A constitutive model is developed to characterize a general class of polymer and polymer-like materials that displays hyperelastic orthotropic mechanical behavior. The strain energy function is derived from the entropy change associated with the deformation of constituent macromolecules and the strain energy change associated with the deformation of a representative orthotropic unit cell. The ability of this model to predict nonlinear, orthotropic elastic behavior is examined by comparing the theory to experimental results in the literature. Simulations of more complicated boundary value problems are performed using the finite element method.

1.
Lanir
,
Y.
, and
Fung
,
Y. C.
,
1974
, “
Two-Dimensional Mechanical Properties of Rabbit Skin—II: Experimental Results
,”
J. Biomech.
,
7
, pp.
171
182
.
2.
Lanir
,
Y.
,
1979
, “
A Structural Theory for the Homogeneous Biaxial Stress-Strain Relationships in Flat Collagenous Tissues
,”
J. Biomech.
,
12
, pp.
423
436
.
3.
Lanir
,
Y.
,
1979
, “
Biaxial Stress-Strain Relationship in the Skin
,”
Isr. J. Technol.
,
17
, pp.
78
85
.
4.
Humphrey
,
J. D.
,
Strumpf
,
R. K.
, and
Yin
,
F. C. P.
,
1992
, “
A Constitutive Theory for Biomembranes: Application to Epicardial Mechanics
,”
ASME J. Biomech. Eng.
,
114
, pp.
461
466
.
5.
Rodriguez
,
E. K.
,
Hoger
,
A.
, and
McCulloch
,
A. D.
,
1994
, “
Stress-Dependent Finite Growth in Soft Elastic Tissues
,”
J. Biomech.
,
27
(
4
), pp.
455
467
.
6.
Holzapfel
,
G. A.
,
Eberlein
,
R.
,
Wriggers
,
P.
, and
Weizsa¨cker
,
H. W.
,
1996
, “
Large Strain Analysis of Soft Biological Membranes: Formulation and Finite Element Analysis
,”
Comput. Methods Appl. Mech. Eng.
,
132
, pp.
45
61
.
7.
Humphrey, J. D., and Yin, F. C. P., 1987, “A New Approach for Describing Soft Tissue Behavior,” Proc. Thirteenth Annual NE Bioeng. Conf., IEEE, Piscataway, NJ, pp. 24–25.
8.
Humphrey
,
J. D.
,
Strumpf
,
R. K.
, and
Yin
,
F. C. P.
,
1990
, “
Determination of a Constitutive Relation for Passive Myocardium—I: A New Functional Form
,”
ASME J. Biomech. Eng.
,
112
, pp.
333
339
.
9.
Baumann
,
C. G.
,
Smith
,
S. B.
,
Bloomfield
,
V. A.
, and
Bustamente
,
C.
,
1997
, “
Ionic Effects on the Elasticity of Single DNA Molecules
,”
Proc. Natl. Acad. Sci. U.S.A.
,
94
, pp.
6185
6190
.
10.
Treloar, L. R. G., 1975, The Physics of Rubber Elasticity, Clarendon Press. Oxford, UK.
11.
Kuhn
,
W.
, and
Gru¨n
,
F.
,
1942
, “
Beziehungen Zwischen Elastischen Konstanten und Dehnungsdoppelbrechung Hochelastischer Stoffe
,”
Kolloid-Z.
,
101
, pp.
248
271
.
12.
Kellermayer
,
M. S. Z.
,
Smith
,
S. B.
,
Bustamente
,
C.
, and
Granzier
,
H. L.
,
1998
, “
Complete Unfolding of the Titin Molecule Under External Force
,”
J. Struct. Biol.
,
122
, pp.
197
205
.
13.
Trombita´s
,
K.
,
Greaser
,
M.
,
Labeit
,
S.
,
Jim
,
J.-P.
,
Kellermayer
,
M.
,
Helmes
,
M.
, and
Granzier
,
H.
,
1998
, “
Titin Extensibility in situ: Entropic Elasticity of Permanently Folded and Permanently Unfolded Molecular Segments
,”
J. Cell Biol.
,
140
(
4
), pp.
