Addressing circular economy through design for X approaches: A systematic literature review

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ContentslistsavailableatScienceDirect

Computers

in

Industry

j o ur na l h o me pa g e :w w w . e l s e v i e r . c o m / l o c a t e / c o m p i n d

Addressing

circular

economy

through

design

for

X

approaches:

A

systematic

literature

review

Claudio

Sassanelli

a,∗

_,

_Andrea

_Urbinati

a,b

_,

_Paolo

_Rosa

a

_,

_Davide

_Chiaroni

a

_,

_Sergio

_Terzi

a a_Department_of_Management,_Economics_and_Industrial_Engineering,_Politecnico_di_Milano,_Piazza_Leonardo_da_Vinci_32,₂₀₁₃₃_Milan,_Italy b_School_of_Industrial_Engineering,_LIUC_Università_Cattaneo,_Corso_G._Matteotti,_22,_21053,_Castellanza,_Varese,_Italy

a

r

t

i

c

l

e

i

n

f

o

Articlehistory:

Received16December2019

Receivedinrevisedform10February2020 Accepted15April2020 Keywords: Circulardesign DesignforX Circulareconomy End-of-Life Sustainability Product-ServiceSystem Designguidelines Knowledgemanagement Productdesignapproach Environmentalproductdesign Designforsustainability Designforenvironment Remanufacturing Recycling Recover Reuse Reliability

Circulardesigndecision-support Circulardesignmetricsandevaluation Systematicliteraturereview

a

b

s

t

r

a

c

t

Guidedbyatechnologicalrevolution,widelydiscussedparadigmsasservitizationandCircularEconomy

(CE)areprogressivelypushingmanufacturerstowardsdeliveringincreasinglycomplexsolutions.Design

playsastrategicroleinthissense,eitherconsideringproducts,servicesorProduct-ServiceSystems(PSSs).

Concurrentengineeringand,speciﬁcally,DesignforX(DfX)approacheshavebeenwidelyassociated

toproducts,revealinggreatpotentialitiesforenhancingservicefunctionalitieslikesupportabilityand

circularity.Again,DfXapproacheshavebeenalreadyexploitedtosystematicallysupportthePSSdesign

process,giventheirre-knownabilitytoallowabetterinformationsharingbetweenproductdesigners

andservicemanagers.However,evenifseveralDfXapproachesrelatedwiththeEndofLife(EoL)stage

alreadyexist(e.g.Designforrecycling,remanufacturingandEoL),theystillneedtobetterﬁtwitha

circulardesignperspective.Therefore,theaimofthispaperisexploringandunderstandinghowdesign

cancontributetowardsaCEtransitionthroughtheadoptionofDfXapproaches.

license(http://creativecommons.org/licenses/by-nc-nd/4.0/).

Contents

1. Introduction...2

2. Materialsandmethods...2

3. Literaturereview...3

Abbreviations:AM,AdditiveManufacturing;BM,BusinessModel;CBM,CircularBusinessModel;CLPSS,CircularLifecycleofPSS;CE,CircularEconomy;DfA,Designfor Assembly;DfAd,DesignforAdaptability;BoP,BaseofthePyramid;DfCom,DesignforCompatibility;DfD,DesignforDisassembly;DfD&Rea,DesignforDisassemblyand Reassembly;DfE,DesignforEnvironment;DfEoL,DesignforEndofLife;DfMA,DesignforManufacturingandAssembly;DfM,DesignforMaintenance;DfMo,Designfor Modularity;DfLLUoP,DesignforLongLifeUseofProducts;DfX,DesignofX;DfPSSu,DesignforProductServiceSupportability;DfRecy,DesignforRecycling;DfReco,Design forRecovery;DfRel,DesignforReliability;DfRem,DesignforRemanufacturing;DfRema,DesignforRemake;DfSa,DesignforSafety;DfSC,DesignforSupplyChain;DfSR, DesignforSocialResponsibility;DfSt,DesignforStandardization;DfSu,DesignforSustainability;DfUpg,DesignforUpgradability;EEE,ElectricalandElectronicEquipment; ELV,EndofLifeVehicle;EoL,EndofLife;ICT,InformationandCommunicationTechnology;IS,InformationSystem;KET,KeyEnablingTechnology;MLC,MultipleLifeCycle; PSS,Product-ServiceSystem;SC,SupplyChain;SLC,SlowingLifeCycle;SLIP,Sort-Label-Integrate-Prioritize;SME,SmallandMediumEnterprise;SysC,SystemChange.

∗ Correspondingauthor.

E-mailaddress:[email protected](C.Sassanelli). https://doi.org/10.1016/j.compind.2020.103245

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2 C.Sassanelli,A.Urbinati,P.Rosaetal./ComputersinIndustry120(2020)103245

3.1. ExtantstateoftheartonDfXapproachessupportingtheadoptionofCircularEconomy...4

3.1.1. Circulardesignimprovement ... 6

3.1.2. Circulardesignmetricsandevaluation ... 9

3.1.3. Circulardesigndecision-support ... 13

3.1.4. Designdrivingcirculartransition...13

3.1.5. Circulardesignknowledgemanagement...13

4. Discussion...13

5. Conclusions...21

Acknowledgements ... 22

References...22

1. Introduction

Considering the highcompetition of current industrial con-texts,manufacturersareaskedtodeliverproductscharacterized byanincreasingcomplexity(Maeda,2006;Norman,2011;Velte andSteinhilper,2016).Productsaresupposedtoaddressnew cir-cularanddigitalfeaturestobeintegratedandsystematizedwith multipletraditionalfunctionalities,oftenthankstothe introduc-tionofnewtechnologies.Fromoneside,thesustainability(WCED, 1987)andCircularEconomy(CE)paradigms(TheEllenMacArthur Foundation,2015)raisedbothcustomers’andproviders’awareness aboutnatural resourcesscarcity.Fromanotherside,the serviti-zationparadigm(Vandermerweand Rada,1988)supportedthe adventofamoresustainableeconomy(Stahel,1997;Botsmanand Rogers,2010; Bocken et al.,2016), by changingthefocus from productstoproduct-relatedservices(Goedkoopetal.,1999).Like evidencedbyliterature,thesetwoparadigms canbeinfluenced andenabledbytechnology(PorterandHeppelmann,2015;Rosa etal., 2019a).In order topursuethis transition,manufacturers havebeencompelledinchangingtheirbusinessmodels(Bocken etal.,2014),bydetectingandavoidingrelatedhurdles(Brax,2005; Gebaueretal.,2005;deJesusPachecoetal.,2019)andexploring potentialbenefits(Rosaetal.,2019b).However,methodsandtools supportingthesystematicintegrationofproduct-servicesundera circularperspectivearestillunderdevelopment.Someinitial ben-efitsgoinginthisdirectionhavebeenreachedthroughconcurrent engineering(ClarkandFujimoto,1991;Clausing,1994). Specifi-cally,DesignforX(DfX)guidelines(GatenbyandFoo,1990;Huang, 1996) are interpreted as a concurrent design of products (and relatedprocesses/systems)pluscertainabilitiesincopingwitha specificrequirement(e.g.features,performance,constraints,etc.). EvenifDFXcanenhance competitivenessmeasures,rationalize product/process/resource design decisions and improve opera-tionalefficiencyinproductdevelopment(Huang,1996;Kuoetal., 2001), they arequite oldapproaches (Gatenby and Foo, 1990). Again,lookingattheEndofLife(EoL)stage,evenifseveralDfX methodsandtoolsalreadyexist,theystillneedforacircular per-spective(Bakkeretal.,2014).WithintheProduct-ServiceSystem (PSS)contextDfX havebeenrarelyconsideredbyexperts:they havebeenproposedasameantofillinthegapofknowledgeof designersaboutproductlifecyclestages,favouringabetter infor-mationsharingbetweenproductdesignersandservicemanagers (SassanelliandPezzotta,2019).Wrappingup,severalDfXresearch attemptsdealingwithCEhavealreadybeenconductedbut lack-ingofanoverallandsystematizedapproach.Therefore,theaimof thisworkistoexploreandunderstandhowdesigncancontribute towardsaCEtransitionthroughtheadoptionofDfXapproachesto deliversuitableproduct/service/PSS.Thepaperisorganizedas fol-lows.Section2explainstheadoptedresearchmethodology.Section 3presentsresultscomingfromtheliteraturereview.Section4 dis-cussesaboutresults.Finally,Section5providessomeconclusions andfutureresearchtrends.

