Kea leboha ha u etetse Nature.com. U sebelisa mofuta oa sebali o nang le tšehetso e fokolang ea CSS. Bakeng sa boiphihlelo bo botle ka ho fetesisa, re khothaletsa hore o sebelise sebatli se ntlafalitsoeng (kapa o tima Compatibility Mode ho Internet Explorer). Khabareng, ho netefatsa ts'ehetso e tsoelang pele, re bonts'a sebaka sa marang-rang se se nang mekhoa le JavaScript.
Mehaho ea liphanele tsa sandwich li sebelisoa haholo liindastering tse ngata ka lebaka la thepa ea tsona e phahameng ea mochini. The interlayer ea mehaho ena ke ntlha ea bohlokoa haholo ho laola le ho ntlafatsa thepa ea bona ea mechine tlas'a maemo a sa tšoaneng a ho laela. Mehaho ea "concave lattice" ke likhetho tse hlahelletseng bakeng sa ho sebelisoa e le li-interlayers meahong e joalo ea sandwich ka mabaka a 'maloa, e leng ho fetola elasticity ea tsona (mohlala, karo-karolelano ea Poisson le boleng ba ho tiea ha elastic) le ductility (mohlala, elasticity e phahameng) bakeng sa bonolo. Maemo a karo-karolelano ea matla ho boima a finyelloa ka ho lokisa feela likarolo tsa geometri tse etsang sele ea unit. Mona, re batlisisa karabelo e feto-fetohang ea phanele ea sandwich ea 3-layer concave core ho sebelisa analytical (ke hore, theory zigzag), computational (ke hore, finite element) le liteko tsa liteko. Re boetse re hlahlobile sephetho sa liparamente tse fapaneng tsa geometric tsa sebopeho sa "concave lattice" (mohlala, sekhutlo, botenya, tekanyo ea selelele ea yuniti ho isa bophahamong) ho boits'oaro bo akaretsang ba sebopeho sa sandwich. Re fumane hore meaho ea mantlha e nang le boits'oaro bo botle (ke hore, karo-karolelano e mpe ea Poisson) e bonts'a matla a ho feto-fetoha a phahameng le khatello e fokolang ea ho kuta ka ntle ho sefofane ha e bapisoa le gratings e tloaelehileng. Liphuputso tsa rona li ka bula tsela bakeng sa nts'etsopele ea meaho ea meaho e mengata e tsoetseng pele e nang le meaho ea mantlha bakeng sa lisebelisoa tsa sefofane le biomedical.
Ka lebaka la matla a bona a phahameng le boima ba 'mele bo tlase, meaho ea sandwich e sebelisoa haholo liindastering tse ngata, ho kenyeletsoa moralo oa lisebelisoa tsa mochini le lipapali, marine, aerospace, le boenjiniere ba biomedical. Mehaho ea "concave lattice" ke mokhethoa a le mong ea ka nkoang e le likarolo tsa mantlha ka har'a meaho e joalo e nang le likarolo tse ngata ka lebaka la matla a holimo a ho monya matla le thepa e phahameng ea boima ba 'mele1,2,3. Nakong e fetileng, ho entsoe matsapa a maholo a ho rala meaho ea sandwich e bobebe e nang le li-concave lattices ho ntlafatsa lisebelisoa tsa mochini. Mehlala ea meralo e joalo e kenyelletsa meroalo ea khatello e phahameng ka har'a likepe tsa likepe le lintho tse kenang ka har'a likoloi4,5. Lebaka leo ka lona sebopeho sa "concave lattice" se tumme haholo, se ikhethile ebile se loketse kaho ea phanele ea sandwich ke bokhoni ba sona ba ho iketsetsa thepa ea eona ea elastomechanical (mohlala, ho tiea ha elastic le papiso ea Poisson). E 'ngoe ea thepa e joalo e khahlang ke boits'oaro ba auxetic (kapa karo-karolelano e mpe ea Poisson), e bolelang katoloso ea lateral ea sebopeho sa lattice ha se otlolloa ka bolelele. Boitšoaro bona bo sa tloaelehang bo amana le moralo oa microstructural oa lisele tsa eona tsa mantlha7,8,9.
