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| (23 גרסאות ביניים של אותו משתמש אינן מוצגות) |
| שורה 8: |
שורה 8: |
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| − | | + | ==טבלת השוואה בין חומרים שונים== |
| − | The '''specific strength''' is a material's [[Strength of materials|strength (force per unit area at failure)]] divided by its [[density]]. It is also known as the '''strength-to-weight ratio''' or '''strength/weight ratio''' or '''strength-to-mass ratio'''. In fiber or textile applications, [[Tenacity (textile strength)|tenacity]] is the usual measure of specific strength. The SI unit for specific strength is [[Pascal (unit)|Pa]] [[metre|m]]<sup>3</sup>/[[kilogram|kg]], or [[Newton (unit)|N]]·m/kg, which is [[Dimensional analysis|dimensionally equivalent]] to m<sup>2</sup>/s<sup>2</sup>, though the latter form is rarely used.
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| − | Another way to describe specific strength is '''breaking length''', also known as '''self support length''': the maximum length of a vertical column of the material (assuming a fixed cross-section) that could suspend its own weight when supported only at the top. For this measurement, the definition of [[weight]] is the force of [[gravity]] at the Earth's surface ([[standard gravity]], 9.80665 m/s<sup>2</sup>) applying to the entire length of the material, not diminishing with height. This usage is more common with certain specialty fiber or textile applications.
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| − | The materials with the highest specific strengths are typically fibers such as [[carbon fiber]], [[glass fiber]] and various polymers, and these are frequently used to make [[composite material]]s (e.g. [[Carbon fiber-reinforced polymer|carbon fiber-epoxy]]). These materials and others such as [[titanium]], [[aluminium]], [[magnesium]] and high strength steel alloys are widely used in [[aerospace]] and other applications where weight savings are worth the higher material cost.
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| − | Note that strength and stiffness are distinct. Both are important in design of efficient and safe structures.
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| − | | |
| − | ==Examples== | |
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| | {| class="wikitable sortable" style="text-align:right" style="margin: 1em auto 1em auto" | | {| class="wikitable sortable" style="text-align:right" style="margin: 1em auto 1em auto" |
| − | |+ Specific tensile strength of various materials | + | |+ יחס חוזק/משקל של חומרים שונים |
| − | ! Material !! data-sort-type="number" | [[Tensile strength]] <br /> ([[Megapascal|MPa]])!! data-sort-type="number" |[[Density]] <br /> ([[Gram|g]]/[[Cubic centimetre|cm³]])!! data-sort-type="number" | Specific strength<br /> ([[Kilonewton|kN]]·[[Metre|m]]/[[Kilogram|kg]]) !! data-sort-type="number" |Breaking length <br />([[Kilometre|km]]) !! Source | + | ! Material !! data-sort-type="number" | [[חוזק לקריעה]] <br /> (MPa)!! data-sort-type="number" |[[Density]] <br /> (g/cm³)!! data-sort-type="number" | יחס חוזק/משקל<br /> (kN·m/kg) !! data-sort-type="number" |אורך הנשיאה העצמי <br />(km) !! Source |
| − | |- align="right"
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| − | | align="left"| [[Concrete]] || 2–5 || 2.30 || 5.22 || 0.44 ||
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| − | |- align="right"
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| − | | align="left"| [[Rubber]] || 15 || 0.92 || 16.3 || 1.66 ||
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| − | |- align="right"
