chuong 1 công nghệ chế tạo máy

BI GING CNG NGH CH TO MY

H ni, 1/2015

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B mn Cng ngh ch to my

Vin C kh - HBKHN

T1

Sch gio trnh

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B mn Cng ngh Ch to my Vin C kh BKHN

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Gio trnh Cng Ngh Ch To My

Chng 1. Nhng khi nim c bn

Chng 2. Cht lng b mt gia cng

Chng 3. chnh xc gia cng

Chng 4. Chun

Chng 5. Lng d gia cng

Chng 6. Tnh cng ngh trong kt cu

Chng 7. Chn phi v gia cng c/b phi

Chng 8. Cc phng php gia cng ct gt

Chng 9. Gia cng tinh bng b/dng do

Chng 10. Cc phng php gia cng khc

Chng 11. Gi thnh sn phm

Chng 12. Tiu chun ha qu trnh c/ngh

Chng 13. Ti u ha qu trnh ct gt

Chng 14. Phng php thit k QTCN

Chng 15. QTCN ch to cc chi tit hp

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Chng 16. QTCN ch to cc chi tit cng

Chng 17. QTCN ch to cc chi tit trc

Chng 18. QTCN ch to cc chi tit bc

Chng 19. QTCN ch to bnh rng

Chng 20. Nng sut lao ng

Chng 21. Cng ngh lp rp

Chng 22. m bo cht lng sn phm

Chng 23. Hng pht trin ca CN CTM

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Ni dung mn hc



Chng 3. chnh xc gia cng

Chng 4. Chun

Chng 5. Cc phng php gia cng ct gt

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Phn m u

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Chu trnh thit k & pht trin sn phm


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I. Qu trnh SX v qu trnh CN

1. Qu trnh sn xut

2. Qu trnh cng ngh

3. Ch lm vic

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1. Qu trnh sn xut

Qu trnh SX : QT con ngi tc ng vo ti nguyn, thin nhin to thnh sn phm

Theo ngha rng: QTSX bt u t khu khai qung, luyn kim, ch to phi, gia cng c, gia cng nhit, lp rp, sn, chy th, ng gi

Theo ngha hp: trong mt nh my SX c kh th QTSX khng bao gm khai qung v luyn kim, hoc trong nh my c kh ch chuyn ch to phi, ring lp rp hoc ng gi

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2. Qa trnh cng ngh

L mt phn ca QTSX trc tip lm thay i trng thi v tnh cht ca i tng SX (thay i kch thc, hnh dng hnh hc v v tr tng quan). V d:

QTCN gia cng c

QTCN nhit luyn

QTCN lp rp

QTCN ch to phi (c, hn, dp, cn)

Xc nh QTCN hp l ri ghi thnh vn kin CN th vn kin c gi l qui trnh CN

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3. Ch lm vic

L mt phn ca phn xng SX c dng thc hin cng vic bng mt hoc mt s cng nhn.

Ti ch lm vic c b tr cc loi dng c, g, my ct, thit b nng h, gi phi, chi tit hoc n v lp rp

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II. Thnh phn SX ca nh my CTM (1)

Cc phn xng chun b phi (phn xng c, phn xng rn dp, phn xng hn)

Phn xng gia cng (g/c c, nhit luyn, dp ngui, g/c g, m, lp rp, sn)

Cc phn xng ph (p/x dng c, sa cha in, ch to khun mu, p/x th nghim, ch th)

Cc kho cha (vt liu, dng c, khun mu, nhin liu, sn phm)

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II. Thnh phn SX ca nh my CTM (2)

Cc trm cung cp nng lng (in, nhit, kh nn, trm cung cp nc)

Cc c cu vn chuyn (xe nng h, cn cu, ng ray vn chuyn trong ni b nh my)

Cc thit b v sinh-k thut (t/b si m, thng gi, ng ng cp nc, h thng cng rnh)

Cc b phn chung ca nh my (phng CN, phng TK, o lng, cc vn phng, nh n, trm x, h thng thng tin lin lc)

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III. Thnh phn ca qui trnh cng ngh

