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area A , bounded by the lines x
=
0 ,x
=
a, y
=
0, and y
=
b . Begin with the final integral
on the right-hand side of Eq. (1.117). Introduce D T
of Eq. (1.50a) and set D T
D T
σ =
σ x
σ y
τ xy
dA
[ u x u y ] x
0
y
u T D T
σ
σ dA
=
0
y
x
A
A
b
a
a
b
a
b
=
u x σ x,x dx dy
+
u x τ xy, y dy dx
+
u y σ y, y dy dx
0
0
0
0
0
0
b
a
+
u y τ xy,x dx dy
0
0
b
u x σ x
a
u x,x σ x dx dy
a
u x τ xy
b
u x, y τ xy dy dx
a
0
b
0
=
+
0
0
0
0
a
u y σ y
b
u y, y σ y dy dx
b
u y τ xy
a
u y, x τ xy dx dy
b
0
a
0
+
+
0
0
0
0
σ x
σ y
τ xy
σ x
σ y
τ xy
[ u x u y ] 100
001
[ u x u y ] 001
010
b
a
a
b
=
dy
+
dx
0
0
0
0
b
a
b
a
u x,x σ x dx dy
u y, x τ xy dx dy
0
0
0
0
a
b
a
b
u x, y τ xy dy dx
u y, y σ y dy dx
0
0
0
0
σ x
σ y
τ xy
ds
σ x
σ y
τ xy
dA
[ u x u y ] a x
[ u x u y ] x
0
a y
0
y
=
0
a y
a x
0
y
x
S
A
u T A T σ ds
u T u D T σ dA
=
(1.118)
S
A
where a x and a y represent the direction cosines of the unit normal to s and x
are
partial derivatives of the preceding quantities ( u x and u y as appropriate). Thus, D u and
D T
σ
and y
are adjoints in the sense of Eq. (1.117) for the case of two-dimensional elasticity.
The situation is similar for the case of beams with shear deformation. For a beam
element from x
=
a to x
=
b ,
N
V
M
dx
b
b
d x
00
u T D s s dx
=
[ u 0
]
0
d x
0
a
a
0
1
d x
b
[ u 0 N + w
V + θ(
M
=
V
)
] dx
a
b
a (
b
a
u 0 N
+ w V
+ θ M
= (
u 0 N
+ w
V
+ θ
M
) |
+ θ
V
)
dx
N
V
M
b +
N
V
M
a
100
010
001
100
0
=
[ u 0
]
[ u 0
]
10
00
1
N
V
M
dx
b
x d 00
0 x d 0
01 x d
[ u 0
]
a
b
u T A T s
b
a
u T u D T s dx
=
|
a
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