2. Materialsandmethods

InordertobettersystematizetheDfX approaches contribut-ingtoa circulardesign,a systematicliteraturereviewhasbeen conducted.Theareaofinvestigationdidn’tfocusonthespecific contextofeitherproductorservicesorPSSs,lookingattheentire extantliteraturedealingwiththecirculardesignthroughthe adop-tionoftheDfXapproaches.Thekeywords“CircularEconomy”and itsmainsynonym“endoflife”(assuggestedbyarecentsystematic literaturereviewonCE(SassanelliandRosa,2019))werecombined witheither“DesignforX”,“DfX”or“designguideline”andsearched withoutanytime/documentrestriction.Resultsofthesequeries arereportedinTable1,confirmingthatthe“endoflife”context hasbeenexploredmorethanthe“circulareconomy”one.Atotal amountof402and339documentshavebeenfoundonScopus® andScience Direct®_,_{respectively.}_If_compared _to_the_more dis-cussedsingletopicsofCEandDfX,thesenumbershighlighthow thiscombinedresearchcontextisstillunder-investigatedevenif deservingmoreattentionfrombothresearchers’and practition-ers’side.Moreover,lookingatthesame searchesperformedon titles,abstractsandkeywords,resultsindicatethatthisresearch contextstillrepresentsaniche.Afterdiscardingredundancies,a finalsetof125documentswasconsideredforanalysis.These doc-umentshavebeenassessedintotwoways.Afirstanalysisoftitles, abstractsandkeywordsledtoa setof43 documents.Then,the readingoftheentiremanuscriptsconductedtoafinalamountof 31documents.Theselectionwasbasedontherelevanceof doc-uments,takingintoaccount onlythosecontributions proposing DfXapproachesandrelateddesignguidelinestofosterthe adop-tionoftheCEparadigmthroughthedeliveryofcircularsolutions. Specifically,authorsselectedonlythosedocumentscontributing toarealenhancementofDfXmethodsandpracticesunderaCE lens, enabling theirintegrationand systematization with tradi-tionalproductabilitiesthroughaconcurrentengineeringapproach. In particular,Fig.1 shows theresearchstrategy used inthe systematic literature review (Smart et al.,2017; Sassanelli and Rosa,2019): Table1 reports thefour stringsused tocarry out thesearchesonScopusand ScienceDirectdatabases,leadingto 741results.Furthermore,25documentswereconsideredthrough cross-referencingprocesses and4throughhandsearch.Last,15 moredocumentswererecommendedbyexpertstobeaddedtothe list.Applyingthecriteria,thesetofdocumentsfoundwasreduced attheendto31selectedarticlesthathadbeenfullyanalysed.The entireprocessofselectionandexaminationofthedocumentswas conductedbytwo authors,carrying itout autonomouslytonot fallinbiasofanalysisthroughoutthereview.Finally,theirresults werecomparedandmadeconsistenttoeachother,leadingtothe researchpresentedinthisarticle.

Asshowninnextsection,allthesepapershavebeencategorized bynationoftheﬁrstauthor,year,documenttype,researchtype (dividedinTheoreticalAssessment;AnalyticalAssessment;Case Studies; Surveys;Action Research;Other) and journal.

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Further-Table1

Searchesbykeywordsanddocumentsselection.

Searchbykeywords Scopus

® _Science_Direct®

Allﬁelds (Title-Abs-Key) Allﬁelds (Title-Abs-Key)

“Designguideline”AND“CircularEconomy” 33 (5) 10 (1)

“(DesignforX”OR“DfX”)AND“CircularEconomy” 45 (5) 59 (0)

“Designguideline”AND“endoflife” 157 (17) 40 (0)

(“DesignforX”OR“DfX”)AND“endoflife” 167 (15) 230 (0)

Total 402 339

Total(withoutredundanciesinthesameDB) 75 67 Total(withoutredundanciesbetweenthetwoDBs) 125

Total(aftertitle,abstractandkeywordsassessment) 43 Total(afterentiremanuscriptassessment) 31

Fig.1.Researchstrategy(adaptedby(Smartetal.(2017))).

Fig.2. Historicalpublicationtrendbyyear.

more,insub-section3.1thecontributionshavebeenanalysedand groupedbasedonthepurposeofusingDfXinthedesignprocess ofcircularsolutions,themainabilitiesrelatedtoDfXapproaches consideredtoaddressthesepurposesand thegapsdeclaredby researchersineachofthesecategories.

3. Literaturereview

Thetrendalong theyears oftheselected31 articles(Fig.2) showsaquitesteadyandweakinterestonDfXapproachesto fos-ter CEadoption,recording a growthfromaround 2015(61.3% ofthecontributionsarefrom2015onward).Thiscanbejustiﬁed by the blossom of several directives and regulations

indicat-ingonCE(EuropeanCommission,2014;EuropeanCommission, 2015) always more urgent to put right to global issues like resources depletion, consumerism and population growth (The EllenMacArthurFoundation,2015).

Concerningthetypeofcontributions(seeFig.3),17werearticles publishedin scientiﬁc journals,10 papers in international con-ferenceproceedingsand3weremaster/PhDthesis.Inlinewith resultscomingfromotherliteraturereviewsonCE(Sassanelliand Pezzotta,2019),JournalofCleanerProductionandResources, Conser-vationandRecyclingarethemostrecurrentjournals(with50%of thejournalarticlesconsidered).

Inviewofthenationalityofauthors,Europeancountries pro-videdthemajorityofcontributionsselected(71%),followedby North American countries (16,1%) and Southeast Asian/Chinese countries(12,9%)(Fig.4).

Assessingtheliterature,wecheckedthatmostofauthorsgave relevancetothetheoreticalside,inordertotrytodeﬁnea com-mongroundoftheories.19timesresearcherschosetoconducta theoreticalassessmentofthecontextwithoutbeingabletogive acomplete pictureoftheDfXneeded,mostlyduetothe multi-plicityandheterogeneityofthesekindofapproaches.Moreover, 6researchesconductedapplicationcases,mainlytovalidatethe methodsandtoolsproposedand6werecasestudytopractically explaintheproposedapproachesortodemonstratetheir useful-ness.Morethanhalfofthecontributions(19of31)providedonlya theoreticalviewontherelationshipbetweencircularityandDfX approaches:only12 documentsproposedapplicationcasesand

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Fig.3.Typeofcontributions:journalsarticles,conferenceproceedingsandthesis.

Fig.4. Publishingcountries.

casestudiestodemonstratethevalueoftheproposedresearches fromapracticalperspective.These12documentsproposedintotal 59cases:47caseswerecomingfrommasterandPhDtheses,10 fromactionresearchandcasestudiespapersand2from

theoret-icalanalyses(conductedonthespeciﬁcautomotiveandmaritime industries).Fig.5showsthetypeofproducts/industrieswherethe proposedguidelines,frameworksandmethodshavebeenapplied, highlightingthatthemostrelevantonesusedtoapplycircularDfX areElectricalandElectronicEquipment(EEE),photocopiers(and relatedtonercartridges)andautomotivesector.Thus,EEEs (con-sideringphotocopiersandtonercartridgesindustryasoneofits sub-group)andEndofLifeVehicles(ELVs)industriesseemmore sensitivetotheimplementationofDfXtoaddressCE.Thiscanbe explainedbythefactthattheyrepresentthetwomostimportant sourcesofwastesglobally,withanottobeneglectedpercentage ofhazardousmaterials.Atthesametime,theyinvolveproducts composedbyalargenumberofdifferentcomponentsand mate-rialsthatremainsunprocessedanddirectedtolandﬁlls(Ongondo etal.,2011;ZorpasandInglezakis,2012).

3.1. ExtantstateoftheartonDfXapproachessupportingthe adoptionofCircularEconomy

In this sub-section, the results of the systematic literature reviewabouttherelationshipamongDfXapproachesandCEare reported.Thesetof 31documentsselectedhavebeenanalysed (throughtheSLIPmethod(whichhelpstoSort,Label,Integrateand Prioritizekeyconcepts)(Maeda,2006))todetectandgroup: • thepurposesofusingDfXapproachestosupportandfosterthe

adoptionofCE,

• foreachofthesepurposes,whichability/iesis/areofmajor inter-est,

• theTripleBottomLine(TBL)perspectiveconsidered(sinceDfX approachestraditionallyaddresseconomicaspectsbutcanalso be oriented to enhance environmental and social ones) and throughwhichabilitieseachoftheseperspectiveisachievedby authors.

All the contributions were focused on understanding how designcancontributetothecirculartransitionthroughthe adop-tionofDfXapproaches.Themajority(15)wasaimedatimproving thedesignprocessunderacircularperspective,someofthem(8) wereorientedtofocusthedesignprocessattentiononcircular met-ricsandevaluations,fewofthemhadtheobjectivetosupportthe

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Table2

DfXpurposesfosteringcircularityadoption.

DfXpurpose Circulardesign improvement

Circulardesignmetrics andevaluation Circulardesign decision-support Designdriving circulartransition Circulardesign knowledge management Total 15 8 3 3 2 (Bakkeretal.(2014)); (Ceschinand Gaziulusoy(2016)); (Goetal.(2015)); (Morenoetal.(2016)); (PigossoandMcAloone (2017));

(vanderLaanand Aurisicchio(2019)); (Vanegasetal.(2018)); (Wahabetal.(2018)); (Sundin(2004)); (Hultgren(2012)); (Allwoodetal.(2011)); (Rose(2000)); (Peetersetal.(2012)); (Arnetteetal.(2014)) (Favietal.(2019))

(BoveaandPérez-Belis (2004));

(Mendozaetal. (2017));

(Rochaetal.(2019)); (Rossietal.(2016)); (VandenBergand Bakker(2015)); (ShuandFlowers (1999)); (DesaiandMital (2003));

(Mayyasetal.(2012))

(Gouldetal. (2017)); (Kuoetal.(2019)); (PozoArcosetal. (2018))

DeLosRiosand Charnley(2017); (Bhamra(2004)); (Rahitoetal. (2019)) (Favietal.(2016)); (Toxopeusetal. (2018))

decision-makingalongcirculardesignprocess(3),thetransition throughdesigntowardscircularity(3)andtheknowledge manage-mentprocessthroughoutcirculardesign(2).Table2reportssome detailsabouttheﬁnalsetof31papers.

