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Izakhiwo zepaneli zeSandwich zisetyenziswa ngokubanzi kumashishini amaninzi ngenxa yeempawu zabo eziphezulu. I-interlayer yezi zakhiwo yinto ebaluleke kakhulu ekulawuleni nasekuphuculeni iimpawu zabo zomatshini phantsi kweemeko ezahlukeneyo zokulayisha. Izakhiwo zeConcave lattice ngabaviwa abagqwesileyo bokusetyenziswa njengezihlanganisi kwezo zakhiwo zesandwich ngenxa yezizathu ezininzi, ezizezi, ukulungelelanisa ukuqina kwazo (umz., umlinganiselo wePoisson's kunye ne-elastic stiffness values) kunye ne-ductility (umz., ukuqina okuphezulu) ukwenza lula. Iimpawu zomlinganiselo wamandla obunzima zifezekiswa ngokulungelelanisa kuphela izinto zejometri ezenza iyunithi yeyunithi. Apha, siphanda impendulo ye-flexural ye-3-layer concave core sandwich panel usebenzisa uhlalutyo (okt, ithiyori ye-zigzag), i-computational (okt, i-finite element) kunye neemvavanyo zovavanyo. Sikwahlalutye ifuthe leeparamitha ezahlukeneyo zejiyometri zolwakhiwo lwelattice econcave (umzekelo, i-engile, ubukhulu, ubude beyunithi yeseli ukuya kumlinganiselo wobude) kwindlela yokuziphatha komatshini ngokubanzi kwesakhiwo sesandwich. Sifumanise ukuba iziseko ezingundoqo ezinokuziphatha kwe-auxetic (okt umlinganiselo ombi we-Poisson) ubonisa amandla aphezulu aguquguqukayo kunye noxinzelelo oluncinci lokucheba olungaphandle kwenqwelomoya xa kuthelekiswa ne-gratings eqhelekileyo. Iziphumo zethu zinokuvula indlela yophuhliso lolwakhiwo lobunjineli obuphezulu obunemigangatho yoyilo engundoqo ye-aerospace kunye ne-biomedical applications.
Ngenxa yamandla abo aphezulu kunye nobunzima obuphantsi, izakhiwo zesandwich zisetyenziswa ngokubanzi kumashishini amaninzi, kubandakanywa uyilo lomatshini kunye nezixhobo zemidlalo, i-marine, i-aerospace, kunye nobunjineli be-biomedical. Izakhiwo zeConcave lettice ngumgqatswa omnye onokuthi agqalwe njengomaleko angundoqo kwezo zakhiwo zidibeneyo ngenxa yomthamo wazo ophakamileyo wokufunxa amandla kunye neepropati zomlinganiselo wokomelela ukuya kobunzima1,2,3. Kwixesha elidlulileyo, iinzame ezinkulu zenziwe ukuyila izakhiwo zesandwich ezikhaphukhaphu kunye ne-concave lattices ukuphucula ngakumbi iimpawu zoomatshini. Imizekelo yoyilo olunjalo lubandakanya imithwalo yoxinzelelo oluphezulu kwiinqanawa zeenqanawa kunye nezinto ezithatha ukothuka kwiimoto4,5. Isizathu sokuba i-concave lattice structure ithandwa kakhulu, iyodwa kwaye ifanelekile kulwakhiwo lwepaneli yesandwich kukukwazi kwayo ukuzimela ngokuzimeleyo iimpawu zayo ze-elastomechanical (umzekelo ukuqina kwe-elastic kunye nokuthelekisa i-Poisson). Enye ipropathi enomdla enjalo yi-auxetic behaviour (okanye i-negative Poisson's ratio), ebhekisa kulwandiso olusecaleni lwesakhiwo selathisi xa isoluliwe ngokobude. Oku kuziphatha kungaqhelekanga kunxulumene noyilo lwe-microstructural yeeseli zayo ezisisiseko7,8,9.
Ukususela kuphando lokuqala Lakes 'kwimveliso amagwebu auxetic, iinzame ezibalulekileyo ziye zenziwa ukuphuhlisa izakhiwo porous kunye ratio10,11 embi Poisson kaThixo. Iijometri ezininzi ziye zacetywa ukufezekisa le njongo, ezifana ne-chiral, i-semi-rigid, kunye neeseli ezijikelezayo ezijikelezayo, i-12 yonke ibonisa ukuziphatha okungaqhelekanga. Ukufika kwe-additive production (AM, eyaziwa ngokuba yi-3D yoshicilelo) ubuchwepheshe bubuye buququzelele ukuphunyezwa kwezi zakhiwo ze-2D okanye ze-3D ze-auxetic13.
