Thus, the stress field given does not meet requirements for solution... Thus, Solution is not valid... On the basis of Eq... Stress field along the edges of the plate, as determined from
Trang 1CHAPTER 3
SOLUTION (3.1)
( a ) We obtain
pxy
4 4
4 4
4
=
=
!
= """#
"
#
"
"
#
"
Thus, #4" = ! 12 pxy + 2 ( 6 pxy ) = 0
and the given stress field represents a possible solution
2
!
=
"
#
"
Integrating twice
) ( )
1 10 6
5 3 3
y f x y f y px y
=
"
The above is substituted into "4! = 0 to obtain
0
4 4 4
4dy f(y) +d dy f (y) =
This is possible only if
0
4 4
4dy f(y) = d dy f (y) =
d
We find then
7 6
2 5
3 4
11 10
2 9
3 8
Therefore,
11 10
2 9
3 8 7 6
2 5
3 4 10
c y c y c y c x c y c y c y c y px y
=
"
( c ) Edge y=0:
" "
!
!" = " =
a
a
a y
Edge y=b:
4
3
!
t c b c a t b
1 5
2
+ +
!
!
=
a
!
SOLUTION (3.2)
Edge x ± = a :
0 :
2 1 2 1 2 2 2
!
xy
"
0 :
2 1 2 1 2 2 2
!
xy
"
1
(CONT.)
Click here to Purchase full Solution Manual at http://solutionmanuals.info
Solution Manual for Advanced Mechanics of Materials and Applied Elasticity
5th Edition by Ugural and Fenster
Trang 23.2 (CONT.)
3
2 2
3
Edge x = a :
0 2
:
= pa y c ay c y
x
"
or
3
2 2 pa
c =
SOLUTION (3.3)
( a ) Equations (3.6) become
0
=
!
!
x y
"
"
#
Substituting the given stresses, we have
0
2 3
2y ! c y =
c
Thus
=
2 2
xy
#
Assume c1 > 0 and c2 > 0
SOLUTION (3.4)
Boundary conditions, Eq (3.6):
0
= +!! !! !!
!
!
y x y
"
#
#
"
or ( 2 ab ! 2 ab ) x = 0 ( ! 2 ab + 2 ab ) y = 0
are fulfilled
However, equation of compatibility:
0 ) )(
2 2 2
= + + !!
!
!
y x y
x " " or 4 ! ab 0 is not satisfied
Thus, the stress field given does not meet requirements for solution
SOLUTION (3.5)
It is readily shown that
0 1
4! =
" is satisfied
0 2
4! =
" is satisfied
(CONT.)
y
) ( 2 2
22 b y
c
xy = !
"
y a c c
x = ( 1+ 2 )
!
x
) ( 2 2
22 b y
c
xy = !
"
y c
x = 1
!
b
b
a
Trang 33.5 (CONT.)
We have
b a
y
x = ""# = = ""# = = !""2#"1 = !
2 2 2
2
, 2 ,
%
Thus, stresses are uniform over the body
Similarly, for!2:
cy bx by
ax dy
x = 2 + 6 # = 6 + 2 " = ! 2 ! 2
#
Thus, stresses vary linearly with respect to x and y over the body
SOLUTION (3.6)
Note: Since !z = 0and!y = 0, we have plane stress in xy plane and plane strain
in xz plane, respectively
Equations of compatibility and equilibrium are satisfied by
0
!
x " " c "
"
0
=
=
= yz xz
xy ! !
!
We have
0
=
y
Stress-strain relations become
E y E
) ( )
( , " !"
!"
"
#
0 ,
) (
=
=
=
z x y " " "
# % $ $
Substituting Eqs (a,b) into Eqs (c), and solving
E z
y "!0 # "(1")!0
0
0
2 ) 1
!
y E
" #$
Then, Eqs (2.3) yield, after integrating:
0
0
2 ) 1
!
u #E" x
E z
w " + ( 1 " ) ! 0
=
SOLUTION (3.7)
Equations of equilibrium,
0 2
2 ,
= +!!
!
!#x x "y xy axy axy
0 ,
= + ""
"
" $y xy #x y ay ay
are satisfied Equation (3.12) gives
0 4 ) )(
2 2 2
!
"
= + + ##
#
Compatibility is violated; solution is not valid
(a)
(c)
Trang 4SOLUTION (3.8)
We have
ay
x y
xy y
2 2
2
=
!
=
= "" " "
"
Equation of compatibility, Eq (3.8) is satisfied Stresses are
) (
)
1
y x E
) (
)
1
x y E
2 ) 1 (
xy
xy " !
Equations (3.6) become
0 )
2 3
1!aE2 x + xy + aE+ xy =
"
" "
0
2 1
2
1!aE2 y + !aE2 x =
"
"
These cannot be true for all values of x and y Thus, Solution is not valid
SOLUTION (3.9)
ax
y x
u
x = = ! 2 = "" = 2
"
#
0 2
!
= +
= ""
"
" x v cy cy
y
u xy
#
Thus
xy xy
y x E
% = 1( + ) = 0 =
Ecx
x y
E
y =1! 2( # + "# ) = 2
$ "
Note that this is a state of pure bending
SOLUTION (3.10)
2
px pxy xy
y y
x = ""# = % = $ = !
