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Ana amfani da tsarin tsarin Sandwich a ko'ina a masana'antu da yawa saboda manyan kayan aikin injin su. Interlayer na waɗannan sifofin abu ne mai mahimmanci don sarrafawa da haɓaka kayan aikin injin su a ƙarƙashin yanayi daban-daban na lodi. Tsarin lattice concave ƙwararrun ƴan takara ne don amfani da su azaman masu shiga tsakani a cikin irin wannan tsarin sanwici saboda dalilai da yawa, wato don daidaita elasticity ɗinsu (misali, ƙimar Poisson da ƙimar taurin ƙarfi) da ductility (misali, babban elasticity) don sauƙi. Ƙarfafa-da-nauyi rabon rabo ana samun su ta hanyar daidaita abubuwa kawai na geometric waɗanda ke haɗa tantanin halitta. Anan, muna bincika martanin sassauƙa na 3-Layer concave core sandwich panel ta amfani da nazari (watau ka'idar zigzag), lissafi (watau ƙayyadaddun abu) da gwaje-gwajen gwaji. Mun kuma yi nazarin tasirin sigogi daban-daban na geometric na tsarin raƙuman raƙuman ruwa (misali kwana, kauri, tsayin tantanin halitta zuwa rabo mai tsayi) akan yanayin injina gabaɗaya na tsarin sanwici. Mun gano cewa ainihin sifofi tare da halayen auxetic (watau ma'auni na Poisson) suna nuna ƙarfin sassauƙa da ƙarancin damuwa daga cikin jirgin idan aka kwatanta da grating na al'ada. Abubuwan da muka gano na iya ba da hanya don haɓaka ingantattun ingantattun gyare-gyare masu yawa tare da manyan lattice na gine-gine don aikace-aikacen sararin samaniya da ilimin halittu.
Saboda girman ƙarfinsu da ƙarancin nauyi, ana amfani da tsarin sanwici sosai a masana'antu da yawa, gami da ƙirar injiniyoyi da kayan wasanni, marine, sararin samaniya, da injiniyan halittu. Tsarin lattice concave shine ɗan takara ɗaya mai yuwuwa da ake ɗaukarsa azaman manyan yadudduka a cikin irin waɗannan sifofi masu haɗaka saboda ƙarfin ɗaukar kuzarinsu mafi girma da kaddarorin ƙarfi-zuwa nauyi1,2,3. A baya, an yi ƙoƙari sosai don zayyana tsarin sanwici marasa nauyi tare da lattices masu raɗaɗi don ƙara haɓaka kayan injin. Misalan irin waɗannan ƙira sun haɗa da manyan matsi a cikin tarkacen jirgin ruwa da masu ɗaukar girgiza a cikin motoci4,5. Dalilin da yasa tsarin madaidaicin madaidaicin ya shahara, na musamman kuma ya dace da ginin panel na sanwici shine ikonsa na daidaita kaddarorin sa na elastomechanical (misali taurin roba da kwatancen Poisson). Ɗayan irin wannan kadarorin mai ban sha'awa shine halayen auxetic (ko ragi na Poisson mara kyau), wanda ke nufin faɗaɗa tsarin sikirin lokacin da aka miƙe a tsayi. Wannan dabi'ar da ba a saba gani ba tana da alaƙa da ƙayyadaddun ƙayyadaddun ƙayyadaddun ƙwayoyin sel na farko7,8,9.
Tun daga farkon binciken Lakes game da samar da kumfa mai auxetic, an yi ƙoƙari sosai don haɓaka sifofi masu ɓarna tare da mummunan rabo na Poisson10,11. An gabatar da nau'ikan geometries da yawa don cimma wannan buri, kamar su chiral, Semi-rigid, da ƙwanƙwaran sel masu jujjuyawa, 12 waɗanda duk suna nuna ɗabi'a. Zuwan fasahar kere-kere (AM, wanda kuma aka sani da bugu na 3D) ya kuma sauƙaƙe aiwatar da waɗannan 2D ko 3D auxetic Tsarin13.