Ukuziphatha kwe-auxetic kubonelela ngeempawu ezizodwa zoomatshini. Ngokomzekelo, i-Lakes kunye ne-Elms14 ibonise ukuba i-auxetic foams inamandla aphezulu esivuno, amandla aphezulu okufunxa amandla, kunye nokuqina okuphantsi kune-foams eqhelekileyo. Ngokubhekiselele kwiipropathi eziguquguqukayo zomatshini we-auxetic foams, zibonisa ukuchasana okuphezulu phantsi kwemithwalo eguquguqukayo yokuphuka kunye nokuphakama okuphezulu phantsi koxinzelelo olucocekileyo15. Ukongezelela, ukusetyenziswa kwee-auxetic fibers njengezinto eziqiniswayo kwii-composites ziya kuphucula iimpawu zabo ze-mechanical16 kunye nokuchasana nomonakalo obangelwa yi-fiber stretch17.
Uphando luye lwabonisa ukuba ukusebenzisa i-concave auxetic structures njengengundoqo yezakhiwo ezidibeneyo ezigobileyo kunokuphucula ukusebenza kwazo ngaphandle kwendiza, kubandakanywa ukuqina kwe-flexural kunye namandla18. Ukusebenzisa imodeli elayitiweyo, kuye kwaphawulwa ukuba i-auxetic core inokunyusa amandla okuphuka kweepaneli ezidibeneyo19. Iimbumba ezinemicu ye-auxetic zikwathintela ukwanda kokuqhekeka xa kuthelekiswa neentsinga eziqhelekileyo20.
U-Zhang et al.21 wenze umzekelo wokuziphatha kongquzulwano oluguqukayo lwezakhiwo zeeseli ezibuyayo. Bafumanise ukuba ukufunxwa kombane kunye namandla kunokuphuculwa ngokunyusa i-engile ye-auxetic unit cell, okukhokelela kwigrayiti enomlinganiselo ombi wePoisson. Bakwacebise ukuba iiphaneli zesangweji ze auxetic zingasetyenziswa njengezakhiwo ezikhuselayo ngokuchasene nemithwalo yempembelelo yesantya esiphezulu. I-Imbalzano et al.22 iphinde ichaze ukuba ama-auxetic composite sheets angachitha amandla amaninzi (oko kukuthi ngokuphindwe kabini) ngokusebenzisa i-deformation yeplastiki kwaye anokunciphisa isantya esiphezulu kwicala elingasemva nge-70% xa kuthelekiswa namaphepha e-ply single.
Kwiminyaka yakutshanje, ingqwalasela eninzi ihlawulwe kwizifundo zamanani kunye novavanyo lwezakhiwo zesandwich nge-auxetic filler. Olu phononongo luqaqambisa iindlela zokuphucula iimpawu zoomatshini zezi zakhiwo zesandwich. Umzekelo, ukujonga umaleko otyebileyo owaneleyo njengombindi wepaneli yesandwich kunokukhokelela kwimodyuli ephezulu esebenzayo yoMtsha kunomaleko oqinileyo23. Ukongezelela, ukuziphatha okugoba kwe-laminated beams 24 okanye i-auxetic core tubes 25 inokuphuculwa kunye ne-algorithm yokuphucula. Kukho olunye uphononongo kuvavanyo lomatshini lwezakhiwo ezandisiweyo zesandwich engundoqo phantsi kwemithwalo enzima ngakumbi. Umzekelo, ukuxinzelelwa kovavanyo lwee-concrete composite kunye nee-aggregates ze-auxetic, iipaneli zesandwich phantsi kwemithwalo eqhumayo27, iimvavanyo zokugoba28 kunye neemvavanyo zempembelelo yesantya esisezantsi29, kunye nohlalutyo lokugoba okungekho mgca kweepaneli zesandwich kunye ne-aggregates ye-auxetic esebenzayo esebenzayo30.
Ngenxa yokuba ukulinganisa kwekhompyuter kunye novavanyo lovavanyo loyilo loyilo luhlala ludla ixesha kwaye luxabisa kakhulu, kukho imfuneko yokuphuhlisa iindlela zethiyori ezinokubonelela ngokufanelekileyo nangokuchanekileyo ulwazi olufunekayo ukuyila i-multilayer auxetic core structures phantsi kweemeko zokulayisha ngokungenamkhethe. ixesha elifanelekileyo. Nangona kunjalo, iindlela zanamhlanje zokuhlalutya zineemida ezininzi. Ngokukodwa, ezi thiyori azichanekanga ngokwaneleyo ukuqikelela indlela yokuziphatha kwezinto ezixubeneyo ezidityanisiweyo kunye nokuhlalutya imidibaniso eyenziwe ngezinto ezininzi ezineempawu ezilastiki ezahlukeneyo.
