Engistics Pty Ltd
AustralianForestryContractorsAssociation
TasmanianLoggingTiltTest
Author: JonathanVilaBEngReviewed: SeanCarlsonBEngCPEngRPEQDate: 11/12/2018Issue: Issue2FileNumber:E1073
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ExecutiveSummaryThetestingoflogfrictionandvariousloadrestraintsystemsinTasmaniashowedhighvaluesoffrictionforeachofthelogspeciestested,relativetootherfrictiontestperformedonvariouslogtypesinotherregions.AlogthatspearedduringtransitindicatesthatlowerfrictionnativePeelerlogsmayexist.Allbartworestrainedtestsmetthe0.8grequirements.Amanualwinchwebbingincombinationwithabellychainachievedthehighesttiltangleof55°(at1.14G),easilysurpassingthe0.8grequirements.However,itprovedtobeinconsistentinbothitsappliedtension.Dyneemaachievedthehighesttensionandwiththeuseofairwinchesachievedthemostconsistency.Thebellychaincommonlyusedintheindustryalsoworkedverywell.Thiswasespeciallytrueincombinationwithwebbingstraps.Finally,Gripplateswereseentobeveryeffectiveatholdingthebottomlayerofthelogs.
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AFCAloggingtilttest(TASonly)
Dateoftest:26-27/07/18,OranaEnterprisesPtyLtd,LeganaPark,Tasmania
EngisticsEngineersPresent:SeanCarlsonJonathanVila
Acknowledgements:Engisticswishestothankthefollowingorganisationwiththistesting:OranaEnterprisesPtyLtdForicoPtyLtdSustainableTimberTasmania(STT)ANCForestryForestCentre(Aust)PtyLtdAustralianForestryContractorsAssociation
TestGoals:Thepurposeofthetestingwasto:
1. DeterminethestaticfrictionoffourtypesofTasmaniantimber:E.NitensPulpwood,Nativepulp,NativePeelerandE.NitensPeeler.Theseweredividedintotwoseparatetestlengths:thefirstat6mandthesecondat12m.
2. Assessthedifferenceinfrictionbetween6mand12mloglengths.
3. Assessthechangeinlogbehaviourbetweenrestrainedandunrestrained.
4. EvaluateDyneemaasarestraintsystem.
5. FurtherevaluateBellyChainsintesting.
6. FurtherevaluateWebbingstrapsasarestraintsystem.
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TestMethodology:Thetestmethodattemptedtosimulatetheloadingoflogsontoaloggingtrailerbyhavingtwobolstersrestrainedtoa40ftflatrack.Thetestbedwasthentiltedfromoneenduntilthelogsmovedoruntilasatisfactoryanglereplicating0.8gwasreachedtosatisfyEN12195.Overtwentyseparatetestswereconductedaslistedinthetablebelow.Duringthesetests,thetypeoftimber,itslengthandtheangleoftheflatrackwererecorded.Alltestliftswererecordedviavideotocapturethemomentofmovement.
Figure1:6mPeelersonflatrack
Aheadboardwasfixedtotheforwardbolsterframetobothreducetheamountoflogmovementandreducecleanuptimeiflogsweretomoveoutofthebolsters.
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Figure2:6mlogstestsetup
Thetesthowever,didhavecertainlimitationssuchas:
• Reducedanglerangeduetothescaleofthetestandcraneconstraints• Craneconcernsoverstabilityoftestrig• Headboardsafety,thebaymasswasreducedtoensuretheheadboard
couldadequatelyblocktheload• Deformationoftheflatrackanchorpointsduetheliftingchainapplying
highlyconcentratedloads• Concernsofoverturning
AllconcernsweredocumentedintheRiskAssessmentpriorandduringthetesting.