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| − | | align="left"| [[Copper]] || 220 || 8.92 || 24.7 || 2.51 ||
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| − | |- align="right"
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| − | | align="left"| [[Polypropylene]] / PP || 25–40 || 0.90 || 28–44 || 2.8–4.5 || <ref>http://www.goodfellow.com/E/Polypropylene.html</ref>
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| − | |- align="right"
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| − | | align="left"| (Poly)[[acrylonitrile-butadiene-styrene]] / ABS || 41–45 || 1.05 || 39–43 || || <ref>http://www.goodfellow.com/E/Polyacrylonitrile-butadiene-styrene.html</ref>
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| − | |- align="right"
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| − | | align="left"| [[Polyethylene terephthalate]] / Polyester / PET || 80 || 1.3–1.4 || 57–62 || || <ref>http://www.goodfellow.com/E/Polyethylene-terephthalate.html</ref>
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| − | |- align="right"
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| − | | align="left"| [[Piano wire]] / ASTM 228 Steel || 1590-3340 || 7.8 || 204-428 || || <ref>http://www.matweb.com/search/datasheet_print.aspx?matguid=4bcaab41d4eb43b3824d9de31c2c6849</ref>
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| − | |- align="right"
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| − | | align="left"| [[Polylactic acid]] / Polylactide / PLA || 53 || 1.24 || 43 || || <ref>http://www.goodfellow.com/E/Polylactic-acid-Biopolymer.html</ref>
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| − | |- align="right"
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| − | | align="left"| [[Carbon Steel|Low Carbon Steel]] (AISI 1010) || 365 || 7.87 || 46.4 || 4.73 || <ref>{{Cite web|title = AISI 1010 Steel, cold drawn |url = http://www.matweb.com/search/datasheetText.aspx?bassnum=M1010A | website = matweb.com|accessdate = 2015-10-20}}</ref>
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| − | |- align="right"
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| − | | align="left"| [[Stainless steel]] (304) ||505 || 8.00 || 63.1 || 6.4 || <ref>{{Cite web|title = ASM Material Data Sheet|url = http://asm.matweb.com/search/SpecificMaterial.asp?bassnum=MQ304A|website = asm.matweb.com|accessdate = 2015-10-20}}</ref>
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| − | |- align="right"
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| − | | align="left"| [[Brass]] || 580 || 8.55 || 67.8 || 6.91 || <ref name="roymech">{{cite web|url=http://www.roymech.co.uk/Useful_Tables/Matter/Copper_Alloys.html|title=Properties of Copper Alloys|work=roymech.co.uk}}</ref>
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| − | |- align="right"
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| − | | align="left"| [[Nylon]] || 78 || 1.13 || 69.0 || 7.04 || <ref>http://www.goodfellow.com/E/Polyamide-Nylon-6.html</ref>
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| − | |- align="right"
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| − | | align="left" | [[Titanium]] || 344 || 4.51 || 76 || 7.75 || <ref>{{cite web|title = ASM Material Data Sheet|url = http://asm.matweb.com/search/SpecificMaterial.asp?bassnum=MTU020|website = asm.matweb.com|accessdate = 2016-11-14}}</ref>
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| − | |- align="right"