1. Nguyn cng

2. G

3. V tr

4. Bc

5. ng chuyn dao

6. ng tc

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1. Nguyn cng

L mt phn QTCN c hon thnh lin tc ti mt ch lm vic do mt hay nhm cng nhn thc hin g/c mt hoc mt s chi tit cng lc. Nu khng c cng nhn phc v th gi l n/c TH. V d, kp A g/c B & C, sau quay u kp C g/c A th ta c 1 n/c. Nhng nu kp A g/c c lot chi tit ri quay u g/c c lot thi ta c 2 n/c. Hoc kp A g/c B,C trn mt my ri chuyn sang my khc g/c A th ta c 2 n/c. Tin ng knh ngoi v phay rnh then l 2 n/c

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2. G

L mt phn ca QTCN c hon thnh trong mt ln g t mt hoc nhiu chi tit cng lc. V d, tin u B,C ri quay u tin u A l 2 ln g t

Mt n/c c th c mt hoc nhiu ln g t

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3. V tr (1)

V tr l mt phn ca n/c c xc nh bi mt v tr tng quan gia chi tit v my hoc gia chi tit v g. V d, tin B,C ri quay u tin A l 2 v tr khc nhau

Mt n/c c th c mt hoc nhiu v tr

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3. V tr (2)

Chi tit c g trn g quay c 4 v tr khc nhau

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4. Bc

L mt phn ca n/c g/c mt b mt (hoc nhiu b mt) bng mt dao hoc nhiu dao vi ch ct khng thay i. Nu thay i b mt g/c hoc ch ct ta s chuyn sang bc khc. V d, tin 3 on A,B,C l 3 bc (khi dng mt dao), tin 4 mt u D,E,F,G l 4 bc. Sau khi tin, thay ch ct ta s c bc khc

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5. ng chuyn dao

L mt phn ca bc ht i mt lng kim loi c cng ch ct v bng cng mt dao

V d: tin cc on A,B,C ta phi dng mt dao vi cng ch ct ct nhiu ln, mi ln ct l mt ng chuyn dao

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6. ng tc

ng tc l hnh ng ca ngi cng nhn K my khi g/c hoc khi lp rp

V d: bm nt, quay dao, y ng, thay i ch ctCn i vi lp tp th ly chi tit, lau sch chi tit, bi m ln chi tit, cm cl, sit ai c

Vic phn chia thnh ng tc rt cn thit nh mc thi gian g/c v lp rp, ng thi nghin cu nng sut lao ng v t ng ha nguyn cng

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IV. Sn lng & sn lng hng nm

Sn lng l s lng my, chi tit hoc phi c ch to ra trong mt n v thi gian

Sn lng hng nm ca chi tit c xc nh theo cng thc:

N = N1.m (1 + /100)

y: N s chi tit c SX trong mt nm

N1 s sn phm (s my) trong mt nm

m - s chi tit trong mt sn phm (mt my)

s chi tit c ch to d phng (5%)

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V. Cc dng sn xut

1. Sn xut n chic

2. Sn xut hng lot

3. Sn xut hng khi

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1. Sn xut n chic (1)

L SX c s lng SP hng nm rt t (mt n vi chc chic), SP khng n nh do chng loi nhiu, chu k ch to li khng xc nh c. c im:

Ti mt ch lm vic g/c nhiu loi chi tit khc nhau

G/c v lp rp thc hin theo tin trnh CN

S dng TB v DC vn nng. My c b tr theo tng loi

S dng g, dng c o vn nng

Khng thc hin c vic lp ln hon ton

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1. Sn xut n chic (2)

Cng nhn c trnh tay ngh cao

Nng sut lao ng thp, gi thnh sn phm cao

V d: dng SX n chic l ch to cc my hng nng, cc SP ch th hoc ch to theo n t hng

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2. Sn xut hng lot (1)

L dng SX c SP hng nm khng qu t, SP c ch to theo tng lot vi chu k xc nh. c im:

Ti cc ch lm vic c thc hin mt s n/c c chu k lp li n nh

S dng cc my vn nng v c/d

Cc my c b tr theo dy chuyn CN

S dng nhiu d/c v /g chuyn dng

m bo nguyn tc lp ln hon ton

Cng nhn c trnh trung bnh

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2. Sn xut hng lot (2)

Ty theo sn lng v mc n nh ca SP, ngi ta chia SX HL ra:

SX HL nh (gn vi SX C)

SX HL va

SX HL ln (gn vi SX hng khi)

