (n12 * e2 / e1, n13 * e3 / e1, n23 * e3 / e2);
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for (name, nij, ei, ej) in [("ν12", n12, e1, e2), ("ν13", n13, e1, e3), ("ν23", n23, e2, e3)] {
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if !(nij.abs() < (ei / ej).sqrt()) {
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return Err(Error::Invalid(format!("{name} = {nij} is too large for the moduli (must be below {})", (ei / ej).sqrt())));
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}
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}
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let det = 1.0 - n12 * n21 - n23 * n32 - n31 * n13 - 2.0 * n21 * n32 * n13;
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if !(det > 0.0) {
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return Err(Error::Invalid("the Poisson's ratios make the material unstable (stiffness not positive definite)".into()));
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}
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}
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}
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Ok(())
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}
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}
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/// Hyperelastic behaviour of an isotropic material at large strain, in nonlinear steps.
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///
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/// The constants are the material's isotropic elastic ones: the shear modulus μ = E / (2(1 + ν))
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/// and the bulk modulus κ = E / (3(1 − 2ν)), so at small strain the material is that linear
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/// elastic one (linear steps use it so). Without this option an elastic material in a nonlinear
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/// step is St Venant–Kirchhoff (the second Piola–Kirchhoff stress linear in the Green–Lagrange
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/// strain), which is right for large rotations with small strains.
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#[derive(Debug, Clone, Copy, PartialEq, Serialize, Deserialize)]
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#[serde(tag = "type", rename_all = "snake_case", deny_unknown_fields)]
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pub enum Hyperelastic {
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/// Compressible neo-Hookean with the isochoric–volumetric split: the strain energy per
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/// reference volume W = μ/2 (Ī₁ − 3) + κ/2 (J − 1)², with Ī₁ = J^(−2/3) tr C (C₁₀ = μ/2,
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/// D₁ = 2/κ in the usual polynomial notation).
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NeoHookean {},
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/// Mooney–Rivlin (M. Mooney, J. Appl. Phys. 11:582–592, 1940; R. S. Rivlin, Phil. Trans. R.
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/// Soc. A 241:379–397, 1948), decoupled: W = C₁₀ (Ī₁ − 3) + C₀₁ (Ī₂ − 3) + κ/2 (J − 1)². The
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/// small-strain shear modulus 2 (C₁₀ + C₀₁) is the elastic μ, so `c01` sets the second
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/// invariant's share and C₁₀ = μ/2 − C₀₁ (0 ≤ C₀₁ ≤ μ/2, both constants non-negative).
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MooneyRivlin { c01: f64 },
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/// Yeoh (O. H. Yeoh, Rubber Chem. Technol. 66(5):754–771, 1993), decoupled:
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/// W = C₁₀ (Ī₁ − 3) + C₂₀ (Ī₁ − 3)² + C₃₀ (Ī₁ − 3)³ + κ/2 (J − 1)², with C₁₀ = μ/2 from the
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/// elastic constants (the small-strain shear modulus); `c20` (often negative) and `c30`
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/// shape the large-strain response.
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Yeoh { c20: f64, c30: f64 },
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}
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impl Hyperelastic {
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/// The shear and bulk moduli μ = E / (2(1 + ν)) and κ = E / (3(1 − 2ν)) the model takes from
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/// the isotropic constants.
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pub fn moduli(young: f64, poisson: f64) -> (f64, f64) {
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(young / (2.0 * (1.0 + poisson)), young / (3.0 * (1.0 - 2.0 * poisson)))
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}
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/// The name of the model, for messages.
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pub fn name(&self) -> &'static str {
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match self {
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Hyperelastic::NeoHookean {} => "neo-Hookean",
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Hyperelastic::MooneyRivlin { .. } => "Mooney–Rivlin",
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Hyperelastic::Yeoh { .. } => "Yeoh",
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}
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}
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/// The polynomial constants (C₁₀, C₀₁, C₂₀, C₃₀) for the shear modulus μ.
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pub fn constants(&self, shear: f64) -> [f64; 4] {
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match *self {
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Hyperelastic::NeoHookean {} => [shear / 2.0, 0.0, 0.0, 0.0],
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Hyperelastic::MooneyRivlin { c01 } => [shear / 2.0 - c01, c01, 0.0, 0.0],
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Hyperelastic::Yeoh { c20, c30 } => [shear / 2.0, 0.0, c20, c30],
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}
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}
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/// Check the option's constants against the elastic shear modulus μ.