AllthedetectedpurposesplayedbyDfXapproachesundera cir-cularperspective(seeFig.6below),havebeenanalysedinterms ofmeanproposed/used(method,tool,framework,guidelines, rec-ommendations, literaturereview, model) toaddress circularity, mainabilitiestobeaddressed(andrelatedsecondaryabilitiesand features),TBLperspective consideredtoaddress circularityand researchgapstobeﬁlled.

Indeed,eachdocumenthasbeenanalysedunderatwofold per-spectivewiththeDfXlensestounderstandhowtheseapproaches havebeenusedtoaddressCEsofar.Thedocumentsselectedhave beenanalysed not only tounderstand for which purposes DfX approacheshavecontributedtoCEadoption(leadingtothe clas-sificationpresentedinFig.6above)butalsotodefinewhichDfX abilitieshavebeenconsideredtoaddressthesedifferentpurposes. TheDfXAbilityisbasedonthe“function”conceptexplainedby (Mitaletal.,2008),p.251).Theydefineafunctionastheabilityof aproduct“todosomething(performance),safely,reliably,inausable manner,inahigh-qualitymanner,withconcernformanufacturability andenvironmentfriendliness”.Abilitiesarehencethoseprinciples throughwhichthefunctioncanbeexplicatedandexplainedand representswhat precisely the DfX approach addresses (Huang, 1996;SassanelliandPezzotta,2019).Giventhehuge amountof approaches in extantliterature, abilities reported in theset of documentsanalysedwerefirstgroupedinmainandsecondary abil-itiesorientedtoachievecircularity.Finally,onlythemainabilities havebeenconsideredandgroupedinthisanalysis(usingtheSLIP method(Maeda,2006))tosetthecategoriesofcircularDfXabilities. Theseabilitiesareclusteredin5mainclasses:

1SupplyChain(SC):ittakesaccountoftheroleoftheSCduringthe designphaseintermsofcoordination,collaborationand integra-tiontodelivercircularor/andsustainablevaluetothecustomer (LeeandBillington,1992),coveringthewholespectrumofvalue creationforbothbiologicalandtechnologicalcycles(Charnley etal.,2011).ItisdeclinedinapproachesasDesignfor:

-Designfor:SC;Circular/SustainableSC;SystemChange. 2Resource/energyefﬁciency:itconsiderstheontological

charac-teristicoftheCEparadigmofminimizingthenegativeeffects

of ﬁnite resources consumption, by focusing on intelligent designofmaterials,productsandsystems(TheEllenMacArthur Foundation,2015)tominimiseemissions,resourceuse, pollu-tionandwaste,andmaximisetheresourceefﬁciencyofmaterial assets (Stahel and Reday-Mulvey, 1981; Pearce and Turner, 1991).Itgathersapproachesas:

-DesignforResourceefﬁciencyandconservation(DfREf&C). 3Reliability:itincludesapproachesaimedatimprovingeitherthe

inner capacityof theproducttoaddressreliability andsafety throughouttheentirelifecycleorthoseonesorientedat slow-ingandextendingthelifecycletoprolongtheirusephase(e.g. throughmaintenance).Thiscategoryisdeclinedinapproaches as:

-DesignforSlowingLifecycle(DfSLC);DesignforLonglifeUse ofProducts(DfLLUoP);DesignforMaintenance(DfMa);Design forProduct-lifeextension(DfPLExt),

-DesignforReliability(DfRel)andDesignforSafety(DfSa). 4Multiple Life Cycle (MLC): this category considers all those

approachesaimedatenablingtheMLCofresources.Several cir-clesareenabledclosingtheloopandaddressingthesustainable useofresources.Bothbiologicalandtechnicalcyclesare con-sideredin thesevirtuousapproaches.Six mainsub-categories havebeendetected,mainlybasedoneitherthedifferentstrategy adoptedtoclosetheloop(e.g.disassemblyorremanufacturing orrecycling)ortheinnerproductspropertiesabletofosterthe adoptionofthesestrategies(e.g.modularityoreaseofaccess). Theyconsistinapproachesas:

-DesignforMultipleLifeCycles(DfMLC);futureproofdesign; technicalcycle;biologicalcycle;closed-loopPSS;easeof clean-ing/storage/access,

-DesignforDisassemblyandReassembly(DfD&Rea),

-Design for Remanufacturing (DfRem); Design for Remake (DfRema);DesignforRecovery(DfReco),

-DesignforRecycling(DfRecy), -DesignforEnd-of-Life(DfEoL),

-Designfor:Adaptability;Standardization;Compatibility; Mod-ularity;Upgradability.

5Sustainability:thiscategory isfunded onthetangledrelation betweensustainabilityandCE(Merlietal.,2018).Hereconverge alltheapproachesaddressingsustainability,declinedthroughout theTBL(WCED,1987)withitsthreefoldperspective(economic, environmental,social).

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Fig.6.SchemeofDfXpurposesfosteringCircularEconomyadoption.

-DesignforSustainability(DfSu), -DesignforEnvironment(DfE), -DesignforSocialResponsibility(DfSR).

Moreover,authorsconsiderrelevanttoprovideabriefoverview alsoofthesecondaryapproaches,reportingsomeexamples.From oneside,ontheproductlevel,emotionallydurabledesign,design forproductattachment,greenandeco-design,designfor sustain-ablebehaviour, cradle-to-cradle design and biomimicry design. Instead,fromaPSSperspective,PSSdesignforeco-efﬁciency,PSS designforsustainabilityandPSSdesignfortheBottomofthe Pyra-mid(BoP),designforsocialinnovation,systemicdesign,designfor systemsinnovationsandtransitions.Inaddition,designfor logis-tics,designforprocurement,designforreverselogisticcontributed toenrichtheSCcategory.Finally,otherapproacheswereaimed mainlyatstrengtheningthesustainableandenvironmentalaspect: radicalinnovationforsustainability,designforcascadeduse,design forenergyperformance,designfordematerialization,design for responsibleuser-behaviour,designforﬂexibility,designformass customization,designforchronicriskreduction,designforenergy conservation,design formaterialconservation,designforwaste minimization&recovery.

Furthermore,itisworthtoanalysethetwofoldDfX-CEresearch contextthroughthetypeofresearchesconductedandthe contribu-tionsproposedbyresearchers(Table3).Ingeneral,mostresearches conductedweremostlytheoretical.Indeed,justoneoftheﬁveDfX purposecategories, CircularDesignKM,is characterizedonlyby practicalcontributions.Inthiscaseonlymethodsandtoolswere proposedtofosteraneasiersharingandutilizationofdesign knowl-edge.Instead,inthecaseofCircularDesignImprovementcategory, themajorityofcontributionsweretheoretical,sometimes gather-ingasaresultguidelinesprovidedinliteratureandsometimealso proposingnewmethodstodeﬁnevaluesastheproductlifespan anddisassemblytimeortoimprovetheproductcharacteristicsfor easingrecyclingandremanufacturing.TheCircularDesignMetrics andEvaluationscategorymainlypresentsframeworksandmodels

toensureabetterimplementationofCErequirementsorto quan-tifythecostofjointsthroughouttheremanufacturingprocesses. IntheCircularDesignDecision-Supportcategory,literaturereviews andacasestudyconcurtoprovidenotonlya frameworkanda methodselectingthemostsuitablesustainabledesignstrategies andprovidinghintsonhow toimplementthembutalso recov-ery guidelines supportingthedecision-support process. Finally, intheDesignDrivingCircularTransitioncontributions,only theo-reticalassessmentswereconducted,providingliteraturereviews concerningtheresearchcontext.

In the following sub-sections, the set of 31 contributions selectedaredescribedbasedontheaggregatedimensionof anal-ysis,named DfXpurposesfosteringcircular adoption(shownin Fig.6).

3.1.1. Circulardesignimprovement

AsreportedinTable2,themostcommonpurposejustifyingthe adoptionofDfXtofosterandaddresscircularityistheimprovement ofthedesignofproducts/service/systemsfromacircular perspec-tive(Rose,2000; Sundin,2004; Allwoodet al., 2011;Hultgren, 2012;PeetersandDewulf,2012;Arnetteetal.,2014;Bakkeretal., 2014;Goetal.,2015;CeschinandGaziulusoy,2016;Morenoetal., 2016;PigossoandMcAloone,2017;Vanegasetal.,2018;Wahab etal.,2018;vanderLaanandAurisicchio,2019).

(Bakkeretal.(2014))exploredhowproductdesigncanmore proactivelyaddressproductlifeextension(throughlongerproduct life,refurbishmentand remanufacturing)andproductrecycling. BasedontheWasteFrameworkDirective,theyselectedthreemain strategies for product life extension and recycling: prevention, reuseandrecycling.Inordertoaddressoneofthesethree strate-gies,itisimportanttorealizehowtodeﬁneproductlifespanfrom bothanenvironmentalandeconomicperspective.Thechallenge istodeterminewhentoapplywhichproductlifeextension strat-egy.Forthisreason,theyproposedamethodologytodeterminethe optimalproductlifespan,appliedtotwocasestudiesonadomestic refrigeratorandalaptop.

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Table3

Typeofresearchesandcontributionsproposed.

