An Experimental Study about Tractive Performance of Tracked Vehicle on Deep-sea Soft Sediment Based on Design of Experiment Using Orthogonal Array

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(1)Ocean and Polar Research. Vol. 26(2):333-339. June 2004. Article. çvVR þê³»ö ~ £æ>Ï ZÊêNï~ Ò9Ëö & þ . R«> Ás 5 ÁB;Ö Á\ 1*. 1. 1. 2. ·ö ·B*ÊR¦ &*7 .9ÖÚ Ò* 23^ ·&v 8ê¦ (133-791) *Þ 9ÿ ¯ÿ 17. 1. (305-600). 2. An Experimental Study about Tractive Performance of Tracked Vehicle on Deep-sea Soft Sediment Based on Design of Experiment Using Orthogonal Array Jong-Su Choi1*, Sup Hong1, Hyung-Woo Kim1, and Tae Hee Lee2 1. Ocean Development System Laboratory, KORDI Yuseong P.O. Box 23, Daejeon 305-600, Korea 2 School of Mechanical Engineering, Hanyang University Seoul 133-791, Korea. Abstract : This paper is concerned with an experimental investigation about tractive performance of a tracked vehicle on extremely soft soil. A tracked vehicle model with principal dimensions of 0.9 m(L) × 0.75 m(B) × 0.4 m(H) and the weight of 167 kg was constructed with a pair of driving chain links driven by two AC-servo motors. The tracks are configured with detachable grousers with variable span. Deep seabed was simulated by means of bentonite-water mixture in a soil bin of 6.0 m(L) × 3.7 m(B) × 0.7 m(H). Slip of vehicle and driving torque of motor were measured with respect to experimental variables; grouser span, grouser chevron angle, driving speed, drawbar-pull weight, position of center-of-gravity and weight. L8 orthogonal array is adopted for DOE (Design Of Experiment). The effects of experiment variables on traction performance are evaluated.. þê³». $O9 æ>. ZÊêNï(tracked vehicle), çvVR(orthogonal arrays),. ¢Ö(grouser), Òþ(drawbar-pull test), Òã(slip), ÿÆJ\. Key words : (cohesive soil), (Design Of Experiment), (driving torque). 7ÊRf £ æ>*¢ ÿ~B 7>¶öj Îbº ÷7ÊR" ÷7B Z¢ çb ÇÊº ·7 \º

(2) %>¶öÏ j%ÊR~ ÷%ÊR ÊR, çöB *Ú *~¢ ÿÊB *Ú¢ BÚ~ j **~8 *~ >¯>î . öB J7 j º j ~º ç2Ñ b WB . ÷7ÊR f & £æ>çöB ÊR *Úö ÒKj B ~º "¯Ë~f Z¢ Îbº j÷Ë~ Ò j÷ *Corresponding author. E-mail : [email protected] 1. B. V.