V d SX HL: ch to my cng c, my nng nghip

Trong SX HL va c th t chc theo dy chuyn SX linh hot (sau mt thi gian c th g/c lot chi tit mi)

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3. Sn xut hng khi (1)

L dng SX c sn lng rt ln, SP n nh lu di (1-5 nm). c im:

Ti mt ch lm vic thc hin mt n/c no

Cc my c b tr theo dy chuyn cht ch

S dng nhiu my t hp, my t ng, my chuyn dng, ng dy t ng

G/c v lp rp c thc hin theo dy chuyn

S dng /g, dng c o chuyn dng

m bo nguyn tc lp ln hon ton

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3. Sn xut hng khi (2)

Nng sut lao ng cao, gi thnh SP h

Cng nhn c trnh tay ngh khng cao nhng th iu chnh my li c trnh tay ngh cao

V d SX h/khi: ch to t, my ko, vng bi, bnh rng, c vt, cc thit b o lng

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VI. Nhp sn xut (1)

Trong SX HL ln v HK thng s sng PP SX dy chuyn (c g/c c v lp rp). Theo PP ny th cc my c b tr theo th t cc n/c. S my (s v tr) v nng sut ca my phi tnh ton sao cho ng b (khng b nh n gia cc n/c)

Mun dy chuyn SX ng b phi tun theo nhp SX

Nhp SX l thi gian lp li chu k gia cng

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VI. Nhp sn xut (2)

Cng thc tnh nhp sn xut t: t = F/q

F-thi gan lm vic theo ca, thng, nm (ph)

q s lng SP hoc chi tit c ch to ra trong thi gian F

V d, mt ca lm vic: 8x60 ph= 480 pht, g/c c 60 chi tit, vy nhp t s l:

t = 480/60 =8 pht hoc l bi s ca 8

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VII. Xc nh dng sn xut

Khi c sn lng hng nm N, ta xc inh khi lng ca chi tit Q: Q = V. y: V l th tch ca chi tit (dm3 ), l khi lng ring (thp l 7,852kg/dm3, gang l 7,2 kg/dm3, nhm l 2,7 kg/dm3 v ng l 8,72 kg/dm3. Khi c N & Q ta dng bng sau xc nh dng sn xut

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VIII. Tp trung v phn tn nguyn cng

1. Phng php tp trung nguyn cng

2. Phng php phn tn nguyn cng

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1. P/php tp trung nguyn cng (1)

Tp trung nguyn cng l b tr nhiu bc CN vo mt n/c v thc hin trn mt my

Thng TT nguyn cng c thc hin i vi cc bc CN gn ging nhau nh khoan, khot, doa, ct ren hoc tin ngoi, tin trong

PP tp trung nguyn cng ng dng cho cc chi tit phc tp c nhiu b mt g/c

p dng PP ny phi dng nhiu my t hp, my nhiu trc chnh (g/c c tin hnh tun t trn tng trc chnh v ng thi trn nhiu v tr khc nhau)

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1. PP tp trung nguyn cng (2)

Trong trng hp ny thi gian g/c chi tit bng thi gian g/c trn mt trc chnh

Nng sut g/c tng nh g/c song song v s trng hp ca thi gian my

T/gian ph bng T/gian quay bn my i mt v tr

PP cn dng cc my nhiu dao g/c chi tit

PP tp trung nguyn cng cho php nng cao h s s dng mt bng sn xut

Nhc im ca PP: iu chnh my phc tp

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2. PP phn tn nguyn cng

PP phn tn n/c: chia QTCN ra nhiu n/c nh, mi n/c c thc hin trn mt my

S dng cc my thng thng, cc dng c tiu chun v trang b CN n gin

PP c tnh linh hot cao (chuyn i i tng gia cng rt nhanh chng)

Hin nay, trong CTM thng p dng PP TT n/c trn c s TH SX

PP PT n/c ch p dng qui m SX ln nu trnh SX km nhn t gc k thut SX

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I. Khi nim

Cht lng b mt g/c c nh gi bng 2 yu t c trng:

