Which came first, the Green Ash or the White Ash species
What prompted this question? Well recently I bought some lumber of white
ash, plus hickory plus white oak and various others. I do not believe the data on strength of wood is accurate and am wanting to test these woods myself. I believe oak is stronger than hickory. I believe the strength of hickory is a sales hype. The reason I say this is because in history trebuchets were built out of oak and not hickory even though England had hickory species and ash species. And because the growth pattern of oaks allows horizontal branches which means the wood has to be tougher and stronger to grow horizontal. I also want to test spruce for strength because a spruce bears the full force of wind so its wood must be strong. But the question that rose in my mind is whether GreenAsh came first in geologic history or whether WhiteAsh and which mutated and gave rise to the other? I accept Darwin Evolution theory only as a algorithm or rule and not as a theory. Let me call it the Darwin-Evolution-Rule. So according to that Rule, which of the ashes existed first? Was it GreenAsh that mutated to create the WhiteAsh species or vice versa? If I had to guess I would say the WhiteAsh came first and gave rise to the GreenAsh and I would guess that because the GreenAsh has a wider range of habitat. Because in the Rule of its survival of the fittest it is less likely for a species to give rise to a weaker species that thence increases its range of habitat. Based on *likelihood*. Question: what is in the genetics of GreenAsh that it can live where-ever WhiteAsh lives and then some more? Is it that GreenAsh is less picky as to pH soil conditions? Is it that GreenAsh can take wind better than WhiteAsh? Is it that GreenAsh can survive with less water? So I wonder if a Genome project can be run on GreenAsh and WhiteAsh and whether the genome can date whether GreenAsh was a mutation of WhiteAsh and has now become the dominant ash species? I am thinking that DNA is a fossil record itself and can tell us which species of two contending species came first. And this DNA dating is very important for the human species itself in that it can tell us that Stonethrowing came before bipedalism and created bipedalism. Archimedes Plutonium www.iw.net/~a_plutonium whole entire Universe is just one big atom where dots of the electron-dot-cloud are galaxies |
Archimedes Plutonium schreef
The reason I say this is because in history trebuchets were built out of oak and not hickory even though England had hickory species and ash species. *** England has no hickory species (perhaps you are confusing England with China), but yes hickory is stronger than oak. A matter of record. PvR |
In article , Archimedes Plutonium
writes England had hickory species There were no hickories (Carya) in England during historical times until they were introduced from America. There are no Carya species native to Europe (1 native to China, 1 to Tonkin, the remainder to North America) so it's likely that hickories have been absent from England for a long time. Googling finds sites that report that Carya has been extinct in Europe for 2 million years. -- Stewart Robert Hinsley |
Chickens and eqgs ought to be asked that question. They have more experience
:=) Bill |
On Sat, 09 Oct 2004 12:01:12 -0500, Archimedes Plutonium
wrote: What prompted this question? Well recently I bought some lumber of white ash, plus hickory plus white oak and various others. I do not believe the data on strength of wood is accurate and am wanting to test these woods myself. I believe oak is stronger than hickory. I believe the strength of hickory is a sales hype. I can tell you that most types of hickory are harder to split than most types of oak. This bears mostly on the degree of crosslinking (cross grain fibers) in the wood. England had hickory species and ash species. And because the growth pattern of oaks allows horizontal branches which means the wood has to be tougher and stronger to grow horizontal. This is a nice theory, but I don't think it holds up well in reality. American Elm, which bears limbs mostly erectly, is one of the toughest woods around. I would defy anyone to hand split an 18" x 18" diameter log down the middle. Steve Turner |