DfXpurposesfostering circularadoption Authors

Researchtype Mean

Theoretical assessment Case studies Action research Method/tool Framework /model Guidelines Literature review CircularDesign Improvement (Bakkeretal.(2014)) x x (Ceschinand Gaziulusoy(2016)) x x (Goetal.(2015)) x x x (Morenoetal.(2016)) x x x

(PigossoandMcAloone (2017))

x x

(vanderLaanand Aurisicchio(2019)) x x (Vanegasetal.(2018)) x x (Favietal.(2019)) x x (Wahabetal.(2018)) x x (Sundin(2004)) x x (Hultgren(2012)) x x (Allwoodetal.(2011)) x x (Rose(2000)) x x (Peetersetal.(2012)) x x (Arnetteetal.(2014)) x x

TotalperDfXpurpose 10 3 2 4 1 6 5

CircularDesign Metricsand Evaluation

(BoveaandPérez-Belis (2004))

x x

(Mendozaetal.(2017)) x x

(Rochaetal.(2019)) x x

(Rossietal.(2016)) x x x

(VandenBergand Bakker(2015))

x x

(ShuandFlowers (1999))

x x

(DesaiandMital (2003))

x x

(Mayyasetal.(2012)) x x

CircularDesign Decision-Support

(Gouldetal.(2017)) x x

(Kuoetal.(2019)) x x

(PozoArcosetal. (2018))

x x

DesignDriving CircularTransition

DeLosRiosand Charnley(2017)

x x

(Bhamra(2004)) x x

(Rahitoetal.(2019)) x x

CircularDesignKM (Favietal.(2016)) x x

(Toxopeusetal.(2018)) x x

TotalofallDfXpurposes 19 6 6 10 6 7 11

(CeschinandGaziulusoy(2016))exploredhowDfSuapproach evolved,groupingthedesignapproachesproposedintheextant literature in fourinnovation levels: Product, PSS, Spatial-Social andSocio-TechnicalSystem.Tothisaim,theyassessedDfX guide-linesandtoolkitssupportingsustainableattitudes.Atproductlevel, emotionallydurable design and Design for productattachment weredefinedcomplementarytothemorebasicgreen and eco-design approaches. Moreover,Design for SustainableBehaviour addressestheproductimpactthroughoutitswholelifecycle,while cradle-to-cradledesignandbiomimicrydesignwereconsideredto contributetotheEoL.Inaddition,DesignfortheBaseofthe Pyra-mid(BoP)wassupposedtosupportsocialissues,mostlythrough PSS-basedBMsadoption(Emilietal.,2016).InthePSScontext, researchersconsideredenvironmentalandeconomicapproaches (as PSS design for eco-efficiency) and included also the social aspects(throughPSSDfSuandPSSDfBoP).Thespatial-sociallevel unveiledaneedfortechnologicalinnovationstobecomplemented by social innovations through approaches as design for social innovation. In this dimension also systemic design was intro-duced,focusing ontheconceptofwaste(materialsandenergy) flows,designedtobecomeinputstootherprocesses.Lastly,atthe

socio-technicalsysteminnovationlevel,DesignforSystems Inno-vationsandTransitionswasconsideredasthestrategicapproach toembodythePSSdesign.

Aswell,(Morenoetal.(2016))proposedaconceptual frame-work for CEdesign strategies starting from an analysis of the extantliteratureonDfSucombinedwithCBMs.BasedontheDfX approachestaxonomyby(DelosRiosandCharnley(2017)),they detectedﬁvemaincirculardesignstrategies:

1Designforcircularsupplies 2Designforresourceconservation 3DfMLC

4DfLLUoP 5DfSysC

AfterreviewingDfXapproachesandproposingtheiradoption asafundamentalmeantopursuethetransitiontowardscircular design,theyproposed10recommendationstobeconsideredwhen designingforaCE.

Instead, (Go et al.(2015)) analysed and groupedthe design guidelinescomingfromthoseDfXapproaches concurringtothe

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8 C.Sassanelli,A.Urbinati,P.Rosaetal./ComputersinIndustry120(2020)103245 deﬁnitionof DfMLC. They deﬁned DfMLC as a mixture of

eco-designstrategies(DfE,DfRem,DesignforUpgradability,DfA,DfDis, DesignforModularity,DfMaandDfRel)thattheymappedwith MLC options (reuse/remanufacturing/recycling) processes (core collection,inspection,disassembly,cleaning&storage, remedia-tion,reassembly,testing).Theyreportedthemainguidelinesper eachoftheseapproachesarguingthattheirconcurrentadoption cangroundthecirculardesignoffutureproducts.

(PigossoandMcAloone(2017)),throughasystematicliterature review,identiﬁed“designmethodsandtools”,“Product,serviceand systemdesign”and“DesignforX/DesigntoX”asthethreemain designtopicsintheCEcontext.ConcerningDfX,theyrecognized thekeyroleofsuchapproachesincirculardesign(impactingon differentaspectsascost,aestheticsandperformance),also reveal-ingtheroleofdigitaltechnologies, IoTandbigdataasenablers forCE.Moreover,alsointhiscasePSSseemedtobeapromising approachforCE,tobesupportedbysuitabledesignguidelinesand sustainabilityevaluationmethods.

SinceextantresearchesfocusedondevelopingPSSsthatnarrow andslowresourceﬂows(Bockenetal.,2016;Blomsmaetal.,2018) ratherthanclosingresourceloops,(vanderLaanandAurisicchio (2019))provided10guidelinesforthedesignofclosed-loopPSSs, groupedin4dimensions:statelifetime;governlifetime;intercept obsoletes;transitionobsoletes.

Based on the need raised in the EU action plan for theCE (EuropeanCommission,2015)todevelopstandardsonmaterial efﬁciencytosetdurability,reparabilityandrecyclability require-ments,(Vanegasetal.(2018))proposedamethod,“eDiM”(easeof DisassemblyMetric),aimedatcomputingthedisassemblytimeto measureeaseofdisassembly,comparealternativeproductdesigns andmeasurerecoverability.Beingtimeavalidmetricfor disassem-blymodelling,theycategorizeddisassemblytasksinsixcategories (tool change, identifyingconnectors, manipulation, positioning, disconnection, removing)to better understand which ones are themosttime-consumingandhowtheycouldbeimproved.(Favi etal.(2019))proposedaDfDmethodandtool,theLeanDfD,toaid designersandengineersintheimplementationofre-designactions forimprovingproductde-manufacturabilityandEoLperformances. Themethodology is composedof fourmain steps(target com-ponents,precedencies,liaisonsandproperties,disassemblytimes &costs).Quantitativelyassessingthedisassemblabilityand recy-clabilityofmechatronicproductsthroughsuitableindicators,the LeanDfDpackagecan:

• assessthedesigndecisions

• storeandclassifydisassemblydata(standardtimesand correc-tivefactorsofeachdisassemblyliaisonandoperation)tocreate valuableknowledge,usefulto:

-conducttime-basedanalysisandimprovethedisassemblability performanceoftargetcomponents

-estimatethequantitiesofmaterialsthatcouldbepotentially recycledattheproductEoL.

(Wahab etal. (2018)) performeda review of remanufactur-ingtoextendlifecycleofmarinestructures,presentingDfRemas theenablerforlifecyclereliabilityandsafety.Indeed,demanding awarrantytoproducts’originalspecification andrequiring for-malcertificationstoensurefunctionalityandsafetyperformances, remanufacturingcanbeconsideredthebestEoLrecoverystrategy. Inthiscontext,theydiscussedhowtheincorporationofDfRem con-tributestoenhancereliabilityandsafetyforlifecycleextensionin eachofthedifferentstagesofembodimentdesign.Inarchitecture design,architecturesmodularityensuresreliabilityandsafety dur-ingtheusephase,minimizingdesigncomplexityandfacilitating accessibility,partreplacementandmaintenance.Inconfiguration design,durablematerials,reliableandstandardpartsare

consid-eredtosupportandeasedisassemblyandreassembly,inspection and cleaning,repair and restoration.In parametricdesign, DfD, DesignforEasyCleaning,DesignforRestoration,Designforease ofinspection,wereselectedtoimprovetheremanufacturing per-formances.

(Sundin (2004)) focused on DfE and DfRem, not neglecting conflicts between different DfX approaches. He introducedthe RemPro-matrix,identifyingtheproductpropertiestobe consid-eredwhenaproducthastoberemanufactured(wearresistance, easeof: identification,verification,access, handling,separation, securing,alignment,stacking)andshowingtheirrelationshipwith the steps composing the remanufacturing process (inspection, cleaning,disassembly,storage,repair,reassembly,testing).Finally, inRef.(Sundinetal.,2009),inlightofthepreviousresearchthey underlinedhowtoadaptproducttoPSSwithalifecycleperspective inthedesignphase.

(Hultgren(2012))createdguidelinesanddesignstrategieson recyclabilitytosupportengineersindesigningproductsthatare easiertorecycle.Sheobtained4mainguidelines(mainlydealing with:hazardousmaterialsandcomponents;theireaseofaccess and removal; recyclable materials; connections enabling liber-ation) declined in a set of 14 design strategies. Indeed, these guidelinescanbeexplodedinseveraldesignstrategiescontaining morespeciﬁcpracticalDfRecyadvices.Sheinvolveddifferent con-cepts(suchasDfEandDfSu,DfDandDfReco)ingeneralguidelines toimprovetheenvironmentalperformanceofproducts.

