forked from 1b-agent/fieldcraft-upstream
Christian Svensson
a8040063a6
The thin-walled cylinder with a hemispherical cap under internal pressure as four axisymmetric quad8 blocks: axial stress on the outer surface at D 25.283. The NAFEMS target, 25.86, is the axisymmetric thin-shell solution; our solid model converges to 25.27, the value ESRD reports for its converged axisymmetric solid. So the NAFEMS quantity keeps a 1% tolerance and is a known failure until there is an axisymmetric shell element, and a second quantity checks the model against the solid reference (pass, 0.05%). Part of #97.
25 lines
1.8 KiB
JSON
25 lines
1.8 KiB
JSON
{
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"title": "NAFEMS LE7 axisymmetric cylinder/sphere under pressure (axisymmetric quad8)",
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"kind": "benchmark",
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"source": "NAFEMS, The Standard NAFEMS Benchmarks, TNSB Rev. 3, October 1990, test LE7 (target: axial stress 25.86 MPa on the outer surface at D, R = 1.0125, Z = 1.4034), as reproduced in the ESRD StressCheck Benchmarks Guide 'The Standard NAFEMS Benchmarks: Linear Elastic Tests' (2018), p. 23, which also gives its converged axisymmetric solid result, 25.27 MPa (p. 24); the Abaqus 2016 Benchmarks Guide, section 4.2.7 'LE7: Axisymmetric cylinder/sphere under pressure', gives the target rounded to 25.9 MPa",
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"quantities": [
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{
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"id": "syy_D",
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"quantity": "axial stress σ_yy at D (1.0125, 1.4034), outer surface",
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"measure": {"command": "solve.probe", "params": {"step": "Pressure", "at": [[1.0125, 1.4034, 0]]}, "pointer": "/nodes/0/stress/1"},
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"value": 25.86,
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"tolerance": {"relative": 0.01},
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"reason": "the target is published to four figures for the thin-shell model of the vessel, and a model of the same theory converges well within 1%",
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"known_failure": "the target is the axisymmetric thin-shell solution and FieldCraft has no axisymmetric shell element; our axisymmetric solid model converges to 25.27 (−2.3%), the value ESRD reports for its converged axisymmetric solid (quantity syy_D_solid)"
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},
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{
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"id": "syy_D_solid",
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"quantity": "axial stress σ_yy at D (1.0125, 1.4034), outer surface, against the converged solid model",
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"measure": {"command": "solve.probe", "params": {"step": "Pressure", "at": [[1.0125, 1.4034, 0]]}, "pointer": "/nodes/0/stress/1"},
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"value": 25.27,
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"tolerance": {"relative": 0.01},
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"reason": "the same model idealisation (axisymmetric solid) as the reference, which ESRD reports converged to under 1% on two meshes; ours moves by 0.05% on the next refinement (see README)"
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}
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]
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}
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