Stewart Robert Hinsley wrote: In article , Archimedes Plutonium writes England had hickory species There were no hickories (Carya) in England during historical times until they were introduced from America. There are no Carya species native to Europe (1 native to China, 1 to Tonkin, the remainder to North America) so it's likely that hickories have been absent from England for a long time. Googling finds sites that report that Carya has been extinct in Europe for 2 million years. -- Stewart Robert Hinsley I had a mind glitch when I wrote that. I was thinking at that moment that Butternut was a Carya species and that England has butternuts. But I was totally mistaken. Anyway getting back to the issue of test of strength of woods, the white ash I have is heavier and denser than the hickory and both are reported to be stronger than oak. So England had no hickories for trebuchets but they surely had ash trees. Whether they had both White and Green Ash, I do not know. But if Ash is nearly equivalent to hickory in terms of strength, then why did they build the trebuchets out of oak when ash was available? My guess is that oak is superior to various tests of strength and that strength relies on various dimensions and tests. For example, the test of placing boards of white oak, white ash and hickory of equal length width and depth and adding weights to the end of the board until the board snaps. I would guess oak outlasts the hickory and whiteash. Then there is the projectile test of which is least impervious to a projectile. Then there is the durability test for it seems as though oak lasts longer as a flooring then does hickory which seems to peel off in long splinters. Archimedes Plutonium www.iw.net/~a_plutonium whole entire Universe is just one big atom where dots of the electron-dot-cloud are galaxies |
P van Rijckevorsel wrote: Archimedes Plutonium schreef The reason I say this is because in history trebuchets were built out of oak and not hickory even though England had hickory species and ash species. *** England has no hickory species (perhaps you are confusing England with China), but yes hickory is stronger than oak. A matter of record. PvR I was confusing Butternut as being a Carya species. But never mind my mistake. It is more important to be able to use the Genome Project on the two ash species since they are so similar. To use that A,C,T,G coding as if it was a fossil record itself. To decipher from the A,C,T,G which came first, the Green Ash or the White Ash and which mutated giving rise to the other species. The Genome Project is relatively new and has a huge potential of being a fossil recorder of the ancient geological past history. Those A,C,T,G codings should be able to date one species from another species and tell us which was the parent-species. This should be of great importance to the science of anthropology in that we can unravel the A,C,T,G that is bipedalism and why chimps do not have bipedalism and thus work backwards showing that chimps throw underarm but not overarm and because throwing precedes bipedalism. So as the chimps continue to get better at throwing they eventually (given about 2 to 3 million years and if humans were not around to extinct them) will become bipedal from their throwing behaviour. I pick on the Ash species to make a Genome-Fossil check because I am guessing that the genome of WhiteAsh to GreenAsh is almost identical. Moreso than the genome difference between chimpanzee and human. Sometime in the future there will be a stunning news report that uses the Genome of one species to indicate the evolutionary history of a similar species. That uses the Genome as a Fossil record. And I think Ash would be a nice candidate. Archimedes Plutonium www.iw.net/~a_plutonium whole entire Universe is just one big atom where dots of the electron-dot-cloud are galaxies |
Archimedes Plutonium schreef
I was confusing Butternut as being a Carya species. * * * Yes, oak is stronger than butternut. No, England does not have butternuts. PvR |
In article , Archimedes Plutonium
writes Anyway getting back to the issue of test of strength of woods, the white ash I have is heavier and denser than the hickory and both are reported to be stronger than oak. So England had no hickories for trebuchets but they surely had ash trees. Whether they had both White and Green Ash, I do not know. But if Ash is nearly equivalent to hickory in terms of strength, then why did they build the trebuchets out of oak when ash was available? England has neither white nor green ash; both are American species. Rather than speculating you could find a web site which lists the trees native to Britain (there's appreciably less than 100). You might also note that there's very few (perhaps ever zero) species of tree native to both Britain and North America. -- Stewart Robert Hinsley |
. I do not believe
the data on strength of wood is accurate and am wanting to test these woods myself. I believe oak is stronger than hickory. The mechanical properties of native hardwood species of wood are well known, true hickories are "stronger" than white oaks. Do include black locust in your trials, now that would give the hickory some competition. |
Archimedes Plutonium wrote in message ...