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pub fn validate(&self, shear: f64) -> Result<()> {
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match *self {
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Hyperelastic::NeoHookean {} => {}
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Hyperelastic::MooneyRivlin { c01 } => {
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if !(c01 >= 0.0 && c01 <= shear / 2.0) {
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return Err(Error::Invalid(format!(
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"the Mooney–Rivlin C01 = {c01} must be within [0, μ/2 = {}] (C10 = μ/2 − C01 and C01 both non-negative)",
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shear / 2.0
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)));
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}
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}
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Hyperelastic::Yeoh { c20, c30 } => {
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finite("Yeoh C20", c20)?;
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finite("Yeoh C30", c30)?;
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}
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}
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Ok(())
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}
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}
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/// Fluid behaviour.
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#[derive(Debug, Clone, Copy, PartialEq, Serialize, Deserialize)]
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#[serde(tag = "type", rename_all = "snake_case", deny_unknown_fields)]
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pub enum Fluid {
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/// A Newtonian fluid of this dynamic viscosity μ (shear stress per shear rate; for example
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/// 1.0e-9 MPa·s for water in mm, t, s). Its kinematic viscosity is μ over the density.
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Newtonian { viscosity: f64 },
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}
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impl Fluid {
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/// The dynamic viscosity μ.
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pub fn viscosity(&self) -> f64 {
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match *self {
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Fluid::Newtonian { viscosity } => viscosity,
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}
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}
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}
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/// Most points of a plastic hardening table.
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pub const MAX_TABLE_POINTS: usize = 1000;
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/// How the yield surface moves with plastic flow.
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#[derive(Debug, Clone, Copy, Default, PartialEq, Eq, Serialize, Deserialize)]
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#[serde(rename_all = "snake_case")]
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pub enum Hardening {
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/// The yield surface grows (the yield stress rises with the equivalent plastic strain).
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#[default]
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Isotropic,
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/// The yield surface translates (linear kinematic hardening of the back stress, Prager), so
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/// reversed loading yields early (Bauschinger effect).
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Kinematic,
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}
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/// One point of a hardening table: the yield stress at an equivalent plastic strain.
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#[derive(Debug, Clone, Copy, PartialEq, Serialize, Deserialize)]
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#[serde(deny_unknown_fields)]
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pub struct HardeningPoint {
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/// Equivalent plastic strain.
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pub strain: f64,
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/// Yield stress (von Mises equivalent).
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pub stress: f64,
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}
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/// Rate-independent or Johnson–Cook von Mises plasticity (needs isotropic elasticity).
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#[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
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#[serde(tag = "type", rename_all = "snake_case", deny_unknown_fields)]
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pub enum Plastic {
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/// Linear hardening: the yield stress `yield_stress + hardening_modulus · ε_p` (isotropic), or
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/// a yield surface of radius `yield_stress` whose centre moves with modulus
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/// `hardening_modulus` (kinematic). The hardening modulus is the slope of the uniaxial stress
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/// against the plastic strain (0: perfectly plastic).
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Bilinear {
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yield_stress: f64,
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#[serde(default)]
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hardening_modulus: f64,
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#[serde(default)]
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hardening: Hardening,
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},
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/// Isotropic hardening by a table of yield stress against equivalent plastic strain, linear
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/// between the points and constant after the last. The first point is at plastic strain 0;
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/// the strains increase.
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Table { points: Vec<HardeningPoint> },
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/// Johnson–Cook flow stress (isotropic hardening): `a`, `b`, `n` the strain hardening, `c`
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/// the strain-rate sensitivity relative to `reference_strain_rate` (rates below it count as
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/// it), `m` the thermal softening between `room_temperature` and `melt_temperature`. With a
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/// `specific_heat`, plastic work heats the material adiabatically (the fraction
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/// `taylor_quinney` of it); without one the temperature stays at room temperature.
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JohnsonCook {
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a: f64,
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b: f64,
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n: f64,
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#[serde(default)]
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c: f64,
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#[serde(default = "one")]
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m: f64,
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#[serde(default = "one")]
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reference_strain_rate: f64,
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room_temperature: f64,
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melt_temperature: f64,
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#[serde(default, skip_serializing_if = "Option::is_none")]
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specific_heat: Option<f64>,
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#[serde(default = "default_taylor_quinney")]
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taylor_quinney: f64,
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},
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}
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fn one() -> f64 {
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1.0
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}
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fn default_taylor_quinney() -> f64 {
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0.9
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}
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impl Plastic {
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/// The name of the kind, for messages.
