schema_version: 1
example: phast.examples.dynamic_branching_pmma.run
problem:
  name: PMMA Dynamic Crack Branching
  reference: Bleyer, Roux-Langlois & Molinari (2017), Comput. Mech.
# Geometry uses the inline-primitive DSL. Plate (W=32, H=16, a=4)
# minus a triangular wedge notch (3-vertex polygon, edge-flush at x=0).
# `branching: true` is reproduced via a box refinement over the right-
# half band x in [a-5, W], y in [0, H]. Boundary node sets are defined
# with thin RegionGroup strips along each base edge. l0 = 0.1,
# h_crack = 0.02, h_coarse = 1.0, crack_band = 5*l0 = 0.5 — matches
# mesh_generator.rectangular_sent.
geometry:
  units: mm
  primitives:
    plate: { type: rectangle, origin: [0, 0], size: [32.0, 16.0] }
    # Triangular wedge notch: tip at (a, H/2)=(4, 8), mouth at left
    # edge spanning H/2 +- eps. eps = min(0.01*min(W,H), 0.01) = 0.01.
    notch:
      type: polygon
      vertices: [[0.0, 8.01], [4.0, 8.0], [0.0, 7.99]]
  domain:
    base: plate
    subtract: [notch]
  named_groups:
    left:   { region: { type: rectangle, origin: [-0.005, 0.0],   size: [0.01, 16.0] } }
    top:    { region: { type: rectangle, origin: [ 0.0,   15.995], size: [32.0, 0.01] } }
    bottom: { region: { type: rectangle, origin: [ 0.0,  -0.005],  size: [32.0, 0.01] } }
  mesh:
    element_size:
      default: 1.0       # h_coarse
      refined:
        # Distance+Threshold band around the notch curves (matches
        # Field[1]+Field[2] in legacy .geo: 5*l0 wide).
        - primitive: notch
          size: 0.02     # h_crack = l0/5
          margin: 0.5    # crack_band = 5*l0
        # Field[Box]: uniform fine mesh in the right half — required for
        # branching pattern resolution (Borden 2012 §4.2). Matches the
        # branching=true branch of mesh_generator.rectangular_sent.
        - region:
            type: box
            x: [-1.0, 32.0]   # a - 5 = -1
            y: [0.0, 16.0]
          size: 0.02
          thickness: 1.0
# Inline material — Bleyer et al. (2017) PMMA, plane stress, AT1 + Amor.
material:
  E: 3090.0             # 3.09 GPa
  nu: 0.35
  Gc: 0.3               # 0.3 N/mm = 300 J/m^2
  l0: 0.1
  rho: 1.18e-9
  energy_split: amor
  pf_model: AT1
  plane_stress: true
  eta_residual: 1.0e-7
loading:
  protocol: two_step_prestrain
  prestrain_displacement: 0.05
  coupled_prestrain: true
  t_total: 7.5e-05
  ramp_type: constant
solver:
  solver_type: explicit
  dt_safety: 0.8
  # Bleyer (2017) reproduction: damage solved every step. Subcycling
  # (damage_every=3) suppresses second-lobe nucleation at branching
  # threshold.
  damage_every: 1
output:
  trajectory: true
  trajectory_format: zarr
  h5_every: 20
  fast: true
  print_every: 100
boundary_conditions:
- nodes: left
  type: fix
  component: 0
- nodes: top
  type: prescribe
  component: 1
  value: 1.0
- nodes: bottom
  type: prescribe
  component: 1
  value: -1.0