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| − | | align="left" | [[41xx steel|CrMo Steel]] (4130) || 560–670 || 7.85 || 71–85 || 7.27–8.70 || <ref>{{Cite web|title = ASM Material Data Sheet|url = http://asm.matweb.com/search/SpecificMaterial.asp?bassnum=m4130r |website = asm.matweb.com|accessdate = 2016-08-18}}</ref><ref>{{Cite web|title = ASM Material Data Sheet|url = http://asm.matweb.com/search/SpecificMaterial.asp?bassnum=M4130A |website = asm.matweb.com|accessdate = 2016-08-18}}</ref>
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| − | |- align="right"
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| − | | align="left" | [[6061 aluminum alloy|Aluminium alloy]] (6061-T6) || 310 || 2.70 || 115 || 11.70 || <ref>{{Cite web|title = ASM Material Data Sheet|url = http://asm.matweb.com/search/SpecificMaterial.asp?bassnum=MA6061T6 |website = asm.matweb.com|accessdate = 2016-08-18}}</ref>
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| | |- align="right" | | |- align="right" |
| − | | align="left"| [[Oak]] || 90 || 0.78–0.69 || 115–130 || 12–13 || <ref>{{cite web |url=http://www.io.tudelft.nl/research/dfs/idemat/Onl_db/Id192p.htm |title=Environmental data: Oak wood |accessdate=2006-04-17 |deadurl=bot: unknown |archiveurl=https://web.archive.org/web/20071009144917/http://www.io.tudelft.nl/research/dfs/idemat/Onl_db/Id192p.htm |archivedate=9 October 2007 |df= }}</ref> | + | | align="left"| בטון || 2–5 || 2.30 || 5.22 || 0.44 || |
| | |- align="right" | | |- align="right" |
| − | | align="left"| [[Inconel]] (X-750) || 1250 || 8.28 || 151 || 15.4 || <ref>{{Cite web|title = ASM Material Data Sheet|url = http://asm.matweb.com/search/SpecificMaterial.asp?bassnum=NINC35|website = asm.matweb.com|accessdate = 2015-10-20}}</ref> | + | | align="left"| גומי || 15 || 0.92 || 16.3 || 1.66 || |
| | |- align="right" | | |- align="right" |
| − | | align="left"| [[Magnesium alloy]] || 275 || 1.74 || 158 || 16.1 || <ref>{{cite web|url=http://www.efunda.com/Materials/alloys/magnesium/properties.cfm|title=eFunda: Typical Properties of Magnesium Alloys|publisher=}}</ref> | + | | align="left"| נחושת || 220 || 8.92 || 24.7 || 2.51 || |
| | |- align="right" | | |- align="right" |
| − | | align="left" | [[Aluminium alloy]] (7075-T6) || 572 || 2.81 || 204 || 20.8 || <ref>{{Cite web|title = ASM Material Data Sheet|url = http://asm.matweb.com/search/SpecificMaterial.asp?bassnum=MA7075T6|website = asm.matweb.com|accessdate = 2015-10-20}}</ref> | + | | align="left"| [[פוליפרופילן]] / PP || 25–40 || 0.90 || 28–44 || 2.8–4.5 || |
| | + | [http://www.goodfellow.com/E/Polypropylene.html] |
| | |- align="right" | | |- align="right" |
| − | | align="left" | [[Titanium alloy]] (Beta C) || 1250 || 4.81 || 260 || 26.5 || <ref>{{cite web|title = AZo Materials Data Sheet|url = http://www.azom.com/article.aspx?ArticleID=1843|website = azom.com|accessdate = 2016-11-14}}</ref> | + | | align="left"| פוליאסטר / Polyester / PET || 80 || 1.3–1.4 || 57–62 || || |
| | + | [http://www.goodfellow.com/E/Polyethylene-terephthalate.html] |
| | |- align="right" | | |- align="right" |
| − | | align="left"| [[Bainite]] || 2500 || 7.87 || 321 || 32.4 || <ref name="Bhadeshia"> | + | | align="left"| פלדה דלת פחמן (AISI 1010) || 365 || 7.87 || 46.4 || 4.73 || |
| − | [https://web.archive.org/web/20060828062831/http://www.msm.cam.ac.uk/phase-trans/2005/chunk.html 52nd Hatfield Memorial Lecture: "Large Chunks of Very Strong Steel"] by H. K. D. H. Bhadeshia 2005. [https://archive.is/20121223005514/http://www.msm.cam.ac.uk/phase-trans/2005/chunk.html on archive.is] | + | [http://www.matweb.com/search/datasheetText.aspx?bassnum=M1010A] |
| − | </ref>
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| | |- align="right" | | |- align="right" |