Ho tloha lipatlisisong tsa pele tsa Lakes mabapi le tlhahiso ea foams ea auxetic, ho entsoe boiteko bo boholo ho nts'etsapele meaho e nang le masoba ka karolelano e mpe ea Poisson10,11. Ho 'nile ha etsoa tlhahiso ea li-geometries tse' maloa ho finyella sepheo sena, tse kang li-unit tsa li-unit tsa chiral, tse thata-thata, le tse thata, tse 12 kaofela li bonts'a boitšoaro bo sa tloaelehang. Ho fihla ha litheknoloji tsa tlhahiso ea li-additive (AM, eo hape e tsejoang e le 3D printing) thekenoloji e boetse e nolofalitse ts'ebetsong ea 2D kapa 3D auxetic structures13.
Boitšoaro ba auxetic bo fana ka thepa e ikhethang ea mochini. Mohlala, Lakes le Elms14 li bonts'itse hore li-auxetic foams li na le matla a ho kotuloa a phahameng, matla a ho monya matla a phahameng, le ho satalla ho tlase ho feta makoko a tloaelehileng. Mabapi le lisebelisoa tse matla tsa mochini oa li-auxetic foams, li bonts'a khanyetso e phahameng tlas'a meroalo e matla ea ho robeha le bolelele bo phahameng tlas'a tsitsipano e hloekileng15. Ho phaella moo, tšebeliso ea likhoele tsa auxetic e le lisebelisoa tse matlafatsang ka li-composite li tla ntlafatsa thepa ea bona ea mechine16 le ho hanyetsa tšenyo e bakoang ke fiber stretch17.
Patlisiso e boetse e bonts'itse hore ho sebelisa meaho ea concave auxetic joalo ka mantlha ea meaho e kobehileng e ka ntlafatsa ts'ebetso ea bona e kantle ho sefofane, ho kenyeletsoa ho satalla ha flexural le matla18. Ho sebelisoa mohlala o nang le lesela, ho boetse ho hlokometsoe hore mokokotlo oa auxetic o ka eketsa matla a ho robeha ha liphanele tse kopantsoeng19. Li-composites tse nang le li-auxetic fibers li boetse li thibela ho ata ha crack ha ho bapisoa le likhoele tse tloaelehileng20.
Zhang et al.21 ba ile ba etsa mohlala oa ts'ebetso ea ho thulana ha lisele tse khutlang. Ba fumane hore ho kenngoa ha motlakase le matla ho ka ntlafatsoa ka ho eketsa angle ea sele ea auxetic unit cell, e leng se bakang grating e nang le karo-karolelano e mpe ea Poisson. Ba boetse ba khothalelitse hore liphanele tse joalo tsa "auxetic sandwich" li ka sebelisoa e le meaho e sirelletsang khahlano le meroalo e phahameng ea khatello. Imbalzano et al.22 e boetse e tlaleha hore lipampiri tse nang le li-auxetic composite li ka senya matla a mangata (ke hore ka makhetlo a mabeli) ka deformation ea polasetiki 'me li ka fokotsa lebelo le holimo ka lehlakoreng le ka morao ka 70% ha li bapisoa le maqephe a le mong.
Lilemong tsa morao tjena, ho lebisitsoe tlhokomelo e ngata lithutong tsa lipalo le tsa liteko tsa meaho ea sandwich e nang le li-auxetic filler. Liphuputso tsena li totobatsa mekhoa ea ho ntlafatsa thepa ea mechine ea li-sandwich tsena. Ka mohlala, ho nahana ka lera le lekaneng la "auxetic layer" e le motheo oa "sandwich panel" ho ka fella ka "modulus" e sebetsang hantle haholo ho feta e thata ka ho fetisisa23. Ntle le moo, boitšoaro bo kobehang ba maballo a laminated 24 kapa auxetic core tubes 25 bo ka ntlafatsoa ka algorithm ea optimization. Ho na le lithuto tse ling mabapi le tlhahlobo ea mochini ea meaho ea sandwich ea mantlha e atolositsoeng tlas'a meroalo e rarahaneng ho feta. Mohlala, tlhahlobo ea khatello ea li-composite tsa konkreite tse nang le li-aggregates tsa auxetic, liphanele tsa sandwich tlas'a meroalo e phatlohang27, liteko tsa ho kobeha28 le liteko tsa tšusumetso ea lebelo le tlase29, hammoho le tlhahlobo ea ho kobeha ho sa tsitsang ha liphanele tsa sandwich tse nang le likarolo tse fapaneng tsa auxetic30.