What prompted this question? Well recently I bought some lumber of white ash, plus hickory plus white oak and various others. I do not believe the data on strength of wood is accurate and am wanting to test these woods myself. I believe oak is stronger than hickory. I believe the strength of hickory is a sales hype. The reason I say this is because in history trebuchets were built out of oak and not hickory even though England had hickory species and ash species. And because the growth pattern of oaks allows horizontal branches which means the wood has to be tougher and stronger to grow horizontal. I also want to test spruce for strength because a spruce bears the full force of wind so its wood must be strong. But the question that rose in my mind is whether GreenAsh came first in geologic history or whether WhiteAsh and which mutated and gave rise to the other? I accept Darwin Evolution theory only as a algorithm or rule and not as a theory. Let me call it the Darwin-Evolution-Rule. So according to that Rule, which of the ashes existed first? Was it GreenAsh that mutated to create the WhiteAsh species or vice versa? That's a good thing, since that's what Darwin eventually accepted it as. After he rediscovered that Galopagos Turtle and Albatros eggs, are not only not warm-blooded, or mammals, they are like many trees, and philosphers of evolution: Tepid, Flaky, and lost in the woods, unscientific, memoryless, and stupid. Since neither trees not grasses have cells, like the evolutionary bacteria that eats then do. They have very abrasive cellulose. And the reason that the data on both ash and hickory is incomplete, and will remain forver incomplete is for the reason that trees have no strength. They have a rigidity index, that allows them to survive on the slopes of volcanoes. Which is why they are the only things on Earth that are as old as rock jokes and volcanoes. Since trees are just like grasses, they don't evolve. They go whereever the wind pushes and pulls them. Be it solar wind, or atmospheric wind. And they are no more evolutionary advanced than the granite and sandstone rocks that they roost on. If I had to guess I would say the WhiteAsh came first and gave rise to the GreenAsh and I would guess that because the GreenAsh has a wider range of habitat. Because in the Rule of its survival of the fittest it is less likely for a species to give rise to a weaker species that thence increases its range of habitat. Based on *likelihood*. But ash are not really trees. They are strains, or hybrids of trees. Since they are some of the few species of trees, that their bark is infinately more valuable than their leaves. |
IntarsiaCo wrote: . I do not believe the data on strength of wood is accurate and am wanting to test these woods myself. I believe oak is stronger than hickory. The mechanical properties of native hardwood species of wood are well known, true hickories are "stronger" than white oaks. Do include black locust in your trials, now that would give the hickory some competition. The thing I remember most about locust is when I apply a chainsaw it feels as if I am bouncing on a rock and not wood. But anyway, I am set to apply various tests on whiteAsh, whiteOak, Hickory, locust, elm, mulberry, blackwalnut, cedar, redwood, spruce and other woods. I suspect the old tests are not scientific enough and pandering to a sales industry where hickory is promoted. I believe the test for strength is multidimensional and that hickory surpasses one test of shock absorbing and on the basis of just that one superiorty bracket it is called the strongest when in fact it is not the strongest in various other tests. One test already shows that my hickory is inferior in strength to whiteAsh and whiteOak in the tendency of hickory to peal off in huge long splinters so that if a flooring were made of hickory would not outlast oak. And obviously hickory grows branches that are seldom horizontal whereas Oak, and they call it "spooky oak not for nothing" can grow branches horizontal to the ground indicates enormous strength in wood. And Ash seems better able to grow horizontal than hickory, so in another test of strength oak should excel both whiteAsh and Hickory in that category. Obviously spruce is dense in form and its wood must reflect its ability to withstand huge winds as the saying goes "you cannot throw a cat throw a spruce tree". So it gives good reason as to why airplane builders prized spruce wood. So that perhaps given the weight per strength category spruce may outbest even the hardwoods. I am going to test locust after I get a equal test piece, but I already know one superior strength test of locust in that it dulls my chainsaw or any saw faster than any wood I know of. Soon I should have some numbers data on strength such as a weight-flex test, a penetration test, a density test, etc. Archimedes Plutonium www.iw.net/~a_plutonium whole entire Universe is just one big atom where dots of the electron-dot-cloud are galaxies |
