??????é“?é’‰?‰?????????????????·??¨???????
é“?é’‰??????è????—????’????????‰???????????‰??¤????????”¨??¨è?”????????¤??§é???????????????¤–?????????????¤§?°??????‰(??????F)???è???–???‘?????????????”¨??????è·????è?‘????????????è??????”¨???é?¨??????????????????????”¨??????è????????é??m-m(?§°????‰????é??)??‘?”???????é”???¨???è???§????????§°????‰?????????????
: H; d- [3 M& x0 p2 q: j
???????‰???????????”¨è????—
?‰????é??????????…???????”¨???é??????±???—????°?é“?é’‰????????°????‰????é????????????”±???è????????
. W9 F; X2 H: o: H7 L# ~& N
% u- T2 k& c% j6 \! J e
???????‰????é??????????¨???????¤–???F?¤§?°??????‰????–???‘???????????…???

????§°????‰????(???c)???

?¨????é?????????‰?????????????é??????”¨??????????”±???é????????????¤?????‰???”???

?‰???????(???d)??? ?‰????é?????????‰???”???????????…???è??????¤???????????”¨è????—??????è???‰???”???

??¨?‰????é???????????????????????
??????

????‰????é??é???§????è??é“?é’‰?????????d??????

??????é“?é’‰?????‘?”??‰?????????????è???±?
è???°±???é“?é’‰????‰?????????????????????????

???é“?é’‰??????è???????”??????
2 E* M" ?6 z- a9 P. J
" x) a& Y5 U$ ?# P5 A, S8 Z??? ???????‰??¤?????·????é’?????????????t=lOmm????…??‰???????é????”??????

=300MPa???è???”¨???????°?é’????????????????d=25mm?????”???é—?é??è???¤??¤§???????‰????F?
è§?????‰????é???°±???é’????è??????¤???????????????±??“??§é??(???b)????…?é???§????
?????”?‰?é??è?????????‰??????”???
+ k/ [: {$ Z, }4 q
??‰?????¤??????????”¨è????—
????”¨è????—??????è????¤?????”???????????°????????¨??¤???é???????????
?‰?????????¤??????????????????

???6-12??‰
??????

??????è????¤?????”?????????????”±é??è????¤?????????è??é????—??°??????é????¤?????”???

é?¤?????‰?…¨?????°n??—??°???????§?????–????è???”¨??¤?????”????????¨??‰?…??‰????????????—?????????é’????è??è¨????é???????–??????è???????”???

???1.7???2.0??????
?…??????¤???é??é???§?

???è????—???è???????????è§?é???????…???è??????????“???é?…??¤???é????????é???—??????¤???é??é???§???????è§?é??é???§??????“??—???é?????????????±???é???—??????¨???é?…è????—???????????‰??¤???é?????????????±é???§?è????—???(???e)
$ k, w" f% V0 G! s% e4 P
( \ W6 b" Z% b: | @; }9 s??????é“??????????è????—
é“???????è????“è?”??????é”?é’‰è?”?????‰é??????·??¨????????”¨???è?”???????????????è???±?è?”??????????????…è??è????—è?”?????????????§??????????é?????è??è?????è??è?”?????????????¤?é?¨???è??è????????è????—???
????????‰??????é“????????¤?
?????????a??‰?‰??¤????é“????????¤???????è????‰??‰?§????????????????(1)é“?é’‰????¨????é???‰??–?????§°????‰?????????????(2)é“?é’‰????????”????????’??¤???è????¨é“?é’‰??±è?¨é???’???”?????±é??????±?é?¨è???????…??‘?”????è‘—?????‘??§??????????§°?????¤????????????(3)?????¨é’‰??”???????”±??????é???‰???±è??è????‰?–?????§°?????‰?–???????????????¤?????¨é“??????????è????—?????????è????‰?§????è?????????????…????????”è??è?‘???
/ B: ?3 z# m5 _# F8 J* J1 m
. J8 H' ]9 B; `/ r/ N q2 K??¨???(a)?‰??¤????è?”?????…?????????é“?é’‰?????—?????…????????? (b)?‰??¤??????”?”¨???é????????????±???—é“?é’‰???é—??¨????é???????…???????‰???????è???¨????é???°±????‰????é?????é“?é’‰?°????è?????è???¨????é????‘?”??‰??????????????”±é“?é’‰??????é?¨??–??????é?¨??????è???–??¨?????±???—
??¨è?”?????????????”¨è????—?????????????‰????é?????????????”???????????????????????¤????‰????é?????????????‰?????”??????
??????????‰????é??é???§????è??é“?é’‰?????????d?????? ??????é“?é’‰?????‘?”??‰?????????????è???±?
??¨è???§???????è?”?????????é“?é’‰????‰????é???????‰???????????…?§°???????‰????
é“?é’‰??±é???’?????????”???é??????°?????????’?????§è????§?”???¤??????

??????è????¨?????’?????§???è???????…???è?·??¤?????”???