Ekubeni le mizekelo yokuhlalutya ixhomekeke kwimithwalo esetyenzisiweyo kunye neemeko zomda, apha siza kugxininisa ukuziphatha okuguquguqukayo kweepaneli ze-sandwich eziphambili ze-auxetic. Ithiyori elinganayo yomaleko osetyenzisiweyo kuhlalutyo olunjalo ayinakuqikelela ngokuchanekileyo ukucheba kunye noxinzelelo lwe-axial kwiilaminates ezingenahomogeneous kakhulu kwiicomposites zesangweji ezinobunzima obuphakathi. Ngaphezu koko, kwezinye iithiyori (umzekelo, kwithiyori ecwangcisiweyo), inani leenguqu ze-kinematic (umzekelo, ukufuduka, isantya, njl.njl.) kuxhomekeke kakhulu kwinani leeleya. Oku kuthetha ukuba intsimi yentshukumo yoluhlu ngalunye inokuchazwa ngokuzimeleyo, ngelixa iyanelisa imiqobo ethile yokuqhubeka komzimba. Ke ngoko, oku kukhokelela ekuthatheni ingqalelo inani elikhulu lezinto eziguquguqukayo kwimodeli, nto leyo eyenza le ndlela ibize kakhulu. Ukoyisa le mida, sicebisa indlela esekwe kwithiyori ye-zigzag, udidi oluthile lwethiyori yamanqanaba amaninzi. Ithiyori ibonelela ngokuqhubekeka koxinzelelo lwe-shear kulo lonke ubuninzi be-laminate, uthatha ipateni ye-zigzag yokufuduka kwinqwelomoya. Ngaloo ndlela, i-theory ye-zigzag inika inani elifanayo leenguqu ze-kinematic kungakhathaliseki ukuba inani leengqimba kwi-laminate.
Ukubonisa amandla endlela yethu yokuqikelela indlela yokuziphatha kweepaneli zesandwich ezinemiqolo egobileyo phantsi kwemithwalo egotywayo, siye sathelekisa iziphumo zethu kunye neethiyori zamandulo (okt indlela yethu kunye neemodeli ezibaliweyo (okt izinto ezinokuphela) kunye nedatha yovavanyo (okt ukugoba ngamanqaku amathathu Iiphaneli zesandwich eziprintiweyo ze-3D). Ukuza kuthi ga ngoku, siqale safumana ubudlelwane bokufuduswa ngokusekwe kwithiyori ye-zigzag, kwaye emva koko safumana ii-equations ezisisiseko sisebenzisa umgaqo we-Hamilton kwaye sazisombulula ngokusebenzisa indlela ye-Galerkin.Iziphumo ezifunyenweyo sisixhobo esinamandla soyilo oluhambelanayo. iiparameters zejometri ze-sandwich panels ezine-auxetic fillers, ziququzelela ukukhangela izakhiwo ezinokuphuculwa kweempawu zomatshini.
Cinga ngepaneli yesandwich enemigangatho emithathu (umzobo 1). Iiparamitha zoyilo lwejiyometri: umaleko ophezulu \({h}_{t}\), umaleko ophakathi \({h}_{c}\) kunye nomaleko ongezantsi \({h}_{ b }\) ubukhulu. Siqikelela ukuba undoqo wolwakhiwo uqulathe ulwakhiwo lwelathisi enemingxuma. Ulwakhiwo luquka iiseli ezisisiseko ezilungelelaniswe ecaleni kwenye ngendlela ecwangcisiweyo. Ngokutshintsha iiparamitha zejometri zesakhiwo se-concave, kunokwenzeka ukuba utshintshe iimpawu zayo zomatshini (oko kukuthi, amaxabiso omlinganiselo wePoisson kunye nokuqina kwe-elastic). Iiparamitha zejometri zeseli esisiseko ziboniswe kwiMifanekiso. I-1 iquka i-engile (θ), ubude (h), ubude (L) kunye nobukhulu bekholamu (t).