Wed, 13 Oct 2004 02:44:55 -0500 Archimedes Plutonium wrote:
IntarsiaCo wrote: . I do not believe the data on strength of wood is accurate and am wanting to test these woods myself. I believe oak is stronger than hickory. The mechanical properties of native hardwood species of wood are well known, true hickories are "stronger" than white oaks. Do include black locust in your trials, now that would give the hickory some competition. The thing I remember most about locust is when I apply a chainsaw it feels as if I am bouncing on a rock and not wood. But anyway, I am set to apply various tests on whiteAsh, whiteOak, Hickory, locust, elm, mulberry, blackwalnut, cedar, redwood, spruce and other woods. I suspect the old tests are not scientific enough and pandering to a sales industry where hickory is promoted. I believe the test for strength is multidimensional and that hickory surpasses one test of shock absorbing and on the basis of just that one superiorty bracket it is called the strongest when in fact it is not the strongest in various other tests. One test already shows that my hickory is inferior in strength to whiteAsh and whiteOak in the tendency of hickory to peal off in huge long splinters so that if a flooring were made of hickory would not outlast oak. And obviously hickory grows branches that are seldom horizontal whereas Oak, and they call it "spooky oak not for nothing" can grow branches horizontal to the ground indicates enormous strength in wood. And Ash seems better able to grow horizontal than hickory, so in another test of strength oak should excel both whiteAsh and Hickory in that category. Obviously spruce is dense in form and its wood must reflect its ability to withstand huge winds as the saying goes "you cannot throw a cat throw a spruce tree". So it gives good reason as to why airplane builders prized spruce wood. So that perhaps given the weight per strength category spruce may outbest even the hardwoods. I am going to test locust after I get a equal test piece, but I already know one superior strength test of locust in that it dulls my chainsaw or any saw faster than any wood I know of. Soon I should have some numbers data on strength such as a weight-flex test, a penetration test, a density test, etc. Today I have some numbers: I took 3 boards of 4,000 mm long by 170 mm wide by 25 mm thick of WhiteOak, Hickory and WhiteAsh and put them through various tests of strength. A weight test where a weight is placed in the middle of the board and WhiteAsh flexed off center by 145 mm and Hickory flexed 106 mm and Oak flexed 70 mm. So Oak is clearly the strongest and not Hickory! I am guessing the literature puts hickory as stronger than oak and the only reason I can think of this bias and untruth is perhaps for sales of hickory wood by the huge lumber industry of hickory versus whiteoak. I ran a density test because flex strength is dependent on density and WhiteOak won again for the Hickory was 97% as dense as WhiteOak and the WhiteAsh was 95% as dense as WhiteOak. Finally I ran a penetration test for strength by shooting BBs into the wood and WhiteOak won this test also but surprizingly WhiteAsh won over Hickory, however it appeared that WhiteAsh splinters more often than does hickory in penetration tests and does not leave a nice smooth depression. My tests confirm the obvious facts of Nature itself. Anyone can observe that only WhiteOak is able to grow with branches horizontal to ground and so the wood must be stronger in order to hold up that weight whereas Hickory and WhiteAsh tend to grow branches more vertical because of a wood that is less strong as WhiteOak. This *Nature's Obvious Test* is reconfirmed in the evergreen softwoods in that Colorado BlueSpruce is the strongest per weight and that this tree is very dense exposed to *wind force* and so the wood has to be extra strong to bear the wind forces. I have not located a bluespruce board to test and perhaps most people just do not want to lose their beautiful Colorado BlueSpruce and in fact I can more easily find Redwood than ColoradoBlueSpruce. So what my missive above hopefully generates is for some "real scientists" and not some lumber sales people go back and really do a great job as to the strength of woods. Because, hey, Nature itself implies that BlueSpruce and WhiteOak **are likely to be** superior. Archimedes Plutonium www.iw.net/~a_plutonium whole entire Universe is just one big atom where dots of the electron-dot-cloud are galaxies |
Archimedes Plutonium wrote:
