NGHIEN CUU-TRAO D I HIEU C H l AN MAY KEO NEN VAN NANG CO DO CHINH \ A C CAO CALIBR^^TION OF UNIVERSAL TESTING MACHINE W ITH HIGH ACCURACY LEVEL TS Lutmg Hong Sara Truong Dai hpc Tran Dai Nghia TOM TAT Hec hieu chudn mdy thi nghiem keo nen vgn ndng luon chiem mpi voi tro quan trpng nhdm ndng cao dp chinh xdc tmng cdc thi nghiem keo nen tidn cdt vd xdc dinh modul ddn hoi theo tieu chudn TC I '.V vd 4STM Bdi bdo gidi thieu phirong phdp hieu chudn mdy keo nen vgn ndng cdp tdi 300 k.\ vd 500 k.\ chung tot thiet ke che tgo Sau hieu chudn mdy dgt dirac dp chinh xdc cao thuc hien cdc thi nghiem ddp ung nhu cdu cdp thiet cho viec hpc lap, nghien ciiu khoa hpc vd sdn xudt mpt sd tnrdng dgi hpc trung ldm kiem djnh, nhd mdy Tir khoa: \hi\ thi nghiem vgn ndng: Tieu chudn AST,\f ES: Hieu chudn ABSTR.\CT The calibration of testing machine always play an important role to improve accuracy level in stretching, compressing, bending, cutting experiments and determination modulus according to 7'C^\ ASTM standards This paper presents a calibration of elastic method for 300 k\ and 500 k\ testing machine designed, manufactured by us After calibration, the machine archive high accuracy level when conducting experiments, meets urgent needs of studying, scientific research, production in several universities, testing center, plants Keywords: Testing Machine ASTM E8 Standard ISSN 0866 - 7056 TAP CHi CO KHi VIET NA.M S6 nam 2016 www.cokhivit'tnani.vn Calibration manufacturing NGHIEN CU'U-TRAO OOl I GIOI n i l E t CHLNG 2.CHET.AO MAY KEONEN \ AN NANG Tai Viet Nam phiin ldm eac may thi nghiem keo, nen vat lieu deu duac nhap khau tir nuoc ngoai Xuat phat tir nhu cau thuc tien, chiing toi da nghien cuu thiet ke va che tao cong may thi nghiem van nang dieu khicn servo cap tai 300 kN 500 k\ duac gia tai thiiy lyc vai he luong dicu khien, xu ly so lieu thi nghiem co sy tra giiip ciia may tinh va phan mem chuyen dung May thoa man mpt so tieu chuan thi nghiem TCVN va tieu chuan ASTM cac thi nghiem keo, nen, uon cat va xac dinh modul dan hoi ciia vat lieu thep, be tong, go, chat deo hay cau kien can thi nghiem De may keo nen van nang co dp chinh xac thi nghiem cao thi ngoai viec che lao he thong co CO dp chinh xac, dp cung vijng cao, he thong luong dieu khien va xu ly so lieu thi nghiem co chinh xac, dp tin cay cao thi viec hi?u chuan he thong may thi nghiem van nang chiem mot vai tro dac biet quan Viec hieu chuan may thi nghidm keo nen van nang bao gom hieu chuan cam bien lyc (load cell), cam bien chuyen vi (displacement transducer), cam bien dp gian dai cue bp (extensometer) bien dang toan the may duai tac dung ciia tai Irpng qua trinh thi nghiem Bai bao chi giai thi?u qua trinh hieu chuan cac cam bien cho may cap tai 300 kN va 500 kN 2.1 Che tao khung may chinh ^:r M Khung may duac thiet ke dya tren nguyen ly tao lyc kep [6] de co the ciing tao lyc keo va nen Chuyen dpng ciia ban gia tai dupc dieu khien chinh xac bang he thong van servo thiiy lyc de tien hanh cac thi nghiem theo cac tieu chuan \STM hoac TC\ N lya chpn (hinh 1) He thong luong va dieu khien se dieu khien toan bp qua trinh thi nghiem cua ma> tinh toan cac ket qua thi nghiem va xual cac ket qua thi nghiem Cac phan chinh