tm-ii chapt-1-2007-11-11

68
1 Ι. Βαρδουλάκης:Τεχνική Μηχανική ΙΙ, Κεφ. 1, 2007 1 ΕΦΕΛΚΥΣΜΟΣ ΚΑΙ ΘΛΙΨΗ ΡΑΒ∆ΩΤΩΝ ΦΟΡΕΩΝ 1.1 Η Τάση 1 Για να εισάγουμε την έννοια της τάσης θα θεωρήσουμε το παράδειγμα μιας εφελκυόμενης ευθύγραμμης ράβδου (ΑΒ), που έχει σταθερή διατομή καθέτως προς τον άξονά της, εμβαδού A . Στα άκρα της ράβδου αυτής ασκούνται δύο αντίθετες δυνάμεις , έντασης F , οι οποίες δρουν κατά μήκος του άξονά της, δηλαδή της ευθείας ( ) AB που ενώνει τα κέντρα βάρους των ορθών διατομών της 2 . Μία τέτοια φόρτιση λέγεται κεντρική φόρτιση. Η κεντρική φόρτιση της ράβδου προκαλεί την ανάπτυξη μόνον εσωτερικών αξονικών δυνάμεων x N N = , οι οποίες για λόγους ισορροπίας εμφανίζονται να δρουν πάνω σε διατομές, που προκύπτουν από ιδεατές τομές (Τ-Τ) σε τυχαία θέση x , καθέτως προς τον άξονα της ράβδου. Με άλλα λόγια με την κεντρική φόρτιση της ράβδου αποφεύγουμε την ανάπτυξη ροπών κάμψης. Από το αντίστοιχο διάγραμμα ελεύθερου σώματος, ισορροπία σε κάθε τομή στη θέση x , δίδει 0: x F N F + →Σ = = (1.1) Στα πλαίσια της Στατικής η φόρτιση θεωρείται ότι λαμβάνει χώρα «αργά» και την ονομάζουμε ως μια «οιονεί στατική φόρτιση». Σε μία τέτοια θεώρηση ο χρόνος υπεισέρχεται στη διατύπωση του προβλήματος μόνον έμμεσα, π.χ. θεωρώντας ότι το επιβαλλόμενο φορτίο είναι συνάρτηση του χρόνου, () F Ft = . Στην περίπτωση αυτή θεωρούμε ότι οι οποιεσδήποτε χρονικές μεταβολές του φορτίου είναι αρκετά «αργές», έτσι ώστε οι συνεπακόλουθες επιταχύνσεις των υλικών σημείων του σώματος να είναι αμελητέες και ως εκ τούτου ανά πάσα στιγμή να ισχύει στο ελεύθερο σώμα ο νόμος ισορροπίας των δυνάμεων, Εξ. (1.1). 1 Αγγλ. stress 2 Ορθή διατομή καλείται η διατομή που εμφανίζεται με μία τομή κάθετα προς τον άξονα της ράβδου.

Upload: panagiotis-stamatis

Post on 09-Nov-2015

230 views

Category:

Documents


2 download

DESCRIPTION

ΤΕΧΝΙΚΗ ΜΗΧΑΝΙΚΗ 2 ΚΕΦ.1-ΒΑΡΔΟΥΛΑΚΗΣ

TRANSCRIPT

  • 1 . : , . 1, 2007

    1

    1.1 1

    (), , A . , F , , ( )AB 2. . xN N= , , (-) x , . . , x ,

    0 :xF N F+ = =

    (1.1)

    . , .. , ( )F F t= . , , . (1.1).

    1 . stress 2 .

  • 2 . : , . 1, 2007

    - x , . ( , )P y z+ ( , )P y z . P+ dA P+ , dN+ . dN . 3

    dN dN+ = (=) (1.2)

    dN dN dN+ = = (1.3)

    dNdA

    = (1.4)

    (1.4) . dN , 3. . , ( ),.

    ( , , , )x y z t = (1.5) dN ,

    3 . normal stress

  • 3 . : , . 1, 2007

    ( ) ( )A AN dN dA= = (1.6)

    , , ,

    ( )A

    NN dA AA

    = = = (1.7) E. (1.7) . . (1.1) (1.7) ,

    .FA

    = = (1.8)

    (1.7) . , z y . , dN dA= , ,

    ( )0z

    Ay dA = (1.9)

    y(A)

    M z dA 0= (1.10) . 6, (1.9), (1.10), xN N= zM yM z y . , :

  • 4 . : , . 1, 2007

    ( ) ( )0 0 , 1,2,n n

    A Ay dA z dA n = = = (1.11)

    :

    , ,

    0 0N > > (1.12) , , ,

    0 0N < < (1.13) . , . (1.12) (1.13), .

