Multi Degree of Freedom (MDOF)

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m3 m2 m1 1 MULTI DEGREE OF FREEDOM (MDOF) TUGAS 5 Persamaan Umum SDOF m ¨ Χ ( t )+ C ¨ Χ ( t )+ Kx ( t )=F ( t )=−m ¨ Χg Persamaan Umum MDOF [ M 1 M 2 M 3 ] { ¨ Χ ( t ) ¨ Χ ( t ) ¨ Χ ( t ) } + [ C 1 C 2 C 3 ] { ¨ Χ ( t ) ¨ Χ ( t ) ¨ Χ( t ) } + [ ( K 1 +K 2 ) K 2 0 K 2 K 2 +K 3 K 3 0 K 3 K 3 ] { X 1 ( t ) X 2 ( t ) X 3 ( t ) } =− [ M 1 M 2 M 3 ] { ¨ Χg 1 ¨ Χg 2 ¨ Χg 3 } = { X 1 ( t ) X 2 ( t ) X 3 ( t ) } Contoh Kasus 2

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Sekedar tugas kuliah Multi Degree Of Freedom (MDOF)

Transcript of Multi Degree of Freedom (MDOF)

Page 1: Multi Degree of Freedom (MDOF)

K

1

MULTI DEGREE OF FREEDOM (MDOF)

TUGAS 5

Persamaan Umum SDOF

m Χ̈ ( t )+C Χ̈ ( t )+Kx ( t )=F ( t )=−m Χ̈ gPersamaan Umum MDOF

[M 1 M 2M 3 ]{Χ̈ ( t )

Χ̈ ( t )Χ̈ ( t )}+[C 1 C2

C3 ]{Χ̈ ( t )Χ̈ ( t )Χ̈ ( t )}+[(K1+K 2 ) −K2 0

−K2 K2+K 3 −K 30 −K3 K 3 ]{X 1( t )X 2( t )

X3 ( t )}=−[M 1 M 2

M 3 ]{Χ̈ g1Χ̈ g2Χ̈ g3 }={X 1( t )X 2( t )

X 3( t )}Contoh Kasus

m1

m2

m3

K

2

K3

Page 2: Multi Degree of Freedom (MDOF)

M1 = 1

M2 = 2

M3 = 3

K1 = 1500.00

K2 = 1000.00

K3 = 500.00

3 0 0[M] = 0 2 0

0 0 1

2500.00 -1000.00 0[K] = -1000.00 1500.00 -500.00

0 -500.00 500.00

|[K ]−ω2 [M ]|=0

|[2500 −1000 0−1000 1500 −5000 −500 500 ]−ω2 [3 0 0

0 2 00 0 1 ]|=0

500|[ 5 −2 0−2 3 −10 −1 1 ]−ω2[3 0 0

0 2 00 0 1 ]|=0

500|[(5−3ω2 ) −2 0

−2 (3−2ω2 ) −10 −1 (1−ω2 ) ]|=0

Di asumsikan

λ= ω2

500

Page 3: Multi Degree of Freedom (MDOF)

|[(5−3 λ ) −2 0−2 (3−2 λ ) −10 −1 (1− λ) ]|=0

(5−3 λ )[3−2λ −1−1 (1−λ ) ]+2 [−2 −1

0 (1−λ ) ]+0=(5−3 λ ) {(3−2λ )(1−λ )−1 }+2 [−2(1−λ )]=

(5−3 λ ) {(3−2λ )(1−λ )−1 }−4+4 λ=

(5−3 λ )(3−3 λ−2λ+2 λ2−1)−4+4 λ=

{5(3−3 λ−2 λ+2 λ2−1 )−3 λ(3−3 λ−2 λ+2 λ2−1)}−4+4 λ=15−15 λ−10 λ+10 λ2−5−9 λ+9 λ2+6 λ2−6 λ3+3 λ−4+4 λ=−6 λ3+10 λ2+9 λ2+6 λ2−15 λ−10 λ−9 λ+3 λ+4 λ+15−5−4=−6 λ3+25 λ2−34 λ+3 λ+4 λ+6=