Ithiyori ye-zigzag ibonelela ngoqikelelo oluchaneke kakhulu loxinzelelo kunye nokuziphatha koxinzelelo lwezakhiwo ezidibeneyo ezinobungqingqwa obuphakathi. Ukufuduswa kwesakhiwo kwithiyori ye-zigzag inamacandelo amabini. Inxalenye yokuqala ibonisa ukuziphatha kwepaneli yesandwich xa iyonke, ngelixa icandelo lesibini lijonga ukuziphatha phakathi kweengqimba ukuqinisekisa ukuqhubeka koxinzelelo lwe-shear (okanye into ebizwa ngokuba yi-zigzag function). Ukongeza, i-zigzag element iyanyamalala kwindawo yangaphandle ye-laminate, kwaye ingekho ngaphakathi kolu luhlu. Ngaloo ndlela, umsebenzi we-zigzag uqinisekisa ukuba uluhlu ngalunye lunegalelo kwi-deformation ye-cross-sectional deformation. Lo mahluko ubalulekileyo ubonelela ngonikezelo lomzimba oluyinyani ngakumbi lomsebenzi ogoso-goso xa kuthelekiswa neminye imisebenzi egosogoso. Imodeli yangoku eguquliweyo ye-zigzag ayiboneleli ngokuqhubekeka koxinzelelo lwe-chear enqamlezileyo ecaleni komgangatho ophakathi. Ke ngoko, indawo yokufuduka esekwe kwithiyori ye-zigzag ingabhalwa ngolu hlobo31.
kwinxaki. (1), k=b, c kunye no-t bamele umaleko ongezantsi, ophakathi nophezulu, ngokulandelelanayo. Ibala lokufuduswa kwendiza ephakathi ecaleni kweCartesian axis (x, y, z) yi (u, v, w), kunye nojikelezo olugobayo kwinqwelomoya malunga ne (x, y) umgca ohamba phambili ngu \({\ uptheta} _ {x}\) kunye \ ({\ uptheta}_{y}\). \({\psi}_{x}\) kunye \({\psi}_{y}\) yimiyinge yendawo yokujikeleziswa kwe-zigzag, kunye \({\phi}_{x}^{k}\\ left ( z \ekunene)\) kunye \({\phi}_{y}^{k}\khohlo(z\ekunene)\) yimisebenzi egosogoso.
I-amplitude ye-zigzag ngumsebenzi we-vector wempendulo yangempela yeplate kumthwalo osetyenzisiweyo. Banikezela ukulinganisa okufanelekileyo komsebenzi we-zigzag, ngaloo ndlela belawula igalelo elipheleleyo le-zigzag ekufudukeni kwinqwelomoya. Uxinzelelo lwe-chear ngapha kobukhulu bepleyiti lunamacandelo amabini. Inxalenye yokuqala yi-engile yokucheba, iyunifomu kubunzima be-laminate, kwaye icandelo lesibini ngumsebenzi ongaguquguqukiyo, ngokufanayo kubunzima bomaleko ngamnye. Ngokwale misebenzi engaguqukiyo, umsebenzi ogosogoso womaleko ngamnye ungabhalwa ngolu hlobo:
kwinxaki. (2), \({c}_{11}^{k}\) kunye \({c}_{22}^{k}\) zii-elasticity constants zomaleko ngamnye, kwaye u-h bubunzima bubonke be idiski. Ukongeza, \({G}_{x}\) kunye \({G}_{y}\) yi-avareji ye-avareji yokuqina komlinganiso we-coefficients, echazwe njenge-31:
Imisebenzi emibini ye-amplitude ye-zigzag (i-Equation (3)) kunye ne-kinematic variables emihlanu eseleyo (i-Equation (2)) yomyalelo wokuqala we-shear deformation theory yenza isethi ye-kinematics ezisixhenxe ezinxulumene nale ngqungquthela ye-zigzag plate theory variable. Ukucinga ukuxhomekeka komgca we-deformation kunye nokuthathela ingqalelo ithiyori ye-zigzag, intsimi ye-deformation kwi-Cartesian coordinate system inokufumaneka njenge:
apho \({\varepsilon}_{yy}\) kunye \({\varepsilon}_{xx}\) ziziphene eziqhelekileyo, kunye \({\gamma}_{yz},{\gamma}_{xz} \ ) kunye \({\gamma}_{xy}\) kukucheba.
