4
$\begingroup$

I'm using ImportMesh in FEMAddOns package. When I imported the following mesh created in Abaqus

enter image description here

the following warning occurred:

ToElementMesh::femimq: The element mesh has insufficient quality of 0.`. A quality estimate below 0. may be caused by a wrong ordering of element incidents or self-intersecting elements.

Did I do something wrong?

.inp file:

*Heading
** Job name: qyyjianhua Model name: Model-1
** Generated by: Abaqus/CAE 2021
*Preprint, echo=NO, model=NO, history=NO, contact=NO
**
** PARTS
**
*Part, name=Part-1
*End Part
**  
**
** ASSEMBLY
**
*Assembly, name=Assembly
**  
*Instance, name=Part-1-1, part=Part-1
*Node
      1,           2.,           0.
      2,           0.,           0.
      3,         -10.,          20.
      4,          10.,          20.
      5,         -10.,         -20.
      6,           8.,           0.
      7,          10.,           0.
      8,          10.,         -20.
      9,   1.73205078,           1.
     10,           1.,   1.73205078
     11,           0.,           2.
     12,          -1.,   1.73205078
     13,  -1.73205078,           1.
     14,          -2.,           0.
     15,  -1.73205078,          -1.
     16,          -1.,  -1.73205078
     17,           0.,          -2.
     18,           1.,  -1.73205078
     19,   1.73205078,          -1.
     20,   5.80853033,          20.
     21,  0.460017532,          20.
     22,  -4.81056213,          20.
     23,         -10.,   15.2503662
     24,         -10.,   10.5661907
     25,         -10.,   5.77517176
     26,         -10., 0.000233809158
     27,         -10.,  -5.78195906
     28,         -10.,  -10.4485788
     29,         -10.,  -15.2008629
     30,   -5.4511385,         -20.
     31, -0.266591698,         -20.
     32,   4.89586306,         -20.
     33,          10.,  -15.2480021
     34,          10.,  -10.5735025
     35,          10.,  -5.77517176
     36,           9.,           0.
     37,   6.76777697,   4.26581717
     38,   3.84405661,   7.01592684
     39,  0.126907557,    7.9989934
     40,  -3.68013692,   7.10328054
     41,  -6.75329113,   4.28871298
     42,          -8., -0.00162268954
     43,    -6.779356,  -4.24739122
     44,  -3.84456635,  -7.01564741
     45,  -0.10826461,  -7.99926758
     46,   3.67319083,  -7.10687494
     47,   6.72185373,  -4.33782005
     48,          10.,   5.78195906
     49,          10.,   10.4810152
     50,          10.,   15.2338905
     51,  -8.04919815,   5.55550385
     52,  -8.91226673, 0.00748880301
     53,  0.235863537,   11.5949564
     54,   0.38208425,   15.5542936
     55,  -8.02860165,  -5.55888891
     56,   7.90317488,   5.71555376
     57, -0.219827414,  -15.5265503
     58, -0.155475363,  -11.5651379
     59,   7.83845663,  -5.81884718
     60,  -5.17192221,   10.6761541
     61,  -4.89879417,   15.3694239
     62,   5.46685171,   10.4651871
     63,   5.68823671,   15.3231401
     64,  -5.45252848,  -10.4385748
     65,  -5.34113503,  -15.2527342
     66,   5.18739414,  -10.7079449
     67,   4.96575165,  -15.3679714
     68,           2.,           0.
     69,           8.,           0.
     70,           9.,           0.
     71,          10.,           0.
     72,   1.93185163,  0.517638087
     73,  0.433012694,         0.25
     74,          0.5,           0.
     75,   1.41421354,   1.41421354
     76,         0.25,  0.433012694
     77,           0.,          0.5
     78,  0.517638087,   1.93185163
     79, -0.517638087,   1.93185163
     80,        -0.25,  0.433012694
     81,  -1.41421354,   1.41421354