−6 λ3+25 λ2−34 λ+3 λ+4 λ+6=

−6 λ3+25 λ2−27 λ+6=

(−6 x3)+25 x2−27 x+6=0

Di dapat: (diurutkan dari nilai yang terkecil)

X1= λ1= 0,299

X2= λ2= 1,304

X3= λ3= 2,563

Page 4: Multi Degree of Freedom (MDOF)

Masukkan nilai –nilai di atas ke dalam persamaan

|[ [K ]−ω2 [M ] ]|{φ}=0

Untuk λ1= 0,299 Ф31 = 1

|[ [K ]−ω2 [M ] ]|{φ}=0

|[(5−3 λ ) −2 0−2 (3−2 λ ) −10 −1 (1− λ) ]|{φ

11

φ21

φ31}+{000 }=0

|[ ((5−3 λ )×φ11 )+(−2×φ

21)+(0×φ

31 )

(−2×φ11 )+((3−2 λ )×φ

21 )+(−1×φ

31 )

(0×φ11 )+(−1×φ

21 )+((1−λ )×φ

31 )

]|=0|[ ((5−3 λ )×φ

11 )+(−2×φ

21 )

(−2×φ11 )+((3−2 λ )×φ

21 )+(−1×1)

(−1×φ21 )+((1−λ )×1 )

]|=0|[ ((5−3×0 ,299)×φ

11 )+(−2×φ

21)

(−2×φ11 )+((3−2×0 ,299 )×φ

21 )+(−1×1 )

(−1×φ21 )+((1−0 ,299)×1)

]|=0|[ ( 4 ,103φ

11 )+(−2φ

21 )

(−2φ11 )+(2 ,402φ

21 )+(−1)

(−φ21 )+(0 ,701)

]|=0

Page 5: Multi Degree of Freedom (MDOF)

Dengan subtitusi mundur di dapat nilai:

(−φ21)+(0 ,701 )=0

φ21=0 ,701

(−2φ11)+(2 ,402φ

21 )+(−1)=0

(−2φ11)+(2 ,402×0 ,701)+(−1 )=0

(−2φ11)+(1 ,684−1 )=0

(−2φ11)+0 ,684=0

−2φ11=−0 ,684

2φ11=0 ,684

φ11=0 ,6842

=0 ,342

φ31=1

Untuk λ2= 1,304 Ф32 = 1

|[ [K ]−ω2 [M ] ]|{φ}=0

Page 6: Multi Degree of Freedom (MDOF)

|[(5−3 λ ) −2 0−2 (3−2 λ ) −10 −1 (1− λ) ]|{φ

12

φ22

φ32}+{000 }=0

|[ ((5−3 λ )×φ12 )+(−2×φ

22)+(0×φ

32)

(−2×φ12 )+((3−2 λ )×φ

22 )+(−1×φ

32 )

(0×φ12 )+(−1×φ

22 )+((1−λ )×φ

32 )

]|=0|[ ((5−3 λ )×φ

12 )+(−2×φ

22 )

(−2×φ12 )+((3−2 λ )×φ

22 )+(−1×1 )

(−1×φ22 )+((1−λ )×1 )

]|=0|[ ((5−3×1,304 )×φ

12 )+(−2×φ

22)

(−2×φ12 )+((3−2×1 ,304 )×φ

22 )+(−1×1 )

(−1×φ22 )+((1−1 ,304 )×1)

]|=0|[ (1,088φ

12 )+(−2φ

22 )

(−2φ12 )+(0 ,392φ

22 )+(−1)

(−φ22 )+(−0 ,304 )

]|=0Dengan subtitusi mundur di dapat nilai:

(−φ22)+(−0 ,304 )=0

φ22=−0 ,304

Page 7: Multi Degree of Freedom (MDOF)

