I am a Civil Engineering student at the University of Dundee
currently undertaking a project to model the bio mechanics of the
human cornea. In doing this I hope to relate experimental results to
abaqus finite element displacedments.
Unfortunately I am encountering problems related to the model which
may be seen below. The problem is that the 2D cornea which has been
modelled is required to be deformed under a load from a piece of
equipment, which must come into contact with the cornea and flatten a
small area. The model is producing no error or warning messages in
the .dat or .msg files, this suggests to me that there is a problem
in changing the boundary conditions to allow movement of the
applanating device, which I have tried to solve but have not managed
to.
Thank you for your assistance
Colin Fyfe
*HEADING
Linear Elastic Model with Indentor
**DEFINE ANTERIOR AND POSTERIOR SURFACES**
**ANTERIOR**
*RESTART, WRITE
*NODE, NSET=CORNEA
1, 0, 5.5842813
2, 0.25, 5.582198
3, 0.5, 5.572113
4, 0.75, 5.554434
5, 1, 5.529416
6, 1.25, 5.497189
7, 1.5, 5.457794
8, 1.75, 5.411206
9, 2, 5.357356
10, 2.25, 5.296139
11, 2.5, 5.227424
12, 2.75, 5.151058
13, 3, 5.066858
14, 3.25, 4.974603
15, 3.5, 4.874018
16, 3.75, 4.764752
17, 4, 4.646352
18, 4.25, 4.518227
19, 4.5, 4.379613
20, 4.75, 4.229522
21, 5, 4.066699
22, 5.25, 3.889561
23, 5.5, 3.696135
24, 5.75, 3.48399
25, 6, 3.250165
26, 6.25, 2.991088
27, 6.5, 2.70249
28, 6.75, 2.379317
29, 7, 2.015626
30, 7.25, 1.604491
31, 7.5, 1.137887
32, 7.75, 0.60658
33, 8, 0
**POSTERIOR**
801, 0, 5.034281
802, 0.236357, 5.026428
803, 0.47243, 5.010914
804, 0.708229, 4.98816
805, 0.943763, 4.958429
806, 1.17904, 4.921861
807, 1.414071, 4.878507
808, 1.648865, 4.828353
809, 1.883434, 4.771337
810, 2.117786, 4.707364
811, 2.351934, 4.636311
812, 2.585888, 4.558034
813, 2.819661, 4.472359
814, 3.053263, 4.379071
815, 3.286707, 4.277903
816, 3.520005, 4.168512
817, 3.753169, 4.05045
818, 3.986213, 3.923134
819, 4.21915, 3.785805
820, 4.451992, 3.637482
821, 4.684753, 3.476914
822, 4.917448, 3.302524
823, 5.150089, 3.112343
824, 5.382691, 2.903945
825, 5.615268, 2.674372
826, 5.847834, 2.420056
827, 6.080404, 2.136731
828, 6.312993, 1.819344
829, 6.545616, 1.461957
830, 6.778287, 1.057644
831, 7.011021, 0.598382
832, 7.243834, 0.074938
833, 7.476741, -0.52325
**GENERATE NODES**
*NGEN, NSET=CORNEA
1, 801, 100
2, 802, 100
3, 803, 100
4, 804, 100
5, 805, 100
6, 806, 100
7, 807, 100
8, 808, 100
9, 809, 100
10, 810, 100
11, 811, 100
12, 812, 100
13, 813, 100
14, 814, 100
15, 815, 100
16, 816, 100
17, 817, 100
18, 818, 100
19, 819, 100
20, 820, 100
21, 821, 100
22, 822, 100
23, 823, 100
24, 824, 100
25, 825, 100
26, 826, 100
27, 827, 100
28, 828, 100
29, 829, 100
30, 830, 100
31, 831, 100
32, 832, 100
33, 833, 100
**GENERATE ELEMENTS**
*ELEMENT, TYPE=CAX4
1, 1, 101, 102, 2
*ELGEN, ELSET=CORNEA
1, 32, 1, 1, 8, 100, 100
**CORNEA SURFACE**
*ELSET, ELSET=EPITHELIUM
1, 32
**GENERATE NODES TONOPEN**
*NODE, NSET=TONOPEN
**BOTTOM**
1001, 0, 5.5842813
1002, 0.25, 5.5842813
**TOP**
1101, 0, 5.9
1102, 0.25, 5.9
*ELSET, ELSET=PENS
1000
**GENERATE ELEMENTS TONOPEN**
*ELEMENT, ELSET=TONOPEN, TYPE=CAX4
1000, 1001, 1002, 1102, 1101
**DEFINE MATERIAL PROPERTIES FOR CORNEA**
*SOLID SECTION, ELSET=CORNEA, MATERIAL=CORNEA
*MATERIAL, NAME=CORNEA
*ELASTIC
0.83, 0.495
**DEFINE MATERIAL PROPERTIES FOR TONOPEN**
*SOLID SECTION, ELSET=TONOPEN, MATERIAL=PEN
*MATERIAL, NAME=PEN
*ELASTIC
20000, 0.495
**INTERFACE SURFACES**
*SURFACE DEFINITION, NAME=BSURF
PENS
*SURFACE DEFINITION, NAME=ASURF
EPITHELIUM, S2
*CONTACT PAIR, INTERACTION=ROUGH
ASURF, BSURF
*SURFACE INTERACTION, NAME=ROUGH
*FRICTION, ROUGH
**DEFINE BOUNDARY CONDITIONS**
*BOUNDARY
1, 1
101, 1
201, 1
301, 1
401, 1
501, 1
601, 1
701, 1
801, 1
33, ENCASTRE
133, ENCASTRE
233, ENCASTRE
333, ENCASTRE
433, ENCASTRE
533, ENCASTRE
633, ENCASTRE
733, ENCASTRE
833, ENCASTRE
1001, 1
1002, 1
1101, 1
1102, 1
1102, 2
**APPLY LOAD TO TONOPEN**
*STEP
*ELSET, ELSET=ELLOAD
1000
*STATIC
*DLOAD
ELLOAD, P2, -200
*BOUNDARY
1, 1
101, 1
201, 1
301, 1
401, 1
501, 1
601, 1
701, 1
801, 1
33, ENCASTRE
133, ENCASTRE
233, ENCASTRE
333, ENCASTRE
433, ENCASTRE
533, ENCASTRE
633, ENCASTRE
733, ENCASTRE
833, ENCASTRE
1001, 1
1002, 1
1101, 1
1102, 1
*NODE PRINT, SUMMARY=NO
U
*ELPRINT, POSITION=AVERAGED AT NODES, SUMMARY=YES, FREQUENCY=0
*END STEP
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