1.1. Wyznaczenie wartości reakcji w belce
Belka 1
1. S Py = 0
R1 + Rc – W1 + P = 0
R1 + Rc – 8 + 8 = 0
R1 = - Rc
2. S Px = 0
3. S M1 = 0
W1*2 – Rc*4 – P*8 = 0
8*2 – Rc*4 – 8*8 = 0
16 - Rc*4 -64 = 0
4*Rc = -48
Rc = -12 => R1 = 12
Belka 2
1. S Py = 0
RA + RB – W2 – R1 = 0
RA + RB – 24 -12 = 0
RA + RB = 36 => RA = 36 – RB = 16
2. S Px = 0
HA = 0
3. S MA = 0
6*RB + 12 – R1*9 – W2*1 = 0
6*RB + 12 – 108 – 24 = 0
6*RB = 120
RB = 20
1.2. Wyznaczenie wartości sił tnących i momentów zginających
Belka 1
1. 0 < x < 4
q(x) = x1/2
T(x) = -x/2*x + 12 = x2/2
TL(0) = 12
TP(4) = 4
M(x) = 12*x – x3/4
ML(0) = 0
MP(4) = 32
2. 0 < x1 < 4
T(x1) = -8
M(x1) = 8*x1
ML(0) = 0
MP(0) = 32
Belka 2
1. 0 < x < 3
q(x) = x2/6
T(x) = 12 + x2/6
TL(0) = 12
TP(3) = 13,5
M(x) = -12*x – x2/6*x/3 = -12x – x3/18
ML(0) = 0
MP(3) = -37,5
2. 3 < x1 < 6
T(x1) = -8 + x12/6
TL(3) = -6,5
TP(6) = -2
M(x1) = -12*x1 + 20(x1 – 3) – x13/18
ML(3) = -37,5
MP(6) = -24
3. 6 < x2 <9
T(x2) = -8 + x22/6
TL(6) = -2
TP(9) = 5,5
M(x2) = 8*x2 – x23/18 – 48
ML(6) = -12
MP(9) = -16,5
4. 9 < x3 < 12
T(x3) = -24 + x32/6
TL(9) = -10,5
TP(12) = 0
M(x3) = 24*x3 – 192 – x33/18
ML(9) = -16,5
MP(12) = 0
1.3. Sprawdzenie linii wpływu
RB = 24*1/6 + 12 * 5/6 + 8*3/4 = 20
2.1. Obliczenie wartości reakcji w ramie
Rama 1
S Px = 0
HA – ql = 0 => HA = ql
S Py = 0
RA + RB = 3/2ql => RA = 3/2ql – 5/4ql = 1/4ql
S MA = 0
ql2 + 9/8ql2 – 1/4ql2 – 3/2RB = 0
15/8ql – 3/2RB = 0
RB = 5/4ql
Rama 2
S M1L = 0
ql2 -2ql2 – H – 1/8ql2 +1/8ql2 = 0
H = -ql
2.2. Wyznaczenie wartości sił tnących, normalnych i momentów zginających
A – C 0 < y < 2l
T(y) = ql
N(y) = -1/4ql
M(y) = ql*y – 2ql*(y -1)
ML(0) = 2ql2
MP(2l) = 0
C – 1 0 < x < ½
T(x) = 1/4ql – qx
TL(0) = 1/4ql
TP(1/2) = -1/4ql
T(1/4) = 0
N(x) = - ql
M(x) = 1/4ql*x – 1/2qx2
ML(0) = 0
MP(1/2) = 0
1 – D 0 < x1 < 1
T(x1) = -5/4ql + qx1
TL(0) = -5/4ql
TP(1) = -1/4ql
N(x1) = -ql
M(x1) = 5/4ql2x1 – 3/4ql2 – 1/2qx12
ML(0) = - 3/4ql2
MP(1) = 0
E – D 0 < y1 < 2l
T(y1) = ql
N(y1) = -5/4ql
M(y1) = ql*(y1 – 1) + 1/4ql2
ML(0) = -3/4ql2
MP(2l) = 5/4ql2