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Izakhiwo zamaphaneli e-Sandwich zisetshenziswa kabanzi ezimbonini eziningi ngenxa yezakhiwo zazo eziphezulu zemishini. I-interlayer yalezi zakhiwo iyisici esibaluleke kakhulu ekulawuleni nasekuthuthukiseni izakhiwo zabo zemishini ngaphansi kwezimo ezihlukahlukene zokulayisha. Izakhiwo ze-Concave lattice zingamakhandidethi avelele ukuze zisetshenziswe njengezihlanganisi kulezo zakhiwo zamasemishi ngezizathu ezimbalwa, okuwukuthi ukushuna ukunwebeka kwazo (isb., isilinganiso se-Poisson kanye namanani okuqina okunwebekayo) kanye ne-ductility (isb, ukunwebeka okuphezulu) ukuze kube lula. Izakhiwo zesilinganiso samandla nesisindo zitholwa ngokulungisa kuphela izakhi zejometri ezakha iyunithi yeseli. Lapha, siphenya impendulo eguquguqukayo yephaneli yesemishi ye-concave core enezingqimba ezi-3 sisebenzisa ukuhlaziya (okungukuthi, ithiyori ye-zigzag), yokubala (okungukuthi, into elinganiselwe) nokuhlola kokuhlola. Siphinde sahlaziya umphumela wamapharamitha ahlukahlukene wejiyomethri wesakhiwo selathisi ekhongome (isb. i-engeli, ukujiya, isilinganiso seyunithi yobude nesilinganiso sobude) ekuziphatheni okuphelele kwemishini kwesakhiwo sesemishi. Sithole ukuthi izakhiwo eziwumongo ezinokuziphatha kwe-auxetic (okungukuthi isilinganiso se-Poisson's negative) sibonisa amandla aphakeme aguquguqukayo kanye nengcindezi encane yokugunda ngaphandle kwendiza uma kuqhathaniswa nama-grating avamile. Esikutholile kungase kuvule indlela yokuthuthukiswa kwezakhiwo ezithuthukisiwe zezendlalelo eziningi ezinemiphetho ewumgogodla yezakhiwo ze-aerospace kanye nezinhlelo zokusebenza ze-biomedical.
Ngenxa yamandla azo aphezulu nesisindo esiphansi, izakhiwo zamasemishi zisetshenziswa kabanzi ezimbonini eziningi, okuhlanganisa ukuklanywa kwemishini yemishini neyezemidlalo, olwandle, i-aerospace, nobunjiniyela bezinto eziphilayo. Izakhiwo ze-Concave lattice ziyikhandidethi elilodwa elingase licatshangelwe njengezendlalelo eziwumgogodla kulezo zakhiwo eziyinhlanganisela ngenxa yamandla azo okumunca amandla aphezulu kanye nezakhiwo zesilinganiso samandla nesisindo esiphezulu1,2,3. Esikhathini esedlule, kuye kwenziwa imizamo emikhulu yokuklama izakhiwo zamasemishi ezingasindi ezinamalathisi ama-concave ukuze kuthuthukiswe izakhiwo zemishini. Izibonelo zemiklamo enjalo zihlanganisa imithwalo yengcindezi ephezulu emikhunjini yemikhumbi kanye nezinto zokudonsa ukushaqeka ezimotweni4,5. Isizathu sokuthi kungani ukwakhiwa kwe-lattice eyi-concave kudume kakhulu, kuyingqayizivele futhi ifanele ukwakhiwa kwephaneli yesemishi yikhono layo lokushuna ngokuzimela izakhiwo zayo ze-elastomechanical (isb. ukuqina okunwebekayo kanye nokuqhathanisa kwe-Poisson). Enye impahla ethokozisayo enjalo ukuziphatha kwe-auxetic (noma isilinganiso esibi se-Poisson), esisho ukunwetshwa kwe-lateral kwesakhiwo se-lattice lapho sinwetshwa ngobude. Lokhu kuziphatha okungajwayelekile kuhlobene nokuklanywa kwesakhiwo esincane samangqamuzana ayisisekelo ayisisekelo7,8,9.
Kusukela ocwaningweni lokuqala lukaLakes ekukhiqizeni amagwebu e-auxetic, kuye kwenziwa imizamo ebalulekile yokuthuthukisa izakhiwo ezimbotshana ezinenani elibi le-Poisson's ratio10,11. Kuphakanyiswe amajiyometri amaningana ukuze kuzuzwe le nhloso, njengamaseli eyunithi ajikelezayo, aqinile, aqinile, futhi aqinile,12 wonke abonisa ukuziphatha okuhle. Ukufika kobuchwepheshe bokukhiqiza okungeziwe (AM, okwaziwa nangokuthi ukuphrinta kwe-3D) kuphinde kwasiza ukuqaliswa kwalezi zakhiwo ze-2D noma ze-3D auxetic13.
