NGHIEN CIJIU KHOA HOC
\A' HIET KE VA CHE TAO THIET S\ DO DAC TRU'NG GIAN HAI CHIEU CUA v A l DET KIM
DESIGN AND MANUFACTURE DEVICE FOR MEASURING TWO DIREC- TION STRETCH OF KNITTING FABRIC
KS. Ldu Thi Hdng Nhung\ TS. Nguyin Thi Thuy Nggc', TS. Nguyen Van Vinh^
'Trddng Dai hpe Sd pham Ky thuat Hflng Yen
^Trfldng Dai hpe Bach Khoa Ha Ndi
TQM TAT
Do co gidn cua vdi cd y nghia ddc biet trong thiit ki, sdn xudt vd sd dung qudn do bd sdt.
Hiin nay, cdc phUdng phdp do do gidn cua vdi det kim chu yiu thUc hien theo mgt chieu, cho nen chUa phdn dnh dung thUc ti ddc diem lUc tdc dung vd biin dang cua vdi khi qudn do dUdc mac tren cdthengUdi. Bdi bdo ndy trinh bdy kit qud thiit ki vd chi tao thiit bi BT2014 do dac trdng gidn hai chiiu cua vdi. Thiit bi hogt ddng theo nguyin ly keo cdng mdu vdi theo hai chieu vuong goc vdi lUc kio CO thi thay doi ddc lap. LUc keo cdng ldn nhdt cua thiit bi la 5±0,1 N, do gidn ldn nhdt cua mdu vdi Id 180%, dc chinh xdc do bii'n dang tuyet doi cua mdu vdi la 0,1 mm.
Td khoa: Kio gidn hai chieu, dgc trUnggidn, vdi det kim.
ABSTRACT
The elasticity of the fabric has a special meaning in designing manufacturing and utilizing tight clothes. Current methods for measuring knitting fabric stretch are mainly one way, which doesn't precisely reflect the affected points by force and deformation on clothes when worn.
This paper presents the results of the designing and manufacturing of equipment BT2014 to measure two-dimension stretch of knitting fabric. Device's operation is based on the principle of two-direction stretch in perpendicular to the dragging force that may change independently. Maximum tensile strength of the device is 5±0.1N, the largest stretch of fabric samples is 180 %, accurate absolute measurement of sample deformation fabric is 0.1 mm.
Keywords: Two direction stretch, stretch property, knitting fabric.
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NGHIEN ClJfU KHOA HOC
1. GIOI THIEU
Vai det kim hiln nay dflpc ddng nhilu de thilt ke va san xuat quan ao bd sat sfl dung trong dieu kiln sinh boat thfldng ngay trong the thao va trong y te do vai cd dp thoang khi eao, hut Sm tdt va dac bilt kha nang co gian dan hdi cao. Khi ca the ngfldi mac quan ao bd sat van ddng, vai chiu tac dung eua lflc keo eang ddng thdi theo n h i l u chilu khae nhau. De ngfldi mac ludn cam thay thoai mai khi van ddng va hinh dang quan ao bd sat gid ddpc on dinh can phai dam bao dp gian va kha nang phuc hdi cua vai trong gidi ban cho phep.
Vile xac dinh va danh gia kha nang eo gian cua vai theo md hinh keo gian nhieu ehieu la phu hpp vdi thde t l va can thilt. Tuy nhien, cac phflpng phap do dp gian cua vai det kim td trfldc d i n nay chu y i u thfle h i l n theo mdt chilu [I]. Theo nhdng phdOng phap do nay vai chiu tae dung lflc mdt chieu theo phflpng cpt vdng hoac hang vdng cua vai, vi vay, cac phflpng phap do nay chfla phan anh dung thfle t l eda dac diem tac dung ldc va bien d ^ g eua vai khi quan ao ddpe mac tren co the ngfldi. Gan day da ed mpt so md hinh thfle nghiem keo gian vai theo nhieu chieu dflpc nghien cdu va ap dung ddi vdi mdt sd lo^i vat lieu [2]. Khi thd nghiem keo hai chieu doi vdi vat lieu vai, cac cdng trinh nghien cflu da tiln hanh tac dung lflc trung vdi 2 phflpng det cbinb cua vai. Md hinh nay cung da dflpc thd nghiem ddi vdi vat lieu tdng hpp va d^t ddpc k i t qua nhat dinh [2].
