CN106515023B - A kind of metal sutures connection method with composite material - Google Patents

Abstract

The invention relates to a suture connection method between metal and composite material, and belongs to the field of connection of dissimilar materials. The connection method includes the following steps: firstly, processing neatly arranged transparent slots on the part where the metal part is pre-connected to the composite material; secondly, roughening the surface of the contact area where the metal part is pre-connected to the composite material thirdly, the fiber pre-impregnated with resin or dry fiber is stuffed into the slot hole, the composite material preform is overlapped with the metal part, and fixed with a clamp; fourthly, the suture is pulled through the metal part with a needle The slots and composite material preforms are sequentially stitched through adjacent slots. Finally, the fixture is removed, and then the connecting piece is put into the forming mold for integral curing and molding. The suture connection method of the present invention can greatly improve the connection strength between the metal and the composite material due to the introduction of the Z-direction suture, not only the weight of the connection parts is light, but also no stress concentration will be caused.

Description

A kind of suture connection method of metal and composite material

technical field

The invention relates to the field of connection of dissimilar materials, in particular to a method for connecting a resin-based composite material component and a metal material component by using a sewing technique.

Background technique

At present, there are two main methods for connecting metal and composite materials, namely adhesive bonding and mechanical bonding. Adhesive bonding refers to the process of connecting two glued parts by using the mechanical bonding force, physical adsorption force and chemical bonding force generated by the adhesive on the connecting surface. The stress distribution of the parts connected by adhesive bonding is continuous, light in weight, and the process method is simple, but the bonding strength is low, and it is generally suitable for parts with small transfer loads. Mechanical connections are suitable for parts that transmit higher loads or emphasize reliability. Mechanical connection refers to the process and method of connecting parts with fasteners. Commonly used mechanical fasteners mainly include bolts, screws and rivets. Although the mechanical connection method is fast, on the one hand, it increases the weight of the part, on the other hand, it needs to punch holes in the metal and composite material parts, which easily leads to stress concentration.

Contents of the invention

Aiming at the deficiencies in the prior art, the technical problem to be solved by the present invention is to propose a method for suture connection of metal and composite material, which is different from the existing adhesive and mechanical connection methods in that it utilizes suture thread Through the thickness direction of the composite material preform and the metal part containing the slot hole, the metal part and the composite material part are stitched and bound together, and finally the connector is obtained through integral curing molding. Compared with the bonding technology, the method of the invention can improve the shearing resistance between metal and composite material layers due to the introduction of Z-direction sutures, thereby greatly improving the connection strength between metal and composite materials. Compared with the traditional mechanical connection, it not only reduces the weight of the connected parts, but also avoids the phenomenon of stress concentration.

The technical solution proposed by the present invention to solve the technical problem of the connection method is to design a method for suturing and connecting metal and composite materials, the connecting method comprising the following steps:

First of all, neatly arranged transparent slots are processed on the part where the metal parts are pre-connected with the composite material. The slots are slender strips. The length is designed to be equal to or greater than the distance between the first and last rows of sutures (that is, the number of rows minus one and then multiplied by the row spacing), the number of slots is designed to be the number of stitches per row, and the center spacing of the slots is designed to be pre-stitched Pitch.

Second, surface roughness modification is performed on the contact area where the metal part is pre-coincided with the composite material connection.

Thirdly, fibers pre-impregnated with resin or dry fibers are used to fill the slot holes so that the fiber volume content in the slot holes is higher than 30%. Place the composite material preform (laminated fabric raw material or prepreg) and the metal part on top of each other, and clamp and fix the metal part and the composite material preform with a clamp so that no relative movement occurs.

The fixture has neatly arranged slots intersecting the direction of the slots of the metal parts at the position where the metal part and the composite material part overlap. The slots are slender and the length direction of the slots is designed It is greater than or equal to the distance between the first and last stitches of stitching (that is, the number of stitches minus one and then multiplied by the pitch), the width of the slot is designed to be less than or equal to 50% of the pre-stitching line spacing, and the number of slots is designed to be stitched. The number of rows, the center spacing of the slots is designed to be the prestitched row spacing.