    ,. (1.4), . ,

    2[ ] FL = (1.14)

    2Pa Nm= , 310kPa Pa= , 310MPa kPa= ...

    , 10F kN= , , 21A cm= . , . (1.8) ,

    ( )5

    2 2 4 2 22

    5

    10 10 10 101 1010

    10 100 0.1

    F kN kN kN kNA cm m mm

    kPa MPa GPa

    = = = = =

    = = =

  • 5 . : , . 1, 2007

    1.2

    ( ). n, x . nA ,

    cosnAA = (1.15)

    ( 0 = ). 4

    n nx xt t e=G G (1.16) , x ,

    xN N= , , 0nx n nyt A N t= = (1.17)

    cos/ cosnx n

    N NtA A

    = = = (1.18)

    nt n , n , . 5.

    4 . traction vector. 5 . shear stress.

  • 6 . : , . 1, 2007

    , ( , )x y . , :

    0 : cos

    0 : sin

    n n nx n

    n n nx n

    F A t A

    F A t A

    = =

    = = (1.19)

    . (1.19) . Error! Reference source not found. ,

    2cos

    sin cos

    n

    n

    =

    = (1.20)

    , . n ={ , ,x y zn n n }

    . , n .

    ( 0 = ) , , n n . . (1.20) . ( , )x y ( 1, 0x yn n= = ) ,

    , 0nx nyt t= = (1.21)

    ( cos , sinx yn n = = ) 2cos , sin cosn nt t = = (1.22)

  • 7 . : , . 1, 2007

    , . (1.20) . . 2. . (1.20) ,

    cos 22 2

    sin 22

    n

    n

    = +

    = (1.23)

    ( ),n n ,

    ( )2 22 2 2cos 2 sin 22 2n n + = + 2 2

    22 2n n + = (1.24)

    . 2, E.(1.23) , 2 ., Mohr .

    , . ( ) : ) , ) .

    :

    ) . (1.20) ,

    0ndd =

  • 8 . : , . 1, 2007

    ,

    1

    2

    02 cos sin 0

    2

    = = = =

    ,

    21 2

    0 ( 0) :0 : , 0 , 2

    0 ( 0) :n

    n ndd

    < >= = = = = > >

    22 2

    0 ( 0) :: 0 , 0 , 2

    0 ( 0) :2n

    n ndd

    > >= = = = = + < = > >

  • 9 . : , . 1, 2007

    4

    2

    2

    / 4 : / 2 , / 2

    0 ( 0) :2

    0 ( 0) :

    n n

    ndd

    = = = =

    < >= > >

    45D . . , .

    . (.. ) , , , , . , , . 6. (.. ) , l 45D , , , . ( 7).

    6 . Mode I 7 . Mode I.

  • 10 . : , . 1, 2007

    1.3 8

    (), . (AB) A . = + A A A . 9 ,

    = AA (1.25)

    , ,

    [ ] 1 = (1.26)

    :

    , ( 0 >A ), . ( 0

  • 11 . : , . 1, 2007

    0.5mstrain = .

    , . (1.25), 11, , 1

  • 12 . : , . 1, 2007

    ( )x

    dux x dx u x dxdx

    = + + + (1.28)

    x , ,

    : ( )d x dx x dx= + =A :

    ( )( ) ( )x x

    du dud x dx u x dx x u x dx dxdx dx

    = + + + + = + A

    : x

    dud d d dxdx

    = = A A A

    x , . (1.25), ,

    x

    d dud dx

    = = AA (1.29)

    , . x ,

    . (0)du u u xdx

    = = = + (1.30)

    . . , ,

    (0) 0u = (1.31) ,

    ( )u x u = = = = AA A A A (1.32)

  • 13 . : , . 1, 2007

    . (Machu Picchu, Peru, . . 2006).

    , . (1.25), 13. . (1.29) , dA x , . , . , .

    13 . engineering strain

  • 14 . : , . 1, 2007

    1.5 -

    1.5.1 Hooke

    14..

    , , , . 15 . ,

    ( ) = (1.33) . . (1.33), 16. -, - -. , -

    14 . , . , . . (2002). : . , (. - & . , .) . , . 187-210. 15 . 16 . constitutive equation

  • 15 . : , . 1, 2007

    0

    d Ed =

    = + " (1.34)

    -, Hooke17. E. (1.34) E - Young. , ,

    2[ ]E FL= (1.35) 2/kN mm , ,

    ( )6 6

    22 231 1 10 10 1

    10

    kN kN kN kPa GPamm mm

    = = = = (1.36)

    .. Young 75GPa .

    E , Young, . Thomas Young (1807) ( )EA , A , /E , 18. Young , , -.