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pub fn name(&self) -> &'static str {
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match self {
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Plastic::Bilinear { .. } => "bilinear plasticity",
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Plastic::Table { .. } => "tabulated plasticity",
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Plastic::JohnsonCook { .. } => "Johnson–Cook plasticity",
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}
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}
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/// The initial yield stress (at zero plastic strain, the reference rate and room
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/// temperature).
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pub fn initial_yield(&self) -> f64 {
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match self {
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Plastic::Bilinear { yield_stress, .. } => *yield_stress,
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Plastic::Table { points } => points.first().map_or(0.0, |p| p.stress),
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Plastic::JohnsonCook { a, .. } => *a,
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}
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}
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pub fn validate(&self) -> Result<()> {
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let nonnegative = |what: &str, v: f64| {
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if v >= 0.0 && v.is_finite() { Ok(v) } else { Err(Error::Invalid(format!("{what} must be a finite number ≥ 0, got {v}"))) }
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};
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match self {
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Plastic::Bilinear { yield_stress, hardening_modulus, .. } => {
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positive("yield stress", *yield_stress)?;
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nonnegative("hardening modulus", *hardening_modulus)?;
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}
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Plastic::Table { points } => {
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if points.is_empty() || points.len() > MAX_TABLE_POINTS {
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return Err(Error::Invalid(format!("a hardening table has 1 to {MAX_TABLE_POINTS} points, got {}", points.len())));
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}
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if points.first().is_some_and(|p| p.strain != 0.0) {
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return Err(Error::Invalid("a hardening table starts at plastic strain 0".into()));
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}
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for p in points {
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nonnegative("plastic strain", p.strain)?;
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positive("yield stress", p.stress)?;
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}
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if points.windows(2).any(|w| w.get(1).map(|b| b.strain) <= w.first().map(|a| a.strain)) {
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return Err(Error::Invalid("the plastic strains of a hardening table must increase".into()));
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}
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}
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Plastic::JohnsonCook { a, b, n, c, m, reference_strain_rate, room_temperature, melt_temperature, specific_heat, taylor_quinney } => {
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positive("A", *a)?;
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nonnegative("B", *b)?;
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nonnegative("n", *n)?;
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nonnegative("C", *c)?;
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positive("m", *m)?;
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positive("reference strain rate", *reference_strain_rate)?;
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finite("room temperature", *room_temperature)?;
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finite("melt temperature", *melt_temperature)?;
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if !(melt_temperature > room_temperature) {
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return Err(Error::Invalid(format!(
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"the melt temperature {melt_temperature} must be above the room temperature {room_temperature}"
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)));
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}
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if let Some(cp) = specific_heat {
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positive("specific heat", *cp)?;
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}
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if !(0.0..=1.0).contains(taylor_quinney) {
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return Err(Error::Invalid(format!("the Taylor–Quinney fraction is in [0, 1], got {taylor_quinney}")));
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}
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}
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}
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Ok(())
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}
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}
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/// A property given per material axis: one value for every direction, or three along the
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/// material axes 1, 2, 3 (the global X, Y, Z until material orientations land).
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#[derive(Debug, Clone, Copy, PartialEq, Serialize, Deserialize)]
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#[serde(untagged)]
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pub enum Directional {
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Isotropic(f64),
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Orthotropic([f64; 3]),
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}
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impl Directional {
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/// The values along the three axes.
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pub fn axes(self) -> [f64; 3] {
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match self {
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Directional::Isotropic(v) => [v; 3],
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Directional::Orthotropic(v) => v,
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}
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}
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}
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/// Heat conduction and thermal expansion.
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#[derive(Debug, Clone, Copy, Default, PartialEq, Serialize, Deserialize)]
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#[serde(deny_unknown_fields)]
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pub struct Thermal {
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/// Conductivity k (power per length per temperature): q = −k ∇T.
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#[serde(default, skip_serializing_if = "Option::is_none")]
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pub conductivity: Option<Directional>,
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/// Specific heat c (energy per mass per temperature); with the density, the heat capacity
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/// of transient heat transfer.
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#[serde(default, skip_serializing_if = "Option::is_none")]
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pub specific_heat: Option<f64>,
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/// Linear expansion coefficient α (strain per temperature): ε_th = α (T − T_ref).
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#[serde(default, skip_serializing_if = "Option::is_none")]
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pub expansion: Option<Directional>,
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/// The temperature at which thermal strain is zero.