Ukuziphatha kwe-auxetic kunikeza izakhiwo eziyingqayizivele zemishini. Isibonelo, i-Lakes ne-Elms14 ibonise ukuthi amagwebu e-auxetic anamandla esivuno esiphezulu, amandla omthelela aphezulu wokumunca amandla, nokuqina okuphansi kunamagwebu avamile. Ngokuphathelene nezakhiwo eziguquguqukayo zemishini yamagwebu e-auxetic, abonisa ukumelana okuphezulu ngaphansi kwemithwalo ephukile eguquguqukayo kanye nokuphakama okuphezulu ngaphansi kwe-tension ehlanzekile15. Ngaphezu kwalokho, ukusetshenziswa kwemicu ye-auxetic njengezinto zokuqinisa ezihlanganisiwe kuzothuthukisa izakhiwo zabo zemishini16 kanye nokumelana nomonakalo obangelwa i-fiber stretch17.
Ucwaningo luye lwabonisa nokuthi ukusebenzisa izakhiwo ze-concave auxetic njengengqikithi yezakhiwo ezihlanganisiwe ezigobile kungathuthukisa ukusebenza kwazo ngaphandle kwendiza, okuhlanganisa ukuqina okuguquguqukayo namandla18. Kusetshenziswa imodeli enezingqimba, kuphinde kwaphawulwa ukuthi i-auxetic core ingakhuphula amandla okuphuka kwamaphaneli ayinhlanganisela19. Izinhlanganisela ezinemicu ye-auxetic futhi zivimbela ukusakazeka kokuqhekeka uma kuqhathaniswa nemicu evamile20.
U-Zhang et al.21 wenze imodeli yokuziphatha kokungqubuzana kwezakhiwo zamaseli ezibuyayo. Bathole ukuthi ukumuncwa kwamandla kagesi namandla kungathuthukiswa ngokukhuphula i-engeli yeyunithi yeseli ye-auxetic, okuholela ekugayeni okunesilinganiso esingesihle kakhulu se-Poisson. Baphinde baphakamisa ukuthi amaphaneli amasemishi anjalo angasetshenziswa njengezakhiwo ezivikelayo emithwalweni yezinga eliphezulu lobunzima. I-Imbalzano et al.22 iphinde yabika ukuthi amashidi e-auxetic composite angahlakaza amandla amaningi (okungukuthi kabili) ngokusebenzisa ukuguqulwa kwepulasitiki futhi anganciphisa isivinini esiphezulu ohlangothini oluphambene ngo-70% uma kuqhathaniswa namashidi e-ply single.
Eminyakeni yamuva nje, ukunakwa okukhulu kuye kwakhokhwa ezifundweni zezinombolo nezokuhlola zezakhiwo zesemishi ezine-auxetic filler. Lezi zifundo zigqamisa izindlela zokuthuthukisa izakhiwo zemishini zalezi zakhiwo zamasemishi. Isibonelo, ukucabangela ungqimba oluqinile ngokwanele lwe-auxetic njengomongo wephaneli yesemishi kungaholela kumoduli esebenza kahle kakhulu ye-Young kunesendlalelo esiqine kakhulu23. Ngaphezu kwalokho, ukuziphatha okugobayo kwemishayo elaminethiwe 24 noma auxetic core tubes 25 kungathuthukiswa nge-algorithm yokwenza kahle. Kukhona ezinye izifundo ekuhlolweni kwemishini kwezakhiwo zesemishi eziwumongo ezinwebekayo ngaphansi kwemithwalo enzima kakhulu. Isibonelo, ukuhlolwa kokucindezelwa kwezinhlanganisela zikakhonkolo ezinama-auxetic aggregates, amaphaneli esisemishi ngaphansi kwemithwalo eqhumayo27, ukuhlolwa okugobayo28 kanye nokuhlolwa komthelela wesivinini esiphansi29, kanye nokuhlaziywa kokugoba okungewona umugqa kwamaphaneli amasemishi anezilinganiso ze-auxetic ezihlukanisiwe zokusebenza30.