    17 Robert Hooke (1635-1703) : ut tensio sic vis. 18 J.F. Bell, 1973, The Experimental Foundations of Solid Mechanics, Springer, Sect. 3.7, p. 186.

  • 16 . : , . 1, 2007

    . - , . A , Y , Hooke, = ( ). . . Y ( ). . 19. , F . . ( / ) F =A A , , .

    19 , . hardening

  • 17 . : , . 1, 2007

    , ( ) , . (. ). , () , , (), (;). ,

    (0 1)G = < , ( 0 > ). Hooke (1.34) (1.40) - , . -,

    20 . shear modulus

  • 18 . : , . 1, 2007

    ( ) ( )

    ( )T E TE = + = + = (1.41)

    Young .

    2kN

    mm

    210

    74

    70

    30

    10

    6 o110C

    11

    3 9

    22

    12

    3 9

    , ,

    0 0T = = (1.42) 21. , . .

    (), . - (;). , ,

    21 . workless thermal strain

  • 19 . : , . 1, 2007

    . 0 = =A ( ( )= A ). , . - . (1.41) ,

    0 T E TE = + =

    0 > ( 0 < ), ( 0 < ) ( 0 > ). .. ,

    2210. /kN mm = 6 111. 10 oC = , 6 6

    2 3 21 1210 11 10 2310 10 2.31

    (10 )o o okN kN MPaT T T

    mm C m C C = = =

    22 St, 220MPa = , , < , ( max, < ) ,

    omax,o o

    MPa 220MPa2.31 T 220MPa 95.2 CC 2.31MPa / C

    = < = = =

    L.F. Coffin (1979) & S.S. Mason (1960)23 , , - , - .

    22 . , . , , , , . 23 S.S. Manson , Interpretive report on cumulative fatigue damage in the low cycle range. Weld. J. Res. Suppl. 43 (1964), pp. S344S352..

  • 20 . : , . 1, 2007

    - . .

    , () () , -, . T 0 > , . Maxwell () C.R. Calladine (1978)24. Maxwell , 3 n = + , , n 25. Calladine, 3 n s m = + + , s m .

    24 C.R. Calladine, Buckminster Fullers Tensegritty structures and Clerk Maxwells rules for the construction of stiff frames, Int. J. Solids Structures, 14 (1978), pp. 161-172. 25 . . . , , . 3, . , 2004.

  • 21 . : , . 1, 2007

    1.5.3

    A , 26 S . , A , E . ,

    SA

    = (1.43)

    A ,

    = AA (1.44)

    Hooke,

    E = (1.45) ,

    ( )S EA = AA (1.46)

    ( )EA 27 . E. (1.45) ,

    TE = + (1.47)

    E. (1.46) ,

    ( )S EA T = AA (1.48)

    26 S , , . 27 , stiffness.

  • 22 . : , . 1, 2007

    1.6

    1.6.1

    . (;). , RA, R 28 S1 S2 . ,

    1 2S S S= = (1.49)

    2 cos 0

    12 cos

    S FFS

    = = (1.50)

    . (1.46) ,

    SEA

    =A A (1.51)

    , + A A , .

    :

    2

    ( )cos

    1 12 cos

    FEA

    =

    =

    A

    A (1.52)

    28 , , . , stress. . , . (1.43).

  • 23 . : , . 1, 2007

    :

    SA

    = 12 cos

    FS =

    (),

    :

    S

    : 3m=A , o30 = , F 30kN= , 2210 /E kN mm= , 220MPa = . :

    4 2 2

    32

    1 30 1 0.787 10 0.7872 cos30 220 10

    okN m cmkN

    m

    = =

    .. , D ,

    4 0.01001 10.01D D A m mm = = =

    12.5D mm= ,

    ( )2 2 -4 2 20.0125 1.227 10 m 1.2274 4

    DA m cm= = = =

    :

    2

    1 1 1 1 30 141140.2kPa=141.1MPa2 cos 2 cos30 0.0001227mo

    S F kNA A

    = = = =

    ,

    141.1MPa

  • 24 . : , . 1, 2007

    ( )

    22

    2-3

    223

    141140.2

    210 0.0001227m

    141140.20.0055=5.5 10

    210 0.0001227m10

    kPakNA

    mmkNm

    kNm

    = = =

    = =

    AA

    ( 1

  • 25 . : , . 1, 2007

    ( )* 3 2 31 1 1cos tan tan6 2 3

    = = + +"A (1.53)

    () ,

    ( )22 2 2( ) 2 cos2

    A = + = + A A A A (1.54)

    ( )* *2 2 211 2 sin 12

    = = + AA (1.55)

    Hooke29, ,

    ( )S EA = AA (1.56)

    ,

    *

    ( )SS

    EA= (1.57)

    Hooke ( ) ,

    *S = (1.58) , , , ,

    11 12 sin 2 6

    F FS = + (1.59)

    / 2 = . (1.50) (. ), . (1.59) (. ). (1.50) ,

    29 .

