土弓材料篇翻译.doc

Materials材料 The four materials of the composite cash have their own special properties allowing the bow to function. 四种合成在一起的材料，对于一张弓性能的发挥，有着各自的意义。All four, as most organics, exhibit certain similarities.这四种材料和所有的有机物一样，有着一定的相似性。They are elastic within their ranger of stresses, and strains, but outside this range, all will show plastic (irreversible) deformation before breakage.它们在各自的应力范围内都是有弹性的，而且是紧绷的，一旦超出他们的应力范围，都会在被破坏前从外观显示出不可逆转的变形。This is so called hysteresis which means that once stressed, the materials become a little softer, or less stiff, to show a delay in the recovery from stress.这就是所谓的滞后，意味着一旦拉紧，材料会变得更软，或不太僵硬了，从被拉紧状态恢复时表现出一定的滞后性。An important property of wood, horn and sinew is the greater mechanical strength in one direction: their stiffness is greater in the direction of the fibers as opposed to the cross-direction.木材，筋和角的一个重要作用，就是在一个方向上有着更强大的机械力。当他们方向相向交错的时候，它们在纤维方向上有着更强的刚性。 The mechanical properties of the materials are listed in the table below.材料的力学性能在下面表格里列出。The modulus represents tension for wood, tendons and glue, and compression for horn.弹性模量代表着木材，筋和胶水的张力，而压力代表着角。The date (rounded for clarity) come from my own tests on horn, and also from:被圈起来的数据出自我自己亲自的测试,也来自：D.G. Hepworth, J.P.Smith, “The mechanical properties of composites manufactured from tendon fibres and pearl glue(animal glue)”, Composties: Part A 33(2002),797-803DG赫普沃思，j.p.smith，“复合弓的力学性能来自肌腱纤维和珍珠胶（动物胶）”，复合材料：A部分33（2002），797-803A.Kitchener, “The effect of water on the linear viscoelasticity of horn sheath keratin”, Journal of materials Science Letters, 6(1987),321-322.A基奇纳，“水对角鞘蛋白的线性黏性的影响”，复合材料学报，6（1987），321-322。Kooi,B.W,”On the Mechanics of some Replica Bows”, Journal of the Society of Archer-Antiquaries,1993,36.14-18.Kooi,B.W,，”关于复合弓的机械性“，射手的古文物学会杂志，1993, 36.14-18。The date for hardwood are typical values for wood at this density.在此密度的木材中，这个硬木数据是典型数值。In reality the modulus of elasticity (MOE,stiffness) can range from 1300000 psi for the relatively softer wood of yew to over 2000000 psi for woods like hickry.现实中的弹性模量（MOE，刚度）的范围从1300000PSI的相对较软的木材的红豆杉到2000000 PSI的树林像hickry。 The properties vary depending on the moisture content of the materials which can explain the differences between sources.材料含水量的不同可以作为区分不同材料的一个特点。It is reasonable to say the stiffness of sinew and horn are quite similar at MOE about 2000POa in a bow.这就可以解释为什么在一张弓里，筋和角的硬度模量在2000MPA时很接近。Mixing in glue with sinew does not lower the modulus by much- the dry sinew layer with the concentration of glue at about 50%,has only slightly less stiffness than dry tendons.给筋刷上胶水并不降低太多模量（干筋刷浓度50%的胶水），只是在硬度上比干筋略微软一点。Table of material properties. The values of 4% breaking strain for horn is too low, probably tested at a high rate of loading. 这是材料性能表。在高速加载时，角的断裂应力值太低。It is should be pointed out the materials, and especially the tendon and horn, are so-called viscoelastic.尤其对于筋和角来说，应该说明一下这种所谓的黏粘性。It means that when put under stress quickly, their stiffness is greater than when stressed slowly.这意味着在快速承受外力时，他们的硬度会比慢速承受外力时要更加的硬。This property has important consequences for the archer. The bow will be heavier in weight and will give a faster arrow when drawn and released quickly.对于射手来说这是一个重要的特性。当快速开弓时，弓的拉力会更重，接着快速撒放会让箭飞得更快。This is known to every traditional archer, and is particularly exploited in flight archery.这是传统射手众所周知的事情，尤其在飞箭运动中被广泛运用。The Turks when competing for distance drew the bows by jerking the string for the last few inches to the full draw, a style known as mefruk , while the slashing release is employed for the same purpose today. 