(Allwoodetal.(2011))discussedfourmainstrategiesfor reduc-ingmaterialdemandthroughmaterialefﬁciency(longer-lasting products; modularization and remanufacturing; component re-use;designingproductswithless material)andreporteddesign guidelinessupportingremanufacturing,basedon(SundinandBras (2005))work.

(Rose(2000))proposedadesigntool,EoLDesignAdvisor(ELDA), usingsimpleproductcharacteristicstomakeEoLstrategydecisions basedondesigners’andproductmanagers’recyclingexperiences. Moreover,shedefinedsixEoLstrategies(reuse,service, remanu-facture,recyclingwithassembly,recyclingwithoutdisassembly, disposal) to map product characteristics withthe possible EoL treatmentoftheproduct.Shedetectedsixfinaltechnicalproduct characteristics(wear-outlife,technologycycle,levelofintegration, numberofparts,designcycle,reasonforredesign)becauseoftheir stronginfluenceovertheproductEoLstrategy.In(RoseandStevels, 2001),theEnvironmentalValueChainAnalysiswascombinedwith ELDA.ByanalysingthevaluechainsofexistingproductEoL sys-tems,theywereabletoidentifytheappropriateEoLstrategyand enhancesomeofthemastake-backandrecyclingsystems.

(Peetersetal. (2012))gatheredgeneraldesignguidelinesfor differentdemanufacturingstrategies,highlightingthatguidelines relatedtodisassemblyareoftenclashingwiththoseaimedat dis-mantling,smashing or shredding. However, alsoin this case it wasrecognized theimportance of fasteners for productstobe repaired,reconditionedorremanufacturedinviewofthe disassem-blyprocess(eithermanualorautomatedoractive).Theyconcluded categorizingthreedifferenttypesofproductstobeinvolvedinthe remanufacturingprocess:

• PSS-basedproducts(inwhichtheproviderisimpelledto imple-mentdesignimprovementtoeasethedemanufacturingprocess) • electronicproducts(inwhichnon-orsemi-destructive deman-ufacturingprocesses,throughactivefasteners,stronglyfacilitate multiplelifecyclesoftheproducts)

• productstobenotrepaired,remanufacturedorrefurbished(in whichthevalueofdesigntosupportdisassemblyisminor,and largeformlockingfastenersandlooseﬁtscanbeusedtoenact destructivedemanufacturingprocess)

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On the same line, (Arnette et al. (2014)) started from the considerationthat forproductssoldwithina PSS,in whichthe providerretainstheproductpropertyrights,therearedirect eco-nomic stimuli for manufacturers or retailers for implementing designimprovementswhichfacilitatedemanufacturingprocesses. Thus,theygroupedDfXapproachesinfourcategoriesunderthe DfSu umbrella.Under the economy dimensiontheyconsidered approachesas:SC,Logistics,ManufacturingandAssembly, Flex-ibility(MassCustomization,Modularity), QualityandReliability, Procurement,Supportability(Maintainability,Serviceability).The ecologydimensiongroupsapproachasDesignfor:Environment, ChronicRiskReduction,EnergyConservation,Material Conserva-tion,WasteMinimization&Recovery,Remanufacturing,Reuse& Recycling.ThetwofolddimensionEconomyandEcologywas com-posedbyDfDandDesignforReverseLogistic.Last,underanEquity perspective,DfSRwasconsidered.Thethreedimensionsof sustain-abilityseemtobeinterrelatedthroughtheirthreemainapproaches detectedbythe authors:DfSC (economic), DfE(environmental) andDfSR (social).In detail,theeconomicdimensioncollectsall thetraditionalDfXapproachesundertheconceptofDfSC, focus-ingonthesourcing,productionanddistributionprocesses.Atthis purpose,sincethedecisionoftheDfXcriteriatobeappliedare linkedtotheproductlifecyclephasestobestrengthened,DfX con-sideredin thetaxonomywerealsomappedbasedonﬁvemain lifecyclesub-phases(sourcing,production,distribution,use,EoL) andcombinedwiththebusinessstrategytobeadopted(low-cost leadership,productdifferentiation).

Table 4 shows that, when the purpose of DfX approaches is Circular designimprovement, researchers involvedall theﬁve macro-categoriesofDfXdetectedbutfocusingonMLCand sus-tainabilitycategories,mostlyadoptingDfRem/Rema/Reco,DfEand DfD&Rea.Ingeneralterms,theTBLperspectivewasalwaysfocused onenvironmentalaspects,sometimesrelatedtoeconomicaspects andfewtimeswiththesocialside.

3.1.2. Circulardesignmetricsandevaluation

(BoveaandPérez-Belis(2004))re-organizedfromaCE perspec-tive46designguidelinescomingfromtheeco-designframework (Bhamra,2004)andseveralDfXapproaches(DfE(Gertsakisetal., 2001),DfDis(DowieandSimon,1994),DfReco(Hultgren,2012), DfRem(Sundin,2004)).Inaddition,othernewdesignguidelines wereproposedandgatheredinfivemaincirculardesigngroups: extending life span, disassembling, product reuse, components reuse, and materialrecycling. Afterproviding a setof practical designguidelines,theyalsopresentedamethodologythatallows theanalysisofhowanexistingproductdesignmeetsthedesign guidelinesrequiredfromthecircular economy perspective.The methodologywas appliedontwelve case studies,defining two maincriteriatodefinecircularitydegree(marginofimprovement andrelevance).

(Mendozaetal.(2017))presentedaframework,Backcasting andEco-designfortheCircularEconomy(BECE),toensurethat businesses canimplement CE requirementsmore readily.They categorizedproductdesignandbusinessmodelstrategiesintwo mainactions,slowing(i.e.designforlong-lifeproducts,DfPLExt (DfMaandrepair,upgradabilityandadaptability,standardization andcompatibility,andDfD&Rea),andclosingresourceloops(i.e. designforatechnologicalcycle,designforabiologicalcycle,and DfD&Rea).

(Rochaetal.(2019))proposedananalyticalframeworkforDfSu models,distinguishingthestrategic,tacticalandoperationaldesign activitiesand linkingeach dimensionwithdesign management andcorporatesocialresponsibilityliteratures.Thecorporate sus-tainabilitymanagementanddesignmanagementweresuitableto buildaframeworkforanalysisoftheexistingselectedmodels,and

allowedtoexploreDfSuuseintopractice,atstrategic,tacticaland operationallevels.

(Rossietal.(2016))conductedareviewofeco-designmethods andtoolstoenableaneffectiveimplementationofCEin indus-trialcompanies.Amongtheothers,theysuggestedchecklistand guidelinesapproachtoquicklyevaluatetheproduct’s environmen-talprofileand tomakesuggestionstothedesign teamtosolve problemsduringthefirstdesignphases.DfXapproaches,usually used by thedesign team tomanage product-specific solutions, aresuggestedtobestronglyconsideredinthefieldofeco-design: DfD,DfRema,DfReco,DfRecyandtheDesignforEnergyEfficiency approaches.

(VandenBergandBakker(2015))providedaCEframeworkfrom aproductdesignperspective.InordertoextendthedesignforCE researchcontextbyalreadyexploredfieldsasdisassembly, reman-ufacturingandrecycling,theyperformedareviewoftheextantCE terminologyanddefinedfivemostdesign-relevanttopics:future proofdesign,DfD,DfMa,remakeandDfRecy.Twomainstreams weredetected.Ononeside,futureproofisaimedatmaking prod-uctslastlonger(involvingprinciplesasperformance,reliability, durability)oratprolongingtheiruse(throughupgradability, adapt-ability,timelessdesign,road-mapping,anticipatinglegislation).On theother side,disassembly canbe consideredalone (actingon connectionsorproductarchitecturethroughprinciplesaseaseof access,quickdisconnections,simplearchitectures,clarityof dis-assembly,etc.)orcombined.Whencombined,itcanbeaddressed eitherwithonlynon-destructivepractices,maintenanceforreuse of products(based onease ofcleaning, ease of repair/upgrade, onsiterepairabilityandupgradability)andremakeofcomponents (groundedonmodularity,reliabilityassessmentandreverse logis-tics),ordestructive/non-destructivepractices,i.e.recycle(toreuse materials,electronicsorconnectionsthroughafastandeasy detec-tion,modularity,useofnon-fixedconnections).

(ShuandFlowers(1999))investigatedbothliteratureand prac-ticetoexplore DfRem:in particular,itsconflictwithotherDfX approaches was assessed (focusingonDfMA, DfMa, and scrap-materialrecycling),reportingexamplesofdesigntipsineachof them.Theydetectedsixprocesses(disassembly,sorting,cleaning, refurbishment,reassemblyandtesting)toeaseremanufacturing, consideringfasteners andjoints design asstrategic inallthem. Finally,theyproposedaframework(toquantifyinallthese pro-cessesthecostofjoints,betterdescribingrepairactivitiesexecuted throughout remanufacture). (Desai and Mital (2003)) proposed a methodologythat assignstime-basednumericindices to sev-eral design factors(e.g. effortof manual forcefor disassembly, precisionrequiredfortoolplacement,weight,size,disassembled componentsmaterialandshape,handtools,etc),sofarconsidered onlyseparately inliterature.Theircalculationallowsthe detec-tionofdisassemblyanomalies(addressingdisassemblysequence planningoreconomicanalysis),designmodificationsandfinally alsodisassemblyimprovement.(Mayyasetal.(2012))conducteda reviewoftheextantcontributionsonvehicles’lifecycle,disposal andEoLanalyses,alsostudyingthesustainabilitymetricsusedto measuretheenvironmentalimpact.Thereviewcategorizedundera TBLperspectivetheliteratureintofourmainresearchareas(thelife cycleassessmentapproach,theEoLperspective,theDfX,the light-weightengineeringandmaterialselectionstudies).ConcerningDfX area, basedonapreviousstudyby(Jawahiretal.(2007)), they declinedDfSuinto4maingroups:DfMA,DfRecy/DfEoL (compris-ingDfD,DfRem,DfRecy,Designforreusability),DesignforMinimize MaterialUsage(durability,energyefficiency).