Ukusebenzisa umthetho kaHooke kunye nokuthathela ingqalelo ithiyori ye-zigzag, ubudlelwane phakathi koxinzelelo kunye noxinzelelo lweplate ye-orthotropic enesakhiwo se-concave lettice inokufumaneka kwi-equation (1). (5)32 apho \({c}_{ij}\) i-elastic constant ye-stress-strain matrix.
apho \({G}_{ij}^{k}\), \({E}_{ij}^{k}\) kunye \({v}_{ij}^{k}\)} zisikwa amandla yimodyuli kumacala ahlukeneyo, imodyuli eNtsha kunye nomlinganiselo wePoisson. Ezi coefficients zilingana kuzo zonke iindlela zomaleko we-isotopic. Ukongezelela, kwi-nuclei ebuyayo ye-lattice, njengoko kuboniswe kwi-Fig. 1, ezi zakhiwo zingaphinda zibhalwe njenge-33.
Ukusetyenziswa komgaqo kaHamilton kwii-equations zentshukumo yepleyiti ye-multilayer ene-concave lattice core ibonelela ngee-equations ezisisiseko kuyilo. Umgaqo kaHamilton unokubhalwa ngolu hlobo:
Phakathi kwabo, δ imele umqhubi wenguqu, i-U imele amandla anokubakho, kwaye i-W imele umsebenzi owenziwe ngamandla angaphandle. Itotali yamandla anokubakho afumaneka kusetyenziswa i-equation. (9), apho uA engummandla wenqwelomoya ephakathi.
Ukucinga ukusetyenziswa okufanayo komthwalo (p) kwicala le-z, umsebenzi wamandla angaphandle unokufumaneka kule fomula ilandelayo:
Ukutshintshwa kwe-equation (4) kunye (5) (9) kunye nokubuyisela inxaki. (9) kunye (10) (8) kunye nokudibanisa ngaphezulu kobukhulu bepleyiti, i-equation: (8) ingaphinda ibhalwe ngolu hlobo:
Isalathiso \(\phi\) simele umsebenzi ogosogoso, \({N}_{ij}\) kunye \({Q}_{iz}\) zimikhosi ngaphakathi nangaphandle kwenqwelomoya, \({M} _{ij }\) imele umzuzu wokugoba, kunye nefomula yokubala ngolu hlobo lulandelayo:
Ukusebenzisa udibaniso ngamalungu kwinxaki. Ukutshintsha kwifomula (12) kunye nokubala i-coefficient of variation, i-equation equation yepaneli yesandwich inokufumaneka ngendlela yefomyula (12). (13).
Ii-equations zolawulo oluhlukileyo kwiipleyiti ezintathu ezixhaswa ngokukhululekileyo zixazululwa yindlela yeGalerkin. Ngaphantsi kokucingelwa kweemeko ze-quasi-static, umsebenzi ongaziwayo uthathwa njenge-equation: (14).
\({u}_{m,n}\), \({v}_{m,n}\), \({w}_{m,n}\),\({{\ uptheta}_) {\mathrm {x}}}_{\mathrm {m} \text{,n}}\),\({{\ uptheta}_{\mathrm {y}}}_{\mathrm {m} \text {,n}}\), \({{\uppsi}_{\mathrm{x}}}_{\mathrm{m}\text{,n}}\) kunye \({{\uppsi}_{ \ mathrm {y}} _ {\ mathrm {m} \ okubhaliweyo { , n}} } \) ezingaziwayo ezingaguqukiyo ezinokufunyanwa ngokunciphisa impazamo. \(\ overline{\ overline{u}} \khohlo({x{\text{,y}}} \ekunene)\), \(\ overline{\ overline{v}} \khohlo({x{\text {,y}}} \ ekunene)\), \(\ ngaphezulu kwe-intanethi{w}} \ ekhohlo ( {x {\ umbhalo {, y}}} \ ekunene) \), \ (\ ngaphezulu kwe-intanethi{\ ngaphezulu kwe-intanethi {{{\ uptheta}_{x}}} \ ekhohlo( {x{\ text{,y}}} \ ekunene)\), \(\ overline{\ overline{{\ uptheta}_{y} }}} \ekhohlo( {x{\ okubhaliweyo{, y}}} \ ekunene)\), \(\ ngaphezulu kwe-intanethi{\ ngaphaya{\ psi_{x}}}} \ ekhohlo ( {x {\ umbhalo {, y}}} \ ekunene)\) kunye \(\ ngaphezulu kwe-intanethi{\ ngaphaya{\psi_{y} }}} \ ekhohlo ( {x {\ okubhaliweyo {, y}}} \ ekunene) \) yimisebenzi yovavanyo, ekufuneka yanelise iimeko zemida eziyimfuneko. Kwiimeko zomda ezixhasiweyo, umsebenzi wovavanyo unokubalwa kwakhona ngolu hlobo:
Ukutshintshwa kweeequations kunika iiequations zealjibra. (14) kwii-equations ezilawulayo, ezingakhokelela ekufumaneni ii-coefficients ezingaziwayo kwi-equation (14). (14).