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Equipment:Thetestsinvolvedavarietyofequipmentbothtomeasureandrestrainthelogs.Suchequipmentincluded:
• ElphinstoneEngineeringfabricatedLogbolsterswithroundpegsandgripbarstoreplicatethetransportoflogsontrailers
• 75mmWebbingstraps;• Elphinstonemanualloadbinders• BellyChaintensionedbyamaxibindermanualtensioner• 5m10tonWLLDyneemaropeswereusedfortherestrainedtests• 1x3ttensionLoadcell,1x5ttensionLoadcellformeasuringtensionin
thetiedownsystem.• Airwincheswithanapproximateairsupplypressureof100psi.• 2xExTeTU16winchesconfigured1:1forWebbingorDyneemaas
required• Variouscamerasandtestequipmenttomeasureangleandmovementof
logs• 40ftflatrack• 85tonboomcrane
Figure3:AirWinchsetup(withTensionLoadcell)vsManualwinchsetup
Figure4:AirWinchwithDyneemapostlogmovement
Tension Load cell
Dyneema/webbing strap
8mm Chain on air
Staunchion
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Results:
Test Size(m) Type Angle Friction Effective
G-ForceRestraintmethod Comments
1 6 E.NitensPulp(Forico) 42 0.90 0.9 1 Toptierlogsmovement
2 6 E.NitensPulp(Forico) 43 0.93 0.93 1 Fulllogmovement
3 6 E.NitensPeeler(Forico)
- NA NA 1 FulllogmovementWet,Equipmentfailure
4 6 E.NitensPeeler(Forico)
40 0.84 0.84 1 Wet,angleadjusted,toptiermovement
5 6 E.NitensPeeler(Forico)
47 0.84* 0.74^ 4 Toptiermovement,wetandangleadjusted
6 6 E.NitensPeeler(Forico) 40 0.84* 0.71^ 2 Toptiermovement
7 6 E.NitensPeeler(Forico) 55 0.84* 1.14^ 3 Nomovement
8 6E.NitensPeeler
(Forico) 53 1.33 0.84 8 Nomovement
9 6 NativePeeler(STT) 40 0.84 0.84 1 Fullmovement,BlockingWebbingstrapfailure
10 6 NativePeeler(STT) 37 0.75 0.75 1 Fullmovement
11 6 NativePeeler(STT) 47 0.8* 0.85^ 4 Dyneematest
12 6 NativePeeler(STT) 49 0.8* 0.94^ 5 Dyneemawithbellystrap(chain)
13 12 NativePulp(STT) 42 0.90 0.9 1 Nomovement
14 12 NativePulp(STT) 41 0.87 0.87 1 Nomovement
15 12 NativePulp(STT) 50 0.88* 1.04^ 4 Nomovement
16 12 NativePulp(STT) 50 0.88* 1.04^ 6 Nomovement
17 12 E.NitensPulp(Forico) 37 0.75 0.75 1 Fullmovement
18 12 E.NitensPulp(Forico) 37 0.75 0.75 1 Fullmovement
19 12 E.NitensPulp(Forico) 52 0.75* 1.09^ 7 NoMovement
20 12 E.NitensPulp(Forico) 50 0.75* 1.00^ 5 Toptiermovement
21 12 E.NitensPulp(Forico) 49 0.75* 1.03^ 4 Fullmovement
22 12 E.NitensPulp(Forico) 46 0.75* 0.96^ 2 Fullmovement
Table1:Initialresults
*Assumedfromunrestrainedtest^Calculated
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Restraintmethod
1 Unrestrained
2 2x75mmWebbingonExTeWinch
3 2x75mmWebbingstrapsonExteWinch,BellyChain
4 2xDyneemaonExTeTU16
5 2xDyneemaonExTeTU16,BellyChain
62x75mmWebbingstraps,
ElphinstoneManualwinch,bellychain
7 2xWebbingstraps,Elphinstonemanualwinch
8 BellyChainonly
Table2:RestraintMethod
Day1oftestinginvolvedonly6mlogsandday2,only12mlogs.Thisallowedminimumdelaysforsettingupthetestrig.Ingeneral,alltypesoftimberweretestedbothunrestrainedandrestrained.Inthecaseoftherestrainedtests,amixofwebbingstrapsandDyneemawereusedforrestraintsaswellaschainbellystrapstounitisethelogs.Itmustbenotedthatinsomecases,tiltingofthetestrigwaslimitedduetosafetyconcernsrelatingtocranestability.Thislimitedboththetiltangleaswellasthetotallogsputonthetestrigitself.Test3wasdisregardedduetoamalfunctionoftheanglemeasurementequipmentduringtesting.Itwasfixedforthefollowingtests.E.NitensPulpwastestedinprevioustestingat6mandwasthusonlybrieflytestedatthislength.Itfeaturedmoreheavilyontheseconddaywith12mlogtesting.E.NitensPeelerandNativePeelerswereonlytestedduringthefirstdayat6mlengths.NativePulpwasonlytestedontheseconddayat12mlengths.Theresultsshowextremelyhighanglesoftiltbeforemovementandinsomecases,nomovementatall.
