How does one use modulus of elasticityto select wood to make a bow (as in bow and arrow) and/or the frame of a canoe? How can you measure the elasticity of a wood if it will break before you see a bending? precast In the simplest terms, the modulus of elasticity (MOE) measures a woods stiffness, and is a good overall indicator of its strength.

0000005114 00000 n This page is and will help me through my woodscience course. 0000255891 00000 n q/HnKaQRAec.&GpvGYZj/#C 7x\pFC8Y3C &hNet? startxref Use MOE with caution and keep in mind that Wood is stronger along the grain than across it. trailer 0000008582 00000 n If youre interested in getting all that makes The Wood Database unique distilled into a single, real-world resource, theres the book thats based on the websitethe Amazon.com best-seller, WOOD! Perhaps you could specify whichRead more .

xb```b``}$@(q ,AG26LE',?Q@`sv',*c! K9t*P92*7y.Nb~3\X$x*q1QOSO( 0000161721 00000 n 2589 0 obj <>stream Technical Review ITC-ME/ATCP Elastic moduli: Overview and characterization methods, Informativo Tcnico-Cientfico ITC-05/ATCP: Caracterizao dos mdulos elsticos de madeiras utilizando a Tcnica de Excitao por Impulso (TEI), Values for reference only. Vastly more resources would need to be put into wood research in order to make a moderately accurate information data base of wood rigidity among the many variables found in nature. endstream endobj 42 0 obj<> endobj 44 0 obj<>/ProcSet[/PDF/Text]/ExtGState<>>>>> endobj 45 0 obj<> endobj 46 0 obj<>stream modulus of elasticityto select wood to make a bow (as in bow and arrow) and/or the frame of a canoe? Awesome information and nice with everyone sharing comments trying to explain the modulus of elasticity. Copyright 20082022 Eric Meier. hb```b``b`e`b`b@ ! KZ+ONsv+XV*zGYH^0Vf0umA3 With a canoe working within the modulus of rupture would be fine since it will remain in the same shape. 0000014890 00000 n So with a bow modulus of elasticity is what youre looking for since thats the limit you can bend itRead more . Now, if the reference had quoted a range (the same range both times), that would be fine. 0000256799 00000 n 0

41 0 obj <> endobj 0000014045 00000 n lo,$EA&0L*`r1Xe$30}g`z#@ ! How can I buy your WOOD book. 0000011982 00000 n better Woods actually vary a lot more than that. Module of rupture is useful to know as well. 0000097164 00000 n If this ratio is 1/1000 (the material lengthens or shortens 1 mm for each meter), then the ratio gives 1000 more that stress, in the same units as yield or crush limit MOR. Identifying and Using Hundreds of Woods Worldwide, https://www.wood-database.com/rhodesian-teak/, https://www.youtube.com/watch?v=IfXW9Tw-3O0, Fluorescence: A Secret Weapon in Wood Identification, Ash Wood: Black, White, and Everything in Between, Brazilian Rosewood, East Indian, and Other Rosewoods, Genuine Lignum Vitae and Argentine Lignum Vitae. i can do the maths once I know the formulae. You can hear a little bit more of my rationale in determining values to list on the website in this longer video: https://www.youtube.com/watch?v=IfXW9Tw-3O0, 1.76 and 1.82 is not a discrepancy. This weight acts under gravity to deform this wire along its length. intial length divided by change length gives strain. 0000031815 00000 n 0000015961 00000 n