Halin auxetic yana ba da kaddarorin inji na musamman. Misali, Tafkuna da Elms14 sun nuna cewa kumfa na auxetic suna da ƙarfin yawan amfanin ƙasa, mafi girman ƙarfin ɗaukar kuzari, da ƙarancin ƙarfi fiye da kumfa na al'ada. Dangane da kaddarorin injiniyoyi masu ƙarfi na kumfa auxetic, suna nuna juriya mafi girma a ƙarƙashin nauyin fashewa mai ƙarfi da haɓakawa mafi girma a ƙarƙashin tsantsar tsantsa15. Bugu da ƙari, yin amfani da fibers auxetic a matsayin kayan ƙarfafawa a cikin abubuwan da aka haɗa za su inganta kayan aikin su na injiniya16 da juriya ga lalacewa ta hanyar fiber stretch17.
Bincike ya kuma nuna cewa yin amfani da sifofi masu ɗorewa a matsayin ginshiƙan sifofi masu lanƙwasa na iya inganta ayyukansu na waje, gami da taurin kai da ƙarfi18. Yin amfani da ƙirar ƙira, an kuma lura cewa ainihin auxetic na iya ƙara ƙarfin karaya na bangarori masu haɗaka19. Abubuwan da aka haɗa tare da zaruruwan auxetic kuma suna hana yaɗuwar fashewa idan aka kwatanta da filaye na al'ada20.
Zhang et al.21 sun tsara yanayin haɗuwa mai ƙarfi na dawo da tsarin tantanin halitta. Sun gano cewa ana iya inganta ƙarfin lantarki da shan kuzari ta hanyar ƙara kusurwar tantanin halitta auxetic, wanda ke haifar da grating tare da mafi ƙarancin rabo na Poisson. Sun kuma ba da shawarar cewa za a iya amfani da irin waɗannan sandunan sanwicin auxetic azaman tsarin kariya daga babban nauyin tasiri. Imbalzano et al.22 kuma ya ruwaito cewa auxetic composite sheets na iya tarwatsa karin makamashi (watau sau biyu) ta hanyar nakasar filastik kuma yana iya rage saurin gudu a gefen baya da 70% idan aka kwatanta da zanen gado guda ɗaya.
A cikin 'yan shekarun nan, an mai da hankali sosai ga nazarin lambobi da gwaji na tsarin sanwici tare da filler auxetic. Waɗannan karatun suna nuna hanyoyin haɓaka kayan aikin injina na waɗannan sifofin sanwici. Misali, la'akari da isasshe mai kauri auxetic a matsayin ginshikin sanwici na iya haifar da ingantacciyar ma'auni na matashi fiye da mafi ƙanƙanta Layer23. Bugu da kari, ana iya inganta halayen lanƙwasa katako na katako 24 ko auxetic core tubes 25 tare da ingantaccen algorithm. Akwai wasu nazarin kan gwajin injina na sifofin sanwici mai faɗaɗawa ƙarƙashin ƙarin hadaddun lodi. Misali, gwajin matsawa na abubuwan da aka haɗa tare da auxetic aggregates, sandwich panels ƙarƙashin abubuwan fashewa27, lankwasawa tests28 da gwajin tasiri mai ƙarancin gudu29, da kuma nazarin lankwasa ba madaidaiciyar lankwasa sanwici tare da bambancin aikin auxetic aggregates30.
Saboda kwamfyutocin kwamfyutoci da kimantawa na gwaji na irin waɗannan ƙirar galibi suna ɗaukar lokaci da tsada, akwai buƙatar haɓaka hanyoyin ka'idoji waɗanda za su iya samar da ingantaccen kuma daidaitaccen bayanin da ake buƙata don ƙira manyan sifofi na auxetic na multilayer a ƙarƙashin yanayin lodi na sabani. m lokaci. Duk da haka, hanyoyin nazarin zamani suna da iyakacin iyaka. Musamman, waɗannan ra'ayoyin ba su dace ba don yin hasashen halayen kayan haɗaɗɗun ƙanƙara da kuma yin nazarin abubuwan da suka haɗa da abubuwa da yawa tare da bambancin kaddarorin roba.