Ngenxa yokuthi ukulingisa kwekhompyutha nokuhlolwa kokuhlola kwemiklamo enjalo kuvame kudla isikhathi futhi kubiza, kunesidingo sokuthuthukisa izindlela zethiyori ezingahlinzeka ngolwazi oludingekayo ukuze kuklanywe izakhiwo eziyinhloko ze-multilayer auxetic ngaphansi kwezimo zokulayisha ngokunganaki. isikhathi esifanele. Nokho, izindlela zokuhlaziya zesimanje zinemingcele eminingi. Ikakhulukazi, le mibono ayinembile ngokwanele ukubikezela ukuziphatha kwezinto eziyinhlanganisela ewugqinsi nokuhlaziya izinhlanganisela ezakhiwe ngezinto ezimbalwa ezinezakhiwo ezinwebekayo ezihluke kakhulu.
Njengoba lawa mamodeli okuhlaziya ancike emithwalweni esetshenzisiwe kanye nezimo zomngcele, lapha sizogxila ekuziphatheni okuguquguqukayo kwamaphaneli e-auxetic core sandwich. Ithiyori yesendlalelo esilinganayo esetshenziselwa ukuhlaziya okunjalo ayikwazi ukubikezela ngokunembile ukucindezelwa kwe-shear ne-axial kuma-laminates ane-homogeneous kakhulu kuzinhlanganisela zamasemishi ubukhulu obumaphakathi. Ngaphezu kwalokho, kwezinye izinkolelo-mbono (isibonelo, ku-theory enezingqimba), inani lezinto eziguquguqukayo ze-kinematic (isibonelo, ukufuduka, isivinini, njll.) lincike kakhulu enanini lezendlalelo. Lokhu kusho ukuthi inkambu yokunyakaza kwesendlalelo ngasinye ingachazwa ngokuzimela, kuyilapho yanelisa izithiyo ezithile zokuqhubeka ngokomzimba. Ngakho-ke, lokhu kuholela ekucabangeni inani elikhulu lezinto eziguquguqukayo kumodeli, okwenza le ndlela ibize kakhulu. Ukuze sinqobe le mikhawulo, siphakamisa indlela esekelwe kumfundiso ye-zigzag, isigaba esingaphansi esithile sethiyori yamaleveli amaningi. Ithiyori ihlinzeka ngokuqhubekayo kwengcindezi ye-shear kulo lonke ugqinsi lwe-laminate, ithatha iphethini ye-zigzag yokufuduka kwendiza. Ngakho-ke, i-theory ye-zigzag inikeza inani elifanayo lokuguquguquka kwe-kinematic kungakhathaliseki ukuthi inani lezingqimba ku-laminate.
Ukuze sibonise amandla endlela yethu ekubikezeleni ukuziphatha kwamaphaneli amasemishi anama-concave cores ngaphansi kwemithwalo egotshwayo, siqhathanise imiphumela yethu nethiyori yakudala (okungukuthi indlela yethu yokwenza amamodeli wekhompyutha (okungukuthi, izakhi ezilinganiselwe) kanye nedatha yokuhlola (okungukuthi ukugoba amaphuzu amathathu Amaphaneli amasemishi aphrintiwe e-3D).Kuze kube sekugcineni, siqale sathola ubudlelwano bokufuduka obususelwe kumbono wamazombezombe, bese sathola izibalo eziyisisekelo sisebenzisa isimiso sika-Hamilton futhi sazixazulula sisebenzisa indlela ye-Galerkin.Imiphumela etholiwe iyithuluzi elinamandla lokuklama okuhambisanayo. amapharamitha wejometri wamaphaneli wesangweji anama-auxetic fillers, asiza ukusesha izakhiwo ezinezakhiwo ezithuthukisiwe zemishini.
Cabanga ngephaneli lesangweji lezendlalelo ezintathu (Fig. 1). Amapharamitha wedizayini yeJiyomethri: ungqimba olungaphezulu \({h}_{t}\), ungqimba oluphakathi \({h}_{c}\) nongqimba olungezansi \({h}_{ b }\) ukujiya. Sicabanga ukuthi ingqikithi yesakhiwo iqukethe isakhiwo se-lattice esinezimbotshana. Isakhiwo siqukethe amaseli ayisisekelo ahlelwe eduze kwelinye ngendlela ehlelekile. Ngokushintsha imingcele yejometri yesakhiwo se-concave, kungenzeka ukuguqula izakhiwo zayo zemishini (okungukuthi, amanani we-Poisson's ratio kanye nokuqina okunwebekayo). Imingcele yejiyomethri yeseli eyisisekelo iboniswa ku-Fig. 1 kufaka phakathi i-engeli (θ), ubude (h), ubude (L) nogqinsi lwekholomu (t).
