Background technology
The enhancing structure of composite or the shape and structure of supporter preform and quality thereof have determined performance of composites substantially.The important form that the high-performance advanced composite material strengthens structure is to adopt the 3 D weaving preform of 3 D weaving technology preparation.Its main feature is: 1. fibre bundle in product, be interweaved, multi-direction orientation, thereby form the structure of an integral body, make product in all directions, particularly on thickness direction, be enhanced, avoided layering.2. can directly knit out three-dimension integrally special-shaped product, for example three-dimension integrally thick-walled tube, cylinder, tapered sleeve body, worker's type beam, T type beam, L type beam, the box type beam etc. of different shape, different size.Need not reprocess the fibre damage of having avoided processing to cause with its composite product of making.3. can use various high-performance fibers, weave as carbon fiber, silicon carbide fibre, quartz fibre, aramid fiber, glass fibre and general fibre etc.Therefore, the 3 D weaving technology is developed in recent years rapidly, and becomes one of crucial technologies of preparing of composite element that high-tech sector is used such as Aeronautics and Astronautics, has good development prospect.
At present the 3 D weaving technology is based on four step rule 3 D weaving technology, and it comes from the four step rule three dimensional knitting method that Luo Ting (R.A.Florentine) not describes in its patent (US 4312261).Li Wei (W.Li) etc. are also at its " structural analysis I of D braided composites preform: the preformed braided technology of four step rule " (textile research, 1990.4.81 page or leaf Structural Analysis of 3-D BraidedPreforms for Composites Part I:The Four-step Preforms, J.Text.Inst., 1990,81 NO.4) square and round four step rule 3 D weaving technology have been described by system in, and have analyzed the characteristics of motion of braiding yarn in the braiding process.This technology can comprise two yarn systems, i.e. knitting yarn wire system and axle yarn system (the 5th to yarn system).Wherein the knitting yarn wire system is the main yarn system, and axle yarn system is the auxiliary yarns wire system that adds as required.All yarns hang along the weaving forming direction and are arranged on the braiding machine chassis.The spread pattern of braiding yarn and type of weave are determined by the shape of cross section of product: 1. the product cross section is rectangle or rectangle combination, for example T type, worker's type, L type, box type etc., the braiding yarn is arranged in the cross sectional shape of product by the row and column mode, and this braid method is the square braiding; 2. the cross section of product is circle or annular, and braiding yarn mode then capable by hoop and radial alignment is arranged in the cross sectional shape of product, and this braid method is called tubular braiding.In the braiding process, braiding machine is pressed the motion of ranks over-over mode, four steps were a braiding machine circulation, knitting yarn is by certain design rule motion, the axle yarn is motionless along weaving direction, form a not stratified three-dimensional four-way (not containing a yarn) or three-dimensional five like this to (containing a yarn) overall structure,, just can be made into the prismatic 3 D weaving preformed member of certain-length through some braiding machine circulations.Zhongcai Sci. ﹠ Tech. Co., Ltd has reported that in its patent " composite with 3 D multi-directional braided fabric dead size reduced profile yarn weaving method " (CN 1614114) a kind of composite is with 3 D multi-directional braided fabric dead size reduced profile yarn weaving method.Its principle is to utilize the characteristics of 3 D weaving spindle (moving yarn and motionless yarn) motion, knitting yarn is constantly reduced or subtracts carefully, thereby realize reducing of braided fabric cross-sectional area.This method can realize the braiding of the three-dimensional braiding preforms that cross-sectional area gradually changes.
In the weaving of basic four step rule uiform section product or reduced profile yarn variable cross-section product, all there is certain force of strain on the yarn, the resultant direction of tension force is vertical with plane, braiding machine chassis all the time on all yarns, therefore the forming direction of preform is continuous in the braiding process and does not change, all the time vertical plane, braiding machine chassis for example weaves the flat board of certain-length or the tapered sleeve body of pipe and cross section gradual change etc.But in engineering was used, the forming direction that a class composite product is arranged also was continuous in the braiding process, but direction changes, and the bending of certain space angle promptly occurs along the length direction of composite.Angle coupling product (referring to Fig. 1) for example, the shape of cross section at product two ends and consistent size, the middle bending that occurs 90 °; Pole product (referring to Fig. 2) for example again, the cross section is a rectangle, 160 ° of bendings appear in the middle part forming direction.For the square preform that this class forming direction appearance bends, the braiding flower joint number amount of bending part should be different to some extent with the arrangement regulation broad ways, and traditional four step rule 3 D weaving is because the tension force effect can't keep spending save smooth even; Pipe bent sub (referring to Fig. 3) for example also, two pipes are oblique, intersection is oval.Existing clean body profiling 3 D weaving technology can only weave continuously and at a pipe on axially, braiding in stays also can't realize oblique.For the composite product of above-mentioned complicated shape structure, can't adopt traditional three dimensional knitting method to finish, can not satisfy the requirement of high-performance composite materials to preformed member.Main solution is to adopt metal material moulding at present, or adopts the method for machining that fibre-reinforced composite further is processed into required form.Obviously, such processing not only can destroy the globality of preform, causes the significant wastage of material and the decline of part performance, and has increased operation, has reduced production efficiency, has improved the manufacturing cost of product.