Hobane papiso ea likhomphutha le liteko tsa liteko tsa meralo e joalo hangata li ja nako ebile li bitsa chelete e ngata, ho hlokahala hore ho hlahisoe mekhoa ea khopolo-taba e ka fanang ka tlhaiso-leseling e hlokahalang bakeng sa ho rala meaho ea mantlha ea auxetic ea multilayer tlas'a maemo a ho jarolla ka mokhoa o sa reroang. nako e loketseng. Leha ho le joalo, mekhoa ea kajeno ea tlhahlobo e na le mefokolo e mengata. Haholo-holo, likhopolo tsena ha li nepahale ho lekana ho bolela esale pele boitšoaro ba lisebelisoa tse nang le motsoako o motenya le ho sekaseka metsoako e entsoeng ka lisebelisoa tse 'maloa tse nang le thepa e fapaneng haholo.
Kaha mehlala ena ea ho hlahloba e itšetlehile ka meroalo e sebelisitsoeng le maemo a moeli, mona re tla lebisa tlhokomelo ho boitšoaro bo feto-fetohang ba liphanele tsa sandwich tsa auxetic core. Khopolo e lekanang ea lera le le leng e sebelisoang bakeng sa litlhahlobo tse joalo e ke ke ea bolela esale pele ka nepo khatello ea ho kuta le ea axial ka har'a li-laminate tse se nang homogeneous ka har'a metsoako ea sandwich ea botenya bo itekanetseng. Ho feta moo, likhopolong tse ling (mohlala, khopolong ea layered), palo ea mefuta-futa ea kinematic (mohlala, ho falla, velocity, joalo-joalo) e itšetlehile haholo ka palo ea lihlopha. Sena se bolela hore tšimo ea motsamao oa lera e 'ngoe le e' ngoe e ka hlalosoa ka boithaopo, ha e ntse e khotsofatsa lithibelo tse itseng tsa ho tsoela pele ha 'mele. Ka hona, sena se lebisa tlhokomelong ea palo e kholo ea mefuta-futa ea mohlala, e leng se etsang hore mokhoa ona o theko e boima. Ho hlola mefokolo ena, re sisinya mokhoa o ipapisitseng le thuto ea zigzag, sehlopha se ikhethileng sa thuto ea maemo a mangata. Khopolo e fana ka tsoelo-pele ea khatello ea ho kuta ho pholletsa le botenya ba laminate, ho nka mokhoa oa zigzag oa ho falla ha sefofaneng. Ka hona, khopolo ea zigzag e fana ka palo e tšoanang ea mefuta-futa ea kinematic ho sa tsotellehe palo ea lihlopha tsa laminate.
Ho bonts'a matla a mokhoa oa rona oa ho bolela esale pele boitšoaro ba liphanele tsa sandwich tse nang le li-concave cores tlas'a meroalo e kobehang, re ile ra bapisa liphetho tsa rona le likhopolo tsa khale (ke hore, mokhoa oa rona oa ho sebelisa mekhoa ea khomphutha (ke hore likarolo tse felletseng) le data ea liteko (ke hore 3D printed sandwich panels).Ho fihlela sena, re ile ra qala ka ho fumana kamano ea ho falla e thehiloeng khopolong ea zigzag, 'me ra fumana li-equations tsa constitutive ka ho sebelisa molao-motheo oa Hamilton' me ra li rarolla ka mokhoa oa Galerkin. Liphetho tse fumanoeng ke sesebelisoa se matla sa moralo o lumellanang likarolo tsa geometri tsa liphanele tsa sandwich tse nang le li-auxetic fillers, li thusa ho batla meaho e nang le thepa e ntlafalitsoeng ea mochini.
Nahana ka karolo e meraro ea sandwich (setšoantšo sa 1). Mekhahlelo ea moralo oa Jiometri: lera le ka holimo \({h}_{t}\), lera le bohareng \({h}_{c}\) le lera le tlase \({h}_{ b }\) botenya. Re nahana hore motheo oa moralo o na le sebopeho sa sekoti se nang le sekoti. Sebopeho se na le lisele tsa motheo tse hlophisitsoeng haufi le tse ling ka mokhoa o hlophisitsoeng. Ka ho fetola liparamente tsa geometric tsa sebopeho sa concave, hoa khoneha ho fetola thepa ea eona ea mochini (ke hore, boleng ba karolelano ea Poisson le ho tiea ha elastic). Mekhahlelo ea geometri ea sele ea mantlha e bonts'oa ho Feiga. 1 ho kenyelletsa le angle (θ), bolelele (h), bophahamo (L) le botenya ba kholomo (t).