Ithiyori ye-zigzag inikeza izibikezelo ezinembe kakhulu zengcindezi nokuziphatha kokucindezeleka kwezakhiwo eziyinhlanganisela ezinezingqimba zogqinsi olumaphakathi. Ukugudluzwa kwesakhiwo kumbono wamazombezombe kuqukethe izingxenye ezimbili. Ingxenye yokuqala ibonisa ukuziphatha kwephaneli ye-sandwich lilonke, kuyilapho ingxenye yesibili ibheka ukuziphatha phakathi kwezingqimba ukuze kuqinisekiswe ukuqhubeka kokucindezeleka kwe-shear (noma lokho okubizwa ngokuthi umsebenzi we-zigzag). Ngaphezu kwalokho, isici se-zigzag siyanyamalala endaweni yangaphandle ye-laminate, hhayi ngaphakathi kwalolu ungqimba. Ngakho-ke, umsebenzi wamazombezombe uqinisekisa ukuthi isendlalelo ngasinye sinomthelela ekuwohlokeni okuphelele kwesigaba esiphambanayo. Lo mehluko obalulekile uhlinzeka ngokusabalaliswa okungokoqobo okungokoqobo komsebenzi wamazombezombe uma kuqhathaniswa neminye imisebenzi yamazombezombe. Imodeli yamanje eguquliwe ye-zigzag ayinikezi ukuqhubeka kwengcindezi ye-shear eduze nongqimba olumaphakathi. Ngakho-ke, inkambu yokuthutha esekelwe kumbono we-zigzag ingabhalwa kanje31.
ku-equation. (1), u-k=b, u-c kanye no-t bamele izendlalelo ezingezansi, ezimaphakathi nezingaphezulu, ngokulandelana. Inkambu yokugudluka yendiza emaphakathi eduze kwe-eksisi yeCartesian (x, y, z) ingu-(u, v, w), futhi ukuphenduka okugoba endizeni mayelana ne-eksisi (x, y) ngu-\({\uptheta} _ {x}\) kanye \ ({\ uptheta}_{y}\). I-\({\psi}_{x}\) kanye \({\psi}_{y}\) yinani lendawo lokuzungezisa ama-zigzag, kanye \({\phi}_{x}^{k}\ kwesokunxele ( z \kwesokudla)\) kanye nokuthi \({\phi}_{y}^{k}\left(z\right)\) kuyimisebenzi yamazombezombe.
I-amplitude ye-zigzag ingumsebenzi we-vector wempendulo yangempela yepuleti kumthwalo osetshenzisiwe. Zihlinzeka ngokukala okufanele komsebenzi wamazombezombe, ngaleyo ndlela zilawule wonke umnikelo we-zigzag ekususweni endizeni. I-Shear strain yonkana ukujiya kwepuleti iqukethe izingxenye ezimbili. Ingxenye yokuqala i-engeli yokugunda, iyunifomu yonkana ukujiya kwe-laminate, kanti ingxenye yesibili iwumsebenzi ongaguquki, umfaniswano phakathi kogqinsi longqimba ngalunye. Ngokwale misebenzi engaguquki, umsebenzi wamazombezombe wesendlalelo ngasinye ungabhalwa kanje:
ku-equation. (2), \({c}_{11}^{k}\) kanye \({c}_{22}^{k}\) yizingqimba ezinwebekayo zesendlalelo ngasinye, futhi u-h uyingqikithi yogqinsi idiski. Ngaphezu kwalokho, \({G}_{x}\) kanye \({G}_{y}\) amakhoefiyenti okuqina we-shear anesisindo, avezwa njengokuthi 31:
Imisebenzi emibili ye-amplitude ye-zigzag (I-Equation (3)) kanye neziguquguquki ze-kinematic ezinhlanu ezisele (I-Equation (2)) yethiyori yokuqala ye-shear deformation yakha isethi yama-kinematics ayisikhombisa ahlotshaniswa nalokhu okuguquguqukayo kwe-zigzag plate theory variable. Ngokucabangela ukuncika komugqa wokuguquguquka futhi kucatshangelwa ithiyori ye-zigzag, inkambu yokuguquguquka ohlelweni lwe-Cartesian coordinate ingatholakala njenge:
lapho \({\varepsilon}_{yy}\) kanye \({\varepsilon}_{xx}\) kuwukuwohloka okuvamile, kanye \({\gamma}_{yz},{\gamma}_{xz} \ ) kanye ne-\({\gamma}_{xy}\) kungukonakala kwe-shear.
