ROZWIĄZANIE RAMY METODĄ PRZEMIESZCZEŃ
WYZNACZANIE STOPNIA STATYCZNEJ NIEWYZNACZALNOŚCI
WYZNACZENIE LICZBY STOPNI SWOBODY OBROTU WĘZŁÓW
Uwzględniając, że φA1 = 0 , φ1A = φ13 = φ12 = φ1 , φ31 = φ32, φ21 = φ23 = φ2B = φ2, φB2 = 0, stwierdzam, że wszystkie kąty obrotu końców prętów określone są przez kąty obrotu 2 węzłów φ1 oraz φ2, więc
- liczba stopni swobody obrotu węzłów wynosi nφ=2
1.1.2 WYZNACZENIE LICZBY STOPNI SWOBODY PRZESUWU WĘZŁÓW
MODEL PRZEGUBOWY UKŁADU
w = 7; p = 7; r = 6 ∖ nnδ ≥ 2w − p − r = 2 • 7 − 7 − 6 = 1
Należy dodać co najmniej 1 więź.
Dodając więź IIδ przekształciłem model przegubowy układu w układ geometrycznie niezmienny. Zatem liczba stopni swobody przesuwu układu danego wynosi nδ=1.
Stopień geometrycznej niewyznaczalności wynosi : ng=nδ+nφ=1 + 2 = 3
UKŁAD PODSTAWOWY
1.2.1 OGÓLNA POSTAĆ UKŁADU RÓWNAŃ METODY PRZEMIESZCZEŃ
k11φ1 + k12φ2 + k1IIδII + k10 + k1(0T) = 0
k21φ1 + k22φ2 + k2IIδII + k20 + k2(0T) = 0
kII1φ1 + kII2φ2 + kII IIδII + kII0 + kII(0T) = 0
WYZNACZENIE WSPÓLCZYNNIKÓW UKŁADU RÓWNAŃ OD OBCIĄŻEŃ MECHANICZNYCH
1.3.1 ROZWIAZANIE UKŁADU PODSTAWOWEGO OD OBCIĄZENIA DANEGO (φ1 = φ2 = δII = 0)
$${M_{A1}}^{0} = - \frac{p \bullet L^{2}}{12} = - \frac{4 \bullet \frac{16}{25} \bullet 25}{12} = - 5.3333kNm$$
$${M_{1A}}^{0} = + \frac{p \bullet L^{2}}{12} = + \frac{4 \bullet \frac{16}{25} \bullet 5}{12} = + 5.3333kNm$$
M310 = 0
M130 = 0
M210 = 0
M120 = 0
M230 = 0
M320 = 0
$${M_{2B}}^{0} = - \frac{P \bullet a}{2} \bullet \left( 2 - \frac{a}{L} \right) = - \frac{24 \bullet 3}{2} \bullet \left( 2 - \frac{3}{4} \right) = - 45.00kNm$$
$${M_{B2}}^{0} = - \frac{P \bullet a^{2}}{2 \bullet L} = - \frac{24 \bullet 3^{2}}{2 \bullet 4} = - 27.00kNm$$
M20 = −20kNm
Siły równoważne mają wartości:
$$P_{1} = P_{2} = p \bullet \frac{L}{2} = \frac{4 \bullet \frac{16}{25} \bullet 5}{2} = 6.40kN$$
$$P_{3} = \frac{P}{L} = \frac{24}{4} = 6.00kN$$
$$P_{4} = \frac{a}{L} \bullet P = \frac{3}{4} \bullet 24 = 18.00kN$$
1.3.2 ROZWIAZANIE UKŁADU PODSTAWOWEGO OD φ1 = 1
(F = 0 φ2 = δII = 0)
W tym stanie obciążenia do wzorów transformacyjnych podstawiamy:
φ1A1 = φ121 = φ131 = φ1 = 1 pozostałe φij1 = 0 ψij1 = 0 Mij1 = 0
Momenty brzegowe wynoszą:
$${M_{A1}}^{1} = \frac{2EI}{5} \bullet 2 = 0.8\frac{\text{EI}}{m}\ $$
$${M_{1A}}^{1} = \frac{2EI}{5} \bullet 4 = 1.6\frac{\text{EI}}{m}\ $$
M311 = 0
$${M_{13}}^{1} = \frac{\text{EI}}{4} \bullet 3 = 0.75\frac{\text{EI}}{m}\ $$
$${M_{21}}^{1} = \frac{2EI}{4 \bullet \sqrt{2}} \bullet 2 = 0.7071\frac{\text{EI}}{m}$$
$${M_{12}}^{1} = \frac{2EI}{4 \bullet \sqrt{2}} \bullet 4 = 1.4142\frac{\text{EI}}{m}\ $$
M231 = 0
M321 = 0
M2B1 = 0
MB21 = 0
1.3.3 ROZWIAZANIE UKŁADU PODSTAWOWEGO OD φ2 = 1
(F = 0 φ1 = δII = 0)
W tym stanie obciążenia do wzorów transformacyjnych podstawiamy:
φ211 = φ2B1 = φ231 = φ2 = 1 pozostałe φij1 = 0 ψij1 = 0 Mij1 = 0
Momenty brzegowe wynoszą:
MA12 = 0
M1A2 = 0
M312 = 0
M132 = 0
$${M_{21}}^{2} = \frac{2EI}{4 \bullet \sqrt{2}} \bullet 4 = 1.4142\frac{\text{EI}}{m}$$
$${M_{12}}^{2} = \frac{2EI}{4 \bullet \sqrt{2}} \bullet 3 = 0.7071\frac{\text{EI}}{m}\ $$
$${M_{23}}^{2} = \frac{2EI}{4} \bullet 3 = 1.50\ \frac{\text{EI}}{m}$$
