CN109318506B

CN109318506B - Composite material net frame type lattice structure and preparation method thereof

Info

Publication number: CN109318506B
Application number: CN201810855315.2A
Authority: CN
Inventors: 张建华; 官成宇; 孙科; 杨浩; 周恩惟; 高硕颀; 张安康; 王宁州
Original assignee: Harbin Engineering University
Current assignee: Harbin Engineering University
Priority date: 2018-07-31
Filing date: 2018-07-31
Publication date: 2020-11-10
Anticipated expiration: 2038-07-31
Also published as: CN109318506A

Abstract

The invention belongs to the field of composite materials, and discloses a composite material net frame type lattice structure and a preparation method thereof, wherein the composite material net frame type lattice structure comprises a transverse truss, a longitudinal truss and a skin; the longitudinal truss is inserted in the inner part of the transverse truss, the transverse truss is inserted in the groove of the longitudinal truss, and the skin is bonded with the outer sides of the transverse truss and the longitudinal truss. The transverse truss comprises a transverse upper chord member, a transverse lower chord member and a transverse web member; the transverse upper chord and the transverse lower chord are parallel to each other, the transverse web member is connected between the transverse upper chord and the transverse lower chord, and the transverse web member, the transverse upper chord and the transverse lower chord form a triangle. The longitudinal truss comprises a longitudinal upper chord member, a longitudinal lower chord member, longitudinal web members, grooves and foam; the groove is positioned at the joint of the longitudinal web member at the outer side of the longitudinal truss and the connection of the longitudinal upper chord member and the longitudinal lower chord member and the midpoint of the two joints. The invention has the advantages of high production efficiency, good maintainability, high node strength and strong connectability.

Description

Composite material net frame type lattice structure and preparation method thereof

Technical Field

The invention belongs to the field of composite materials, and particularly relates to a composite material net frame type lattice structure and a preparation method thereof.

Background

The lattice structure consists of two panels and a lattice core in the middle, wherein the lattice core consists of periodically arranged rod pieces. The lattice core rod pieces can be divided into forms of pyramids, tetrahedrons, Kagome and the like according to the arrangement mode of the lattice core rod pieces. Materials can be classified into metals, composite materials, plastics, and the like. The metal lattice structure typically joins the core and the panel together by welding. Due to the special property of the composite material, the lattice structure of the composite material cannot be welded and can only be connected in modes of cementing, mechanical connection, fiber embedding and the like.

The lattice structure of the composite material is prepared by the following methods: (1) the drawing connection method comprises the steps that a pressure rod groove and a drawing hole are formed in a panel, a pressure rod is inserted into the pressure rod groove, then drawing wires pre-impregnated with resin are woven from the drawing hole to penetrate through the panel, and the upper panel and the lower panel which are opposite to each other are pulled and fixed; (2) the water cutting assembly method comprises the steps of cutting a laminated plate into corrugated strips through a water cutting process, processing embedding and locking notches at nodes, embedding and locking the strips together in a cross mode to prepare a pyramid lattice core, and finally bonding the strips with the plate; (3) the method comprises the steps of (1) cutting an interlocking notch on a panel, inserting a dot matrix core rod piece cut by water into the interlocking notch of the panel, and coating glue; (4) the corrugated plate is cut into a lattice core and reinforced by a metal sheet at a node, firstly, the composite material corrugated plate is prepared, then, the composite material corrugated plate is cut into a zigzag rod piece, then, the corrugated rod piece and the metal sheet are assembled and bonded together, and finally, the metal sheet is bonded with a panel; (5) the assembly method of the pultrusion rod comprises the steps of punching a hole in a panel, inserting a cylindrical rod prepared by pultrusion, coating structural adhesive on nodes, curing and cutting off redundant parts; (6) the thermoplastic fusion bonding method comprises the steps of weaving a thermoplastic ribbon prepreg into a mesh fabric, then locally heating and stamping to obtain a dot matrix structure core material, and finally heating and bonding the core material and two thermoplastic composite material panels; (7) the mould hot-pressing secondary molding process is characterized in that a one-way fiber reinforced composite pyramid lattice core is prepared through a mould and then is bonded with a panel; (8) the mould hot-pressing one-step forming process comprises the steps of using a detachable core mould, laying prepreg in a groove of the core mould, and embedding fibers at two ends into a panel; (9) the fiber-inserted low-melting-point alloy core mold resin injection method comprises the steps of inserting fibers which are not soaked with resin into a low-melting-point alloy core mold with holes, paving panel fibers, injecting resin by using a VARI process, curing, and heating to melt the low-melting-point alloy core mold.

The preparation method of the lattice structure of the composite material has the following problems: in the method (1), wire drawing can only be pulled but not pressed, and meanwhile, the wire drawing molding lacks die pressure and is unstable in quality; in the method (2), the surface cores are bonded for the second time, the joints at the bonding joint are easy to damage, in addition, the fiber direction of the laminated plate cannot be designed, and the transverse fiber content of the rod piece is large; the methods (3) to (7) are surface-core secondary bonding, and the bonding position of the node has low strength; the method (8) has complex mould and difficult demoulding, and is difficult to be applied to actual engineering; the core and the panel are integrally formed by the method (9), the structural mechanical property is good, the problem of demoulding is solved, and the ultra-large special-shaped curved surface member can be prepared, but the preparation process is complex and the production cost is high.