(3) 334. Choi, J.-S. et al.. B Z¢ ·7ÊRb ÇÊº ÇÂË~ W> Ú ® . & £æ>Ï "¯Ë~~ V Jê¶òf B B 7ö ®º "¯Ë~ *ÖÎ~ ¦Ã¶ò¢ áV *~ & >¯>î . *Zf ?f 7>¶ö ª

(4) ®º & £ æ> *öB ·ë~º "¯Nï~ WËf £æ>~ * ;êö ôf 'Ëj Aº . ï·~ ¢ÒN-ã¢ Ê *Z (CCFZ)~ æ>Æ·f Ö 6OW , æ 10 cm ~öB &*;ê& 3~10 kPa &f º~ *;ê~ j¢ ¾æÚº "6ê& 2.7~ >Wj &æº ©b Ò>î (Chi et al. 1999). & £æ>Ï "¯Nïj BB~V *Bº æ> ~¢ ¢;ï ~ B~º ¦·WË(flotation)" N ï ÿö jº Ïª >Kj áV * "¯WË (trafficability)ö & ê ®º & jº~ . & £æ>Ï "¯Nï~ ãÖ ¦·WË {¢ * 7æ{j B~¢ ~, "¯WËj áV * Ïª ÒK {& ºB . 8¢B Êê 9f Z ÊêNï(tracked vehicle) & £æ> "¯ö &Ë ' ; ©b 6B . ZÊêNï~ "¯WËö &Bº ôf & >¯ >î . Dugoff and Ehrlick(1966)º &öB &:j. J~V * ZÊê; "¯NïÎö &~ Æ·> (water soil bin) þj >¯~& . Nuttall(1971)f &öB "¯~º ZÊêNï~ &BÒK(maximum net traction)j Vö Ò &æ G;O»b * 7'b ÖÂ > ®º Onö &~ þ ¢ > ¯~& . Muro(1983, 1988)º .£æ>*öB "¯~ º ZÊêNï~ ÒßWö &~ ~& . $, £ &æ> *¢ "¯~º ®ê&~ ÒßWö & ¢Ö& Î"¢ Ò~& . Dörfler(1992a, 1992b)º ÎÒB £æ>öB ZÊêNï~ ÒK(drawbarpull) þj >¯~& . Þ¿~ :ã Rö ¦O>Ú ®º ¢Ö&º Ò Kj Ã&B "¯Nï~ Òãj *º j . Î ÒB £æ> çöB ¢Ö&~ ;f ¸& ÒK " Òã~ö ~º 'ËKö & V.& >¯B : ® (Hong and Choi 2001). V.¢ :ûb þ ê³>î . ¢^öBº ãB' ÎN' "¯WË þ >¯j *B çvVR(orthogonal array)ö ~ þ ê³»j 'Ï~& . "¯WË þöº *" jÏ 5 K Ö ² º>V H^ö, ²~ þÅ>. þæ>ö & wßWj 2k > ®º ÎN'. þO» jº~ . çvVR þê³»f ÎN'. þj >¯ > ®ê ôf êæj & .. 2. þ J. Æ` & £æ>f ÊÆ¾Þf b~ bb(~ b b)j ÒÏ~ Æ ÚöB ÎÒ>î . Fig. 1f Æ~ Òêb "º~>º 3.7 m( )Ü6.0 m(^)Ü0.7 m(p ) ÆÚ bb~ *;ê ßWö Ò& >¯B : ® (Choi et al. 2002). Æ~ ¦³Ë~º v>Ë~, R;ÒË~, X-Y &N, ., *;ê êGË~ ® . v>Ë~º bb~ *;ê& ¢;~ê Ïª v> Úæ ê ~, R;ÒË~º v> ê æ á bb~ Rj ;Ò . X-Y&Nº v>Ë~f R;ÒË~¢ ÿÊB ''~ VËj >¯~º j>' j . .f NïÎj Æ Ú R«~ ²>~V * J~>î . *;ê êGË~º X-Y &N*ö ÷ Ò>Ú ö~º *~öB bb~ *;ê¢ êG~º j >¯ . bb~ >j¢ ;~ Æ Ú bb~ º~* ;ê(residual shear stress)& ¢;8b Fæ>² ~&. .. þ~ >¯ ç*ö êGB bbf ï &* ;ê 2.936 kPa" R&ÞN 0.034 kPa, ï º~* ;ê 2.160 kPa" R&ÞN 0.069 kPa, &*;êf º~*;ê~ j¢ ¾æÚº "6êº ï8 1.36" R&ÞN 0.028¢ º ©b êG>î . bb~ ;êº £æ>~ º~*;ê¢ Ï R ÎÒ>î . æ>" ?f Ö "6 *; ê ßWj ÎÒ~V *Bº bb~ JÂ z"; (consolidation)j jº~V H^ö, >'(conservative) £æ> "¯WË .Gj *~ æ> . º "6~æò º~*;ê¢ ¢~Êº ÎÒ O. Fig. 1. Soil bin containing cohesive soil of bentonitewater mixture..