Tun da waɗannan ƙirar ƙididdiga sun dogara da nauyin da aka yi amfani da su da yanayin iyaka, a nan za mu mai da hankali kan ɗabi'a mai sassaucin ra'ayi na auxetic core sandwich panels. Kwatankwacin ka'idar Layer guda ɗaya da aka yi amfani da ita don irin waɗannan nazarce-nazarce ba za ta iya yin hasashen tsastsauran ra'ayi daidai da matsalolin axial ba a cikin laminates marasa daidaituwa a cikin matsakaicin kauri mai kauri. Bugu da ƙari, a cikin wasu ra'ayoyin (misali, a cikin ka'idar da aka yi la'akari), adadin masu canji na kinematic (misali, ƙaura, saurin gudu, da dai sauransu) ya dogara sosai akan adadin yadudduka. Wannan yana nufin cewa filin motsi na kowane Layer za a iya kwatanta shi da kansa, yayin da yake gamsar da wasu matsalolin ci gaba na jiki. Sabili da haka, wannan yana haifar da yin la'akari da adadi mai yawa na masu canji a cikin samfurin, wanda ya sa wannan hanya ta zama mai tsada. Don shawo kan waɗannan iyakoki, muna ba da shawarar wata hanya bisa ka'idar zigzag, ƙayyadaddun ƙayyadaddun ƙayyadaddun ƙa'idar ka'idar matakai masu yawa. Ka'idar tana ba da ci gaba da damuwa mai ƙarfi a cikin kauri na laminate, yana ɗaukar tsarin zigzag na ƙaura a cikin jirgin. Don haka, ka'idar zigzag tana ba da adadin adadin kinematic masu canji ba tare da la'akari da adadin yadudduka a cikin laminate ba.
Don nuna ƙarfin hanyarmu wajen tsinkayar ɗabi'ar sandunan sanwici tare da dunƙule dunƙule a ƙarƙashin nauyin lanƙwasawa, mun kwatanta sakamakonmu tare da ka'idodin gargajiya (watau tsarinmu tare da ƙirar ƙira (watau abubuwa masu iyaka) da bayanan gwaji (watau lankwasa maki uku 3D buga sandwich panels) .Don wannan karshen, mun fara samo dangantakar ƙaura bisa ka'idar zigzag, sa'an nan kuma mun sami ma'auni masu mahimmanci ta amfani da ka'idar Hamilton kuma mun warware su ta amfani da hanyar Galerkin. Sakamakon da aka samu shine kayan aiki mai ƙarfi don ƙira mai dacewa. sigogi na geometric na sandunan sanwici tare da filler auxetic, sauƙaƙe binciken tsarin tare da ingantattun kayan inji.
Yi la'akari da panel sandwich mai Layer uku (Fig. 1). Ma'aunin ƙira na Geometric: saman saman \({h}_{t}\), Layer na tsakiya \({h}_{c}\) da kauri na ƙasa \({h}_{ b}\). Muna tsammanin cewa tushen tsarin yana ƙunshe da tsarin ramin rami. Tsarin ya ƙunshi sel na farko da aka shirya kusa da juna cikin tsari. Ta hanyar canza ma'auni na geometric na tsarin concave, yana yiwuwa a canza kayan aikin injiniya (watau dabi'u na Poisson's ratio da stiffness na roba). Ana nuna sigogin geometrical na tantanin halitta na farko a cikin ɓangarorin. 1 ciki har da kwana (θ), tsayi (h), tsawo (L) da kauri shafi (t).