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Analysisofresults:
FrictionofTasmanianlogs:Thefrictionofthelogswasevaluatedusingrestrainedandunrestrainedtests.AnunrestrainedtestevaluatesthefrictionusingasimpleprocessoftakingtheTangentoftheangletodeterminefriction.Therestrainedtestincludestheeffectoftiedownforceintheformulafordeterminingfriction.Inbothcases,ahigherangleoftiltequatestoahighercoefficientoffriction.Thestaticfrictionforunrestrainedtilttestsiscalculatedusingtheformula:
µ=Tan𝜃
Thestaticfrictionforrestrainttilttestsiscalculatedusingtheformula:
𝑚𝑔× sin𝜃 = 𝜇 ×((𝑚𝑔× cos𝜃)+ 𝐹! )
𝑤ℎ𝑒𝑟𝑒: 𝐹! = 𝐶𝑙𝑎𝑚𝑝𝑖𝑛𝑔 𝑓𝑟𝑜𝑚 𝑙𝑎𝑠ℎ𝑖𝑛𝑔: 𝑇 × 𝑠𝑖𝑛𝐸 × 𝑔
𝜇 = 𝑓𝑟𝑖𝑐𝑡𝑖𝑜𝑛 𝑜𝑓 𝑙𝑜𝑔𝑠
𝑇 = 𝑡𝑒𝑛𝑖𝑠𝑜𝑛 𝑜𝑓 𝑙𝑎𝑠ℎ𝑖𝑛𝑔 𝑖𝑛 𝑘𝑔
𝑚 = 𝑚𝑎𝑠𝑠 𝑜𝑓 𝑙𝑜𝑔𝑠 𝑖𝑛 𝑘𝑔Hence:
𝜇 =𝑚𝑔× sin𝜃
((𝑚𝑔× cos𝜃)+ 𝐹! )
Belowisanexampleofanunrestrainedtest:Test1,UnrestrainedE.NitensPulpwoodwithamovementofthreelogs:
𝜃 = 42 𝑑𝑒𝑔𝑟𝑒𝑒𝑠
𝜇 = tan 42
𝜇 = 0.9
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Test Size(m) Type Angle Static
Friction
AverageStaticfriction
1 6 E.NitensPulp 42 0.900.92
2 6 E.NitensPulp 43 0.93
4 6 E.NitensPeeler 40 0.84 0.84
9 6 NativePeelers 40 0.840.80
10 6 NativePeelers 37 0.75
13 12 NativePulp 42 0.900.88
14 12 NativePulp 41 0.87
17 12 E.NitensPulp 37 0.750.75
18 12 E.NitensPulp 37 0.75Table3:Frictionvaluesoflogs(Unrestrained)
ThetilttestinginTasmaniashowedveryhighcoefficientsoffrictionacrosstheboard.Howeverprevioustestingofsimilartypelogs,specificallyintheGreenTriangleRegionidentifiedlowerfrictionvaluesforPulplogs(Globulus).OurcomparisonslookatNativePeelersversusMountainAshandE.NitensPeelerversusRB40(Pinesawlogs).Engisticsrecognisesthattherearedifferencesbetweenthesespeciesandishappytohaveclarificationtoimprovethecomparison.RestrainttestingusingeitherwebbingorDyneemashowedtheymettheperformancestandardsatthisfrictionattimeoftest.