The specific embodiment
Further narrate the present invention below in conjunction with embodiment and accompanying drawing thereof, the present invention is not subjected to the restriction of embodiment.
A kind of three-dimension integrally braiding method (hereinafter to be referred as braid method) that the weaving forming direction is turned back of the present invention's design, this braid method all weaves by round or square braid method for the constant part of product forming direction, the conventional three-dimensional four-way or five that for example adopts the product requirement is to round or square weaving method braiding, it is characterized in that adopting local braid method for the part that the product forming direction is turned back, promptly at first according to the Changing Pattern of product size with the angle of turning back, design flower nodel line with stitch length for spacing along the weaving forming direction at the product position of turning back, and according to the Design of length of flower nodel line corresponding laterally flower joint number amount and vertical flower joint number amount; Secondly, only part corresponding on the braiding machine chassis being taken the arrangement of yarn device by the horizontal colored joint number amount that designs and vertical flower joint number amount in the braiding process weaves by described Changing Pattern.
Further feature of the present invention is that this braid method adopts three-dimensional four-way or the three-dimensional five local braid methods to round or square to weave the part that the product forming direction is turned back.
The described flower of braid method of the present invention saves, and is meant the minimum repetitive of 3 D weaving preformed member surface yarns interwoven structure.Described stitch length is meant the length of the preformed member that the circulation of braiding machine is knit out.Described weaving forming direction is meant the direction that stitch length forms in the braiding process.Described vertical colored joint number amount is meant along the number of weaving forming direction flower joint.Described horizontal colored joint number amount is meant the number perpendicular to weaving forming direction flower joint.Described colored nodel line is meant that along the weaving forming direction be a series of contours that spacing obtains with the stitch length.
Described local braid method of the inventive method or technology, only be meant that the part that the yarn device arranges is taken on the braiding machine chassis to weave, another part is motionless, formed fabric part yarn is interweaved, and change direction, another part yarn does not interweave, and still presses the braid method that original direction is arranged.
Be example with the braiding process of the oblique pipe joint class product of the right angle box type joint class product of square braiding and tubular braiding respectively below, further describe braid method of the present invention.
The braid method (referring to Fig. 1) of right angle box type joint class product at first is described:
The first, selected weaving forming direction, and arrange and hang the braiding yarn.It is weaving forming direction I that this example is selected the cross-wise direction perpendicular to box type angle coupling product (hereinafter to be referred as box type product), use knitting yarn radical and the 5th to the yarn radical according to this box type product cross sectional dimensions designing institute, the 5th can be according to the designing requirement adding of preform, to improve the mechanical property of product in this direction to yarn.The braiding yarn is arranged in box-like by linescan method or square braid method on the braiding machine chassis, the limit yarn is spaced in the inboard of main body yarn and the outside, and yarn is parallel to the weaving forming direction of product.
The second, the forming direction constant part of braiding product.By box type product or square weaving (referring to Fig. 5) along forming direction take up one's knitting the forming direction constant part or the uiform section part of box type product, until the bending part of box type product.
The 3rd, design flower nodel line.Box type product bending part is divided into two gables or zone by the boundary line B that turns back, the colored nodel line P that every part or zone are parallel to each other for spacing design with a stitch length by separately weaving forming direction, the colored nodel line P1-P4 in two zones and P6-P9 are crossing at the B place, boundary line that turns back.