Khopolo-taba ea zigzag e fana ka likhakanyo tse nepahetseng haholo tsa khatello ea maikutlo le boits'oaro ba khatello ea meaho e kopaneng ea botenya bo itekanetseng. Phallo ea sebopeho mohopolong oa zigzag e na le likarolo tse peli. Karolo ea pele e bontša boitšoaro ba sandwich panel ka kakaretso, ha karolo ea bobeli e sheba boitšoaro pakeng tsa lihlopha ho etsa bonnete ba ho tsoela pele ha khatello ea ho kuta (kapa seo ho thoeng ke mosebetsi oa zigzag). Ho phaella moo, karolo ea zigzag e nyamela ka ntle ho laminate, eseng ka hare ho lera lena. Ka hona, ts'ebetso ea zigzag e tiisa hore karolo e 'ngoe le e' ngoe e kenya letsoho ho senyeha ha likarolo tsohle. Phapang ena ea bohlokoa e fana ka kabo ea sebele ea 'mele ea ts'ebetso ea zigzag ha e bapisoa le mesebetsi e meng ea zigzag. Mokhoa oa hona joale oa zigzag o fetotsoeng ha o fane ka tsoelo-pele ea khatello ea ho kuta ka mose ho lera le bohareng. Ka hona, sebaka sa phalliso se thehiloeng khopolong ea zigzag se ka ngoloa ka tsela e latelang31.
ka tekano. (1), k=b, c le t li emela matlalo a tlase, a bohareng le a holimo ka ho latellana. Sebaka sa ho falla sa sefofane se bolelang haufi le axis ea Cartesian (x, y, z) ke (u, v, w), 'me potoloho e kobehang sefofaneng mabapi le (x, y) axis ke \({\ uptheta} _ {x}\) le \ ({\ uptheta}_{y}\). \({\psi}_{x}\) le \({\psi}_{y}\) ke boholo ba sebaka sa ho potoloha ha zigzag, le \({\phi}_{x}^{k}\ le letšehali ( z \right)\) le \({\phi}_{y}^{k}\left(z\right)\) ke mesebetsi ea li-zigzag.
Bophahamo ba zigzag ke mosebetsi oa vector oa karabo ea sebele ea poleiti ho mojaro o sebelisitsoeng. Li fana ka tekanyo e loketseng ea ts'ebetso ea zigzag, kahoo e laola monehelo oa kakaretso oa zigzag ho falla ha sefofane. Sekhahla ho pholletsa le botenya ba poleiti bo na le likarolo tse peli. Karolo ea pele ke sekhahla sa ho kuta, se ts'oanang ho pholletsa le botenya ba laminate, 'me karolo ea bobeli ke ts'ebetso e sa khaotseng, e ts'oanang ho pholletsa le botenya ba lera le leng le le leng. Ho latela ts'ebetso ena e sa fetoheng, ts'ebetso ea zigzag ea karolo ka 'ngoe e ka ngoloa joalo ka:
ka tekano. (2), \({c}_{11}^{k}\) le \({c}_{22}^{k}\) ke maqhama a elasticity a lera ka leng, 'me h ke kakaretso ea botenya ba disc. Ho feta moo, \({G}_{x}\) le \({G}_{y}\) ke li-coefficients tse lekantsoeng tsa boima ba sekiri, tse hlahisoang joalo ka 31:
Mesebetsi e 'meli ea amplitude ea zigzag (Equation (3)) le mefuta e meng e mehlano e setseng ea kinematic (Equation (2)) ea thuto ea pele ea "shear deformation theory" e etsa sehlopha sa li-kinematics tse supileng tse amanang le phetoho ena e fetotsoeng ea poleiti ea zigzag. Ho nka ho its'etleha ka mokhoa o ts'oanang oa deformation le ho ela hloko khopolo ea zigzag, sebaka sa deformation se tsamaisong ea coordinate ea Cartesian se ka fumanoa joalo ka:
moo \({\varepsilon}_{yy}\) le \({\varepsilon}_{xx}\) e leng kholofalo e tloaelehileng, le \({\gamma}_{yz},{\gamma}_{xz} \ ) le \({\gamma}_{xy}\) ke ho holofala ho kuta.
