Lokacin da Dokar Hooke ba ta isa ba ...

Bisa ga dokar Hooke da aka sani daga litattafan makaranta, tsayin daka na jiki ya kamata ya kasance daidai da matsananciyar damuwa. Koyaya, yawancin kayan da ke da mahimmanci a cikin fasahar zamani da rayuwar yau da kullun kawai suna bin wannan doka ne ko kuma suna nuna bambanci. Masana kimiyya da injiniyoyi sun ce irin waɗannan kayan suna da kaddarorin rheological. Nazarin waɗannan kaddarorin zai zama batun wasu gwaje-gwaje masu ban sha'awa.

Rheology shine nazarin kaddarorin kayan da halayensu ya wuce ka'idar elasticity bisa ka'idar Hooke da aka ambata a baya. Wannan hali yana da alaƙa da abubuwa masu ban sha'awa da yawa. Waɗannan sun haɗa da, musamman: jinkirin dawowar kayan zuwa matsayinsa na asali bayan raguwar ƙarfin lantarki, watau, hysteresis na roba; karuwa a elongation na jiki a cikin damuwa akai-akai, in ba haka ba ake kira kwarara; ko karuwa da yawa a cikin juriya ga nakasawa da taurin jikin filastik na farko, har zuwa bayyanar kaddarorin halayen gaggautsa kayan.

malalacin shugaba

Ɗayan ƙarshen mai mulki na filastik tare da tsawon 30 cm ko fiye yana gyarawa a cikin vise jaws don haka mai mulki ya kasance a tsaye (Fig. 1). Mun ƙi babban ƙarshen mai mulki daga tsaye ta 'yan milimita kawai kuma mu sake shi. Lura cewa ɓangaren kyauta na mai mulki yana motsawa sau da yawa a kusa da ma'auni na tsaye kuma ya dawo zuwa asalinsa (Fig. 1a). Ƙwaƙwalwar da aka lura sun dace da juna, tun da a ƙananan ɓangarorin girman girman ƙarfin da ke aiki a matsayin ƙarfin jagora yana daidai da karkatar da ƙarshen mai mulki. An kwatanta wannan hali na mai mulki ta hanyar ka'idar elasticity. 

Shinkafa 1. Nazari na roba hysteresis ta amfani da mai mulki

1- shugaba,

2 - vise jaws, A - karkatar da ƙarshen mai mulki daga tsaye

A cikin kashi na biyu na gwajin, muna karkatar da ƙarshen mai mulki ta 'yan santimita kaɗan, sake shi, kuma mu lura da halayensa (Fig. 1b). Yanzu wannan ƙarshen yana dawowa sannu a hankali zuwa matsayin daidaito. Wannan shi ne saboda wuce haddi na iyakoki na roba na kayan mulki. Ana kiran wannan tasirin na roba hysteresis. Ya ƙunshi a sannu a hankali dawo da gurɓataccen jiki zuwa yanayinsa na asali. Idan muka sake maimaita wannan gwaji na ƙarshe ta hanyar karkatar da ƙarshen mai mulki fiye da haka, za mu ga cewa dawowar shi ma zai kasance a hankali kuma yana iya ɗaukar mintuna kaɗan. Bugu da ƙari, mai mulki ba zai dawo daidai zuwa matsayi na tsaye ba kuma zai ci gaba da lankwasa har abada. Tasirin da aka bayyana a kashi na biyu na gwajin daya ne kawai batutuwan bincike na rheology.

Komawa tsuntsu ko gizo-gizo

Don ƙwarewa ta gaba, za mu yi amfani da arha kuma mai sauƙi don siyan kayan wasan yara (wani lokacin ma ana samun su a kiosks). Ya ƙunshi nau'i mai laushi a cikin nau'i na tsuntsu ko wata dabba, irin su gizo-gizo, wanda aka haɗa da dogon madauri tare da nau'i mai siffar zobe (Fig. 2a). Dukkanin wasan wasan an yi shi ne da wani abu mai juriya, kamar roba wanda ke dan manne da tabawa. Ana iya shimfiɗa tef ɗin cikin sauƙi, ƙara tsawonsa sau da yawa ba tare da yage shi ba. Muna gudanar da gwaji kusa da wuri mai santsi, kamar gilashin madubi ko bangon kayan ɗaki. Tare da yatsun hannu ɗaya, riƙe hannun kuma yi tagumi, ta yadda za a jefa abin wasan yara kan wani wuri mai santsi. Za ku lura cewa figurine ɗin yana manne a saman kuma tef ɗin yana tsayawa. Muna ci gaba da riƙe hannun tare da yatsunmu na daƙiƙa da yawa ko fiye.