Sisebenzisa i-finite element modelling (FEM) ukulinganisa ikhompyutha-ukulinganisa ukugoba kwepaneli yesandwich exhaswa ngokukhululekileyo kunye nesakhiwo se-concave lettice njengondoqo. Uhlalutyo lwenziwa kwikhowudi yento yorhwebo (umzekelo, inguqulo ye-Abaqus 6.12.1). Izinto eziqinileyo ze-3D ze-hexahedral (C3D8R) kunye nokudibanisa okulula zisetyenziselwa ukulinganisa iileyile eziphezulu kunye nezantsi, kunye ne-linear tetrahedral elements (C3D4) zisetyenziselwa ukulinganisa i-intermediate (concave) ye-lattice structure. Senze uhlalutyo lobuntununtunu bemesh ukuvavanya ukuhlangana komnatha kwaye sagqiba kwelokuba iziphumo zokufuduswa zihlangane kowona bukhulu buncinci beempawu phakathi kwamacandelo amathathu. I-sandwich plate ilayishwe ngokusebenzisa umsebenzi womthwalo we-sinusoidal, ngokuqwalasela iimeko zomda ezixhaswa ngokukhululekileyo kwimida emine. Umgca we-elastic mechanical behaviour ithathwa njengemodeli yempahla eyabelwe yonke imigangatho. Akukho nxibelelwano luthile phakathi kweemaleko, zidityanisiwe.
Sisebenzise iindlela zoshicilelo ze-3D ukwenza iprototype yethu (okt. ipaneli yesangweji eprintiweyo ephindwe kathathu eprintiweyo) kunye noseto lwesiko lokulinga oluhambelanayo ukuze kufakwe iimeko zokugoba ezifanayo (umthwalo olinganayo p ecaleni kwendlela engu-z) kunye neemeko zemida (okt. ixhaswa nje). kucingelwa kwindlela yethu yokuhlalutya (umzobo 1).
Ipaneli yesandwich eprintwe kumshicileli we-3D iqulathe izikhumba ezibini (phezulu nasezantsi) kunye nombindi welattice econcave, imilinganiselo yazo iboniswe kwiTheyibhile yoku-1, kwaye yenziwa kumshicileli we-Ultimaker 3D we-3D (Italiya) kusetyenziswa indlela yokubeka ( FDM). iteknoloji isetyenziswa kwinkqubo yayo. Siprinte i-base plate kunye ne-main auxetic lattice structure kunye, kwaye siprinte umaleko ophezulu ngokwahlukeneyo. Oku kunceda ukuphepha naziphi na iingxaki ngexesha lenkqubo yokususa inkxaso ukuba yonke uyilo kufuneka iprintwe kanye. Emva koshicilelo lwe-3D, iindawo ezimbini ezihlukeneyo zidityaniswe kunye kusetyenziswa iglue enkulu. Siprinte la macandelo sisebenzisa i-polylactic acid (PLA) kwi-infill infill density (okt 100%) ukuthintela naziphi na iziphene zokushicilela zendawo.
Inkqubo ye-clamping yesiko ilinganisa iimeko ezifanayo zemida yenkxaso elula eyamkelwe kwimodeli yethu yohlalutyo. Oku kuthetha ukuba isixokelelwano sokubamba sithintela ibhodi ukuba ihambe ecaleni kwemiphetho yayo kwizalathiso zika-x kunye no-y, ivumela le mida ukuba ijikeleze ngokukhululekileyo malunga nee-axes zika-x kunye no-y. Oku kwenziwa ngokuqwalasela iifayili kunye ne-radius r = h / 2 kwimida emine yenkqubo yokubamba (umzobo 2). Le nkqubo ye-clamping iphinda iqinisekise ukuba umthwalo osetyenzisiweyo udluliselwa ngokupheleleyo kumatshini wokuvavanya kwiphaneli kwaye ulungelelaniswe nomgca ophakathi wepaneli (umzobo 2). Sasebenzisa i-multi-jet 3D iteknoloji yokushicilela (i-ObjetJ735 Connex3, i-Stratasys® Ltd., e-USA) kunye ne-resins zorhwebo eziqinileyo (ezifana ne-Vero series) ukuprinta inkqubo yokubamba.