cua khung may dupc che tao bao gom: De may, ban gia lai true \ it, true tran ia\ don tren, tay don duai piston, xi lanh ihiiy lyc va cac ga phuc vu cho cac thi nghiem bao gom: Ma kep mSu tron, ma kep mau d?p; ga cho thi nghiem nen kim loai; ga cho thi nghiem cat kim loai; ga cho thi nghiem uon kim loai; ga cho thi nghidm uon be long diem Sau thiet ke khung may, mo phong ung suat, bien dang, ciia cac chi tiet khung may va chuyen vi ciia ca he thong khung may [6] De tai da che tao toan bp cac chi tiet ciia khung may, cac ga cho cac thi nghiem chuyen diing va lap dat h? thong co hoan chinh (hinh 1) po^ Hinh I Cdu tgo bp khung chiu luc cua mdy thi nghiem keo nen 300 k\ 500 k.\' 1.2) Tay ddn: 3} True vit-me 4) Tru tran: 5) Mau thir: 6) Bdn gia tai: 7) Xi lanh ihiiy luc: H) Dv ma\ Mdy sau che tgo (a): Dd gd cho cdc thi nghidm keo (bt: S'L'H IC) Cdt (d): Udn fej ISSN 0866-7056 TAP CHi CO KHi VIET NAM, S6 nam 2016 www.cokhixi-inam.vn NGHIEN Cl>U-TRAO D O I 2.2 \ay dirng he thong dieu khien cho may keo nen He thong dieu khien cua may keo nen CO vai tro dac biet quan trpng viec thyc hien cac thi nghiem va dam bao dp chinh xac cac thi nghiem De dam bao dp chinh xac cho may thi nghiem keo nen la cap 1, lam \ lec on djnh thi cac thiet bi luong dieu khien ciia may dupc chpn cho co dp chinh xac cao, co the mua hoac che tao duoc tai Viet Nam Tren co sa de tai da chpn mua cam bien lyc la load Cell 363YH ciia hang ANYLOAD Canada, cam bien chuven \i dang trupt Novotechnik (Due), cam bien bien dang cue bp tren than mau dang strain gauge based ciia hang SATEC (M\), he thong thu thap tin hi^ucam bien va dieu khien he thong duac sir dung la Card National Instruments PCl-6221 (My) van servo dupc sir dung thupc hang Moog model 761 (Dire) Voi cac thiet bi luong \a dieu khien do, de tai tien hanh thiet ke, che t^o bp khech dai tin hieu cho cac kenh va xay dyng giai thuat dieu khien FID cho may thi nghiem keo nen 16] 2.3 Xay dung phan mem cho may keo nen phan mem may keo nim bao gom: Chuong trinh chinh PNX-MTS: Dieu khien thiet bi thu thap s6 lieu, lap bao cao Cac chirc nang chinh bao g6m: Cai dat cac thong s6 phan cumg; Hieu chinh (Calibration) may bao gom lyc chuyen \i bien dang; Keo kim loai theo tieu chuSn ASTM E8 TC\'N 1997-2002 [\]; Nen kim loai theo iicu chu^n ASTM E9-09 [IJ, U6n kiiii loai Iheo tieu chuin TC AN 198-2008 [5J; Lon be long theo tieu chuAn ASTM C78-02 [3]; Cat kim lo?i theo tieu chuan ASTM F606-10 [4]; Xac dinh modul dan h6i E theo lieu chuin ASTM EI 11-04 [2] Chuang hinh PNX-Report Creator - Diing de lap bao cao, co the chay tren nhieu may tinh khac Chuang trinh PNX-Data converter - Diing de chuyen doi file diJ li?u Phan mem \a giao dien dieu khien may keo nen dupc trinh bay [6] HIEL CHLAN CAC CAM BIEN Trong he thong thu nhan va xu ly tin hieu ciia may keo nen, duai su thay doi cua cac dai lupng vat 11 nhu: Lyc/Chuyen vi/Ap suat/Nhiet dp thi cam bien tuang img se thu nhan sy thay doi duai dang lin hieu di?n (Analog/Digital) Tin hieu thu dupc tir cam bien dupc chuyen den bp xir li tin hi^u (Signal Conditioning) de khech dai, Ipc nhieu, sau chuyen sang bp chuyen doi tir Analog sang Digital (AD converter) Tin hi^u digital se dupc chuyen tin hieu dang nguyen