Redesigning& Optimization of Conveyor Pulley

Transcription

1 Intrnational Enginring Rsarch Journal (IERJ) Spcial Issu 2 Pag , 2015, ISSN ISSN Rdsigning& Optimization of Convyor Pully #1 Prasad C. Pol, #2 S. M. Jadhav 1 prasadpol@ymail.com 2 sainand.jadhav@sinhgad.du #1 M.E. (Mchanical Dsign Enginr),SavitribaiPhul Pun Univrsity, Pun, India #2 Assistant Profssor, Dpartmnt of Mchanical Enginring, NBN Sinhgad School Of Enginring,Pun, India. ABSTRACT Convyor pully is widly usd in th ara of matrial handling quipmnt fild. Pully is hart of th bulk mining matrial handling. Th main componnts of convyor pully ar shaft, drum or shll, nd disk or diaphragm plats, locking lmnts, nd disk, lagging and baring assmblis. Sinc th strsss and dflctions of its parts ar dpnds on ach othr, an analysis of pully assmbly is mandatory for rliabl pully dsign. Dsigning pully of this kind rquirs complx calculations of all blt tnsions and loads in static conditions. This work will considr assumptions on load variations around its priphry & along th pully fac-width, axial load, slfwight, dad wight and angular vlocity. This papr attmpts to analyz stady stat dsign charactristics for rquird capacity of convyor pully. Th optimization of th dsign is don through numbr of itration by dsigning problm paramtrically. ARTICLE INFO Articl History Rcivd :18 th Novmbr 2015 Rcivd in rvisd form : 19 th Novmbr 2015 Accptd : 21 st Novmbr, 2015 Publishd onlin : 22 nd Novmbr 2015 Kywords Shaft, Drum, End disk, Dsign Optimization, ANSYS. I. INTRODUCTION Th convyor pully is thr componnt assmbly of shaft, locking dvic and nd disk wldd with drum. It is a flat blt pully which is majorly usd for long distanc transportation of bulk matrials.th pullys ar widly usd in mining sctor, cmnt industry as wll as sugar industry. Pully and blt ar thmain componnts of th whol bulk matrial handling systm whosfailur will caus substantial downtim as wll as damag to othr structur.th stability of cylindrical drum is vry important S. P. Das and M.C. Pal considrd th drum buckling undr variabl loading. Thy considrd th buckling of drum undr xponntial load but not considr th variation along pully fac width.m. Ravikumar, Avijit Chattopadhyay considrd th both variation that is xponntial and along th fac width. Thy analys th pully as intgral that is pully as whol.th studis using classical analytical approachs hav considrd th pully in parts as wll as a singl structur. In this work, computation is asy, as a clos form solution xists and it taks modrat xcution tim. But th solutions nar th connction rgion btwn th parts cannot b accurat bcaus of th approximation in trating th lastic coupling btwn thm. Spcially, thir displacmnts ar not coupld at thir connctions. This lads to significant rrors in th strss and strain filds about th connctors. Also, ths mthods cannot b xtndd to complx shaps as thos of pullys having taprd wbs or providd with tapr-lock arrangmnts. On th contrary, th finit lmnt mthod, though a littl tdious and tim consuming, offrs a practical solution tchniqu. Ma Xingguo Wang Yanling, Zhou Mingyu givs th optimal structur dsign for blt pully but thy don t uss th load variation i.. thy considrd linar blt load.as it is hart of th systm, th fficincy of systm working dpnds on how fficintly th pully is working. So, th xcssiv strngth and stiffnss which corrsponds to th xcssiv wight of th pully is not ncssary. Pully with th xcssiv factor of safty is not rquird as it also incrass th ovrall cost of th projct.so, to dcras th wight and cost of projct th pully should b optimizd kping th dflction and strss in th componnt within th prscribd limit. A. Mallikarjuna Rao, G S S V Sursh, Priyadarshini Ddos th thortical calculation and optimization of convyor pully using FEA but considrd th xponntial variation only. 2015, IERJ All Rights Rsrvd Pag 1