Umzobo weSchematic we-3D eprintiweyo yesistim yokubamba isiko kunye nendibano yayo kunye nephaneli yesandwich eprintiweyo ye-3D ene-auxetic core.
Senza iimvavanyo ze-motion-controlled quasi-static compression test usebenzisa ibhentshi yokuvavanya i-mechanical (Lloyd LR, i-cell cell = 100 N) kwaye uqokelele amandla omatshini kunye nokufuduka kwinqanaba le-sampling ye-20 Hz.
Eli candelo libonisa uphononongo lwamanani lwesakhiwo sesandwich esicetywayo. Sicinga ukuba iileyile eziphezulu kunye nezantsi zenziwe nge-carbon epoxy resin, kwaye isakhiwo se-lattice se-core concave senziwe nge-polymer. Iimpawu zomatshini wezinto ezisetyenzisiweyo kolu phononongo ziboniswe kwiThebhile 2. Ukongezelela, umlinganiselo ongenakulinganiswa weziphumo zokufuduka kunye nemimandla yoxinzelelo iboniswe kwiThebhile 3.
Ukufuduka okuphezulu okuthe nkqo kwi-dimensionless ye-uniform elayishwe ngokukhululekileyo ipleyiti exhaswayo yathelekiswa neziphumo ezifunyenwe ngeendlela ezahlukeneyo (Itheyibhile 4). Kukho ukuvumelana okuhle phakathi kwethiyori ecetywayo, indlela yesiqalelo esinesiphelo kunye neziqinisekiso zovavanyo.
Siqhathanise i-vertical displacement ye-modified zigzag theory (RZT) kunye ne-3D elasticity theory (Pagano), i-first order shear deformation theory (FSDT), kunye neziphumo ze-FEM (jonga i-Fig. 3). Ithiyori yokuqala yokucheba, esekwe kwimizobo yokufuduswa kweepleyiti ezininzi ezishinyeneyo, yahluke kakhulu kwisisombululo esilastiki. Nangona kunjalo, ithiyori eguquliweyo ye-zigzag iqikelela iziphumo ezichanekileyo kakhulu. Ukongezelela, siphinde siqhathanise uxinzelelo lwe-shear oluphuma ngaphandle kwendiza kunye noxinzelelo oluqhelekileyo kwinqwelomoya yeethiyori ezahlukeneyo, phakathi kwazo i-theory ye-zigzag ifumene iziphumo ezichanekileyo kune-FSDT (umzobo 4).
Ukuthelekiswa koxinzelelo oluqhelekileyo oluthe nkqo olubalwa kusetyenziswa iithiyori ezahlukeneyo ku-y = b/2.
Utshintsho kuxinzelelo lokucheba (a) kunye noxinzelelo oluqhelekileyo (b) ngaphaya kobunzima bepaneli yesandwich, ibalwe kusetyenziswa ithiyori ezahlukeneyo.
Emva koko, sihlalutye impembelelo yeeparameters zejometri zeyunithi yeyunithi kunye ne-concave core kwiipropati ezipheleleyo zomatshini wepaneli yesandwich. I-angle yeyunithi yeseli yeyona parameter yejometri ebaluleke kakhulu ekuyilweni kwezakhiwo ze-lattice ezibuyelayo34,35,36. Ngoko ke, sibale impembelelo ye-angle yeyunithi yeeyunithi, kunye nobukhulu obungaphandle kwengundoqo, kwi-deflection epheleleyo yeplate (umzobo 5). Njengoko ubukhulu bomaleko ophakathi bukhula, ukuphambuka okuphezulu okungenamda kuyancipha. Amandla okugoba azalanayo ayanda kumaleko atyebileyo angundoqo kwaye xa \(\frac{{h}_{c}}{h}=1\) (okt, xa kukho umaleko omnye weconcave). Iiphaneli zeSandwich ezineyunithi yeseli ye-auxetic (okt \(\theta =70^\circ\)) zinezona ndawo zincinci zokufuduswa (Fig. 5). Oku kubonisa ukuba amandla okugoba ondoqo we-auxetic aphezulu kunalowo we-auxetic core yesiqhelo, kodwa ayisebenzi kakuhle kwaye inomlinganiselo wePoisson's positive.
Uphambuko oluqhelekileyo oluqhelekileyo lwentonga ye-concave ilettice eneengile zeeseli zeeyunithi ezahlukeneyo kunye nobukhulu obungaphandle kwenqwelomoya.