$${M_{32}}^{2} = \frac{2EI}{4} \bullet 0 = 0$$
$${M_{2B}}^{2} = \frac{\text{EI}}{4} \bullet 1 = 0.25\frac{\text{EI}}{m}$$
$${M_{B2}}^{2} = \frac{\text{EI}}{4} \bullet - 1 = - 0.25\frac{\text{EI}}{m}$$
1.3.4 ROZWIAZANIE UKŁADU PODSTAWOWEGO OD δII=1
(F = 0 φ1 = φ2 = 0)
W tym stanie obciążenia do wzorów transformacyjnych podstawiamy: φijII = 0
$$\frac{a}{x} = \frac{4}{3}\ \ \ \ \ \ \ \ \ \ \ \rightarrow \ \ \ \ \ \ \ \ \ a = \frac{4}{3}x$$
$$\frac{a}{1} = \text{tg}\left( \text{beta} \right) = \frac{4}{7}\text{\ \ \ \ } \rightarrow \text{\ \ \ \ \ \ }x = \frac{3}{7};\ \ a = \frac{4}{7} = c\ ;\ d = \frac{5}{4}a = \frac{5}{7};b = \sqrt{2} \bullet \frac{4}{7}$$
$${\psi_{A1}}^{\text{II}} = \frac{{_{A"1"}}^{\text{II}}}{L_{A1}} = \frac{d}{5} = 0.14285\frac{1}{m}\ $$
$${\psi_{13}}^{\text{II}} = \frac{{_{1"3"}}^{\text{II}}}{L_{13}} = \frac{c}{4} = 0.14285\frac{1}{m}$$
$${\psi_{23}}^{I} = \frac{{_{2"3"}}^{\text{II}}}{L_{13}} = \frac{a}{4} = 0.14285\frac{1}{m}$$
$${\psi_{12}}^{\text{II}} = \frac{{_{1"2"}}^{\text{II}}}{L_{12}} = \frac{d}{4\sqrt{2}} = 0.14285\frac{1}{m}$$
Momenty brzegowe wynoszą:
$${M_{A1}}^{\text{II}} = \frac{2EI}{5} \bullet \left( - 6 \right) \bullet 0.14285 = - 0.3429\frac{\text{EI}}{m^{2}}$$
$${M_{1A}}^{\text{II}} = \frac{2EI}{5} \bullet \left( - 6 \right) \bullet 0.14285 = - 0.3429\frac{\text{EI}}{m^{2}}\ $$
$${M_{31}}^{\text{II}} = \frac{\text{EI}}{4} \bullet \left( 0 \right) \bullet 0.14285 = 0\ $$
$${M_{13}}^{\text{II}} = \frac{\text{EI}}{4} \bullet \left( - 3 \right) \bullet 0.14285 = - 0.1071\frac{\text{EI}}{m^{2}}$$
$${M_{21}}^{\text{II}} = \frac{2EI}{4 \bullet \sqrt{2}} \bullet \left( - 6 \right) \bullet 0.14285 = - 0.3030\frac{\text{EI}}{m^{2}}$$
$${M_{12}}^{\text{II}} = \frac{2EI}{4 \bullet \sqrt{2}} \bullet \left( - 6 \right) \bullet 0.14285 = - 0.3030\frac{\text{EI}}{m^{2}}\ $$
$${M_{23}}^{\text{II}} = \frac{2EI}{4} \bullet \left( - 3 \right) \bullet 0.14285 = - 0.2143\ \frac{\text{EI}}{m^{2}}$$
$${M_{32}}^{\text{II}} = \frac{2EI}{4} \bullet 0 = 0$$
$${M_{2B}}^{\text{II}} = \frac{\text{EI}}{4} \bullet 0 = 0$$
$${M_{B2}}^{\text{II}} = \frac{\text{EI}}{4} \bullet 0 = 0$$
δs2II = cos45 • −1 = −0.7071
δP1II = 0
δP2II = 0.7143
δP3II = 1
δP4II = 1
1.3.5 OBLICZENIE WSPÓLCZYNNIKÓW UKŁADU RÓWNAŃ
$$k_{11} = \sum_{j}^{}{M_{1j}}^{1} + k_{1}^{\varphi} = 1.6\frac{\text{EI}}{m} + 0.75\frac{\text{EI}}{m} + 1.4142\frac{\text{EI}}{m} + 6\frac{\text{EI}}{m} = 9.7642\frac{\text{EI}}{m}$$
$$k_{12} = {M_{12}}^{2} = 0.7071\frac{\text{EI}}{m}$$
$$k_{1II} = \sum_{j}^{}{M_{1j}}^{\text{II}} = \left( - 0.3429\frac{\text{EI}}{m^{2}} \right) + \left( - 0.1071\frac{\text{EI}}{m^{2}} \right) + \left( - 0.3030\frac{\text{EI}}{m^{2}} \right) = - 0.7530\frac{\text{EI}}{m^{2}}$$
$$k_{10} = \sum_{j}^{}{M_{1j}}^{0} - {M_{1}}^{0} = 5.3333kNm$$
$$k_{21} = {M_{21}}^{1} = 0.7071\frac{\text{EI}}{m} = k_{12}$$
$$k_{22} = \sum_{j}^{}{M_{2j}}^{2} = 1.4142\frac{\text{EI}}{m} + 1.50\ \frac{\text{EI}}{m} + 0.25\frac{\text{EI}}{m} = 3.1642\frac{\text{EI}}{m}$$
$$k_{2II} = \sum_{j}^{}{M_{2j}}^{\text{II}} = \left( - 0.3030\frac{\text{EI}}{m^{2}} \right) + \left( - 0.2143\ \frac{\text{EI}}{m^{2}} \right) = - 0.5173\frac{\text{EI}}{m^{2}}$$