Figure5:Logmovementintransit
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Anissuethatarose(relatingtothecurrentfrictionofthelogs)wasthatduringtransittothetestsite,oneoftheNativePeelerlogsspearedforwards.Inthiscase,thelogswererestrainedusingwebbingstrapstensionedwithabasiccommonhandoperatedwinch.Thedriveradvisedthatnoheavybrakingorimpacthadbeenexperiencedintransit.Thiswouldindicatethatdecelerationoccurredthroughmoderatebrakingwhichwouldtypicallyprovideforcesonthelogsofbetween0.55to0.6g.Inthiscase,eveniftheappliedloadrestrainthadaminimalimpactonthelog,andthemovementcamefromfrictionalone(bestcasescenarioforthehighestfriction),thestaticfrictionwouldbeintherangeof0.55-0.6.OurobservationisthatthelogthatmovedintransitiscomparableinfrictiontoMountainAsh.Engisticscanonlytheoriseonthisincreaseinfrictionbetweenintransitloadshiftandinrigresults;however,itcanpossiblybeattributedtoafewlikelycauses:
• Traveltimesbetweenloggingoperationsandtestsitecouldhaveallowedconvectiondryingtoimpactfriction;
• Differencesintestrackconfigurationcomparedtoonvehicleloadconfiguration.
• Seasonaleffects• Increasedlogmarksfromwinteroperations.• Timebetweenharvestingandtransport
CommentaryProvidedbyForicoindicatedthatduringwinter,additionalmarkingonthelogsoccurduetooperationalrequirementswhenremovingbranches.Thiswouldhavethepotentialtocontributetheincreasedfrictionofthelogsduringtesting.ThetimingofthelogsfortestinginrelationtothetimebetweenharvestingandtransportingisreflectiveofmostlogtransporttasksinTasmaniafromdiscussionswithoperatorsduringtesting.Duetothehighfrictionoflogsfound,thenextstepwastoreviewtheeffectivenessofloadrestraintsystems.Thisincludedusingacombinationofwebbingstraps,airwinches,manualwinchesandbellychains.Dyneemawasalsoextensivelyusedtodetermineitseffectivenessasapotentialalternativerestraintsystem.Theeffectivenessofarestraintsystemismeasuredbyitsappliedtensionandtensionloss.Thehighfrictionofthelogsassistedgreatlytotheperformanceoftherestraintsystem.
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SummaryofDyneematensions:Dyneemawasheavilyfeaturedintherestrainedteststoreviewitseffectiveness.Theresultsbelowshowthemeasuredtensionsonboththehighandlowsideswiththehighsidebeingthesideoftheairwinch.
Figure6:6mPeelers
Test Size(m)
Type Tension(High)kg
Tension(Low)kg
DifferenceHightoLow
(%)5 6 E.Nitens
Peeler510 402 79
11 6 NativePeeler
560 360 64
15 12 NativePulp 722 380 53
Airpressureapproximate100psibasedon50mmgaugefromtruckcompressor.
