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Growing cohesive peel — Wells (2002) Fig. 9

Two neo-Hookean plies, fine mesh, L–L large-displacement interface. The right-hand corners are opened by ±u; a 1 mm traction-free starter crack sits at the right. The mid-plane follows Wells’ exponential cohesive law. Watch the process zone march left and the arms peel at true scale.

DCB cohesive crack · Cohesive zone · Single fiber RVE

Drag pan/rotate · Scroll zoom · plane-strain peel (×40)
Dummy elastic toe
u = 0 mm
P = 0 N
elastic toe
softening
debonded node
load node ±u
cohesive traction at every node
P–u · L–L fine (MATLAB Fig. 10)
FEM L–L fine Now u = 2, 6, left edge
0 peak ~0.2 2 Fig. 9 left edge ~8.5 mm
P (FEM)0.000 N
Crack a1.00 mm
Peak σ0.00 MPa
Max gn0.000 mm
Debonded nodes0 / 81
StateToe
Cohesive traction along the interface σ(x)
x = 0 clamped · rose = starter (x > 9) · amber = current front · arrows = cohesive force
Wells exponential law σ(gn)
Dummy toe to ft, then σ = ft exp(−ft(gn−gn0)/Gf) · dots = stations

Specimen (Sec. 6.2 / MATLAB)

  • L = 10 mm, plies 0.5 + 0.5 mm, plane strain
  • Fine mesh: 80 × 6 Q4 per ply (~960 elements)
  • Left x = 0 fully fixed; right corners uy = ±u
  • Starter crack a0 = 1 mm, traction-free, from the right
  • L–L: large-displacement interface + neo-Hookean bulk

Cohesive law (Wells Sec. 5)

  • ft = 1 MPa · Gf = 0.05 N/mm
  • Dummy toe (2% of Gf): gn0 = 0.002 mm, kn = 500 MPa/mm
  • Then exponential softening; released when κ ≥ −ln(0.02) Gf/ft
  • P–u is the MATLAB L–L fine history; the mesh is a large-rotation peel with the same CZM