Ka ho sebelisa molao oa Hooke le ho ela hloko khopolo ea zigzag, kamano pakeng tsa khatello ea kelello le khatello ea letlapa la orthotropic le sebopeho sa "concave lattice" e ka fumanoa ho tsoa ho equation (1). (5) 32 moo \({c}_{ij}\) e leng "strain constant of the stress-strain matrix".
moo \({G}_{ij}^{k}\), \({E}_{ij}^{k}\) le \({v}_{ij}^{k}\) li sehiloeng teng matla ke modulus ka mahlakoreng a fapaneng, modulus oa Young le karo-karolelano ea Poisson. Li-coefficients tsena li lekana ka mahlakoreng 'ohle bakeng sa lera la isotopic. Ho phaella moo, bakeng sa li-nuclei tse khutlang tsa lesela, joalokaha ho bontšitsoe setšoantšong sa 1, thepa ena e ka ngoloa hape e le 33.
Tšebeliso ea molao-motheo oa Hamilton ho equation ea motsamao oa poleiti ea multilayer e nang le konokono ea "concave lattice" e fana ka lipalo tsa motheo bakeng sa moralo. Molao-motheo oa Hamilton o ka ngoloa e le:
Har'a bona, δ e emela mochine o fapaneng, U e emela matla a ka bang teng, 'me W e emela mosebetsi o etsoang ke matla a ka ntle. Kakaretso ea matla a matla a ka bang teng a fumanoa ho sebelisoa equation. (9), moo A e leng sebaka sa sefofane se bohareng.
Ho nka ts'ebetso e ts'oanang ea mojaro (p) ka tataiso ea z, mosebetsi oa matla a kantle o ka fumanoa ho tsoa ho foromo e latelang:
Ho fetola equation (4) le (5) (9) le sebaka sa equation. (9) le (10) (8) le ho kopanya holim'a botenya ba poleiti, equation: (8) e ka ngoloa hape e le:
Lenane \(\phi\) le emetse ts'ebetso ea zigzag, \({N}_{ij}\) le \({Q}_{iz}\) ke matla a kenang le ho tsoa sefofaneng, \({M} _{ij }\) e emela motsotso oa ho kobeha, 'me mokhoa oa ho bala o tjena:
Ho sebelisa kopanyo ka likarolo ho equation. Ho fetola foromo (12) le ho bala coefficient of variation, defining equation ea sandwich panel e ka fumanoa ka mokhoa oa formula (12). (13).
Li-equation tsa taolo ea phapang bakeng sa lipoleiti tse tharo tse tšehetsoeng ka bolokolohi li rarolloa ka mokhoa oa Galerkin. Tlas'a monahano oa maemo a quasi-static, mosebetsi o sa tsejoeng o nkoa e le equation: (14).
\({u}_{m,n}\), \({v}_{m,n}\), \({w}_{m,n}\),\({{\ uptheta}_ {\mathrm {x}}}_{\mathrm {m} \text{,n}}\),\({{\ uptheta }_{\mathrm {y}}}_{\mathrm {m} \text {,n}}\), \({{\uppsi}_{\mathrm{x}}_{\mathrm{m}\text{,n}}\) le \({{\uppsi}_{ \mathrm{y}}_{\mathrm{m}\text{,n}}\) ke lintlha tse sa tsejoeng tse ka fumanoang ka ho fokotsa phoso. \(\ overline{\ overline{u}} \left({x{\text{,y}}} \ ka ho le letona)\), \(\ overline{\ overline{v}} \left({x{\text {,y}}} \ ka ho le letona)\), \(\ overline{\ overline{w}} \left( {x{\ text{,y}}} \ ka ho le letona)\), \(\ overline{\ overline {{{\ uptheta}_{x}}}} \ ka ho le letšehali ( {x{\ mongolo{, y}}} \ ka ho le letona)\), \(\ overline{\ overline{{{\ uptheta}_{y} }}} \ ka ho le letšehali( {x{\ mongolo{, y}}} \ ka ho le letona)\), \(\ overline{\ overline{{\psi_{x}}}} \left( {x{\ text{, y}}} \ ka ho le letona)\) le \(\ overline{\ overline{{ \psi_{y} }}} \left( {x{\ text{,y}}} \ right)\) ke mesebetsi ea teko, e tlamehang ho khotsofatsa bonyane maemo a hlokahalang a moeli. Bakeng sa maemo a moeli a tšehetsoeng feela, mosebetsi oa teko o ka baloa hape e le:
Phapanyetsano ea li-equations e fana ka lipalo tsa algebra. (14) ho li-equations tse laolang, tse ka lebisang ho fumana li-coefficients tse sa tsejoeng ka equation (14). (14).
