# Standard order: docs/maintainer/CONFIGURATION_STYLE.md.
# 1. Identity and evidence boundary; beta teaching input, not physical validation.
schema_version: 2
name: DCB-style opening with a tough inclusion inside a weak bulk layer
reference: Qualitative confined-layer AT2 teaching model; not experimental calibration or a cohesive-interface model
# 2. Geometry [mm] and mesh: nx/ny count cells split into T3 triangles.
# Dimension changes require corresponding boundary/crack/material-selector edits.
geometry:
  type: structured_rectangle
  units: mm
  parameters: {length: 6.0, height: 1.2, origin: [0.0, -0.6], nx: 160, ny: 48}
# 3. Materials select element centroids; constraints select nodes.
# Keep circle and all complementary outside_circle selectors consistent.
# Crack thickness is a selection distance, not a physical opening.
regions:
  material_1_region:
    kind: element_region
    type: all_of
    selectors:
      - {type: outside_circle, center: [2.2, 0.0], radius: 0.20}
      - type: not
        selector: {type: rectangle, origin: [0.0, -0.30], size: [6.0, 0.60]}
  weak_midline_region:
    kind: element_region
    type: all_of
    selectors:
      - {type: rectangle, origin: [0.0, -0.30], size: [6.0, 0.60]}
      - {type: outside_circle, center: [2.2, 0.0], radius: 0.20}
  material_2_region: {kind: element_region, type: circle, center: [2.2, 0.0], radius: 0.20}
  initial_crack: {kind: node_region, type: line_segment, from: [0.0, 0.0], to: [1.5, 0.0], thickness: 0.012}
  right_clamp: {kind: node_region, type: boundary, side: right, tolerance: 1.0e-8}
  upper_load: {kind: node_region, type: boundary_segment, axis: x, value: 0.0, bounds: {y: [0.30, 0.60]}, tolerance: 1.0e-8}
  lower_load: {kind: node_region, type: boundary_segment, axis: x, value: 0.0, bounds: {y: [-0.60, -0.30]}, tolerance: 1.0e-8}
# 4. E [MPa] is stiffness; Gc [N/mm] is fracture resistance; l0 [mm].
# Equal E isolates toughness contrast. This route varies elementwise E/Gc only.
# Keep nu/l0/model/split/plane-stress and shared settings consistent.
# rho is illustrative: quasi-static equilibrium omits inertia.
materials:
  material_1:
    model: phase_field
    parameters: {E: 5000.0, nu: 0.30, Gc: 1.0, l0: 0.10, rho: 1.0, eta_residual: 1.0e-6, energy_split: amor, pf_model: AT2, plane_stress: true}
  weak_midline:
    model: phase_field
    parameters: {E: 5000.0, nu: 0.30, Gc: 0.04, l0: 0.10, rho: 1.0, eta_residual: 1.0e-6, energy_split: amor, pf_model: AT2, plane_stress: true}
  material_2:
    model: phase_field
    parameters: {E: 5000.0, nu: 0.30, Gc: 0.12, l0: 0.10, rho: 1.0, eta_residual: 1.0e-6, energy_split: amor, pf_model: AT2, plane_stress: true}
# 5. Every element receives one material: no gaps or overlaps.
assignments:
  - {material: material_1, region: material_1_region}
  - {material: weak_midline, region: weak_midline_region}
  - {material: material_2, region: material_2_region}
# 6. Prescribed damage values are maintained; no future crack path is imposed.
initial_conditions:
  - {field: damage, region: initial_crack, value: 1.0}
# 7. Dirichlet conditions prescribe displacements [mm] or fix components.
boundary_conditions:
  - {name: clamp_x, type: fix, region: right_clamp, dof: x}
  - {name: clamp_y, type: fix, region: right_clamp, dof: y}
  - {name: open_upper, type: prescribe, region: upper_load, dof: y, value: 0.15}
  - {name: open_lower, type: prescribe, region: lower_load, dof: y, value: -0.15}
# 8. Quasi-static load levels, not physical time; the count includes zero.
analysis_steps:
  - name: opening
    type: quasi_static
    active_boundary_conditions: [clamp_x, clamp_y, open_upper, open_lower]
    # 121 levels include zero: 120 nominal increments before any cutbacks.
    controls: {number_of_steps: 121}
# 9. CPU float64 staggered Amor AT2 controls. Iterations are not load steps.
# Algebraic convergence and h/l0 alone do not establish physical validation.
solver:
  type: quasi_static
  mechanics_backend: auto
  mechanics_tolerance: 1.0e-9
  mechanics_relative_tolerance: 1.0e-8
  mechanics_max_iterations: 30
  damage_tolerance: 1.0e-8
  damage_max_iterations: 500
  damage_bounds_method: projected_cg
  maximum_staggered_iterations: 500
  staggered_damage_tolerance: 1.0e-5
  projected_residual_tolerance: 1.0e-5
  damage_relaxation: 0.70
  automatic_cutback: true
  minimum_load_increment: 0.00025
  maximum_cutbacks: 40
  crack_front_threshold: 0.80
# 10. Output requests. Use a fresh directory for every comparison.
# HDF5 is the default when a trajectory is requested; keep raw stores local.
outputs:
  directory: runs/two_material_dcb
  fields:
    - {name: trajectory, format: h5, every: 1}
    - {name: displacement}
    - {name: strain}
    - {name: stress}
    - {name: damage}
    - {name: vtu}
  history:
    - {name: reaction_force, region: upper_load, dof: y}
    - {name: max_damage}
    - {name: solver_telemetry}
    - {name: timing_per_step}
  visuals:
    initial_conditions: true
    plots: true
    animation: {field: damage}