Shinkafa 2. Kyakkyawan misali na ƙawancen ɗabi'a, wanda aka nuna ta amfani da giciye mai dawowa

1 - gizo-gizo figurine, 2 - roba band;

3 - rike, 4 - dabino, 5 - saman

Bayan wani lokaci, mun lura cewa figurine zai fito da sauri daga saman kuma, yana jan hankalin tef ɗin zafi, zai dawo hannunmu da sauri. A wannan yanayin, kamar yadda a cikin gwajin da ya gabata, akwai kuma jinkirin lalata wutar lantarki, watau, hysteresis na roba. Ƙungiyoyin na roba na tef ɗin da aka shimfiɗa sun shawo kan ƙarfin mannewa na ƙirar zuwa saman, wanda ya raunana a tsawon lokaci. A sakamakon haka, adadi ya koma hannun. Abubuwan kayan wasan yara da aka yi amfani da su a cikin wannan gwaji ana kiran su ta hanyar masu ilimin rheologist viscoelastic. Wannan suna ya tabbata ne ta yadda ya ke baje kolin abubuwa guda biyu masu danko – idan ya manne a kan shimfida mai santsi, da na roba – wanda a dalilin haka ya watse daga wannan saman ya koma yadda yake.

mutum mai saukowa

Hoto na 1. Hoton siffar da ke saukowa bangon tsaye shima babban misali ne na jijiyar roba.

Wannan gwajin kuma zai yi amfani da kayan wasan yara da aka yi da kayan viscoelastic (hoto 1). An yi shi a cikin siffar mutum ko gizo-gizo. Muna jefa wannan abin wasan wasa tare da tura gaɓoɓi kuma muna juyewa a kan wani fili mai faɗin tsaye, zai fi dacewa akan gilashi, madubi ko bangon kayan ɗaki. Wani abu da aka jefa yana manne da wannan saman. Bayan wani lokaci, tsawon lokacin da ya dogara, a tsakanin sauran abubuwa, a kan rashin ƙarfi na saman da kuma saurin jefawa, saman abin wasan yara ya fito. Hakan na faruwa ne sakamakon abin da aka tattauna a baya. na roba hysteresis da kuma aikin nauyin nauyin adadi, wanda ya maye gurbin ƙarfin roba na bel, wanda ya kasance a cikin gwajin da ya gabata.

Ƙarƙashin tasirin nauyi, ɓangaren abin wasan wasan da ya keɓe ya lanƙwasa ya kara lalacewa har sai sashin ya sake taɓa saman tsaye. Bayan wannan tabawa, gluing na gaba na adadi zuwa saman yana farawa. A sakamakon haka, za a sake manne adadi, amma a cikin matsayi na ƙasa. Hanyoyin da aka bayyana a ƙasa ana maimaita su, tare da alkaluman da ke yayyage kafafu sannan kuma kai. Tasirin shine adadi yana saukowa tare da saman tsaye, yana yin juzu'i na ban mamaki.

Ruwan filastik

Shinkafa 3. Gwajin kwararar filastik

a) Halin farko, b) yanayi na ƙarshe;

1 - dabino, 2 - babban ɓangaren filastik.

3 - mai nuna alama, 4 - ƙuntatawa, 5 - tsagewar yanki na filastik

A cikin wannan da kuma gwaje-gwajen da yawa na gaba, za mu yi amfani da filastik da ake samu a cikin shagunan wasan yara, wanda aka sani da "laka mai sihiri" ko "tricolin". Muna durƙusa wani yanki na filastik a cikin siffar kama da dumbbell, kimanin 4 cm tsayi kuma tare da diamita na sassa masu kauri a cikin 1-2 cm da kunkuntar diamita na kimanin 5 mm (Fig. 3a). Muna ɗaukar gyare-gyaren tare da yatsun mu ta ƙarshen babba na ɓangaren kauri kuma mu riƙe shi ba motsi ko rataye shi a tsaye kusa da alamar da aka shigar yana nuna wurin ƙananan ƙarshen ɓangaren mafi kauri.

