forked from 1b-agent/fieldcraft-upstream
jyvikoandClaude Opus 5.5
6baa189231
One constant pressure per element (mean dilatation, Nagtegaal, Parks & Rice 1974; the hoop strain in the divergence) for quad4, quad8 and tri6: the linear stiffness, stresses and thermal load, and the finite- and small-strain forms of nonlinear steps with their consistent tangent. The linear triangle and plane stress are refused by name. Co-Authored-By: Claude Opus 5.5 <[email protected]> Claude-Session: https://claude.ai/code/session_01UhhZMBTviDQxZvwnyP89fo
Inflation of a stretched Mooney–Rivlin tube, axisymmetric
The tube of nl-mooney-rivlin-tube (A = 10, B = 20, one unit long; E = 3, ν = 0.4995,
C₀₁ = 0.2) as an axisymmetric model of 12 × 2 hybrid quad4 (one constant pressure each, the mean
dilatation with the hoop strain): the end y = 0 on a symmetry line, the end y = 1 stretched to
λ_z = 1.5 while the follower pressure p = 0.540850 inflates the bore. The closed form puts the
bore at a = 15 and the outer wall at b = 20.615528 (see nl-mooney-rivlin-tube); this case checks
the nearly incompressible 2D hybrid elements at large strain against it.