Proceedings in Mnufcturing Systems, Volume 9, Issue 4, 2014, 239 244 ISSN 2067-9238 CAD-CAE IMPLEMENTATION IN CARGO SECURING SYSTEMS TESTING Ion-Tieriu GIURGIU 1,*, Petru ROȘCA 2, Iulin-Florin PANĂ 3 1) PhD student, Fculty of Engineering nd Mngement of Technologicl Systems, University Politehnic of Buchrest, Romni 2) Dipl. Engineer, Militry Equipement nd Technologies Reserch Agency, Clinceni, Romni 3) PhD student, Militry Equipement nd Technologies Reserch Agency, Clinceni, Romni Astrct: The pper presents comprtive nlysis etween numericl simultions performed in ANSYS softwre nd the results otined in rel dynmic tests in order to oserve the ehvior of crgo securing system. After sttisticl nlysis it cn e noticed tht the numer of rod csulties is higher when discussing out hevy goods vehicle (HGV) comprtive to pssenger vehicles. And one of the min resons for ccidents in trffic is the rollover effect cused y the incorrect securing of the lod disposed on truck pltform. The suject of the nlysis is 6 6 militry truck, dpted to crry onto its chssis specil pltform, secured with typicl connections due to the complexity of the entire ssemly. Both theoreticl nd prcticl informtion regrding the testing procedures re presented. The otined results re lso nlyzed nd the descried methods could e useful for vehicle testing engineers in order to predict the possile filures during rel testing. Key words: crgo securing, FEM, rking, simultion, testing procedures, vehicle stility. 1. INTRODUCTION 1 Nowdys, the demnd of the society on the trffic sfety is permnently incresing ecuse of the growing numer of the vehicles ll round the world. It is ovious tht trnsporttion infrstructure cnnot keep up with the rising numer of vehicles so other sfety mesures need to e considered. One of the most importnt issues relted to trffic sfety is the presence of hevy vehicles on pulic rods: trucks, rod tnkers, trilers, uses, militry vehicles, specil dpted vehicles nd so on. According to [1], sttistics show tht ccidents relted to hevy goods vehicle (HGV) re more dngerous thn those of pssenger vehicles. Even if they constitute only 3% of vehicles in trffic, hevy vehicles re involved in 10% of ccidents with ftlities. Furthermore, the ftlity rte is twice s high when HGV is implied. One of the most frequent ccidents is represented y rollover (20%) nd cuses significnt dmges to the vehicles nd injuries to its driver nd pssengers. For etter presenttion of this issue, we hve nlyzed sttisticl relese from 2012, regrding rod csulties in Gret Britin [2]. As it cn e seen in Fig. 1 etween 2007 nd 2011, seven times more goods vehicle occupnts were killed thn us nd coch occupnts in trffic ccidents. Figure 2 presents the sitution of seriously injured peoples in rod csulties, where the verge vlue is 1.5 higher when tlking out goods vehicle occupnts. Though, we cn notice tht in this time intervl, the overll numer of rod csulties is decresing. The min reson for this phenomenon could e represented y the permnent progress in utomotives nd the new technologies pplied on this type of vehicles in order to increse trnsporttion sfety. Here re some possile cuses of hevy vehicles impliction in trffic ccidents: overloded mss; incorrect disposl of the lod (see Fig. 3); excessive speed; dmged tires, suspension, or rking systems; Fig. 1. Sttistic of killed peoples in ccidents in Gret Britin (2007 2011). * Corresponding uthor: University Politehnic of Buchrest, 313 Spliul Independentei Avenue, Buchrest 6, Romni Tel.: 0040 741 125 180; E-mil dresses: giurgiutieriu@yhoo.com (T. Giurgiu), prosc@cttm.ro (P. Roșc), fciortn@cttm.ro (F. Pnă) Fig. 2. Sttistic of seriously injured peoples in ccidents in Gret Britin (2007 2011).