Ubuninzi be-core of the auxetic grating kunye ne-aspect ratio (okt \(\theta=70 ^\circ\)) ichaphazela ubuninzi bokufuduka kwe-sandwich plate (Umfanekiso 6). Kuyabonakala ukuba ukuphambuka okukhulu kweplate kwanda ngokunyuka kwe-h / l. Ukongeza, ukwandisa ubukhulu be-auxetic core kunciphisa i-porosity yesakhiwo se-concave, ngaloo ndlela kwandisa amandla okugoba kwesakhiwo.
Ukuphambuka okuphezulu kweepaneli zesandwich ezibangelwa izakhiwo ze-lattice kunye ne-auxetic core yobunzima obuhlukeneyo kunye nobude.
Uphononongo lwemimandla yoxinzelelo ngummandla onomdla onokuphononongwa ngokutshintsha iiparamitha zejometri zeyunithi yeyunithi yokufunda iindlela zokungaphumeleli (umzekelo, i-delamination) yezakhiwo ezininzi. Umlinganiselo wePoisson unempembelelo enkulu kwintsimi yoxinzelelo lwe-shear ngaphandle kwendiza kunoxinzelelo oluqhelekileyo (jonga umfanekiso we-7). Ukongeza, esi siphumo si-inhomogeneous kumacala ahlukeneyo ngenxa yeempawu ze-orthotropic zezinto zale gratings. Ezinye iiparameters zejometri, ezifana nobukhulu, ukuphakama, kunye nobude bezakhiwo ze-concave, zinempembelelo encinci kwintsimi yoxinzelelo, ngoko abazange bahlalutywe kolu cwaningo.
Ukutshintsha kumacandelo oxinzelelo lwe-chear kwiileya ezahlukeneyo zepaneli yesandwich ene-lattice filler ene-angles concavity ezahlukeneyo.
Apha, amandla okugoba epleyiti exhaswa ngokukhululekileyo ye-multilayer ene-concave lattice core iphandwa kusetyenziswa ithiyori ye-zigzag. Uqulunqo olucetywayo luthelekiswa nezinye iithiyori zeklasikhi, kubandakanywa ithiyori ye-elasticity ye-three-dimensional, i-first order order shear deformation theory, kunye ne-FEM. Sikwaqinisekisa indlela yethu ngokuthelekisa iziphumo zethu kunye neziphumo zovavanyo kulwakhiwo lwesandwich eprintiweyo ye-3D. Iziphumo zethu zibonisa ukuba ithiyori ye-zigzag iyakwazi ukuqikelela ukuguqulwa kwezakhiwo zesandwich ezinobunzima obuphakathi phantsi kwemithwalo egoba. Ukongezelela, impembelelo yeeparitha zejometri zesakhiwo se-concave lattice kwindlela yokuziphatha yokugoba yeepaneli zesandwich yahlalutywa. Iziphumo zibonisa ukuba njengoko inqanaba le-auxetic linyuka (oko kukuthi, θ <90), amandla okugoba ayanda. Ukongeza, ukwandisa umlinganiso we-aspect ratio kunye nokunciphisa ubukhulu be-core kuya kunciphisa ukugoba kwepaneli yesandwich. Ekugqibeleni, isiphumo somlinganiselo we-Poisson kuxinzelelo lwe-chear engaphandle kwenqwelomoya luyafundwa, kwaye kuqinisekisiwe ukuba umlinganiselo we-Poisson unempembelelo enkulu kuxinzelelo lokucheba oluveliswa bubunzima bepleyiti elaminethiweyo. Iifomyula ezicetywayo kunye nezigqibo zinokuvula indlela yoyilo kunye nokulungiswa kwezakhiwo ezininzi kunye ne-concave lattice fillers phantsi kweemeko ezinzima zokulayisha eziyimfuneko kuyilo lwezakhiwo ezithwala imithwalo kwi-aerospace kunye ne-biomedical technology.
Iiseti zedatha ezisetyenzisiweyo kunye/okanye ezihlalutyiweyo kuphononongo lwangoku ziyafumaneka kubabhali abachaphazelekayo ngesicelo esinengqiqo.
U-Aktai L., uJohnson AF kunye no-Kreplin B. Kh. Ukulinganisa kwamanani kwiimpawu zokutshatyalaliswa kwee-honeycomb cores. injineli. fractal. uboya. 75 (9), 2616-2630 (2008).
I-Gibson LJ kunye ne-Ashby MF Porous Solids: Isakhiwo kunye neePropati (iCambridge University Press, i-1999).
Ixesha lokuposa: Aug-12-2023