%
Note that "4! = 0 is satisfied
( b )
( c ) Edge x = 0 : Vy = Px = 0
(CONT.)
y
x
pbx
y = 6
!
2
3px
xy =
!
0
=
x
!
2
3pa
xy =
!
0
=
y
! !xy = 3px2
0
=
x
!
0
=
xy
a
2a 2b
O
y
x
2Eac
2Eac
Trang 53.10 (CONT.)
!
=
!
=
0#
Edge y = b : Vx = pa3t !
!
=
SOLUTION (3.11)
( a ) We have #4" ! 0 is not satisfied
2 2 2
2 2
2 2 2
2 ) 4 ( )
xy a
xy x p x a
py x
%
( b )
6 2
0
Edge x = a :
!
=
0#
!
=
0#
Edge y = a :
!
=
0#
!
=
SOLUTION (3.12)
( a ) We have "4! = 0 is satisfied The stresses are
0 )
12 6
2 3
2 2
=
=
!
!
=
"
#
"
x y b
px y
$
) (
3
y x
xy = !"""# = !
$
(CONT.)
y
p
y =
!
0
=
x
!
2 2
2a
py
xy = !
"
) 4 1 (
p
xy = +
!
2p
) 4 (
2
2py a a y
!
) 1 ( a y
x = p +
!
0 ,
= xy
"
a a
Trang 63.12 (CONT.)
( b )
SOLUTION (3.13)
We have
2 2 2
[tan 1
y x y Py x y
x
xy x y P
"#
]
2 2 2 2 2 2
2
) ( 2 ) (
y x x y x y x y
x x
P
! + +
"
#
" = !$ +
The stresses are thus,
2 2 3 2
2
) (
2
y
x x
P y
x = !!" = # $ +
%
2 2 2 2 2
2
) (
2
y x xy P x
y = !!" = # $ +
%
2 2 2 2
) (
2
y x y x P y x
xy = #!!!" = # $ +
%
SOLUTION (3.14)
Various derivatives of ! are:
0 ),
2 2
3 2 0
"#
"
x h
y h
y
x $ y
) 1
( ,
2 0
2 2
2
4 h y h y y
x y
x = ""# = ! !
"
"
#
) 2
2
0 2
y = ! x ! + L +
"
#
" $
0 ,
4 4
4
=
= !!"
!
"
!
y x
It is clear that Eqs (a) satisfy Eq (3.17) On the basis of Eq (a) and (3.16), we obtain
(CONT.) (a)
y
) 12 6 (
b
pa
"
xy
!
x
xy
!
b
a
L
L
P !
2
P
x
!
xy
!
Trang 73.14 (CONT.)
0 ),
2 2
" #
) 1
2
4 h y h y
xy = !" ! !
"
From Eqs (b), we determine
Edge y = h : "y = 0 !xy = !0
Edge y = ! h : #y = 0 "xy = 0
2
4 h y h y xy
x L
x = # = " = !" ! !
It is observed from the above that boundary conditions are satisfied at y ± = h,
but not at x = L
SOLUTION (3.15)
( a ) For #4" = 0 , e = ! 5 dand a, b, c are arbitrary
( b ) The stresses:
) 3 2 ( 10
2 2
y x y d cy y
x = ""# = + !
3 10 2
2
2 2
dy by
a
x
y = ""# = + !
2 30 2
2
dxy bx
y x
xy = !"""# = ! !
Boundary conditions:
0
=
!
y p "
Equations (3), (4), and (5) give
p dh a
dh
0 0
h
h xy
h
h x
h
Equations (2), (4), and (7) yield
2
2dh
Similarly
0
Solution of Eqs (6), (8), and (9) results in
3
80 40
163
The stresses are therefore
) 3 2
8 20
3
h
p h
py
"
3 3
8 8
3
2 py h py h
p
y = ! ! !
"
) 1
2
8
3
h
y h
px
xy = !
"
(b)
Trang 8SOLUTION (3.16)
We obtain
2 2 2 2
a y x p y
x = ""# = !
$
2 2 2 2
a
py x
y = !!" =
2
a
pxy y
x
xy = !"""# = !
$
Taking higher derivatives of !, it is seen that Eq (3.17) is not satisfied
Stress field along the edges of the plate, as determined from Eqs (a),
is sketched bellow
SOLUTION (3.17)
The first of Eqs (3.6) with Fx = 0
I
pxy
y xy =
!
!
Integrating,
) ( 1 2
2
x f I
pxy
xy = +
The boundary condition,
) ( 0
)
x f I
pxh h
y
xy = = = +
!
) ( 2 2
2px I h y
xy = ! !
Clearly, ( "xy)y !h = 0 is satisfied by Eq (b)
Then, the second of Eqs (3.6) with Fy = 0 results in
I y h p
y y (2 )
2
2 !
"
"
=
#
Integrating,
) ( )
2
2
x f h
I
p
Boundary condition, with t = 3 I 2 h2 ,
(CONT.)
p
y =
!
0
=
xy
!
2 2
2 a y
x = p
!
a x
xy = 2 p
!
2p
a y
xy = 2 p
!
) 2 1
2
a
y
x = p !
"
0 ,
= xy
"
a
a
p
y
2
a