MODOS DE VIBRACIΓN AnΓ‘lisis del edificio en Y. Datos: πΈπ = 200 ππ/ππ2 Calcular: ο· ο· ο· ο· Matriz de masa [π] =? Matriz de
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MODOS DE VIBRACIΓN AnΓ‘lisis del edificio en Y. Datos: πΈπ = 200 ππ/ππ2 Calcular: ο· ο· ο· ο·
Matriz de masa [π] =? Matriz de rigidez [π] =? Matriz de frecuencia [π€ 2 ] =? Grafica de los modos normalizados [Ξ¦π ] =?
2
SOLUCIΓN:
Inercias del pΓ³rtico 1x-4x π β ππ π°= ππ INERCIA 1 πΌ1 =
40 β (40)3 = 213333.33 ππ4 12
INERCIA 2 πΌ2 =
30 β (40)3 = 160000 ππ4 12
INERCIA 3 πΌ3 =
30 β (30)3 = 67500 ππ4 12
Rigideces del edificio πΎ= πΎ1 =
12πΈπΌ π»3
12 β (200 ππ/ππ2 )(213333.33ππ4 ) (400 ππ)3 πΎ1 = 7.999 ππ/ππ
πΎ2 = πΎ2 =
12 πΈπΌ π»3
12 β (200 ππ/ππ2 )(160000ππ4 ) (300ππ)3 πΎ2 = 14.22 ππ /ππ K2=k3=k4
πΎ= πΎ5 =
12πΈπΌ π»3
12 β (200 ππ/ππ2 )(67500 ππ4 ) (300 ππ)3 πΎ5 = 6.00 ππ/ππ K5=K6
Resultados SENTIDO X
Columnas
PΓ³rtico 1X β 4X
PΓ³rtico 2X-3X
TOTAL
K1 K2 K3 K4 K5 K6
63,992 113,776 113,776 113.776 36.00 24.00
156.248 296.296 296.296 113.776 85.36 56.888
220.24 410.072 410.072 227.552 121.36 80.88
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DEFORMADA
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MATRIZ DE K (RIGIDEZ) π1 + π2 βπ2 0 βπ2 π2 + π3 βπ3 0 βπ3 π3 + π4 [π] = 0 0 βπ4 0 0 0 [ 0 0 0
8π1 + 8π2 β8π2 0 β8π2 8π2 + 8π3 β8π3 0 β8π3 8π3 + 8π4 [π] = 0 0 β8π4 0 0 0 [ 0 0 0
0 0 0 0 0 0 βπ4 0 0 π4 + π5 βπ5 0 π5 + π6 βπ6 βπ5 βπ6 π6 ] 0
0 0 0 0 0 0 β8π4 0 0 8π4 + 8π5 β6π5 0 6π5 + 4π6 β4π6 β6π5 β4π6 4π6 ] 0
K1 (MATRIZ DE RIGIDEZ) 177.768 β113.776 0 0 0 0 β113.776 227.552 β113.776 0 0 0 0 β113.776 β113.776 0 0 227.552 [π] = ππ/ππ2 0 0 0 β113.776 149.776 β36 0 0 β36 60 β24 0 [ 0 0 0 0 β24 24 ]
Inercia del pΓ³rtico 2x-3x INERCIA 1 50 β (50)3 πΌ1 = = 520833.33 ππ4 12 INERCIA 2 40 β (50)3 πΌ2 = = 416666.67 ππ4 12 INERCIA 3 πΌ3 =
30 β (40)3 = 160000 ππ4 12
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Rigideces del edificio πΎ= πΎ1 =
12πΈπΌ π»3
12 β (200 ππ/ππ2 )(520833.33ππ4 ) (400 ππ)3 πΎ1 = 19.531 ππ/ππ
πΎ2 = πΎ2 =
12 πΈπΌ π»3
12 β (200 ππ/ππ2 )(416666.67ππ4 ) (300ππ)3 πΎ2 = 37.037 ππ /ππ K2=K3
πΎ= πΎ4 =
12πΈπΌ π»3