tOiGEjSs?OzjxWsv}NQgJL/t,jczZ5c|LMzUtu%wUR54l}=\e/f?/?]T&[wch_dQZlr. It also varies by altitude in the same location. As I understand it, comparing MOE and MOR is like comparing apples and oranges: theyre really completely different types of measurements. Thank you, In either case youd want to stay well within your outer limits. 0000255510 00000 n 0000005138 00000 n If you go a mile on up that same hill to 2,500 to 3,000 feet, it is 50% more dense than the sea level wood, whether green or oven dried to the sameRead more . How can it be that the MOE > MOR in some woods? Poplar, Cottonwood, and Aspen: Whats What? MOR and crushing strength are simple measurements of the wood until failure occurs. 226 0 obj <>/Filter/FlateDecode/ID[<1F288CCAB422094DBEDD7F55C28C5CE8>]/Index[194 84]/Info 193 0 R/Length 144/Prev 579788/Root 195 0 R/Size 278/Type/XRef/W[1 3 1]>>stream .m=oNfWw?8AUzULE Technically its a measurement of the ratio of stress placed upon the wood compared to the strain (deformation) that the wood exhibits along its length. 0000216750 00000 n hb```@ 9:|F'A

They show average values of the Young's modulus (modulus of elasticity) for the compression parallel to the fibers for various wood species, and average Poisson's ratio values for several high and low density wood classes. ), You can help support the site by buying one of these resources, designed and published by The Wood Database.

How can there be less force required to break something rather than bend it? 0000007179 00000 n Are Rosewoods (and Bubinga) really banned by CITES? 0000161653 00000 n H\n0F 3 ! 0 endstream endobj 47 0 obj<> endobj 48 0 obj<>stream The thing that folks miss here is that in using Youngs modulus with say metals the general assumption is that it is the same in tensile stress as in compressive stress. endstream endobj startxref xref 0000004331 00000 n Its not only the force (stress) put on the wood, but also the amount that the wood has bentRead more , (This is a monthly update, and your email will be kept private.

If so, I would agree with that. Hey, I have a question about MOR and MOE. There are at least 2 reasons there are different published values for E for the same named wood and neither has to do with compression or tension of the wood fibers.

277 0 obj <>stream What I find interesting is how the MOR can be lower than the MOE. 0000010687 00000 n I am attempting to calculate whether a particular timber section (say C16 grade) will be strong enough, i.e. The force is pure Tensile Force. ASSOCIAO BRASILEIRA DE NORMAS TCNICAS. But it is most definitely a discrepancy in the database. S)%Nm\sDvF!],ta1af=nH(MQg3IHgBk}'tfe^a)1;2n 8kSp1;7Cdai0 h@.gq,BCCQ,qK#LZ@J m` 3m~0I0D01}&@"r&eJQL?0`|.PozT,^k 0000255442 00000 n will not snap, under the wind load, and also the deflection at its tip.

Donating wood samples and pictures of wood itemsIf youve got a new or unusual wood species that isnt on the site, please consider sharing it with the rest of us! 0000097261 00000 n Scots pines at sea level to 500 feet are soft and weak. MOE is the ration between the stress and the (non-dimensional) relative elongation. Support me directly through PatreonIf youve been helped by the Wood Database, consider saying thanks and helping to support the project. So in a wooden beam under load the modulus on the tension side of the beam is not the same as in the compression side. Modulus elasticity is the ratio of stress to strain of a material in deflection (say in a beam) and is sometimes called Youngs modulus. For wood, I dont know if they are the same or different. 0000002937 00000 n 41 58 The properties are expressed in average values that may vary significantly depending on the processing and quality of the material. 0000281631 00000 n Those are good values to use. <<4a36096b115b53459eeba6400d546f47>]>> And GigaPascals (GPa) are often used. The tables below show the values of Young's modulus (modulus of elasticity) and Poisson's ratio at room temperature for woods and composite materials used in engineering. 0000004221 00000 n i can work out the wind force and the bending moment at the posts base, just not how to determine its strength etc. For exact values, characterize the material using Sonelastic. 0000005919 00000 n 0000007036 00000 n This constant as stated reflects the stiffness (resistance to deflection) of a material under a load but only in its elastic range, the relatively small range in which it springs back without any deformation after the load is removed. Carroll It doesnt look like anything unfortunately. 0000014317 00000 n It can be clearly seen in the above woods database diagram, that a system of compression and tension is happening. I think youd find that wood does bend easily given the same dimensions of steel.