goc hay cac dai lupng vat ly can Dp phan giai (buac do) ciia phep se phu thupc vao dp chuyen doi AD Dp chinh xac va on djnh ciia ket qua thi nghiem phu thupc vao cac yeu to nhu cam bien (Sensor/Transducer), khech dai tin hieu (Signal conditing) va bp chuyen doi AD Voi cac thiet bi lucmg co hpc cung nhu dien tu, theo thai gian va so lan sir dung dp chinh xac se giam di, rieng vai thiet bi luong dien tir thi so dpc CO the hi Iroi (drift) lam ic-ch vi tri zero ban dau Nhu vay, Iruac sir dung thi tit ca cac thiet bi phai dupc hi$u chuan de dam ISS.\ 0866-7056 TAP CHi CO KHi VIET NAM S6 nam 2016 www.cokhivietnam.vn NGHIEN CU'U-TRAO 0(^1 bao dp chinh xac ciia cac phep Ngoai hieu chuan la bi^n doi tin hieu dien thu duac tir cam bi^n (sensor/transducer) gia tri mpt dai luong vat ly ky thuat (Engineering Unit) 3.1 Hieu chuan cam bien luc (load cell) Dung cu va phuang tien hieu chuan: Hieu chuan load cell la tim quan he giira lyc chuan (dupc bang thiet bi chuan) v dien ap Day la mpt nhumg van de kht ciia de lai la lam co dupc cac dung cu, phuang tien co dp chinh xac va co phuang phap phii hpp de hieu chuan cac cam bien lyc Trong de tai da sir dung load cell tieu chuan 82-EO100/BS dap ung tieu chuan ASTM E74 Class A lyc thir max la 300 kN gan true tiep len ban gia tai may keo nen (hinh 2) Ham hieu chuan: Ham xap xi tin hieu dien tir cam bien ihanh dai lupng vat ly (engineering unit) dupc sir dung ba loai ham xap xi da thiic tir bac den bac co dang: \ = k,, -»- k|X| + k,.\, + k,x, Cac loai cam bien lyc va chuyen vi co dp tuyen tinh cao nen co the chpn ham xap xi bac 1; y = k,, + k|X| Trong thyc le duong quan he lyc dien ap chuyen vi - Dien ap co dupc tir cac loai cam bien thuang co quan he phi tuyen nen xap xi tuyen tinh va phi tuyen bac deu CO dp chinh xac khong cao Vi vay co the su dung them ham hieu chinh SPLINE Day la ham cho ket qua chinh xac tai v i tri diem chuan v a duong cong xap xi lien luc den dao ham bac nhat tai diem chuan Nhu vay, lin hieu co dp phi luyen cao thi kel qua xap \i van rat chinh \ac Trong de tai cam bien lyc (load cell) co dp tuyen tinh cao nen co the chpn ham xap xi bac 1: y = k,, + kjX| Thuat loan hieu chuan va thyc hanh hieu chuan dupc thyc hien bang phan mem tich hpp phan mem ciia may keo nen (hinh 3) Hinh 2: Thiet hi hieu chudn vd hieu chudn Load cell mdy keo nena} Load cell tieu chudn: b) Tien hdnh hieu chudn: c) Thiet bi hien thi so lieu Hinh Phdn mem hieu chudn load cell ISSN 0866-7056 TAP CHi CO KHi VIET NAM S6 nam 2016 wwv\.cokhi\ieIn.im.vn NGHIEN cuu-TRAO DOI 3.2 Hieu chuan cam bien do gian dai (Extensometer) Dung cu va phuang tien hieu chuan: De hieu chinh Extensometer can thiet bi chuan chinh xac va phuang phap phii hgp Bp hieu chinh bao gom, dau trac vi ke chinh xac True va dau trac vi ke dupc gan vao khung va thuoc gian gan gi&a true iTnh va true chuyen dpng Dp dich chuyen dupc bieu thi qua man hinh s6 Extensometer dupc kep vao cac bp dieu hpp co the hoan doi cac kich ca mau khac Mot niia bp dieu hop co the dieu chinh trony iio nua giir on dinh Khi dieu chinh trac \i ke bp dieu hpp Iren chuyen dpng va dp dich chuyen duac ap vao thuac gian Dp gian dupc dpc tir man hinh so ciia dau trie \ i ke (hinh 4) Mot so Ihiet bi diing