Table5illustratesthattosupportthecategoryCirculardesign metrics andevaluationresearchersdidnot focusonSCabilities. Instead, they concentrated their efforts on both enabling MLC (mainlythroughDfRem/Rema/RecoandDfD)andaddressing sus-tainability(mostlythroughDfE).Indeed, MLCandsustainability

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10 C. Sassanelli, A. Urbinati, P. Rosa et al. / Computers in Industry 120 (2020) 103245 Table4

Circulardesignimprovementcategory.

Authors Objective

MainAbilities TBL

SC Res/EnEffRel MultipleLifeCycle(MLC) Sustainability

Other Eco Env Soc C/SSC; SysC REf&C SLC;LLUoP; Ma;PLExt Rel&Sa MLC;FPD; TecC;BioC; CLPSS; EofC/S/A D&Rea Rem; Rema; Reco

Recy EoL Ad;St; Com;Mo; Upg Su E SR (Bakkeretal. (2014)) Todeterminethe optimalproduct lifespan. x x x x x x x (Ceschinand Gaziulusoy (2016)) TodeﬁneDfSu. x x x x (Goetal. (2015)) TodetectDfX approaches concurringtothe deﬁnitionof DfMLC. x x (Morenoetal. (2016))

Toguidethedesign processundera circulareconomy perspective. x x x x x (Pigossoand McAloone (2017)) Todeﬁnehow designcan contributetoCE. x Properties; Cost; Aesthetics; Perfor-mance x x

(vanderLaan andAurisicchio (2019))

Toprovide guidelinesforthe Designof closed-loopPSSs. x x x (Vanegasetal. (2018)) Tocomputethe disassemblytime. x x x (Favietal. (2019)) Tosupportthe implementationof re-designactions forimproving product de-manufacturability andEoL x x x x (Wahabetal. (2018))

Todiscussthelink among

remanufacturing, reliabilityand safetyforlifecycle extension. x x x x (Sundin (2004)) Toidentifythe productproperties tobeconsidered whenaproducthas tobe remanufactured x x x (Hultgren (2012)) Tosupport engineersin designingproducts thatareeasierto recycle.

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C. Sassanelli, A. Urbinati, P. Rosa et al. / Computers in Industry 120 (2020) 103245 11 Authors Objective MainAbilities TBL

SC Res/EnEffRel MultipleLifeCycle(MLC) Sustainability

Other Eco Env Soc C/SSC; SysC REf&C SLC;LLUoP; Ma;PLExt Rel&Sa MLC;FPD; TecC;BioC; CLPSS; EofC/S/A D&Rea Rem; Rema; Reco

Recy EoL Ad;St; Com;Mo; Upg Su E SR (Allwoodetal. (2011)) TosupportDfRem. x x

(Rose(2000)) Tousesimple product characteristicsto makeEoLstrategy decisionsbasedon recycling experienceswith designersand productmanagers. x x (Peetersetal. (2012)) Togathergeneral designguidelines fordifferent demanufacturing strategies. x x (Arnetteetal. (2014)) Toproposea taxonomyofDfX approachesinfour categoriesunder theDfSuumbrella.

x x x x x x x

Totalperability 2 2 2 1 4 4 4 3 1 0 3 4 1 1

8 15 2

Totalperaggregateabilities 2 2 3 16 8 1

l

SC=SupplyChain;C/SSC=Circular/SustainableSC;SysC=SystemChange;Res/EnEff=Resource/EnergyEfﬁciency;Ref&C=ResourceEfﬁciencyandConservation;Rel=Reliability;SLC=SlowingLifeCycle;LLUoP=LongLife UseofProducts;Ma=Maintenance;PLExt=ProductLifeExtension;Rel&Sa=ReliabilityandSafety;MLC=MultipleLifeCycle;FPD=FutureProofDesign;TecC=TechnicalCycle;BioC=BiologicalCycle;CLPSS=Closed-loop PSS;EofC/S/A=EaseofCleaning/Storage/Access;D&Rea=DisassemblyandReassembly;Rem=Remanufacturing;Rema=Remake;Reco=Recovery;Recy=Recycling;EoL=EndofLife;Ad=Adaptability;St=Standardization; Com=Compatibility;Mo=Modularity;Upg=Upgradability;Su=Sustainability;E=Environment;SR=SocialResponisibility;TBL=TripleBottomLine;Eco=Economic;Env=Environmental;Soc=Social.

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Circulardesignmetricsandevaluationcategory.

Authors Objective

MainAbilities TBL

SC Res/enEffRel MultipleLifeCycle(MLC) Sustainability

Other Eco Env Soc C/SSC; SysC REf&C SLC;LLUoP; Maint; PLExt Rel&Sa MLC;FPD; TecC;BioC; CLPSS; EofC/S/A D&Rea Rem; Rema;Reco

Recy EoL Ad;St; Com;Mo; Upg Su E SR (Boveaand Pérez-Belis (2004)) toassessifan existingproduct meetsthedesign guidelinesfroma CE perspec-tive+guidelines. x x x x x x (Mendozaetal. (2017)) toensurethat businessescan implementCE requirementsmore readily. x x x x x (Rochaetal. (2019)) toanalyzeDfSu models. x x x x (Rossietal. (2016)) tosuggestchecklist andguidelines approachto quicklyevaluate theproduct’s environmental proﬁle. x x x x

(VandenBerg andBakker (2015))

todeﬁneﬁvemost design-relevant topics. x x x x x (Shuand Flowers (1999)) toquantifyinall thesix remanufacturing sub-processes (disassembly, sorting,cleaning, refurbishment, reassemblyand testing)thecostof joints. x x (Desaiand Mital(2003)) toassign time-based numericindicesto severaldesign factors. x x (Mayyasetal. (2012)) tomeasurethe environmental impact. x x x x

4 6 2

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werethemostrecurrentability’scategories.FromaTBL perspec-tive,environmentaland economic assessmentswere supported morethansocialones.

3.1.3. Circulardesigndecision-support

Basedonthefactthattherearemanydesignstrategies provid-ingpracticalwaystoembedsustainabilityonproductsfromthe beginningofthelifecycle,Gouldetal.(2017)proposeda decision-supportprototypetochooseamongthem.Inordertodothis,they conductedaliteraturereview,analysingandselectingthemain potentialstrategiesfromsustainableproductdevelopment litera-ture.Asaresult,theycameupwithsixgroups:PSSDfSu,DfRem, designforsustainablebehaviour,DfBoP,designforsustainableSC, anddesignforsocialinnovation.

(Kuoetal.(2019))proposedadecision-makingmodelto eval-uate and implement sustainable PSSs. Comparing the cost of additionaldurabilitywiththeresidualvalueoftheproductatthe endoftheleaseproduct,themodeltracksbothproductdesignand life-cyclecostanalysis.Designplaysastrategicroleinsustainable PSSdesign,aimingatminimizingnegativeenvironmentalimpacts throughresourceusagereduction,materialrecyclingandreusingof theproducts.Indeed,themodelwantsalsotostrengthenthoseDfX strategiesembeddedintotheproductdesignconcurringtoaddress sustainablePSSs,mainlyDfMA,DfD,DfRel,Quality,Modularityand Variety.TheseDfXstrategies,combinedwithmathematical mod-els,couldsupporttheestimationofproduct’sproﬁtandprovide designsuggestionsstrengtheningthecradle-to-cradleprinciplein sustainablePSSs.

(PozoArcosetal.(2018))exploredtheexistingdesign strate-gies,guidelinesandproductfeaturesenablingfunctionalrecovery operations(asrepair,refurbishingorremanufacturing).Theyalso presenteda categorizationof functionalrecovery guidelinesfor productdesignsincetheyidentiﬁedtheneedtoplanfor recov-eryatearlydesignstages.Guidelineshavebeengroupedin4main classes:

• easeofcleaningsupportstheusephase • easeofdiagnosisreferstophysicalinspection

• disassembly and reassembly refers to non-invasive ways to implementrepairingandcleaning

• easeofstoragereferstokeepvaluablepartsforfutureusage Table6concernsthecategoryCirculardesigndecision-support: it shows a lack of focus on resource efﬁciency abilities. Here, researchersconcentratedtheireffortsonbothenablingMLCand addressingsustainability,withasocialfocus.Indeed,MLCand sus-tainabilitywere themost recurrent ability’scategories. Indeed, fromaTBLperspective,socialapproacheswerequiteintegrated toenvironmentalandeconomicones.