240 T. Giurgiu, P. Roșc nd F. Pnă / Proceedings in Mnufcturing Systems, Vol. 9, Iss. 4, 2014 / 239 244 Fig. 3. Methods of disposing the lod on truck pltform. indequte crgo securing systems; trffic congestions; overtking mneuvers; wether conditions; d rod infrstructure; This pper min suject is concentrted on crgo sfety issue, especilly on finding lterntive solutions for verifying the conformity of specil securing systems dpted on trucks designed for pulic trnsporttion. 2. GENERAL REGULATION Nowdys, ntionl regultions, stndrds nd guidelines hve een dopted ll over the world ecuse of the incresing numer of truck ccidents which cn e ttriuted to indequte crgo securing. However, even if the rules content nd scope slightly differ, most of them require tht crgo securing systems should e cple of withstnding the forces ssocited with following three decelertions/ccelertions, pplied seprtely: 0.8 g decelertion in the forwrd direction; 0.5 g ccelertion in the rerwrd direction; 0.5 g ccelertion in lterl direction. The first performnce requirement ws estlished tking into ccount the force exerted y the crgo towrds the front of the vehicle during full rking [3, 4]. On the other hnd, in ccordnce with 71/320/EEC [5], the performnce of rking systems for vehicles from N ctegory (vehicles used for the crrige of goods) is considered dequte if: the men fully developed decelertion is greter thn 0.5 g (type 0 test with engine disconnected); the men fully developed decelertion is greter thn 0.4 g (type 0 test with engine connected). However, even if vehicle is certified to circulte on pulic rods (EC type-pprovl certificte), it is possile not to rech 0.8 g decelertion. This is not n impediment though in the following context: crgo securing equipments re lwys uilt nd chosen in complince with relevnt stndrds nd guidelines. For exmple, Crgo Securement Rules [4] stipultes: Generlly, motor crriers re not required to conduct testing of crgo securing systems to determine complince with the performnce requirements. The new rules explicitly stte tht crgo immoilized or secured in ccordnce with the generl securing rules, or the commodity-specific rules, re considered to meet the performnce criteri. ; stndrd vehicles odies (side, front nd rer wlls) nd reinforced vehicles odies respect the sic requirements estlished in EN 12642 [6] nd the verifiction of conformity to this stndrd is provided y sttic testing. The difficulty ppers when specil chrge disposed o truck pltform should e secured with specific elements only, different from the stndrdized ones nd the vehicle structure differs from the models presented in EN 12642 [6]. Therefore, this pper presents method of verifying if specil securing system is cple of withstnding the force ssocited with 0.8 g decelertion in the forwrd direction, even if the vehicle is not cple of such decelertion. EN 12642 clims tht the ptitude for specil crgo should generlly e proved y driving tests nd if the vehicle rkes y themselves re unle to provide the necessry rking decelertion of 0.8 g the required decelertion shll e chieved e.g. y dding complementry rking device independent of the trck condition. Becuse the lst condition is difficult to e chieved, we propose tht the conformity verifiction to e relized through comined method: dynmic driving tests nd clcultion/simultions, oth ccepted y EN 12642. 2. VERIFICATION OF CONFORMITY METHOD The method consists in performing dynmic driving tests specified in nnex B, EN 12642 Testing rke decelertion in longitudinl direction, except the 0.8 g decelertion vlue. The vehicle is rking with mximum intensity, mesuring not only the decelertion ut lso speed nd other prmeters tht descrie the securing systems elements ehvior. In prllel, the computtionl model is relized, sed on geometricl model nd using finite element method (FEM) for the vehicle frme, securing equipments nd the lod. Hving the mesured decelertion, simultion of the entire ssemly will e performed in ANSYS in order to determine the deformtions nd equivlent stress decelertion method. The purpose of this procedure is to vlidte the computtionl model. If the results re fvorle, nother simultion should e performed for
T. Giurgiu, P. Roșc nd F. Pnă / Proceedings in Mnufcturing Systems, Vol. 9, Iss. 4, 2014 / 239 244 241 Fig. 4. Securing in longitudinl direction [7]: locking method: 1 centre of grvity; 2 lod; 3 locking device. Fig. 5. Vehicle frme nd pltform ssemly. vlue of decelertion of 0.8 g in order to verify if the crgo securing equipments re cple or not of withstnding the force ssocited to this vlue of decelertion in the forwrd direction. If crgo model is too complex, the method of clculting securing forces for lod restrint tht pper on the locking devices cn e used, s in [7] (Fig. 4). Blocking force in the longitudinl direction is clculted with the eqution elow: F B ( C µ c ) m g =, (1) x where: F B locking force; m the mss of the lod to e secured; g the grvittionl ccelertion; c x the longitudinl ccelertion coefficient; c z the verticl ccelertion coefficient; µ d coefficient of friction for dynmic friction. Using force F B vlue from eqution (1), locl simultion will e performed in ANSYS, following the sme steps previously presented force method. d z Lptop Fig. 6. Distnce sensor position. 