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CÁC CÔNG THỨC SỬ DỤNG TRONG PHƯƠNG PHÁP PHẦN TỬ HỮU HẠN - MÔ HÌNH CHUYỂN VỊ - BÀI TOÁN HỆ THANH 1. Thiết lập ma trận độ cứng phần tử 1.1 Ma trận độ cứng phần tử trong hệ toạ độ địa phương 1.1.1 Phần tử thanh hai đầu nút cứng (NN) l EJ l EJ l EJ l EJ l EJ l EJ l EJ l EJ l EF l EF l EJ l EJ l EJ l EJ l EJ l EJ l EJ l EJ l EF l EF K e 4 6 0 2 6 0 6 12 0 6 12 0 0 0 0 0 2 6 0 4 6 0 6 12 0 6 12 0 0 0 0 0 ] [ 2 2 2 3 2 3 2 2 2 3 2 3 (1) 1.1.2 Phần tử thanh đầu i nút cứng, đầu j khớp (NK) 0 0 0 0 0 0 0 3 0 3 3 0 0 0 0 0 0 3 0 3 3 0 0 3 0 3 3 0 0 0 0 0 ] [ 3 2 3 2 2 3 2 3 l EJ l EJ l EJ l EF l EF l EJ l EJ l EJ l EJ l EJ l EJ l EF l EF K e (2) 1.1.3 Phần tử thanh đầu i khp, đầu j nút cng (KN) l EJ l EJ l EJ l EJ l EJ l EJ l EF l EF l EJ l EJ l EJ l EF l EF K e 3 3 0 0 3 0 3 3 0 0 3 0 0 0 0 0 0 0 0 0 0 0 3 3 0 0 3 0 0 0 0 0 ] [ 2 2 2 3 3 2 3 3 (3)

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  • CC CNG THC S DNG TRONG PHNG PHP PHN T

    HU HN - M HNH CHUYN V - BI TON H THANH

    1. Thit lp ma trn cng phn t

    1.1 Ma trn cng phn t trong h to a phng

    1.1.1 Phn t thanh hai u nt cng (NN)

    l

    EJ

    l

    EJ

    l

    EJ

    l

    EJl

    EJ

    l

    EJ

    l

    EJ

    l

    EJl

    EF

    l

    EFl

    EJ

    l

    EJ

    l

    EJ

    l

    EJl

    EJ

    l

    EJ

    l

    EJ

    l

    EJl

    EF

    l

    EF

    Ke

    460

    260

    6120

    6120

    0000

    260

    460

    6120

    6120

    0000

    ][

    22

    2323

    22

    2323

    (1)

    1.1.2 Phn t thanh u i nt cng, u j khp (NK)

    000000

    03

    033

    0

    0000

    03

    033

    0

    03

    033

    0

    0000

    ][

    323

    22

    323

    l

    EJ

    l

    EJ

    l

    EJl

    EF

    l

    EFl

    EJ

    l

    EJ

    l

    EJl

    EJ

    l

    EJ

    l

    EJl

    EF

    l

    EF

    Ke (2)

    1.1.3 Phn t thanh u i khp, u j nt cng (KN)

    l

    EJ

    l

    EJ

    l

    EJl

    EJ

    l

    EJ

    l

    EJl

    EF

    l

    EF

    l

    EJ

    l

    EJ

    l

    EJl

    EF

    l

    EF

    Ke

    3300

    30

    3300

    30

    0000

    000000

    3300

    30

    0000

    ][

    22

    233

    233

    (3)

  • 1.2 Ma trn cng phn t trong h to tng th

    1.2.1 Ma trn chuyn phng

    100000

    0cossin000

    0sincos000

    000100

    0000cossin

    0000sincos

    ][

    T (4)

    1.2.2 Ma trn cng phn t trong h to tng th

    ]].[.[][]'[ TKTK eT

    e (5)

    2. Quy i ti trng phn t thnh lc nt tng ng

    2.1 Quy i ti trng tc dng trn phn t (theo phng h to a phng) v

    thnh lc nt tng ng theo phng h to a phng

    2.1.1 Phn t thanh hai u nt cng (NN)

    * Do lc phn b u px:

    ( )

    1 1. 0 0 . 0 0

    2 2x

    T

    e x xpR p l p l

    (6)

    * Do lc phn b u py:

    2 2( )

    1 1 1 10 . . 0 . .