土耳其人在远射比赛中，当猛拉弓弦到距离满弓还有几英寸时，会形成一种称为mefruk的风格，直到今日这种鲜明的撒放仍被运用着。Also the stiffness will continually drop when the bows are strained to a greater degree the materials become progressively softer.同时硬度会随着弓被拉满而逐渐递减，因为材料逐渐变软了。For example the sinew tested at strains up to 1%,have the modulus about 2400MPa,while at 5% strain only 1400MPa.例如，筋在拉紧测试到1%的程度时模量有2400MPA，当在5%时只有1400PMA。The materials change their properties a great deal depending on the moisture content.材料的性能会因为含水量的不同而改变很多。Exposed to a new environment, they either dry or take up moisture until equilibrium is reached when they stabilize in the new humidity conditions.在新的环境里，它们或者变干燥，或者在新的湿度下含水量达到平衡而变稳定。For example, at 50% RH(relative humidity ) the materials moisture content is between 12-15%.例如，在50%湿度里，材料的含水量在12-15%。The time needed for an unprotected bow to reach this equilibrium would be about a week.一张未做防护的弓需要一周时间才能达到上述的平衡状态。The stiffness of materials in the new humidity conditions may be quite different.在新的湿度环境里，不同材料的硬度会有很大不同。According to research done on glue, its modulus would raise about two times when dried from 50% to 20%RH.根据对胶水的研究，它的模量会在相对湿度从50%干燥到20%的过程中升高2倍。It is possible the sinew/glue layer would experience similar differences.筋和胶水层都有类似的变化。It is interesting that the drop of stiffness in higher humidity is not gradual or linear-beyond about 75-80%RH the uptake of water becomes much faster.有趣的是材料的硬度在高湿度环境里的下降不是渐变的或线性的，相对湿度超过75-80%含水量会很快提高。This causes the modulus to drop dramatically in the case of glue and probably sinew as well: the modulus of glue at 90%RH only about 1/20 of the modulus at 50%.胶水和筋的特性会引起弹性模量在高湿度情况下明显降低，90%湿度时的弹性模量只相当于50%湿度时模量的1/20。It does not seem to be the case with the horn however-a fully water-logged horn would still retain about 1/2 of dry stiffness.但是角却不是这样的，角在含水量很高的时候弹性是干燥时的1/2.The process of moisture uptake for all materials is somewhat faster than moisture loss during drying.材料吸水的速度要高过干燥时失水的速度。A bow kept in humid weather for a week requires more than a week to dry back to the same low moisture content it had prior to the exposure.一张弓在潮湿的季节里放一周，就需要干燥一周以上的时间才能回到以前干燥环境时的含水量。It has certain consequences for bows used in the field conditions, such as for hunting.弓在一些室外环境里就会这样，例如室外打猎。A whole day outside will not be crased by drying the bow inside overnight, unless the temperature inside has been elevated to hasten the drying as well.弓在外面一整天后，即使放在室内干燥一整夜也无能恢复它的性能，除非室内温度提升的足够高能加速干燥。Horn 角Horn is composed of keratin, one of the major proteins of animal tissue and is present also in hoofs, fingernails, claws, hair and baleen.角是由角蛋白构成，一种动物组织的主要蛋白质，也存在于蹄，指甲，头发和爪子，鲸须。As all proteins, it is made of long chains of protein molecules, combined into a network of spirally bound fibrils.和所有的蛋白质一样，它是由蛋白质分子长链组成，交织成一个螺旋纤维网状结构。The fibrils are mostly oriented along the axis of horn, which gives the mechanical strength and stiffness.角的纤维是沿着角轴线的方向分布，起到机械力和支持强度的作用。Still, horn is quite resistant to stress in the cross direction, since its across-fiber modulus is only half that of the fiber direction.但是，角在横向上也很坚固，因为它的横向纤维模量只有纵向纤维模量的一半。Other keratins, with the exception of baleen, have a random structure and are therefore weaker.其他类型的蛋白质，除了鲸须外，都是无序的结构，所以更脆弱。The horn is exceptionally well suited for the belly of the bows, since it can withstand a great deal of compression, thanks to a very compact structure, held together by chemical bonding between the molecules.角片十分适合弓腹，它能承受很大的压力，因为它结构紧凑，通过分子间的化学键组合在一起。