     82, -0.433012694,         0.25
     83,         -0.5,           0.
     84,  -1.93185163,  0.517638087
     85,  -1.93185163, -0.517638087
     86, -0.433012694,        -0.25
     87,  -1.41421354,  -1.41421354
     88,        -0.25, -0.433012694
     89,           0.,         -0.5
     90, -0.517638087,  -1.93185163
     91,  0.517638087,  -1.93185163
     92,         0.25, -0.433012694
     93,   1.41421354,  -1.41421354
     94,  0.433012694,        -0.25
     95,          0.5,           0.
     96,   1.93185163, -0.517638087
     97,  -7.40124464,   4.92210865
     98,  -8.48073196,   2.78149629
     99,  -8.45613289, 0.00293305679
    100,  -7.68222904,    2.2323432
    101,  -9.02459908,   5.66533756
    102,         -10.,    2.8877027
    103,  -9.45613289,  0.003861306
    104,         -10.,     8.170681
    105,  -6.61056042,   8.11582947
    106,  -7.58596134,    10.621172
    107,  -5.40319824,   5.89961433
    108,  -4.42602968,    8.8897171
    109,  -1.83219409,   7.78736591
    110,  0.181385547,   9.79697514
    111,  -2.46802926,   11.1355553
    112,  0.308973908,    13.574625
    113,   -2.2583549,   15.4618587
    114,  -5.03535843,    13.022789
    115,  0.421050906,   17.7771473
    116,  -2.17527223,          20.
    117,  -4.85467815,   17.6847115
    118,  -7.40528107,          20.
    119,         -10.,   17.6251831
    120,  -7.44939709,   15.3098946
    121,         -10.,   12.9082785
    122,   -9.0143013,  -5.67042398
    123,  -8.47043419,  -2.77570009
    124,         -10.,   -2.8908627
    125,  -7.40397882,  -4.90314007
    126,  -7.68856144,  -2.21043491
    127,   5.48119783,   5.82721806
    128,   7.33547592,   4.99068546
    129,   6.68501329,   8.09037018
    130,   4.65545416,   8.74055672
    131,   8.95158768,   5.74875641
    132,          10.,   8.13148689
    133,   7.73342609,   10.4731007
    134,          10.,   12.8574524
    135,   7.84411812,   15.2785149
    136,   5.57754421,   12.8941631
    137,          10.,   17.6169453
    138,    7.9042654,          20.
    139,   5.74838352,   17.6615696
    140,   3.13427401,          20.
    141,   3.03516054,   15.4387169
    142,    2.8513577,   11.0300713
    143,   2.04542017,     7.734097
    144,  -5.48932981,  -5.81955814
    145,   -6.7405653,  -7.99873161
    146,  -4.64854717,  -8.72711086
    147,         -10.,  -8.11526871
    148,    -7.726264,  -10.4435768
    149,         -10.,  -12.8247204
    150,  -7.67056751,   -15.226799
    151,  -5.39683151,  -12.8456545
    152,         -10.,  -17.6004314
    153,  -7.72556925,         -20.
    154,  -5.39613676,  -17.6263676
    155,  -2.85886502,         -20.
    156, -0.243209556,  -17.7632751
    157,  -2.78048134,  -15.3896427
    158, -0.187651396,  -13.5458441
    159,  -2.80400181,  -11.0018559
    160, -0.131869987,  -9.78220272
    161,  -2.03668737,  -7.73640108
    162,   8.45158768,   2.85777688
    163,          9.5,           0.
    164,          10.,   2.89097953
    165,    7.6857729,   2.22011089
    166,          8.5,           0.
    167,          10.,  -8.17433739
    168,   8.91922855,  -5.79700947
    169,   6.51292515,  -8.26339626
    170,   7.59369707,  -10.6407242
    171,   7.28015518,  -5.07833385
    172,   5.37876892,   -5.9218955
    173,   4.43029261,  -8.90740967
    174,   1.83746183,  -7.78612471
    175,    2.5159595,  -11.1365414
    176,     2.372962,  -15.4472609
    177,    5.0765729,  -13.0379581
    178,   2.31463575,         -20.
    179,   4.93080711,  -17.6839867
    180,   7.44793129,         -20.
    181,          10.,  -17.6240005