Ka'idar zigzag tana ba da ingantattun tsinkaya game da damuwa da ɗabi'ar ɗabi'a na sifofi masu kauri mai matsakaicin kauri. Maɓallin tsari a ka'idar zigzag ya ƙunshi sassa biyu. Kashi na farko yana nuna halayen sanwicin gaba ɗaya, yayin da kashi na biyu ya dubi halayen da ke tsakanin yadudduka don tabbatar da ci gaba da damuwa (ko abin da ake kira aikin zigzag). Bugu da ƙari, ɓangaren zigzag yana ɓacewa a saman farfajiyar laminate, kuma ba a cikin wannan Layer ba. Don haka, aikin zigzag yana tabbatar da cewa kowane Layer yana ba da gudummawa ga jimillar nakasar giciye. Wannan muhimmin bambance-bambance yana ba da mafi kyawun rarraba jiki na aikin zigzag idan aka kwatanta da sauran ayyukan zigzag. Samfurin zigzag da aka gyara na yanzu baya samar da ci gaba mai juyi juzu'i tare da matsakaicin Layer. Saboda haka, filin ƙaura bisa ka'idar zigzag za a iya rubuta kamar haka31.
a cikin lissafin. (1), k=b, c da t suna wakiltar kasa, tsakiya da sama, bi da bi. Filin ƙaura na ma'anar jirgin sama tare da axis na Cartesian (x, y, z) shine (u, v, w), kuma jujjuyawar jujjuyawar a cikin jirgin game da (x, y) axis shine \({\uptheta} _ {x}\) da \ ({\uptheta}_{y}\). \({\psi}_{x}\) da \({\psi}_{y}\) sune yawan jujjuyawar zigzag, da \({\phi}_{x}^{k}\ hagu z \right) \) da \({\phi}_{y}^{k} \ hagu(z \ dama) \) ayyuka ne na zigzag.
Girman zigzag shine aikin vector na ainihin martanin farantin zuwa nauyin da aka yi amfani da shi. Suna samar da ma'auni mai dacewa na aikin zigzag, ta haka ne ke sarrafa duk gudunmawar zigzag zuwa ƙaura a cikin jirgin sama. Ƙarƙashin ƙarfi a fadin kaurin farantin ya ƙunshi sassa biyu. Bangare na farko shine kusurwar shear, uniform a fadin kauri na laminate, kashi na biyu kuma aiki ne na dindindin na yanki guda ɗaya, iri ɗaya a fadin kauri na kowane ɗayan. Dangane da waɗannan ayyuka akai-akai, ana iya rubuta aikin zigzag na kowane Layer kamar:
a cikin lissafin. (2), \({c}_{11}^{k}\) da \({c}_{22}^{k}\) su ne ma'aunin elasticity na kowane Layer, kuma h shine jimlar kauri. diski. Bugu da kari, \({G}_{x}\) da \({G}_{y}\) sune ma'aunin ma'aunin ma'aunin ƙarfi mai ƙarfi, wanda aka bayyana kamar 31:
Ayyukan amplitude na zigzag guda biyu (Equation (3)) da sauran ma'aunin kinematic biyar (Equation (2)) na ka'idar nakasar oda ta farko sun ƙunshi saitin kinematics bakwai masu alaƙa da wannan canjin ka'idar farantin farantin zigzag da aka gyara. Yin la'akari da dogaro na layi na nakasawa da kuma la'akari da ka'idar zigzag, ana iya samun filin nakasar a cikin tsarin haɗin gwiwar Cartesian kamar:
inda \({\varepsilon}_{yy}\) da \({\varepsilon}_{xx}\) sune nakasar al'ada, da kuma \({\gamma}_{yz},{\gamma}_{xz} \ ) da \({\gamma}_{xy}\) nakasar juzu'i ne.