Although it will swell in water to become weaker, it still retains about one half of its dry stiffness when wet.虽然角在水中溶胀会变弱，但仍能保留它干燥时一半的强度。It can be softened in boiling water where some of the chemical bonds break, to be renewed when pressed into a new position upon cooling.角可以再沸腾的水里变软，因为它的化学键会被破坏。当把它放入冷却的环境后就会复原原来特性。Fresh horn taken from an animal contains a lot of water and requires drying for several months before use.从动物身上取下的新鲜角含水量很高，需要干燥几个月才能使用。The best and most common type of horn has always been water buffalo.最好和最常见的角是水牛角。It comes in great lengths and thicknesses and the horns are curved in one plane without twist.水牛角够长够厚，只在一面弯曲还不扭。Turkish bowyers used mostly water buffalo horn and ox horn from a certain district in the country.土耳其弓匠使用的绝大多数水牛角和筋斗取自国内特定的地方。I have experimented with cattle horn for a while as a possible replacement.我曾实验用黄牛角来替代。This horn, however, is too thin walled for heavier bower, is usually twisted and, worst of all, have a tendency to split into layers.这种牛角对于高磅数的弓来说太薄，还容易扭曲，更糟糕的是，有裂开的趋势。This splitting into layers can also occur in the water buffalo, although usually only with strips taken from the inner side of the horns curve.这种开裂在水牛角上也会出现，通常是沿着牛角弧线的内侧。Side to side splitting, such as this, can not be tolerated in the finished strip for the belly of the bow.一边到另一边的开裂，在已经做好的弓腹弧线上是不能承受的。Front to back splits, up to 3in in length and running along the limb, are generally safe.从前面到后面的开裂，即使沿着角的走向开裂了3英寸，也是安全的。The description of horn processing in the Kanis text is somewhere ambiguous. It appears, however, that only material from the outer(longer)side of the horn was used.Kani对角处理的描述不够详实。据说只有角外最长一侧的那面才能用来做弓。The first strip was sliced off this side (kapak-cover),the second, inside(karun-abdomen) strip was cut next, again from the same side of the horn.第一条角片，先从kapak这边切割，第二条从karun这条线切割，接着再次从同样的一边切割。The usual sequence of cutting strips off a whole horn. If the horn is long enough, a third shorter strip can be cut as well.通常是整条切割牛角。如果角够长，第三条稍短的片也能切割出来。It is quite possible the first composite bow was made with ibex horn from Central Asia. Indeed, the early Scythian bow shape is very much like the ibex horns and the bows were most likely built on its base. 世界上第一款复合弓很有可能是来自中亚的山羊角弓。早期的斯基泰弓就是很像山羊角而且很可能就是用山羊角做的。Other goat horn can be used with success, although only very narrow strips can be cut from it, and the strips require heat treatment to remove twist.其他种类的羊角也能做角弓，尽管只能切割出很窄的片，而且这片需要热处理来处理扭曲。 Gemsbok horn is also used, the strips obtained from it are completely straight, however.大羚羊角也可以用，而且角片笔直。My suggestion is to use the buffalo hron, now easy to obtain from South East Asia or Europe.我建议用水牛角，从东南亚或欧洲都容易获得。It is probably most economical for a hobby bowyer to buy whole horns and do the cutting in the shop.对于角弓爱好者来说去商店买整根牛角并切割好是很合算的。This way from two larger horns two or even three pairs of strips can be procured.这样可以从一对大牛角中切割出两对或三对角片。The whole horn is best attached with the hot melt glue to a piece of plywood and the strips cut with a band saw off the outer side one by one as the thickness allows(see my article on ATARN).整个牛角可以用热熔胶站在一块胶合板上再用带锯从外侧一个一个锯出角片。Then the rest of the horn can be used for other projects: tip splices may be a slight twist even in the buffalo horns and one is tempted to follow the twisted surface while cutting to get a wider strip, hoping to make it straight by heat bending.然后剩余的角可以作为它用：角的接头处会有轻微扭曲即使水牛角也如此，要么是沿着扭曲的曲线去切割出更宽的片，然后通过热弯曲来校正。I would avoid it, however, since the strips have a tendency to return to their former twisted position after some time and the bow may become difficult to stabilize.