Wed, 13 Oct 2004 02:44:55 -0500 Archimedes Plutonium wrote: IntarsiaCo wrote: . I do not believe the data on strength of wood is accurate and am wanting to test these woods myself. I believe oak is stronger than hickory. The mechanical properties of native hardwood species of wood are well known, true hickories are "stronger" than white oaks. Do include black locust in your trials, now that would give the hickory some competition. The thing I remember most about locust is when I apply a chainsaw it feels as if I am bouncing on a rock and not wood. But anyway, I am set to apply various tests on whiteAsh, whiteOak, Hickory, locust, elm, mulberry, blackwalnut, cedar, redwood, spruce and other woods. I suspect the old tests are not scientific enough and pandering to a sales industry where hickory is promoted. I believe the test for strength is multidimensional and that hickory surpasses one test of shock absorbing and on the basis of just that one superiorty bracket it is called the strongest when in fact it is not the strongest in various other tests. One test already shows that my hickory is inferior in strength to whiteAsh and whiteOak in the tendency of hickory to peal off in huge long splinters so that if a flooring were made of hickory would not outlast oak. And obviously hickory grows branches that are seldom horizontal whereas Oak, and they call it "spooky oak not for nothing" can grow branches horizontal to the ground indicates enormous strength in wood. And Ash seems better able to grow horizontal than hickory, so in another test of strength oak should excel both whiteAsh and Hickory in that category. Obviously spruce is dense in form and its wood must reflect its ability to withstand huge winds as the saying goes "you cannot throw a cat throw a spruce tree". So it gives good reason as to why airplane builders prized spruce wood. So that perhaps given the weight per strength category spruce may outbest even the hardwoods. I am going to test locust after I get a equal test piece, but I already know one superior strength test of locust in that it dulls my chainsaw or any saw faster than any wood I know of. Soon I should have some numbers data on strength such as a weight-flex test, a penetration test, a density test, etc. Today I have some numbers: I took 3 boards of 4,000 mm long by 170 mm wide by 25 mm thick of WhiteOak, Hickory and WhiteAsh and put them through various tests of strength. A weight test where a weight is placed in the middle of the board and WhiteAsh flexed off center by 145 mm and Hickory flexed 106 mm and Oak flexed 70 mm. So Oak is clearly the strongest and not Hickory! STIFFEST.... is not Strongest. The deflection under load measures stiffness. The load required to cause fracture is a measure of strength. STRENGTH isn't Stiffness. It is technology. Misuse of the basic terms helps make people believe you are dumb and ignorant. Use the terms correctly, then they will have to listen a little more carefully to make the negative conclusion. |
"Archimedes Plutonium" wrote in message
... A weight test where a weight is placed in the middle of the board and WhiteAsh flexed off center by 145 mm and Hickory flexed 106 mm and Oak flexed 70 mm. So Oak is clearly the strongest and not Hickory! No, you've proved that Oak is the stiffest, not that it is the strongest. You need to break the samples to find out which is strongest. A 4-point bending test would be best. -- Terry Harper http://www.terry.harper.btinternet.co.uk/ |
Thu, 14 Oct 2004 20:53:26 +0000 (UTC) Terry Harper wrote:
"Archimedes Plutonium" wrote in message ... A weight test where a weight is placed in the middle of the board and WhiteAsh flexed off center by 145 mm and Hickory flexed 106 mm and Oak flexed 70 mm. So Oak is clearly the strongest and not Hickory! No, you've proved that Oak is the stiffest, not that it is the strongest. You need to break the samples to find out which is strongest. A 4-point bending test would be best. -- Terry Harper Is there a scientific definition of "strength" and "stiffness" where the two concepts are clearly distinguished or are they a mix of one another? For instance a bicycle tubing of aluminum versus steel where both hold up weight but where the aluminum tubing is made oversized for stiffness. So now if we add weight to these two bicycles and when they break do we call that strength. Another example is wire of steel or copper where they have stiffness contrasts and they hold different weights before they break. So is the concept of strength tantamount to the concept of " the point at which it breaks under force"? So is the science concept of strength one and the same as the point at which the item breaks. I am not sure I want to break those boards. Is there another test for strength other than breaking the boards? I am not sure that strength as a concept