NGHIEN CUfU - TRAO 061 NGHIEN Cl>U - THIET K6 THIET Bj TAO GIA T C D^ KISM TRA KHA NANG CHIU Lire QUAN TINH CLIA NGOI DIEN TIJ STUDY TO ENGINEERING DESIGN ACCELERATION MACHINE TO CHECK TOLERANCE OF INERTIAL FORCE FOR ELECTRONIC FUSES Doan Hoc Dan, Dang Dire Th^ng, Hoang Hirag Hge vien Ky thuat Quan sir TOM TAT Bdi bdo trinh bdy tdm tdt nguyen tdc bien ddi nang luong cua hi vgt va cham vd nhimg bien doi dgng ndng cua vgt rai tudod nhihig cao khdc Thiet ke thiet bi tao gia tdc di hem tra khd ndng chiu luc qudn tinh ciia ngdi dien tic Thuc nghiem dgc vd tinh todn gia tdc cua vgt rai vai khoi lugng vd dgi cao rai khdc nha thiit bi quan sdt la Camera thuat phong Tir khoa: Thiet bi tao gia tdc, luc qudn tinh ABSTRACT The article presents the principles of energy conversion for the system of objects when they collide and dynamic change of an object in free fall at different heights Study to engineering design acceleration machine to check tolerance of inertial force for electronic fuses We take experimental measurements and calculate the acceleration of an object infreefall with different masses at different heights with special camera Keywords: Acceleration eqquipment, inertial force ISSN 0866 - 7056 TAP CHi CO KHi VIET NAM, S6 nam 2015 w«-w.cokhi Vietnam.vn NGHIEN CUfU - TRAO DOI DAT VAN DE Khi thiet ki, chi tao ngoi dan noi ehung va ngoi dien tu noi rieng, eo nhiiu ngi dung nguai thiet k i phai tiin hanh kiim nghiem, mpt npi dung bat huge la: Kiim nghiem kha nang chiu lire quan tinh ciia khii dien hi Vi vay, cin mgt thiet hi tao gia toe Ion giong nhu phat ban de kiem tra danh gia dp ben va su lam viec tm cay cua ngoi Mgt vai ca sa ky thuat quan dgi co trang bi thiet bi (nhu bua Maccet hoae thiet bi thii rung, soc cua hang ShinkenNhat), nhien, gia cua no tuang doi cao Hge vien Ky thu^t Quan su la mgt eo sa dao tao va nghien ciiu khoa hgc co uy tin quan dgi, viee che tao hay mua sam cac thiet bi thu nghiem de phuc vu nghien ciiu khoa hpc la c4n thiet Vi vay, nhom nghien ciiu d i tai: "Nghien ciiu thiet ke, ehe thii thiet bi tao gia toe de kiem tra kha nang chiu luc quan tinh ciia ngoi dan dien tu", dugc dat nham thoa man viec giang day, nghien ciiu khoa hpc ciia thay va tro Hgc vien vai nguon kinh phi hgp ly va tao gia toe khoang 5000g din 15000g NQI DUNG 2.1 B^i toan nang lirffng cua v3t roi tru-dc va sau va cham voi nen |1][2][3] jG) Khoang thai gian dugc gpi la thai gian va cham va dugc ky hieu la T Hien tugng va cham dupe gap nhieu thuc te, nhu ren, dap, dong cgc, nghien vat lieu, tao gia tic, vv Chinh V] van toe vat va cham bi biin dii h-ong khoang thai gian rat be nen dua vao hien tugng ta tao thiet bj tao gia toe Ion Khao sat hien tugng: Tha mgt vien bi rcri tu tir dp cao h, xuong mat phang ngang co dinh Sau va cham vao mat phing ngang e i dinh vien bi len vai cao b^ (hinh 1) De tim he so khoi phuc k ta can tim van toe v^ va u^ ciia vien bi truac va sau va cham Vien bi rai tir dp cao h, khong eo van toe ban dau nen va cham vao mat phang ngang no co van toe: v^ ^ V^Sl^i • Do chinh la van toe tuang doi ciia vien bi doi vofi mat phang ngang truac va cham De tim van toe tuang doi ur ciia vien bi sau va cham ta nhan xet rang ehinh nho van toe u^ ma vien bi len dugc dp cao h^ Vay: u = V^g^z Do do: k = il= Mi: rt Bay gio ta tinh ton hao dgng nang va cham Ggi T, va T^ lan lupt la dgng nang cua ca he truac va sau va cham f^ Tl = m i v j + - m2v|; T2 = - m i u | + - miu^ Hinh I Md hinh vdi Do do, iugfng mat dgng nang bang: Va cham la mgt truang hgp dac biet ciia ehuyin dgng ca hpc, do, van toe cac chat diim cua co he biin dii hiru han khoang thai gian rat be khoang lO"^ din 10^ giay, AT = Ti T2 = - mi(v2 - u;) + - m2(v| - u | ) Bay gia ta bieu dien lugng mdt dgng n a n g ^ ^ ISSN 0866 - 7056 TAP CHI CO KHf VIET NAM, 86 nam 2015 www.cokhivietnam.vn NGHIEN CUfU-TRAO Ddi theo cac thong s6 dgng hgc ciia ca he truac 2.2 Giai bai toan va cham Muon thi ta viit phuong trinh ton hao dgng nang a dang sau: Cho vat nang binh tru eo ichoi lugng m, duang kinh d, chieu dai L, rai a cao h xuing AT = ^mi(vi - uj (vj -i- Ul) + -nia(vj - u,) (v, - uj) ,je CO khoi luong m^, xae dinh gia tic Ion nhdt , m , , Ciia vat rai? Vi: vi-ui = (I-t-k)^^(vi-V2); v2-u2 = -Ci+k)^7^Cvi-v2) 2tB,+m,'- '^ '^ Mat khac: ui - ui = - k(vi - vj) Gpi V| vau, la van toe ciia vat m, trudc liic va cham va sau va cham Cho rang nin co khoi lugng m^ la vo cung lan va co ciing tuyet dii Ta co: Chung ta nhan dugc: , \ c / ^ • m,(u,-v,)=-S (a)va u, kv, (b) ^^=I^'^''Xv.-v:)[v,-v:-i(v.-v:)].l^(l.k=)(vi^v.)^ Thay (b) vao (a) ta dugc: Trong truang hgp va cham mim, k=^0, ta - AT i_!5i!»w ^2 co:AT = ^ - (vi — V2r S=m,v,(l+k) (2.1) Bft^ + m^ Neu va cham hoan toan dan hii, k^ I, thi: AT = XT u~ 1' *_ L ^ Nghia la va cham hoan toan dan hoi, dgng nang ciia ca he khong bi mit di - Tinh dp bien dang ciia vat va cham m : Vat nang m, co dang hinh tru duong kinh d, dai L, ta tinh dupe biin dang tinh qua cong thiic siic ben vat lieu: pi Bay gio ta xet tnicmg hgp Vj=0, tiic vat thii nhfe va cham vao vat thii hai ban i&n Trong do, P: Trong Imjrng vat nang; E: diing yen, liic do: Mo dun dan hoi vat lieu; F: Tiet dien ngang ciia (vat nang) ' ^ • ^ = \ ^ ^ (1 - '''>''>=;;;?iz