| − | | align="left"| [[Balsa]] || 73 || 0.14 || 521 || 53.2 || <ref>{{cite web|url=http://www.matweb.com/search/DataSheet.aspx?MatGUID=368427cdadb34b10a66b55c264d49c23|title=MatWeb - The Online Materials Information Resource|work=matweb.com}}</ref> | + | | align="left"| פלב״מ (נירוסטה) (304) ||505 || 8.00 || 63.1 || 6.4 || |
| | + | [http://asm.matweb.com/search/SpecificMaterial.asp?bassnum=MQ304A] |
| | |- align="right" | | |- align="right" |
| − | | align="left"| [[Carbon fiber-reinforced polymer|Carbon-epoxy composite]] || 1240 || 1.58 || 785 || 80.0 || <ref> | + | | align="left"| ברונזה || 580 || 8.55 || 67.8 || 6.91 || [http://www.roymech.co.uk/Useful_Tables/Matter/Copper_Alloys.html] |
| − | McGRAW-HILL ENCYCLOPEDIA OF Science & Technology, 8th Edition, (c)1997, vol. 1 p 375</ref>
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| | |- align="right" | | |- align="right" |
| − | | align="left"| [[Spider silk]] || 1400 || 1.31 || 1069 || 109 || | + | | align="left"| [[ניילון]] || 78 || 1.13 || 69.0 || 7.04 || [http://www.goodfellow.com/E/Polyamide-Nylon-6.html] |
| | |- align="right" | | |- align="right" |
| − | | align="left"| [[Silicon carbide]] fiber || 3440 || 3.16 || 1088 || 110 || <ref>[http://www.specmaterials.com/silicarbsite.htm Specialty Materials, Inc SCS Silicon Carbide Fibers]</ref> | + | | align="left" | טיטניום || 344 || 4.51 || 76 || 7.75 || |
| | + | [http://asm.matweb.com/search/SpecificMaterial.asp?bassnum=MTU020] |
| | |- align="right" | | |- align="right" |
| − | | align="left"| [[Glass fiber]] || 3400 || 2.60 || 1307 || 133 || <ref name="vectran">{{cite web |url = http://www.vectranfiber.com/properties/tensile-properties/|title = Vectran|publisher = Vectran Fiber, Inc.}}</ref> | + | | align="left" | 41xx פלדת כרומולי (4130) || 560–670 || 7.85 || 71–85 || 7.27–8.70 || |
| | + | [http://asm.matweb.com/search/SpecificMaterial.asp?bassnum=m4130r] |
| | |- align="right" | | |- align="right" |
| − | | align="left"| [[Basalt fiber]] || 4840 || 2.70 || 1790 || 183 || <ref>{{cite web|url=http://www.rwcarbon.com|title=RWcarbon.com - The Source for BMW & Mercedes Carbon Fiber Aero Parts|work=rwcarbon.com}}</ref> | + | | align="left" | 6061 [[סגסוגות אלומיניום|סגסוגת אלומיניום]] (6061-T6) || 310 || 2.70 || 115 || 11.70 || |
| | + | [http://asm.matweb.com/search/SpecificMaterial.asp?bassnum=MA6061T6] |
| | |- align="right" | | |- align="right" |
| − | | align="left"| 1 μm [[iron]] [[Monocrystalline whisker|whiskers]] || 14000 || 7.87 || 1800 || 183 || <ref name="Bhadeshia" /> | + | | align="left"| עץ אלון || 90 || 0.78–0.69 || 115–130 || 12–13 || |
| | + | [https://web.archive.org/web/20071009144917/http://www.io.tudelft.nl/research/dfs/idemat/Onl_db/Id192p.htm] |
| | |- align="right" | | |- align="right" |
| − | | align="left"| [[Vectran]] || 2900 || 1.40 || 2071 || 211 || <ref name="vectran" /> | + | | align="left"| סגסוגת מגנזיום || 275 || 1.74 || 158 || 16.1 || |
| | + | [http://www.efunda.com/Materials/alloys/magnesium/properties.cfm] |
| | |- align="right" | | |- align="right" |
| − | | align="left"| [[Carbon fiber]] (AS4) || 4300 || 1.75 || 2457 || 250 || <ref name="vectran" /> | + | | align="left" | סגסוגת אלומיניום (7075-T6) || 572 || 2.81 || 204 || 20.8 || |
| | + | [http://asm.matweb.com/search/SpecificMaterial.asp?bassnum=MA7075T6] |
| | |- align="right" | | |- align="right" |
| − | | align="left"| [[Kevlar]] || 3620 || 1.44 || 2514 || 256 || <ref name="ngcc">{{cite web |url=http://www.ngcc.org.uk/info/ch1.html |title=Network Group for Composites in Construction: Introduction to Fibre Reinforced Polymer Composites |accessdate=2006-04-17 |deadurl=bot: unknown |archiveurl=https://web.archive.org/web/20060118112908/http://www.ngcc.org.uk/info/ch1.html |archivedate=January 18, 2006 |df= }}</ref> | + | | align="left" | סגסוגת טיטניום (Beta C)|| 1250 || 4.81 || 260 || 26.5 || |