hi?u chuan Extensometer cho bang sau: Loai Hanh trinh (tr^c dirng) D$ phan giai CP103368 Ten san pham Bg hi?u chinh ky thuat so thudc gian cho dp phan giai 1.0 micron Bg hi?u chinh ky thuat so thudc gian CPlO.Us'J cho dg phan giai 0.1 micron 50 mm I microns 50 mm 0.1 microns Hmh Thic! h, lucii < hmh / i/ nsomcicr de tdi Ham hieu chuan: Hieu chuin Extensometer la tim quan he giira djch chuveii thyc ciia Extensometer va dien ap Vi quan he cd tinh phi tuy^n rit cao nen sii dung ham xip xi SPLINE Thuat loan hieu chuan va ihyc hanh hieu chuin Extensometer duac thuc hien bing phin mem tich hpp phan mdm ciia may keo nen (hinh 5) Hinh Hieu chudn cdm bien dp gidn ddi 3.3 Hi^u chuan cam bien chuyen vj (LVTD) Dung cy va phuang tipn hieu chuan: Hieu chuan cam bien chuydn vi la tim quan he giira dich chuyen thyc ciia cam bien va dien ap Dung cu hieu chuan chi can thuac cao co dp chinh xac I/IOO Dung cu hieu chinh dupc the hi$n tren hinh 6a ISSN 0866 - 7056 TAP CHi CO KHi VIET NAM, S6 nam 2016 www.cokhivietnam.vn NGHIEN cuu-TRAO DOI Ham hieu chuin: Hieu chuan cam bien chuydn vi (LVTD) la tim quan he giira dich chuyen thyc ciia cam bien va dien ap Vi quan he co tinh phi tuyen nen sir dung ham xap xi bac 3: y ^ k^ + k^x, + k^x, + kjXj Thuat toan hieu chuan va thuc hanh hieu chuan cam bien chuyen vj dupc thyc hien bang phan mem tich hop phan mem ciia may keo nen (hinh 6b) keo mau chuan nhu Ket qua cho thay ca lan keo, kdt qua thi nghidm sai khac nho khong qua 1% (hinh 7a) 4.2 Thi nghiem kiem chung chinh xac nen Tien hanh nen mau kim loai trdn may tidu chuan ciia Nhat va may thi nghiem vai ciing mpt loai mau v a lieu chuan nen dd doi chung kdt qua Ket qua thi nghiem sai khac nho hem 1% BQ danh gia dp chinh xac lap nen, tidn hanh nen mau kim loai ciing loai, ciing tieu chuan nen Kdt qua lan nen sai lech khdng qua 1% (hinh 7b) Hmh 6: Thudc cao (a), phdn mem hieu chudn cdm bien chuyen vf (b} DANH C i l A K E T Q L A Sau hieu chuan cac cam bien de danh gia dp chinh xac cac thi nghiem ciia may keo nen, de tai da tien hanh cac thi nghi?m kiem chimg Viec kiem chirng dupc thyc hien vcri cac thi nghiem keo, nen, uon va cat kim loai doi chieu vdi may keo nen van nang lieu chuan 4.1 Thi nghiem kiem chirng dp chinh xac keo Tien hanh thi nghiem keo ciing mpt loai mau kim lo^i theo ciing mot tieu chuan tren may lieu chuan ciia Nhat va may thi nghiem Ket qua cho thay sai khac kdt qua giflra may tieu chuan va may thi nghiem khoang !%• ^^ danh gia dp chinh xac lap lai cua thi nghiem keo tien hanh thi nghiem L Hinh Bieu keo (a), nen (b) mdu de kiem chung chinh xdc lap keo, nen 4.3 Thi nghiem kiem chiing chinh xac cat Tien hanh cat mau kim loai nhu tren may ciia Nhat va may ciia de tai Kdt qua thi nghidm sai khac nho han 1% Be kiem chimg dp chinh xac lap cat, tien hanh cat mau kim loai ciing kich thudc, eiing vat lieu va ciing tieu chuan Ket qua lan thi nghidm (hinh 8a), sai lech khdng qua 1% 4.4 Thi nghiem kiem chung chinh xac lap uon kim loai ISSN 0866 - 7056 TAP CHi CO KHi VIET NAM, S6 nam 2016 www.cokhivietnam.vn NGHIEN CLfU - TRAO eOl Ticn hanh uon mau kim loai ciing loai va ciing tieu chuan dd kidm tra dp chinh xac lap uon vat lieu (hinh 8b) ca lan uon sai Idch pham vi cho phep —