    2 12 2 12y

    T

    e y y y ypR p l p l p l p l

    (7)

    * Do ti trng tp trung T:

    ( )

    . .0 0 0 0

    T

    e T

    T b T aR

    l l

    (8)

    * Do ti trng tp trung P:

    2 2 2 2

    3 2 3 2( )0 ( 2 ) 0 (3 2 )

    T

    e P

    Pb Pab Pa Pa bR l a l a

    l l l l

    (9)

    * Do moment tp trung M:

    3 2 3 2( )

    6 60 (2 ) 0 (2 )

    T

    e M

    Mab Mb Mab MaR a b b a

    l l l l

    (10)

    2.1.2 Phn t thanh u i nt cng, u j khp (NK)

    * Do lc phn b u px:

  • ( )

    1 1. 0 0 . 0 0

    2 2x

    T

    e x xpR p l p l

    (11)

    * Do lc phn b u py:

    2( )

    5 1 30 . . 0 . 0

    8 8 8y

    T

    e y y ypR p l p l p l

    (12)

    * Do ti trng tp trung T:

    ( )

    . .0 0 0 0

    T

    e T

    T b T aR

    l l

    (13)

    * Do ti trng tp trung P:

    2 2

    2 2 2( )0 (3 ) (2 ) 0 (3 ) 0

    2 2 2

    T

    e P

    Pb b Pab Pa aR l a

    l ll l l

    (14)

    * Do moment tp trung M:

    2 2 2

    2 2 2( )

    3 30 (1 ) (1 3 ) 0 (1 ) 0

    2 2 2

    T

    e M

    M b M b M bR

    l ll l l

    (15)

    2.1.3 Phn t thanh u i khp, u j nt cng (KN)

    * Do lc phn b u px:

    ( )

    1 1. 0 0 . 0 0

    2 2x

    T

    e x xpR p l p l

    (16)

    * Do lc phn b u py:

    2( )

    3 5 10 . 0 0 . .

    8 8 8y

    T

    e y y ypR p l p l p l

    (17)

    * Do ti trng tp trung T:

    ( )

    . .0 0 0 0

    T

    e T

    T b T aR

    l l

    (18)

    * Do ti trng tp trung P:

    2 2

    2 2 2( )0 (3 ) 0 0 (3 ) (2 )

    22 2

    T

    e P

    Pb b Pa a PabR l b

    l ll l l

    (19)

    * Do moment tp trung M:

    2 2 2

    2 2 2( )

    3 30 (1 ) 0 0 (1 ) (1 3 )

    2 2 2

    T

    e M

    M a M a M aR

    l ll l l

    (20)

  • Vect ti trng nt tng ng do ti trng tc dng trn phn t quy i thnh

    lc nt tng ng theo phng h to a phng:

    ( ) ( ) ( ) ( ) ( )x y

    e e e e e ep p T P MR R R R R R (21)

    2.2 Quy i ti trng tc dng trn phn t (theo phng h to a phng) v

    thnh lc nt tng ng theo phng h to tng th:

    eT

    e RTR .][' (22)

    3. Lp ma trn cng tng th, xc nh chuyn v nt, xc nh ni lc:

    3.1 Lp ghp:

    Ma trn ]'[ eK ca tng phn t ma trn ][ SK .

    Vect }'{ eR ca tng phn t vect }'{ SR

    Cng vect }'{ SR vi vect ti trng tc dng trc tip ti nt }{ PR vect

    lc tng cng ti nt }{ SR

    }{}'{}{ PSS RRR (23)

    3.2 Xt iu kin bin, kh trng lp:

    Ma trn ][ SK ma trn ]*[ sK

    Vect }{ SR vect }*{ SR

    3.3 Gii h phng trnh: SSS RuK **.*

    }*{*}*{ 1 SSS RKu

    (24)

    3.4 Vect chuyn v nt ca phn t:

    Lp ghp cc chuyn v nt (gm nhng chuyn v ti cc lin kt v nhng

    chuyn v xc nh t kt qu gii h phng trnh) vect chuyn v nt ca phn t trong

    h to tng th eu' .

    Vect chuyn v nt ca phn t trong h to a phng eu .

    }'{}{ ee uTu (25)

    3.5 Vect ni lc ca phn t:

    eeee RuKF }{}{ (26)

    Ni lc ti 2 u thanh:

    )1(ei

    FN ; )2(ei

    FQ ; )3(ei

    FM (27)

    )4(ej

    FN ; )5(ej

    FQ ; )6(ej

    FM

  • 1. Ri rc ha kt cu v lp bng s liu:

    + Tin hnh ri rc kt cu thnh 2 phn t v 3 nt.