2 Intrnational Enginring Rsarch Journal (IERJ) Spcial Issu 2 Pag , 2015, ISSN I. CONVEYOR PULLEY A. Convyor Pully Cut Sction Fig.1. shows th cut sction of th convyor pully. Th pully has th constant cross sction as shown. So, w can analys th pully as axisymmtric modl considring th ¼ modl for th analysis. It minimizs th ffort of crating th whol modl and also savs th solution tim. But actual forcs acting on th pully is much mor svr than th uniform forcs considrd in axisymmtric analysis. But, axisymmtric analysis is possibl only whn modl as wll as th loads coming on it ar uniform.in this work w ar considring th load variation so analysis of th whol modl is ncssary in this cas. Fig.2. Ara Modl of Pully Aftr rotating fig.2 th whol modl with mshing is gnratd.fig.3 shows th mshd modl. Fig.1. Pully Cut Sction B. Modlling of Convyor Pully Though th structur of th pully looks simpl th whol modlling of it is difficult. As th structurs of pully ar hug th modlling is to b don kping in mind that to minimiz th numbr of nods and lmnt to b cratd.for it th mshing should b don by using quad lmnt rathr than tria lmnt as thy giv th minimum no of nods and lmnt. As w ar going to optimiz th pully which is an itrativ procss by varying diffrnt paramtrs, chcking th strngth and stability aftr changing th paramtr is ncssary.so, th paramtric modlling of pully bcoms important. In th modlvarious gomtric paramtrs such as radius, lngth at diffrnt location for shaft,locking dvic, nd disk, drum, lngth of baring span, thicknss of drum tc. ar dfind.th advantag of paramtric modlling is that whn w chang any dimnsional paramtr, th whol modl gts updatd automatically. For modlling and FEA analysis ANSYSis usd.for paramtric modlling th cod is writtn in notpad which can dirctly run in ANSYS APDL. Firstly th ara modl is cratd & mshd with dummy msh by lmnt msh200 &kyopt(1)=7. Thnth Solid modl and brick msh is cratd by using solid lmnt and by rotating ara modl. Fig.3. Brick Mshd Pully Modl II. FINITE ELEMENT ANALYSIS Thr arsingl or multipl loads acting on th pully at a tim. So, analysis for a singl load as wll as combind loads is ncssary. A. Load Cass Considrd for Analysis 1) Pully Dadwight: It is th load coming on th pully du to its slf-wight which acts at CG of th pully. 2) Ovrhung Load: It is th load coming on th pully du to garing assmbly. 3) Axial load: It is takn som prcntag (narly 10 to 15 %) of th maximum load acting on th pully whr blt is in contact with th drum. 4) Blt Tnsion:It is th most distorting forc acting on a pully. This forc varis xponntially along th circumfrnc of pully and sinusoidal along pully fac width. Th blt tnsion acts on drum whr blt is in contact with drum. 5) Cntrifugal Forc: It is th inrtia forc acting on pully du to th rotational spd of th pully. It acts at CG of pully. 2015, IERJ All Rights Rsrvd Pag 2

3 Intrnational Enginring Rsarch Journal (IERJ) Spcial Issu 2 Pag , 2015, ISSN B. Constraint To obtain ANSYS rsults from th modl thr should not b any rigid body motion i.. th modl should b sufficintly constraind. As th pully is supportd on two barings th diffrnt constraints ar applid at baring surfacs. Baring at non driv nd ar givn displacmnt constraints in y and z dirction and at driv sid baring alldisplacmnt constraints ar applid. C. Contact Considration For th modl to prform as ralistic as possibl,contacts ar dfind aftr modl cration. As contacts ar usd in th modl th analysis of modl bcoms nonlinar. Four Contact pairs ar dfind i.. two pairs btwn shaft and locking dvic and two pairs btwn locking dvic and nd disc.as locking dvic is not wldd to shaft as wll as nd disk it should not b glud dirctly in ANSYS. If w gluit togthr it will prform as wldd connction and w ar unabl to calculat th contact strss btwn shaft & locking dvic pair and locking dvic &nd disk pair. It is vry important to calculat contact strss btwn contact pair, as it is frictional contact btwn thm which transfrs th torqu & powr applid by driving motor.som Paramtrs usd for modlling and analysis ar givn in tabl I TABLE I Structural Paramtr paramtr symbol Valu Blt width lblt 1400m m Blt spd 1 m/s Pully fac width lpw 1600m m Blt tnsion T1 234KN Blt tnsion T2 65KN Pully wrap angl 210 o Drum thicknss thdrum 16mm Shaft radius r 112mm End disk radius r 145mm Shaft lngth ls 2702m m Shaft radius at baring mount rb 90mm Baring span bspan 204mm Shaft radius at locking dvic rh 110mm As pr considrd loads, boundary condition analysis is don in ANSYS. Th maximum strss is coming on drum which shown in fig.4 & fig.8 which is kg/mm 2 nar outskirt of th drum. Th fig.5 givs th maximum strss for shaft which is 4.96 kg/mm 2 occurs at baring constraint. Th maximum strss in nd disk is 5.65 kg/mm 2 which occurs nar wld as shown in fig.7. Th maximum strss & dflction valus ar summarizd in Tabl II. TABLE III Th dflction & strss of ach componnt Componnt Dflction Strss mm Kg/mm 2 Shaft Locking Dvic Hub Drum Fig.4. von miss Strss in Pully Fig.5. von miss Strss in shaft Fig.6. von miss Strss in locking dvic 2015, IERJ All Rights Rsrvd Pag 3

