X
Y
X
M
Y
Y
Y
M
M
M
X
Y
P
q
q
M
P=q*L P=q*L/2
L
0.5L 0.5L
L
2L/3 L/3
a
a
2a
P
A
B
P
A
B
Y
X
Y
A
A B
A=0
A+YB-P=0
A=0 => YB.L-P.L/2=0 => YB=P/2
A=0; YA=YB=P/2
a
Y2
Y1
b
A
MA1 quay
2
Y1.b-Y2.a=0
q
q
a b
q q
a b
X
Y Y
C
B C
A
B
C
A
B
C
AB
BC
QAB=q*a/2
q
a b
Y Y
B C
A
B
C
2a/3 a/3 b/2 b/2
QBC=q*b
X=0
C=0
Y=0 ta
YB+YC-(q.a/2+q.b)=0
MC=0 suy ra:
QBC.b.2+QAB.(b+a/3)-YB.b=0
=> q.b.b/2+q.a.(b+a/3)-YB.b=0
=> YB
XC=0
YB
YC
4060
20
2
2
2 4 2
4060
20
2 4 2
Y
Y
B
A
XA-20.2=0XA=40
A
X
20.2.1+40 -YB.4-60=0
YB=5
YA-YB=0YA=5
C
A
B
D
C
E
P=20
q=10
q=10
F
B
E
P=20
q=10
F
X
Y
B
B
Y
E
10.4.2+20.4-YE.2=0 suy ra YE=80
B, YB
XB=0
YB+10.4+20-YE=0 YB=20
A
B
D
q=10
thanh CD
RCD
Y
X
XB=0
YB=20
RCD.
CD
A
A
B
B
YB
XB
Y'B
X'B
XB=X'B
YB=Y'B
XB X'BB Y'B
B
P
RCD.Cos60.4+YB.6-10.6.3=0 suy ra RCD=30
X
C