{
 "title": "Scordelis–Lo roof with shell elements",
 "kind": "benchmark",
 "source": "MacNeal and Harder, 'A proposed standard set of problems to test finite element accuracy', Finite Elements in Analysis and Design 1 (1985) 3–20, Fig. 8 (p. 8), Table 5(a) (p. 11); Belytschko, Stolarski, Liu, Carpenter and Ong, 'Stress projection for membrane and shear locking in shell finite elements', Computer Methods in Applied Mechanics and Engineering 51 (1985) 221–258 (the shell obstacle course)",
 "quantities": [
  {
   "id": "uz",
   "quantity": "vertical displacement at the midpoint of the free edge, mid-surface",
   "measure": {
    "command": "solve.probe",
    "params": {
     "step": "Load",
     "at": [
      [
       0,
       16.069690242163,
       19.151111077974
      ]
     ]
    },
    "pointer": "/nodes/0/displacement/2"
   },
   "value": -0.3024,
   "tolerance": {
    "relative": 0.02
   },
   "reason": "MacNeal and Harder grade a thin-shell element within 2% of the theoretical value on a prescribed coarse mesh, the grading the sibling case scordelis-lo-roof-solid records (p. 14); this case uses 16 × 16, the mesh the solver's in-code gate test uses, and the flat MITC4 shell converges from below to the reference: 4 × 4, 8 × 8, 16 × 16, 32 × 32, 64 × 64 and 128 × 128 give 0.28459, 0.29401, 0.29901, 0.30060, 0.30118 and 0.30143, so 16 × 16 is 1.12% low and the mesh error shrinks monotonically inside the tolerance (README)"
  }
 ]
}