Lura da matsayi na ƙananan ƙarshen filastik, mun lura cewa yana raguwa a hankali. A wannan yanayin, tsakiyar ɓangaren filastik yana matsawa. Ana kiran wannan tsari mai gudana ko rarrafe na kayan kuma ya ƙunshi ƙara haɓakarsa a ƙarƙashin aikin damuwa na dindindin. A cikin yanayinmu, wannan damuwa yana haifar da nauyin ƙananan ɓangaren dumbbell na filastik (Fig. 3b). Daga mahangar ra'ayi na yanzu wannan shi ne sakamakon canji a cikin tsarin kayan da aka yi wa lodi na dogon lokaci. A wani lokaci, ƙarfin ɓangaren kunkuntar yana da ƙanƙanta har ya karye a ƙarƙashin nauyin ƙananan ɓangaren filastik kawai. Yawan kwarara ya dogara da dalilai da yawa, gami da nau'in kayan, adadin da kuma hanyar amfani da damuwa zuwa gare shi.

Plasticine da muke amfani da shi yana da matukar damuwa ga kwarara, kuma muna iya ganinsa da ido tsirara a cikin 'yan daƙiƙa kaɗan. Yana da kyau a kara da cewa, wani yumbun sihiri ne aka kirkiro ta hanyar haɗari a Amurka, a lokacin yakin duniya na biyu, lokacin da aka yi ƙoƙari na samar da wani abu na roba wanda ya dace da kera tayoyin motocin soja. Sakamakon rashin cikar polymerization, an samo wani abu wanda wasu adadin kwayoyin halitta ba su da iyaka, kuma haɗin kai tsakanin sauran kwayoyin halitta zai iya canza matsayi a cikin sauƙi a ƙarƙashin rinjayar abubuwan waje. Waɗannan hanyoyin haɗin "bouncing" suna ba da gudummawa ga abubuwan ban mamaki na bouncing yumbu.

ball bata

Shinkafa 4. Saita don gwada filastik don yadawa da shakatawa na damuwa:

a) Halin farko, b) yanayi na ƙarshe; 1- Ballon karfe,

2 - jirgin ruwa m, 3 - filastik, 4 - tushe

Yanzu matse sihirin filastik a cikin ƙaramin jirgin ruwa mai haske, buɗe a saman, tabbatar da cewa babu kumfa mai iska a ciki (Fig. 4a). Tsayi da diamita na jirgin ya kamata ya zama santimita da yawa. Sanya ƙwallon karfe kamar 1,5 cm a diamita a tsakiyar saman saman filastik. Mun bar jirgin ruwa tare da kwallon kadai. Kowane sa'o'i kadan muna lura da matsayin kwallon. Yi la'akari da cewa yana zurfi da zurfi a cikin filastik, wanda, bi da bi, yana shiga cikin sararin samaniya a saman saman ƙwallon.

Bayan isasshen lokaci mai tsawo, wanda ya dogara da: nauyin ball, nau'in filastik da aka yi amfani da shi, girman ball da kwanon rufi, yanayin zafi, mun lura cewa ƙwallon ya kai kasan kwanon rufi. Wurin da ke sama da ƙwallon zai cika da filastik (Fig. 4b). Wannan gwaji ya nuna cewa kayan yana gudana da rage damuwa.

Tsalle filastik

Ƙirƙiri ƙwallon ƙwallon sihiri kuma da sauri jefa shi kan wani wuri mai wuya kamar ƙasa ko bango. Mun lura da mamaki cewa filastik yana billa daga waɗannan saman kamar ƙwallon roba na bouncy. Lambun sihiri jiki ne wanda zai iya nuna kayan filastik da na roba. Ya dogara da yadda sauri kayan zai yi aiki da shi.

Lokacin da aka yi amfani da damuwa a hankali, kamar yadda yake a cikin kullun, yana nuna kayan filastik. A gefe guda, lokacin da aka yi amfani da karfi da sauri, wanda ke faruwa a lokacin da ya yi karo da bene ko bango, filastik yana nuna halayen roba. Ana iya kiran yumbun sihiri a taƙaice jikin filastik-lastic.