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#[serde(default)]
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pub reference_temperature: f64,
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}
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impl Thermal {
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pub fn validate(&self) -> Result<()> {
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if let Some(k) = self.conductivity {
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for v in k.axes() {
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positive("conductivity", v)?;
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}
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}
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if let Some(c) = self.specific_heat {
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positive("specific heat", c)?;
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}
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if let Some(a) = self.expansion {
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for v in a.axes() {
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finite("expansion coefficient", v)?;
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}
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}
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finite("reference temperature", self.reference_temperature)?;
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if self.conductivity.is_none() && self.specific_heat.is_none() && self.expansion.is_none() {
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return Err(Error::Invalid("thermal properties need a conductivity, a specific heat or an expansion coefficient".into()));
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}
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Ok(())
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}
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}
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/// Damage that accumulates with plastic strain; a material point fails when it reaches 1.
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#[derive(Debug, Clone, Copy, PartialEq, Serialize, Deserialize)]
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#[serde(tag = "type", rename_all = "snake_case", deny_unknown_fields)]
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pub enum Damage {
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/// Johnson–Cook fracture strain ε_f = (d1 + d2 e^{d3 σ*})(1 + d4 ln ε̇*)(1 + d5 T*), with σ*
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/// the mean stress over the von Mises stress; ε̇* and T* as in Johnson–Cook plasticity (`d4`
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/// and `d5` need it).
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JohnsonCook {
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d1: f64,
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d2: f64,
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d3: f64,
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#[serde(default)]
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d4: f64,
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#[serde(default)]
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d5: f64,
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},
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}
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/// When elements of the material are removed from the analysis (eroded), besides failing by
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/// [`Damage`].
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#[derive(Debug, Clone, Copy, PartialEq, Serialize, Deserialize)]
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#[serde(deny_unknown_fields)]
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pub struct Erosion {
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/// The equivalent plastic strain at which an element erodes.
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pub plastic_strain: f64,
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}
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/// A material.
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#[derive(Debug, Clone, Default, PartialEq, Serialize, Deserialize)]
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#[serde(deny_unknown_fields)]
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pub struct Material {
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#[serde(default, skip_serializing_if = "Option::is_none")]
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pub elastic: Option<Elastic>,
|
||
/// Large-strain behaviour in nonlinear steps, built on the isotropic elastic constants.
|
||
#[serde(default, skip_serializing_if = "Option::is_none")]
|
||
pub hyperelastic: Option<Hyperelastic>,
|
||
/// Mass per volume, needed by frequency steps, gravity and transient heat transfer.
|
||
#[serde(default, skip_serializing_if = "Option::is_none")]
|
||
pub density: Option<f64>,
|
||
/// How it flows, for fluid domains (needs a density).
|
||
#[serde(default, skip_serializing_if = "Option::is_none")]
|
||
pub fluid: Option<Fluid>,
|
||
/// Von Mises plasticity (explicit dynamics and nonlinear static steps; the linear solvers use
|
||
/// the elastic constants alone).
|
||
#[serde(default, skip_serializing_if = "Option::is_none")]
|
||
pub plastic: Option<Plastic>,
|
||
/// Damage to failure (explicit dynamics: a failed element erodes).
|
||
#[serde(default, skip_serializing_if = "Option::is_none")]
|
||
pub damage: Option<Damage>,
|
||
/// Erosion criteria (explicit dynamics).
