Kera Ƙari (AM), musamman dabarun Narkar da Gadon Foda (PBF) kamar Sintering na Laser na Zaɓi (SLS), sun canza daga kayan aikin samfurin zuwa hanya mai inganci na samar da sassa masu sarkakiya da daraja. Kalubale mai mahimmanci a cikin SLS na kayan da ke da ramuka, kamar waɗanda ake amfani da su don ginshiƙan ilimin halittu ko tsarin daraja na aiki, shine haɓakar matsin baya da nau'in filastik a ma'aunin foda. Waɗannan bambance-bambancen tsaka-tsaki, waɗanda suka taso daga dumama na gida, narkewa cikin sauri, da haɗuwar tsakanin yadudduka, suna tasiri sosai ga ingancin injiniya na sashi na ƙarshe, daidaiton girma, da aikin dogon lokaci. Wannan aikin yana gabatar da sabon tsarin simfirin yanayin yanayi na Layer 3D wanda ya haɗa ƙirar lokaci-lokaci mara daidaiton zafi tare da binciken zafi-elasto-filastik don yin hasashe da bincika waɗannan abubuwan cikin cikakken bayani da ba a taɓa gani ba.
Tsarin da aka gabatar hanya ce ta haɗin gwiwa mai ƙarfi da aka tsara don ɗaukar hadaddun hulɗar yayin SLS.
Tsarin yana haɗa simfirin lokaci-lokaci mara daidaiton zafi wanda ya dogara da Hanyar Ƙididdiga ta Ƙarshe (FEM) don juyin halittar tsarin micro tare da binciken matsin zafi-elasto-filastik na gaba. Sakamako (filin zafin jiki, rarraba lokaci) daga mataki na farko yana aiki azaman shigarwa da ƙarfin tuƙi na na biyu. Wannan yana ba da damar ƙirar kaddarorin kayan da suka dogara da zafin jiki da lokaci da gaske.
Tsarin lokaci-lokaci mai yawan umarni yana bin iyakar ruwa-da-ƙarfe da haɗuwar ɓangarorin foda a ƙarƙashin tushen zafin Laser mai motsi. Juyin halitta yana ƙarƙashin tsarin lissafin Ginzburg-Landau, yana la'akari da matakan zafi da ƙarfin capillary.
Binciken matsin yana amfani da ƙirar filastik J2 tare da tauraro mai daidaitawa. Halayen kayan an ayyana shi ta hanyar modulus na Matashi mai dogaro da zafin jiki $E(T)$, ƙarfin yawan amfanin ƙasa $\sigma_y(T)$, da ma'aunin faɗaɗawar zafi $\alpha(T)$. Jimlar ƙimar nau'in $\dot{\epsilon}$ an raba shi zuwa sassan roba, filastik, da na zafi: $\dot{\epsilon} = \dot{\epsilon}^{e} + \dot{\epsilon}^{p} + \dot{\epsilon}^{th}$.
Simfirin sun bayyana yadda ƙarfin katako da saurin bincike ke sarrafa girma wuyan tsakanin ɓangarorin, yana ƙayyadad da ramuka na ƙarshe kai tsaye. An kafa alaƙar al'amari tsakanin yawan ƙarfin makamashi ($E_v = P/(v \cdot d \cdot h)$, inda $P$ shine ƙarfi, $v$ sauri, $d$ diamita na tabo, $h$ tazarar ƙyanƙyashe) da yawan dangi, yana nuna yanayin ƙara yawan ƙima tare da mafi girma $E_v$, daidai da abubuwan lura na gwaji a cikin wallafe-wallafe.
Babban binciken shine gano masu tattara matsin lamba mai mahimmanci: (1) yankunan wuyan hannu na ɓangarorin da aka narke a wani ɓangare, da (2) mahadar tsakanin yadudduka da aka ajiye a jere. Waɗannan yankuna suna aiki azaman wurare masu zafi don tarin nau'in filastik. Filin matsin baya yana da bambanci sosai, tare da matsin lamba sau da yawa ana samunsa a cikin tsakiyar wuyan hannun da aka yi da sinter da matsin lamba a cikin yankuna masu sanyi na kewaye.
Bayanin Chati (Simfirin): Zane-zanen 3D zai nuna tsarin lattice mai ramuka. Wuyan hannun ɓangarorin da iyakokin tsakanin yadudduka an haskaka su da ja/lemu, suna nuna babban matsin von Mises ko girman nau'in filastik. Cikin manyan ramuka da mahadar ƙasa za su bayyana a cikin shuɗi/kore, suna nuna ƙananan matakan matsin lamba. Yankunan yanki na giciye zai nuna matakin matsin lamba daga yanki na sama mai zafi zuwa na ƙasa mai sanyi.
Mafi girman ƙarfin katako a sauri mai dorewa yana ƙara girman tafkin narkewa da matakan zafi, yana haifar da mafi girman yanayin zafi da matsanancin matsin baya. Akasin haka, saurin bincike mai yawa sosai na iya haifar da rashin isasshen narkewa da haɗin gwiwa mara kyau, amma kuma yana rage zagayowar zafi kuma yana iya rage matsin baya. Binciken ya ba da shawarar ƙirar koma baya masu haɗa $E_v$ zuwa matsakaicin matsin baya da nau'in filastik, yana ba da alaƙar tsari-tsari-kaddarorin ƙididdiga.