Fourth, use a sewing needle to pull the suture through the metal slot and the composite material preform, and suture along the direction of the slot of the jig, pass through the adjacent slots in turn, and stitch the needle eye between the slot of the jig and the metal slot. Hole location where holes intersect. Stitches are performed in the number of design rows to bind the metal part to the composite preform.

Finally, the fixture is removed, and the metal and composite suture joints are put into the forming mold to be solidified, and the molded part is taken out after curing.

The fineness of the suture yarn in the thickness direction of the connector should be controlled within 800tex, which can be high-performance fibers such as aramid fiber, glass fiber or carbon fiber. The fineness of the yarn should be moderate. If the yarn is too thin, the connection strength cannot be greatly improved. If the yarn is too thick, it will cause a large resin-rich area in the composite material, thereby reducing the in-plane strength of the composite material.

The center-to-center distance of the metal part slots is determined by the stitch pitch of the pre-stitching, which is equal to one stitch pitch.

The length of the slot hole of the metal part is equal to or greater than the distance between the first and last lines of pre-stitching, that is, the number of lines minus one and then multiplied by the line spacing.

The width of the slot hole of the metal part is designed to be less than or equal to half of the needle pitch. If the width is too narrow, the sewing needle cannot pass through smoothly. If the width is too wide, the distance between the two slots will be lost, which will reduce the bonding area between the metal and the composite material, thereby reducing the connection strength; in addition, if the slot is too wide, the metal parts will easily deform during processing.

The corners at both ends of the metal component slots should be chamfered to prevent stress concentration in the slots.

The technology of roughening the surface of metal parts is an existing technology.

The material of the jig should have a thinner thickness, thereby shortening the stroke of the suture needle and the suture thread. The material of the jig should be relatively rigid and not easily deformed, and can be stainless steel, aluminum alloy, bakelite, nylon, etc.

The center-to-center distance of the two slotted holes of the fixture is determined by the stitching row spacing, which is equal to a row spacing.

The width of the fixture slot should not be too wide, it should be wider than the diameter of the sewing needle, otherwise it is not conducive to the passage of the sewing needle; and the width should be less than half of the suture line spacing, otherwise, the slot width is too large, which will easily cause Deformation of the fixture.

The fastening and positioning methods of the fixture are prior art.

The sewing process of the present invention belongs to the prior art, and can adopt machine sewing technology or manual sewing technology.

The reason why a certain number of slots are excavated at the overlapping parts of the metal parts of the fixture and the composite parts, instead of hollowing out all the fixtures, is because: on the one hand, the fence structure formed by the slots of the fixture can block the metal slots. The pre-impregnated fiber or dry fiber filled in the hole is removed from the slot; on the other hand, the length direction of the slot of the fixture can guide the sewing direction of each row, and the hole formed by the intersection of the slot of the metal part and the slot of the fixture is just the seam The position where the needle should penetrate can play a guiding role in the way of manual suture, so as to control the stitch distance and line distance more accurately.

Although the method of the present invention punches holes on the metal parts, before the composite material is solidified, the slot hole is filled with prepreg fiber or dry fiber. During the solidification process of the composite material, the resin has fluidity, and under the action of molding pressure, The resin flows into the slots of the metal parts and forms a composite material with the filled fibers. After curing, it will bond with the side walls of the slots of the metal parts, which can effectively transfer loads without stress concentration.

The method of the present invention skillfully uses the barrier structure formed by the slot holes of the fixture, which not only prevents the filled prepreg fiber or dry fiber from being pushed out under the action of the friction force of the sewing needle and the suture on the filler, but also forms The hole position intersecting with the metal slot hole can be used as a mark of the insertion position of the suture needle and guide the suture. It is not only suitable for machine suture, but also suitable for manual suture.

The connection method of the present invention, on the one hand, produces a bonding effect in the process of integral molding at the contact parts of the metal material part and the composite material part; Realization, good connection performance and other advantages.

Description of drawings

Fig. 1 is a schematic diagram of the relative positions of the connection between the aluminum plate and the composite material plate according to the embodiment of the present invention.