853
859
.
14.
Oberhauser
,
A. F.
,
Marszalek
,
P. E.
,
Erickson
,
H. P.
, and
Fernandez
,
J. M.
,
1998
, “
The Molecular Elasticity of the Extracellular Matrix Protein Tenascin
,”
Nature (London)
,
393
, pp.
181
185
.
15.
Hegner
,
M.
,
Smith
,
S. B.
, and
Bustamente
,
C.
,
1999
, “
Polymerization and Mechanical Properties of Single RecA-DNA Filaments
,”
Proc. Natl. Acad. Sci. U.S.A.
,
96
, pp.
10109
10114
.
16.
Arruda
,
E. M.
, and
Boyce
,
M. C.
,
1993
, “
A Three-Dimensional Constitutive Model for the Large Stretch Behavior of Rubber Elastic Materials
,”
J. Mech. Phys. Solids
,
41
(
2
), pp.
389
412
.
17.
Spencer, A. J. M., 1984, “Constitutive Theory for Strongly Anisotropic Solids,” CISM Courses and Lectures III, (282), pp. 1–32.
18.
Bischoff
,
J. E.
,
Arruda
,
E. M.
, and
Grosh
,
K.
,
2001
, “
A New Constitutive Model for the Compressibility of Elastomers at Finite Deformations
,”
Rubber Chem. Technol.
,
74
(
4
), pp.
0541
0559
.
19.
Anand
,
L.
,
1996
, “
A Constitutive Model for Compressible Elastomeric Solids
,”
Comp. Mech.
,
18
, pp.
339
355
.
20.
Treloar
,
L. R. G.
, and
Riding
,
G.
,
1979
, “
A Non-Gaussian Theory for Rubber in Biaxial Strain—I: Mechanical Properties
,”
Proc. R. Soc. London, Ser. A
,
369
, pp.
261
280
.
21.
Bischoff, J. E., 2001, “Constitutive Modeling and Testing of Biological Soft Tissue,” Ph.D. thesis, University of Michigan.
22.
Wang
,
M. C.
, and
Guth
,
E.
,
1952
, “
Statistical Theory of Networks of Non-Gaussian Flexible Chains
,”
J. Chem. Phys.
,
20
(
7
), pp.
1144
1157
.
23.
Flory
,
P. J.
, and
Rehner
,
J.
, Jr.
,
1943
, “
Statistical Mechanics of Cross-Linked Polymer Networks
,”
J. Chem. Phys.
,
11
, pp.
512
520
.
24.
Malvern, L. E., 1969, Introduction to the Mechanics of a Continuous Medium, Prentice-Hall, Englewood Cliffs, NJ.
25.
Smith
,
G. F.
, and
Rivlin
,
R. S.
,
1958
, “
The Strain-Energy Function for Anisotropic Elastic Materials
,”
Trans. Am. Math. Soc.
,
88
(
1
), pp.
175
193
.
26.
Horowitz
,
A.
,
Lanir
,
Y.
,
Yin
,
F. C. P.
,
Perl
,
M.
,
Sheinman
,
I.
, and
Strumpf
,
R. K.
,
1988
, “
Structural Three-Dimensional Constitutive Law for the Passive Myocardium
,”
ASME J. Biomech. Eng.
,
110
, pp.
200
207
.
27.
Billiar
,
K. L.
, and
Sacks
,
M. S.
,
2000
, “
Biaxial Mechanical Properties of the Natural and Gluteraldehyde Treated Aortic Valve Cusp—Part II: A Structural Constitutive Model
,”
ASME J. Biomech. Eng.
,
122
, pp.
1
9
.
28.
Billiar
,
K. L.
, and
Sacks
,
M. S.
,
2000
, “
Biaxial Mechanical Properties of the Natural and Gluteraldehyde Treated Aortic Valve Cusp—Part I: Experimental Results
,”
ASME J. Biomech. Eng.
,
122
, pp.
23
30
.
29.
ABAQUS/Standard User’s Manual, Version 5.8, 1999, Hibbitt, Karlsson & Sorensen, Inc., Pawtucket, RI.
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