| | + | [http://www.azom.com/article.aspx?ArticleID=1843] |
| | |- align="right" | | |- align="right" |
| − | | align="left"| [[Dyneema]] ([[Ultra-high-molecular-weight polyethylene|UHMWPE]]) || 3600 || 0.97 || 3711 || 378 || <ref>{{cite web |title= Dyneema Fact sheet | publisher = [[DSM (Company)|DSM]] |url= http://www.dsm.com/products/dyneema/en_GB/home.html |date= {{date|2008-01-01}} }}</ref> | + | | align="left"| עץ בלזה || 73 || 0.14 || 521 || 53.2 || |
| − | | + | [http://www.matweb.com/search/DataSheet.aspx] |
| | |- align="right" | | |- align="right" |
| − | | align="left"| [[Zylon]] || 5800 || 1.54 || 3766 || 384 || <ref name="Toyobo Co., Ltd.">{{Cite web|author=Toyobo Co., Ltd.|title=ザイロン®(PBO 繊維)技術資料 (2005)|url=http://www.toyobo.co.jp/seihin/kc/pbo/technical.pdf|format=free download PDF|deadurl=yes|archiveurl=https://web.archive.org/web/20120426001116/http://www.toyobo.co.jp/seihin/kc/pbo/technical.pdf|archivedate=2012-04-26|df=}}</ref> | + | | align="left"| סיבי פחמן + אפוקסי || 1240 || 1.58 || 785 || 80.0 || |
| | + | McGRAW-HILL ENCYCLOPEDIA OF Science & Technology, 8th Edition, (c)1997, vol. 1 p 375 |
| | |- align="right" | | |- align="right" |
| − | | + | | align="left"| קורי עכביש || 1400 || 1.31 || 1069 || 109 || |
| − | | align="left"| [[Carbon fiber]] (Toray T1100G) ||7000 ||1.79 ||3911 || 399 ||<ref name="Toray Composites Materials America, Co., Ltd.">{{Cite web|author=Toray Composites Materials America, Co., Ltd. | |
| − | |title=T1100S, INTERMEDIATE MODULUS CARBON FIBER|url=https://www.toraycma.com/file_viewer.php?id=5136|format=free download PDF}}</ref>
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| | |- align="right" | | |- align="right" |
| − | | align="left"| [[Carbon nanotube]] (see note below) || 62000 || 0.037–1.34 || 46268–N/A || 4716–N/A || <ref name="Strength and Breaking">{{Cite journal |first1=Min-Feng |last1=Yu |date=28 January 2000 |title=Strength and Breaking Mechanism of Multiwalled Carbon Nanotubes Under Tensile Load |doi=10.1126/science.287.5453.637 |journal=Science |volume=287 |issue=5453 |pages=637–640 |pmid=10649994 |last2=Lourie |first2=Oleg |last3=Dyer |first3=Mark J. |last4=Moloni |first4=Katerina |last5=Kelly |first5=Thomas F. |last6=Ruoff |first6=Rodney S. |bibcode=2000Sci...287..637Y |url=http://www.bimat.org/assets/pdf/00_287yu.pdf}}</ref><ref name="K.Hata">{{Cite web|author=K.Hata|title=From Highly Efficient Impurity-Free CNT Synthesis to DWNT forests, CNTsolids and Super-Capacitors |url=http://www.nanocarbon.jp/english/research/image/review.pdf |doi=10.1117/12.716279}}</ref> | + | | align="left"| סיבי סיליקון || 3440 || 3.16 || 1088 || 110 || |
| | + | [http://www.specmaterials.com/silicarbsite.htm] |
| | |- align="right" | | |- align="right" |
| − | | align="left"| Miralon [[carbon nanotube]] yarn C-series || 1375 || 0.7–0.9 || 1100 || 112 || <ref name="NanoComp">{{Cite web|author=NanoComp Technologies Inc. |title=Miralon Yarn |url=https://cdn2.hubspot.net/hubfs/339583/Offers/Miralon_Yarn.pdf}}</ref> | + | | align="left"| סיבי זכוכית || 3400 || 2.60 || 1307 || 133 || |
| | + | [http://www.vectranfiber.com/properties/tensile-properties/] |
| | |- align="right" | | |- align="right" |
| − | | align="left"| [[Colossal carbon tube]] || 6900 || .116 || 59483 || 6066 || <ref name="CCT">{{cite journal |author1=Peng, H. |author2=Chen, D. |author3=et al., Huang J.Y. | year = 2008 | title = Strong and Ductile Colossal Carbon Tubes with Walls of Rectangular Macropores | journal = Phys. Rev. Lett. | volume = 101 | issue = 14 | pages = 145501 | doi = 10.1103/PhysRevLett.101.145501 | pmid = 18851539 | bibcode=2008PhRvL.101n5501P|display-authors=etal}}</ref> | + | | align="left"| [[קבלר]] || 3620 || 1.44 || 2514 || 256 || |
