วิเคราะห์โครงสร้าง บทที่ 7 tt

r

al

II·· ., .. ­ ....

- ~j. __ l ••:f...... , .. .AwL _aA .. ~",A". +tl._.1\

2

p VY Plane of

I- i . f-dx I

Elastic curve symmetry
(a)
z ---ttl

Beam cross section

df1 ac
2 a _}

-----f'- ­

1--·- d x - - l · 1 Neutral
surface

(b) (c)

.

11Hl 7.1
'U

v •v

Vjill1 ru lfll 'W l''lJ Ul '11 'l!f1 fU~ Yll1~ 1 ~~~~ Q l f1 n'lJ!!f1'W f1'W 6ri 1~!!(;'I~t) cjl'W 1~'W l'lJ
'U 'U

.. ~

(l':lJ:lJwn6]Jt)\l'l1t!l~~fll'W (Plane of symmetry of its cross section) ~~tllcVi 7.1 (a) ~'WNl

6]Jt)~Uf1'W(l'~!Vl'W ill flll~f1l1!irtltllil~!~(Jf1illl1\lf1l11f1\l~1~~t1~'W(Elastic curve)

11• v

!~ C)~(l'il b1'~J f1l1 ~h~ rw t)!1'W!9f(J ~6]J t) ~ 1f{\l f1l~ 1f1 \l ~1~~ '11 cj'W !~ l il~Vj il n ru 19f'W -ffl'W
'U q
v•

!~f11 dx 6]Jt)~fll'W 9f'W~h'Wvhn~f1l~!irtltllUb1'~\l1'Wt1l7.l(a)