Re sebelisa finite element modelling (FEM) ho etsisa komporo ho kobeha ha phanele ea sandwich e tšehelitsoeng ka bolokolohi e nang le sebopeho sa "concave lattice" joalo ka mantlha. Tlhahlobo e entsoe ka khoutu ea likarolo tsa khoebo (mohlala, mofuta oa Abaqus 6.12.1). 3D hexahedral solid elements (C3D8R) e nang le kopanyo e nolofalitsoeng e ile ea sebelisoa ho etsa mohlala oa lihlopha tse ka holimo le tse ka tlaase, 'me li-linear tetrahedral elements (C3D4) li ile tsa sebelisoa ho etsa mohlala oa sebopeho sa "concave" se mahareng. Re entse tlhahlobo ea kutlo ea li-mesh ho leka ho kopana ha mesh mme ra fihlela qeto ea hore liphetho tsa phalliso li ile tsa kopana ka boholo bo bonyenyane ka ho fetisisa har'a mekhahlelo e meraro. Letlapa la sandwich le laeloa ho sebelisoa mosebetsi oa sinusoidal load, ho nahanoa ka maemo a moeli a tšehetsoeng ka bolokolohi metseng e mene. The linear elastic mechanical behavior e nkoa e le mohlala oa thepa o abetsoeng likarolo tsohle. Ha ho na kamano e khethehileng pakeng tsa lihlopha, li hokahane.
Re sebelisitse mekhoa ea khatiso ea 3D ho theha prototype ea rona (ke hore triple printed auxetic core sandwich panel) le setupo sa liteko tse tsamaellanang ho sebelisa maemo a tšoanang a ho kobeha (uniform load p ho latela z-direction) le maemo a moeli (ke hore. ho nahanoa ka mokhoa oa rona oa ho hlahloba (setšoantšo sa 1).
Panele ea sandwich e hatisitsoeng ka printa ea 3D e na le matlalo a mabeli (ka holimo le tlase) le mokokotlo oa "concave lattice", litekanyo tsa ona li bonts'itsoeng ho Lethathamo la 1, 'me li entsoe ka mochine oa khatiso oa Ultimaker 3 3D (Italy) ho sebelisoa mokhoa oa ho beha. FDM). theknoloji e sebelisoa ts'ebetsong ea eona. Re 3D re hatisitse poleiti ea motheo le sebopeho se seholo sa li-auxetic lattice hammoho, 'me ra hatisa karolo e ka holimo ka thoko. Sena se thusa ho qoba mathata leha e le afe nakong ea ts'ebetso ea ho tlosa tšehetso haeba moqapi oohle o lokela ho hatisoa hang-hang. Ka mor'a khatiso ea 3D, likarolo tse peli tse arohaneng li kopanngoa hammoho ho sebelisa superglue. Re hatisitse likarolo tsena re sebelisa polylactic acid (PLA) ka bongata bo phahameng ka ho fetisisa ba infill (ke hore 100%) ho thibela mefokolo leha e le efe ea khatiso ea sebakeng seo.
Sistimi ea clamping ea tloaelo e etsisa maemo a tšoanang a bonolo a moeli a ts'ehetsoeng a amohetsoeng mofuteng oa rona oa tlhahlobo. Sena se bolela hore mokhoa oa ho ts'oara o thibela boto hore e se ke ea tsamaea ka mahlakoreng a x le y, e lumella likarolo tsena ho potoloha ka bolokolohi ho pota-potile lilepe tsa x le y. Sena se etsoa ka ho nahana ka li-fillets tse nang le radius r = h / 2 lipheletsong tse 'nè tsa tsamaiso ea ho tšoara (setšoantšo sa 2). Mokhoa ona oa ho koala o boetse o tiisa hore mojaro o sebelisitsoeng o fetisoa ka ho feletseng ho tloha mochine oa ho hlahloba ho ea ho phanele 'me o tsamaisana le mohala o bohareng oa phanele (setšoantšo sa 2). Re sebelisitse theknoloji ea khatiso ea 3D ea mefuta e mengata (ObjetJ735 Connex3, Stratasys® Ltd., USA) le li-resin tse thata tsa khoebo (tse kang Vero series) ho hatisa mokhoa oa ho tšoara.