$$k_{20} = \sum_{j}^{}{M_{2j}}^{0} - {M_{2}}^{0} = - 45.00kNm - \left( - 20kNm \right) = - 25kNm$$
$$k_{II1} = - \sum_{\text{ij}}^{}{{(M_{\text{ij}}}^{1} + {M_{\text{ji}}}^{1}}) \bullet {\psi_{\text{ij}}}^{\text{II}} = = - \left\lbrack \left( 0.8\frac{\text{EI}}{m} + 1.6\frac{\text{EI}}{m} \right) \bullet 0.14285\frac{1}{m} + \left( 0.75\frac{\text{EI}}{m} + 0 \right) \bullet 0.14285\frac{1}{m} + \left( 0.7071\frac{\text{EI}}{m} + 1.4142\frac{\text{EI}}{m} \right) \bullet 0.14285\frac{1}{m} \right\rbrack = - 0.7530\frac{\text{EI}}{m^{2}} = k_{1II}$$
$$k_{II2} = - \sum_{\text{ij}}^{}{{(M_{\text{ij}}}^{2} + {M_{\text{ji}}}^{2}}) \bullet {\psi_{\text{ij}}}^{\text{II}} = = - \left\lbrack \left( 0.7071\frac{\text{EI}}{m} + 1.4142\frac{\text{EI}}{m} \right) \bullet 0.14285\frac{1}{m} + \left( 1.50\frac{\text{EI}}{m}\ + 0 \right) \bullet 0.14285\frac{1}{m} \right\rbrack = - 0.5173\frac{\text{EI}}{m^{2}} = k_{2II}$$
$$k_{\text{II\ II}} = - \sum_{\text{ij}}^{}{{(M_{\text{ij}}}^{\text{II}} + {M_{\text{ji}}}^{\text{II}}}) \bullet {\psi_{\text{ij}}}^{\text{II}} + {k_{2}}^{\delta} \bullet {\delta_{s2}}^{\text{II}} \bullet {\delta_{s2}}^{\text{II}} = - \left\lbrack \left( - 0.3429\frac{\text{EI}}{m^{2}} - 0.3429\frac{\text{EI}}{m^{2}} \right) \bullet 0.14285\frac{1}{m} + \left( - 0.1071\frac{\text{EI}}{m^{2}}\ + 0 \right) \bullet 0.14285\frac{1}{m} + \left( - 0.3030\frac{\text{EI}}{m^{2}}\ - 0.3030\frac{\text{EI}}{m^{2}} \right) \bullet 0.14285\frac{1}{m} + \left( - 0.2143\ \frac{\text{EI}}{m^{2}}\ + 0 \right) \bullet 0.14285\frac{1}{m} \right\rbrack + 4\frac{\text{EI}}{m^{3}} \bullet \left( - 0.7071 \right) \bullet \left( - 0.7071 \right) = 0.2305\frac{\text{EI}}{m^{3}} + 2\frac{\text{EI}}{m^{3}} = 2.2305\frac{\text{EI}}{m^{3}}$$
$$k_{II0} = - \sum_{\text{ij}}^{}{{(M_{\text{ij}}}^{0} + {M_{\text{ji}}}^{0}}) \bullet {\psi_{\text{ij}}}^{\text{II}} - \sum_{P}^{}{P_{P} \bullet}{\delta_{P}}^{\text{II}} = = - \left\lbrack \left( - 5.3333kNm + 5.3333kNm \right) \bullet 0.14285\frac{1}{m} \right\rbrack - \left\lbrack 6.40kN \bullet 0.7143 + 6.00kN \bullet 1 + 18.00kN \bullet 1 \right\rbrack = - 28.5715kN$$
WYZNACZENIE WSPÓLCZYNNIKÓW UKŁADU RÓWNAŃ OD OBCIĄŻEŃ NIEMECHANICZNYCH
1.4.1 WYZNACZENIE MOMENTÓW BRZEGOWYCH W UKŁADZIE PODSTAWOWYM OD ZMIAN TEMPERATURY PO WYSOKOŚCI PRZEKROJU PRĘTA
PRZYJETO PRZEKRÓJ I200 oraz 2I200 o EI=4387 kNm2
Momenty brzegowe wynoszą:
$${M_{A1}}^{\varphi T} = - \frac{2EI}{0.2} \bullet 1.2 \bullet 10^{- 5} \bullet ( - 16 - 16) = 0.00384\frac{\text{EI}}{m}$$
$${M_{1A}}^{\varphi T} = \frac{2EI}{0.2} \bullet 1.2 \bullet 10^{- 5} \bullet \left( - 16 - 16 \right) = - 0.00384\frac{\text{EI}}{m}\ $$
M31φT = 0
M13φT = 0
$${M_{21}}^{\varphi T} = \frac{2EI}{0.2} \bullet 1.2 \bullet 10^{- 5} \bullet ( - 20 - 20) = - 0.0048\frac{\text{EI}}{m}$$
$${M_{12}}^{\varphi T} = - \frac{2EI}{0.2} \bullet 1.2 \bullet 10^{- 5} \bullet ( - 20 - 20) = 0.0048\frac{\text{EI}}{m}\ $$
M23φT = 0
M32φT = 0
$${M_{2B}}^{\varphi T} = - \frac{\text{EI}}{0.2} \bullet 1.2 \bullet 10^{- 5} \bullet \left( 10 + 10 \right) = - 0.0012\frac{\text{EI}}{m}$$