  • 26 . : , . 1, 2007

    (1.59) . , . (1.55) (1.59) - 30 . ,

    ( )FEA

    = (1.60)

    . (1.59) ,

    * 11 12 sin 2 6

    S = + (1.61)

    . (1.58), (1.55) (1.61) , - ,

    2 2( ) (1.62)

    . (1.62), , : (0), ,

    : 0 = = (1.63) , . , , . (1.62), (1) ,

    30 - .

  • 27 . : , . 1, 2007

    3max

    1 2:3 3 3

    = = = (1.64)

    (1) , , (1) . (1.62) , (1-2-1) . , 0 = , (1-2-1), 31 , . , 32 ( 1) ( 1) , (1-1). (1-1) , 33 . 34 35 .

    1.6.3

    () () ( 0 = ). F , , . (1.50) ( / 2 ) . , , . , 0 = .(1.53) (1.62) ,

    3 *3 * 3 (1.65)

    31 , . softening branch. 32 . . 33 , . snap-through. . Durchschlagen. Richard von Mises. 34 von Mises R. (1923). ber die Stabilittsprobleme der Elastiyittatheorie, ZAMM, 3, 406-422. von Mises R. und Ratzerdorfer, J. (1925). Die Knicksicherheit von Fachwerken, ZAMM,5, 218-235. 35 Huang, N. C. (1972) Dynamic buckling of a some elastic shallow structure subjected to periodic loading with high frequency, International Journal of Solids and Structures, 8, 315326.

  • 28 . : , . 1, 2007

    . (1.61) ,

    * *212

    S (1.66)

    , , ,

    1/3

    ( )FEA

    A (1.67)

    2 /31( )2 ( )

    FS EAEA

    (1.68)

    , , - .. .

    1.6.4

    , ' :

    1 (0 1)= + <

  • 29 . : , . 1, 2007

    (1) (2) (3) :

    1( ') 0( ) ( ) 0OOOO OO

    = > = = . ,

    1 2N N N= = (2),

    0 1T T T = +

    (1): 1d NL EA

    = =

    (2): 2 0 1 1d N d NT T

    L EA L EA += = + = +

    ,

  • 32 . : , . 1, 2007

    112

    NL NLd T N EA TEA EA

    = = + =

    (1) (2)

    1 112

    N E TA

    = = ( )

    2 112

    N E TA

    = = ( )

    10

    3/ 10 . (1) 36. (1) 1 = . ,

    31, 1, 5

    1 1 1 1 12 2 10 2010 2 10 10 10

    E T CC

    = = = =

    DD

    (2)

    0 1 100 20 120T T T = + = + =D D D . 2) () ()

    T . ().

    36 . .

  • 33 . : , . 1, 2007

    :

    :

    2 2

    cos

    a ba

    = +=

    A

    A

    ():

    0 :yF+ = 1 2( )sin ( )sin ) 0S S + = 1 2S S S= = (1.78) 0 :xF

    + = 1 2 1 2( ) ( ) cos ( )cos 0N N S S + = 2 1

    1cos ( )2

    S N N = (1.79)

    -, :

    TE = +

    :( )

    S TEA

    = + AA

    : 1( )

    Naa EA =

    : 2( )

    Ncc EA =

  • 34 . : , . 1, 2007

    :

    ) :

    :

    c c a a c a+ + + = + c a = Hooke ,

    2 1( ) ( )

    N Nc aEA EA

    = 2 1aN Nc= (1.80)

    . (1.79) :

    2 1 11 1cos ( ) (1 )2 2

    aS N N Nc

    = = + 1 2 cos1 /N Sa c = + (1.81)

    ) ():

    1 cos( ) ( )

    N Sa TEA EA

    = + A (1.82)

  • 35 . : , . 1, 2007

    . (1.81) (1.82) ,

    2( )2 1cos ( )

    1 / ( ) cosEAS S EA T

    a c EA

    = + +

    3

    ( )( )2 cos

    1 / ( )

    EA TS EA

    a c EA

    = ++

    S , . (1.81) (1.80).

    3) , 1 3( ) ( ) ( )EA EA EA= = , 2( ) 2( )EA EA= .

    .

    4) , () , (). F. .

  • 36 . : , . 1, 2007

    5) ( ) (F = 0), (2) C. .

    6) , , . = 30C. , , , . : , = 70 GPa, = 23 .10-6 /oC = 3 cm2.