Kusetshenziswa umthetho ka-Hooke futhi kucatshangelwa ithiyori e-zigzag, ubudlelwano phakathi kwengcindezi kanye nobunzima bepuleti le-orthotropic elinesakhiwo se-concave lattice bungatholakala kuzibalo (1). (5)32 lapho \({c}_{ij}\) okuyi-elastic constant ye-stress-strain matrix.
lapho \({G}_{ij}^{k}\), \({E}_{ij}^{k}\) kanye \({v}_{ij}^{k}\) esikwa khona amandla yimodulus ezinhlangothini ezahlukene, i-Young's modulus kanye ne-Poisson's ratio. Lawa ma-coefficient alingana kuzo zonke izinkomba zesendlalelo se-isotopic. Ngaphezu kwalokho, ku-nuclei ebuyayo ye-lattice, njengoba kuboniswe ku-Fig. 1, lezi zakhiwo zingabhalwa kabusha njengo-33.
Ukusetshenziswa komgomo ka-Hamilton ezilinganisweni zokunyakaza kwepuleti lezendlalelo eziningi elinomgogodla we-lattice concave kunikeza izibalo eziyisisekelo zomklamo. Isimiso sikaHamilton singabhalwa kanje:
Phakathi kwazo, u-δ umele isisebenzisi esishintshashintshayo, u-U umele amandla angaba namandla, futhi u-W umele umsebenzi owenziwe amandla angaphandle. Isamba samandla anamandla atholakala kusetshenziswa isibalo. (9), lapho u-A eyisifunda sendiza emaphakathi.
Ngokucabangela ukusetshenziswa okufanayo komthwalo (p) ohlangothini luka-z, umsebenzi wamandla angaphandle ungatholakala kufomula elandelayo:
Kushintshwa isibalo Izibalo (4) kanye (5) (9) bese kungena esikhundleni sezibalo. (9) kanye no-(10) (8) futhi ihlanganisa ngaphezu kogqinsi lwepuleti, isibalo: (8) singabhalwa kabusha ngokuthi:
Inkomba \(\phi\) imele umsebenzi wamazombezombe, \({N}_{ij}\) kanye nokuthi \({Q}_{iz}\) kungamandla okungena nokuphuma endizeni, \({M} _{ij }\) imele isikhathi sokugoba, futhi ifomula yokubala imi kanje:
Ukusebenzisa ukuhlanganisa ngezingxenye zesibalo. Ukufaka esikhundleni sefomula (12) kanye nokubala i-coefficient of variation, i-equation echazayo yephaneli yesemishi ingatholwa ngendlela yefomula (12). (13).
Izibalo zokulawula okuhlukile zamapuleti anezendlalelo ezintathu ezisekelwa ngokukhululekile zixazululwa ngendlela ye-Galerkin. Ngaphansi kokucatshangwa kwezimo ze-quasi-static, umsebenzi ongaziwa ubhekwa njengesibalo: (14).
\({u}_{m,n}\), \({v}_{m,n}\), \({w}_{m,n}\),\({{\ uptheta}_) {\mathrm {x}}}_{\mathrm {m} \text{,n}}\),\({{\ uptheta }_{\mathrm {y}}}_{\mathrm {m} \umbhalo {,n}}\), \({{\uppsi}_{\mathrm{x}}}_{\mathrm{m}\text{,n}}\) kanye \({{\uppsi}_{ \mathrm{y}}_{\mathrm{m}\text{,n}}\) yizinto ezingaguquki ezingaziwa ezingatholwa ngokunciphisa iphutha. \(\ overline{\ overline{u}} \kwesokunxele({x{\text{,y}}} \kwesokudla)\), \(\ overline{\ overline{v}} \left({x{\text {,y}}} \kwesokudla)\), \(\umugqa ngaphezulu{\ ngaphezulu komugqa{w}} \kwesokunxele( {x{\umbhalo{,y}}} \kwesokudla)\), \(\ ngaphezulu komugqa{\ ngaphezulu komugqa {{{\ uptheta}_{x}}}} \kwesokunxele( {x{\ text{,y}}} \kwesokudla)\), \(\ overline{\ overline{{{\ uptheta}_{y} }}} \kwesokunxele( {x{\text{,y}}} \kwesokudla)\), \(\ overline{\ overline{{\psi_{x}}}} \left( {x{\text{, y}}} \kwesokudla)\) kanye nokuthi \(\okubekwe ngaphezulu{\ ngaphezulu kwe-line{{ \psi_{y} }}}} \kwesokunxele( {x{\umbhalo{,y}}} \kwesokudla)\) kuyimisebenzi yokuhlola, okumele kwenelise ubuncane bemibandela yemingcele edingekayo. Ezimweni zomngcele ezisekelwe nje, umsebenzi wokuhlola ungabalwa kabusha ngokuthi:
Ukushintshwa kwezibalo kunikeza izibalo ze-algebraic. (14) ezilinganisweni ezilawulayo, ezingaholela ekutholeni ama-coefficient angaziwa esibalweni (14). (14).