|
||
#[serde(default, skip_serializing_if = "Option::is_none")]
|
||
pub erosion: Option<Erosion>,
|
||
#[serde(default, skip_serializing_if = "Option::is_none")]
|
||
pub thermal: Option<Thermal>,
|
||
}
|
||
|
||
impl Material {
|
||
pub fn validate(&self) -> Result<()> {
|
||
if self.elastic.is_none() && self.density.is_none() && self.fluid.is_none() && self.thermal.is_none() {
|
||
return Err(Error::Invalid("a material needs elastic constants, a density, fluid behaviour or thermal properties".into()));
|
||
}
|
||
if let Some(f) = &self.fluid {
|
||
positive("viscosity", f.viscosity())?;
|
||
if self.density.is_none() {
|
||
return Err(Error::Invalid("a fluid needs a density".into()));
|
||
}
|
||
}
|
||
if let Some(e) = &self.elastic {
|
||
e.validate()?;
|
||
}
|
||
if let Some(h) = &self.hyperelastic {
|
||
if !matches!(self.elastic, Some(Elastic::Isotropic { .. })) {
|
||
return Err(Error::Invalid(format!("{} hyperelasticity needs isotropic elastic constants", h.name())));
|
||
}
|
||
if self.plastic.is_some() {
|
||
return Err(Error::Invalid(format!("plasticity of a {} hyperelastic material is not supported yet", h.name())));
|
||
}
|
||
if let Some(Elastic::Isotropic { young, poisson }) = self.elastic {
|
||
h.validate(Hyperelastic::moduli(young, poisson).0)?;
|
||
}
|
||
}
|
||
if let Some(d) = self.density {
|
||
positive("density", d)?;
|
||
}
|
||
if let Some(p) = &self.plastic {
|
||
if !matches!(self.elastic, Some(Elastic::Isotropic { .. })) {
|
||
return Err(Error::Invalid(format!("{} needs isotropic elastic constants", p.name())));
|
||
}
|
||
p.validate()?;
|
||
}
|
||
if let Some(Damage::JohnsonCook { d1, d2, d3, d4, d5 }) = self.damage {
|
||
for (what, v) in [("D1", d1), ("D2", d2), ("D3", d3), ("D4", d4), ("D5", d5)] {
|
||
finite(what, v)?;
|
||
}
|
||
match &self.plastic {
|
||
None => return Err(Error::Invalid("damage needs plasticity (it accumulates with the plastic strain)".into())),
|
||
Some(Plastic::JohnsonCook { .. }) => {}
|
||
Some(_) if d4 != 0.0 || d5 != 0.0 => {
|
||
return Err(Error::Invalid(
|
||
"the damage terms D4 and D5 need Johnson–Cook plasticity (its reference strain rate and temperatures)".into(),
|
||
));
|
||
}
|
||
Some(_) => {}
|
||
}
|
||
}
|
||
if let Some(e) = self.erosion {
|
||
positive("erosion plastic strain", e.plastic_strain)?;
|
||
if self.plastic.is_none() {
|
||
return Err(Error::Invalid("a plastic-strain erosion criterion needs plasticity".into()));
|
||
}
|
||
}
|
||
if let Some(t) = &self.thermal {
|
||
t.validate()?;
|
||
}
|
||
Ok(())
|
||
}
|
||
}
|
||
|
||
impl Model {
|
||
pub fn materials(&self) -> &std::collections::BTreeMap<String, Material> {
|
||
&self.materials
|
||
}
|
||
|
||
pub fn material(&self, name: &str) -> Option<&Material> {
|
||
self.materials.get(name)
|
||
}
|
||
|
||
/// The hyperelastic materials some section uses, by name.
|
||
pub fn hyperelastic_in_use(&self) -> std::collections::BTreeSet<&str> {
|
||
self.sections.values().map(|s| s.material.as_str()).filter(|m| self.material(m).is_some_and(|m| m.hyperelastic.is_some())).collect()
|
||
}
|
||
|
||
pub fn add_material(&mut self, name: &str, material: Material) -> Result<()> {
|
||
material.validate().map_err(|e| context("material", name, e))?;
|
||
insert_new(&mut self.materials, "material", name, material)
|
||
}
|
||
|
||
pub fn replace_material(&mut self, name: &str, material: Material) -> Result<()> {
|
||
material.validate().map_err(|e| context("material", name, e))?;
|
||
self.check_material_fits_fluid_domains(name, &material)?;
|
||
replace_existing(&mut self.materials, "material", name, material)
|
||
}
|
||
|
||
/// The definitions that refer to a material, as `kind \`name\`` strings.