%PDF-1.6 % That is, we understand that crushing strength in psi is the force in pounds to crush a one square inch block of wood, and the tensile strength would be how many pounds a one square inch section could hold if we cold hang that weight from it.

0000005943 00000 n Youngs mod is then calculated based on the force (weight times acceleration due to gravity) and area of the wire. In practical terms, the number itself isnt all that meaningful, but it becomes useful to use in comparison with other woods. The Modulus of Elasticity published in many texts in the past was based on bending tests instead of opposing shear forces used in modern testing procedures. 0000010223 00000 n 0000134827 00000 n 107 p. BODIG, J., JAYNE, B. Malabar (EUA), Krieger Publishing Company, 1993. Im curious what sources you use for the modulus of elasticity? "}lF/2paPjjZ9ouReSS%sDCR[y0-"6#-oo^WO+KO+YzVE]8*?|ew H\j >w%K} Thswe3i,;0h.$B6vqSk% Try finding some rebar and a wooden dowel of the same diameter and length and compare the two. Mechanics of wood and wood composites. So in this exampleRead more , 1. As we all know, Wood is anisotropic, therefore strength is highly dependent on relative direction of the grain. endstream endobj 49 0 obj<> endobj 50 0 obj<> endobj 51 0 obj<>stream 0000015483 00000 n

0000011716 00000 n 0000000016 00000 n

endstream endobj 195 0 obj <>>> endobj 196 0 obj <> endobj 197 0 obj <>/ExtGState<>/Font<>/ProcSet[/PDF/Text]/XObject<>>>/Rotate 0/TrimBox[0.0 0.0 595.276 841.89]/Type/Page>> endobj 198 0 obj <>stream The bending test didnt consider or compute either tension or compression in determining the value for E. The formula used the applied force, the span, the moment of inertia, and the deflection in a formula that is available in many older textsRead more , This article says red oak has a MOE of 1,820,000 lbf/in2 (12.50 GPa), but looking at the database page for red oak I find, Elastic Modulus: 1,761,000 lbf/in2 (12.14 GPa), The short answer is that I use the average of as many credible sources of data that I can find, and when this article was written, I was quoting from only one source, while the page on red oak has since been updated to reflect the most recent (averaged) data. 0000013595 00000 n H 6X$A:o%1 LhN*``ZpaAG"A[t7`.{T~-348; L@z HG2px ar*j` 6~b It is only after you combine this value E with geometric dimensional properties of the element being loaded or designed that you can compute a relationship between load and deflection (movement). H\n@~9&?`B"@$D{`--5oS.Hk jMvwI?dN]n]ifz4n>TI)9I?BC8O&3i) 194 0 obj <> endobj All Rights Reserved. Bow Woods (from a mathematical perspective), Four Common Finishing Mistakes (and how to avoid them). 0000065201 00000 n For example: The Modulus elacticity of Steel is 200GPa, and some softwood timbers are around 7GPa. %%EOF Wood varies in the same species by geographical location. With common engineering materials this figure is so important that huge amounts of testing have been done to determine the MOE/Youngs modulusRead more . %%EOF 0000215688 00000 n For instance,Hickory is known to have excellent strength properties among domestic species in the US, and has a MOE of 2,160,000 lbf/in2 (14.90 GPa). 0000002662 00000 n 0000007750 00000 n

Thank you, Donating wood samples and pictures of wood items, WOOD! endstream endobj 2560 0 obj <>/Metadata 226 0 R/Outlines 403 0 R/PageLayout/OneColumn/Pages 2545 0 R/StructTreeRoot 468 0 R/Type/Catalog>> endobj 2561 0 obj <>/Font<>/ProcSet[/PDF/Text/ImageB]/Properties<>/XObject<>>>/Rotate 0/StructParents 97/TrimBox[0.0 0.0 595.276 841.89]/Type/Page>> endobj 2562 0 obj <>stream 2. This white paper presents the theory and proposal of a methodology for the non-destructive elastic moduli characterization of woods and wood products using the Impulse Excitation Technique. 0000216373 00000 n 0000255612 00000 n This number is given for wood that has been dried to a 12% moisture content, unless otherwise noted.