12 β (200 ππ/ππ2 )(160000 ππ4 ) (300 ππ)3 πΎ4 = 14.222 ππ/ππ K4=K5=K6
8π1 + 8π2 β8π2 0 β8π2 8π2 + 8π3 β8π3 0 β8π3 8π3 + 8π4 [π] = 0 0 β8π4 0 0 0 [ 0 0 0
0 0 0 0 0 0 β8π4 0 0 8π4 + 8π5 β6π5 0 6π5 + 4π6 β4π6 β6π5 β4π6 4π6 ] 0
K2 (MATRIZ DE RIGIDEZ) 0 0 0 452.544 β296.296 0 0 0 0 β296.296 592.592 β296.296 β113.776 0 0 0 β296.296 410.072 [π] = ππ/ππ 0 0 0 β113.776 199.108 β85.332 0 0 0 β85.332 142.220 β56.88 [ β56.888 56.888 ] 0 0 0 0
K1+K2 (SUMA DE MATRIZ DE RIGIDEZ)
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0 0 0 630.312 β410.072 0 0 0 0 β410.072 820.144 β410.072 0 β410.072 637.624 0 0 β227.552 [π] = ππ/ππ 0 0 β227.552 348.884 β121.332 0 0 0 0 β121.332 202.220 β80.888 [ 0 0 0 β80.888 80.888 ] 0
Matriz de masa π1,2,3,4 =
π 270 ππ = = 0.275 ππ π β2 /ππ π 980 ππ/π 2 π1 = π2 = π3 = π4
π5 =
π 165 ππ = = 0.168 ππ π β2 /ππ π 980 ππ/π 2
π6 =
π 75 ππ = = 0.076 ππ π β2 /ππ π 980 ππ/π 2
π1 0 0 π2 0 [π] = 0 0 0 0 0 [ 0 0
0 0 0 0 0 0 0 π3 0 0 π4 0 0 0 π5 0 0 0
0 0 0 0 0 π6]
0.275 0 0 0 0 0 0 0.275 0 0 0 0 0 0 0 0 0 0.275 [π] = πππ β2 /ππ 0.275 0 0 0 0 0 0 0.168 0 0 0 0 [ 0 0 0 0.076] 0 0
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MATRIZ DE FRECUENCIA DEL SISTEMA 0 0 0 85.20 0 0 0 0 0 0 457.30 0 0 0 0 0 0 1163.80 [π€ 2 ] = 0 1966.80 0 0 0 0 0 0 0 0 0 2632.50 [ 0 0 4824.10] 0 0 0
FRECUENCIA (W)= W1= W2= W3= W4= W5= W6=
9.230 rad 21.385 rad 34.115 rad 44.349 rad 51.308 rad 69.456 rad
οΆ Periodo de LiberaciΓ³n: π1 =
2π 2 β 3.1416 = = 0.681 π π π€1 9.230 π πβ1
π2 =
2π 2 β 3.1416 = = 0.294 π π π€2 21.385 π πβ1
π3 =
2π 2 β 3.1416 = = 0.184 π π π€1 34.115 π πβ1
π4 =
2π 2 β 3.1416 = = 0.142 π π π€1 44.349 π πβ1
π5 =
2π 2 β 3.1416 = = 0.122 π π π€1 51.308 π πβ1
π6 =
2π 2 β 3.1416 = = 0.090 π π π€1 69.456 π πβ1
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οΆ Resultados
Matriz normalizada 1.0957 βπ. 8397 βπ. 4226 0.6915 β0.8449 0.6001 1.4258 β0.6255 0.8509 β0.6392 0.1309 β0.5202 0.7493 β0.9213 β0.5109 β1.1544 β0.7925 0.0653 [Ξ¦π ] = 0.2201 β1.01220 0.1522 1.2431 β0.4531 0.8888 β1.2282 β1.1254 0.1730 1.6752 β0.5825 β0.0456 [ β1.3351 β1.9730 β1.8503 β1.9755 0.3953 0.0129 ]
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