Plasticine tensile

Hoto 2. Sakamakon jinkirin shimfiɗar yumbu na sihiri (tsawon fiber mai shimfiɗa yana kusan 60 cm)

A wannan lokacin, samar da silinda mai sihiri na filastik kamar 1 cm a diamita da tsayin ƴan santimita. Ɗauki ƙarshen duka biyu tare da yatsun hannun dama da hagu kuma saita abin nadi a kwance. Sa'an nan kuma sannu a hankali mu shimfiɗa hannayenmu zuwa tarnaƙi a cikin layi daya madaidaiciya, ta haka ne ya sa silinda ya shimfiɗa a cikin axial direction. Muna jin cewa filastik yana ba da kusan babu juriya, kuma mun lura cewa yana raguwa a tsakiya.

Ana iya ƙara tsawon silinda na filastik zuwa dubun santimita da yawa, har sai an kafa zaren bakin ciki a tsakiyar sa, wanda zai karye a kan lokaci (hoto 2). Wannan gwaninta ya nuna cewa ta hanyar yin amfani da damuwa a hankali zuwa jikin filastik-lastic, mutum na iya haifar da nakasa mai girma sosai ba tare da lalata shi ba.

filastik mai wuya

Muna shirya silinda mai sihirin filastik kamar yadda aka yi a gwajin da ya gabata kuma muna nannade yatsunmu a kusa da ƙarshensa kamar yadda yake. Bayan tattara hankalinmu, mun shimfiɗa hannayenmu zuwa tarnaƙi da sauri, muna so mu shimfiɗa silinda sosai. Sai dai itace cewa a cikin wannan harka muna jin wani sosai high juriya na plasticine, da kuma Silinda, abin mamaki, ba elongate ko kadan, amma karya a cikin rabin da tsawon, kamar dai yanke da wuka (photo 3). Har ila yau, wannan gwaji ya nuna cewa yanayin nakasar jikin filastik-roba ya dogara da ƙimar aikace-aikacen damuwa.

Plasticine yana da rauni kamar gilashi

Hoto 3. Sakamakon saurin mikewar sihirin filastik - zaku iya ganin sau da yawa ƙarancin elongation da kaifi mai kaifi, kama da fashe a cikin wani abu mai rauni.

Wannan gwaji yana nuna ƙarara sosai yadda ƙimar damuwa ke shafar kaddarorin jikin filastik-na roba. Ƙirƙirar ball mai diamita na kusan 1,5 cm daga yumbu mai sihiri kuma sanya shi a kan wani ƙaƙƙarfan tushe mai ƙaƙƙarfan tushe, kamar farantin karfe mai nauyi, majiya, ko bene na kankare. A hankali buga ƙwallon da guduma mai nauyin aƙalla kilogiram 0,5 (Hoto 5a). Sai ya zama cewa a cikin wannan hali, ƙwallon yana zama kamar jikin filastik kuma yana bajewa bayan guduma ya faɗo a kanta (Fig. 5b).

Ƙirƙiri fiɗaɗɗen filastik a cikin ƙwallon kuma a sanya shi a kan farantin karfe kamar da. Sake buga kwallon da guduma, amma wannan lokacin muna ƙoƙarin yin shi da sauri (Fig. 5c). Ya bayyana cewa ƙwallon filastik a cikin wannan yanayin yana nuna kamar an yi shi da wani abu mai rauni, kamar gilashi ko ain, kuma a kan tasiri ya rushe guntu a kowane bangare (Fig. 5d).

Injin thermal akan madaurin roba na magunguna

Ana iya rage damuwa a cikin kayan aikin rheological ta hanyar haɓaka yanayin su. Za mu yi amfani da wannan tasiri a cikin injin zafi tare da ka'idar aiki mai ban mamaki. Don haɗa shi, za ku buƙaci: hular gwangwani mai dunƙule gwangwani, dozin ko gajerun igiyoyi na roba, babban allura, ƙaramin ƙarfe na bakin ciki mai siffar rectangular, da fitila mai fitila mai zafi sosai. An nuna ƙirar motar a cikin siffa 6. Don tara shi, yanke tsakiyar tsakiya daga murfin don samun zobe.