Fig. 2 is a schematic diagram of the positions of the slots on the aluminum plate of the embodiment of the present invention.

Fig. 3 is a schematic diagram of the structure of the fixture according to the embodiment of the present invention.

Fig. 4 is a schematic diagram of the scale line corresponding to the position of the center line of the metal hole on the outer surface of the lower side panel according to the embodiment of the present invention.

Fig. 5 is a schematic diagram of filling small pieces of prepreg into the holes of the aluminum plate according to the embodiment of the present invention.

Fig. 6 is a schematic diagram of the suture state during the suturing process of the embodiment of the present invention

Fig. 7 is a schematic diagram of the front effect of the aluminum plate and the composite material plate after suture connection according to the embodiment of the present invention.

Fig. 8 is a schematic diagram of the rear surface effect of the aluminum plate and the composite material plate after suture connection according to the embodiment of the present invention.

Fig. 9 is a schematic diagram of the structure of the molding die of the embodiment of the present invention.

Detailed ways

Further describe the present invention below in conjunction with embodiment and accompanying drawing thereof:

The following is a connection process for connecting an aluminum plate 100 with a length of 150 mm, a width of 100 mm, and a thickness of 4 mm and a composite material plate 200 of the same size using the connection method of the present invention, wherein the raw material of the composite material plate 200 is a laminated carbon fiber reinforced ring Oxygen resin prepreg. The length of the connecting overlapping area is 35 mm, and the relative positions of the aluminum plate 100 and the composite material plate 200 are shown in FIG. 1 . The overlapping areas are pre-connected by suturing. Pre-suture along the width direction of the two parts, the number of suture lines is 4, each line has 10 stitches, the stitch distance is 10mm, and the row distance is 8mm. The specific suture connection steps are as follows:

Firstly, slotting is carried out in the area 300 where the aluminum plate is previously overlapped with the composite material plate by machining, and a total of 10 transparent hollow slots 110 are processed, as shown in Figure 2, the slot spacing is 10mm, and the slot width is 2mm , the groove length is 24mm. The two ends of the slot are rounded with a radius of 1 mm.

Second, roughen the surface of the area surface 300 where the aluminum plate is pre-overlapped and in contact with the composite material plate by means of mechanical grinding.

In the following steps, an aluminum alloy fixture 400 is applied, which is processed from an aluminum plate with a thickness of 8mm. The structure of the fixture 400 is shown in Figure 3. It consists of two upper and lower panels 401 and 402. The cavity of the upper side panel 401 410 is used to embed the aluminum plate 100 , and the cavity 420 of the lower side panel 402 is used to embed the composite material plate 200 .

The upper side panel 401 of the clamp has a positioning groove 411, and the lower side panel 402 has a positioning block 421. Its function is that, on the one hand, the positioning block 421 is embedded in the positioning groove 411 and can be used for positioning the relative positions of the upper and lower side panels. On the other hand, positioning Block 421 may position the aluminum plate 100 .

There are four transparent slots 431 and 432 in the upper and lower panels 401 and 402 of the fixture corresponding to the overlapped area 300 of the aluminum plate and the composite material plate. The length direction of 432 is the pre-sewing path of the suture thread, and is perpendicular to the direction of the slot 110 of the aluminum plate.

The fixture structure is shown in Figure 3.

The lower side panel 402 is also marked with a scale line 422 corresponding to the center line of the metal aluminum plate slot 110 in the outer slotted area, as shown in FIG. 4 .

The specific operation of the third step is to put the prepreg composite material plate 200 that has been laminated to a predetermined thickness into the cavity 420 of the lower side panel 402 . Then, put the aluminum plate 100 into the area surrounded by the positioning block 421 on the lower side panel 402 to align the relative positions of the aluminum plate 100 and the composite material plate 200 .

Fourth, fill the pre-laminated carbon fiber prepreg blocks with a size of 23 mm×4 mm×1.5 mm into the 10 slots of the aluminum plate 100 , as shown in FIG. 5 . Then the upper side panel 401 and the lower side panel 402 of the fixture are clamped and fastened.

