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Explicit X2: large deformation, J2 and Johnson-Cook plasticity, damage and erosion (M10)

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- model: materials gain solver-neutral plastic (bilinear isotropic/kinematic,
  hardening table, Johnson-Cook with adiabatic heating), damage (Johnson-Cook
  D1-D5) and erosion (plastic strain); explicit steps gain nonlinear_geometry
  (default on) and stress_rate (jaumann | green_naghdi).
- fem: rotation (Hughes-Winget, Flanagan-Taylor), plasticity (radial return,
  capped bracketed Newton for Johnson-Cook, damage; the update takes the
  mechanical strain increment so thermal strains can be subtracted), closed-form
  hex8 gradients for deformed configurations.
- explicit: updated Lagrangian hex8/tet4, per-element material state, erosion
  with reported energy, plastic work in the energy account.
- solver: warns that the linear solver uses the elastic constants of plastic
  materials (results hash-identical).
- decks: Abaqus *PLASTIC (+ Johnson-Cook keywords), Nastran MATS1/TABLES1,
  LS-DYNA *MAT_PLASTIC_KINEMATIC / *MAT_PIECEWISE_LINEAR_PLASTICITY; what a
  format cannot express is reported as Unsupported.
- engine: model.material.plasticity, model.material.damage (catalogue ready),
  explicit element probe, eroded elements in the solve summary.

Step commits before the rebase onto the DOF framework: branch explicit-x2-steps.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01NmAttHhUZTokgPeEJia8sm
This commit is contained in:
jyvikoandClaude Opus 5.5 authored and Irakli Kourtis committed 2026-10-13 20:52:57 -04:00
1 parent 4c0fcc80ad
commit 50764def18
38 files changed
+2839 -254
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crates/decks/src/lsdyna/mod.rs
+78 -7
View File
@@ -8,7 +8,13 @@
//! `*SECTION_BEAM` (rods as trusses) and the element formulation mapped from the section's
//! ([`elements`]); `*HOURGLASS` where a reduced-integration formulation needs it;
//! - `*MAT_ELASTIC` for isotropic and `*MAT_ORTHOTROPIC_ELASTIC` (global material axes) for
//! orthotropic materials;
//! orthotropic materials; von Mises plasticity as `*MAT_PLASTIC_KINEMATIC` (bilinear: the
//! tangent modulus E·H/(E + H) of the uniaxial curve, β = 1 isotropic or 0 kinematic, the
//! erosion plastic strain as its failure strain) or `*MAT_PIECEWISE_LINEAR_PLASTICITY` (a
//! hardening table as a `*DEFINE_CURVE` of yield stress against plastic strain, the erosion
//! plastic strain as its failure strain). Johnson–Cook plasticity and damage are reported: their
//! LS-DYNA material needs an equation of state and belongs to explicit analyses, which this
//! writer does not write yet;
//! - `*ELEMENT_SOLID` (tetrahedra and wedges as degenerate hexahedra, 10-node tetrahedra),
//! `*ELEMENT_SOLID_H20`, `*ELEMENT_SHELL` and `*ELEMENT_BEAM`;
//! - `*SET_NODE_LIST` and `*SET_SEGMENT` for the sets boundary conditions, loads and couplings
@@ -47,8 +53,8 @@ mod elements;
use std::collections::{BTreeMap, BTreeSet};
use modelcraft_model::{
BoundaryCondition, CouplingKind, Diagnostic, Dofs, Elastic, Element, ElementKind, Load, Model, OutputVariable, Procedure, Resolved, Section,
SectionKind, Step, Target,
BoundaryCondition, CouplingKind, Diagnostic, Dofs, Elastic, Element, ElementKind, Hardening, Load, Material, Model, OutputVariable, Plastic,
Procedure, Resolved, Section, SectionKind, Step, Target,
};
use crate::{Error, Result};
@@ -117,6 +123,8 @@ struct Plan<'a> {
uniform: BTreeMap<&'a str, ([f64; 3], u32)>,
/// The part set gravity acts on, when it acts on a set.
gravity_parts: Option<Vec<u32>>,
/// Material name → the curve id of its hardening table.
curves: BTreeMap<&'a str, u32>,
}
/// Write the model as an LS-DYNA keyword deck.