    182,   7.48287582,  -15.3079872
    183,          10.,  -12.9107523
    184,   8.41922855,  -2.90942359
    185,          8.5,           0.
    186,   7.67381334,  -2.26110268
    187,          10.,  -2.88758588
    188,          9.5,           0.
    189,           5.,           0.
    190,   4.22695208,  -2.66891003
    191,   2.33659554,  -4.41946268
    192, -0.0541323051,  -4.99963379
    193,  -2.42228317,  -4.37384892
    194,  -4.25570345,  -2.62369561
    195,          -5., -0.000811344769
    196,  -4.24267101,   2.64435649
    197,  -2.34006834,   4.41766548
    198, 0.0634537786,   4.99949646
    199,    2.4220283,   4.37398863
    200,   4.24991369,   2.63290858
    201,           5.,           0.
    202,           0.,           0.
    203,           0.,           0.
    204,           0.,           0.
    205,           0.,           0.
    206,           0.,           0.
    207,           0.,           0.
    208,           0.,           0.
    209,           0.,           0.
    210,           0.,           0.
    211,           0.,           0.
    212,           0.,           0.
    213,           0.,           0.
    214,           0.,           0.
    215,           0.,           0.
    216,           0.,           0.
    217,           0.,           0.
    218,           0.,           0.
    219,           0.,           0.
    220,           0.,           0.
    221,           0.,           0.
    222,           0.,           0.
    223,           0.,           0.
    224,           0.,           0.
    225,           0.,           0.
*Element, type=CPS8R
 1,  41,  51,  52,  42,  97,  98,  99, 100
 2,  51,  25,  26,  52, 101, 102, 103,  98
 3,  24,  25,  51,  60, 104, 101, 105, 106
 4,  51,  41,  40,  60,  97, 107, 108, 105
 5,  40,  39,  53,  60, 109, 110, 111, 108
 6,  53,  54,  61,  60, 112, 113, 114, 111
 7,  54,  21,  22,  61, 115, 116, 117, 113
 8,  22,   3,  23,  61, 118, 119, 120, 117
 9,  61,  23,  24,  60, 120, 121, 106, 114
10,  27,  55,  52,  26, 122, 123, 103, 124
11,  55,  43,  42,  52, 125, 126,  99, 123
12,  38,  37,  56,  62, 127, 128, 129, 130
13,  56,  48,  49,  62, 131, 132, 133, 129
14,  49,  50,  63,  62, 134, 135, 136, 133
15,  50,   4,  20,  63, 137, 138, 139, 135
16,  20,  21,  54,  63, 140, 115, 141, 139
17,  63,  54,  53,  62, 141, 112, 142, 136
18,  53,  39,  38,  62, 110, 143, 130, 142
19,  44,  43,  55,  64, 144, 125, 145, 146
20,  55,  27,  28,  64, 122, 147, 148, 145
21,  28,  29,  65,  64, 149, 150, 151, 148
22,  29,   5,  30,  65, 152, 153, 154, 150
23,  30,  31,  57,  65, 155, 156, 157, 154
24,  65,  57,  58,  64, 157, 158, 159, 151
25,  58,  45,  44,  64, 160, 161, 146, 159
26,  48,  56,  70,  71, 131, 162, 163, 164
27,  56,  37,  69,  70, 128, 165, 166, 162
28,  34,  35,  59,  66, 167, 168, 169, 170
29,  59,  47,  46,  66, 171, 172, 173, 169
30,  46,  45,  58,  66, 174, 160, 175, 173
31,  58,  57,  67,  66, 158, 176, 177, 175
32,  57,  31,  32,  67, 156, 178, 179, 176
33,  32,   8,  33,  67, 180, 181, 182, 179
34,  67,  33,  34,  66, 182, 183, 170, 177
35,  47,  59,  36,   6, 171, 184, 185, 186
36,  59,  35,   7,  36, 168, 187, 188, 184
37,   6,   1,  19,  47, 189,  96, 190, 186
38,  47,  19,  18,  46, 190,  93, 191, 172
39,  46,  18,  17,  45, 191,  91, 192, 174
40,  45,  17,  16,  44, 192,  90, 193, 161
41,  44,  16,  15,  43, 193,  87, 194, 144
42,  43,  15,  14,  42, 194,  85, 195, 126
43,  42,  14,  13,  41, 195,  84, 196, 100
44,  41,  13,  12,  40, 196,  81, 197, 107
45,  40,  12,  11,  39, 197,  79, 198, 109
46,  39,  11,  10,  38, 198,  78, 199, 143
47,  38,  10,   9,  37, 199,  75, 200, 127