3. CASE STUDY A cse study hs een developed in order to present the ccurcy of crgo securing equipments verifiction y pplying driving tests nd simultions in ANSYS. It ws chosen truck tht cnnot chieve the decelertion of 0.8 g ut it hs type-pprovl certificte. This sitution is frequently occurred ecuse typicl loded vehicle would not e expected to chieve decelertion greter thn 0.6 g on dry rod [4]. The truck frme (1) ws specilly dpted to crry pltform (2) with different equipments on it. The locking system (3) for crgo securing in longitudinl direction consists in pd with olt (4) element fixed on n ngle iron (5) welded to vehicle frme (see Figs. 5 nd 6). 3.1. Dynmic driving test A dynmic driving test ws performed, s specified in nnex B, EN 12642 "testing rke decelertion in longitudinl direction". To mesure the prmeters of interest, VBOX 3i dt logging system with n inertil mesurement unit IMU 02 ws used (see Fig. 7.). As it concerns the simultions on virtul model, dt cquisition ws needed regrding the deformtion of n element from the securing system. Thus IL-600 Keyence distnce sensor (6) with nlog output ws mounted in front of the ngle iron, with the lser point (7) t 10 mm ellow the upper mrgin s it cn e seen in Fig. 6. Fig. 7. VBOX 3i dt logging system configurtion. At the rking test (Fig. 8) n verge vlue of decelertion X_Accel = 0.43 g ws otined during one second intervl (1.5 2.5 s, see the highlighted zone), with minor influences given y pitching oscilltions verge vlue of Z_Accel is 0.997 g. The verge distnce etween sensor nd ngle iron is 255.7 mm, with 0.401 mm lower thn in vehicle sttic position. For these vlues, there were no permnent deformtions on crgo securing equipments or on the vehicle frme. 3.2. ANSYS simultion On 3D geometric model severl simultions were performed using ANSYS softwre in order to nlyze the ehvior of securing elements in longitudinl direction during decelertion similr to rel rking tests. As the studied phenomen s durtion is only 1 second, sttic nlysis is enough to descrie wht hppens. The mterils used for the simultions hve liner ehvior: the mjority of the pieces re mde of S235 steel with 235 MP yield stress, except the olts tht re mde of steel with 800 MP yield stress. The simultions purpose is to otin the vlues of equivlent stress, totl deformtions nd sfety fctor. A) Decelertion method. In this cse, the force to e pplied ws generted from vlue of decelertion of
242 T. Giurgiu, P. Roșc nd F. Pnă / Proceedings in Mnufcturing Systems, Vol. 9, Iss. 4, 2014 / 239 244 Fig. 8. Full rking tests on level rod. Fig. 9. Decelertion method: sttic structurl representtion; ngle iron deformtion. 0.43 g, otined t rel rking test. Becuse of the complexity of the equipments disposed on the pltform they were ll converted to point mss. Figure 9 presents the sttic structurl representtion () nd the ngle iron deformtion (). According to simultions, the otined deformtion (in elstic domin) is out 0.402 mm in the interest zone (10 mm ellow the upper mrgin of the ngle iron). Fig. 10. Force method: sttic structurl representtion; ngle iron deformtion. B) Force method. In this second cse, the forces to e pplied were clculted ccording to EN 12195-1, tking in considertion vlue of 0.43 for c x nd vlue of 0.1 for µ d. Both the pltform nd the equipments disposed on it were converted to point mss, mintining the rel support surfces. The point mss definition is required ecuse of the influence of vehicles frme deformtion under lod ction. This method s dvntge is the simpli-
T. Giurgiu, P. Roșc nd F. Pnă / Proceedings in Mnufcturing Systems, Vol. 9, Iss. 4, 2014 / 239 244 243 fiction of the 3D model nd ANSYS simultion s well. Figure 10 presents the sttic structurl representtion () nd the ngle iron deformtion (). According to simultions, the otined deformtion (in elstic domin) is out 0.419 mm in the interest zone (10 mm ellow the upper mrgin of the ngle iron). 3.3. Model vlidtion Both previously mentioned methods provided close results to those otined in rel rking tests for ngle iron deformtion. However, decelertion method is more pproprite ecuse in this cse the simultion is pplied to the entire ssemly in comprison to force method where there re two ctions in prllel, nmely the pltform mss on the vehicle frme nd forces influence on the securing system in longitudinl direction. Therefore, the nlyzed model in ANSYS (especilly decelertion method) is dequte nd cn e used to vlidte the cse of 0.8 g decelertion (see Fig. 11), where, t the level of studied ngle iron, the interest prmeters hve the following vlues: mximum deformtion: 0.57 mm; mximum equivlent stress: 92.75 MP; minimum sfety fctor: 2.69. As it concerns the entire ssemly (see Fig. 12), the otined results re lso stisfying: mximum deformtion: 8.42 mm; mximum equivlent stress: 187 MP; minimum sfety fctor: 1.59. Anlyzing the previously mentioned vlues, it cn e noticed tht the mximum equivlent stress does not rech yield stress vlue (235 MP) so it cn e considered tht ll the deformtions re in elstic domin. 4. CONCLUSIONS Most sttes hve legl requirements regrding the cpility of crgo securing systems to withstnd the forces ssocited with 0.8 g decelertion in forwrd direction. Detils out restrining methods nd systems re found in EN 12195-1 nd EN 12642. However, none c Fig. 11. Simultions results for 0.8 g decelertion over the ngle iron: Totl deformtion; Equivlent stress; c Sfety fctor. c Fig. 12. Simultions results for 0.8 g decelertion over the entire ssemly: Totl deformtion; Equivlent stress; c Sfety fctor.