Sisebenzisa i-finite element modelling (FEM) ukuze silingise ikhompuyutha ukugoba kwephaneli yesemishi elisekelwa ngokukhululekile ngesakhiwo se-concave lattice njengomongo. Ukuhlaziya kwenziwe ngekhodi yento elinganiselwe yezentengiso (isibonelo, inguqulo ye-Abaqus 6.12.1). Izingxenye eziqinile ze-3D hexahedral (C3D8R) ezinokuhlanganisa okwenziwe lula zasetshenziswa ukuze kwenziwe imodeli yezendlalelo ezingaphezulu nezingaphansi, futhi izakhi ze-tetrahedral ezinomugqa (C3D4) zisetshenziswe ukwenza imodeli yesakhiwo se-lattice esimaphakathi (i-concave). Senze ukuhlaziya ukuzwela kwe-mesh ukuze sihlole ukuhlangana kwe-mesh futhi saphetha ngokuthi imiphumela yokugudluzwa ihlangane ngosayizi wesici omncane kakhulu phakathi kwezendlalelo ezintathu. Ipuleti lesangweji lilayishwa kusetshenziswa umsebenzi womthwalo we-sinusoidal, kucatshangelwa izimo zemingcele ezisekelwa ngokukhululekile emaphethelweni amane. Umugqa wokuziphatha okunwebekayo komugqa uthathwa njengemodeli yezinto ezibonakalayo eyabelwe zonke izendlalelo. Akukho ukuxhumana okuqondile phakathi kwezingqimba, zixhumene.
Sisebenzise amasu okuphrinta e-3D ukuze sakhe i-prototype yethu (okungukuthi iphaneli yesemishi ye-auxetic core ephrintiwe kathathu) kanye nokusetha okuhambisanayo kokuhlola ukuze kusetshenziswe izimo zokugoba ezifanayo (ukulayisha okulinganayo p eduze kwesikhombisi-ndlela esingu-z) kanye nezimo zomngcele (okungukuthi. kusekelwa nje). kucatshangwa endleleni yethu yokuhlaziya (Fig. 1).
Iphaneli lesemishi eliphrintwe kuphrinta ye-3D linezikhumba ezimbili (ezingenhla nezingaphansi) kanye ne-concave lattice core, ubukhulu bazo obuvezwe kuThebula 1, futhi lakhiwe ngephrinta ye-Ultimaker 3 3D (Italy) kusetshenziswa indlela yokubeka ( FDM). ubuchwepheshe busetshenziswa enqubweni yabo. I-3D saphrinta i-base plate kanye ne-main auxetic lattice structure ndawonye, futhi saphrinta isendlalelo esiphezulu ngokuhlukana. Lokhu kusiza ukugwema noma yiziphi izinkinga phakathi nenqubo yokususa ukusekela uma yonke idizayini kufanele iphrintwe ngesikhathi esisodwa. Ngemuva kokuphrinta kwe-3D, izingxenye ezimbili ezihlukene zihlanganiswa ndawonye kusetshenziswa i-superglue. Siphrinte lezi zingxenye sisebenzisa i-polylactic acid (i-PLA) ekumineni okuphezulu kakhulu kokungagcwaliswa (okungukuthi 100%) ukuze sinqande noma yikuphi ukonakala kwendawo yokuphrinta.
Isistimu yokubopha ngokwezifiso ilingisa izimo zomngcele wosekelo ezifanayo ezitholwa kumodeli yethu yokuhlaziya. Lokhu kusho ukuthi isistimu yokubamba ivimbela ibhodi ukuthi lingahambi emaphethelweni alo kuzikhombisi-ndlela zika-x kanye no-y, okuvumela le miphetho ukuthi ijikeleze ngokukhululekile kuma-ax kanye no-y. Lokhu kwenziwa ngokucabangela izibopho ezine-radius r = h / 2 emaphethelweni amane esistimu yokubamba (Fig. 2). Lolu hlelo lwe-clamping luphinde luqinisekise ukuthi umthwalo osetshenzisiwe udluliselwa ngokugcwele kusuka emshinini wokuhlola kuya kuphaneli futhi uhambisane nomugqa ophakathi wephaneli (umkhiwane 2). Sisebenzise ubuchwepheshe bokuphrinta be-3D obuningi bejethi (ObjetJ735 Connex3, Stratasys® Ltd., USA) kanye nezinsalela zokuhweba eziqinile (ezifana nochungechunge lwe-Vero) ukuze siphrinte isistimu yokubamba.