Yin amfani da dokar Hooke da yin la'akari da ka'idar zigzag, ana iya samun alaƙar da ke tsakanin damuwa da damuwa na farantin orthotropic tare da tsarin lattice concave daga lissafin (1). (5)32 inda \({c}_{ij}\) shine madaidaicin matrix na damuwa.
inda aka yanke \({G}_{ij}^{k}\), \({E}_{ij}^{k}\) da \({v}_{ij}^{k}\) karfi shine modules ta bangarori daban-daban, Matsakaicin Matasa da Rabon Poisson. Waɗannan ƙayyadaddun ƙididdiga daidai suke a duk kwatance don layin isotopic. Bugu da kari, don dawowar nuclei na lattice, kamar yadda aka nuna a cikin siffa 1, ana iya sake rubuta waɗannan kaddarorin a matsayin 33.
Aiwatar da ƙa'idar Hamilton zuwa ma'auni na motsi na farantin multilayer tare da madaidaicin lattice core yana ba da ainihin ma'auni don ƙira. Ana iya rubuta ƙa'idar Hamilton kamar:
Daga cikin su, δ yana wakiltar ma'aikacin bambance-bambancen, U yana wakiltar ƙarfin ƙarfin kuzari, kuma W yana wakiltar aikin da ƙarfin waje ya yi. Ana samun jimillar yuwuwar ƙarfin kuzari ta amfani da ma'auni. (9), inda A shine yankin tsakiyar jirgin sama.
Yin la'akari da aikace-aikacen kayan aiki na kaya (p) a cikin hanyar z, ana iya samun aikin ƙarfin waje daga wannan tsari:
Sauya ma'auni (4) da (5) (9) da maye gurbin lissafin. (9) da (10) (8) da haɗa kan kaurin farantin, ƙila: (8) za a iya sake rubutawa kamar:
Fihirisar \(\phi\) tana wakiltar aikin zigzag, \({N}_{ij}\) da \({Q}_{iz}\) sojojin ne a ciki da wajen jirgin, \({M}) _{ij }\) yana wakiltar lokacin lanƙwasawa, kuma tsarin lissafin shine kamar haka:
Aiwatar da haɗin kai ta sassa zuwa lissafin. Musanya cikin dabara (12) da ƙididdige ƙididdige ƙididdiga na bambancin, ana iya samun ma'anar ma'aunin sanwici ta hanyar dabara (12). (13).
Matsalolin sarrafawa na bambance-bambance don faranti mai Layer uku masu goyan baya an warware su ta hanyar Galerkin. Ƙarƙashin zato na ƙayyadaddun yanayi, aikin da ba a san shi ba ana ɗaukarsa azaman lissafi: (14).
\({u}_{m,n}\), \({v}_{m,n}\), \({w}_{m,n}\),\({{\uptheta}_ {\mathrm {x}}}_{\mathrm {m} \text{,n}}\),\({{\uptheta }_{\mathrm {y}}}_{\mathrm {m} \ rubutu {,n}}\), \({{\uppsi}_{\mathrm{x}}}_{\mathrm{m}\text{,n}}\) da \({{\uppsi}_{ \mathrm{y}}}_{\mathrm{m}\text{,n}}\) su ne da ba a san su ba waɗanda za a iya samu ta hanyar rage kuskure. \(\overline{\overline{u}} hagu ({x{\text{,y}}} \ dama)\), \(\overline{\overline{v}} hagu({x{\text) {,y}}} \dama)\), \(\overline{\overline{w}} \hagu( {x{\text{,y}}} \ dama)\), \(\overline{\overline {{\uptheta}_{x}}} \hagu( {x{\text{,y}}} \dama)\), \(\overline{\overline{{{\uptheta}_{y} }}} \hagu( {x{\text{,y}}} \dama)\), \(\overline{\overline{{\psi_{x}}} \ hagu( {x{\text{, y}}} \dama)\) da \(\overline{\overline{{ \psi_{y}}}} \hagu( {x{\text{,y}}} \dama)\) ayyuka ne na gwaji, wanda dole ne ya gamsar da mafi ƙarancin buƙatun iyakokin iyaka. Don kawai goyan bayan sharuɗɗan iyaka, ana iya ƙididdige aikin gwajin kamar:
Sauya ma'auni yana ba da lissafin algebraic. (14) zuwa ma'auni na gudanarwa, wanda zai iya haifar da samun adadin da ba a sani ba a cikin lissafi (14). (14).
