F) bu yerda
a = S -c o s 4 5 ° =
S —
;
y = — \ A C = S bo M g a n lig id a n
2
G AS = — S
(a)
2
G (Jm umlashgan G u k q onuniga k o ‘ ra n is b iy uzayish q u yid ag ich a y o z ila d i:
AS cr. a ,
s, - —
= — - u — , 1
S E E cr, = г va cr3 =
- г e k a n lig in i e’ tib o rg a olsak, uzayish
(l + jj ) t AS = ±— ^ — S (b ) boMadi.
E (a) va (b ) ifo d a la m in g chap to m o n la ri teng boMgani u ch u n o ‘ n g to m o n -
la r ham teng boMadi:
G = 2 ( l + / / ) '
(5 -5)
B u fo rm u la d a g i c h o ‘ z ilis h (s iq ilis h ) e la s tik lik m o d u li E v a Puasson k o
e ffits ie n ti ц ta jrib a yoM i b ila n a n iq la n a d i. B u la r o rq a li s iljis h d a g i e la s tik lik
m o d u lin i aniqlasa boMadi.
1
3
A g a r
Ц = — boMsa,
G - —E boMadi.
j
8
5.2. Sof siljishda ruxsat etilgan kuchlanishlar R u x s a t e tilg a n k u c h la n is h n i ta n la sh m asalasi s iljis h d a s iq ilis h va
ch o ‘ zilishdagiga nisbatan ancha m urakkab. C hunki tajribalarda boshqa x il de-
form atsiyalardan x o li boMgan s o f siljis h holatiga erishish ju d a q iy in . Shu saba
b li siljishdagi ruxsat etilgan kuchlanishlar nazariy yoM lar b ilan belgilanadi.
T e k is k u c h la n is h h o la tid a u ch ta bosh ku ch la n ish d a n b ir i n o lg a teng
boMadi (5 .5 -ra sm ). Shunga k o ‘ ra s o f s iljis h d a
cr, = r ,
cr2 = 0,
cr3 =