Umdwebo oyisikimu wesistimu yokubamba ngokwezifiso ephrintiwe ye-3D kanye nokuhlanganiswa kwayo ngephaneli yesemishi eliphrintiwe le-3D elinomgogodla we-auxetic.
Senza ukuhlola kokuminyanisa okulawulwa ukunyakaza kwe-quasi-static sisebenzisa ibhentshi lokuhlola lomshini (Lloyd LR, load cell = 100 N) futhi siqoqa amandla omshini nokugudluzwa ngesilinganiso samasampula esingu-20 Hz.
Lesi sigaba sethula ucwaningo lwezinombolo lwesakhiwo sesemishi esihlongozwayo. Sicabanga ukuthi izendlalelo ezingaphezulu neziphansi zenziwe nge-carbon epoxy resin, futhi isakhiwo se-lattice se-concave core senziwa nge-polymer. Izici zomshini zezinto ezisetshenziswe kulolu cwaningo ziboniswa kuThebula 2. Ngaphezu kwalokho, izilinganiso ezingenasici zemiphumela yokufuduka nezinkambu zokucindezeleka ziboniswa kuThebula lesi-3.
Ukukhishwa okuphezulu okume mpo kwe-dimensionless kwepuleti elisekelwa ngokukhululekile elilayishwe ngokukhululekile kwaqhathaniswa nemiphumela etholwe ngezindlela ezihlukene (Ithebula 4). Kukhona ukuvumelana okuhle phakathi kwethiyori ehlongozwayo, indlela yesici esilinganiselwe nokuqinisekisa kokuhlola.
Siqhathanise ukugudluka okuqondile kwe-modified zigzag theory (RZT) ne-3D elasticity theory (Pagano), i-first order shear deformation theory (FSDT), kanye nemiphumela ye-FEM (bona i-Fig. 3). Ithiyori ye-shear ye-oda lokuqala, esekelwe emidwebeni yokugudluka yamapuleti aminyene aminyene, ihluke kakhulu kusixazululo esinwebekayo. Nokho, ithiyori eguquliwe ye-zigzag ibikezela imiphumela enembe kakhulu. Ukwengeza, siphinde siqhathanise ukucindezeleka kwe-shear ngaphandle kwendiza kanye nokucindezeleka okuvamile kwendiza yemibono ehlukahlukene, phakathi kwayo inkolelo ye-zigzag ithole imiphumela enembe kakhulu kune-FSDT (Fig. 4).
Ukuqhathaniswa kohlobo olujwayelekile olume mpo olubalwa kusetshenziswa amathiyori ahlukene kokuthi y = b/2.
Ushintsho ekucindezelweni kwe-shear (a) kanye nengcindezi evamile (b) kulo lonke ugqinsi lwephaneli yesemishi, olubalwa kusetshenziswa amathiyori ahlukahlukene.
Okulandelayo, sihlaziye umthelela wamapharamitha wejiyomethri weyunithi yeseli nge-concave core kuzo zonke izakhiwo zemishini zephaneli yesemishi. I-engeli yeyunithi yeseli iyipharamitha yejiyomethri ebaluleke kakhulu ekwakhiweni kwezakhiwo ze-lattice eziphindayo34,35,36. Ngakho-ke, sibale ithonya le-angle yeyunithi yeseli, kanye nobukhulu obungaphandle komgogodla, ekuphambukeni okuphelele kwepuleti (Fig. 5). Njengoba ukushuba kongqimba olumaphakathi kukhula, ukuchezuka okungena-dimensionless okuphezulu kuyehla. Amandla okugoba ahlobene ayakhula ezingqimbeni eziwumgogodla ezijiyile nalapho \(\frac{{h}_{c}}{h}=1\) (okungukuthi, uma kunongqimba olulodwa lwe-concave). Amaphaneli e-Sandwich ane-auxetic unit cell (okungukuthi \(\theta =70^\circ\)) anokususwa okuncane kakhulu (Fig. 5). Lokhu kukhombisa ukuthi amandla okugoba we-auxetic core angaphezulu kwawe-auxetic core evamile, kodwa awasebenzi kahle futhi anesilinganiso esihle se-Poisson.
Ukuchezuka okuphezulu okujwayelekile kwe-concave lattice rod enama-engeli amaseli eyunithi ahlukene kanye nogqinsi lwangaphandle kwendiza.