3.1.4. Designdrivingcirculartransition

DeLosRiosandCharnley(2017),withtheaimofdepicting suc-cessfulsustainableandCEpracticesbeingimplementedinindustry, operatedaclassiﬁcationoftheDfX/methodssupportingthethree typicaldesignstrategiesumbrellaterms:

1Designforlifecycle,aimedat:

aMultiplelifecycles/cradletocradle:Designforcascadeduse, DfRecy,DfRem

bLongerlifecycles:DfRel,DfMa,DesignforReuse

2DfE (preventive conservation of material and energy): biomimicry,DfMA,DfSC

3Whole-systemdesign:radicalinnovationforsustainability (Bhamra(2004))exploredtheliteratureconcerningeco-design. They identiﬁed several factors impelling companies, internally

and externally, to pursue eco-design (cost savings, legislative regulations, competition, market pressure, industrial customer requirements,innovation,employeemotivation,company respon-sibility, communications) and reviewed the extant theory and practiceofeco-design.

(Rahitoetal.(2019))providedanoverviewonthecharacteristics of theexisting Additive Manufacturing(AM)technology, focus-ingonthepotentialofDirectEnergyDepositiontechnologyfor repairandrestorationofremanufacturablecomponentsthatcan bereturnedasiftheywereinnewconditionor regeneratedto matchtheoriginalspeciﬁcation.Inthisdirection,theysuggested thedevelopmentofdesignguidelinesforrestorationof remanu-facturableproductsusingAM.

Table7concernsthecategoryDesigndrivingcirculartransition. Researchers neglectedto consider approaches belonging toSC, ReliabilityandResourceEfﬁciencycategories,focusingoneither broaderandquiteconsolidatedabilitiesasDesignforLifecycle, Sus-tainability,Environment,WholeSystemdesignornewapproaches asDesignforAMtosupportDfRem.Contributionsfocusedmainly ontheenvironmentalaspects.

3.1.5. Circulardesignknowledgemanagement

(Favietal.(2016))raisedtheneedtostrengthenthe connec-tionsbetweentheproductdesignand EoLphase.Indeed,sofar approachesasDfRem,DfRecyandDfDareonlytheoreticalconcepts withfewapplicationswithinarealindustrialcontext.Indeed,the knowledgeofdismantlersandrecyclingcentresisnotcodiﬁedtobe usedbydesignersforthere-designofproducts:evenifthiskindof designknowledgewouldbepotentiallyadvantaging,anapproach toformalizeitinpracticalguidelinesisstillmissing.Forthisreason, theyproposeamethodtogatherknowledgeandexpertisefrom dismantlerandremanufacturingcentreswithafocusonthe dis-assemblyprocessesinordertobeusedduringtheproductdesign phase:theideaisthattheresultingknowledgecanbereusedfor boththespeciﬁccomponentbutalsofortheotherpartsassembled withthoseelements.

(Toxopeuset al. (2018))developed a design support tool to provide to designers and engineers with design guidelines for developmentdecisions. Theylinkedproduct characteristicsand reversecycleprocesses(reuse,refurbish,remanufacture,recycle) throughadisassemblylevel(product,module,component, mate-rial)tofostertheresourcecirculationstrategy.

Table8 describestheCircular DesignKnowledgeManagement category.Thetwocontributionsmainlycomposingthiscategory mainlyusedapproachesaimedatenablingtheMLC,andinaminor wayalsoatslowinglifecycleandimprovetheresourceefﬁciency. Theenvironmentalperspectiveisdominantinthiscategory. 4. Discussion

Wrappinguptheresultsofthisresearch,authorsdetectedfive mainpurposeslinkedtotheapplicationofDfXapproachestofoster CEadoption:CircularDesignImprovement,CircularDesignMetrics andEvaluation,CircularDesignDecision-Support,DesignDriving Cir-cularTransition, CircularDesign KM.In thedocumentsanalysed, researcherscitedandinvolvedseveralDfXapproachestoaddress thesefivemaincircular designpurposes.Duetothehigh num-berofapproachesandabilitiesused,inthisresearchtheauthors decidedtodividethemin twocategories(mainandsecondary) andtookinconsiderationfortheiranalysisonlythemainones. ThemainapproacheshavebeengroupedinfivemainDfXabilities categories(SC,Resource/EnergyEfficiency,Reliability,MLC, Sustain-ability): they have the aim of synthesizing the multiplicity of wordsemployedtopursuethesameabilityunderaCE perspec-tive.However,alsoabriefoverviewofthesecondaryapproaches

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Circulardesigndecision-supportcategory.

Authors Objective

MainAbilities TBL

SC Res/enEff Rel MultipleLifeCycle Sustainability

Other Eco Env Soc C/SSC; SysC REf&C SLC; LLUoP; Maint; PLExt Rel& Sa MLC; FPD; TecC; BioC; CLPSS; EofC/S/A D&Rea Rem; Rema;Reco

Recy EoL Ad;St; Com; Mo; Upg Su E SR (Gouldetal. (2017)) tochooseamong manydesign strategies providingpractical waystoembed sustainability x x x x Sustainable behavior; DfBoP;social innovation. x x x (Kuoetal. (2019)) toevaluateand implement sustainablePSSs x x x DfMA;Quality x x (PozoArcos etal.(2018)) functionalrecovery guidelinesfor productdesign x x

2 2 1

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C. Sassanelli, A. Urbinati, P. Rosa et al. / Computers in Industry 120 (2020) 103245 15

Designdrivingcirculartransitioncategory.

Authors Objective

MainAbilities TBL

SC Res/enEff Rel MultipleLifeCycle(MLC) Sustainability

Other Eco Env Soc C/SSC; SysC REf&C SLC;LLUoP; Maint; PLExt Rel&Sa MLC;FPD; TecC;BioC; CLPSS; EofC/S/A D&Rea Rem; Rema;Reco

Recy EoL Ad;St; Com;Mo; Upg

Su E SR

DeLosRiosand Charnley (2017) touse DfX/methodsto supportCE. x x Whole-system design x (Bhamra (2004)) todetectfactors impelling companies, internallyand externally,to pursueeco-design. x x x (Rahitoetal. (2019)) todevelopdesign guidelinesfor restorationof remanufacturable productsthrough theuseofAM.

x DfAM x

1 3 0

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Circulardesignknowledgemanagement.

Authors Objective

MainAbilities TBL

SC Res/enEff Rel MultipleLifeCycle(MLC) Sustainability

Other Eco En Soc C/SSC; SysC REf&C SLC;LLUoP; Maint; PLExt Rel&Sa MLC;FPD; TecC;BioC; CLPSS; EofC/S/A D&Rea Rem; Rema;Reco

Recy EoL Ad;St; Com;Mo; Upg Su E SR (Favietal. (2016)) togather knowledgeand expertisefrom dismantlerand remanufacturing centerswitha focusonthe disassembly x x x x (Toxopeusetal. (2018)) toprovideto designersand engineerswith designguidelines fordevelopment decisionstolink product characteristicsand reversecycle processes x x x x x x

0 2 0

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Table9

DfX,purposesandabilitiesunderaTBLperspective:ageneralview.

DfXpurpose Numberofdocuments MainAbilities TBL SupplyChain Resource/

energy efﬁciency

Reliability Multiple LifeCycle

SustainabilityOther Economic Environmental Social

CircularDesign Improvement 15 2 2 3 15 8 1 8 15 2 CircularDesign Metricsand Evaluation 8 0 1 2 14 3 0 4 6 2 CircularDesign Decision-Support 3 1 0 1 5 2 2 2 2 1 DesignDriving CircularTransition 3 0 0 0 2 1 2 1 3 0 CircularDesignKM 2 0 1 1 6 0 0 0 2 0

Totalperaggregateabilities 3 4 7 42 14 5 15 28 5

wasprovided,ﬁndingapproachesfocusingspeciﬁcallyoneither

theproductorthePSSdevelopment.Manyofthemcontributed

totheSCmaincategoryandotherstothesustainability

(speciﬁ-callyonthematerials/energy/wastemanagementandreduction).

Inaddition,thedocumentswereassessedalsointermsofTBL

per-spectiveofsustainability.Thiswasdonetounveilwhichlenseshad

beenusedwhileadoptingspeciﬁcDfXabilitiestoaddressacertain

purposethroughcirculardesign.Thesedimensionsofanalysisare

allwrapped-upinTable9.Fromtheresultsshowninthetable,it

standsoutintheeyesthatthemostimportantpurposetoaddress circularitythroughDfXapproachesistheimprovementof prod-ucts/services/PSSsdesign(with15of31contributions).Concerning theDfXabilities,themostusedtoachieveCEarethoseorientedto MLC,pushingtheconceptoflifecyclefromasingledimensionto multiplecircularcycles. Finally,intermsofTBLperspective,the environmentalaspecthasbeenthemostcommonone,whilethe social onehasbeen quiteneglected(asalready stated in some recentliteraturereviewsonCE,e.g.(Rosaetal.,2019b).Morein detail,observingtheresultsfromTable9,theDfXapproachesmore usedtoenablecircularityareDfRem/Remake/Recoincouplewith DfD&Rea.Afterthem,inthesameabilitycategoryofMLC,some attentionhasbeendedicatedalsoonapproaches aimedatboth closingthelifecycleloop(asfutureproofdesign,Designfor Lifecy-cle(multiple,closed-loop,technicalorbiological)),andslowingthe lifecycleofsolutions(asDfMaandDfPLExt).Ontheotherside,also approachesasDfEandDfSudeservedafairattention:however,they wereusedasageneralandwidecategoryforconsideringa mul-tiplicityofdifferentmorespeciﬁcfunctionalitiestobeaddressed underacircularperspective.Finally,onlyfewattemptsweredone toconsiderthroughDfXinthecirculardesignalsoabilitiesasSC, thesocialsideofsustainability,resourceefﬁciencyandthe modu-larity/adaptability/upgradabilityofproducts.Theseapproachesare surelythoseneedingmoreeffortstobedevelopedextensively.