|
||
pub fn material_users(&self, name: &str) -> Vec<String> {
|
||
let mut users: Vec<String> = self.sections.iter().filter(|(_, s)| s.material == name).map(|(n, _)| format!("section `{n}`")).collect();
|
||
users.extend(self.fluid_domains_of_material(name).map(|n| format!("fluid domain `{n}`")));
|
||
users
|
||
}
|
||
|
||
pub fn remove_material(&mut self, name: &str) -> Result<()> {
|
||
not_in_use("material", name, self.material_users(name))?;
|
||
remove_existing(&mut self.materials, "material", name).map(|_| ())
|
||
}
|
||
}
|
||
|
||
#[cfg(test)]
|
||
mod tests {
|
||
use super::*;
|
||
|
||
fn iso(young: f64, poisson: f64) -> Material {
|
||
Material { elastic: Some(Elastic::Isotropic { young, poisson }), ..Material::default() }
|
||
}
|
||
|
||
#[test]
|
||
fn materials_validate_and_name_the_bad_constant() {
|
||
let mut m = Model::default();
|
||
m.add_material("Steel", Material { density: Some(7.85e-9), ..iso(2.1e5, 0.3) }).unwrap();
|
||
assert!(m.add_material("Steel", iso(1.0, 0.3)).is_err(), "duplicate");
|
||
for bad in [iso(0.0, 0.3), iso(-1.0, 0.3), iso(f64::NAN, 0.3), iso(1.0, 0.5), iso(1.0, -1.0), iso(1.0, f64::INFINITY), Material::default()] {
|
||
let e = m.add_material("Bad", bad).unwrap_err();
|
||
assert!(e.to_string().contains("material `Bad`"), "{e}");
|
||
}
|
||
assert!(m.add_material("Light", Material { density: Some(-1.0), ..Material::default() }).is_err());
|
||
let fluid = |viscosity, density| Material { density, fluid: Some(Fluid::Newtonian { viscosity }), ..Material::default() };
|
||
m.add_material("Water", fluid(1.0e-9, Some(1.0e-9))).unwrap();
|
||
for bad in [fluid(0.0, Some(1.0)), fluid(-1.0, Some(1.0)), fluid(f64::NAN, Some(1.0)), fluid(1.0, None)] {
|
||
assert!(m.add_material("Bad", bad).is_err());
|
||
}
|
||
assert!(m.add_material("1st", iso(1.0, 0.3)).is_err(), "names start with a letter");
|
||
assert!(m.add_material("has space", iso(1.0, 0.3)).is_err());
|
||
m.replace_material("Steel", iso(2.0e5, 0.29)).unwrap();
|
||
assert!(m.replace_material("Nope", iso(2.0e5, 0.29)).is_err());
|
||
assert_eq!(m.materials().len(), 2);
|
||
}
|
||
|
||
#[test]
|
||
fn orthotropic_stability() {
|
||
let ortho = |poisson| Elastic::EngineeringConstants { young: [140e3, 10e3, 10e3], poisson, shear: [5e3, 5e3, 3.8e3] };
|
||
ortho([0.3, 0.3, 0.4]).validate().unwrap();
|
||
// ν21 = ν12 E2/E1 is small; ν12 itself may exceed 0.5 in a stiff direction.
|
||
ortho([0.9, 0.3, 0.4]).validate().unwrap();
|
||
assert!(ortho([4.0, 0.3, 0.4]).validate().is_err(), "|ν12| < sqrt(E1/E2) = 3.74");
|
||
assert!(ortho([0.3, 0.3, 1.0]).validate().is_err());
|
||
assert!(ortho([3.5, 3.5, 0.9]).validate().is_err(), "determinant");
|
||
assert!(ortho([0.3, f64::NAN, 0.4]).validate().is_err());
|
||
let zero_shear = Elastic::EngineeringConstants { young: [1.0; 3], poisson: [0.0; 3], shear: [1.0, 0.0, 1.0] };
|
||
assert!(zero_shear.validate().unwrap_err().to_string().contains("G13"));
|
||
}
|
||
|
||
fn steel() -> Material {
|
||
Material { density: Some(7.85e-9), ..iso(2.1e5, 0.3) }
|
||
}
|
||
|
||
fn jc() -> Plastic {
|
||
Plastic::JohnsonCook {
|
||
a: 792.0,
|
||
b: 510.0,
|
||
n: 0.26,
|
||
c: 0.014,
|
||
m: 1.03,
|
||
reference_strain_rate: 1.0,
|
||
room_temperature: 294.0,
|
||
melt_temperature: 1793.0,
|
||
specific_heat: Some(4.77e8),
|
||
taylor_quinney: 0.9,
|
||
}
|
||
}
|
||
|
||
#[test]
|
||
fn plasticity_damage_and_erosion_validate() {
|
||
let ok = |p: Plastic| Material { plastic: Some(p), ..steel() }.validate();
|
||
ok(Plastic::Bilinear { yield_stress: 250.0, hardening_modulus: 1000.0, hardening: Hardening::Kinematic }).unwrap();
|
||
ok(Plastic::Table { points: vec![HardeningPoint { strain: 0.0, stress: 250.0 }, HardeningPoint { strain: 0.1, stress: 300.0 }] }).unwrap();
|
||
ok(jc()).unwrap();
|
||
for bad in [
|
||
Plastic::Bilinear { yield_stress: 0.0, hardening_modulus: 0.0, hardening: Hardening::Isotropic },
|
||
Plastic::Bilinear { yield_stress: 1.0, hardening_modulus: -1.0, hardening: Hardening::Isotropic },
|
||
Plastic::Table { points: vec![] },
|
||
Plastic::Table { points: vec![HardeningPoint { strain: 0.1, stress: 250.0 }] },
|
||
Plastic::Table { points: vec![HardeningPoint { strain: 0.0, stress: 250.0 }, HardeningPoint { strain: 0.0, stress: 300.0 }] },
|
||
Plastic::Table { points: vec![HardeningPoint { strain: 0.0, stress: f64::NAN }] },
|
||
Plastic::Table { points: vec![HardeningPoint { strain: 0.0, stress: 1.0 }; MAX_TABLE_POINTS + 1] },
|
||
] {
|
||
assert!(ok(bad.clone()).is_err(), "{bad:?}");
|
||
}
|
||
let mut cold = jc();
|
||
if let Plastic::JohnsonCook { melt_temperature, room_temperature, .. } = &mut cold {
|
||
*melt_temperature = *room_temperature;
|
||
}
|
||
assert!(ok(cold).is_err(), "melt above room");
|
||
// Plasticity needs isotropic elasticity; damage and erosion need plasticity.