Ugqinsi lwe-core of the auxetic grating kanye ne-aspect ratio (okungukuthi \(\theta=70^\circ\)) kuthinta ukugudluzwa okukhulu kwepuleti lesemishi (Umfanekiso 6). Kungabonakala ukuthi ukuphambuka okuphezulu kwepuleti kukhuphuka ngokukhuphuka kwe-h / l. Ngaphezu kwalokho, ukwandisa ukushuba kwe-auxic core kunciphisa i-porosity yesakhiwo se-concave, ngaleyo ndlela kwandise amandla okugoba esakhiwo.
Ukuchezuka okukhulu kwamaphaneli amasemishi okubangelwa izakhiwo ze-lattice ezinomongo we-auxetic wobukhulu nobude obuhlukahlukene.
Ucwaningo lwezinkambu zokucindezeleka luyindawo ethakazelisayo engahlolwa ngokushintsha amapharamitha wejometri weyunithi yeseli ukuze kufundwe izindlela zokuhluleka (isb, i-delamination) yezakhiwo ze-multilayer. Isilinganiso sikaPoisson sinomthelela omkhulu emkhakheni wokucindezela kwe-shear ngaphandle kwendiza kunokucindezeleka okuvamile (bheka umdwebo 7). Ngaphezu kwalokho, lo mphumela u-inhomogeneous ngezindlela ezahlukene ngenxa yezakhiwo ze-orthotropic zezinto zalawa ma-gratings. Eminye imingcele yejometri, njengobukhulu, ukuphakama, nobude bezakhiwo ze-concave, yayinomthelela omncane emkhakheni wokucindezeleka, ngakho ayizange ihlaziywe kulolu cwaningo.
Shintsha izingxenye zengcindezi ye-shear ezendlalelo ezahlukene zephaneli yesemishi elinesigcwalisi se-lattice esinama-engeli ahlukene we-concavity.
Lapha, amandla okugoba epuleti le-multilayer elisekelwa ngokukhululekile elinomgogodla we-lattice ye-concave ayaphenywa kusetshenziswa ithiyori ye-zigzag. Ukwakhiwa okuhlongozwayo kuqhathaniswa neminye imibono yakudala, ehlanganisa ithiyori yokunwebeka kwezinhlangothi ezintathu, ithiyori yokuguga ye-shear ye-oda lokuqala, kanye ne-FEM. Siphinde siqinisekise indlela yethu ngokuqhathanisa imiphumela yethu nemiphumela yokuhlola kuzakhiwo zamasemishi eziphrintiwe ze-3D. Imiphumela yethu ibonisa ukuthi ithiyori ye-zigzag iyakwazi ukubikezela ukuwohloka kwezakhiwo zesemishi ezinogqinsi olumaphakathi ngaphansi kwemithwalo egotshwayo. Ngaphezu kwalokho, kwahlaziywa umthelela wemingcele yejiyomethri yesakhiwo se-concave lattice ekuziphatheni kokugoba kwamaphaneli amasemishi. Imiphumela ibonisa ukuthi njengoba izinga le-auxetic likhuphuka (okungukuthi, θ <90), amandla okugoba ayanda. Ngaphezu kwalokho, ukwandisa i-aspect ratio kanye nokunciphisa ukujiya komgogodla kuzonciphisa amandla okugoba wephaneli yesangweji. Ekugcineni, umphumela wesilinganiso se-Poisson ekucindezelweni kwe-shear ngaphandle kwendiza kuyafundwa, futhi kuyaqinisekiswa ukuthi isilinganiso sikaPoisson sinethonya elikhulu ekucindezelweni kwe-shear okukhiqizwa ukushuba kwepuleti elaminate. Amafomula ahlongozwayo neziphetho zingavula indlela eya ekwakhiweni nasekusetshenzisweni kahle kwezakhiwo zezendlalelo eziningi ezinezigcwali ze-concave lattice ngaphansi kwezimo eziyinkimbinkimbi zokulayisha ezidingekayo ukuze kuklanywe izakhiwo ezithwala imithwalo ku-aerospace kanye nobuchwepheshe be-biomedical.
Amasethi edatha asetshenzisiwe kanye/noma ahlaziywa ocwaningweni lwamanje ayatholakala kubabhali abafanele uma kunesicelo esifanele.
U-Aktai L., Johnson AF kanye no-Kreplin B. Kh. Ukulingiswa kwezinombolo kwezici zokucekelwa phansi kwezinyosi zezinyosi. unjiniyela. i-fractal. uboya. 75(9), 2616–2630 (2008).
I-Gibson LJ kanye ne-Ashby MF Porous Solids: Isakhiwo Nezakhiwo (Cambridge University Press, 1999).
Isikhathi sokuthumela: Aug-12-2023