De tien tdi md hinh keo gian nhieu chieu giong vdi d i l u kiln thfle t l vai bi keo gian, viec Ifla chpn phflPng phap keo gian hai chieu la hoan toan phu hpp. Day la cP sd bfldc dau de phat trien phdong phap thd nghiem keo gian vai theo nhieu ehilu.
2. KET CAU VA NGUYEN LY HOAT DONG CUA THIET BI DO
Nguyin ly tao thanh lflc keo eang va do lflc keo cang mau vai F, va F^ the hiln trong hinh 1.
Khi dat dpc l|p 2 mdmen M^ ho?c M^
cap vit me dai dc V^ va V se tao ra chuyin dpng tinh tiln ngflpc ehieu cda cae ham kep nhd cap banh rang doi chieu B, va B . Cap lflc keo F^va Fj dflpc xac dinh bdi 2 lflc ke LKF^ va LKF^
cd dp cbinh xae 1%. Phep do quang dflpc thfle hien bdi mdt camera CCD 600x800 diem anh va ong kinh 16 mm. Dp phan giai tdi da cda he thong la 0,02 %.
Hinh 1.2a. Sd do nguyen ly tao vd do lUc keo cdng mdu vdi
Hinh 1.2b. Sd do he quang
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NGHIEN cufu KHOA HOC
Kich thfldc vung khao sat tren mau Chilu rdng phan kep 70 mm.
v4i dflpc xac dinh theo nguyen ly khuyech dai quang hpc tren hinh 1.2b va dflpc xac dinh theo cdng thde:
/'>
=PV =PnSfed) 0 0 792.9489
0 29 9.5238
alpha _c*
fcQ) 0 0 794.0980 231.6737
cc(l) ceil) 1 fc{\)
Trong do: fc(l) la khoang each tieu efl cac pixel theo ehieu nam ngang (dPn vi la mm); fc(2) la khoang each tieu efl cac pixel theo chilu thing ddng; ec: Diem gdc thfle cua anh;
alpha_e: H? sd xien.
3. KET QUA THIET KE VA CHE TAO THIET BIDO
Kit qua kiem nghiem dp chinh xac cda thiet hi: Lflc ke co hpe cd pham vi do 0,1 N-^ 5 N; Phan dp nhd nbSt 0,1 N; Sai sd tdi da 1 %;
Tham sd caUp ed dp phan giai \k 0,02 % bien dang, dp chinh xac do kich thfldc 0,1 mm.
Trong dd: p la he sd khuech dai he quang; 1' = nd vdi n: So pixel anh thu dflpc; 6:
Kieh thfldc cda pixel CCD.
Dl dim bao dp ehinh xac cua he do quang vi?c ealip ealib eho camera vdi ma tr^ji dflpc tinh nhfl sau:
Hinh 1.3. Thiit bi che tgo
3.2. Danh gid kha nang do cua thilt bi Do chfla cd thiet bi do dp gian eua vii det kim theo hai ehilu nin viee Idem nghiem thiet bi do BT2014 dflpc tien hanh theo phdong phap so sanh viee do dp gian mpt chilu cua vai tren thiet hi nay va phflpng phap treo tai trpng CO dinh Tensilon cda Nhat Ban. Ddng thdi tiln hanh do ISn Iflpt theo hai ehieu tac dung lflc cua thiet hi dl kiem tra dp ddng nhat. Viee kiem nghiem ddpe tien hanh vdi mau vai dit kim 100% polyamide ed d ^ g hinh chfl nh?t kich thfldc 170x50 (mm) thu dflpc kit qui nhfl hinh 1.4.