| | + | [https://web.archive.org/web/20060118112908/http://www.ngcc.org.uk/info/ch1.html] |
| | |- align="right" | | |- align="right" |
| − | | align="left"| [[Graphene]] || 130500 || 2.090 <!--0.7e-6/0.335e-9 --> || 62453 || 6366 || <ref name="nobelprize.org">{{cite web |url=http://www.nobelprize.org/nobel_prizes/physics/laureates/2010/advanced-physicsprize2010.pdf |title=2010 Nobel Physics Laureates |publisher=nobelprize.org}}</ref> | + | | align="left"| [[דיינימה]] (Ultra-high-molecular-weight polyethylene: UHMWPE) |
| | + | || 3600 || 0.97 || 3711 || 378 || |
| | + | [https://www.dsm.com/products/dyneema/en_GB/home.html] |
| | |- align="right" | | |- align="right" |
| − | | align="left"| Fundamental limit || || ||{{val|9|e=13}} ||{{val|9.2|e=12}} || <ref name="Brown 2012">{{cite journal |last=Brown |first=Adam R. |arxiv=1207.3342 |title=Tensile Strength and the Mining of Black Holes |date=2012 |version= |doi=10.1103/PhysRevLett.111.211301 |volume=111 |issue=21 |journal=Physical Review Letters |bibcode=2013PhRvL.111u1301B}}</ref> | + | | align="left"| סיבי פחמן (Toray T1100G) ||7000 ||1.79 ||3911 || 399 || |
| | + | [www.toraycma.com/file_viewer.php?id=5136] |
| | |- align="right" | | |- align="right" |
| | |} | | |} |
| − | The data of this table is from best cases, and has been established for giving a rough figure.
| + | הנתונים בטבלה אינם נתונים הנדסיים, והם רק על מנת לתת אומדן גס של היכולות של חומרים שונים, כמובן. |
| − | *Note: Multiwalled carbon nanotubes have the highest tensile strength of any material yet measured, with labs producing them at a tensile strength of 63 GPa,<ref name="Strength and Breaking"/> still well below their theoretical limit of 300 GPa. The first nanotube ropes (20 mm long) whose tensile strength was published (in 2000) had a strength of 3.6 GPa, still well below their theoretical limit.<ref>
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| − | [https://archive.is/20121228021322/http://link.aip.org/link/?APPLAB/77/3161/1 "Tensile strength of single-walled carbon nanotubes directly measured from their macroscopic ropes"]
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| − | by F. Li, H. M. Cheng, S. Bai, G. Su, and M. S. Dresselhaus. {{doi|10.1063/1.1324984}}
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| − | </ref> The density is different depending on the manufacturing method, and the lowest value is 0.037 or 0.55 (solid).<ref name="K.Hata"/>
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| | | | |
| − | ==The 'Yuri' and space tethers== | + | ==קישורים חיצוניים== |
| − | The [[International Space Elevator Consortium]] has proposed the "Yuri" as a name for the SI units describing specific strength. Specific strength is of fundamental importance in the description of [[space elevator]] cable materials. One Yuri is conceived to be the SI unit for yield stress (or breaking stress) per unit of density of a material under tension. So, the units for one Yuri are ''Pa m<sup>3</sup> / kg''. This unit is equivalent to one [[Newton (unit)|N]] [[meter|m]] / [[kilogram|kg]], which is the breaking/yielding ''force'' per ''linear'' density of the cable under tension.<ref>[https://web.archive.org/web/20160114223616/http://www.isec.org/images/StrongTetherChallenge/2013/Handbook-ts2013.rev0.pdf Strong Tether Challenge 2013]</ref><ref>{{cite web|url=http://www.isec.org/sec/index.php/about-the-space-elevator/terminology#MegaYuri|title=Terminology|author=Super User|work=isec.org|deadurl=yes|archiveurl=https://web.archive.org/web/20120527065913/http://www.isec.org/sec/index.php/about-the-space-elevator/terminology#MegaYuri|archivedate=2012-05-27|df=}}</ref> A functional Earth [[space elevator]] would require a tether of 30-80 MegaYuri (corresponding to 3100–8200 km of breaking length).<ref>{{cite web|url=http://keithcu.com/wiki/index.php/Specific_Strength_in_Yuris|title=Specific Strength in Yuris|work=keithcu.com}}</ref>