$${M_{B2}}^{\varphi T} = \frac{\text{EI}}{0.2} \bullet 1.2 \bullet 10^{- 5} \bullet (10 + 10) = 0.0012\frac{\text{EI}}{m}$$
1.4.2 OBLICZENIE WSPÓLCZYNNIKÓW UKŁADU RÓWNAŃ
$$k_{1(OT)} = \sum_{j}^{}{M_{1j}}^{(OT)} = {M_{1A}}^{\varphi T} + {M_{13}}^{\varphi T} + {M_{12}}^{\varphi T} = - 0.00384\frac{\text{EI}}{m} + 0 + 0.0048\frac{\text{EI}}{m} = 9.6 \bullet 10^{- 4\ }\frac{\text{EI}}{m}\ $$
$$k_{2(OT)} = \sum_{j}^{}{M_{2j}}^{(OT)} = {M_{21}}^{\varphi T} + {M_{23}}^{\varphi T} + {M_{2B}}^{\varphi T} = - 0.0048\frac{\text{EI}}{m} + 0 - 0.0012\frac{\text{EI}}{m} = - 6 \bullet 10^{- 3\ }\frac{\text{EI}}{m}\ $$
$$k_{II(OT)} = - \sum_{\text{ij}}^{}{{(M_{\text{ij}}}^{(0T)} + {M_{\text{ji}}}^{(0T)}}) \bullet {\psi_{\text{ij}}}^{\text{II}} = 0$$
POSTAĆ SZCZEGÓŁOWA UKŁADU RÓWNAŃ OD OBCIĄŻEŃ MECHANICZNYCH
$$9.7642\frac{\text{EI}}{m}\varphi_{1} + 0.707\frac{\text{EI}}{m}1\varphi_{2} - 0.7530\frac{\text{EI}}{m^{2}}\delta_{\text{II}} + 5.3333kNm = 0$$
$$0.7071\frac{\text{EI}}{m}\varphi_{1} + 3.1642\frac{\text{EI}}{m}\varphi_{2} - 0.5173\frac{\text{EI}}{m^{2}}\delta_{\text{II}} - 25kNm = 0$$
$$- 0.7530\frac{\text{EI}}{m^{2}}\varphi_{1} - 0.5173\frac{\text{EI}}{m^{2}}\varphi_{2} + 2.2305\frac{\text{EI}}{m^{3}}\delta_{\text{II}} - 28.5715kNm = 0$$
ROZWIĄZANIE UKŁADU RÓWNAŃ OD OBCIĄŻEŃ MECHANICZNYCH
$$\varphi_{1} = - 0.1295\frac{\text{kN}m^{2}}{\text{EI}}$$
$$\varphi_{2} = 10.4116\frac{\text{kN}m^{2}}{\text{EI}}$$
$$\delta_{\text{II}} = 15.1804\frac{\text{kN}m^{3}}{\text{EI}}$$
1.5.2 MOMENTY BRZEGOWE I SIŁY W WIĘZIACH SPRĘŻYSTYCH
-0.1295 | f1 | 10.4116 | f2 | 15.1804 | dII | ||||
---|---|---|---|---|---|---|---|---|---|
M 1 | M 2 | M II | Mo | M rz | |||||
M A1 | 0.8000 | -0.1038 | 0.0000 | 0.0000 | -0.3429 | -5.2055 | -5.3333 | -10.6426 | |
M 1A | 1.6000 | -0.2075 | 0.0000 | 0.0000 | -0.3429 | -5.2055 | 5.3333 | -0.0797 | |
M 31 | 0.0000 | 0.0000 | 0.0000 | 0.0000 | 0.0000 | 0.0000 | 0.0000 | 0.0000 | |
M 13 | 0.7500 | -0.0973 | 0.0000 | 0.0000 | -0.1071 | -1.6259 | 0.0000 | -1.7231 | |
M 21 | 0.7071 | -0.0917 | 1.4142 | 14.7269 | -0.3030 | -4.5998 | 0.0000 | 10.0354 | |
M 12 | 1.4142 | -0.1834 | 0.7071 | 7.3635 | -0.3030 | -4.5998 | 0.0000 | 2.5803 | |
M 23 | 0.0000 | 0.0000 | 1.5000 | 15.6204 | -0.2143 | -3.2532 | 0.0000 | 12.3672 | |
M 32 | 0.0000 | 0.0000 | 0.0000 | 0.0000 | 0.0000 | 0.0000 | 0.0000 | 0.0000 | |
M 2B | 0.0000 | 0.0000 | 0.2500 | 2.6034 | 0.0000 | 0.0000 | -45.0000 | -42.3966 | |
M B2 | 0.0000 | 0.0000 | -0.2500 | -2.6034 | 0.0000 | 0.0000 | -27.0000 | -29.6034 |
$$S_{\varphi 1} = k^{\varphi} \bullet \varphi_{1} = 6\frac{\text{EI}}{m} \bullet \left( - 0.1295\frac{\text{kN}m^{2}}{\text{EI}} \right) = - 0.7770\ kNm$$
$$S_{\delta 2} = k^{\delta 2} \bullet \left( {\delta_{s2}}^{\text{II}} \bullet \delta_{\text{II}} \right) = 4\frac{\text{EI}}{m^{3}}\mathbf{\bullet}\left( - 0.7071 \bullet 15.1804\frac{\text{kN}m^{3}}{\text{EI}} \right) = - 42.9362\ kN$$
BRZEGOWE SIŁY TNĄCE I OSIOWE
Pręt A-1
$$\sum_{}^{}M_{A} \rightarrow \text{\ \ \ V}_{1A} = - \frac{\left( M_{A1} + M_{1A} \right)}{5m} - 4 \bullet \frac{4}{5} \bullet \frac{4}{5} \bullet \frac{5^{2}}{2} = - \frac{\left( - 10.6426 - 0.0797 \right)}{5m} - 2.56 \bullet \frac{5}{2} = - 4,2555\ kN$$