The 5th, adopt the aramid fiber yarn of 158tex as the sewing thread 600 to penetrate the sewing needle 500, and use the sewing needle 500 to pull the sewing thread 600 to penetrate from the point 721 where the slot hole of the lower side panel intersects with the scale line (as shown in Figure 4 shown), pass through the intersection 711 of the slot 431 of the upper panel 401 and the slot of the metal panel, and leave a 8mm thread end 601 outside the prepreg of the lower panel, and then insert the sewing needle through the slot of the upper panel 401 The intersection point 712 with the metal panel slot is threaded and pulled out from the position of the lower side panel 722 . Then the sewing needle penetrates from the position of the intersection 723 of the scale adjacent to the slot and the slot of the clamp and then passes out from the position of the upper side panel 713 . The schematic diagram of the suture state during the suture process is shown in Figure 6. Constantly thread the sewing needle into the adjacent position and pull out the suture until the line is sewed up. At last, the thread end 601 of about 8mm is left at the lower side panel slot hole head end to complete the sew up of the first line. Finish the rest of the rows in the same way as the first row.

Sixth, after all the sutures are completed, the clamp 400 is removed, and the front effect of the aluminum plate 100 and the composite material plate 200 after the suture connection is shown in FIG. 7 , and the rear effect is shown in FIG. 8 . At this time, there will be thread ends 601 for each row of seams on the back, and the function of the thread ends 601 is to prevent the seams from retracting into the prepreg. Finally, the joint is placed into the mold 800 for curing. The schematic diagram of the mold 800 is shown in FIG. 9 . After curing and opening the mold, the molding of the composite material is completed and the connection with the aluminum plate is also completed. At this time, the suture head is flatly embedded on the surface of the composite material without protrusions.

Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than limit the protection scope of the claims. Although the present invention has been described in detail with reference to the embodiments, those skilled in the art should understand that non-essential modifications or equivalent replacements to the technical solution of the present invention cannot depart from the essence of the technical solution of the present invention, and should be included in the rights of this application. within the scope of protection required.

Claims (3)

1. A metal and composite material suture connection method, the connection method comprising the following steps: first, the metal part is pre-processed to the position where the composite material is connected to a neatly arranged transparent slot hole, the slot hole is an elongated strip shape, The width of the slot is designed to be less than or equal to 50% of the stitch pitch, and the length of the slot is designed to be equal to or greater than the distance between the first and last lines of suture (that is, the number of lines minus one and then multiplied by the line spacing), the number of slots The design is the number of stitches per row, and the center spacing of the slot holes is designed as the stitch pitch of the pre-stitching; second, the surface roughness modification is performed on the contact area where the metal part is pre-joined with the composite material; third, the pre-impregnated Fibers with resin or dry fibers are stuffed into the slots, and the composite material preform (laminated fabric raw material or prepreg) is overlapped with the metal part, and the metal part and the composite material preform are clamped and fixed with a clamp , so that no relative movement occurs, the fixture has neatly arranged slots intersecting with the direction of the slots of the metal parts at the position where the metal part and the composite material part overlap. The direction of the slot, the length of the slot is designed to be greater than or equal to the distance between the first and last stitches of stitching (that is, the number of stitches minus one and then multiplied by the stitch distance), and the width of the slot is designed to be less than or equal to 50% of the pre-sewing line spacing, The number of slots is designed as the number of stitching rows, and the center spacing of the slots is designed as the row spacing of stitching; fourth, use a sewing needle to pull the suture through the metal slot and the composite material preform, and pass through the adjacent slots in turn hole, and stitched according to the number of rows designed, so that the metal part and the composite material preform are stitched and bound together; finally, the clamp is removed, and the metal and composite material stitched joints are put into the forming mold for integral curing. After curing Remove the part from the mold. 2. A method of seaming and connecting metal and composite materials as claimed in claim 1, characterized in that the amount of fibers filled in the slots on the metal parts should be such that the fiber volume content in the slots is higher than 30%. 3. A method for suturing metal and composite materials as claimed in claim 1, wherein the suture is sewed along the direction of the slot of the jig, and the eye of the suture is at the intersection of the slot of the jig and the slot of the metal.