Table4:DyneematensiondifferencebetweenLowandHigh
ThetensionintheDyneemawasnotconsistentbetweentestsbutregisteredhigherthanwebbingstraps.Tensioninthe12mlogsregisteredthegreatestdisparitybetweenHigh(left)endandlow(right)side.Previoustestingfoundthattheratiobetweenthelowsideandhighsidewasaround43%.Currenttestresultsarehigherthanthisvalue,suggestingthatthetestsetupwascorrect.However,ourDyneematensionvaluesdonotalignwithvaluesfoundduringprevioustesting(1000kg-1200kghighsidecomparedtocurrenttestresultsof500-700kghighside).Thissuggeststhatthetestairpressurewaslikelylessthanpreviouslyunderstoodwheremajorityofprevioustestswerearound115psi.Thisispotentiallyattributedtothegaugeresolutionnotpermittingaccuratepressuremeasurement.AnEngisticslearningfromthisprocessistoensurehigherresolutiongaugesareavailablewhenperformingsimilartests.
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BellyChain:TestingwascompletedwithvariousrestraintsystemsincludingcombinationsofDyneema,75mmWebbingstrapsandBellyChainscombined.Bellychainwastensionedwithamaxibindermanuallytensioned.Thetablebelowprovidesacomparisonoftestsforsystemswithandwithoutbellychainsapplied.
Test Size(m)
Type Angle(degrees)
G-Force Restraint Comments
6 6 E.NitensPeeler
40 0.71 2xWebbingstraps Toptiermovement
7 6 E.NitensPeeler
55 1.14 2xWebbingstraps,BellyChain
Nomovement
8 6 E.NitensPeeler
53 0.84 BellyChainonly NoMovement
11 6 NativePeeler
47 0.85 2xDyneema Dyneematest
12 6 NativePeeler
49 0.94 2xDyneema,BellyChain Dyneemawithbellystrap(chain)
19 12 E.NitensPulp
52 1.09 2xWebbingstraps,manualwinch,BellyChain
NoMovement
20 12 E.NitensPulp
50 1.00 2xDyneema,BellyChain Toptiermovement
21 12 E.NitensPulp
49 1.03 2xDyneema Fullmovement
Table5:BellyChaineffect
Theresultsoftest19areonlyincludedforcompleteness,asatestwasnotundertakenwithoutabellychainforcomparison.InthecasewhereDyneemawasused,asmallincreaseinrestraintcapacity(by1-2degrees)wasseenwhenaBellyChainwasapplied.However,therewasadramaticincreaseinrestraintcapacitywhenabellychainwasusedincombinationwithwebbingstraps(atotalof15degreesincreaseintest7comparetotest6).ThisisalsohighlightedbytheG-forceachieved:Intest6the0.71Greachedwouldhavemeantthattheloadwouldnothavesuccessfullyachievedtherequired0.8G.However,theadditionofaBellyChaingreatlyincreasedtheG-forceto1.14G.
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Figure7:6mSawlogtestingwithbellychain
ThisdiscrepancybetweenDyneemaandwebbingstrapsismostlikelyattributedtothedifferenceintensionbetweenthetwo.Inallcases,Dyneemaregisteredhighertensionvaluesthanwebbingstraps.ThiswouldmeanthatabellychainplayedagreaterroleintherestraintofthelogswithwebbingthanitdidwhenusedinconjunctionwithDyneema.Interestingly,test8showedthatabellychainonitsownachievedtherequired0.8G.Thisindicatesalogfrictionof1.33.Thisresultshowsthevalueofabellychainandisindicativeofthegainsachievedwithitsusage.Thefrictionvaluesobtainedintestingalsoassisttheperformanceoftheloadrestraintintesting.Thisisacommonfeatureofalltests.