$$\sum_{}^{}M_{1} \rightarrow \text{\ \ \ V}_{A1} = - \frac{\left( M_{A1} + M_{1A} \right)}{5m} + 4 \bullet \frac{4}{5} \bullet \frac{4}{5} \bullet \frac{5^{2}}{2} = - \frac{\left( - 10.6426 - 0.0797 \right)}{5m} + 2.56 \bullet \frac{5}{2} = 8.5445\ kN$$
$$\sum_{}^{}X \rightarrow \ \ \ \ N_{1A} + 4 \bullet \frac{4}{5} \bullet \frac{3}{5} \bullet 5 - N_{A1} = 0\ \ \ \ \ N_{1A} = N_{A1} - 9.6$$
Pręt 1-3
$$\sum_{}^{}M_{1} \rightarrow \text{\ \ \ V}_{31} = - \frac{\left( M_{13} \right)}{4m} = - \frac{\left( - 1.7231 \right)}{4m} = 0.4308\ kN$$
$$\sum_{}^{}M_{3} \rightarrow \text{\ \ \ V}_{13} = - \frac{\left( M_{13} \right)}{4m} = - \frac{\left( - 1.7231 \right)}{4m} = 0.4308\ kN$$
$$\sum_{}^{}X \rightarrow \text{\ \ \ \ \ \ N}_{13}{= N}_{31}\text{\ \ \ \ }$$
Pręt 1-2
$$\sum_{}^{}M_{1} \rightarrow \text{\ \ \ V}_{21} = - \frac{\left( M_{12} + M_{21} \right)}{4 \bullet \sqrt{2}m} = - \frac{\left( 2.5803 + 10.0354 \right)}{4 \bullet \sqrt{2}m} = - 2.2302\ kN$$
$$\sum_{}^{}M_{2} \rightarrow \text{\ \ \ V}_{12} = - \frac{\left( M_{12} + M_{21} \right)}{4 \bullet \sqrt{2}m} = - \frac{\left( 2.5803 + 10.0354 \right)}{4 \bullet \sqrt{2}m} = - 2.2302\ kN$$
$$\sum_{}^{}X \rightarrow \text{\ \ \ \ \ \ N}_{12}{= N}_{21}\text{\ \ \ \ }$$
Pręt 2-3
$$\sum_{}^{}M_{2} \rightarrow \text{\ \ \ V}_{32} = - \frac{\left( M_{23} \right)}{4m} = - \frac{\left( 12.3672 \right)}{4m} = - 3.0918\ kN$$
$$\sum_{}^{}M_{3} \rightarrow \text{\ \ \ V}_{23} = - \frac{\left( M_{23} \right)}{4m} = - \frac{\left( 12.3672 \right)}{4m} = - 3.0918\ kN$$
$$\sum_{}^{}X \rightarrow \text{\ \ \ \ \ \ N}_{23}{= N}_{32}\text{\ \ \ \ }$$
Pręt 2-B
$$\sum_{}^{}Y \rightarrow \text{\ \ \ V}_{2B} = 24.00\ kN$$
$$\sum_{}^{}X \rightarrow \text{\ \ \ \ \ \ N}_{2B}{= N}_{B2}\text{\ \ \ \ }$$
WĘZEŁ 3
$$\sum_{}^{}M_{3} = 0 - \text{Spe}l\text{nione\ to}z\text{samo}s\text{ciowo}$$
$$\sum_{}^{}Y = 0\ \ \ \ \ \ N_{32} = N_{23} = V_{31} = 0.4308\ kN$$
$$\sum_{}^{}X = 0\ \ \ \ \ N_{31} = N_{13} = - V_{32} = 3.0918\ kN\ $$
WĘZEŁ 2
$$\sum_{}^{}M_{2} = - M_{21} - M_{23} - M_{2B} - 20 = - \lbrack 10.0354 + 12.3672 - 42.3966 + 20\rbrack = - 0.006 \approx 0 - \text{Spe}l\text{nione\ to}z\text{samo}s\text{ciowo}$$
$$\sum_{}^{}Y = N_{23} - V_{2B} + 0.7071V_{21} + 0.7071N_{21} - 0.7071S_{\delta 2} = 0$$
$$N_{21} = N_{12} = - \frac{1}{0.7071} \bullet \left\lbrack 0.4308 - 24 + 0.7071 \bullet \left( - 2.2302 \right) - 0.7071 \bullet \left( - 42.9362 \right) \right\rbrack = - 7,3738\ kN\ $$
$$\sum_{}^{}X = N_{2B} + + 0.7071S_{\delta 2} + V_{23} + 0.7071V_{21} - 0.7071N_{21} = 0$$
N2B = NB2 = −[0.7071 • (−42.9362) − 3.0918 + 0.7071 • (−2.2302) − 0.7071 • (−7.3738)]=30.1904 kN
WĘZEŁ 1
$$\sum_{}^{}M_{1} = - M_{1A} - M_{13} - M_{12} - S_{\varphi 1} = - ( - 0.0797) - ( - 1.7231) - 2.5803 - \left( - 0.7770 \right) = - 0.0005 \approx 0 - \text{Spe}l\text{nione\ to}z\text{samo}s\text{ciowo}$$
$$\sum_{}^{}Y = - \frac{4}{5} \bullet N_{1A} + \frac{3}{5} \bullet V_{1A} - 0.7071 \bullet V_{12} - 0.7071N_{12} - V_{13} = 0$$
N1A = 1.25 • [0.6•(−4,2555)−0.7071•(−2.2302)−0.7071•(−7,3738)−0.4308 ] = 4.7586 kN