is in isolation of other concepts. So I wonder how many concepts relating to Strength there exists for wood? In that stiffness is a dependent concept and Penetration is a dependent concept of strength. Come to think about it, if Breaking is tantamount to Strength then the science concept of strength really is integral to the chemical bonds involved. So that Chemical Bonds is responsible to strength and that to find out which is stronger WhiteOak or Hickory we must analyze their chemical bonds atom by atom. And maybe I should be looking into the chemical bonds of oak wood compared to hickory. Whether there are more powerful bonds in oak versus hickory. Perhaps oak is stronger than hickory because it has more covalent bonds and less hydrogen bonds than does hickory. Has anyone done a chemistry analysis of oak wood versus hickory as per chemical bonds. Stronger bonds would be those with fewer impurities. As anything in science, the more you dig deeper, the more a ocean of new things opens up. Archimedes Plutonium www.iw.net/~a_plutonium whole entire Universe is just one big atom where dots of the electron-dot-cloud are galaxies |
On Thu, 14 Oct 2004 22:36:41 -0500, Archimedes Plutonium
wrote: Thu, 14 Oct 2004 20:53:26 +0000 (UTC) Terry Harper wrote: "Archimedes Plutonium" wrote in message ... A weight test where a weight is placed in the middle of the board and WhiteAsh flexed off center by 145 mm and Hickory flexed 106 mm and Oak flexed 70 mm. So Oak is clearly the strongest and not Hickory! No, you've proved that Oak is the stiffest, not that it is the strongest. You need to break the samples to find out which is strongest. A 4-point bending test would be best. -- Terry Harper Is there a scientific definition of "strength" and "stiffness" where the two concepts are clearly distinguished or are they a mix of one another? For instance a bicycle tubing of aluminum versus steel where both hold up weight but where the aluminum tubing is made oversized for stiffness. So now if we add weight to these two bicycles and when they break do we call that strength. Another example is wire of steel or copper where they have stiffness contrasts and they hold different weights before they break. So is the concept of strength tantamount to the concept of " the point at which it breaks under force"? So is the science concept of strength one and the same as the point at which the item breaks. I am not sure I want to break those boards. Is there another test for strength other than breaking the boards? I am not sure that strength as a concept is in isolation of other concepts. So I wonder how many concepts relating to Strength there exists for wood? In that stiffness is a dependent concept and Penetration is a dependent concept of strength. Come to think about it, if Breaking is tantamount to Strength then the science concept of strength really is integral to the chemical bonds involved. So that Chemical Bonds is responsible to strength and that to find out which is stronger WhiteOak or Hickory we must analyze their chemical bonds atom by atom. And maybe I should be looking into the chemical bonds of oak wood compared to hickory. Whether there are more powerful bonds in oak versus hickory. Perhaps oak is stronger than hickory because it has more covalent bonds and less hydrogen bonds than does hickory. Has anyone done a chemistry analysis of oak wood versus hickory as per chemical bonds. Stronger bonds would be those with fewer impurities. As anything in science, the more you dig deeper, the more a ocean of new things opens up. Archimedes Plutonium www.iw.net/~a_plutonium whole entire Universe is just one big atom where dots of the electron-dot-cloud are galaxies Different kinds of strength are shown here. http://www-materials.eng.cam.ac.uk/m...c/IEChart.html -- - Charles - -does not play well with others |
Fri, 15 Oct 2004 03:53:30 GMT Charles wrote:
Different kinds of strength are shown here. http://www-materials.eng.cam.ac.uk/m...c/IEChart.html -- I was unable to get that site. But I wonder if anyone has offered a math equation for stiffness of wood in relation to strength of wood. If not, then this science area has been neglected and very shabby. If someone has attempted to relate stiffness to strength of wood then this area of science has received due diligence. |
On Sun, 24 Oct 2004 03:15:45 -0500, Archimedes Plutonium