Finally,onceassessed anddiscussedthestateof theart and detected theopportunities, some comments about the gaps in theresearchcontextanalysedaregraspedfromTable10.Aspects claimingfurtherinvestigationintermsofamoreeffective tran-sitionfromlineartocirculardesignthroughtheadoptionofDfX approacheshavebeendetectedandgrouped,alsointhiscase,in5 macro-classes:

1Hybridstrategiesandapproaches:

• eithertopursuebothcostanddifferentiationstrategies, • ortoaddressbothproviderproductdesignanduserbehaviour, • ortointegratedifferentcircular designguidelinesinhybrid

approaches.

ThiskindofgapsaremainlypresentintwoDfXpurposes categories (Circular Design Improvement and Circular Design

MetricsandEvaluation),showingthattheeaseofcirculardesign isstronglylinkedtotheneedofsuchhybridapproaches provid-ingconcurrentlydifferentperspectivessometimesalsounder thesameDfXabilityumbrella.

2Method/Tool:

• tosupportdesigntoreduceenvironmentalimpactandexploit CEpotential,

• tosupportdesigndecisionmakingtowardscircularBM, quan-titativelyassessingcircularity(eventuallyincludinglegislation parameters),

• toprovidedetailedDfXguidelineswithalifecycleperspective, • todeﬁneatrade-offamongneededfunctionalitiesandselect

themostsuitableapproachestofostersustainability/CE, • tounderstandlimitationsofsingleapproachesand

revolution-izethePSSdesignprocess.

Thisisbyfarthemostrecurringcategoryofgapsinallthe fiveDfXpurposecategories,apartDesignDrivingCircular Tran-sition.Indeed,newDfXmethodsandtoolsareneededtosatisfy quiteheterogeneousissues.Theyareneededeitherto practi-callysupportdesigndecision-making process(alsoaidedby quantitativelyindicators)ortofindabalanceamongthe sev-eralDfXabilitiesexistingortounveiltheirsinglelimitations. Sometimes,theycanbealsorequiredtocompletelyrebuildand restructurethedesignprocessofproductorPSSs.Thiscategory ofneedisvalidifreferredeithertothegeneralcontextofDfX adoptioninthedesignprocessofnewproducts/services/PSSs ortospecificallysupportamoreproficientexploitationofCE potentialsthroughdesign.

3DesignKnowledgeandcompetencies:

• todevelopmoreextensivelycircularDfXapproaches andto generatesuitableguidelines.

Suchknowledgeisstronglyneededtoenhancebothcircular designandmetricsandevaluationprocesses.Itisalsostrategic fortheDfXpurposecategoryDesignDrivingCircularTransition: indeed,asetofnewcapabilities,todesignsustainablesolutions and ofnew knowledge,areneeded asa guidancefor man-ufacturingcompaniesseekingtotackleclimatechange.Also newdesignknowledgerelatedtonewtechnologies(asAM) arestronglyrequiredtoguidethejointpursuittowardsCEand Industry4.0.

4Technology:

• tomakeproductdesigninformation/KWavailablealongtheSC topursueacertainBMthrougharobustinformationsystem andsingleinputdatasheet,

• to integrate DfX methods/tools with: KM systems (aiding designersinthealternativeproductsolutionsdeﬁnition)and CADsystems(tosupporttheautomaticidentiﬁcationofthe differentproductlevels(throughthetopologicalanalysisof product3Dgeometry)andtoreducemanualinputs),

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GapsofDfXapproachesinCEresearchcontext. DfXpurposes

fostering circular economy adoption

Authors GapsCategories

Hybridstrategiesandapproaches Method/Tool DesignKW & compe-tencies

Technology Designstrategies

topursue costand differentia-tion strategies toaddress provider product designand user behavior tointegrate different circular design guidelines inhybrid approaches toreduce environ-mental impactand exploitCE through design tosupport design decision making towards CBM toprovide detailed DfX guidelines witha lifecycle perspective todefinea trade-off among functionali-tiesand selectthe most suitable sustain-able/circular ones todetect single approaches limitations to revolu-tionizePSS design process todevelop more extensively circular DfX approaches andto generate suitable guidelines tomake design informa-tion/KW available alongthe circularSC through robust informa-tion system, CADand single inputdata sheet todevelop new tech-nologiesto exploitCE potentiali-ties tofoster take-back andreverse logistics, toquantify thevalueof resources alongthe MLC todefine the usefullife of products todefine whichtype of products, needa specificEoL abilityand its economic convenience Circular Design Improve-ment (Bakkeretal. (2014)) x (Ceschinand Gaziulusoy(2016)) x (Goetal.(2015)) x (Morenoetal. (2016)) x (Pigossoand McAloone(2017)) x x

(vanderLaanand Aurisicchio(2019)) x x (Vanegasetal. (2018)) x (Favietal.(2019)) x (Wahabetal. (2018)) x (Sundin(2004)) x (Hultgren(2012)) x x (Allwoodetal. (2011)) x (Rose(2000)) x (Peetersetal. (2012)) x (Arnetteetal. (2014)) x x x x x TotalperDfX purposeper gap 1 1 0 1 3 2 2 1 3 2 0 1 1 2 2

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C. Sassanelli, A. Urbinati, P. Rosa et al. / Computers in Industry 120 (2020) 103245 19 DfXpurposes fostering circular economy adoption

topursue costand differentia-tion strategies toaddress provider product designand user behavior tointegrate different circular design guidelines inhybrid approaches toreduce environ-mental impactand exploitCE through design tosupport design decision making towards CBM toprovide detailed DfX guidelines witha lifecycle perspective todefinea trade-off among functionali-tiesand selectthe most suitable sustain-able/circular ones todetect single approaches limitations to revolu-tionizePSS design process todevelop more extensively circular DfX approaches andto generate suitable guidelines tomake design informa-tion/KW available alongthe circularSC through robust informa-tion system, CADand single inputdata sheet todevelop new tech-nologiesto exploitCE potentiali-ties tofoster take-back andreverse logistics, toquantify thevalueof resources alongthe MLC todefine the usefullife of products todefine whichtype of products, needa specificEoL abilityand its economic convenience TotalperDfX purposeper gapcategory 2 9 3 2 6 Circular Design Metrics and Evaluation (Boveaand Pérez-Belis(2004)) x x x (Mendozaetal. (2017)) x x x x x x (Rochaetal. (2019)) x x (Rossietal.(2016)) x

(VandenBergand Bakker(2015))

x x

(ShuandFlowers (1999)) (DesaiandMital (2003)) (Mayyasetal. (2012)) x TotalperDfX purposeper gap 0 0 2 2 2 1 2 1 4 0 1 0 0 0 0 TotalperDfX purposeper gapcategory 2 8 4 1 0 Circular Design Decision Support (Gouldetal. (2017)) x (Kuoetal.(2019)) x

(PozoArcosetal. (2018)) x TotalperDfX purposeper gap 0 0 0 0 0 0 2 0 0 0 0 0 0 0 1

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20 C. Sassanelli, A. Urbinati, P. Rosa et al. / Computers in Industry 120 (2020) 103245 Table10(Continued) DfXpurposes fostering circular economy adoption

topursue costand differentia-tion strategies toaddress provider product designand user behavior tointegrate different circular design guidelines inhybrid approaches toreduce environ-mental impactand exploitCE through design tosupport design decision making towards CBM toprovide detailed DfX guidelines witha lifecycle perspective todefinea trade-off among functionali-tiesand selectthe most suitable sustain-able/circular ones todetect single approaches limitations to revolu-tionizePSS design process todevelop more extensively circular DfX approaches andto generate suitable guidelines tomake design informa-tion/KW available alongthe circularSC through robust informa-tion system, CADand single inputdata sheet todevelop new tech-nologiesto exploitCE potentiali-ties tofoster take-back andreverse logistics, toquantify thevalueof resources alongthe MLC todefine the usefullife of products todefine whichtype of products, needa specificEoL abilityand its economic convenience TotalperDfX purposeper gapcategory 0 2 0 0 1 Design Driving Circular Transition

DeLosRiosand Charnley(2017) x (Bhamra(2004)) x (Rahitoetal. (2019)) x x TotalperDfX purposeper gap 0 0 0 0 0 0 0 1 2 0 1 0 0 0 0 TotalperDfX purposeper gapcategory 0 1 2 1 0 Circular DesignKM (Favietal.(2016)) (Toxopeusetal. (2018)) x x TotalperDfX purposeper gap 0 0 0 1 0 0 0 0 0 1 0 0 0 0 0 TotalperDfX purposeper gapcategory 0 1 0 1 0

Totalpergap 1 1 2 4 5 3 6 3 9 3 2 1 1 2 3

Totalpergap category