(−2φ12)+(0 ,392φ

22 )+(−1)=0

(−2φ12)+(0 ,392×−0 ,304 )+(−1)=0

(−2φ12)+(−0 ,119−1 )=0

(−2φ12)+(−1 ,119 )=0

−2φ12=1 ,119

φ12=1,119

−2=−0 ,56

φ32=1

Untuk λ3= 2,563 Ф33 = 1

|[ [K ]−ω2 [M ] ]|{φ}=0

|[(5−3 λ ) −2 0−2 (3−2 λ ) −10 −1 (1− λ) ]|{φ

13

φ23

φ33}+{000 }=0

|[ ((5−3 λ )×φ13 )+(−2×φ

23 )+(0×φ

33 )

(−2×φ13 )+((3−2 λ )×φ

23 )+(−1×φ

33 )

(0×φ13 )+(−1×φ

23 )+((1−λ )×φ

33)

]|=0|[ ((5−3 λ )×φ

13 )+(−2×φ

23 )

(−2×φ13 )+((3−2 λ )×φ

23 )+(−1×1 )

(−1×φ23 )+((1−λ )×1 )

]|=0|[ ((5−3×2 ,563 )×φ

13 )+(−2×φ

23 )

(−2×φ13 )+((3−2×2,563 )×φ

23 )+(−1×1 )

(−1×φ23 )+((1−2 ,563)×1)

]|=0

Page 8: Multi Degree of Freedom (MDOF)

|[ (−2 ,689φ13 )+(−2φ

23 )

(−2φ13 )+(−2 ,126φ

23)+(−1 )

(−φ23 )+(−1 ,563 )

]|=0

Dengan subtitusi mundur di dapat nilai:

(−φ23 )+(−1,563 )=0

φ23=−1 ,563

(−2φ13 )+(−2 ,126φ

23 )+(−1)=0

(−2φ13 )+(−2 ,126×−1 ,563 )+(−1)=0

(−2φ13 )+(3 ,323 )+(−1)=0

(−2φ13 )+(2 ,323 )=0

(−2φ13 )=−2,323

φ13=−2 ,323

−2=1 ,1615

φ33=1

Page 9: Multi Degree of Freedom (MDOF)

φ31=1

φ21=0 ,701

φ11=0 ,304

Ragam 1

Untuk λ1= 0,299

λ= ω2

500 ⇒ω=√ λ×500=√0 ,299×500=12 ,227T=2π

ω= 2π12 ,227

=0 ,514

Page 10: Multi Degree of Freedom (MDOF)

φ22=−0 ,304

φ12=−0 ,560

φ32=1

F= 1T

= 10 ,514

=1 ,945

Ragam 2

Untuk λ2= 1,304

λ= ω2

500 ⇒ω=√ λ×500=√1 ,304×500=25 ,534

Page 11: Multi Degree of Freedom (MDOF)

φ23=−1 ,563

φ13=1 ,1615

φ33=1

T=2πω

= 2π25 ,534

=0 ,246

F= 1T

= 10 ,246

=4 ,065

Ragam 3

Untuk λ3= 2,563

Page 12: Multi Degree of Freedom (MDOF)

K

1

λ= ω2

500 ⇒ω=√ λ×500=√2 ,563×500=35 ,798

T=2πω

= 2π35 ,798

=0 ,175

F= 1T

= 10 ,175

=5 ,714

Kasus 2

m1

m2

m3

K

2

K3

Page 13: Multi Degree of Freedom (MDOF)

M1 = 2

M2 = 2

M3 = 2

K1 = 1500.00

K2 = 1000.00

K3 = 500.00

2 0 0[M] = 0 2 0

0 0 2

2500.00 -1000.00 0[K] = -1000.00 1500.00 -500.00

0 -500.00 500.00

|[K ]−ω2 [M ]|=0

|[2500 −1000 0−1000 1500 −5000 −500 500 ]−ω2 [2 0 0

0 2 00 0 2 ]|=0

500|[ 5 −2 0−2 3 −10 −1 1 ]−ω2[2 0 0

0 2 00 0 2 ]|=0

500|[(5−2ω2) −2 0

−2 (3−2ω2) −10 −1 (2−ω2 ) ]|=0

Page 14: Multi Degree of Freedom (MDOF)