wrote: Fri, 15 Oct 2004 03:53:30 GMT Charles wrote: Different kinds of strength are shown here. http://www-materials.eng.cam.ac.uk/m...c/IEChart.html -- I was unable to get that site. This one may be more easily accessible: http://www.fpl.fs.fed.us/documnts/pdf2001/green01d.pdf But I wonder if anyone has offered a math equation for stiffness of wood in relation to strength of wood. The PDF cited above includes an adequate review of the mathematics of the many stiffness and strength properties that are used to describe wood. Some important points to get from reading that document: Wood is orthotropic: its properties are unique and independent in each of the Cartesian axes and in each shear plane. These properties are very different from species to species, and not all properties vary in the same direction. There are standard measures of these properties, and there are standard methods of measure. In the U.S., the procedures are given in ASTM D143, which any library at an institution with a materials science program should have. Stiffness, or rigidity, denotes elastic resistance to deformation: it applies at loads insufficient to cause permanent deformation or fracture. Strength denotes resistance to loads that cause permanent (plastic) deformation or failure. The two are correlated, but the correlation is only moderate; there is nothing like an equation relating stiffness and strength, nor could there possibly be: the physical mechanisms at work in elastic deformation and plastic deformation of wood are quite different. For example, two important structural woods, Loblolly Pine and Red Oak, differ to quite different degrees in stiffness and strength. They are practically equal in stiffness: modulus of elasticity in bending for Red Oak is 12.5 GPa; for Loblolly Pine, it is 12.3 GPa. But Red Oak is noticeably stronger than Loblolly Pine: modulus of rupture in bending is 99 MPa for Red Oak, but 88 MPa for Loblolly Pine. However, Loblolly Pine is stronger in another important measu modulus of rupture in compression: 49.2 MPa vs. 46.6 MPa. And if you are not yet adequately convinced that there is no exact relation, note that Yellow Poplar, a relatively weak wood in most other properties, is far stronger than either in tension parallel to grain: 154.4 MPa vs. 101.4 MPa for Red Oak. If not, then this science area has been neglected and very shabby. No, it has been well understood for hundreds or thousands of years. Mathematical development, of course, was possible only in the last few centuries. But wood is such an important structural material that it is not at all neglected. Any handbook of building materials and any building code will have extensive data on the strength and permissible loading of various types of wood. If someone has attempted to relate stiffness to strength of wood then this area of science has received due diligence. As indeed it has, and has been for many years. -- Chris Green |
Archimedes Plutonium wrote:
Fri, 15 Oct 2004 03:53:30 GMT Charles wrote: Different kinds of strength are shown here. http://www-materials.eng.cam.ac.uk/m...c/IEChart.html -- I was unable to get that site. But I wonder if anyone has offered a math equation for stiffness of wood in relation to strength of wood. If not, then this science area has been neglected and very shabby. You are a real idiot. In general, strength is most often controlled by defect size and additionally the theoretical treatments (going back to the 1920's) also include elastic modulus (stiffness to you). Something is indeed shabby here. Knowledge? If non-zero. If someone has attempted to relate stiffness to strength of wood then this area of science has received due diligence. -- ................................ Keepsake gift for young girls. Unique and personal one-of-a-kind. Builds strong minds 12 ways. Guaranteed satisfaction - courteous money back - keep bonus gifts http://www.alicebook.com |
Sun, 24 Oct 2004 09:20:41 GMT Christopher Green wrote:
(snipped) This one may be more easily accessible: http://www.fpl.fs.fed.us/documnts/pdf2001/green01d.pdf But I wonder if anyone has offered a math equation for stiffness of wood in relation to strength of wood. The PDF cited above includes an adequate review of the mathematics of the many stiffness and strength properties that are used to describe wood. Some important points to get from reading that document: Wood is orthotropic: its properties are unique and independent in each of the Cartesian axes and in each shear plane. These properties are very different from species to species, and not all properties vary in the same direction. There are standard measures of these properties, and there are standard methods of measure. In the U.S., the procedures are given in ASTM D143, which any library at an institution with a materials science program should have. Stiffness, or rigidity, denotes elastic resistance to deformation: it applies at loads insufficient to cause permanent deformation or fracture. Strength denotes resistance to loads that cause permanent (plastic) deformation or failure. The two are correlated, but the correlation is only moderate; there is nothing like an equation relating stiffness and