Tnh cht c l ca lp kim loi b mt (mc bin cng, chiu su bin cng v ng sut d)

nhm b mt

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II. Cc dng b mt gia cng

1- sng v nhm

2- sng v nhm va phi

3,4- b mt phng v nhm thp

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III. nhm dc v nhm ngang

a) nhm dc

b) nhm ngang

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IV. Cc yu t nh hng CL b mt

Tnh cht ca vt liu gia cng

PP gia cng (tin, bo, phay, mi)

Ch ct (S,V,t)

cng vng ca h thng cng ngh

Thng s hnh hc ca dao

Dung dch trn ngui

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V. nhm b mt (1)

nhm b mt ( nhp nh t vi) l tp hp tt c nhng b li, lm vi bc cc nh

nh gi nhm ta v ng trung bnh. ng trung bnh c v sao cho tng din tch (phn gch ng) t hai pha bng nhau

Chiu di chun l l chiu di dng nh gi cc thng s ca nhm

Ra sai lch bnh phng trung bnh cng ca cc gi tr chiu cao h tnh t ng trung bnh trong phm vi chiu di chun l

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V. nhm b mt (2)

Ra c xc nh:

l- chiu di chun, h- tung profin o c t ng trung bnh

Rz c xc nh theo cng thc:

[(H1+H3+H5+H7+H9) - (H2+H4+H6+H8+H10)]/5

Sm- bc nhp nh theo ng trung bnh (gi tr trung bnh cng ca cc bc nhp nh)

S bc nhp nh theo nh (gi tr trung bnh cng ca cc bc nhp nh theo nh)

n

l i

1a

0

h1

R hdll n

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V. nhm b mt (3)

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VI. ng cong ca phn vt liu

Chiu di ca phn vt liu v tr no l tng chiu di ca phn kim loi i qua cc im ca nhm

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VII. Cp nhm (1)

Tiu chun nh nc qui nh: nhm chia ra 14 cp. Cp 1 c nhm cao nht, cp 14 c nhm thp nht

Tr s Ra c cho khi yu cu nhm b mt t cp 6 n cp 12

Tr s RZ c ghi trn bn v nu yu cu nhm trong phm vi t cp 1 n cp 5 hoc cp 13 v 14 (RZ = 0,08~0,05 m)

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VII.Cp nhm (2)

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VIII. /hng ca /nhm n TCSD ca c/tit

nhm c nh hng n:

1. mn U ca chi tit

2. Qu trnh n mn ha hc trn b mt

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1. /hng ca Ra n /mn U ca chi tit (1)

Ma st v mn ca chi tit my ph thuc v chiu cao v hnh dng ca nhm b mt v phng ca vt g/c

Cc im 01 v 02 ng vi mn ban u nh nht ca cc b mt tip xc

Ta thy: trong iu kin lm vic nng ng cong 2 dch chuyn v pha trn v bn phi ng vi nhm ti u (02)

ng cong 1: iu kin lm vic nh

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1. /hng ca Ra n /mn U ca chi tit (2)

mn ban u c th san phng 70% chiu cao nhm

nhm c chn trn c s dung sai :

Khi ng knh lp ghp >50mm:

RZ = (0,1~0,15)

Khi ng knh lp ghp trong khong 18~50mm: RZ = (0,15~0,2)

Khi ng knh lp ghp

2. Qu trnh n mn ha hc trn b/mt

nhm nh hng ln n tnh chng n mn ha hc ca b mt chi tit

Cc ch lm cha cc tp cht nh axit, muiCc tp cht n mn b mt theo sn dc ca nhp nh v to thnh nhp nh mi. Nh vy, b mt c nhm cng cao th qu trnh n mn cng nhanh

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X. /hng ca bin cng n TCSD

B mt bin cng tng bn mi ca chi tit ln khong 20%, tng chng mn ln 2~3 ln (hn ch kh nng gy ra cc vt nt ph hng chi tit)

B mt qu cng lm gim bn mi ca chi tit

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XI. /hng ca ng sut d n TCSD

ng sut d nn trn b mt tng bn mi ca chi tit, cn ng sut ko gim bn mi ca chi tit

V d: b mt chi tit thp c ng sut d nn tng bn mi ln 50% v c ng sut d ko s gim bn mi 30%

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XII. Cc y/t /hng n /nhm b/mt