我会避免这么做，因为角片过些日子有恢复到原先扭曲的趋势，而且弓会不稳定。The horn is attacked to a plywood support for the kapak strip to be cut in sequence. Four strips are cut from two horns.牛角被粘在胶合板上来按顺序切割kapak角片。2只角切出了4个角片。One can be tempted to use the side walls of horn as well.角的一个侧面也可以利用。Of course the “grain” of horn or rather the fiber direction is no longer parallel to limbs in such pieces, so the mechanical stiffness would be less and the bow weaker.当然这种角的纹理或纤维走向和切割片的方向不再平行了。所以机械强度较弱，做出的弓也弱。On the other hand, the difference would not be great, since the stiffness of horn would probably drop only by no more than half and the bow could still be perfectly functional.但是，差别不会太大，因为角的强度下降的不到一半，并且做的弓性能仍旧很不错。It should be mentioned that the drop in stiffness for only one layer in the composite does not change the draw weight very much.一片角片的硬度下降对于整个弓的拉力来说改变的不算大。Even if the horn layer was only half as stiff(1/2 modulus), the draw weight would be less by only about 10%.即使角片的硬度下降了1/2，弓的拉力才下降10%。I have made only two bows with side strips and do not have enough experience to comment on this subject.我只做了两张用侧边角片做的弓，并且对这种工艺没足够经验去评测。Much has been made of the use of horns from the same animal as a pair.用来自同一头牛的侧边角片来做成一对角片的事例有很多。I do not see a problem in using horns from different animals, as long as the horns are similar in the curvature and the shape, and also in color for the esthetic reasons.用不同动物的角来做弓都不是问题，只要角的弯曲度和外形相似，并且外观颜色美观就行。Some of the old bows I have seen had nearly transparent horn of amber color.我曾看见旧的弓有琥珀色透明的角片。The white horn exists(much more expensive than the black), but its color is more whitish grey and usually not as transparent.也有白牛角（比黑牛角贵很多），但他的颜色太灰白且通常不够透明。Since these bows were of a later date, I wonder if some kind of bleaching operation was not performed on already white horns to achieve this effect.因为这些旧弓有一定年头了，我猜想这些白牛角不是通过漂白技术做出来的效果。I made a bow once using horn from a supplier who bleached the strips.我曾做过一张弓就用的是漂白过的牛角。The color was very close to the one in old bows, but I have no idea how it was done-white horn turned amber and black to brown.颜色接近那些老弓，但是我不知道使用什么办法，白色的角偏琥珀色，从深色到棕色。I believe the easiest way would be to use the hydrogen peroxide at a higher concentration, since the degradation of the material would be less than with other chemicals, especially with the alkalis.我想最简单的漂白方法是用高浓度过氧化氢，因为它的降解要比其他化学物质缓慢，尤其和碱。In any case, the properties of the bleached horn were very close to the untreated horn (it was a little more brittle) and the bow was functional.漂白过的角和未处理过的角（有点脆）性能接近，做出的弓性能一样。It is also possible the amber-colored horn in old bows came from a different animal, such as the goat.那些琥珀色的旧弓很可能用的是其它动物的角，例如山羊。It should be mentioned selfbows can be made of the horn alone.单体弓可以用角来做。I have seen a white, all-horn bow with reserved tips and nearly straight limbs spliced at the grip in the Topkapi Palace collection.我在Topkapi皇宫博物馆见过一张白色的带着角尖的整只角的单体弓，笔直地弓臂在把手处拼接在一起。There are also Javan bows made of the buffalo horn.那里也有水牛角做的爪洼弓。Given the high specific gravity of horn however, I doubt if the bows performed as well as the selfbows of wood.鉴于单体角弓的高比重，我怀疑它是否能和单体木弓比性能。Sinew 筋The tendons, as well as many other types of tissues, such as skin and bones are composed of collagen a very strong and elastic material, without which the composite bow making would not be possible.筋腱，和皮肤，骨骼等其它组织一样，是由胶原构成，这是一种很强很有弹性的原料，没有它就做不成复合弓。