(5) Experimental Study about Tractive Performance of Tracked Vehicle on Deep-sea Sediment. 335. Fig. 2. Tracked vehicle model. Fig. 4. Grouser height and span. Table 1. Specification of tracked vehicle model. Width of track Reference contact length Static average contact pressure Distance of tracks *Longitudinal center of gravity *Vertical center of gravity Diameter of idler wheel Diameter of sprocket Number of road wheel Grouser height Grouser span Grouser chevron angle *Longitudinal position of draw-bar pull *Vertical position draw-bar pull. Symbol Value Unit D 200 mm L 670 mm P 5.27 kPa B 550 mm Lcg 330 mm Hcg −22.3 mm r 147 mm S 100 mm Nrd 24 EA. Hg 38.1 mm Gp 38.1 mm o g 195 −121 mm Ld Hd 47.5 mm. *Positions are defined with respect to the center axis of rear sprockets.. Fig. 3. Grouser chevron angle.. »j j~& . B Þ/ :f ? æ>~ ï "6ê 2.7º bb~ "6ê 1.36ö j ~ v Vö . ¯Nï Î þj *~ JêÁB·B "¯Ë~ Îf Fig. 2f ?b "º¦~ ;ç 5 ~>º Fig. 3f Fig. 4 Ò Table 1ö ¾æÚî . "¯Nï Î~ &Û' ;~>º 0.9 m(^)Ü0.75 m( )Ü0.4 m(¸) .. "¯ ÒKj Î"'b áV * £æ> "¯ Nï Îf ²Ö Þ¿~ : ö â'; ;~ ¢Ö && ÚÖ>Ú ® (Fig. 2 ^). "¯Nï Î~ ßW" Ò·f r" ? . · ê ÿ; ZÊê Nï(Þ¿ , 0.2 m) · Ú-Ê*¢9 ÿ(²Ö êê ÿ) · AC-B ÎV ÿ 5 PCV> BÚ Ê · ' ÎV~ ÿK(Pw)f ÆJ(T) : 0.75 kW f 48 Nm · Þ¿~ &³ê(Vt) : 0.5 m/s · Z² : 167 kg ¢Ö& Rö æ>~ ¦O*ç(adhesion)f ZÊ.

(6) 336. Choi, J.-S. et al.. ê; Nï~ WËj &~ÊV H^ö ¦O*çj ² zÒ jº& ® . Fukagawa et al.(1998)º r* z + R &f ?f 6OW æ>öB ¦Oj 6² Êº j" Î"'¢º ©j BR~&, öB º ¦O*çj ²z~V * ¢Ö&~ Rj 50 µm vþ~ r*b z+~& . 3. ÒWË þ. þO» ÒWËþ(drawbar-pull test)f Fig. 5f ? >¯ >î . Ò~7(T)f 7ïb Ûö ÚÖ 7ï(2T)~ .>b "¯Nïö >ïb ·ÏB . H, Ò~7 f FÚ' K" F& >K~ Îj ¾æÞ . Fig. 6f ÒWËþ~ &j¢ î~ ÂBj V Òº "¯Nï Î;~ Òêj & . çL8Rö ~R þê³» Îv 4*~ Jêæ>f 2B~ ÚÏæ>& þæ> (experiment variables) F;>î . ¢Ö& *Ï, ¢ Ö& ãª', ^OË~ Z²7, NïZ²º Jê ö. Fig. 5. Schematic diagram for drawbar-pull experiment of tracked vehicle model.. ;ç" ~>¢ Ö;¢ Jêæ>(design variables) , Nï~ ³êf Ò~7f ·ë" &NB ÚÏ æ>(operation variables) . Nï~ "¯Òã" ÿÆJ& WË~B F>î. . "¯Òãf (1)ö ;~>Ú ® . Vt – Vg i = ---------------Vt. (1). VB V º Þ¿ ³ê¢ V º Nï~ ÿ³ê¢ '' ¾æÞ . Þ¿³êº Nï~ ÿÎVö ¦O>Ú ®º úzz¢ Ï~ êG>, ÿ³êº "¯Ò¢ *b ¾:bB êGB . ÿ ÆJº NïÎ~ Ê*9 ÿÎVö ·Ï~ º ¦~ö V¢B ²º>º /*~¢ :ûb G;> î . V¢B G;B ÿÆJöº NïÎ~ Vê' Ú¦ÿ &" æ>~ *>K 5 Ò~7ö ~ ¦ ÿ& þ >Ú ® . Î"'b þj >¯~ Ö"¢ Ò'b ª C~V *B '. þê³»(DOE, Design of Experiment)ö ~ þ >¯>Ú¢ . öB º çvV¢ Ï þê³»j Ï~& . *Ú' ßWj 2k~V * ' þæ>º 2>&j &æê J;~& . f ?f þæ> * »j ÒÏ ãÖ C 64²(2Ü2Ü2Ü2Ü2Ü2)~ þ jº~ . * » &; ±f Ö"¢ ÖÂ~º O »æò, jÏ" *j &b *V *B ¦ª. » 7 &æ çvV¢ Ï O»j ÒÏ~ V . $, ¦ª » * »ö &~º Ö "¢ áj > ®ºæ¢ ¦Ã~V *B º& þj >¯ ~ jv~& . öBº Table 2f ? çvV7 L j F ~ 8²~ þj >¯~ Ö"¢ ªC~& . $, 1 ²~ º& þj >¯~ çvV þê³»ö ~. B Ö" ~ ªCö ~ .G Ö"f jv ¦Ã~ & .. þæ>~ >&8j Ö; rº þ÷7V~ Jê 'Ï &Ë * ' º*f "¯NïÎ;ö B * &Ë º*¢ J~ >&j Ö;~& . ¢Ö & *Ïf V8 38 mmf ©~ 3V 114 mm ~ &b(Fig. 4 ^), ¢Ö& ãª'f −15 f 15 F ;~& (Fig. 3 ^). Nï ÿ³êº ³" &³ ßW {j * 0.1 m/sf 0.5 m/s F;~&b, Ò~7 f 10 kgf" 30 kgf~ v j F~& . Z²7~ ãÖ j÷Ë~& Nï~ ãö ¦O>Ú ®bæ Nï ~ 7æ7öB ç ãö ®j &ËW ¸ . V¢B Þ¿: ~ ^OË 7æ7 êO Ê*9 ÿ» t. g. 8. o. Fig. 6. A photo of tracked vehicle model waiting start of drawbar-pull.. o.