|
||
let ortho = Elastic::EngineeringConstants { young: [1.0; 3], poisson: [0.0; 3], shear: [1.0; 3] };
|
||
assert!(Material { elastic: Some(ortho), plastic: Some(jc()), ..steel() }.validate().is_err());
|
||
let damage = Damage::JohnsonCook { d1: 0.05, d2: 3.44, d3: -2.12, d4: 0.002, d5: 0.61 };
|
||
Material { plastic: Some(jc()), damage: Some(damage), erosion: Some(Erosion { plastic_strain: 2.0 }), ..steel() }.validate().unwrap();
|
||
assert!(Material { damage: Some(damage), ..steel() }.validate().is_err());
|
||
let bilinear = Plastic::Bilinear { yield_stress: 250.0, hardening_modulus: 0.0, hardening: Hardening::Isotropic };
|
||
assert!(Material { plastic: Some(bilinear.clone()), damage: Some(damage), ..steel() }.validate().is_err(), "D4, D5 need Johnson–Cook");
|
||
let plain = Damage::JohnsonCook { d1: 0.5, d2: 0.0, d3: 0.0, d4: 0.0, d5: 0.0 };
|
||
Material { plastic: Some(bilinear), damage: Some(plain), ..steel() }.validate().unwrap();
|
||
assert!(Material { erosion: Some(Erosion { plastic_strain: 1.0 }), ..steel() }.validate().is_err());
|
||
// JSON: defaults fill in, unknown fields are refused.
|
||
let m: Material = serde_json::from_str(
|
||
r#"{"elastic":{"type":"isotropic","young":1,"poisson":0.3},"plastic":{"type":"johnson_cook","a":1,"b":2,"n":0.5,"room_temperature":0,"melt_temperature":100}}"#,
|
||
)
|
||
.unwrap();
|
||
assert!(
|
||
matches!(m.plastic, Some(Plastic::JohnsonCook { m, reference_strain_rate, taylor_quinney, .. }) if m == 1.0 && reference_strain_rate == 1.0 && taylor_quinney == 0.9)
|
||
);
|
||
assert!(serde_json::from_str::<Material>(r#"{"density":1,"plastic":{"type":"bilinear","yield_stress":1,"oops":2}}"#).is_err());
|
||
let text = serde_json::to_string(&Material { plastic: Some(jc()), damage: Some(damage), ..steel() }).unwrap();
|
||
assert_eq!(serde_json::from_str::<Material>(&text).unwrap(), Material { plastic: Some(jc()), damage: Some(damage), ..steel() });
|
||
}
|
||
|
||
#[test]
|
||
fn hyperelasticity_builds_on_isotropic_constants() {
|
||
let m: Material = serde_json::from_value(serde_json::json!({
|
||
"elastic": {"type": "isotropic", "young": 3.0, "poisson": 0.49}, "hyperelastic": {"type": "neo_hookean"}
|
||
}))
|
||
.unwrap();
|
||
m.validate().unwrap();
|
||
assert_eq!(m.hyperelastic, Some(Hyperelastic::NeoHookean {}));
|
||
let back: Material = serde_json::from_value(serde_json::to_value(&m).unwrap()).unwrap();
|
||
assert_eq!(back, m);
|
||
assert!(serde_json::from_value::<Material>(serde_json::json!({"hyperelastic": {"type": "neo_hookean", "c10": 1}})).is_err());
|
||
let alone = Material { hyperelastic: Some(Hyperelastic::NeoHookean {}), density: Some(1.0), ..Material::default() };
|
||
assert!(alone.validate().is_err(), "needs isotropic constants");
|
||
let ortho = Elastic::EngineeringConstants { young: [1.0; 3], poisson: [0.0; 3], shear: [1.0; 3] };
|
||
assert!(Material { elastic: Some(ortho), ..alone }.validate().is_err());
|
||
let plastic = Plastic::Bilinear { yield_stress: 1.0, hardening_modulus: 0.0, hardening: Hardening::Isotropic };
|
||
assert!(Material { plastic: Some(plastic), ..m.clone() }.validate().is_err());
|
||
// Mooney–Rivlin and Yeoh: μ = E/(2(1 + ν)) = 1.00671 here, so C01 is within [0, μ/2].