    7) Ac , () As. () () . : ) c s . ) c s , (-) . , Ec = 25 GPa , ESt = 200 GPa. , Ac = 400cm2 , ASt = 4 cm2. ac=10 .10-6/oC St= 12 .10-6/oC. , = 200kN, , = 20C.

  • 37 . : , . 1, 2007

    :

    Z ( )s D ( )c :

    Z D= 0L ,

    0 0 0c sL L L= =

    100Z P kN= =

    ( )s : 0 2 2100. 250

    4. (10 )St

    St

    P kN MPaA m

    = = =

    ( )c : 0 2 2100. 2.5

    400. (10 )c

    c

    P kN MPaA m

    = = =

    Z D 20T C = D .

    Z D P = =

    P P P = +

  • 38 . : , . 1, 2007

    ( )s : / StSt StSt

    P A TE

    = +

    ( )c : / cc cc

    P A TE

    = +

    o ,

    0 (1 )c St st cL L L = = + = = :

    / /St cSt c

    St c

    P A P AT TE E

    = + = + ( )1 1St c

    St St c c

    TP

    E A E A

    = +

    ( )s : 492.6Stst

    P MPaA

    = =

    ( )c : 4.9cc

    P MPaA

    = =

    8) (), . ,

    1 2 3, 2 , 3= = =A A A A A A . , a , 2a 3a , . , Fx b= , F . : ,

    5 22.1 10 /StE E N mm= = , , 21.2A mm= , , 2.5F kN= , 1.5a m=

    0.25m=A . : 1) . 2) , ( 2b a= ).

  • 39 . : , . 1, 2007

    1.8

    . , , ( )x = .

    1.8.1

    ', . '. x

    0N dN dB NdN dB+ = = (1.83)

    37 ( )A x

    x .

    1( ) , [ ]A x FL = = (1.84) dB ,

    ( )dB x dx= (1.85) , . (1.83), :

    ( )dN xdx

    = (1.86)

    . (1.84) (1.86) ( )N x ( )A x = x :

    37 .. , 325 /kN m =

  • 40 . : , . 1, 2007

    ( )dN A xdx

    = (1.87)

    ,

    0 0

    0

    ( )

    ( ) (0) ( ) ; ( ) ( )

    x x

    x

    dN A d

    N x N V x V x A d

    =

    = =

    x ,

    ( ) ( )B x V x=

    ( ) (0) ( )N x N B x= + (1.88) AV , , . . (1.88) x H= ,

    ( ) (0)(0) ( ) 0 ( )

    N H F N BN B F

    = = + = + < (1.89)

    ( ) ( ( ))N x F B B x= ( ) ( ( ))N x F V V x= (1.90) . :

    0( ) (0) ( )

    xdu u x u ddx

    = = + (1.91) ( )u x . F A F, F.

  • 41 . : , . 1, 2007

    ( ) , .(1.45),

    NEA

    = (1.92)

    ( )N N x= , , . .. . :

    0

    ( )( )

    h N xH dxEA x

    = (1.93)

    1.8.2

    x ,

    x BN 1A

    = A (1.94)

    x , :

    N x B1A A

    = = A (1.95)

    :

    0

    0

    (x) dxE

    B x 1 B1 dxEA 2 EA

    =

    = =

    A

    A

    A

    AA

    (1.96)

    , , , , .

  • 42 . : , . 1, 2007

    1.8.3

    , x , . F .

    :

    (1) (2) = = A A A (1.97) :

    (1) (2)(1) (2)

    1 2F N N (EA) (EA) = + = +A AA A

    V v 1 2F (EA) , (EA) (EA) (EA) (Voigt)= = +AA (1.98)

    V(EA) , Voigt38, . (1.98).

    1.8.4

    (1) (2) " . F .

    :

    (1) (2)N N F= = (1.99) :

    38 (.. ). ( ), Voigt.

  • 43 . : , . 1, 2007

    (1) (2)(1) (1)

    1 21 2

    N N(EA) (EA)

    = + = +A A A A A

    1 2R

    1 2

    R 1 2

    F ,(EA)

    1 1 1 (Re uss)(EA) (EA) (EA)

    = = +

    = +

    AA A A A

    A AA A

    (1.100)

    , 1 2= +A A A , R(EA) , Reuss39, . (1.100), .

    : (1) , (2) . .