244 T. Giurgiu, P. Roșc nd F. Pnă / Proceedings in Mnufcturing Systems, Vol. 9, Iss. 4, 2014 / 239 244 of these stndrds refers to the specil sitution when the vehicle is not cple to rech 0.8 g decelertion nd the crgo securing systems re not stndrdized (locking cse, especilly). This pper provides method to prove the performnce criteri tht comine dynmic driving test with simultion method in ANSYS. The first step ws to vlidte virtul model y rel dynmic driving tests for the vlue of decelertion provided y the nlyzed vehicle in this cse smller thn 0.8 g. Compring the mesurements mde in rel rking driving test for 0.43 g decelertion, with the simultions on the developed model, it cn e noticed tht the results re stisfying. Therefore, the proposed model cn e vlidted nd fterwrds the cpility of meeting the performnce criteri for 0.8 g decelertion is verified using the sme principles. All vehicle structures, systems, prts nd components used to secure crgo must e in proper working order when used to perform tht function with no dmged or wekened components tht could dversely ffect their performnce. Therefore, in ANSYS smller vlue thn the yield stress must e otined for the equivlent stress nd t lest 1.5 for the sfety fctor. The cse study presented in this pper demonstrtes tht this method is vile. Moreover, comprison etween 2 methods of generting forces ws performed in ANSYS: y pplying decelertion (decelertion method); y pplying forces clculted ccording to EN 12195-1 (force method). As expected, the first method provides etter results y perceiving the components s n entire ssemly. The second one, though, presents the dvntge of simplifying the 3D model nd ANSYS simultion y reducing the entire lod to point mss. Future reserch could provide even etter results if creting model in Multi-Body System (MBS) softwre nd performing dynmic simultions to nlyze the ehvior of crgo securing systems when rking. ACKNOWLEDGEMENTS: This work hs een funded y the Sectoril Opertionl Progrmme Humn Resources Development 2007 2013 of the Ministry of Europen Funds through the Finncil Agreement POSDRU/159/1.5/S/138963. REFERENCES [1] Y. Sellmi, H. Imine, B. Jco, F. Bernrdin, J.C. Cdiou, Rollover risk prevention of hevy vehicles y reliilitysed nlysis, Proceedings of the Interntionl Conference on Hevy Vehicles HVPris 2008, Eds: B. Jco, E. O Brien, P. Nordengen, A. O Connor, Mohmed Bouteldj, Pris, My 2008. [2] Reported Rod Csulties in Gret Britin: Min Results 2011, Deprtment for Trnsport, 28 June 2012, https://www.gov.uk/government/uplods/ system/uplods/ttchment_dt/file/9066/rep orted-rod-csulties-in-gret-ritin-minresults-2011.pdf. [3] *** Europen Best Prctice Guidelines on Crgo Securing for Rod Trnsport. [4] *** Crgo Securement Rules, Federl Motor Crrier Sfety Administrtion, U.S. Deprtment of Trnsporttion, Puliction No.: MC-P/PSV-04-001. [5] *** COUNCIL DIRECTIVE of 26 July 1971 on the pproximtion of the lws of the Memer Sttes relting to the rking devices of certin ctegories of motor vehicles nd of their trilers (71/320/EEC). [6] *** Europen Stndrd EN 12642, Securing of crgo on rod vehicles. Body structure of commercil vehicles. Minimum requirements. [7] *** Europen Stndrd EN 12195-1 Lod restrint ssemlies on rod vehicles. Sfety. Prt 1: Clcultion of lshing forces. [8] *** http://www.velocityox.co.uk/index.php/compo -nent/content/rticle/39-pplictions/129- costdown-testing-equipment.