Shinkafa 5. Hanya don nuna filastik da kuma ɓarna Properties na filastik

a) jinkirin bugun ƙwallon b) jinkirin bugawa

c) bugu da sauri akan ball, d) tasirin bugun da sauri;

1 - ball na filastik, 2 - m da babban faranti, 3 - guduma,

v - gudun guduma

A tsakiyar wannan zobe mun sanya allura, wanda shine axis, kuma mun sanya igiyoyi na roba akan shi don haka a tsakiyar tsayinsa sun tsaya a kan zobe kuma suna da karfi sosai. Ya kamata a sanya maƙallan roba daidai gwargwado akan zobe, don haka, ana samun dabaran tare da magana da aka kafa daga maƙallan roba. Lanƙwasa wani ɗan ƙaramin takarda ya zama siffa mai ɗaci tare da shimfiɗa hannuwanku, yana ba ku damar sanya da'irar da aka yi a baya a tsakanin su kuma rufe rabin samansa. A gefe ɗaya na cantilever, a duka gefuna na tsaye, muna yin yanke wanda zai ba mu damar sanya ƙafar ƙafar a cikinsa.

Sanya axle dabaran a cikin yanke goyan baya. Muna juya dabaran da yatsun mu kuma mu duba idan yana da daidaito, watau. shin yana tsayawa a kowane matsayi. Idan ba haka lamarin yake ba, daidaita dabaran ta dan matsawa wurin da igiyoyin roba suka hadu da zoben. Sanya madaidaicin akan teburin kuma haskaka sashin da'irar da ke fitowa daga bakunanta da fitila mai zafi sosai. Ya bayyana cewa bayan wani lokaci dabaran ta fara juyawa.

Dalilin wannan motsi shine canji na yau da kullun a matsayin tsakiyar taro na dabaran sakamakon wani tasiri da ake kira rheologists. thermal danniya shakatawa.

Wannan annashuwa yana dogara ne akan gaskiyar cewa wani abu mai mahimmanci na roba yana yin kwangila lokacin zafi. A cikin injin mu, wannan abu shine igiyoyin roba na gefen dabaran da ke fitowa daga madaidaicin sashi kuma suna dumama da kwan fitila. A sakamakon haka, tsakiyar taro na dabaran yana motsawa zuwa gefen da aka rufe da makamai masu tallafi. Sakamakon jujjuyawar dabaran, igiyoyin roba masu zafi sun faɗi tsakanin hannayen tallafi kuma suna kwantar da hankali, tunda a can suna ɓoye daga kwan fitila. Sanyi masu gogewa suna sake tsawaitawa. Jerin hanyoyin da aka kwatanta suna tabbatar da ci gaba da juyawa na dabaran.

Ba kawai na ban mamaki gwaje-gwaje

Shinkafa 6. Tsarin injin zafi wanda aka yi da igiyoyin roba na magunguna

a) kallon gefe

b) sashe ta jirgin saman axial; 1 - zobe, 2 - allura, 3 - gogewar magunguna,

4- Baki, 5- Yankewa a cikin sashin, 6- kwan fitila

Yanzu rheology yanki ne mai tasowa cikin sauri na sha'awar masana kimiyyar lissafi da kwararru a fagen ilimin fasaha. Abubuwan al'ajabi na rheological a wasu yanayi na iya yin mummunan tasiri a kan yanayin da suke faruwa kuma dole ne a yi la'akari da su, alal misali, lokacin zayyana manyan sifofin ƙarfe waɗanda ke lalacewa cikin lokaci. Suna tasowa ne sakamakon yaduwar kayan aiki a ƙarƙashin aikin aiki da nauyin nauyinsa.

Daidaitaccen ma'auni na kauri na zanen tagulla da ke rufe rufin tudu da tagogin gilashi a cikin majami'u masu tarihi sun nuna cewa waɗannan abubuwan sun fi na sama kauri a ƙasa. Wannan shi ne sakamakon na yanzuda jan karfe da gilashin da ke ƙarƙashin nauyin nasu shekaru ɗari da yawa. Hakanan ana amfani da abubuwan mamaki na rheological a yawancin fasahohin masana'antu na zamani da na tattalin arziki. Misali shine sake yin amfani da robobi. Yawancin samfuran da aka yi daga waɗannan kayan a halin yanzu ana kera su ta hanyar extrusion, zane da gyare-gyare. Ana yin hakan ne bayan dumama kayan da kuma amfani da matsi a kan ƙimar da aka zaɓa daidai. Don haka, a tsakanin sauran abubuwa, foils, sanduna, bututu, zaruruwa, da kuma kayan wasan yara da na'ura tare da sifofi masu rikitarwa. Muhimman fa'idodi na waɗannan hanyoyin sune ƙarancin farashi da rashin sharar gida.