Iziseko zobalo olungatshintshiyo
Ukhuni luyindalo yendalo kwaye, ngenxa yesakhiwo sayo se-anatomical, sisixhobo sokwakha esingenakulinganiswa. Inokuthi ifaniswe nenqwaba yeetyhubhu, ilungelelaniswe ngokulinganayo kunye ne-annular ejikeleze umbindi womthi - amakhonkco onyaka okanye amakhonkco - apho yonke indawo inamacandelo ahlukeneyo kunye nobukhulu bodonga, oko kukuthi iinkuni zangaphambili kunye nexesha elide.
Ukomelela komthi kuxhomekeke kwiimeko apho iinkuni zikhula phantsi kwazo, yaye ubukhulu becala zichatshazelwa ziphene zomthi, izitenxo kuphuhliso, ubudala bomthi ngexesha lokugawulwa nokusetyenziswa kwaye ngakumbi ukufuma kwawo.
Umlinganiselo wexabiso lamandla awohlukanga kuphela kwimithi eyodwa esuka kwindawo enye, kodwa nakuloo mthi mnye wehla ukusuka kowona mkhulu ukuya kweyona siphelo sincinci. Kwi-cross-section, amakhonkco amancinci onyaka phantsi kwe-bark amele ukhuni olungcono kunye nolunzima. Ingcaphephe yezamahlathi inokuphembelela iipropati zomthi kuphela kumda olinganiselweyo, ngelixa umsebenzisi engakwazi ukutshintsha iimpawu zamandla ngeendlela ezilula.
Amandla acinezelayo
Uxinzelelo kwicala lemicu
Xa uphonononga imizekelo yovavanyo, ubukhulu becala isikweri kwi-cross-section, ukungaphumeleli kwenzeka ngenxa yokuba iindonga zeseli zemicu zijija zibe yimingxuma, apho ngaphambili kuchazwe ngokucacileyo ukwandiswa okunqamlezileyo akunakumiselwa. Ukuqala kolu qhushululu lwenzeka kwiindawo ezinezitenxo ezincinci kulwakhiwo, apho kwiimeko ezininzi azinakubonwa nangaphandle, okanye ziqale ukusuka kumgangatho ophezulu okanye ophantsi ocinezelekileyo.
Uxinzelelo oluvumelekileyo lwemithi ye-coniferous - kungakhathaliseki ukuba i-spruce, ipineyini okanye i-fir - ibekwe kwi-8,5 MPa, kunye ne-larch wood kwi-9 MPa. Ngokhuni oluqinileyo, i-oki okanye ibhitshi, yi-10 MPa.
Ngokubanzi, olona phawu lokwenyani lwamandla oxinzelelo, ubuncinci be-oki, alukho phezulu kunelo lwe-conifers, kodwa eli xabiso lisanyanisekile kuba umthi onzima usetyenziswa kuphela kwiziqwenga ezincinci kulwakhiwo, ngoko ke iinkuni ezinamaqhina amakhulu okanye iinkuni ezinophuhliso olungaqhelekanga zinokuphetshwa. Umthi wom-oki ugqithise kakhulu. I-oki encinci, ukuya kuthi ga kwiminyaka 30 ubudala, ibonakala yomelele kwaye yomelele kunemithi yemithi emidala.
Iklasi yomgangatho ndivumela amandla omthi we-conifer ukuya kuthi ga ku-11 MPa, kwi-larch 11,5 MPa, kunye ne-oki kunye ne-beech 12 MPa. Amaxabiso e-6 MPa kwiplanga le-coniferous, kunye 7 MPa ye-oki kunye ne-beech zamiselwa umgangatho weklasi III.
Uxinzelelo lwependicular ukuya kwicala lefiber
Kwi-directional perpendicular to fibres, i-phenomena in failures ihluke kwizinto ezibangelwa ukunyanzeliswa kwengcinezelo kwi-fibers. Amandla phantsi koxinzelelo olunqamlezileyo kuxhomekeke ikakhulu kumandla abonakaliswe sisixa esingaxutywanga somthi wokuqala kwindandatho yonyaka. Umthi osemva kwexesha, apho ixabiso lamandla phantsi koxinzelelo lwe-axial lixhomekeke, phantsi koxinzelelo olunqamlezayo linendima yokusasazwa komthwalo.
Xa kuhlolwa isandla esibonisa ubukhulu bamandla, sihlala sigcina indawo yaso ephezulu. Kwimeko yecandelo elilayishwe ngokupheleleyo, amandla aphantsi koxinzelelo lwe-perpendicular perpendicular to the fibers for conifers imali1/7ukuya1/10amaxabiso omelela kwicala lemicu, kunye nomthi onzima ukusuka1/3ukuya1/5amaxabiso amandla kwicala lefiber.