The protein molecules of collagen(made of amino acids) are coiled into left handed helices, which in turn are coiled together into a right-handed helix to form an incredibly stable and resistant rope like network akin to a modern polymer.胶原蛋白的蛋白质分子（由氨基酸）卷成左手螺旋，依次为右旋螺旋盘绕在一起，形成一个非常稳定和抗绳状网络类似于现代的聚合物。The molecules, as well as these protein “yarns” are kept together with so called hydrogen bonds.这些分子，以及这些蛋白质的“线”是所谓氢键保持在一起的。The mechanical properties of the tendons obtained from different animals do not differ much.不同动物的筋腱机械性能差别不大。It is said ox tendons were used for the Turkish war bows and cow tendons for the flight bows.据说公牛筋用于战弓而母牛筋用于飞弓。I doubt if the differences were truly noticeable in a bow.我怀疑这差别在弓里真的很大么？Young animals tendons, however, are lighter in color and a little more flexible.年轻动物的筋颜色更浅而且更柔韧。Also the texture of sinew can vary depending on the species and there are small differences between the tendons taken from the front versus the rear legs.同时腱纹理取决于物种,前面和后面的腿腱有微小差别。The sinew fibres are embedded in the matrix of glue.筋纤维嵌入在基质胶。The combination, as other materials of this type(such as the fiberglass epoxy composites ), resists the fatal breakage better than the solid material.这样的复合物，和其它同类材料一样（例如环氧树脂玻璃纤维复合物），低于外界的破坏力要比固体材料好。It is because if one fiber breaks under tension, the crack that forms across one fiber is immediately stopped by the glue matrix.因为如果一个纤维在拉力下断裂，沿着这个纤维的断裂会立即被胶阵矩停止下来。When the glue, the more brittle material of the two cracks, the crack does not propagate across the laminate, but is skewed along the fibres of sinew leaving the composite unbroken as a whole.此时的胶，两个裂缝中更脆弱的材料，裂缝不会传播到叠层，而是沿着筋的纤维偏离了并保护复合物完好无损。It effectively allows the laminate to strain even further without breakage.它能有效得让叠层拉紧很长且不受损伤。The whitening of the sinew layer on the bows in the stressed areas signifies the development of cracks in the glue and between the glue and the sinew, but not in the sinew itself.弓上的筋层在承力的部位对于胶以及胶和筋之间的断裂的走向有着重要作用，而不在筋自身里。The sinew has an enormous ability to stretch and still return elastically to its former length.筋有巨大的回弹力，可以拉伸并恢复原来长度。The strain at 5-6% brings about only a very small permanent(non-reversible) stretch, and up to 10% strain the permanent drop in the elasticity(in the ability to absorb the energy in the elastic manner) will still be only about 5%.当拉到5-6%时会带来很小的永久性（不可逆）伸张，当高达10%的拉伸时，这不可逆的永久性伸张会仍然保持在5%。Since the strains in a typical bow do not exceed 10%, it means the string follow caused by the sinew will be small.一张弓的拉伸不会超过10%。Many animals have usable tendons. For my first bows I used sinew of ordinary cattle.很多动物的筋都可用。我的第一批弓用的是普通的黄牛筋。I found the cow tendons rather short and greasy, so I then tried moose tendons.我发现奶牛筋太短还油腻，所以我接着用了驼鹿筋。The difference was obvious: much longer, since moose legs are indeed longer, much less grease and the higher strength.差别很明显：筋更长了，因为驼鹿的腿长，油腻也少，更有力量。From then on I have always used moose tendons, which I collect from butchers during the hunting season.从那时起我就坚持使用驼鹿筋，都是我从猎人手里收集到的。图为新鲜的筋挂起来晾干。I do not use backstrap tendons, since they are difficult to procure where I live and I find their texture too rough.我从不用背筋，一是我这里不好弄到，二是纹理粗糙。The leg tendons can be divided into very fine strands of fiber which makes the sinewing job better.腿筋可以撕出很细的丝，更易于铺筋。The neck tendons are too rubbery and weak to be used on a bow.脖子的筋太粗太弱不利于做弓。图为从干燥的筋腱到筋丝。The freshly cut tendons are actually composed of two pieces in the rear leg and of several in the front.新切下的筋腱是前腿的两条和后退的几条。I divide all into separate pieces and remove as much covering tissue as possible.Then I hang the tendons on