The 4th, adopt local braid method to weave the bending part of box type product.After the uiform section of box type product has partly woven and has designed colored nodel line, adopt three-dimensional four-way or three-dimensional five to the local braid method of square or the bending part of technology braiding box type product, promptly the local braid method of colored nodel line P1 employing from this example weaves.In part braiding process,, determine that next braiding machine circulation needs the horizontal colored joint number amount of braiding according to the length of each barriness nodel line, it also is yarn columns corresponding on the braiding machine chassis, and making the yarn of this part participate in braiding, remaining yarn still hangs motionless, does not participate in braiding.The different yarn columns of the nodel line correspondence of not suiting, reduces gradually and participates in the yarn columns that weaves to flower nodel line P5 from flower nodel line P1, and the length of flower nodel line is zero during to flower nodel line P5.Finished the part braiding of the B left side, the boundary line delta-shaped region of turning back this moment.The box type product partial rotation an angle of 90 degrees that braiding is good, continuation weaves the Delta Region on the boundary line B the right of turning back, according to the order from P6 to P9, increase the yarn columns of participating in braiding gradually, during to flower nodel line P9 place, all yarns all participate in braiding, and promptly the local weaving forming of the bending part of box type product is finished.
The 5th, braiding box type product remaining part.By the remaining part of second step described method continuation braiding box type product, finish until whole box type product braiding.
Put off until some time later the braiding process (referring to Fig. 3) of bright oblique pipe joint class product below:
The first, selected weaving forming direction, and arrange and hang the braiding yarn.It is weaving forming direction I that this example is selected the pipe cross-sectional direction perpendicular to oblique pipe joint product (hereinafter to be referred as the pipe product).The braiding yarn is arranged in (referring to Fig. 6) on the braiding machine chassis by the tubular braiding method, can add the 5th as required to yarn.
The second, the uiform section part of braiding pipe product.Press the weaving of pipe product, along the take up one's knitting uiform section part of pipe product of described forming direction, up to the intersection area of pipe joint.
The 3rd, design flower nodel line.With the pipe product with the boundary line B separated into two parts of turning back, every part by separately weaving forming direction with a stitch length for spacing designs parallel colored nodel line P, two-part colored nodel line P is intersected at the B place, boundary line that turns back.
The 4th, adopt local braid method to weave the bending part of pipe product.The axis of the two oblique pipes of this example has certain included angle in the space, for guaranteeing the uniformity of pipe product weaving forming, adopts three-dimensional four-way or three-dimensional five to carry out the weaving forming of pipe bending part to round local weaving or method.Basic skills is the length according to each barriness nodel line, determine that next braiding machine circulation needs the horizontal colored joint number amount of braiding, also be yarn columns corresponding on the braiding machine chassis, and make the yarn of this part participate in braiding, remaining yarn still hangs motionless, does not participate in braiding.Because in the tubular braiding, the braiding yarn is arranged in a toroidal on the braiding machine chassis, therefore need select the datum mark of a local braiding on the braiding machine chassis.This datum mark may optionally be on the braiding machine chassis adjacent two row and takes center line between the row of yarn device, the root point (intersection point of initial colored nodel line P and boundary line B) that intersects corresponding to two pipes in this example.With selected part braiding datum mark is the center, determines the pairing yarn arrays of every barriness nodel line symmetrically and takes yarn device position.Reduce the yarn columns of participating in braiding at first symmetrically gradually, carry out the part braiding, finish the braiding of pipe bending part first.Then, the degree angle of the box type product partial rotation designing requirement that braiding is good (this example is 135 degree angles), continue braiding pipe bending part second portion, press opposite order with braiding first, increase the yarn columns of participating in braiding symmetrically gradually, all are taken the yarn device and all participate in braiding on whole circumference, finish till the global formation of pipe intersection area.In general, if bend two parts symmetry that intersects, the each increase of then local braiding is identical with the yarn columns that reduces.
The 5th, braiding pipe product remaining part.Behind the bending part weaving forming of pipe product,, finish until whole pipe product braiding by the remaining part of second step described method continuation braiding pipe product.
Though the shape symmetry of described box type product and pipe product embodiment is regular, braid method of the present invention is equally applicable to the box type class of asymmetric orthogonal or oblique or the braiding of pipe class joint product, has extensive applicability, very strong practicality.
The characteristics of braid method of the present invention are ingenious and have scientifically designed local braid method, thereby the complicated abnormal shape preform that the weaving forming direction is turned back can be formed by the braiding of fibre bundle one-time continuous, avoid the fibre bundle that machining causes behind composite curing damage, guaranteed the continuity and the braided structure globality of reinforcing fiber bundles in the product.According to the preform of the inventive method braiding, its inner reinforcing fiber bundles is woven into the three-dimension integrally network structure, and product is for body formed only, need not reprocessing after making composite, greatly improved the structural integrity and the Mechanics of Machinery character of product, and method is simple, applicability is wide.
The present invention does not address part and is applicable to prior art.
Further provide specific embodiments of the invention below again.
Embodiment 1:
Adopt braid method braiding box type angle coupling product (referring to Fig. 1,5) of the present invention.