N1A = NA1 − 9.6 NA1 = 9.6 + N1A = 9.6 + 4, 7586 = 14.3586 kN
WĘZEŁ PODPOROWY B
$$\sum_{}^{}M_{B} = M_{B} - M_{B2} = 0\ \ \ \ \ \ M_{B} = - 29.6034\ kNm$$
$$\sum_{}^{}Y = {0\ \ \ \ \ \ \ \ V}_{B} = 0$$
$$\sum_{}^{}X = N_{B} - N_{B2} = 0\ \ \ \ \ \ \ \ \ \ \ \ N_{B} = 30.1904\ kN\ $$
WĘZEŁ PODPOROWY A
$$\sum_{}^{}M_{A} = M_{A} - M_{A1} = 0\ \ \ \ \ M_{A} = - 10.6426kNm\ $$
$$\sum_{}^{}X = \frac{3}{5}N_{A1} + \frac{4}{5} \bullet V_{1A} + N_{A} = 0$$
NA = −[0.6•14.3586+0.8•8.5445] = −15.4508 kN
$$\sum_{}^{}Y = \frac{4}{5}N_{A1} - \frac{3}{5} \bullet V_{1A} + V_{A} = 0$$
VA = −0.8 • 14.3586 + 0.6 • 8.5445 = −6.3602 kN
MOMENTY ZGINAJĄCE
Pręt A-1
$$M\left( 2.5 \right) = M_{A} + \text{\ \ \ V}_{A1} \bullet 2.5 - 2.56 \bullet \frac{{2.5}^{2}}{2} = - 10.6426 + 8.5445 \bullet 2.5 - 8 = 2.7187\ kNm$$
V(2.5) = VA1 − 2.56 • 2.5 = 8.5445 − 2.56 • 2.5 = 2.1445 kN
SPRAWDZENIE
Dla X6 = 1
$$\sum_{}^{}M_{A} = 0$$
MA + x6 = 0
MA = −x6 = −1
$${_{6}}^{o} = \sum_{p}^{}{\int_{}^{}M_{6} \bullet \frac{M^{\text{rz}}}{\text{EI}}}dx + \frac{S_{\varphi 1}S_{6}}{k^{\varphi}} = 0$$
$$\frac{5}{6 \bullet 2EI} \bullet \left\lbrack \left( - 10.6426 \right) \bullet \left( - 1 \right) + 4 \bullet 2.7187 \bullet \left( - 1 \right) + 0.0797 \bullet \left( - 1 \right) \right\rbrack + \frac{- 1 \bullet - 0.7770}{6 \bullet 4387} = 9.4978 \bullet 10^{- 5} \bullet \left( - 0.3119 \right) + \frac{- 1 \bullet - 0.7770}{6 \bullet 4387} = - 1.05 \bullet 10^{- 7} \approx 0\ \ \ \ OK!\ $$
Dla X5 = 1
$${_{5}}^{o} = \sum_{p}^{}{\int_{}^{}M_{5} \bullet \frac{M^{\text{rz}}}{\text{EI}}}dx = 0$$
$$\frac{4 \bullet \sqrt{2}}{6 \bullet 2EI} \bullet \left\lbrack 2.5803 \bullet 1 + 4 \bullet ( - 3.5926) \bullet 0.5 + ( - 10.0354) \bullet 0 \right\rbrack + \frac{4}{6 \bullet EI} \bullet \left\lbrack \left( - 1.7231 \right) \bullet \left( - 1 \right) + 4 \bullet ( - 0.8616) \bullet \left( - 0.5 \right) + 0 \bullet 0 \right\rbrack = 1.0745 \bullet 10^{- 4} \bullet - 4.6049 + 1.5196 \bullet 10^{- 4} \bullet 3.4443 = 0.000028599\ \approx 0\ \ \ \ \ \ \ OK!\ $$
POSTAĆ SZCZEGÓŁOWA UKŁADU RÓWNAŃ OD OBCIĄŻEŃ NIEMECHANICZNYCH
$$9.7642\frac{\text{EI}}{m}\varphi_{1} + 0.707\frac{\text{EI}}{m}1\varphi_{2} - 0.7530\frac{\text{EI}}{m^{2}}\delta_{\text{II}} + 9.6 \bullet 10^{- 4\ }\frac{\text{EI}}{m} = 0$$
$$0.7071\frac{\text{EI}}{m}\varphi_{1} + 3.1642\frac{\text{EI}}{m}\varphi_{2} - 0.5173\frac{\text{EI}}{m^{2}}\delta_{\text{II}} - 6 \bullet 10^{- 3\ }\frac{\text{EI}}{m} = 0$$
$$- 0.7530\frac{\text{EI}}{m^{2}}\varphi_{1} - 0.5173\frac{\text{EI}}{m^{2}}\varphi_{2} + 2.2305\frac{\text{EI}}{m^{3}}\delta_{\text{II}} + 0 = 0$$
φ1 = −0.00021
φ2 = 0.002008
δII = 0.000394 m
1.10.2 MOMENTY BRZEGOWE I SIŁY W WIĘZIACH SPRĘŻYSTYCH
-0.00021 | f1 | 0.002008 | f2 | 0.000394 | dII | [EI/m] | [kNm] | |||
---|---|---|---|---|---|---|---|---|---|---|
M 1 | M 2 | M II | M(OT) | M rz | M rz | |||||
M A1 | 0.8000 | -0.0002 | 0 | 0.0000 | -0.3429 | -0.0001 | 0.00384 | 0.0035 | 15.3545 | |
M 1A | 1.6000 | -0.0003 | 0 | 0.0000 | -0.3429 | -0.0001 | -0.00384 | -0.0043 | -18.8641 | |
M 31 | 0.0000 | 0.0000 | 0 | 0.0000 | 0.0000 | 0.0000 | 0.00000 | 0.0000 | 0.0000 | |