Sets'oants'o sa moralo oa sistimi e hatisitsoeng e hatisitsoeng ea 3D le kopano ea eona e nang le phanele ea sandwich e hatisitsoeng ea 3D e nang le auxetic core.
Re etsa liteko tse laoloang ke motsamao oa quasi-static compression re sebelisa benche ea tlhahlobo ea mochini (Lloyd LR, load cell = 100 N) mme re bokella matla a mochini le phalliso ka sekhahla sa sampole sa 20 Hz.
Karolo ena e fana ka thuto ea lipalo ea sebopeho sa sandwich se sisintsoeng. Re nka hore likarolo tse ka holimo le tse ka tlaase li entsoe ka carbon epoxy resin, 'me sebopeho sa lesela sa mokokotlo oa concave se entsoe ka polymer. Thepa ea mechine ea thepa e sebelisitsoeng thutong ena e bontšoa ho Lethathamo la 2. Ho phaella moo, litekanyo tse se nang moeli tsa liphello tsa ho falla le masimo a khatello li bontšoa ho Lethathamo la 3.
Phallo e phahameng ka ho fetesisa e se nang moeli ea poleiti e ts'ehelitsoeng ka bolokolohi e ts'ehelitsoeng ka mokhoa o ts'oanang e bapisoa le liphetho tse fumanoeng ka mekhoa e fapaneng (Letlapa la 4). Ho na le tumellano e ntle lipakeng tsa khopolo e sisintsoeng, mokhoa o lekanyelitsoeng le litiiso tsa liteko.
Re ile ra bapisa ho falla ka mokhoa o otlolohileng oa khopolo ea zigzag e fetotsoeng (RZT) e nang le 3D elasticity theory (Pagano), theory first order deformation theory (FSDT), le liphetho tsa FEM (bona Setšoantšo sa 3). Khopolo ea pele ea ho kuta, e thehiloeng ho litšoantšo tsa ho falla ha lipoleiti tse teteaneng tsa multilayer, e fapane haholo le tharollo ea elastic. Leha ho le joalo, khopolo e fetotsoeng ea zigzag e bolela esale pele liphello tse nepahetseng haholo. Ho phaella moo, re boetse re bapisa khatello ea ho kuta ka ntle ho sefofane le khatello e tloaelehileng ea sefofaneng sa likhopolo tse sa tšoaneng, tseo har'a tsona khopolo ea zigzag e ileng ea fumana liphello tse nepahetseng ho feta FSDT (setšoantšo sa 4).
Papiso ea khatello e tloaelehileng e emeng e baloang ho sebelisoa likhopolo tse fapaneng ho y = b/2.
Phetoho ea khatello ea kelello (a) le khatello e tloaelehileng (b) ho pholletsa le botenya ba sandwich panel, e baloang ho sebelisoa likhopolo tse fapaneng.
Ka mor'a moo, re ile ra hlahloba tšusumetso ea liparamente tsa geometri tsa sele ea yuniti e nang le mokokotlo oa concave holim'a thepa eohle ea mochine oa sandwich panel. Sekhahla sa sele ea yuniti ke parameter ea bohlokoa ka ho fetisisa ea li-geometric moralong oa meaho ea reentrant lattice34,35,36. Ka hona, re balile tšusumetso ea yuniti selefouno angle, hammoho le botenya ka ntle ho mantlha, ka ho kheloha kakaretso ea poleiti (sa feiga. 5). Ha botenya ba lera le bohareng bo ntse bo eketseha, ho kheloha ho se nang dimension ho ea fokotseha. Matla a ho kobeha a lekanyelitsoeng a eketseha bakeng sa likarolo tse teteaneng tsa mantlha le ha \(\frac{{h}_{c}}{h}=1\) (ke hore, ha ho na le lera le le leng la concave). Liphanele tsa li-sandwich tse nang le sele ea auxetic unit (e leng \(\theta = 70^\circ\)) li na le libaka tse nyenyane ka ho fetisisa (Setšoantšo sa 5). Sena se bontša hore matla a ho kobeha ha mokokotlo oa auxetic a phahame ho feta a tloaelehileng a auxetic core, empa ha a sebetse hantle ebile a na le karolelano e ntle ea Poisson.
Ho kheloha ho hoholo ho tloaelehileng ha molamu oa "concave lattice" o nang le li-angles tse fapaneng tsa lisele le botenya ba kantle ho sefofane.