Tensile strength
Amandla okuqina avavanywa kancinane kunamandla acinezelayo. Oku kusenokuba kungenxa yokuba ukuveliswa kunye novavanyo lweesampulu ezifanelekileyo zovavanyo kuthatha ixesha kwaye kuyabiza.
Ukungahambi kakuhle kwisakhiwo somthi kubonakala ngokubonakalayo kumandla obunzima. Ngokufana nokomelela phantsi koxinzelelo, ukongeza kububanzi bezigodo, ubungakanani bomthi osemva kwexesha bubaluleke kakhulu. Ukungaphumeleli kwemithi yokuqala kwenzeka ngaphambi kokungaphumeleli kwemithi kade, ngoko ke amandla omthi wokuqala kunye nasemva kwexesha akanakongezwa. Impembelelo yamaqhina kunye nezitenxo zophuhliso zibonakala ngakumbi kunamandla oxinzelelo. Nakuphi na ukugoba okanye i-wave ebangelwa ukusondela kwamaqhina, okungafunekiyo ukuba ibe yintonga, yanele ukunciphisa amandla okuqhekeza kwikota yamandla obunzima bomthi ngaphandle kweziphene.
Awona manqaku abuthathaka kwizinto ezixineneyo ziindawo zesakhiwo, apho ubuthathaka ngenxa yeenotshi zobuchopho bukhulu kakhulu. Apha, ngokukodwa ezihlathini, oko kukuthi i-garters, kukho uxinzelelo ngenxa yokugoba ukuba ukubala akubandakanyi.
Uxinzelelo oluvumelekileyo lwemithi ye-coniferous ukusuka kwiklasi esemgangathweni mna:10,5 MKulungile, kuthekani ngomthi wom-oki kunye ne-beech11 MKulungile. Kwizinto ezixinzelelekileyo, ukusetyenziswa kwezinto ezivela kwiklasi ye-III esemgangathweni akubandakanywa.
Isixhobo sokuvavanya ukomelela komthi.
Amandla okugoba
Iingqikelelo ezisisiseko sefomula yokubala Navier’s zisebenza ngokuqikelelwa okulungileyo kwiplanga ngokunjalo, kodwa kuphela kwimithwalo ephantsi. Kumthwalo ophezulu, ukufuduka okunjalo kwenzeka ukuba uxinzelelo lwangempela lwecala ngenxa yoxinzelelo luphantsi kunokuba lubalwe, ngelixa umfanekiso ochaseneyo ufunyenwe ngenxa yoxinzelelo ngenxa yoxinzelelo. Umgca onguziro wokwenyani ushukuma ukuya kwicala eliqinileyo.
Imifanekiso1kwaye2- Ukuqhekeka kwento kunye nokusabalalisa uxinzelelo ngexesha lokugoba.
Amandla okugoba abaliweyo ngexesha lekhefu mkhulu kuno1,4ukuya2amaxesha amandla okucinezela kwaye, ngaphandle kwezinto ezimbalwa, angaphantsi kwamandla okuqina. Ukuba amaqhina kunye nezitenxo zenzeka kufutshane nawona maxesha aphezulu kunye noxinzelelo oluphezulu, ukuncipha kwenzeka ukuya kuthi ga50%.
Kufuneka kugxininiswe ukuba amandla okugoba phantsi kokulayisha okusisigxina kwexesha elide malunga nesiqingatha samandla okugoba okugqitywe ngendlela eqhelekileyo. Ukuba umthwalo uphelele okanye inxalenye uphindwa ngokuphindaphindiweyo, umthamo womthwalo uya kuqhubeka unciphisa ngokuxhomekeke kubungakanani bomthwalo ohambayo oncedisayo kumthwalo opheleleyo.
Uxinzelelo lokugoba oluvumelekileyo lwe-softwood yomgangatho weklasi III ngu-7 MPa, kunye neeklasi ezisemgangathweni II kunye ne-I kumiselwa 10 MPa kunye 13 MPa, ngokulandelanayo. Ukufumana inkxaso eqhubekayo ngaphandle kwamalungu ukusuka kwiiklasi ezimbini zokugqibela, uxinzelelo lwe-11 MPa kunye 14 MPa lunikezelwe, kuba ezo nkxaso zibonisa ukhuseleko olukhulu.