(7) Experimental Study about Tractive Performance of Tracked Vehicle on Deep-sea Sediment. 337. Table 2. Design of experiment (DOE) and results : L8 orthogonal array and verification test. 1 Grouser span mm 38 38 38 38 114 114 114 114. No.. 1 2 3 4 5 6 7 8 Verification test. 114. 2 chevron angle o. +15 +15 −15 −15 +15 +15 −15 −15 +15. Experimental variables 3 4 Draw-bar Speed pull m/s kgf 0.1 10 0.1 30 0.5 10 0.5 30 0.5 10 0.5 30 0.1 10 0.1 30 0.1. Performance values 5 Center of gravity mm 330 430 330 430 430 330 430 330. 30. 6 Driving Torque % Nm 4.82 3.56 5.45 4.51 3.98 10.82 2.11 10.56 0.16 6.49 5.54 11.05 2.98 3.63 6.62 4.88 4.74 4.09 *5.05(6.6%) 3.92(4.1%). Weight. Slip. kgf 157 178 178 157 157 178 178 157. 430. 178. *The effect of chevron angle on slip is neglected and is regarded as an error, because the effect is relatively small.. öB¦V 330 mm *~f © 100 mm ã 430 mm *~¢ æ> ~& . Nï~ Z²º ï 7æ{ 5.75 kPa" 6.5 kPaö >º 157 kgff 178 kgf ; ~& . çL8R þê³»ö ~ þÖ~ ª+8». þ Ö"º ïªC(ANOM, ANalysis Of Means)ö ~ >¯B (Park and Kang 2003). çvV~ ßW b¦V, WË~ö & þæ> >&~ Î"º j¾~ .öB þæ>~ >& B WË~. ~ ïj b áÚ ê . .¢ Ú, Òãö & Z²7 *~~ Ñ ® >& 330 mm(m )f v ® >& 430 mm(m )~ Î"º r~ (2) 5 (3)" ? áÚê . E1. E2. 1 m E 1 = --- ( η 1 + η 3 + η 6 + η 8 ) = 5.24 mm 4. (2). 1 m E 2 = --- ( η 2 + η 4 + η 5 + η 7 ) = 2.68 mm 4. (3). Fig. 7. Response of slip with respect to experiment variables: A, B, C, D, E and F denotes grouser span, grouser angle, track speed, drawbar-pull force, center of gravity, weight, respectively.. 1 8 m = --- ∑ η i = 3.96 8i = 1. (4). r~ (5)" ?f &»W(additive property)j ò ~º &»Î;(additive model) Wã º &;~ö ß ; Jêæ>~ ~ WË~& áÚê .. VB η º i® þ~ Òã . Ö"º Fig. 7ö E®ö ' >&ö & Î"¢ Ö Fb ¾æÚ Z²7 *~& Òãö ~º Î" η (=A m, B+, aC +, Db ,+Ec, F+ d) + e + f + ε (5) ¢ 2k > ® . ¯, þæ>~ >&ö ~ Î"¢ B jvbB WË~ö & Jêæ>~ ç&' VB a , b , c , d , e , f f Jêæ> A, B, C, D, E, F 'Ëê¢ 2k > ®b, WËBF~ OËj dj > ~ ïöB¦V~ j, k, l, m, n, o® >&8j ¾æÚ, ® . ε º i® WË~~ þJNf &»Î;~ JN¢ ~ Þ, Òã~ ï(m)f r~ (4)f ? áÚê . . i. i. j. k. l. m. j. j. i. k. k. l. m. n. o. l. n. m. o. n. o. i.