    T . ( ( ) 22.52 /( )StE N mm C = D . 1.8.5

    , 0R R R(x)= . F. , R R(x)= , . x ,

    N(x)A(x)

    = (1.101)

    39 Reuss.

  • 44 . : , . 1, 2007

    ( )2 20A(x) R (x) R= (1.102)

    . ( 0) = = > (1.103) . (1.101) ,

    N A(x) dN dA = = (1.104)

    N dN dB N 0+ + = (1.105) . (1.104) (1.105)

    dA dB 0 + = (1.106) dB

    dB A(x)dx= (1.107) :

    dA Adx 0 + = dA dxA = (1.108)

    :

  • 45 . : , . 1, 2007

    H 0 , [H] L= > = (1.109)

    :

    dA dxA H

    = (1.110)

    y ln z= , y 1/ z = , dzdyz

    =

    . (1.110)

    dA dx xln A c , c .A H H

    = = + = (1.111)

    lnx cA He e+=

    xH

    0A A e= (1.112) x 0= , :

    20 0, [ ]

    FA A L= = = (1.113)

    H . (1.112) :

    01(0)2 (0)

    A xR RR H + (1.114)

    :

    10.h m= , 0 0.05R m= , 325 /kN m = , 1MPa = , 100F kN=

    : ( ) ( )( )2 2 20(0) 0.2 0.2 0.05m =0.1178R m A m m= = : 2

    0

    100 848.8 0.850.1178

    F kN kPa MPaA m

    = = = = <

  • 46 . : , . 1, 2007

    : 3

    2

    1 10 40.25 /

    kPaH mkN m

    = = =

    20( ) exp 0.12m exp 40x xA x AH m

    = =

    R 0.2m+0.0023 x : 10. 0.225x m R m= =

    1.8.6

    . , ( )N x , . : () ,

    ( )dN n xdx

    = (1.115)

    () ,

    dudx

    = (1.116)

    () -

    N TEA

    = + (1.117)

    (1.115) . ( )N x ( )x . (1.115) (1.117) () :

    ( )( ) ( )d du dEA x n x E Tdx dx dx

    = + (1.118)

  • 47 . : , . 1, 2007

    h , . 40 .

    ( )d x x ,

    ( )1 1 2 xd D D D h= x ,

    ( ) 21 1 24xA D D Dh

    =

    . ,

    ( ) 21 1 2( ) 4xn A x D D Dh

    = =

    , . (1.115),

    0( ) ( ) (0) ( )

    xdN n x N x N n ddx

    = = + , ( 0)A x = . , . (1.118). . (1.118) ,

    40 , . , .

  • 48 . : , . 1, 2007

    ( ) ( )d duE A x n xdx dx =

    ,

    ( ) ( )2 1 21 1 2 1 1 22 2 0D Dx d u du xD D D D D Dh h dx E hdx + =

    ,

    ( ) 21

    1 1 , 0 1Dxh D

    = < = < (1.119)

    uvh

    = (1.120)

    ,

    2

    2 2 0d v dv

    dd + + = (1.121)

    ,

    ( )1

    1h

    E = (1.122)

    . (1.121) ,

    21 2

    1 16

    v C C = + (1.123)

    (1.119) (1.120). , ,

    0 : 0 1 , 0x u v= = = =

    : 0 , 0x h u v = = = = ,

  • 49 . : , . 1, 2007

    ( )2 2 21 1 16v = + + + + (1.124) ( )u x . (1.120) ( )x . (1.116). , Hooke,

    ( )N EA = .

    1) :

    1 20.50 , 0.2 , 3.5D m D m h m= = = , 325 /kN m = 230 /E kN mm= .

    , , . : .

    2) ( 0x = ) 1 50T C= D , ( x h= ) 2 20T C= D

  • 50 . : , . 1, 2007

    1.9

    1) , (2) 2 mm. , ; GPa200= 23cm= . : ! ( ).

    2) (1) (2) . ().

    :

    31 SS = , 42 SS = , 212 SS = ,

    =aS17

    3) . .

    ( )2 PLu 3 33= , ( ) PLv 3u 2 3 3= =

    ( )1 2S 3 3 P3= , ( )2

    2

    3 1 3S P

    2

    =

    35 3 6S P

    3=

  • 51 . : , . 1, 2007

    4) . .

    :

    Fu L= , 0v = , 4F L

    a =

    6) (3). .

    :

    : 1 3 2S S 2 S 2= =

    : u

    v =

    : 3ua

    + = , 2 va = , 1 u v2a

    =

    :

    3 33 3

    S uS (EA)EA a

    = = =

  • 52 . : , . 1, 2007

    2 22 2

    S vS (EA)EA a

    = = =

    1 11 1

    S 1 u vS (EA)EA 2 a

    = = =

    ( ) ( ) ( )u v u 2 v 2 v2 2 2 1 = = = + , ( )2 2 1u 2 2 1+= +

    ( )3 1S (EA)a2 2 1 = + , ( )2 1S (EA)a2 2 1 = + , ( )1 1S (EA)a2 2 = +

    6) . .