M 13 | 0.7500 | -0.0002 | 0 | 0.0000 | -0.1071 | 0.0000 | 0.00000 | -0.0002 | -0.8774 | |
M 21 | 0.7071 | -0.0002 | 1.4142 | 0.0028 | -0.3030 | -0.0001 | -0.00480 | -0.0022 | -9.6514 | |
M 12 | 1.4142 | -0.0003 | 0.7071 | 0.0014 | -0.3030 | -0.0001 | 0.00480 | 0.0058 | 25.4446 | |
M 23 | 0.0000 | 0.0000 | 1.5 | 0.0030 | -0.2143 | -0.0001 | 0.00000 | 0.0029 | 12.7223 | |
M 32 | 0.0000 | 0.0000 | 0 | 0.0000 | 0.0000 | 0.0000 | 0.00000 | 0.0000 | 0.0000 | |
M 2B | 0.0000 | 0.0000 | 0.25 | 0.0005 | 0.0000 | 0.0000 | -0.00120 | -0.0007 | -3.0709 | |
M B2 | 0.0000 | 0.0000 | -0.25 | -0.0005 | 0.0000 | 0.0000 | 0.00120 | 0.0007 | 3.0709 |
$${S_{\varphi 1}}^{T} = k^{\varphi} \bullet \varphi_{1} = 6\frac{\text{EI}}{m} \bullet \left( - 0.00021 \right) = - 0.0013\frac{\text{EI}}{m} = - 5.7031\ kNm$$
$${S_{\delta 2}}^{T} = k^{\delta 2} \bullet \left( {\delta_{s2}}^{\text{II}} \bullet \delta_{\text{II}} \right) = 4\frac{\text{EI}}{m^{3}} \bullet \left( - 0.7071 \bullet 0.000394\ m \right) = - 0.001144\frac{\text{EI}}{m^{2}} = - 4.8889\ kN$$
Pręt A-1
$$\sum_{}^{}M_{A} \rightarrow \text{\ \ \ V}_{1A} = - \frac{\left( M_{A1} + M_{1A} \right)}{5m} = - \frac{\left( 15.3545 - 18.8641 \right)}{5m} = 0.7019\ kN$$
$$\sum_{}^{}M_{1} \rightarrow \text{\ \ \ V}_{A1} = - \frac{\left( M_{A1} + M_{1A} \right)}{5m} = - \frac{\left( 15.3545 - 18.8641 \right)}{5m} = 0.7019\ kN$$
$$\sum_{}^{}X \rightarrow \ \ \ \ N_{1A} - N_{A1} = 0\ \ \ \ \ N_{1A} = N_{A1}$$
Pręt 1-3
$$\sum_{}^{}M_{1} \rightarrow \text{\ \ \ V}_{31} = - \frac{\left( M_{13} \right)}{4m} = - \frac{\left( - 0.8774 \right)}{4m} = 0.2194\ kN$$
$$\sum_{}^{}M_{3} \rightarrow \text{\ \ \ V}_{13} = - \frac{\left( M_{13} \right)}{4m} = - \frac{\left( - 0.8774 \right)}{4m} = 0.2194\ kN$$
$$\sum_{}^{}X \rightarrow \text{\ \ \ \ \ \ N}_{13}{= N}_{31}\text{\ \ \ \ }$$
Pręt 1-2
$$\sum_{}^{}M_{1} \rightarrow \text{\ \ \ V}_{21} = - \frac{\left( M_{12} + M_{21} \right)}{4 \bullet \sqrt{2}m} = - \frac{\left( 25.4446 - 9.6514 \right)}{4 \bullet \sqrt{2}m} = - 2.7917\ kN$$
$$\sum_{}^{}M_{2} \rightarrow \text{\ \ \ V}_{12} = - \frac{\left( M_{12} + M_{21} \right)}{4 \bullet \sqrt{2}m} = - \frac{\left( 25.4446 - 9.6514 \right)}{4 \bullet \sqrt{2}m} = - 2.7917\ kN$$
$$\sum_{}^{}X \rightarrow \text{\ \ \ \ \ \ N}_{12}{= N}_{21}\text{\ \ \ \ }$$
Pręt 2-3
$$\sum_{}^{}M_{2} \rightarrow \text{\ \ \ V}_{32} = - \frac{\left( M_{23} \right)}{4m} = - \frac{\left( 12.7223 \right)}{4m} = - 3.1806\ kN$$
$$\sum_{}^{}M_{3} \rightarrow \text{\ \ \ V}_{23} = - \frac{\left( M_{23} \right)}{4m} = - \frac{\left( 12.7223 \right)}{4m} = - 3.1806\ kN$$
$$\sum_{}^{}X \rightarrow \text{\ \ \ \ \ \ N}_{23}{= N}_{32}\text{\ \ \ \ }$$
Pręt 2-B
$$\sum_{}^{}M_{B} \rightarrow \text{\ \ \ V}_{2B} = - \frac{\left( M_{B2} + M_{2B} \right)}{4m} = - \frac{\left( 3.0709 - 3.0709 \right)}{4m} = 0\ \ $$
$$\sum_{}^{}X \rightarrow \text{\ \ \ \ \ \ N}_{2B}{= N}_{B2}\text{\ \ \ \ }$$
WĘZEŁ 3
$$\sum_{}^{}M_{3} = 0 - \text{Spe}l\text{nione\ to}z\text{samo}s\text{ciowo}$$
$$\sum_{}^{}Y = 0\ \ \ \ \ \ N_{32} = N_{23} = V_{31} = 0.2194\ \ kN$$
$$\sum_{}^{}X = 0\ \ \ \ \ N_{31} = N_{13} = - V_{32} = 3.1806\ kN\ $$