| + | * [https://en.wikipedia.org/wiki/Specific_strength יחס חוזק/ משקל בויקיפדיה באנגלית] |
| − | | + | * [http://www-materials.eng.cam.ac.uk/mpsite/interactive_charts/spec-spec/NS6Chart.html Specific stiffness - Specific strength] chart, University of Cambridge, Department of Engineering |
| − | ==Fundamental limit on specific strength==
| + | ---- |
| − | The null [[energy condition]] places a fundamental limit on the specific strength of any material.<ref name="Brown 2012"/> The specific strength is bounded to be no greater than c<sup>2</sup> ~ {{val|9|e=13}}[[Kilonewton|kN]]·[[Metre|m]]/[[Kilogram|kg]], where c is the [[speed of light]].
| + | תרמו לדף זה: [[משתמש: מיכה יניב|מיכה יניב]] ואחרים... |
| − | This limit is achieved by electric and magnetic field lines, [[QCD string|QCD flux tubes]], and the fundamental strings hypothesized by [[string theory]].{{cn|date=December 2018}}
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| − | ==Tenacity (textile strength)==
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| − | {{About|the measure of fiber strength|the geologic term|Tenacity (mineralogy)|the herbicide|Mesotrione|other uses|Tenacious (disambiguation){{!}}Tenacious}}
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| − | '''Tenacity''' is the customary measure of [[Strength of materials|strength]] of a [[fiber]] or [[yarn]]. It is usually defined as the ultimate (breaking) force of the fiber (in [[gram]]-force units) divided by the [[Units of textile measurement#Denier|denier]].
| + | [[קטגוריה: הגדרות]][[קטגוריה: טיפוס סלע]][[קטגוריה: טיפוס]][[קטגוריה: טיפוס ספורטיבי]][[קטגוריה: בטיחות]][[קטגוריה: מאמרים מתורגמים ומקוריים]] |
| − | Because denier is a measure of the linear density, the tenacity works out to be not a measure of force per unit area, but rather a quasi-dimensionless measure analogous to specific strength.<ref>{{cite book |title=Principles of Polymer Systems |first=Ferdinand |last=Rodriguez |page=282 |publisher=Hemisphere Publishing |location=New York |year=1989 |edition=3rd |isbn=9780891161769 |oclc=19122722}}</ref>
| + | [[קטגוריה: טיפוס הרים]] |
| − | A tenacity of <math>1</math> corresponds to:{{cn|date=December 2018}} <math>\frac{1 {\rm \, g} \cdot 9.80665 {\rm \, m s^{-2}}}{1 {\rm \, g}/9000 {\rm \, m}}=\frac{9.80665 {\rm \, m s^{-2}}}{1/9000 {\rm \, m}}=9.80665 {\rm \, m s^{-2}} \, 9000 {\rm \, m} = 88259.85 {\rm \, m^2 s^{-2}} </math>
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| − | ==See also==
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| − | * [[Specific modulus]]
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| − | * [[Space elevator]]
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| − | * [[Space tether]]
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| − | ==References==
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| − | {{Reflist|2}}
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| − | ==External links==
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| − | * [http://www-materials.eng.cam.ac.uk/mpsite/interactive_charts/spec-spec/NS6Chart.html Specific stiffness - Specific strength] chart, University of Cambridge, Department of Engineering
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