    + Bng s liu phn t:

    Phn t Nt i Nt j E.J E.F l Cos() Sin() Loi PT

    1 1 2 2'560 192'000 4 1 0 NN

    2 2 3 1'080 144'000 5 0.8 -0.6 NK

    + Bng s liu ti trng trn phn t:

    Phn t px py T a b P a b M a b

    1 -1.8

    2 2.4 2.5 2.5 -3.2 2.5 2.5

    + Bng s liu ti trng tc dng ti nt:

    Nt PX PY MZ

    2 -5

    + Bng s liu iu kin bin:

    Nt uX uY rZ

    1 0 0 0

    2 0 0 0

    3 0 0 khng x

    2. Thit lp ma trn cng phn t:

    2.1. Phn t 1: (p dng cng thc 1, 4, 5)

    Ma trn [Ke]

    48'000 0 0 -48'000 0 0

    0 480 960 0 -480 960

    0 960 2'560 0 -960 1'280

    -48'000 0 0 48'000 0 0

    0 -480 -960 0 480 -960

    0 960 1'280 0 -960 2'560

    Ma trn [T]

    1 0 0 0 0 0

    0 1 0 0 0 0

    0 0 1 0 0 0

    0 0 0 1 0 0

    0 0 0 0 1 0

    0 0 0 0 0 1

  • Ma trn [T]T

    1 0 0 0 0 0

    0 1 0 0 0 0

    0 0 1 0 0 0

    0 0 0 1 0 0

    0 0 0 0 1 0

    0 0 0 0 0 1

    K'e (1) (2) (3) (4) (5) (6)

    (1) 48'000.0 0.0 0.0 -48'000.0 0.0 0.0

    (2) 0.0 480.0 960.0 0.0 -480.0 960.0

    (3) 0.0 960.0 2'560.0 0.0 -960.0 1'280.0

    (4) -48'000.0 0.0 0.0 48'000.0 0.0 0.0

    (5) 0.0 -480.0 -960.0 0.0 480.0 -960.0

    (6) 0.0 960.0 1'280.0 0.0 -960.0 2'560.0

    2.2. Phn t 2: (p dng cng thc 2, 4, 5)

    Ma trn [Ke]

    28'800.0 0.0 0.0 -28'800.0 0.0 0.0

    0.0 25.9 129.6 0.0 -25.9 0.0

    0.0 129.6 648.0 0.0 -129.6 0.0

    -28'800.0 0.0 0.0 28'800.0 0.0 0.0

    0.0 -25.9 -129.6 0.0 25.9 0.0

    0.0 0.0 0.0 0.0 0.0 0.0

    Ma trn [T]

    0.8 -0.6 0 0 0 0

    0.6 0.8 0 0 0 0

    0 0 1 0 0 0

    0 0 0 0.8 -0.6 0

    0 0 0 0.6 0.8 0

    0 0 0 0 0 1

    Ma trn [T]T

    0.8 0.6 0 0 0 0

    -0.6 0.8 0 0 0 0

    0 0 1 0 0 0

    0 0 0 0.8 0.6 0

    0 0 0 -0.6 0.8 0

    0 0 0 0 0 1

  • K'e (4) (5) (6) (7) (8) (9)

    (4) 18'441.3 -13'811.6 77.8 -18'441.3 13'811.6 0.0

    (5) -13'811.6 10'384.6 103.7 13'811.6 -10'384.6 0.0

    (6) 77.8 103.7 648.0 -77.8 -103.7 0.0

    (7) -18'441.3 13'811.6 -77.8 18'441.3 -13'811.6 0.0

    (8) 13'811.6 -10'384.6 -103.7 -13'811.6 10'384.6 0.0

    (9) 0.0 0.0 0.0 0.0 0.0 0.0

    3. Quy i ti trng phn t thnh lc nt tng ng:

    3.1. Phn t 1: (p dng cng thc 7, 21, 22)

    ( )

    0 3.6 2.4 0 3.6 2.4y

    T

    e pR

    0 3.6 2.4 0 3.6 2.4T

    eR

    T{ 0 3.6 2.4 0 3.6 2.4' }(1) (2) (3) (4) (5) (6)

    eR

    3.1. Phn t 2: (p dng cng thc 13, 14, 21, 22)

    ( )

    1.2 0 0 1.2 0 0T

    e TR

    ( )

    0 2.2 3.0 0 1.0 0T

    e PR

    1.2 2.2 3.0 1.2 1.0 0T

    eR

    T{ 0.36 2.48 3.0 0.36 1.52 0' }(4) (5) (6) (7) (8) (9)

    eR

    4. Lp ma trn cng tng th, xc nh chuyn v nt, xc nh ni lc:

    4.1 Lp ghp:

    + Ma trn cng ton h SK :