Muna amfani da ƙirar ƙira mai iyaka (FEM) don yin kwamfyuta-kwaikwayi lankwasa panel ɗin sanwici mai goyan bayan kyauta tare da tsarin lattice mai maƙarƙashiya a matsayin ainihin. An gudanar da binciken ne a cikin lambar ƙayyadaddun ƙayyadaddun abubuwa na kasuwanci (misali, sigar Abaqus 6.12.1). 3D hexahedral m abubuwa (C3D8R) tare da sauƙaƙe haɗin kai an yi amfani da su don yin samfuri na sama da ƙasa yadudduka, kuma an yi amfani da abubuwan tetrahedral na layi (C3D4) don ƙirar tsaka-tsaki (concave) tsarin lattice. Mun gudanar da bincike na ji na raga don gwada haɗuwar ragar kuma mun kammala cewa sakamakon ƙaura ya haɗu a mafi ƙanƙanta girman siffa a tsakanin yadudduka uku. Ana ɗora farantin sanwici ta amfani da aikin nauyin nauyin sinusoidal, la'akari da yanayin iyaka da aka goyan bayan kyauta a gefuna huɗu. Ana ɗaukar halayen injin na roba na linzamin kwamfuta azaman ƙirar kayan da aka sanya wa duk yadudduka. Babu takamaiman lamba tsakanin yadudduka, an haɗa su.
Mun yi amfani da dabarun bugu na 3D don ƙirƙirar samfurin mu (watau bugu uku auxetic core sandwich panel) da daidaitaccen saitin gwaji na al'ada don amfani da yanayin lanƙwasa irin wannan (load p tare da z-direction) da yanayin iyaka (watau kawai goyan baya). ɗauka a cikin tsarin nazarin mu (Fig. 1).
Sandwich panel da aka buga akan firinta na 3D ya ƙunshi fatun guda biyu (na sama da ƙasa) da kuma ƙwanƙolin lattice core, girman wanda aka nuna a cikin Tebu 1, kuma an kera shi akan firintar Ultimaker 3 3D (Italiya) ta amfani da hanyar sanyawa (Italiya). FDM). ana amfani da fasaha a cikin tsarinta. Mun 3D buga farantin tushe da babban auxetic lattice tsarin tare, kuma buga saman Layer dabam. Wannan yana taimakawa wajen guje wa duk wani rikitarwa yayin aikin cire tallafi idan duk ƙirar dole ne a buga a lokaci ɗaya. Bayan bugu na 3D, sassa biyu daban-daban suna manne tare ta amfani da superglue. Mun buga waɗannan abubuwan da aka gyara ta amfani da polylactic acid (PLA) a mafi girman maɗauri (watau 100%) don hana kowane lahani na bugu.
Tsarin ƙwanƙwasa na al'ada yana kwaikwayon yanayin ƙayyadaddun ƙayyadaddun ƙayyadaddun tallafi waɗanda aka ɗauka a cikin ƙirar mu. Wannan yana nufin cewa tsarin riko yana hana allon motsi tare da gefuna a cikin kwatance x da y, yana barin waɗannan gefuna su juya cikin yardar kaina kewaye da gatari x da y. Ana yin wannan ta hanyar la'akari da fillet tare da radius r = h / 2 a gefuna hudu na tsarin gripping (Fig. 2). Wannan tsarin ƙaddamarwa kuma yana tabbatar da cewa an cika nauyin da aka yi amfani da shi daga na'urar gwaji zuwa panel kuma ya daidaita tare da tsakiyar layi na panel (fig. 2). Mun yi amfani da fasahar bugu 3D da yawa jet (ObjetJ735 Connex3, Stratasys® Ltd., Amurka) da resins na kasuwanci masu tsauri (kamar jerin Vero) don buga tsarin riko.