    :

    1dS F

    c d= + , 4

    cS Fc d

    = + , 2S F= , 3S F=

  • 53 . : , . 1, 2007

    7) , mm1 . , . , , =200GP 21cm= . , =100GP 22cm= .

    :

    1 2S S= , 3 1S S 2=

    :

    4 5S S= , 3 5S S 2=

    :

    1 2( )

    10 = =

    4 5( )

    4 = =

    ( )3 0.001m ( ) ( ) / 3 = :

    1 2 4 5S S S S 2.377k= = = = , 3S 3.36k=

    1 2 11.8 Pa = = , 4 5 23.6 Pa = = , 3 33.6 Pa =

  • 54 . : , . 1, 2007

    8) ( )0 a < 0.

    21 2= 12 2= . :

    : v 2v = : 1 22S S=

    : 1va

    = , 2 va=

  • 55 . : , . 1, 2007

    : 111

    S = , 22

    2 =S

    : 1 1 21 11 1 1 1 1

    2S S = + = + = +

    +=+=+=

    11

    2

    22

    22

    2

    22

    SS

    : 21 1

    2Sv a = + , 2

    1 1

    Sv a = +

    2 2 1 12

    1 1 1 1

    225

    S S S + = + =

    1 125

    = , 2 215 =

    10) , (1) . (2) (3) 2 3=A A , (1) 1A . () . .

    :

    : 132 SSS == :

    1 11

    1

    Sv = = + = + A

    2 22 3

    2

    Sv / 2 = = = = A

    :

  • 56 . : , . 1, 2007

    12

    1 2

    S ( )2

    = +A

    A A ,

    11 2

    1 2

    S S ( )2

    = = +A

    A A

    11) (1) 1 (0 )= <

  • 57 . : , . 1, 2007

    :

    : 2 10 / 2 0xF S S F+ = + = (1)

    02/0 43 ==+ FSSFy (2)

    : ul

    SSlu

    1

    111

    11

    1

    11

    === (3)

    2 2 22 2

    2 2 2 2

    Sv S vl l

    = = = (4) 3 3 3

    3 33 3 3 3

    Su S ul l

    = = = (5)

    4 4 44 4

    4 4 4 4

    Sv S vl l

    = = = (6)

    (1)+(3)+(5) 3 31 11 3

    02

    Fu ul l

    + + =1

    3 31 1

    1 32Fu

    l l

    = +

    (2)+(4)+(6) 2 2 4 42 4

    02

    Fv vl l

    =1

    2 2 4 4

    2 42Fv

    l l

    = +

    11 1 3

    33 3 1

    12

    lFSl

    = + ,

    14 4 2

    22 2 4

    12

    lFSl

    = + ..

    : ( ) ( )4321 ,,,min,max llllu

  • 58 . : , . 1, 2007

    13) (1) (2) .

    :

    :

    1 230 2 02

    A aWa F S a S a = + + + = 022

    321 =+++ SSFW (1)

    : 2v v = :

    1 11 1

    v S S vh h

    = = = = (2)

    2 22 2

    2v S S v vh h h

    = = = = = (3)

    (1)+(2)+(3): 3 22 02FW v v

    h h + = 3

    2 5F hv W = +

    +=2

    351

    1FWS , 12 2SS =

  • 59 . : , . 1, 2007

    14) , . .

    :

    : 03320 321 =+++= aFaSaSaS 0332 321 =+++ FSSS (1)

    :

    2v v = , 3v v = :

    1 11 1

    v S S vh h

    = = = = (2)

    2 22 2

    2v S S v vh h h

    = = = = = (3)

    2 23 3

    2 62

    v S S v vh h h

    = = = = = (4)

    (1)+(2)+(3)+(4): 2 62 3 3 0v v v Fh h h + = 3

    23Fhv =

    233

    1FS = ,

    236

    2FS = ,

    2318

    3FS =

  • 60 . : , . 1, 2007

    15) . . (1), (2) (3).

    :

    : 2 3 10 2 2 0S a S a F a S a = + + =

    2 3 12 2 0S S F S+ + = (1) :

    v v = , 2v v = :

    1 11 1

    v S S vh h

    = = = = (2)

    2 22 2

    2 2/ 2

    v S S v vh h h

    = = = = = (3)

    3 33 3

    2 4/ 2

    Sv S v vh h h

    = = = = = (4)

    (1)+(2)+(3)+(4): 2 42 2 0v v F vh h h + =

    = 112 lF

    112

    1FS = ,

    114

    2FS = ,

    118

    3FS = ( 1S , 2S 3S )

  • 61 . : , . 1, 2007

    16) 2 . . (1) (2) 2. . .