Di asumsikan

λ= ω2

500

|[(5−2 λ ) −2 0−2 (3−2 λ ) −10 −1 (2−λ ) ]|=0

(5−3 λ )[3−2λ −1−1 (2−λ ) ]+2 [−2 −1

0 (2−λ ) ]−0=(5−3 λ ) {(3−2λ )(2−λ )−1 }+2 [−2(2−λ )]=

(5−3 λ ) {(3−2λ )(2−λ )−1 }−8+8 λ=

(5−3 λ )(6−3 λ−4 λ+2 λ2−1)−8+8 λ=

{5(6−3 λ−4 λ+2λ2−1 )−3 λ (6−3 λ−4 λ+2 λ2−1 )}−8+8 λ=30−15 λ−20 λ+10 λ2−5−18 λ+9 λ2+12λ2−6 λ3+3 λ−8+8 λ=−6 λ3+10 λ2+9 λ2+12 λ2−15 λ−20 λ−18 λ+3 λ+8 λ+30−5−8=−6 λ3+31 λ2−53 λ+3 λ+8 λ+17=

−6 λ3+31 λ2−53 λ+11 λ+17=

−6 λ3+31 λ2−42λ+17=

(−6 x3)+31 x2−42 x+17=0

Di dapat: (diurutkan dari nilai yang terkecil)

X1= λ1= 0,856

X2= λ2= 1

X3= λ3= 3,311

Page 15: Multi Degree of Freedom (MDOF)

Masukkan nilai –nilai di atas ke dalam persamaan

|[ [K ]−ω2 [M ] ]|{φ}=0

Untuk λ1= 0,856 Ф31 = 1

|[ [K ]−ω2 [M ] ]|{φ}=0

Page 16: Multi Degree of Freedom (MDOF)

|[(5−3 λ ) −2 0−2 (3−2 λ ) −10 −1 (2− λ) ]|{φ

11

φ21

φ31}+{000 }=0

|[ ((5−3 λ )×φ11 )+(−2×φ

21)+(0×φ

31 )

(−2×φ11 )+((3−2 λ )×φ

21 )+(−1×φ

31 )

(0×φ11 )+(−1×φ

21 )+((2−λ )×φ

31 )

]|=0|[ ((5−3 λ )×φ

11 )+(−2×φ

21 )

(−2×φ11 )+((3−2 λ )×φ

21 )+(−1×1)

(−1×φ21 )+((2−λ )×1 )

]|=0|[ ((5−3×0 ,856)×φ

11)+(−2×φ

21 )

(−2×φ11 )+((3−2×0 ,856 )×φ

21 )+(−1×1 )

(−1×φ21 )+((2−0 ,856 )×1)

]|=0|[ (2 ,432φ

11 )+(−2φ

21 )

(−2φ11 )+(1 ,288φ

21 )+(−1 )

(−φ21)+(1 ,144 )

]|=0Dengan subtitusi mundur di dapat nilai:

(−φ21)+(1,144 )=0

φ21=1 ,144

Page 17: Multi Degree of Freedom (MDOF)

(−2φ11)+(1 ,288φ

21 )+(−1)=0

(−2φ11)+(2 ,402×1 ,144 )+(−1 )=0

(−2φ11)+(2 ,748−1)=0

(−2φ11)+1 ,748=0

−2φ11=−1 ,748

2φ11=1 ,748

φ11=1,7482

=0 ,874

φ31=1

Untuk λ2= 1 Ф32 = 1

|[ [K ]−ω2 [M ] ]|{φ}=0

Page 18: Multi Degree of Freedom (MDOF)

|[(5−3 λ ) −2 0−2 (3−2 λ ) −10 −1 (2− λ) ]|{φ

12

φ22

φ32}+{000 }=0

|[ ((5−3 λ )×φ12 )+(−2×φ

22)+(0×φ

32)

(−2×φ12 )+((3−2 λ )×φ

22 )+(−1×φ

32 )