Xa imiqadi yokulinganisa ibonakaliswe ekugobeni, kwiimeko ezininzi ayiloxinzelelo lokugoba olusetyenziswayo, kodwa ukuphambuka okuvumelekileyo. Kwimiqadi yezakhiwo ze-mezzanine, ukuphambuka ngenxa yomthwalo osisigxina okanye oluncedo akufunekanga udlule 1/300 uluhlu. Ngomqadi oxhaswa ngokukhululekileyo olayishwe ngomthwalo owabiwe ngokulinganayo, umlinganiselo phakathi kobude kunye nobude kufuneka bube bubuninzi be-16, kunye noxinzelelo oluvumelekileyo lokugoba lwe-10 MPa.
Kufutshane, imiqadi elayishwe kakhulu kunye namacandelo anqamlezayo, uxinzelelo lokucheba lubaluleke kakhulu. Imodyuli ye-elasticity ibalulekile ekuphambukeni, kunye nokomelela kwe-buckling kunye nokubalwa kolwakhiwo olungenammiselo. Ubungakanani bemodyuli ye-elasticity, kuxhomekeke kumgangatho wezinto eziphathekayo, iyahluka ngokubanzi. Imodyuli ye-elasticity ye-conifers yi-10.000 MPa, kwaye i-perpendicular to the fibers eli xabiso ngu-300 MPa ye-coniferous wood kunye 600 MPa ye-oki kunye ne-beech wood.
Isixhobo sokuvavanya ukugoba komthi.
Amandla okucheba
Xa uchetywa, umthi ubonisa amandla aphantsi. Amaxabiso okuqina okucheba anokwahluka kakhulu ngenxa yokuqhekeka komthi.
Umda ophezulu we-0,9 MPa usekwe kwi-softwood yazo zontathu iiklasi ezisemgangathweni. Kwimithi ye-oki kunye ne-beech yomgangatho we-II kunye ne-III, elona xabiso liphezulu ngu-1 MPa, ngokulandelelanayo 1,2 MPa yeklasi I.
Ukuba i-overhangs emfutshane kakhulu ifunyenwe kule mibhobho, kucetyiswa ukuba i-voltages ingasetyenziswa. Xa isiphelo se-overhangs sifutshane, kukho ingozi enkulu yokuqhekeka kweentanda ezenza inqwelomoya yokucheba, enokukhokelela kwilahleko epheleleyo yomthamo wokuthwala umthwalo.
Isixhobo sokuvavanya amandla okucheba iinkuni.
Amandla okubopha
Ukuba iintonga zibonakaliswe kuxinzelelo, kuyimfuneko ukujonga ukugoba ngokubala. Okubaluleke kakhulu kukhetho oluchanekileyo lobude bokugoba. Iintonga kufuneka zikhuselwe ngokudibanisa ngokuchasene nokuphambuka ngasecaleni. Ukuba oku akunakwenziwa ukusa kumkhamo owaneleyo, ubude bokugoba obukhulu kufuneka bufakwe ekubaleni.
Figures 3 kunye 4 - Amacandelo anqamlezayo agcweleyo kunye ahlanganisiweyo anezixhobo kunye neezembe ezingabonakaliyo.
Kwiintonga ezicinezelweyo ezintsonkothileyo, ubalo lwenziwa ngokunxulumene ne-axis yezinto, i-x-axis emifanekisweni.4kwaye nam4b, ngokufanayo kumacandelo apheleleyo, apho ububanzi bentonga yonke buthathwa njenge sumdi yobubanzi d bezinto ezizimeleyo.
Ukubopha ngokunxulumene ne-asis engabonakali, i-y-axis kwimifanekiso4kwaye,4b ndi4c kunye no-x-axis emfanekisweni4c, awukwazi ukubala kwindibaniselwano egqibeleleyo yamacandelo omnqamlezo ngamnye, kuba ukudityaniswa komnqamlezo weentonga zokhuni kuyavuna. Ngamacandelwana amabini anqamlezayo ngokomfanekiso4kunye nobudlelwane obulandelayo buyasebenza:
Iifomula zentsusa zokubalwa kwamacandelo amabini anqamlezayo.
Iirodi ezicinezelweyo zeCompound zisetyenziswa ngokubanzi kuphela apho udibaniso luyifuna, o.k.t. xa izinto zecandelo elipheleleyo kwimilinganiselo efunekayo zingenakufumaneka. Ukusondela kangangoko kunokwenzeka kumacandelo apheleleyo, uqhagamshelwano oluqhubekayo lwelongitudinal luhlala lucetyiswa.
Izihloko ezinxulumeneyo: ukuxhasa izakhiwo zomthi, ulwakhiwo oluphakathi kwemigangatho, iziphene zomthi, ukufuma kweenkuni kunye nesakhiwo.