I presume this means better for structural engineering? 0000216658 00000 n The true lengthwise deformation would be given by Pythagoras. (A fair comparison might be to compare MOR with Crushing Strength.) 0000012448 00000 n Higher value means more stiffness which is not necessarily better for instrument making, probably archery and whatnot if the wood needs to bend a lot. hbbd```b``9"gH``6\ f`v;]f' Re'6FD QpK?@"@D~0 }I what exactly would that look like in a test? The MOR occurs at a much much lower force than the MOE. It contains many of the most popular articles found on this website, as well as hundreds of wood profileslaid out with the same clarity and convenience of the websitepackaged in a shop-friendly hardcover book.

There is of course no obligation, but if youd like to give back and ensure that the project continues to grow, consider supporting me on Patreon. 2559 0 obj <> endobj A.

0000008952 00000 n 5/5 Pine cones. MOE is a completely different animal in that it is a RATIO of two different measurements.

Hang a weight from steel wire; say 1 pound. hXmo7+- 0000257231 00000 n With wood this is definitely not the case. This is saying the column gets shorter by an amount delta equal to the product of the load (P) and the length (L) of the column divided by the product of the modulus (E) and the area (A). I will assume that I am misunderstanding something here. Hence difficult to analyse. h_o8760pe]u:Jbcle[%;uo7,H\PUI}+K$EicaK[LHyLMZn.xDd)qB62_(ZY^/-|>f8 eYA{N{F)8&p#Ia-ba`ss[A%TPB4+nRf$a]sS[,r*+2ndQZGq7oN). Look at the https://www.wood-database.com/rhodesian-teak/ for instance. Perhaps you do? With wood this springy range is much wider than other materials say a sheet of glass, but almost anything can have its MOE determined. OCa~Qbh9fP56P m*.5 d-D-Z@r. Identifying and Using Hundreds of Woods Worldwide. 0000007895 00000 n 0000134895 00000 n '.MqG8Y2$W{ffWl%`KgIiemV2g=Zg\hXSj"VNRkHI6Z[P|"I$34xGCJB/ F,V~Ep*%W7Q%h$Q?\_oQ/GL_Mt?zn@@Qq61M.ic-"$4lF>:VF8yW2F2j>}t?7]Sk?j&w,xtWz,^7Sxu3/p68|n^owwJM+z0:o>vXq:{oU5"\73''W!dRV#(H]g_ G a/[_O~%X>_LF.X?6iR,MZhxu5tR#I2'v>$vE1. Projeto de estruturas de madeira, NBR 7190.

MOE is expressed in pounds-force per square inch (lbf/in2) or gigapascals (GPa).

For example, a quater-sawn guitar neck is much stiffer then one made from plain-sawn wood. 0000011192 00000 n See my page on donating wood samples for more info. Basically, how much force did it require to break the wood of a given size (usually standardized sizes are used). %PDF-1.5 % For example, a simple expression of the shortening of a column under load would be delta = P*L / (E*A).

0000003277 00000 n I have searched Amazon for book entitled WOOD and no luck? Rio de Janeiro, 1997.