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WebbingtensionLoss:Whilstwebbingstrapswereusedforseveraltests,wenoticedamarkeddecreaseintensionovertimeaswellaslowertensionvaluesoverall.Test Size
(m)Type HighTension
(kg)LowTension
(kg)DifferenceHightoLow(%)
6 6 E.NitensPeeler
340@approx1min
127@approx1min
37
7 6 E.NitensPeeler
400@approx1min
125@approx1min
31
16 12 NativePulp Elphinstonemanualwinch
522
400 76
19* 12 E.NitensPulp
Elphinstonemanualwinch
InitialTension:@approx1min
640 320 50
Tension@midtest: 540 320 59
Tension@endoftest(0degreestilt)
330 350 106
*Dataappearsinconsistent
Table6:WebbingtensiondifferenceLowtoHigh
From the table above, the tests that usedwebbing straps showed a significantdecreaseintensionvaluescomparedtoDyneemafortheExTeTU16winch.During test 19, the tension loss over time was recorded for an Elphinstonemanualwinch.ThetensiondropovertimewiththeElphinstonewinchwaslessthan with the ExTe TU16. This is thought to be related to the higher initialtension provided by the Elphinstone winch transferring more effectively overtheload.Whilst the initial tension was higher than the ExTe winch, the tension valuedropped significantly through the test process. This highlights the concernsrelatingtomaintainingtensionovertimeformanualtensioningsystems.A significant variation in tensions achieved by the manual Elphinstone winchwasidentifiedduringtesting.Thisisevidentinthedifferencebetweenthehighsidetensionsfortests16and19thathavea120kgdifference.Whilst the Elphinstone manual winch provides an initial total clampingcomparabletotheDyneemasysteminthistest,itisevidentthatthatthistensionisnoteasilymaintainedovertime,includingintransit.
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At theendof the testingday, a tension loadcellwasmountedon thewebbingstrap of a logging trailer. The purpose was to see the change in tension indynamicconditions.Theinitialtensioningofthestrapsshowedavalueof640Kgonwinch side.Within 15minutes, that value had dropped to 580kg onwinchside.Fromthere,thetruckandtrailerwasdrivenfor20minutesfor15km.Atthefirststop,theloadshowedavalueof397kg, i.ea lossintensionofover200kg.The loadwas re tensionedand thedrivena further15km.On the secondandfinalstop,thetensionremainedconstantat550kg.The testing showed that usingwebbing straps for restraintwas least efficientduetolargegapsbetweenlowandhighsidetension,aswellassignificantlossintensionovertimeinbothtestingandintransit.However,itisimportanttonotethatlossintensionispotentiallyduetothetestsetupwherealoadcellwasintroducedintotherestraintsystembymeansofasecondary system and choking. It is feasible that slippage occurred during thetestingorlogcompression,providedtensionlossesintheresults.ThetablebelowalsocomparesthedifferenceintensionbetweenDyneemaandwebbing.Tests5and6showthatduringSawlogtesting,Dyneema(test5)registeredhighertensionsthanwebbing(test6).Whilstintest19,thewebbingtensiondecreasedwhentestingbeganwhilstDyneemaremainedconstantintest20.
Test Size(m) Type Tension
(left)kgTension(right)kg
Restraintsystem Comments
5 6E.NitensPeeler 510 402
2xDyneemarope/ExTe16
winch
Toptiermovement,wet
andangleadjusted
6 6 E.NitensPeeler
340 127
2x75mmwebbing
strapswithExTe16Winch
Toptiermovement
19 12 E.NitensPulp
Initial:640Start:540@50:410End:330
Initial:320Start:320@50:410End:350
2x75mmWebbingstraps,
Elphinstonemanualwinch
NoMovement
20 12 E.NitensPulp
650 650
2xDyneemarope,ExTe16winch,Belly
Chain
Toptiermovement
Table7:DyneemavsWebbingtension
