{ "title": "Nonlinear patch test, hex8: a homogeneous finite deformation of a distorted mesh", "kind": "theory", "source": "The patch test (B. M. Irons, A. Razzaque, in A. K. Aziz (ed.), The Mathematical Foundations of the Finite Element Method, Academic Press 1972, 557–587) at finite strain: a boundary moved by x = F X makes F the solution everywhere (J. Bonet, R. D. Wood, Nonlinear Continuum Mechanics for Finite Element Analysis, 2nd ed., Cambridge 2008, §8); the neo-Hookean Cauchy stress σ = μ J^(−5/3) dev b + κ (J − 1) I of that F", "quantities": [ { "id": "ux", "quantity": "u_x at inner node 22", "measure": { "command": "solve.probe", "params": { "step": "Deform", "nodes": [ 22 ] }, "pointer": "/nodes/0/displacement/0" }, "value": 0.13583340405268285, "tolerance": { "relative": 1e-08 }, "reason": "a patch test is passed exactly: the tolerance admits rounding and the Newton tolerance" }, { "id": "uy", "quantity": "u_y at inner node 22", "measure": { "command": "solve.probe", "params": { "step": "Deform", "nodes": [ 22 ] }, "pointer": "/nodes/0/displacement/1" }, "value": 0.0003487491373645457, "tolerance": { "relative": 1e-08 }, "reason": "a patch test is passed exactly: the tolerance admits rounding and the Newton tolerance" }, { "id": "uz", "quantity": "u_z at inner node 22", "measure": { "command": "solve.probe", "params": { "step": "Deform", "nodes": [ 22 ] }, "pointer": "/nodes/0/displacement/2" }, "value": -0.002398508020922785, "tolerance": { "relative": 1e-08 }, "reason": "a patch test is passed exactly: the tolerance admits rounding and the Newton tolerance" }, { "id": "sxx", "quantity": "Cauchy σ_xx at inner node 22", "measure": { "command": "solve.probe", "params": { "step": "Deform", "nodes": [ 22 ] }, "pointer": "/nodes/0/stress/0" }, "value": 42.29617970634737, "tolerance": { "relative": 1e-07 }, "reason": "a patch test is passed exactly: the tolerance admits rounding and the Newton tolerance" }, { "id": "syy", "quantity": "Cauchy σ_yy at inner node 22", "measure": { "command": "solve.probe", "params": { "step": "Deform", "nodes": [ 22 ] }, "pointer": "/nodes/0/stress/1" }, "value": 23.501008557686546, "tolerance": { "relative": 1e-07 }, "reason": "a patch test is passed exactly: the tolerance admits rounding and the Newton tolerance" }, { "id": "szz", "quantity": "Cauchy σ_zz at inner node 22", "measure": { "command": "solve.probe", "params": { "step": "Deform", "nodes": [ 22 ] }, "pointer": "/nodes/0/stress/2" }, "value": 31.452811735966126, "tolerance": { "relative": 1e-07 }, "reason": "a patch test is passed exactly: the tolerance admits rounding and the Newton tolerance" }, { "id": "sxy", "quantity": "Cauchy σ_xy at inner node 22", "measure": { "command": "solve.probe", "params": { "step": "Deform", "nodes": [ 22 ] }, "pointer": "/nodes/0/stress/3" }, "value": -0.8897122437235885, "tolerance": { "relative": 1e-07 }, "reason": "a patch test is passed exactly: the tolerance admits rounding and the Newton tolerance" }, { "id": "sxz", "quantity": "Cauchy σ_xz at inner node 22", "measure": { "command": "solve.probe", "params": { "step": "Deform", "nodes": [ 22 ] }, "pointer": "/nodes/0/stress/4" }, "value": -1.8906385179126266, "tolerance": { "relative": 1e-07 }, "reason": "a patch test is passed exactly: the tolerance admits rounding and the Newton tolerance" }, { "id": "syz", "quantity": "Cauchy σ_yz at inner node 22", "measure": { "command": "solve.probe", "params": { "step": "Deform", "nodes": [ 22 ] }, "pointer": "/nodes/0/stress/5" }, "value": 1.9462455331453503, "tolerance": { "relative": 1e-07 }, "reason": "a patch test is passed exactly: the tolerance admits rounding and the Newton tolerance" } ] }