strength, nor could there possibly be: the physical mechanisms at work in elastic deformation and plastic deformation of wood are quite different. For example, two important structural woods, Loblolly Pine and Red Oak, differ to quite different degrees in stiffness and strength. They are practically equal in stiffness: modulus of elasticity in bending for Red Oak is 12.5 GPa; for Loblolly Pine, it is 12.3 GPa. But Red Oak is noticeably stronger than Loblolly Pine: modulus of rupture in bending is 99 MPa for Red Oak, but 88 MPa for Loblolly Pine. However, Loblolly Pine is stronger in another important measu modulus of rupture in compression: 49.2 MPa vs. 46.6 MPa. And if you are not yet adequately convinced that there is no exact relation, note that Yellow Poplar, a relatively weak wood in most other properties, is far stronger than either in tension parallel to grain: 154.4 MPa vs. 101.4 MPa for Red Oak. If not, then this science area has been neglected and very shabby. No, it has been well understood for hundreds or thousands of years. Mathematical development, of course, was possible only in the last few centuries. But wood is such an important structural material that it is not at all neglected. Any handbook of building materials and any building code will have extensive data on the strength and permissible loading of various types of wood. That is a good website. It may have answered a question brewing in my mind as to whether green treated lumber was stonger than untreated. Since wet lumber is weaker than dry, I suspect green-treated or pressure treated is weaker than untreated, but do not hold me to that speculation. That website would have hit the jackpot for me if it had included the data on Hickory, White Ash, White Oak, BlueSpruce and Honeylocust. Because, if you remember, I hold a grudge between the acclaimed strength of Hickory versus WhiteOak and the **obvious observation of the growth pattern of these trees**. The growth of WhiteOak allows for the limbs to be parrallel to the ground whereas Hickory is upward. That spooky oak look of whiteoak. So the wood would have to be **super strong** to hold that weight. So I need to see some data, Chris, that reconciles the obvious fact that WhiteOak is able to throw limbs out parallel to the ground and hold them there whereas Hickory throws its limbs upward. That report has a reference to a science lab in Pennsylvania. Perhaps they ran hickory and whiteoak and whiteash through their labs? I need to see the data that will reconcile the observation of Whiteoak limbs parallel to ground whereas hickory opts out for a weaker profile. And while I am at it, I need to reconcile the fact that BlueSpruce foliage is so dense yet able to withstand winds must translate into a superior strong wood compared to many others. Again, another reconciliation of observation to numbers data. So can you provide another website that has those numbers for Hickory, WhiteOak, WhiteAsh, Locust and BlueSpruce. Archimedes Plutonium www.iw.net/~a_plutonium whole entire Universe is just one big atom where dots of the electron-dot-cloud are galaxies |
Archimedes Plutonium wrote in message ...
What prompted this question? Well recently I bought some lumber of white ash, plus hickory plus white oak and various others. I do not believe the data on strength of wood is accurate and am wanting to test these woods myself. I believe oak is stronger than hickory. I believe the strength of hickory is a sales hype. The reason I say this is because in history trebuchets were built out of oak and not hickory even though England had hickory species and ash species. And because the growth pattern of oaks allows horizontal branches which means the wood has to be tougher and stronger to grow horizontal. I also want to test spruce for strength because a spruce bears the full force of wind so its wood must be strong. ........................snip...................... ........ Arch, Think first. Oaks grow larger than ash and hickory and therefore were better suited to the construction of trebuchets, and houses and ships for that matter. Testament to the strength of hickory and ash can be found in the traditional preference for these woods in axe handles and carriage frames. (High strength - low weight applications.) BTW. Spruce is preferred for aircraft structure due to its high strength to weight ratio, by dimensional size it is not too strong and quite soft compared to denser woods. Always look for the wisdom inherent in empirical data, it just needs to be interpreted. pragmatist. "While you struggle to cram Theory into your head, Practice sneaks up and bites you on the ass." |
All times are GMT +1. The time now is 07:26 AM. |
Powered by vBulletin® Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
GardenBanter