(8) Choi, J.-S. et al.. 338. (5)f ?f ' WË~~ &»Wj ò r *Ï .Z 9b, ¢Ö& Î"& Ò¢öb Òã f Ã& ©b .çB . Þ ¢Ö& *Ï .Z ~ Wã . §b, j** *ç(total shearing) æ" 7/~º η (A , B , C , D , E , F ) Þ¿~ ~ * *B B > ®V r^ö æ>b = m+a +b +c +d +e +f (6) ¦V Aº & 6²b Òãf Ã&~² F ©. . ¢Ö&~ ãª'~ ãÖ, "¯WËö ~ 'Ë η (A , B , C , D , E , F ) ìº ©b {>î . = m + (m – m ) + ( m – m ) + ( m – m) + ( m – m ) Ò~7" Nï~ Z²& "¯Nï~ WËj &~Ê (7) + ( m – m) + ( m – m) º º²¢º © {>î . $ £æ>Ï ZÊê VB η º ¦Ã þö & WË~~ º;8j ¾æÞ ; Nïj Jê r Z²7j ãb çê"¯WË. . *~ (6)" (7)j Ï~ ª~~ Jêæ> j ËçÎ º ©j { > ®î . öf Z² 7 '7ö ®b "¯ ZÊêNïf ç ö ~º WË~¢ áj > ® . ê¯OËö & êOb VÞÚê ; ê¯~² B ¦Ã þ. . VÞÚöf Êê~ 7æ 'j 6²Ê æ >~ {&&j Ã&Ê² Nb Nï "¯ö jº L çvV¢ Ï þ~ FÎW" Ò*Wj { ~V * ¦Ã þj >¯~& . ¦Ã þb êG ºêKf 6²~¾ ÿÎV~ ¦~º Ã&Êº Ö WË~f V~ L þb¦V .ç º;~ *~ "¢ &^Zb, Nï~ Òãf Ã&~² B . V¢B jv ¦Ãf B~ Table 2ö ¾æÚî . Þ, Òãö Z²7j ãb ÿÊ êOb VÞÚæº Ú & º;~~ ãÖ ãª'~ Î"& ç&'b 'ÚB ÿj ïj >ïçö &² Úÿ >& ®Ú WËj ËçÒ > ® . JNb ¦ç(Pooling)~ Òãj º;~& . Òã~ ãÖ êG WË~f º;~~ N& 6.6% >7 ZÊê Nïö &B, "¯³ê& FÚ , ÿÆJ~ ãÖ 4.1%î . æ>~ jOW" ' Kö ~ ê¯OËb ~7j A² B ®¢W, '« êGËj~ êGJN, Ò £ v^· . Kö ~ ~7f þöBº Ò~7b Ïö ~ &»Î JN¢ J êG WË~f º &Ú>î . V¢B FÚ'b &j ²z ;~~ N& 'f ©b 'B . V¢B L çvV > ®º Nï~ ;ç >7 "¯ö FÒ~ º © " ö V>j z þê³»ö ~ þ~ ªCÖ"& 6 ¯³êf Ò~7 Òã" ÿ&ö ~º Î"¢ OW £æ>j "¯~º ZÊêNï~ þÒö Û { > ®î . Ö"¢ B~º ©b 6>î . v. 2. 1. 1. 2. v. 2. 1. 2. 1. 1. 1. 2. 1. 2. 1. A2. E1. 2. 1. 2. 2. B1. C1. D2. F2. v. 8. 8. 8. 4. Ö # Æ~. ö L çvV¢ 'Ï þê³»ö ~ Ò WË þ~ Ö"& >Ú ® . Fig. 7f Òãö & þæ> ~ Î"¢ (2)¾ (3)" ÿ¢ O» b © . Fig. 7öB Òãj *V * B Jêæ>f ÚÏæ> F; rj Fv¢ . · ¢Ö& *Ï~ ãÖº 38 mm 114 mm& Òã j *¢ > ®º Jêª. · ¢Ö& ãª'~ ãÖº ç&'b Òãö & ' ËK 'r. · ÿ³ê~ ãÖº 0.1 m/s 0.5 m/s& FÒ. · ÒK~ ãÖº 30 kg 10 kg FÒ. · Z²7~ ãÖº 7æ7 ã FÒ. · Z²~ ãÖº 178 kg 157 kg FÒ. þj Û Òãj ²z~º ¢Ö&~ ' * Ï Ò º ©j .G > ®î . ò£ ¢Ö& Table 2. 8. 5. Ö. V. çvVR þê³»ö 8 8&æ ~ þj Û~ 6OW £æ>Ï ZÊê Nï~ Òãj &ç bR ~º "¯WË $j * ÎN' & >¯F > ®î . þ Ö" ªCö ~ £æ>Ï ZÊ êNï~ JêOËö & 8' ;& {>î . Nï~ ÒãBj R²z~8 * "¯Nï~ JêO Ëf r" ? ;Ò>î . · ¢Ö&~ *Ïö & ¸~ j(*Ï/¸)º 3.0 "¾R $B . · ¢Ö&~ ãª' çê"¯ Òãö ~º 'Ë f ~& . Ò~7bR R*F > ®º ¦"¯&j &/' · *¢ . · Z²7j 7æ~ 7 *Oö *~Êº © ± . · Nï Z²~ ã6 :²ç~ . L8.