Tsarin tsari na 3D bugu na al'ada gripping tsarin da taron sa tare da 3D bugu sanwici panel tare da auxetic core.
Muna yin gwaje-gwajen matsawa mai juzu'i mai sarrafa motsi ta amfani da benci na gwaji na inji (Lloyd LR, load cell = 100 N) kuma muna tattara sojojin injina da ƙaura a ƙimar samfur na 20 Hz.
Wannan sashe yana gabatar da nazarin lambobi na tsarin sanwici da aka tsara. Muna ɗauka cewa saman da kasa yadudduka an yi su da carbon epoxy guduro, da lattice tsarin na concave core yi ne da polymer. Ana nuna kaddarorin injiniyoyi na kayan da aka yi amfani da su a cikin wannan binciken a cikin Tebur 2. Bugu da ƙari, ana nuna ma'auni maras girma na sakamakon ƙaura da filayen damuwa a cikin Table 3.
Matsakaicin matsaya mara nauyi na farantin da aka ɗora wa kyauta kyauta an kwatanta shi da sakamakon da aka samu ta hanyoyi daban-daban (Table 4). Akwai kyakkyawar yarjejeniya tsakanin ka'idar da aka tsara, hanyar ƙayyadaddun ƙayyadaddun ƙayyadaddun abubuwa da kuma tabbacin gwaji.
Mun kwatanta ƙaura ta tsaye na ka'idar zigzag da aka gyara (RZT) tare da ka'idar elasticity na 3D (Pagano), ka'idar nakasawa ta farko (FSDT), da sakamakon FEM (duba siffa 3). Ka'idar juzu'i na farko, dangane da zane-zanen ƙaura na faranti mai kauri, ya bambanta da mafi yawan bayani na roba. Koyaya, ka'idar zigzag da aka gyara tana annabta ingantaccen sakamako. Bugu da ƙari, mun kuma kwatanta damuwa da damuwa na waje da jirgin sama na al'ada na ka'idoji daban-daban, daga cikin abin da ka'idar zigzag ta sami sakamako mai kyau fiye da FSDT (Fig. 4).
Kwatanta nau'in madaidaicin daidaitacce wanda aka lissafta ta amfani da dabaru daban-daban a y = b/2.
Canji a cikin damuwa mai ƙarfi (a) da damuwa na yau da kullun (b) a cikin kauri na panel sanwici, ƙididdiga ta amfani da dabaru daban-daban.
Bayan haka, mun bincika tasirin ma'auni na geometric na tantanin halitta tare da madaidaicin madaidaicin madaidaicin kayan injin gabaɗaya na panel sandwich. Ƙaƙwalwar tantanin halitta ita ce mafi mahimmancin ma'auni na geometric a cikin ƙirar reentrant sigar lattice34,35,36. Sabili da haka, mun ƙididdige tasiri na kusurwar tantanin halitta, da kuma kauri a waje da ainihin, akan jimlar juzu'i na farantin (Fig. 5). Yayin da kauri na tsaka-tsakin ya karu, matsakaicin juzu'i mara nauyi yana raguwa. Ƙarfin lanƙwasawa na dangi yana ƙaruwa don manyan yadudduka masu kauri kuma lokacin da \(\ frac {{h}_{c}}{h}=1 \) (watau lokacin da akwai Layer concave ɗaya). Sandwich panels tare da auxetic naúrar tantanin halitta (watau (\theta =70^\circ\)) suna da mafi ƙanƙanta ƙaura (Fig. 5). Wannan yana nuna cewa ƙarfin lanƙwasawa na auxetic core ya fi na al'ada auxetic core, amma ba shi da inganci kuma yana da ingantaccen rabo na Poisson.
Matsakaicin matsakaicin juzu'in juzu'i na sandar lattice mai tsini tare da kusurwoyin tantanin halitta daban-daban da kauri daga cikin jirgin.