Juyin halittar lokaci-filin don sigar umarni $\phi$ wanda ke wakiltar yanki mai ƙarfi an ba shi ta hanyar lissafin Allen-Cahn: $$\frac{\partial \phi}{\partial t} = -L \frac{\delta F}{\delta \phi}$$ inda $L$ shine ma'aunin motsi kuma $F$ shine jimlar aikin makamashi kyauta wanda ya haɗa da makamashi mai gradient, ƙarfin riko biyu, da zafi mai ɓoye. Binciken zafi-elasto-filastik yana warware lissafin daidaito: $$\nabla \cdot \boldsymbol{\sigma} + \mathbf{b} = 0$$ tare da $\boldsymbol{\sigma}$ a matsayin tensor na matsin Cauchy da $\mathbf{b}$ a matsayin ƙarfin jiki. Kwararar filastik yana bin ka'idar haɗin gwiwa $\dot{\epsilon}^{p} = \dot{\lambda} \frac{\partial f}{\partial \sigma}$, inda $f$ shine aikin yawan amfanin ƙasa $f = \sigma_{eq} - \sigma_y(T, \epsilon^{p}) \le 0$.
Binciken ya kwatanta yanayin ramuka da aka yi hasashen simfiri da yanayin ƙarfin makamashi tare da bayanan gwaji daga SLS na tsarin foda na polymer ko ƙarfe (bisa ga wallafe-wallafe). Yarjejeniyar gabaɗaya tana tabbatar da ikon ƙirar don ɗaukar injiniyoyin ƙima. Tabbatarwar ƙididdiga na filayen matsin baya da aka yi hasashen yawanci zai buƙaci bambance-bambancen hasken X-ray na synchrotron ko ma'aunin kwane-kwane akan samfuran da aka gina na musamman, wanda aka ba da shawarar a matsayin aikin gaba mai mahimmanci.
Yanayi: Haɓaka tsarin SLS don dasa kashin baya na titanium tare da sararin samaniya mai sarrafawa don shigar da ƙashi.
Aiwatar da Tsarin:
Fahimta ta Asali
Wannan takarda tana ba da gaskiya mai mahimmanci, wacce ake yawan yin watsi da ita: a cikin SLS mai ramuka, babban abin da ke haifar da gazawa ba shine babban kayan ba, amma tsarin micro-gine-gine. Simfirin yana haskaka kyakkyawan yadda matsin lamba da filastik ba a rarraba su daidai ba amma an tattara su cikin dabara (kuma cikin matsala) a ainihin sifofin da ke ayyana ramuka—wuyan hannun tsakanin ɓangarorin da mahadar yadudduka. Wannan yana juyar da binciken matsin lamba na "kayan da suka cika" na al'ada a kai.
Kwararar Hankali
Hankalin marubutan yana da ƙarfi: 1) Ƙirar tushen zafi da bin canjin lokaci (Lokaci-Filin). 2) Yi amfani da tarihin zafin don tuƙi nakasar injiniya (FEM). 3) Gano inda filastik ta fara da kulle a matsayin matsin baya. 4) Haɗa waɗannan binciken tsaka-tsaki tare da shigarwar tsarin macroscopic (Ƙarfi, Sauri). Haɗin gwiwa ne na ma'auni daban-daban, an aiwatar da shi tare da babban aminci don matsalar ramuka na SLS.
Ƙarfi & Kurakurai
Ƙarfi: Hanyar haɗin lokaci-filin-injiniya ita ce mafi zamani kuma ta dace daidai da matsalar. Gano yankunan wuyan hannu a matsayin masu tattara matsin lamba bincike ne mai mahimmanci, mai yiwuwa. Ƙoƙarin ƙirar ƙirar koma baya don sarrafa tsari yana da amfani sosai.
Kurakurai: Giwa a cikin ɗaki shine sauƙin ƙirar kayan. Yin amfani da daidaitaccen ƙirar filastik J2 yana yin watsi da hadaddun halayen foda da aka yi da sinter a rabin, wanda zai iya haɗawa da rarrafe da sassauci mai dogaro da lokaci yayin aikin da kansa. Bugu da ƙari, yayin da tsarin yana da ban sha'awa, tsadar lissafinsa yana iyakance shi ga ƙananan sassan wakilci na ƙima, ba hasashen sashi cikakke ba—gibi wanda wakilan koyon inji, waɗanda aka yi wahayi ta ayyuka kamar na CycleGAN don canja wurin salo a cikin simfirin da aka yi da hoto, zai iya cika a ƙarshe.
Fahimta Mai Aiki
Ga injiniyoyin tsari: Mayar da hankali kan mahadar tsakanin yadudduka da tsakanin ɓangarorin. Dole ne a tsara magungunan bayan aiki (misali, dumama zafi) don kaiwa ga waɗannan takamaiman yankuna masu matsin lamba, ba kawai duka sashi ba. Ga masu ƙira: Simfirin yana ba da taswira don kaucewa yanayin matsin lamba mai mahimmanci. Lokacin ƙirar tsarin lattice, mutum na iya canza sifofin kumburi ko yadudduka bisa ga waɗannan taswirorin matsin lamba. Ƙirar koma baya tana ba da kayan aiki na farko don zaɓin sigogi don rage matsin baya ga ramuka da aka yi niyya.