WĘZEŁ 2
$$\sum_{}^{}M_{2} = - M_{21} - M_{23} - M_{2B} = - \lbrack - 9.6514 + 12.7223 - 3.0709\rbrack = 0 - \text{Spe}l\text{nione\ to}z\text{samo}s\text{ciowo}$$
$$\sum_{}^{}Y = N_{23} - V_{2B} + 0.7071V_{21} + 0.7071N_{21} - 0.7071{S_{\delta 2}}^{T} = 0$$
$$N_{21} = N_{12} = - \frac{1}{0.7071} \bullet \left\lbrack 0.7019 - 0 + 0.7071 \bullet \left( - 2.7917 \right) - 0.7071 \bullet \left( - 4.8889 \right) \right\rbrack = - 3.0898\ kN\ $$
$$\sum_{}^{}X = N_{2B} + + 0.7071S_{\delta 2} + V_{23} + 0.7071V_{21} - 0.7071N_{21} = 0$$
N2B = NB2 = −[0.7071 • (−4.8889) − 3.1806 + 0.7071 • (−2.7917) − 0.7071 • (−3.0898)]=6.4268 kN
WĘZEŁ 1
$$\sum_{}^{}M_{1} = - M_{1A} - M_{13} - M_{12} - {S_{\varphi 1}}^{T} = - ( - 18.8641) - ( - 0.8774) - 25.4446 - \left( - 5.7031 \right) = 0 - \text{Spe}l\text{nione\ to}z\text{samo}s\text{ciowo}$$
$$\sum_{}^{}Y = - \frac{4}{5} \bullet N_{1A} + \frac{3}{5} \bullet V_{1A} - 0.7071 \bullet V_{12} - 0.7071N_{12} - V_{13} = 0$$
N1A = 1.25 • [0.6•(0.7019)−0.7071•(−2.7917)−0.7071•(−3.0898)−0.2194 ] = 5.4507 kN
N1A = NA1 = 5.4507kN
WĘZEŁ PODPOROWY B
$$\sum_{}^{}M_{B} = M_{B} - M_{B2} = 0\ \ \ \ \ \ M_{B} = 3.0709\ kNm$$
$$\sum_{}^{}Y = {0\ \ \ \ \ \ \ \ V}_{B} = 0$$
$$\sum_{}^{}X = N_{B} - N_{B2} = 0\ \ \ \ \ \ \ \ \ \ \ \ N_{B} = 6.4268\ kN\ $$
WĘZEŁ PODPOROWY A
$$\sum_{}^{}M_{A} = M_{A} - M_{A1} = 0\ \ \ \ \ M_{A} = 15.3545\ kNm\ $$
$$\sum_{}^{}X = \frac{3}{5}N_{A1} + \frac{4}{5} \bullet V_{1A} + N_{A} = 0$$
NA = −[0.6•5.4507+0.8•0.7019] = −3.8319 kN
$$\sum_{}^{}Y = \frac{4}{5}N_{A1} - \frac{3}{5} \bullet V_{1A} + V_{A} = 0$$
VA = −0.8 • 5.4507 + 0.6 • 0.7019 = −3.9394 kN
MOMENTY ZGINAJĄCE
Pręt A-1
M(2.5) = MA + VA1 • 2.5 = 15.3545 + 0.7019 • 2.5 = 17.1093 kNm
SPRAWDZENIE
Dla X6 = 1
$$\sum_{}^{}M_{A} = 0$$
MA + x6 = 0
MA = −x6 = −1
$${_{6}}^{o} = \sum_{p}^{}{\int_{}^{}M_{6} \bullet \frac{M^{T}}{\text{EI}}}dx + \sum_{p}^{}{\int_{}^{}M_{6}d\varphi_{1}} + \sum_{S}^{}\frac{{S_{\varphi 1}}^{T}S_{6}}{k^{\varphi}} = 0$$
$$\frac{5}{6 \bullet 2EI} \bullet \left\lbrack \left( 15.3545 \right) \bullet \left( - 1 \right) + 4 \bullet 17.1093 \bullet \left( - 1 \right) + 18.8641 \bullet \left( - 1 \right) \right\rbrack + \left( - 5 \right) \bullet 1.2 \bullet 10^{- 5} \bullet \frac{- 32}{0.2} + \frac{- 1 \bullet - 5.7031}{6 \bullet \text{EI}} = - 9.75 \bullet 10^{- 3} + 9.6 \bullet 10^{- 3} + 2.1667 \bullet 10^{- 4} = 6.667 \bullet 10^{- 5} \approx 0\ \ \ \ OK!\ $$
Dla X5 = 1
$${_{5}}^{o} = \sum_{p}^{}{\int_{}^{}M_{6} \bullet \frac{M^{T}}{\text{EI}}}dx + \sum_{p}^{}{\int_{}^{}M_{6}d\varphi_{1}} = 0$$
$$\frac{4 \bullet \sqrt{2}}{6 \bullet 2EI} \bullet \left\lbrack - 9.6514 \bullet 1 + 4 \bullet ( - 17.5475) \bullet 0.5 + ( - 25.446) \bullet 0 \right\rbrack + \frac{4}{6 \bullet EI} \bullet \left\lbrack \left( - 0.8774 \right) \bullet \left( - 1 \right) + 4 \bullet ( - 0.4387) \bullet \left( - 0.5 \right) + 0 \bullet 0 \right\rbrack + \left( \frac{4\sqrt{2}}{2} \right) \bullet 1.2 \bullet 10^{- 5} \bullet \frac{- 40}{0.2} = 1.0745 \bullet 10^{- 4} \bullet - 44.7464 + 1.5196 \bullet 10^{- 4} \bullet 1.7548 - 6.7883 \bullet 10^{- 3} = - 0.0113 \approx 0\ \ \ \ \ \ OK!\ $$