    :

    : 1 2 1 20 2 0 2 0S b S b S S = + = + = (1)

    : 2v v = :

    1 11 12 2

    v S S vl l

    = = + = = (2)

    2 22 22 2 2 2

    v S S vl l

    = = + = + = (3)

    (1)+(2)+(3): 2 2 2 2 02

    v vl l

    = 9 105 02 9v lvl

    = =

    == 94

    95

    11 SS

    == 922

    920

    22 SS

    ( =1S , =2S , : =2200 1 mmCC )

  • 62 . : , . 1, 2007

    17) . , . , 2mm . . GPa200= . 23cm 22cm . .

    :

    : 1 20 8 5 100 4 20 8 0S m S m m m = + + + =

    31 28 5 (400 160) 10 0S S+ + + = 31 28 5 560 10 0S S + + = (1)

    : == uu

    uu

    8558 (2)

    : ( )muu ,, ( ) , 21 SS 1 1 1

    1 4 2 9 214 2 10 200 10 /u S Sm m m

    = = = =

    7117 104 4 10

    u S S u = = (3)

  • 63 . : , . 1, 2007

    32 2 2

    2 4 2 9 22

    2 101 3 10 200 10 /

    u m S Sm m m

    = = = =

    ( )3 72 2 10 6 10S u = (4) (3)+(2): 8

    5u u = , 71 8 105S u= (5)

    (1)+(4)+(5):

    ( )7 3 7 488 10 5 2 10 6 10 56 10 05 u u + + = 37.3 10 7.3u m mm = =3

    1 117 10 117S k = = , 3 72 (2 7.3) 10 6 10 318S k= =

    18) , 500T C = D , . . . : ) GPa100= , Ca 06 /10= ,

    220cm= . ) , , : GPa200= , 210cm= . , : GPa100= , 220cm= . : Ca 06 /10= .

    :

    . .

    : 41 SS = , 222 11

    2 SSS ==

  • 64 . : , . 1, 2007

    : 53 SS = , 222 33

    2 SSS ==

    =

    ===212

    5431

    SS

    SSSS (1)

    :

    1 11 4

    / 22.5 2

    S vm

    = = + = 1 5vS = ( ) v m (2)

    3 33 5

    / 21 2

    S vm

    = = + =

    = 53S ( ) v m (3)

    2 22 1.5

    S v vm

    += + = 2 1.5v vS + = (4)

    (1)+(2)+(4): 21.5 5

    v v v + = ( )1.5 5 2 0v v v + + =

    ( ) =++ 5.7525 (5) (1)+(2)+(3):

    5 2v v = 2 5v v = (6)

    (5)+(6): ( )5 2 2 7.5v v a + + =

    637.5 7.5 10 500 0.411 10 0.411

    7 2 7 2av m mm

    = = = =+ +

    30.164 10 0.164v m mm = = :

    34 9

    1 3 4 5 20.411 1010 10 200 10 16.44

    5mS S S S m k

    m

    = = = = =

    = kS 2.232

  • 65 . : , . 1, 2007

    v b+

    2bu +

    v b

    2bu +

    v b

    2bu

    19) , , . . (2) T . .

    :

    3: , ,u v . :

    :

    :

    :

  • 66 . : , . 1, 2007

    v b

    2bu

    :

    :

    1: 1 11/ 2

    2Su b u

    b b += = + = = (1)

    2: 2 22 2 2 2Su b u

    b b = = = + = + (2)

    3: 3 331 / 2 3

    2 42 2 2Sv b u b u v

    bb + = + = = = (3)

    4: 4 441 / 2 3

    2 42 2 2Sv b u b v u

    bb + = = = = (4)

    :

    341 1 4 30 : 0 22 2x

    SSF S S S S+ = + = + (5)

    1S

    2S

    2b

    y

  • 67 . : , . 1, 2007

    3 42 2 3 40 : 0 2 02 2y

    S SF S S S S+ = = + + = (6)

    1 2 1 20 : 2 0 52 2b bS S b S S = + + = = (7)

    (1)+(2)+(3): 3 22 2S S= (5)

    24 23 SS = (6) (5), (6), (7) (1), (2), (3) (4):

    52 2 2

    u vb b

    + =

    3 2 22 4 2 2

    v u vb b

    + =

    3 3 22 4 2 2

    v u vb b

    =

    :

    u Xab= , v Ya

    b= , Za = ZYX ,, :

    5 3 52

    X Y Z+ + =

    ( ) 31 2 2 2 2 4 22X Y Z + + + = ( ) 31 3 2 3 2 6 22X Y Z + + + =

  • 68 . : , . 1, 2007