The sectional dimension 45*45mm of box type product, each limit thickness is 7mm, adopts four step rule three-dimensional five to weave to square, with the cross-wise direction perpendicular to box type product is weaving forming direction I, braiding yarn 3 is the T300-6K carbon fiber, 22 ° of braid angles, and the required yarn radical of design braiding is 2108.Flower nodel line P1 and above box type product uiform section part adopt traditional square braid method braiding, and promptly all participate in braiding along the yarn of this direction.Flower nodel line P1 divides following left folding transfer part employing the present invention local braid method braiding.Begin stitch length of all yarn braidings to the P2 position from P1, according to the length of flower nodel line P2, the 1/4 yarn row that remain close to the boundary line B that turns back are motionless, and remaining 3/4 yarn row is participated in braiding; Weave a stitch length to the P3 position, the 1/2 yarn row that remain close to the boundary line B that turns back are motionless, and remaining 1/2 yarn row is participated in braiding; Weave a stitch length to flower nodel line P4, the 3/4 yarn row that remain close to the boundary line B that turns back are motionless, and remaining 1/4 yarn row is participated in braiding; When weaving a stitch length to flower nodel line P5, all yarn row are not all participated in braiding.The conversion braiding axle to or direction 90 degree after, continue to adopt the remaining part of turning back of local volume method braiding, braiding pattern is similar with the part braiding of partly turning back partly in a described left side, but the yarn row of participating in braiding are not to reduce gradually but opposite, from flower nodel line P5 0 to 1/4 of flower nodel line P6, the whole yarns row that are increased to P9 place more successively all participation weave.Continue to adopt the remaining box type product uiform section part of traditional square braid method braiding at last, finish until the whole braidings of whole box type product.
In this example, local knitted parts has only 4 stitch lengths, and is longer as compartmentalized box for holding assorted fruits and candies type product bending part, according to the quantity of flower nodel line P institute segmentation, can handle according to said method equally.Be understood that with reference to present embodiment, braid method of the present invention is applicable to the mutual off plumb box of two moulding directions type product.
Embodiment 2:
Adopt braid method braiding pole product (referring to Fig. 2) of the present invention.
The cross section of pole product is a rectangle, size 35*8mm, and braiding adopts three-dimensional five to structure, the square braiding, braiding yarn 3 is the T300-12K carbon fiber, 30 ° of braid angles, the required yarn radical of design braiding is 296.The braiding of the part of bending part is divided into two groups, and 6 times (P1-P3 P5-P7), has yarn all to participate in braiding in the P1 place, weave a stitch length to the P2 place, and the number of threads that participation is woven reduces to 188; Weave a stitch length to the P3 place, the number of threads that will participate in braiding again reduces to 54; Stop (P4 place) after weaving a stitch length; With the product of the finishing angle that the pole product requires of partly turning back, make that knitted parts is not vertical with braiding machine chassis 2.Braiding after the bending takes up one's knitting from P5, has 54 one threads and participates in braiding, but flower joint forming direction difference, weave behind the stitch length to P6 place, and the yarn that participation is woven is increased to 188; Arrive the P7 place after having woven a stitch length, all braiding yarns all participate in braiding.Continue to adopt the remaining pole product uiform section part of traditional square braid method braiding at last, finish until the whole braidings of whole pole product.Surplus with embodiment 1.
Embodiment 3:
Adopt braid method braiding oblique pipe joint product (referring to Fig. 3,6) of the present invention,
Two round tube shape symmetrical configuration of oblique pipe joint product, internal diameter 22mm, external diameter 26mm, space angle is 45 °, adopt four step rule three-dimensional five to structure tubular braiding method, the braiding yarn is the glass fibre of 540tex, 34 ° of braid angles, stitch length is 4.8mm, and the required yarn radical of design braiding is 350.With the vertical tube cross-sectional direction is forming direction I, at first extremely spends nodel line P place with the uiform section part of traditional braid method braiding product pipe; Secondly, according to the pipe partial geometry size of turning back, be spacing with the stitch length, design flower nodel line calculates flower nodel line length and corresponding braiding yarn 3 or takes the quantity of yarn device 1, and concrete quantity is referring to table 1.