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12mvs6mlengths:The table below shows a comparison between E.Nitens Pulp 6m and E.NitensPulp12m,andE.NitensPeeler6mandNativePulp12mlogs.WhilstthereisanorganicdifferencebetweenNativepulpandE.NitensPeeler,thecomparisonwasmade due to the quantity of logs used and their similarity in diameter. Thiscomparison only compares unrestrained results. Due to time and availabilityrestrictions,notestingwasconductedon12mPeelers.InthecaseofNitensPulp,therewasasignificantdifferencebetweenthe6and12m lengths,with higher friction found the 6m logs. Thiswas reversed in thesecond comparison, with the 12m Native logs having a higher friction value(althoughnotasignificantincrease).Duetotheseresults,itisrecommendedthatthelowestfrictionvalueregardlessofloglengthbeconsideredduetoinconsistenciesoffrictionacrosslengths.Size(m) Type AverageFriction FrictionDataPoints
6 E.NitensPulp 0.92 0.900.93
12 E.NitensPulp 0.750.750.75
6 E.NitensPeeler 0.84 0.84
12 NativePulp 0.88 0.900.87
Table8:Loglengthcomparison
Lashinganglesoncentrallogs:Theanglesonthelashingsappliedtothecentrallogsinthepilewereverylowtonil.Thismeantverylittletiedownforcewasappliedtotheselogsandwasthemainreasonwhymanyofthetestssawspearingofthetoplayer.Thisitselfhighlightsoneofthemainissueswiththecurrentrestraintsystem:itseffectivenessisstronglydependentontheshapeofthelogpileinthebolsters.Acrowningeffectwouldallowincreaseddownwardsforcetobeappliedtothecentrallogsandprovideanoverallbetterrestraintsystem.However,achievingthiscrowningisdifficultandofteninconsistent.
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Figure8:Angleoncentrallogs
Potentialsolutionsinclude:
• Blockingorcontainmentmethodsofrestraint.• Anothersolutioncouldbetheestablishmentofacleardiagrammatic
standardonwhatgoodcrowninglookslikeforeachlogtype.• Finallybyhavingcamerasincludedincertainareasofforwardersor
loaderswouldallowoperatorstobettervisualisetheloadonthetruck.
Gripplateeffect:Agripplatewasusedinalltests.Theresultsshowthatthegripplateensuredthatthecriticalfrictionwasbetweenlogonlog,insteadoflogonsteel,whichhasalowerfriction.Theimagebelowofthedeformedplateshowsthattheplatedugintothelogsensuringimprovedfriction.Duetotheireffectivenessintesting,itisrecommendedthatgripplatesbeusedonhorizontalbedstoimproveloadrestraint.
Figure9:GriporCrocodileplate
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ConclusionOverall,thetestingshowedaveryhighstaticcoefficientoffrictionacrossalllogtypes.ApplyingarestraintsystemincreasedthecapacityofthelogstowithstandhigherG-forces.Thishadtheeffectofmakingitdifficulttounderstandthedifferencesbetweenlengthvariationsandrestraintsystems.Sincethetestingshowedsuchhighfrictionvalues,allrestraintmethodsweredeemedadequate:Webbingachievedthe0.8GrequirementsinallcasesexceptwhentestingE.NitensPeelers.ThisalsooccurredwhenDyneemaforthisparticulartest.Theadditionofabellychainimprovedallsystemstoachievethe0.8Grequirements.Duetothehighmeasuredfrictionofthelogs,eachloadrestraintmethodwasreviewedforitsefficiencyinbothitsappliedtensionandtensionlossovertime.Itisimportanttonotethatalackofcrowningofthelogsoftencausedthetoptierlogstomove.Logswereloadedandcrownedconsistentwithhowtypicalloadswouldbecompletedatalanding.
GoalOutcomes:Inlinewiththetestgoals,thefollowingoutcomeswereachieved:
1. ThestaticfrictionoffourtypesofTasmaniantimber:o Staticfrictionofallfourlogtypeswasfoundtobeveryhighas
seenbelow.Thisisinconflictwithprevioustestingwhichshowedlowervaluesforsimilarlogtypes.Thecauseofthiswasattributedtopotentialseasonalconditionsandconvectiondryingduringtransport.
