Eski va yangi oMcham birliklari 1 9 6 0 -y ild a H a lq a ro o M c h o v la r sistem asi j o r iy e tild i. B u sistem a S I (S i)
sistem asi deb a ta la d i. B u sistem aga k o ‘ ra asosiy o ‘ Ic h o v uchun 1kg massa
q ab u l q ilin d i va k u c h o ‘ lc h o v i uchun undan k e lib c h iq u v c h i m iq d o r qabul
q ilin d i.
SI s is te m a s id a k u c h n in g o ‘ lc h o v b i r l i g i q i l i b
1
k g m assaga
lm /s - tezla n ish b e ru v c h i kuch q a b u l q ilin a d i. B u oMcham « N ’ y u to n » deb
a ta la d i va N h a rfi b ila n b e lg ila n a d i.
K u c h o ‘ lc h o v b irlig id a eski (M K G S S ) va ya n g i (S I) sistem alar orasi-
dagi bogManish q u y id a g ic h a ifo d a la n a d i:
1 k g = 9 ,8 0 6 6 5 N * 10 N ,
1 N = 0 ,1 0 1 9 7 k g = 10-' kg,
1 x = 104 N ,
1 N = 10-6 M N , dem ak, I t = IO '2 M N , 1 M N = 106 N ,
bunda M N - m e g a N ’ y u to n deb o ‘ q ila d i.
M assa o ‘ lc h o v i q u y id a g ic h a boM adi:
1 k g » 0,1 k g -s 2/m ,
c h u n k i 1 kg -sV m = 9,81 « 10 N .
B o s im (k u c h la n is h ) y a n g i sistem ada q u y id a g ic h a ifo d a la n a d i:
1 k g / sm 2 = 10 N /s m 2 = 105 N /m 2 = 10_l M N /m 2;
1 N /s m 2 = 10 '1 k g / sm 2 = 10 '2 M N /m 2.
Ish (e n e rg iy a ) ifo d a s i:
I kg m = 10 N m = IO '5 M N m ;
1 N m = 10’ 1 k g m = 10"1 tm .
SI sistem asida ish b ir lig i u ch u n IN k u c h n i l m y o ‘ ld a bajargan ish i
q a b u l q ilin g a n . B u n i «Joul» deb a ta la d i va J h a rfi b ila n b e lg ila n a d i.
M U N D A R I J A
I BOB. KIRISH
1.1. M ateriallar q arsh ilig i fan i v a z if a la r i.............................................................................10
1.2. M ateriallar qarsh ilig i fa n in in g rivojlanish y o ‘l l a r i ................................................. 13
1.3. Inshootlar va ularning h iso b lash sxem alari. T a y a n c h la r...................................... 16
1.4. Y uklar ta s n if l........................................................................................................................19
1.5. Ichki kuchlar. K esish usuli. K u c h la n is h la r............................................................... 22
1.6. K onstruksiyalami hisoblashda m atritsalar nazariyasi va a m a liy o ti........................ 24
1.6.1. M atritsalar haq id a t u s h u n c h a ...................................................................................... 24
1.6.2. Materiallar qarshiligi m asalalarida uchraydigan matritsa v a v e k to rla r.................. 27
1.6.3. M atritsalar ustidagi a m a l l a r .........................................................................................30
II BOB. CHO‘ZILISH VA SIQILISH
2.1. C h o 'zilish v a siqilishda kuchlanish v a deform atsiyalar. G uk q o n u n i................... 35
2.2. S en-V enan p rinsipi h a q id a ............................................................................................... 40
2 .3. M ateriallam i c h o 'z ilis h g a s i n a s h ................................................................................... 41
2 .4. C h o ‘zilish diagram m asi va u n in g x arakterli n u q ta l a r i .......................................... 42
2.5. M ateriallarni siq ilish g a s i n a s h ........................................................................................46
2.6. M ateriallam in g qattiqligini aniqlash ............................................................................48
2.7. K u chlanishlar k o n se n tra tsiy a si........................................................................................49
2.8. R uxsat etilgan kuchlanishlar. K esim ta n la s h ............................................................ 50
2.9. X ususiy o g ’irlikni h iso b g a o l i s h ...................................................................................59
2 .1 0 . C h o 'z ilish v a siq ilish d a statik noaniq m a s a la la r.................................................. 63
2 .11. T em p eratu ra (harorat) o ‘zgarishidan hosil boMadigan
k u c h la n is h la r................................................................................................................................. 66
2.12. Sterjenlarni ch o ‘ziIish v a siq ilish g a hisoblashni o ‘rgatuvchi
k o m p y u ter tex n o lo g iy a si............................................................................................................68
III BOB. KESIM YUZALARINING GEOMETRIK
TAVSIFLARI
3.1. G eom etrik ta v s ifla r............................................................................................................. 75
3.2. Parallel o ‘qlarga nisb atan inersiya m om entlari o rasidagi b o gM anish...............81
3.3. O 'q la r burilganda inersiya m om entlari orasidagi b o g 'la n is h .............................. 82
3 .4. K o 'n d a la n g kesim lardagi asosiy o ‘q lar, bosh in ersiy a o ‘qlari v a
bosh inersiya m o m e n tla r i..........................................................................................................83
3 .5. In ersiy a ellipsi v a u n in g xossalari ............................................................................... 86
3 .6. T ek is y u zala rn in g geo m etrik tav siflarin i k o m p y u terd a
h iso b la sh a lg o r itm i...................................................................................................................... 86