48,  37,   9,  68,  69, 200,  72, 201, 165
49,  68,   9,   2, 202,  72,  73, 214,  74
50, 203,   2,   9,  10, 215,  73,  75,  76
51,  11, 204, 203,  10,  77, 216,  76,  78
52,  11,  12, 205, 204,  79,  80, 217,  77
53, 206, 205,  12,  13, 218,  80,  81,  82
54,  14, 207, 206,  13,  83, 219,  82,  84
55,  14,  15, 208, 207,  85,  86, 220,  83
56, 209, 208,  15,  16, 221,  86,  87,  88
57,  17, 210, 209,  16,  89, 222,  88,  90
58,  17,  18, 211, 210,  91,  92, 223,  89
59, 212, 211,  18,  19, 224,  92,  93,  94
60,   1, 213, 212,  19,  95, 225,  94,  96
*Nset, nset=Set-1, generate
   1,  225,    1
*Elset, elset=Set-1, generate
  1,  60,   1
** Section: Section-1
*Solid Section, elset=Set-1, material=Material-1
,
*End Instance
**  
*Nset, nset=Set-1, instance=Part-1-1
   1,   6,   7,  36,  68,  69,  70,  71,  74,  95, 163, 166, 185, 188, 189, 201
 202, 213
*Elset, elset=Set-1, instance=Part-1-1
 26, 27, 35, 36, 37, 48, 49, 60
*Nset, nset=Set-5, instance=Part-1-1
   5,   8,  30,  31,  32, 153, 155, 178, 180
*Elset, elset=Set-5, instance=Part-1-1
 22, 23, 32, 33
*Nset, nset=_PickedSet6, internal, instance=Part-1-1
   1,   2,   9,  10,  11,  12,  13,  14,  15,  16,  17,  18,  19,  68,  72,  73
  74,  75,  76,  77,  78,  79,  80,  81,  82,  83,  84,  85,  86,  87,  88,  89
  90,  91,  92,  93,  94,  95,  96, 202, 203, 204, 205, 206, 207, 208, 209, 210
 211, 212, 213, 214, 215, 216, 217, 218, 219, 220, 221, 222, 223, 224, 225
*Elset, elset=_PickedSet6, internal, instance=Part-1-1, generate
 49,  60,   1
*Nset, nset=_PickedSet7, internal, instance=Part-1-1
 2,
*Elset, elset=_Surf-1_S2, internal, instance=Part-1-1
  7, 15
*Elset, elset=_Surf-1_S1, internal, instance=Part-1-1
  8, 16
*Surface, type=ELEMENT, name=Surf-1
_Surf-1_S2, S2
_Surf-1_S1, S1
*Nset, nset=_PickedSet6-1_, internal, instance=Part-1-1
   1,   2,   9,  10,  11,  12,  13,  14,  15,  16,  17,  18,  19,  68,  72,  73
  74,  75,  76,  77,  78,  79,  80,  81,  82,  83,  84,  85,  86,  87,  88,  89
  90,  91,  92,  93,  94,  95,  96, 202, 203, 204, 205, 206, 207, 208, 209, 210
 211, 212, 213, 214, 215, 216, 217, 218, 219, 220, 221, 222, 223, 224, 225
*Nset, nset=_PickedSet7-1_, internal, instance=Part-1-1
 2,
*End Assembly
** 
** MATERIALS
** 
*Material, name=Material-1
*Elastic
21000., 0.3
** ----------------------------------------------------------------
** 
** STEP: Step-1
** 
*Step, name=Step-1, nlgeom=YES
*Static
1., 1., 1e-05, 1.
** 
** BOUNDARY CONDITIONS
** 
** Name: BC-1 Type: 对称/反对称/完全固定
*Boundary
Set-5, PINNED
** 
** LOADS
** 
** Name: Load-1   Type: Pressure
*Dsload
Surf-1, P, -100.
** 
** OUTPUT REQUESTS
** 
*Restart, write, frequency=0
** 
** FIELD OUTPUT: F-Output-1
** 
*Output, field, variable=PRESELECT
*Output, history, frequency=0
** 
** HISTORY OUTPUT: H-Output-1
** 
*Contour Integral, crack name=H-Output-1_Crack-1, contours=5, crack tip nodes, type=K FACTORS
_PickedSet6-1_, _PickedSet7-1_, -1., 0., 0.
*End Step
$\endgroup$
4
  • 5
    $\begingroup$ Please include the .inp file you failed to import in the question. (The .inp file can be opened with any text editor, you can simply copy&paste the content inside it into the question. ) $\endgroup$ – xzczd Mar 28 at 1:26
  • $\begingroup$ As requested in my last comment, please include the whole file in your question, otherwise we cannot test. $\endgroup$ – xzczd Mar 28 at 8:10
  • $\begingroup$ it is too long ,i can not copy $\endgroup$ – sgzslg Mar 28 at 8:29
  • $\begingroup$ Then you should simplify your mesh to create a minimal example that reproduces the issue. $\endgroup$ – xzczd Mar 28 at 8:29
5
$\begingroup$

