forked from 1b-agent/fieldcraft-upstream
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