|
||
let mr: Material = serde_json::from_value(serde_json::json!({
|
||
"elastic": {"type": "isotropic", "young": 3.0, "poisson": 0.49}, "hyperelastic": {"type": "mooney_rivlin", "c01": 0.1}
|
||
}))
|
||
.unwrap();
|
||
mr.validate().unwrap();
|
||
let mu = Hyperelastic::moduli(3.0, 0.49).0;
|
||
let c = Hyperelastic::MooneyRivlin { c01: 0.1 }.constants(mu);
|
||
assert!((2.0 * (c[0] + c[1]) - mu).abs() < 1e-15 && c[1] == 0.1);
|
||
let yeoh = Hyperelastic::Yeoh { c20: -0.01, c30: 0.001 };
|
||
assert_eq!(yeoh.constants(mu), [mu / 2.0, 0.0, -0.01, 0.001]);
|
||
assert!(Material { hyperelastic: Some(yeoh), ..m.clone() }.validate().is_ok());
|
||
for bad in [
|
||
Hyperelastic::MooneyRivlin { c01: -0.1 },
|
||
Hyperelastic::MooneyRivlin { c01: 0.6 },
|
||
Hyperelastic::MooneyRivlin { c01: f64::NAN },
|
||
Hyperelastic::Yeoh { c20: f64::INFINITY, c30: 0.0 },
|
||
Hyperelastic::Yeoh { c20: 0.0, c30: f64::NAN },
|
||
] {
|
||
assert!(Material { hyperelastic: Some(bad), ..m.clone() }.validate().is_err(), "{bad:?}");
|
||
}
|
||
}
|
||
|
||
#[test]
|
||
fn thermal_properties() {
|
||
let m: Material = serde_json::from_value(serde_json::json!({
|
||
"thermal": {"conductivity": [1, 2, 3], "specific_heat": 460, "expansion": 1.2e-5, "reference_temperature": 20}
|
||
}))
|
||
.unwrap();
|
||
let t = m.thermal.unwrap();
|
||
assert_eq!(t.conductivity.unwrap().axes(), [1.0, 2.0, 3.0]);
|
||
assert_eq!(t.expansion.unwrap().axes(), [1.2e-5; 3]);
|
||
assert!(m.validate().is_ok(), "a heat-only material needs no elasticity");
|
||
let back: Material = serde_json::from_value(serde_json::to_value(&m).unwrap()).unwrap();
|
||
assert_eq!(back, m);
|
||
for bad in [
|
||
Thermal::default(),
|
||
Thermal { conductivity: Some(Directional::Isotropic(0.0)), ..Thermal::default() },
|
||
Thermal { conductivity: Some(Directional::Orthotropic([1.0, -1.0, 1.0])), ..Thermal::default() },
|
||
Thermal { specific_heat: Some(f64::NAN), ..Thermal::default() },
|
||
Thermal { expansion: Some(Directional::Isotropic(f64::INFINITY)), ..Thermal::default() },
|
||
Thermal { expansion: Some(Directional::Isotropic(1e-5)), reference_temperature: f64::NAN, ..Thermal::default() },
|
||
] {
|
||
assert!(bad.validate().is_err(), "{bad:?}");
|
||
}
|
||
assert!(serde_json::from_value::<Material>(serde_json::json!({"thermal": {"conductivity": [1, 2]}})).is_err());
|
||
assert!(serde_json::from_value::<Material>(serde_json::json!({"thermal": {"heat": 1}})).is_err());
|
||
// Negative expansion (invar-like behaviour of some composites) is allowed.
|
||
assert!(Thermal { expansion: Some(Directional::Isotropic(-1e-6)), ..Thermal::default() }.validate().is_ok());
|
||
}
|
||
}
|