    (1) (2) (3) (4) (5) (6) (7) (8) (9)

    (1) 48000.0 0.0 0.0 -48000.0 0.0 0.0 0.0 0.0 0.0

    (2) 0.0 480.0 960.0 0.0 -480.0 960.0 0.0 0.0 0.0

    (3) 0.0 960.0 2560.0 0.0 -960.0 1280.0 0.0 0.0 0.0

    (4) -48000.0 0.0 0.0 66441.3 -13811.6 77.8 -18441.3 13811.6 0.0

    (5) 0.0 -480.0 -960.0 -13811.6 10864.6 -856.3 13811.6 -10384.6 0.0

    (6) 0.0 960.0 1280.0 77.8 -856.3 3208.0 -77.8 -103.7 0.0

    (7) 0.0 0.0 0.0 -18441.3 13811.6 -77.8 18441.3 -13811.6 0.0

    (8) 0.0 0.0 0.0 13811.6 -10384.6 -103.7 -13811.6 10384.6 0.0

    (9) 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0

  • + Vect lc nt ton h SR :

    - Lp ghp cc vect lc nt do ti trng tc dng trn phn t quy i v nt:

    T{ 0 3.6 2.4 0.36 6.08 0.6 0.36 1.52 0' }(1) (2) (3) (4) (5) (6) (7) (8) (9)

    SR

    - Cng vi lc tc dng trc tip ti nt:

    T{ 0 3.6 2.4 0.36 11.08 0.6 0.36 1.52 0 }(1) (2) (3) (4) (5) (6) (7) (8) (9)

    SR

    4.2 Xt iu kin bin, kh trng lp:

    - B cc hng v ct trong ma trn SK c s th t tng ng vi bc t do ca nt c

    lin kt, hoc khng xc nh (1, 2, 3, 7, 8, 9) *SK

    Ma trn cng [K*]S

    66'441.33 -13'811.56 77.76

    -13'811.56 10'864.59 -856.32

    77.76 -856.32 3'208.00

    - B cc hng trong vect SR c s th t tng ng vi bc t do ca nt c lin kt,

    hoc khng xc nh (1, 2, 3, 7, 8, 9) *SR

    T{ 0.36 11.08 0.6* }(4) (5) (6)

    SR

    - B cc hng trong vect SR c s th t tng ng vi bc t do ca nt c lin kt,

    hoc khng xc nh (1, 2, 3, 7, 8, 9) *SR

    4.3 Gii h phng trnh: SSS RuK **.*

    }*{*}*{ 1 SSS RKu

    Ma trn [K*]-1S

    2.0594E-05 2.6702E-05 6.6285E-06

    2.6702E-05 0.00012864 3.3692E-05

    6.6285E-06 3.3692E-05 0.00032055

    T{ 0.0003073 0.0014552 0.000568* }(4) (5) (6)

    Su

    4.4 Vect chuyn v nt ca phn t:

    Lp ghp cc chuyn v nt (gm nhng chuyn v ti cc lin kt v nhng

    chuyn v xc nh t kt qu gii h phng trnh) vect chuyn v nt ca phn t trong

    h to tng th eu' .

  • Xc n vect chuyn v nt ca phn t trong h to a phng eu .

    { } { ' }e e eu T u

    + Phn t 1:

    T{ 0 0 0 0.0003073 0.0014552 0.000568' }(1) (2) (3) (4) (5) (6)

    eu

    0 0 0 0.0003073 0.0014552 0.000568T

    eu

    + Phn t 2:

    T{ 0.0003073 0.0014552 0.000568 0 0 0' }(4) (5) (6) (7) (8) (9)

    eu

    0.0006273 0.0013485 0.000568 0 0 0T

    eu

    3.5 Vect ni lc ca phn t:

    eeee RuKF }{}{

    Ni lc ti 2 u thanh:

    )1(ei

    FN ; )2(ei

    FQ ; )3(ei

    FM

    )4(ej

    FN ; )5(ej

    FQ ; )6(ej

    FM

    + Phn t 1:

    14.748 3.753 3.070 14.748 3.447 2.457T

    eF

    Ni lc ti 2 u thanh:

    14.748iN ; 3.753iQ ; 3.070iM

    14.748jN ; 3.447jQ ; 2.457jM

    + Phn t 2:

    16.867 2.091 2.457 19.267 1.109 0T

    eF

    Ni lc ti 2 u thanh:

    16.867iN ; 2.091iQ ; 2.457iM

    19.267jN ; 1.109jQ ; 0jM