Kauri daga cikin ainihin grating auxetic da yanayin yanayin (watau \(\theta=70^\circ\)) yana shafar matsakaicin matsawa na farantin sanwici (Hoto 6). Ana iya ganin cewa mafi girman jujjuyawar farantin yana ƙaruwa tare da ƙara h / l. Bugu da ƙari, haɓaka kauri na auxetic core yana rage porosity na tsarin concave, don haka ƙara ƙarfin lanƙwasa tsarin.
Matsakaicin jujjuyawar sandunan sanwici da ke haifar da sifofin lattice tare da ainihin auxetic na kauri da tsayi iri-iri.
Nazarin filayen damuwa yanki ne mai ban sha'awa wanda za'a iya bincika ta hanyar canza ma'auni na geometric na tantanin halitta don nazarin yanayin gazawa (misali, delamination) na tsarin multilayer. Matsakaicin Poisson yana da tasiri mafi girma akan filin da ba a cikin jirgin sama fiye da damuwa na al'ada (duba siffa 7). Bugu da ƙari, wannan tasirin ba shi da daidaituwa a cikin kwatance daban-daban saboda halayen orthotropic na kayan waɗannan gratings. Sauran sigogi na geometric, irin su kauri, tsayi, da tsayin sifofi masu rarrafe, ba su da tasiri a kan filin damuwa, don haka ba a bincika su a cikin wannan binciken ba.
Canji a cikin abubuwan damuwa mai ƙarfi a cikin yadudduka daban-daban na panel sandwich tare da filler ɗin lattice tare da kusurwoyi daban-daban.
Anan, ana bincika ƙarfin lanƙwasawa na farantin multilayer mai goyan bayan kyauta tare da madaidaicin lattice core ta amfani da ka'idar zigzag. An kwatanta tsarin da aka tsara tare da wasu ka'idoji na gargajiya, gami da ka'idar elasticity mai girma uku, ka'idar lalacewa ta farko, da FEM. Muna kuma inganta hanyarmu ta hanyar kwatanta sakamakonmu tare da sakamakon gwaji akan tsarin sanwici da aka buga na 3D. Sakamakonmu ya nuna cewa ka'idar zigzag tana iya yin hasashen lalacewar tsarin sanwici na matsakaicin kauri a ƙarƙashin nauyin lanƙwasa. Bugu da ƙari, an yi nazarin tasirin ma'auni na geometric na tsarin lattice na concave akan halin lanƙwasa na sandunan sanwici. Sakamakon ya nuna cewa yayin da matakin auxetic yana ƙaruwa (watau, θ <90), ƙarfin lanƙwasawa yana ƙaruwa. Bugu da ƙari, haɓaka yanayin yanayin da rage kauri na ainihin zai rage ƙarfin lanƙwasawa na sanwicin panel. A ƙarshe, ana nazarin tasirin ma'aunin Poisson akan damuwa da tsagewar jirgin sama, kuma an tabbatar da cewa rabon Poisson yana da tasiri mafi girma akan damuwa mai ƙarfi da ke haifar da kauri na farantin laminated. Ƙididdigar da aka tsara da ƙaddamarwa na iya buɗe hanya zuwa ƙira da ingantawa na multilayer Tsarin tare da concave lattice fillers a karkashin mafi hadaddun loading yanayi wajibi ne don ƙirƙira kayan aiki mai ɗaukar nauyi a cikin sararin samaniya da fasahar halittu.
Rubutun bayanan da aka yi amfani da su da/ko aka yi nazari a cikin binciken na yanzu suna samuwa daga mawallafa bisa ga buƙatu mai ma'ana.
Aktai L., Johnson AF, Kreplin B. Kh. Simulation na lamba na halayen lalata na saƙar zuma. injiniya. fractal. fur. 75 (9), 2616-2630 (2008).
Gibson LJ da Ashby MF Porous Solids: Tsarin da Kaddarorin (Jami'ar Cambridge, 1999).
Lokacin aikawa: Agusta-12-2023