??¤?????????????”±é“?é’‰??????é?¨??–??????é?¨?????–?????—é’??????????è???–??¨??±???—
??¤?????”?????????é?…????????…?????”è???¤????????????????é“?é’‰??–??”?????????é??é???§????é“?é’‰??????????????????????§??????????????????¤???é???§?

??????è?????é??????????????????????¤?????”??????
è??é“?é’‰????????????d??????????????????

??????

?????????é“?é’‰??–??”????????‘?”???¤????????????è???±?
è???°±???é“?????????¤??????????????????????????????è????¤?????”?????????????”±é??è????¤?????????è??é????—??°??????é????¤?????”???é?¤?????‰?…¨?????°n??—??°???
??¨????”¨è????—????????????è?????é???????‰??”?????????????????????????????¤???è????—???è?????é??????????‰??‰??”??????
??????

???????????—??‰é??é???§????è??é“?é’‰?????????d??????????????????????????????b??????

???????????¨è?????é???????‘?”???‰?–??????????è???±?
è???°±???é“?????????‰????????????????????????

????????????è????‰??”??????
??????è??é“????????¤???????????????”????—????è??????????????????????‰??????????????????è????‰????????????????????????é“????????¤?????????????è??è??é“?é’‰???????’?è????—???è??è?·è?????
??????(a)?‰??¤????é“????????¤?????????¨????????????????????—??–???????·???????????”¨??????é“?é’‰????°????????????¤??—é’????è?”???è?·????????¤è??è?”??????é’?????§°??????????????¤??????é??è??é“?é’‰?????–????????’???é?’????”¨??????
9 M0 r! S/ Q5 z( D7 T
+ {! A3 \/ A' ^- R
??¨????”¨è????—??????????????¤????‰????é?????????‰?????????‰????????????F/2?????????è????????é“?é’‰?????—?????…?????????6-39 (c)?‰??¤???????????‰????é?????????????‰?????”?????????????????‰?????????
????????????????‰????é??é???§????
??¨è???§???????è?”????????????????????????

é??????°??????¤??–?????????

????’???????

??????è??é??è????????é“?é’‰???????????±é?????????????”???é—?????????’??¤??????é“?é’‰????????±é?????????????”???é—?????????’??¤?????????????????¤????????”????????‰??¤?????”??????
- X* _2 J2 H! i& m9 S7 {; y1 x
???????????¤???é??é???§????
??¨è???§?è?”??????????”±????????…???é??è????—???????????‰??????????????????è??é’‰??”?‰???±??????è??é“?é’‰??????????¨????é???????±é?????é?????è?????é????????è????????????????‰??‰??”??????
?????????????????—??‰é?????é???§????
????????????????¤??????—?????–??????????¤?????????—????????????é“?é’‰è?…è???????????è???§?????¤??°±?§°???é“?é’‰??¤????¤????????????¤?§???…??????1??‰?¤–???é??è??é“?é’‰??¤?????????2??‰?¤–??????é??è??é“?é’‰??¤???????????¨è??é????…???????¤–???é??è??é“?é’‰??¤???????????…??????
?????–??????é“?é’‰????‰??????????è????—?????–??????é“?é’‰??±é????–?????”???é???????¤?????????è????—????…·??“?–???????????…§???è?°??????é“??????…???è??è?????
& v; l7 p7 B* }$ P8 r4 U. Q
2 {' T! E% q$ \2 D" G" I1 J# ~??? ??? (a)?‰??¤??????????é“?????¤???????è????‰3???é“?é’‰?????—è????‘??‰???F???130 kN????”¨????·???????????????–??????b=110mm????????????=10mm?????–??????=7mm???é“?é’‰??????d=17mm???????–???????è????”????????????=120 MPa???=160MPa, =300MPa???è????????é“?????¤?????????????
" m: n( F" z+ ~4 g) n- _7 y9 n) w
/ n N+ c& o7 _# F* L' Q7 W
è§?: ?”±??????????‰???—?¤–???Fé??è??é“?é’‰??¤??????,??…??????é“?é’‰??—????????‰,??????F???3??? ?”±????????????é“?é’‰??—????‰????é“?é’‰????‰???????????????????
?°??·??????°??????????????—
?‰????é“?é’‰????‰?????????????è???¤????????”±????????…é??????????????(??–é“?é’‰)???é—?????????¤???????????????????????????
?°??·??????°??????????????—

?‰??????¤??????????????????è????????
???????????‰??????????????????

?????????è???????????è?????????????????(b)?‰??¤?????”±??????è§??????¨l-1???é????????è?????

?????????è????????é“?é’‰??”?‰???±???

??????2-2???é?????è?????

??????è????¤???é’‰??”?‰???±???

????—???????è§???¤?–??“????????????±é?????é???????…??”?????¤??????é??é??è??è????‰???????????????????”±?·??????°???????±???—è????¤????¨????é??????????‰?????”??????
?‰???????????????‰??????????????????è????????