1. Thng s hnh hc ca dao

2. nh hng ca tc ct

3. nh hng ca lng chy dao

4. nh hng ca chiu su ct

5. nh hng ca vt liu gia cng

6. nh hng ca rung ng

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1. Thng s hnh hc ca dao

a) v b): S1>S2 ta c RZ trn hnh

b nh hn RZ trn hnh a

c) v d): hnh dng nhm thay i theo bn knh mi dao

e) bn knh mi dao r2 tng s lm gim nhm b mt

g) cc gc chnh v gc ph 1 c nh hng n nhm

Thng s hnh hc ca dao nh hng n nhm

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2. nh hng ca tc ct

Khi V nh, bin dng t, nhit ct khng cao, do RZ thp. Nu V tng gn 20m/ph th nhit ct tng ln hng nghn nn sinh ra lo dao, lo dao lm thay i hnh dng mi dao lm tng RZ . Nu tng V ln na (100 m/ph), lo dao bin mt v RZ gim

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3. nh hng ca lng chy dao

Nhn chung, khi tng lng chy dao S th nhm tng v bin dng do, bin dng n hi v rung ng. Nu S>0,15 th nhm tng nhanh (do bin dng n hi)

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4. nh hng ca chiu su ct

Chiu su ct nhn chung khng c nh hng ng k n nhm b mt g/c

Tuy nhin, nu chiu su ct qu ln th rung ng ca qu trnh ct ln s lm tng nhm

Nu chiu su ct qu nh s gy ra hin tng trt dao trn b mt g/c nn nhm tng. Hin tng trt dao xy ra khi t < 0,02~0,03 mm)

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5. nh hng ca vt liu gia cng

Vt liu do v dai (thp t cacbon) d bin dng, do nhm tng

Vt liu cng v gin (t bin dng), do nhm gim

Gim tnh do ca b mt gia cng bng bin cng cng lm gim nhm

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6. nh hng ca rung ng

Rung ng lm thay i iu kin ma st, gy nn sng v nhm trn b mt gia cng

Rung ng sinh ra do nhiu nguyn nhn:

Tnh trng ca my

cng vng ca dao, chi tit v g

Gia cng vi ch ct khng hp l

Gia cng khng c dung dch trn ngui

Vt liu gia cng c tnh do cao

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XIII. P/php t bng b mt (1)

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XIII. P/php t bng b mt (2)

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XIV. P/php t cng b mt (1)

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XIV. P/php t cng b mt (2)

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XV. P/php t ng sut d b mt

Tng tc ct V hoc lng chy dao S cng c th tng hoc gim ng sut d

Lng chy dao S tng lm tng chiu su c ng sut d

Gc trc c tr s m gy ra ng sut d nn

Gia cng vt liu gin bng dng c ct c li to ra ng sut d nn, cn gia cng vt liu do thng gy ra ng sut d ko

Gia cng bng mi thng gy ra ng sut d ko, cn gia cng bng ai mi thng to ra ng sut d nn

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XVI. P/php nh gi nhm b mt

Phng php quang hc (dng knh hin vi)

Phng php o nhm bng my o profile

Phng php so snh bng mt (trong cc phn xng SX ngi ta mang vt mu so snh vi b mt gia cng v kt lun xem thuc cp bng no)

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XVII. P/php nh gi bin cng

Dng my o cng (tc dng ln b mt mt lc P, sau xc nh din tch S ca b mt do du kim cng n xung)

Cng thc tnh bin cng H:

H = P/S

H bin cng (N/mm2), P- lc tc dng ca u kim cng (N), S- din tch do u kim cng n xung (mm2)

chiu su bin cng dng u kim cng tc ng ln lt xung b mt mu t ngoi vo trong, sau mi ln tc ng ta o din tch b ln S n khi S khng thay i th dng li v o c chiu su b/c

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XVIII. P/php nh gi ng sut d

Phng php tia Rnghen (dng tia Rnghen kch thch ln b mt mu mt lp dy

5~10 m v sau mi ln kch thch ta chp nh th Rnghen. Phng php ny cho php o c c chiu su bin cng. Tuy nhin, phng php phc tp v tn thi gian cho iu chnh th Rnghen (10 gi cho mt ln o)

Phng php tnh ton lng bin dng (sau khi ht tng lp mng kim loi bng PP ha hc v in c kh ta tnh lng bin dng ca chi tit mu. Da vo lng bin dng ta xc nh c ng sut d

TS. Trng c Phc


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