@@ -304,13 +312,25 @@ fn plan<'a>(model: &'a Model, r: &Resolved) -> Result<Plan<'a>> {
None
}
};
for m in materials.keys() {
if model.material(m).is_some_and(|m| m.density.is_none()) {
refused.insert(format!("material `{m}` has no density, and LS-DYNA requires a mass density on every material"));
let mut curves = BTreeMap::new();
for name in materials.keys() {
let Some(m) = model.material(name) else { continue };
if m.density.is_none() {
refused.insert(format!("material `{name}` has no density, and LS-DYNA requires a mass density on every material"));
}
if matches!(m.plastic, Some(Plastic::JohnsonCook { .. })) || m.damage.is_some() {
refused.insert(format!(
"material `{name}`: Johnson–Cook plasticity and damage (LS-DYNA's Johnson–Cook material needs an equation of state and is for explicit analyses, which this writer does not write yet)"
));
}
if matches!(m.plastic, Some(Plastic::Table { .. })) {
// Curve ids after the steps' load ramps (ids 1 to the number of steps).
let lcid = u32::try_from(model.steps().len() + 1 + curves.len()).map_err(|_| Error::Limit("too many curves".into()))?;
curves.insert(*name, lcid);
}
}
crate::unsupported(FORMAT, refused)?;
Ok(Plan { parts, materials, hourglasses, sets, node_sets, segment_sets, uniform, gravity_parts })
Ok(Plan { parts, materials, hourglasses, sets, node_sets, segment_sets, uniform, gravity_parts, curves })
}
/// A 1-based id from a 0-based index.
@@ -374,6 +394,7 @@ fn materials(d: &mut Deck, model: &Model, plan: &Plan) -> Result<()> {
let m = model.material(name).ok_or_else(|| broken(format!("material `{name}`")))?;
let rho = m.density.unwrap_or_default();
match m.elastic {
Some(Elastic::Isotropic { young, poisson }) if m.plastic.is_some() => plastic_material(d, name, mid, rho, young, poisson, m, plan)?,
Some(Elastic::Isotropic { young, poisson }) => {
d.line("*MAT_ELASTIC_TITLE");
d.line(name);
@@ -401,6 +422,56 @@ fn materials(d: &mut Deck, model: &Model, plan: &Plan) -> Result<()> {
Ok(())
}
/// The plastic materials: `*MAT_PLASTIC_KINEMATIC` or `*MAT_PIECEWISE_LINEAR_PLASTICITY` with its
/// curve, in place of `*MAT_ELASTIC`.
fn plastic_material(d: &mut Deck, name: &str, mid: u32, rho: f64, young: f64, poisson: f64, m: &Material, plan: &Plan) -> Result<()> {
let fail = m.erosion.map_or(Field::Blank, |e| Field::from(e.plastic_strain));
match &m.plastic {
Some(Plastic::Bilinear { yield_stress, hardening_modulus, hardening }) => {
d.line("*MAT_PLASTIC_KINEMATIC_TITLE");
d.line(name);
d.header(&["mid", "ro", "e", "pr", "sigy", "etan", "beta"]);
let tangent = young * hardening_modulus / (young + hardening_modulus);
let beta = if *hardening == Hardening::Kinematic { 0.0 } else { 1.0 };
d.card([
Field::from(mid),
Field::from(rho),
Field::from(young),
Field::from(poisson),
Field::from(*yield_stress),
Field::from(tangent),
Field::from(beta),
]);
d.header(&["src", "srp", "fs"]);
d.card([Field::Blank, Field::Blank, fail]);
}
Some(Plastic::Table { points }) => {
let lcid = plan.curves.get(name).copied().ok_or_else(|| broken(format!("material `{name}` has no curve")))?;
d.line("*MAT_PIECEWISE_LINEAR_PLASTICITY_TITLE");
d.line(name);
d.header(&["mid", "ro", "e", "pr", "sigy", "etan", "fail"]);
let first = m.plastic.as_ref().map_or(0.0, Plastic::initial_yield);
d.card([Field::from(mid), Field::from(rho), Field::from(young), Field::from(poisson), Field::from(first), Field::Blank, fail]);
d.header(&["c", "p", "lcss"]);
d.card([Field::Blank, Field::Blank, Field::from(lcid)]);
d.header(&["eps1"]);
d.card([Field::Blank]);
d.header(&["es1"]);
d.card([Field::Blank]);
d.line("*DEFINE_CURVE_TITLE");
d.line(&format!("{name} hardening"));
d.header(&["lcid"]);
d.card([Field::from(lcid)]);
d.header(&["a1", "o1"]);
for p in points {
d.card([Field::from(p.strain), Field::from(p.stress)]);
}
}
_ => return Err(broken(format!("material `{name}`: a plasticity LS-DYNA cannot take"))),
}
Ok(())
}
fn parts(d: &mut Deck, plan: &Plan) -> Result<()> {
for p in &plan.parts {
match p.section.kind {