(9) Experimental Study about Tractive Performance of Tracked Vehicle on Deep-sea Sediment. Ò. Ò. ¢^f ·>Öß; "B ‘& ÷7Ê 5 j7ÚÏVF BB’ "Bf V "B ‘· BB JêúæîÚç VF êz’~ ¢¦ªbR >¯> îÛî . ^^ò Chi, S.B., H.S. Jung, H.S. Kim, and J.W. Moon. 1999. Comparison of vane-shear strength measured by different methods in deep-sea sediments from KODOS area, NE Equatorial Pacific, ‘The Sea’ J. Kor. Soc. Oceanogr., 4(4), 390-39. (In Korean) Choi, J.S., S. Hong, and H.W. Kim. 2002. Experimental technique for trafficability on soft benthic terrain (I): Soil bin, p. 224-228. In: Proceedings of Annual Autumn Conference. Jinhae, Korea, October 25-26, Korea Commitee for Ocean Resources and Engineering. (In Korean) Dörfler, G. 1992a. Drawbar pull of a tracked vehicle on deep sea soil. p. 102-110. In: Proceedings of 4th Regional North American Meeting. Sacramento, USA, March 2527, International Society for Terrain Vehicle Systems. Dörfler, G. 1992b. Fahrwerksentwicklung für weiche Meereböden. p. 46-50. In: Conference on R&D for the machine construction. Karlsruhe University. Germany. (In German) Dugoff, H. and I.R. Ehrlich. 1966. Model tests in sub-. 339. merged soils. J. Terramechanics, 3(4), 53-70. Fukagawa, R., T. Tamai, T. Kobayashi, and S. Matsuno. 1998. Basic experiments on adhesion between clay and solid surfaces. p. 73-82. In: Proceedings of 5th AsiaPacific Regional Conference. Seoul, Korea, Oct. 20-22. International Society for Terrain Vehicle Systems. Hong, S. and J.S. Choi. 2001. Experimental study on grouser shape effects on trafficability of extremely soft seabed. p. 115-121. In: Proceedings of the 4th Ocean Mining Symposium. Szczecin, Poland, International Society of Offshore and Polar Engineers. Muro, T. 1983. Trafficability of tracked vehicle on super weak ground. Memoirs of the Faculty of Engineering, Ehime Univ., 10(2), 329-338. (In Japanese) Muro, T. 1988. Grouser effect on tractive performance of a bulldozer running on a superweak marine sediment. p. 355-366. In: Proceedings of 2nd Asia-Pacific Conference. Bangkok, Thailand, Dec. 6-10. International Society for Terrain Vehicle Systems. Nuttal, C.J. 1971. Traction limit for tracked vehicles crawling the sea bottom. J. Eng. Ind., Transactions of ASME, May 1971, 717-730. Park, K.J. and B.S. Kang. 2003. Theory of Machine Design, 198-200 p. (will be published, In Korean). Received Apr. 26, 2004 Accepted Jun. 8, 2004.

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