The local braiding of table 1 oblique pipe joint product take yarn device (yarn) quantity
Numbering | Flower nodel line length (mm) | Corresponding yarn device or the number of yarns (individual or root) taken |
1 | 69.08 | 350 (50 row * 7 row) |
2 | 61.90 | 308 (44 row * 7 row) |
3 | 52.40 | 266 (38 row * 7 row) |
4 | 46.40 | 238 (34 row * 7 row) |
5 | 42.06 | 210 (30 row * 7 row) |
6 | 38.24 | 196 (28 row * 7 row) |
7 | 34.00 | 168 (24 row * 7 row) |
8 | 27.98 | 140 (20 row * 7 row) |
9 | 17.22 | 84 (12 row * 7 row) |
In the tubular braiding, the braiding yarn is arranged in a toroidal on the braiding machine chassis, has determined the row amount of taking yarn device 1 must be even number by the four step rule braiding characteristics of motion.All taking yarn device 1 quantity is 350, also is 350 braiding yarns 3.In the concrete braiding process, braiding pipe product the last pipe of part of turning back earlier: at first on the braiding machine chassis, select a local datum mark that weaves.This datum mark may optionally be on the braiding machine chassis adjacent two row and takes center line between the row of yarn device, and with its root point (intersection point of initial colored nodel line P and boundary line B) position of intersecting corresponding to two pipes in this example.With selected part braiding datum mark is the center, and according to the order of the numbering 1 to 9 of table 1, required number of yarns of stitch length of every braiding is determined on both sides symmetrically, carries out part and weaves: the first step, and all yarns are all participated in braiding, weave a stitch length; In second step, described local braiding datum mark both sides each 21 (3 row) are taken yarn device 1 and are stopped braiding, and other takes 1 motion of yarn device, weaves a stitch length; In the 3rd step, described local braiding datum mark both sides each 42 (6 row) are taken yarn device 1 and are stopped braiding, and other takes 1 motion of yarn device, weaves a stitch length; In the 4th step, described local braiding datum mark both sides each 56 (8 row) are taken yarn device 1 and are stopped braiding, and other takes 1 motion of yarn device, weave a stitch length, the rest may be inferred, takes yarn device 1 and all stop braiding for 350 on whole circumference, promptly finishes described moulding of going up the pipe part.
Then, the turn back following pipe of part of the box type product partial rotation 135 degree angles braiding pipe products that braiding is good: according to the local braiding of order of the numbering 9 to 1 of table 1: the first step, yarn device 1 is taken in both sides, described center each 42 (6 row), weaves a stitch length, and it is motionless that other takes yarn device 1; In second step, both sides, described center each 70 (10 row) take yarn device 1, weave a stitch length, and it is motionless that other takes yarn device 1; The 3rd step, yarn device 1 is taken in both sides, described center each 84 (12 row), weave a stitch length, it is motionless that other takes yarn device 1, the rest may be inferred, up on the whole circumference 350 take yarn device 1 and all participate in braiding till, promptly finish the moulding of described down pipe part, also promptly finish the turn back moulding of part of whole pipe.Continue pipe uiform section part, up to finishing whole product by basic tubular braiding method braiding product remainder.
Embodiment 4:
Adopt braid method braiding prismatoid product (referring to Fig. 4,5) of the present invention.
The cross section of prismatoid product is a rectangle, holds size 60*8mm greatly, small end size 30*8mm, height 200mm.Adopt the three-dimensional four-way structure of four step rule square weave, the braiding yarn is the T300-12K carbon fiber, and stitch length is 5mm, and the initial required yarn radical of design braiding is 479.Being forming direction perpendicular to the product square-section, adopt local braid method from the big small end of holding, evenly reduce the braiding machine chassis gradually and take the quantity that yarn device 1 (braiding yarn 3) is participated in braiding, gradually reducing a yarn with each stitch length is example, after weaving a stitch length, the number of yarns of participating in braiding reduces 6, finishes up to braiding.To hang the yarn of not participating in braiding then and cut off, promptly finish the integral weaving of prismatoid product from root.
This embodiment explanation, the three-dimensional preform (as described in embodiment 1-3) that braid method of the present invention not only can the weaving forming direction be turned back, and can the weaving forming direction not change, but the three-dimensional preform that shape of cross section changes, as this routine described prismatoid product, the three-dimensional preform that can be called groove or angle that the described product of embodiment 1-3 is made into before the commutation braiding.Although adopt described patented method (CN 1614114) also can weave the product of this type of shape, its technology more complicated, and also the inner yarn of product has broken end, and the globality of goods is undesirable.And the three-dimensional preform that adopts the inventive method to weave, all Yarn breaks all concentrate on the side (circumferentially weaving between the yarn) of product, the inner yarn that strengthens is integral body, do not break end, thereby the globality and the mechanical mechanics property of product itself and then composite have been improved, and method is simple, and is with low cost, is convenient to use.