4 Intrnational Enginring Rsarch Journal (IERJ) Spcial Issu 2 Pag , 2015, ISSN Fig.7. von miss Strss in nd disc Fig.10.Contact prssur btwn contact pairs III. OPTIMIZATION CONSIDERATION Optimum mans to mt all spcifid rquirmnt at minimum xpns. Optimization mans to rduc th wight, volum, surfac ara, path to follow or incras th fficincy of ngin, transmission tc. In optimization modl basically thr ar thr variabls which ar dsign variabl, stat variabl & objctiv function. Fig.8. von miss Strss in drum D. Dsign Variabl(DV) Ths ar indpndnt quantitis which ar varid to achiv th optimum dsign. Thortically all th gomtric paramtrs such as lngth, radius tc. can b tratd b as DV, but in practic paramtr which causs th sufficint chang in objctiv function is slctd as DV. In th problm w ar considring th shaft radius(r) & drum thicknss (thdrum) as DV. E. Stat Variabl(SV) Stat variabls ar th variabls that constraint th dsign problm. In gnral strss,dflction in componnt, tmpratur, flow rat, frquncy tc. ar th stat variabls.in th problm w ar considring th dflction & strss in th pully acts as a SV. F. Objctiv Function It is a dpndnt variabl which is to b optimizd. Our problm is to minimiz th wight. If w us th sam matrial for ach componnt thn th wight and volum can b intrrlatd. So, our problm of minimizing wight bcoms problm of minimizing volum of convyor pully. Fig.9 Contact Status btwn four contact pair IV. OPTIMIZATION RESULTS OF ANALYSIS Th ANSYS program offrs two optimization mthods to accommodat a wid rang of optimization problms. Th sub problm approximation mthod is an advancd zroordr mthod that can b fficintly applid to most nginring problms. Th first ordr mthod is basd on dsign snsitivitis and is mor suitabl for problms that rquir high accuracy.for both th sub problm approximation and first ordr mthods, th program prforms a sris of analysis-valuation-modification cycls. That is, an analysis of th initial dsign is prformd, th 2015, IERJ All Rights Rsrvd Pag 4

5 Intrnational Enginring Rsarch Journal (IERJ) Spcial Issu 2 Pag , 2015, ISSN rsults ar valuatd against spcifid dsign critria, and th dsign is modifid as ncssary. This procss is rpatd until all spcifid critria ar mt. Th optimization loop is run in ANSYS with th rlvant commands for dfining stat variabl, dsign variabl, objctiv function and thir rang btwn which that variabl is going to varid during optimization loop. Th maximum numbr of itration dfind in loop ar tn. TABLE IIIII Optimization Rsult St no. Rgion 1 Fasibl 2 Fasibl 3 Fasibl 4 Fasibl 5* Fasibl 6 Fasibl 7 Fasibl 8 Infasi bl 9 Infasi bl Shaft radiu s mm Drum thickns s mm Strs s Kg/m m Disp. sum mm Fig.12Variation of drum thicknss vs itration no. Fig.13 Variation of quivalnt strss vs itration no. Th optimization rsult valu of shaft diamtr, drum thicknss, strss and dfction at ach itration is summarizd in Tabl III. Fig11 to Fig.15 givs th variation of dsign variabl, stat variabl and objctiv function with rspct to itration numbr. Th plot shown fig.11 givs th ida how th shaft radius varis with ach itration. Th fig.12 shows th variation of drum thicknss with ach itration as wll as th lowr and uppr limit of rang. Th fig.13 xplains th bhavior of quivalnt strss with rspct to itration numbr. Fig.11Variation of shaft radius vs itration no. Fig.14 Variation of displacmnt sum vs itration no. 2015, IERJ All Rights Rsrvd Pag 5