Botenya ba mantlha ba grating ea auxetic le karolo ea likarolo (e leng \(\theta=70^\circ\)) e ama ho falla ho hoholo ha poleiti ea sandwich (Setšoantšo sa 6). Ho ka bonoa hore ho kheloha ho hoholo ha poleiti ho eketseha ka ho eketseha ha h / l. Ho phaella moo, ho eketsa botenya ba mokokotlo oa auxetic ho fokotsa porosity ea sebopeho sa concave, kahoo ho eketsa matla a ho koba a sebopeho.
Ho kheloha ho hoholo ha liphanele tsa sandwich tse bakoang ke meaho ea lattice e nang le mantlha ea botenya le bolelele bo fapaneng.
Boithuto ba mafapha a khatello ea maikutlo ke sebaka se khahlisang se ka hlahlojoang ka ho fetola liparamente tsa geometri tsa sele ea yuniti ho ithuta mekhoa ea ho hloleha (mohlala, delamination) ea meaho e mengata. Karo-karolelano ea Poisson e na le phello e kholo tšimong ea khatello ea ho kuta ka ntle ho sefofane ho feta khatello ea kelello e tloaelehileng (bona setšoantšo sa 7). Ho phaella moo, phello ena e inhomogeneous ka litsela tse fapaneng ka lebaka la thepa ea orthotropic ea thepa ea gratings tsena. Likarolo tse ling tsa geometri, tse kang botenya, bophahamo le bolelele ba mehaho ea concave, li ne li e-na le phello e fokolang tšimong ea khatello ea kelello, kahoo ha lia ka tsa hlahlojoa thutong ena.
Fetola likarolo tsa khatello ea ho kuta ka mekhahlelo e fapaneng ea phanele ea sandwich e nang le sethapo se nang le li-angles tse fapaneng tsa concavity.
Mona, matla a kobehang a poleiti ea multilayer e tšehelitsoeng ka bolokolohi e nang le konokono ea "concave lattice" e batlisisoa ho sebelisoa khopolo ea zigzag. Tlhahiso e reriloeng e bapisoa le likhopolo-taba tse ling tsa khale, tse kenyeletsang khopolo ea elasticity ea mahlakore a mararo, thuto ea pele ea ho kheloha ha ho kuta, le FEM. Re boetse re netefatsa mokhoa oa rona ka ho bapisa liphetho tsa rona le liphetho tsa liteko ho meaho ea sandwich e hatisitsoeng ea 3D. Liphetho tsa rona li bonts'a hore mohopolo oa zigzag o khona ho bolela esale pele ho senyeha ha meaho ea sandwich ea botenya bo itekanetseng tlasa meroalo e kobehang. Ho feta moo, ho ile ha hlahlobisisoa tšusumetso ea litekanyo tsa geometri tsa sebopeho sa "concave lattice" boitšoarong ba ho kobeha ha liphanele tsa sandwich. Liphello li bontša hore ha boemo ba auxetic bo ntse bo eketseha (ke hore, θ <90), matla a ho khumama a eketseha. Ntle le moo, ho eketsa sekhahla sa karolo le ho fokotsa botenya ba mantlha ho tla fokotsa matla a ho kobeha a phanele ea sandwich. Qetellong, phello ea karo-karolelano ea Poisson mabapi le khatello ea ho kuta ka ntle ho sefofane e ithutoa, 'me ho netefatsoa hore karo-karolelano ea Poisson e na le tšusumetso e kholo ka ho fetisisa khatellong ea ho kuta e hlahisoang ke botenya ba poleiti ea laminated. Litlhaloso le liqeto tse reriloeng li ka bula tsela ea ho rala le ho ntlafatsa meaho ea li-multilayer tse nang le li-fillers tsa concave lattice tlas'a maemo a thata a ho laela a hlokahalang bakeng sa moralo oa mehaho e jereng mojaro sebakeng sa sefofane le theknoloji ea biomedical.
Lintlha tse sebelisitsoeng le/kapa tse hlahlobiloeng thutong ea hajoale li fumaneha ho tsoa ho bangoli ba fapaneng ka kopo e utloahalang.
Aktai L., Johnson AF le Kreplin B. Kh. Papiso ea lipalo ea litšobotsi tsa timetso ea li-cores tsa khekhe ea linotsi. moenjiniere. fractal. boea. 75(9), 2616–2630 (2008).
Gibson LJ le Ashby MF Porous Solids: Sebopeho le Thepa (Cambridge University Press, 1999).
Nako ea poso: Aug-12-2023