This is more of an issue of ImportMesh than anything else. In principal it could collapse elements. But you can do this yourself:

Needs["FEMAddOns`"]
mesh = ImportMesh["test.inp"]

ToElementMesh::femimq: The element mesh has insufficient quality of 0.`. A quality estimate below 0. may be caused by a wrong ordering of element incidents or self-intersecting elements.

Now, we reconstruct the mesh with collapsed elements:

{tri, quad} = 
  SplitBy[SortBy[
    DeleteDuplicates /@ 
     Join @@ ElementIncidents[mesh["MeshElements"]], Length], 
   Length];
mesh2 = ToElementMesh["Coordinates" -> mesh["Coordinates"], 
   "MeshElements" -> {TriangleElement[tri], QuadElement[quad]}];
mesh2["Wireframe"]

enter image description here

This currently does not take care of the markers but that's not impossible to do either.

$\endgroup$
4
$\begingroup$

The underlying issue is essentially the same as indicated in user21's answer under your previous question. The last 12 elements in your mesh have made use of 2nd node for multiple times, thus their qualities are 0:

Needs["FEMAddOns`"]

mesh = ImportMesh@(* file path *)

(* ToElementMesh::femimq *)

mesh@"Quality"
(*
 …… 0., 0., 0., 0., 0., 0., 0., 0., 0., 0., 0., 0.}}
 *)

mesh["MeshElements"][[1, 1, -12 ;;]]
(* {{1,  9,  2,  2,  68, 69, 2,  70}, {2,  2,  9,  10, 2,  69, 71, 72}, 
    {11, 2,  2,  10, 73, 2,  72, 74}, {11, 12, 2,  2,  75, 76, 2,  73}, 
    {2,  2,  12, 13, 2,  76, 77, 78}, {14, 2,  2,  13, 79, 2,  78, 80}, 
    {14, 15, 2,  2,  81, 82, 2,  79}, {2,  2,  15, 16, 2,  82, 83, 84}, 
    {17, 2,  2,  16, 85, 2,  84, 86}, {17, 18, 2,  2,  87, 88, 2,  85}, 
    {2,  2,  18, 19, 2,  88, 89, 90}, {1,  2,  2,  19, 70, 2,  90, 91}} *)

I know nothing about Abaqus and don't know if this mesh is legal therein, but it's not allowed in Mathematica, at least now:

With[{u = u[x, y]}, 
 NDSolveValue[{-Laplacian[u, {x, y}] == 1, DirichletCondition[u == 0, True]}, 
  u, {x, y} ∈ mesh]]

(* ElementMeshInterpolation::fememtlq *)
(* Unevaluated ElementMeshInterpolation[…] returned. *)

wrongindex = {1, 2, 2, 19, 70, 2, 90, 91};

wrongcoord = mesh["Coordinates"][[wrongindex]]

ToElementMesh["Coordinates" -> wrongcoord, "MeshElements" -> {QuadElement@{wrongindex}}]

(* ToElementMesh::fembdel *)    
(* ToElementMesh::femtemnm: A mesh could not be generated. *)
(* $Failed *)

Anyway, for this specific problem, it's easy to repair the mesh, all we need to do is to remove the duplicate nodes and use TriangleElement to rebuild these elements:

{trindex, quadindex} = 
 GatherBy[DeleteDuplicates /@ mesh["MeshElements"][[1, 1]] // Sort, Length]

repairedmesh = 
 ToElementMesh["Coordinates" -> mesh["Coordinates"], 
  "MeshElements" -> {QuadElement@quadindex, TriangleElement@trindex}]
$\endgroup$
1
  • $\begingroup$ Thank you very much for answering my question! $\endgroup$ – sgzslg Mar 29 at 10:51

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