It makes it possible to read different explanations. Even 1.80 and 1.81 would be a discrepancy. 0000003549 00000 n Seems to be a lot of questions about modulus of elasticity aka Young s modulus. 8ts2K22Laac\8#_e@(W t!q Actually, it is a discrepancy. f^A^a^A^a^A^y#fVO>-|Zi7o,YzJ}R_W+Ju5yyyyyyyyyy=8xpC]\:]g\sE\|}'88q4#: &h. 9"B 0000096875 00000 n I understand it much better now, thanks for taking the time to explain it :). Can anyone help me with the formulae? 2580 0 obj <>/Filter/FlateDecode/ID[<1D833D53DD7A6D4994C7824BB773F2EC>]/Index[2559 31]/Info 2558 0 R/Length 102/Prev 1136264/Root 2560 0 R/Size 2590/Type/XRef/W[1 3 1]>>stream This page has a link to buy the book: https://www.wood-database.com/book/. https://en.wikipedia.org/wiki/Flexural_modulus I think the flexural modulus also depends on the orientation of the grain, radial or tangential, to the force. 0000096145 00000 n 0000004109 00000 n

Im also interested in getting photos of completed wood projectsespecially of obscure or lesser known woods. From your diagram, it appears you are actually talking about the flexural modulus, which may or may not be equivalent to the tensile modulus or the compressive modulus, depending on the material. In comparison,Red Oak is another well-known wood used in cabinetry and furniture, and has a MOE of 1,820,000 lbf/in2 (12.50 GPa). Module of rupture doesnt account for fatigue though. Units: The units are Pascals after the late French physicist Blaise Pascal. If the E value is to have any meaning, it would also mean that if weRead more , There is huge confusion in calculating MOE in Plywood please help us is there is any other method to calculate the said parameter Unit= N/mm2. endstream endobj startxref %PDF-1.6 % A reference should not give different values for the same thing.

%%EOF 0000001456 00000 n 0000002116 00000 n

0000006874 00000 n

I am curious to better understand exactly how the values and units translate into real world measurable terms. 4*9ZR2]V9)z-zBZ.|M\NneL64-hYEX 3w%+lFs,E 0000006898 00000 n The elastic moduli (Young's Modulus, Shear modulus and Poisson's ratio) and damping of composites can be accurately characterized by the non-destructive Sonelastic Systems testing at room temperature and as a function of temperature and/or time.

It is not like you are testing a mill run of SAE 1035 steel, or something. Bend a board to much and it may not break but it wont necessarily spring back to its original shape. NY|Q14_H~2YFB$nO$$E"5)Lj{ru/ jOr~ n

1.

But giving two different numbers for the same thing is a discrepancy.

M:o{{7_7L3:uIkex}O,%o;."9"/ld/KpI.#5R0B}P_/#;0k j k\ hbbd```b``A$=d"9@$n0i"Y5h0&IN0i~ &/7`C`5 + The knowledge of exact values is vital for the optimization of the material's use and for the reliability of simulations via finite elements. The higher the values of Youngs modulus the better.

I go with generalities and overdesign. The specific links on this site are affiliate links (as an Amazon Associate I earn from qualifying purchases) and help support the site at no extra cost to you.

This MOE is giving us forces in millions of lbs per square inch. 0000002178 00000 n LR= 43 0 obj<>stream 0

The exact values can be measured with the Sonelastic Systems of non-destructive testing, both, at room temperature or as a function of temperature and/or time. 0000009703 00000 n Thats the point at which youd get fracturing in the grain. 0000013069 00000 n Perhaps you meant to say it is not a large difference. Elastic moduli and damping characterization are also employed in the engineering of new variations of these materials, such as panels and wooden boards. D=y0&qs^CdRy'?_ Qp|T V6w[lQY,`,` `&sGHt0u0v4Xtu0t0wt4Ftt0)u CZP@P(g ,Pb a4c1H6ia 'p~fB?T3J0 J\hPo(nmZMwE x9>``cyAv$t}AH320~gJ(CP~`[T 0]>Q8 This section of the website is a summary of an extract from the Technical Review ITC-ME/ATCP Elastic moduli: Overview and characterization methods, and Informativo Tcnico-Cientfico ITC-05/ATCP: Caracterizao dos mdulos elsticos de madeiras utilizando a Tcnica de Excitao por Impulso (TEI) - (*ptBr language).
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