Test Size(m) Type Angle Friction
1 6 E.NitensPulp 42 0.90
17 12 E.NitensPulp 37 0.75
4 6 E.NitensPeelers 40 0.84
9 6 NativePeeler 40 0.84
14 12 NativePulp 41 0.87Table9:Logtypefrictionvalues
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2. Thedifferenceinfrictionbetween6mvs12mbeamlengths:o Thedifferencesbetween6mor12mloglengthsinthetablebelow
showedthatusingthelowestfrictionvalue,regardlessofloglength,wasthemosteffectiveoptionduetotheinconsistenciesinfrictionwithdifferentlengths.Bytakingthelowestvalue,asystemofrestraintcanbedevelopedusingthelowestcommondenominatorandaccountforalllogtypes.
Size(m) Type AverageFriction
FrictionDataPoints
6 E.NitensPulp 0.92 0.900.93
12 E.NitensPulp 0.750.75
0.75
6 E.NitensPeeler 0.84 0.84
12 NativePulp 0.88 0.900.87
Table10:Estimatedfrictionvaluesbetween6mand12mloglengths
3. Changeinlogfrictionbehaviourbetweenlashedandunlashed:
o Lowcrowninganglesmeantthatspearingofthetopmiddlelogsaccountedformostlogmovements.Belowhighlightsthemainareasforlogmovementduringtesting.
o Thetestingshowednodiscerniblechangestofrictionvalueswhenlogswerelashedcomparedtowhentheywereunlashed.
4. EvaluateDyneemaasarestraintsystem:
o AcombinationofairwinchesandDyneemaprovedtobethemosteffectiverestraintsystematmaintainingconsistenthightensionsthroughouttesting.
o Dyneemaappearstobeasuitablelashingsystemfortherestraintoflogs.However,thisissubjecttoevaluationoflong-termwearandensuring110psiisachievedonairdelivery.
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5. FurtherevaluateBellyChainsintesting:o Theuseofabellychain,whilsteffectiveinbothrestraintsystems,
provedtoonlybeamajorinfluencewhenincombinationwithwebbingstraps.ThiscanbeattributedtomoreconsistenttensionvaluesfromtheDyneemaasopposedtothewebbingstraps andthelowerperformanceofthewebbingsystems.However,Bellychaintensionedwithanon-recoilingbinder(I.enoovercenterloadbinders)isrecommendedfortherestraintofNativeandNitenslogs.
Test Size
(m)Type Angle
(degrees)Restraint Comments
6 6 E.NitensPeeler
40 2xWebbingstraps Toptiermovement
7 6 E.NitensPeeler
55 2xWebbingstraps,BellyChain
Nomovement
11 6 NativePeeler
47 2xDyneema Dyneematest
12 6 NativePeeler
49 2xDyneema,BellyChain
Dyneemawithbellystrap(chain)
19 12 E.NitensPulp
52 2xWebbingstraps,manualwinch
NoMovement
20 12 E.NitensPulp
50 2xDyneema,BellyChain
Toptiermovement
21 12 E.NitensPulp
49 2xDyneema Fullmovement
Table11:BellyChaineffect
6. FurtherevaluateWebbingstrapsasarestraintsystem:
o TheuseofwebbingstrapswithanairandmanualwinchshowedlowertensionsinthelashingsthanwhenusingDyneema.
o Webbingstrapssufferedthemostlossintensionovertimeinbothtestingandintransit.
Othertestoutcomes:
o Airwinchesweremoreeffectivethanmanualwinchesastheywereabletomaintaintensionthroughouteachtest
o WinchtensionfromtheExteTUwasnotedtobealmosthalfthatofprevioustesting,whichwouldhaveasignificanteffectontheresults.Thisisthoughttobeduetolowairpressuredeliverytothewinch.Ahigh-resolutiongaugeshouldbeusedtoensure110psipressureisachieved.
o Gripplatesensuredfrictionoutcomeswerebetweenlogonlogandnotlogonsteel.Gripplatesprovedtobeeffective.