(0×φ12 )+(−1×φ

22 )+((2−λ )×φ

32 )

]|=0|[ ((5−3×1)×φ

12 )+(−2×φ

22)

(−2×φ12 )+((3−2×1 )×φ

22 )+(−1×1 )

(−1×φ22 )+((2−1)×1)

]|=0|[ (2×φ

12)+(−2×φ

22 )

(−2×φ12 )+(1×φ

22 )+(−1×1)

(−1×φ22 )+(1 )

]|=0|[ (2φ

12 )+(−2φ

22)

(−2φ12 )+(1φ

22 )+(−1)

(−φ22 )+(1)

]|=0Dengan subtitusi mundur di dapat nilai:

(−φ22)+(1)=0

φ22=−1

Page 19: Multi Degree of Freedom (MDOF)

(−2φ12)+(1φ

22 )+(−1 )=0

(−2φ12)+(1×−1 )+(−1)=0

(−2φ12)+(−1−1)=0

(−2φ12)+(−2)=0

−2φ12=2

φ12=2

−2=−1

φ32=1

Untuk λ3= 3,311 Ф33 = 1

|[ [K ]−ω2 [M ] ]|{φ}=0

|[(5−3 λ ) −2 0−2 (3−2 λ ) −10 −1 (2− λ) ]|{φ

13

φ23

φ33}+{000 }=0

|[ ((5−3 λ )×φ13 )+(−2×φ

23 )+(0×φ

33 )

(−2×φ13 )+((3−2 λ )×φ

23 )+(−1×φ

33 )

(0×φ13 )+(−1×φ

23 )+((2−λ )×φ

33 )

]|=0|[ ((5−3 λ )×φ

13 )+(−2×φ

23 )

(−2×φ13 )+((3−2 λ )×φ

23 )+(−1×1 )

(−1×φ23 )+((2−λ )×1)

]|=0

Page 20: Multi Degree of Freedom (MDOF)

|[ ((5−3×3,311 )×φ13 )+(−2×φ

23 )

(−2×φ13 )+((3−2×3,311)×φ

23 )+(−1×1)

(−1×φ23 )+((2−3,311)×1 )

]|=0|[ (−4 ,933 φ

13 )+(−2φ

23 )

(−2φ13 )+(−3 ,622φ

23)+(−1 )

(−φ23 )+(−1 ,311)

]|=0Dengan subtitusi mundur di dapat nilai:

(−φ23 )+(−1,311 )=0

φ23=−1 ,311

(−2φ13 )+(−3 ,622φ

23 )+(−1 )=0

(−2φ13 )+(−2 ,126×−1 ,311)+(−1)=0

(−2φ13 )+(2 ,787 )+(−1)=0

(−2φ13 )+(1 ,787 )=0

(−2φ13 )=−1,787

φ13=−1 ,787

−2=0 ,894

φ33=1

Page 21: Multi Degree of Freedom (MDOF)

φ31=1

φ21=1 ,144

φ11=0 ,874

Ragam 1

Untuk λ1= 0,856

λ= ω2

500 ⇒ω=√ λ×500=√0 ,856×500=20 ,688

T=2πω

= 2π20 ,688

=0 ,304

F= 1T

= 10 ,304

=3 ,293

Page 22: Multi Degree of Freedom (MDOF)

φ22=−1

φ12=−1

φ32=1

Ragam 2

Untuk λ2= 1

λ= ω2

500 ⇒ω=√ λ×500=√1×500=22 ,361

T=2πω

= 2π2 ,3612

=0 ,281

F= 1T

= 10 ,281

=3 ,559

Page 23: Multi Degree of Freedom (MDOF)

φ23=−1 ,311

φ13=0 ,894

φ33=1

Ragam 3

Untuk λ3= 3,311

λ= ω2

500 ⇒ω=√ λ×500=√3 ,311×500=40 ,688T=2π

ω= 2 π40 ,688

=0 ,154

F= 1T

= 10 ,154

=6 ,476