Biomedical Engineering Reference
In-Depth Information
These equations are then solved for F and F 1 , thus
T and F 1
T
F
ð
X
;
t
Þ¼
1
þ½r o
u
ð
X
;
t
Þ
ð
x
;
t
Þ¼
1
½r
u
ð
x
;
t
Þ
:
(11.17)
The Lagrangian strain tensor E and the Eulerian strain tensor e are related to the
displacement gradients by substituting the two equations ( 11.17 ) into the two
equations ( 11.15 ), thus
T
T
E
¼
ð
1
=
2
Þf½r o
u
ð
X
;
t
Þ
þ½r o
u
ð
X
;
t
Þ þ ½r o
u
ð
X
;
t
Þ½r o
u
ð
X
;
t
g;
(11.18)
Þ
T
T
e ¼
ð
1
=
2
Þf½r uðx;
t
Þ
þ½ruðx;
t
Þ ½r uðx;
t
Þ½r uðx;
t
Þ
g:
(11.19)
The expanded component forms of ( 11.18 ) and ( 11.19 ) are given by
"
#
2
þ
2
2
E II ¼ @
u I
1
2
@
u I
@
u II
@
u III
@
x I þ
þ
;
@
@
x I
@
x I
x I
"
#
2
2
2
E II II ¼ @
u II
1
2
@
u I
@
u II
@
u III
x II þ
þ
þ
;
@
@
x II
@
x II
@
x II
"
#
;
2
2
2
E III III ¼ @
u III
1
2
@
u I
@
u II
@
u III
x III þ
þ
þ
@
@
x III
@
x III
@
x III
1
2
@
x II þ @
u I
u II
x I þ @
u I
x I @
u II
@
x I þ @
u II
@
@
u II
x II þ @
u III
@
@
u III
@
E III ¼
;
(11.20)
@
@
@
x I
@
x I
x II
@
x III þ @
u I
u III
@
x I þ @
u I
x I @
u III
@
x I þ @
u II
@
@
x III þ @
u II
u III
@
@
u III
1
2
E I III ¼
;
@
@
x I
@
x I
@
x III
1
2
@
x III þ @
u II
u III
@
x II þ @
u I
@
x III þ @
u II
u II
@
x III þ @
u II
u III
@
@
u III
E II III ¼
;
@
@
x II
@
@
x III
@
x II
@
x III
and
"
#
2
þ
2
þ
2
e 11 ¼ @
u 1
1
2
@
u 1
@
u 2
@
u 3
x 1
;
@
@
x 1
@
x 1
@
x 1
"
#
2
þ
2
þ
2
e 22 ¼ @
u 2
1
2
@
u 1
@
u 2
@
u 3
x 2
;
@
@
x 2
@
x 2
@
x 2
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