3.1.'Ihdng so thiet ke cua mo hinh Thilt hi BT2014 do dac trflng gian hai chilu cua vii det kim dflpc thiet ke va che tao cho phep do mau vii vdi kieh thddc ldn nhat 250x250 (mm); Kich thfldc vung khao sit tren mSu vai 50x50 (mm). BChoang each nhd nbSt gifla hai ngam kep la 165 mm va Idn nhat la 300 mm; Bin k?p mau cd kich thddc 120x20 (mm);
Bieu dd kit qui do eho thay dp gian eua mau vai khi tien hanh do vdi hai phfldng phap la kha gSn nhau. Dd sai leeh khi do theo phflpng phap treo tai trpng co dinh so vdi khi do bang thilt hi BT2014 theo chilu lflc kl LKI la 1,71 % va theo chilu ldc kl LK2 li 0,17 %. Dp sai lech gifla hai ehieu do tren thilt bj la 1,65
%. Kit qui nay cho th&y thiet bi do dp gian hai chieu cua vii det kim BT2014 dat yeu cau.
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NGHIEN Cflu KHOA HOC
• B 6 gJSn cua vai do tr6n thifit b|
chieu lire k l vang
• Do gian cOa vdi So trSn thifit bi c h i l u li/c kfi do
• && gi3n cua v i i do bang phifong phap treo t i i trtjng
Hinh 1.4. Biiu dd so sdnh do gidn cua mdu vdi khi do tren thiit bi BT2014 vd do theo phUdngphdp treo tdi trong CO dinh
4. THU* NGHIEM DO DAC TRU^G GIAN CUA MOT SO MAU VAI DET KIM Viec thd nghiim do dae trflng gian eua thilt bi BT20I4 dflpc tien hanh theo md hinh keo gian mdt chu trinh vdi mau vii 100% polyamide hinh chfl thap. Lflc keo eang ban dau 0,1 N, lflc tae dung theo hai ehieu la bang nhau va khdng ddng thdi. Kit qua do dflpc the hien tren hinh 1.5.
Bieu do cho thay quy luat thay ddi dp gian eua mau vai khi tic dung lflc va khi bd lflc gidng nhfl khi do dp gian theo mpt chilu. Qua trinh thd nghiim trin thilt bi BT2014 cho thay hoan toan xac dinh dflpc cic thanh phan biln dang hai chieu cua mau vii theo md hinh keo gian mdt chu trinh. Lap lai nhilu lan qua trinh thd nghiim keo gian mdt chu trinh vdi thiet hi BT20I4, cd the tiln hanh ddpc cie thd nghiem keo gian nhieu ehu trinh.
• £}$ gi3n cOa mSu vSi theo chi^u c$t vdng khi tac dgng lire
• {)$ g i i n cOa m i u vai theo chigu hang vong khi tac dung Iyc
•* €)9 gian cua m i u vai theo c h i i u c$t vong khi thdi tac dgng Iyc
• £)$ gi9n cua m i u vdi Iheo chi4u h^ng v6ng khi thdi tac dgng Iyc
Hinh L5. Bieu do gidn cua mdu vdi khi chiu tdc dung cua lUc keo hai chiiu bdng nhau vd khdng dong thdi
theo md hinh keo gidn mdt chu trinh '
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NGHIEN CUTU KHOA HOC
5. KET LUAN
Qua trinh thd nghiem cho thay thilt hi cd kha nang do dflpc cae dac trflng gian hai chieu cua vii theo md hinh nda ehu trinh, mdt chu trinh va nhieu chu trinh. Do cP cau tac dung lflc chfla dflpc dieu khiln tfl ddng nen khi do theo md hinh nhieu chu trinh se mat nhieu thdi gian.
Pham vi do cua thiet hi BT20I4 cho phep thfle hien tren nhilu loai vai vdl kha nang gian khac nhau. Cae kit q u i thd nghiim theo eac md hinh keo gian doi vdi mdt sd loai vii cho thay thiet hi lam viec on dinh va tin cay Thilt hi nay la eP sd de phat triln thilt bi do tfl ddng dp gian hai ehieu cda vai det kim. •
Ngay nhan bai: 12/8/2014 Ngay phan bien: 18/9/2014
Tai lilu tham khao:
[1]. David Alejandro Arellano Escarpita, Diego Cardenas, Hugo Elizalde, Ricardo Ramirezand Oliver- Probst (2012) "Biaxial Tensile Strength Characterization of Textile Composite Materials" 10.5772/48105.
[2]. Willems, A.,Vandepitte, D.,Lomov, S.V.,Verpoest, I. (2005) "Biaxial tensile test sona woven glass/ PP fabri cusing optical strain measurement," Proc. 7th ESAFORM Conference, Cluj-Napoca.
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