6 Intrnational Enginring Rsarch Journal (IERJ) Spcial Issu 2 Pag , 2015, ISSN Fig.15 Variation of total volum vs itration no. Th graph shown fig.14 givs th ida how th displacmnt sum incrass with itration.th fig.15 shows how th objctiv function i.. total volum rducs with ach itration. V. CONCLUSIONS Th abov ANSYS rsults shows that th total volum of pully is rducd by 9.3% which ultimatly rduc th wight of th pully. Chang in quivalnt strss in optimizd & pr optimizd pully is vry lss whras th displacmnt sum is incrasd by 9%. Aftr optimization optimal valu of shaft diamtr is 100mm,drum thicknss is 14.29mm approximatd to 14.5mm.Th Wight of optimizd pully coms out to b 1439 kg. Pully Shll", Computrs & Structurs Vol. 35, No. 3, [6] S. P. Das and M. C. Pal," Strsss and Dformations of A Convyor Powr Pully Shll undr Exponntial Blt Tnsions", Computrs & Structurs Vol. 35, No. 3, [7] Lu Hong-Shng," Shll Strngth of Convyor Blt Pullys: Thory and Dsign" Lu Hong-Int. J. Mch. Sci. Vol. 30, No. 5, [8] Ma Xingguo Wang Yanling, Zhou Mingyu, "An Optimal Structur Dsigning Of Blt Pully", Third Intrnational Confrnc on Intllignt Ntworks and Intllignt Systms, [9] Vinod M. Bansod, Abhay A. Utpat, Fatigu Lif Prdiction Of A Butt Wld Joint In A Drum Pully Assmbly Using Non-Linar Static Structural Analysis,Intrnational Journal of Mchanical and Production Enginring (IJMPE) ISSN , Vol-1, Iss-1, [10] Trry J King, Th Function and Mchanism of Convyor Pully Drums, Intrnational Matrial Handling Confrnc BELTCON 3. [11] Allan Lill, Convyor Pully Dsign, Intrnational Matrial Handling Confrnc. [12] Tim Wll, Effct of Driv Assmbly Ovrhung loads on Blt convyor and pully Dsign. [13] ANSYS Mchanical APDL Basic Analysis Guid. [14] ANSYS Mchanical APDL Command Rfrnc. ACKNOWLEDGMENT Th author is vry thankful toprof. S. M.Jadhav,Prof.Dr.S.Y.Gajjalfor thir mthodological support and frank opinions about th topic.th author dply indbtd to parnts for thir inspiration, constant support. REFERENCES [1] J.A. Martins, I. Kovsdy, I. Frrira, "Fractur Analysis of Collapsd Havy-Duty Pully In A Long- Distanc Continuous Convyors Application", Scinc Dirct Enginring Failur Analysis, 16 (2009). [2] Ch. Affoltr, G. Piskoty, R. Kollr, M. Zgraggn, T.F. Rutti, "Fatigu Failur Analysis In Th Shll Of A Convyor Drum", Scinc Dirct Enginring 14 (2007). [3] A. Mallikarjuna Rao, G S S V Sursh, Priyadarshini D, "Altrnat Dsign and Optimization Of Convyor Pully Using Finit Elmnt Analysis", Intrnational Journal of Enginring Rsarch & Tchnology (IJERT), Vol. 1 Issu 7, Sptmbr [4] M. Ravikumar, Avijit Chattopadhyay, "Intgral Analysis Of Convyor Pully Using Finit Elmnt Mthod", Computrs and Structurs 71, (1999). [5] N. Siva Prasad and RadhaSarma, "A Finit Elmnt Analysis For Th Dsign Of A Convyor 2015, IERJ All Rights Rsrvd Pag 6