Although the preparation methods of the lattice structures are different, the structural forms are the same, namely: the two panels are connected together by a middle dot matrix core, and the core and the panels are in point contact. Under the classical three-point bending stress state, the lattice core in the structure mainly bears shearing force and simultaneously keeps the panel stable, and the panel mainly bears bending moment. The lattice core needs to transfer shear to the panel at one point, which results in severe stress concentrations on the panel. Meanwhile, the panel is very sensitive to damage, and the bearing capacity of the lattice structure is reduced due to the damage of any panel. Two panels are not available, so that the interior of the lattice structure is difficult to maintain later. How to promote the connection between the core and the face plate and the stress concentration of the face plate at the nodes are major problems faced by lattice structures.

Disclosure of Invention

The invention aims to disclose a composite material net frame type lattice structure with uniform stress distribution and high node strength and a preparation method thereof.

The purpose of the invention is realized as follows:

a composite material net frame type lattice structure comprises a transverse truss 1, a longitudinal truss 2 and a skin 3; the longitudinal truss 2 is inserted in the inner part of the transverse truss 1, the transverse truss 1 is inserted in the groove 7 of the longitudinal truss 2, and the skin 3 is bonded with the outer sides of the transverse truss 1 and the longitudinal truss 2.

The transverse truss 1 comprises a transverse upper chord 41, a transverse lower chord 51 and a transverse web member 61; the transverse upper chord 41 and the transverse lower chord 51 are parallel to each other, the transverse web member 61 is connected between the transverse upper chord 41 and the transverse lower chord 51, and the transverse web member 61, the transverse upper chord 41 and the transverse lower chord 51 form a triangle.

The longitudinal truss 2 comprises a longitudinal upper chord 42, a longitudinal lower chord 52, longitudinal web members 62, grooves 7 and foam 22; the upper longitudinal chord 42 and the lower longitudinal chord 52 are parallel to each other, the longitudinal web member 62 is connected between the upper longitudinal chord 42 and the lower longitudinal chord 52, and the longitudinal web member 62, the upper longitudinal chord 42 and the lower longitudinal chord 52 form a triangle; the groove 7 is positioned at the joint of the longitudinal web member 62 at the outer side of the longitudinal truss 2 and the longitudinal upper chord 42 and the longitudinal lower chord 52 and the midpoint of the two joints; the width of the groove 7 is the same as the thickness of the transverse truss 1, the depth of the groove 7 at a node is the same as the height of the section at the node where the transverse web member 61 of the transverse truss 1 is connected with the transverse upper chord 41 and the transverse lower chord 51, and the depth of the groove 7 at the midpoint of the two nodes is the same as the height of the sections of the transverse upper chord 41 and the transverse lower chord 51 of the transverse truss 1; the foam 22 covers the outer sides of the upper and lower

longitudinal chords

42 and 52 of the longitudinal girders 2.

A preparation method of a composite material net frame type lattice structure is characterized by comprising the following steps: comprises the following steps:

the method comprises the following steps: preparing a mold, and fixing the core mold 8 on the base 15;

step two: winding and inserting truss rod piece fibers, winding and inserting triangular fibers 9, a first trapezoidal fiber 10, a second trapezoidal fiber 11 and a third trapezoidal fiber 12 onto a core mold 8, pressing the core mold to the bottom, and paving three trapezoidal fibers by using a continuous trapezoidal fiber 13;

step three: laying surface layer fibers 14 and foam 22, wherein the foam 22 is only laid on the longitudinal truss section 19 or not according to the actual use condition;

step four: installing the end seal 16, and closing the L-shaped mold 17, using mechanical compression or vacuum bag compression;

step five: curing and molding, namely curing by using a constant temperature heating box or an autoclave if prepreg is used, and preparing by using an RTM (resin transfer molding) or VARTM (vacuum transfer molding) or VARI (vacuum infiltration molding) process if resin-free fibers are used;

step six: removing the die, and respectively preparing a transverse truss section 18 and a longitudinal truss section 19 according to the steps;

step seven: forming a groove 7 on the surface of the longitudinal truss profile 19 by using a milling machine;

step eight: slicing the transverse truss section 18 and the longitudinal truss section 19 to obtain a transverse truss 1 and a longitudinal truss 2;

step nine: inserting the longitudinal truss 2 into the transverse truss 1 which is horizontally staggered left and right in a left-right inclined mode, performing sand blasting treatment before insertion, and coating structural adhesive;

step ten: aligning the staggered transverse trusses 1, erecting the inclined longitudinal trusses 2, and inserting the transverse trusses 1 into the grooves 7 of the longitudinal trusses 2 to obtain a composite material net frame type lattice structure;

step eleven: the skin 3 is bonded.

The invention has the beneficial effects that:

the invention has high production efficiency and is suitable for industrialized mass production; the stress is reasonable, the internal truss is a main bearing component and a panel; the maintainability is good, and the influence on the structure stress caused by the panel dismantling is small; the rod piece fiber completely penetrates through the node, the fiber at the node is continuous, and the node strength is high; the connectability is strong, and only the connection of the truss rod pieces needs to be considered when the truss type lattice structure is connected with other plane lattice structures.

Drawings

FIG. 1 is a schematic diagram of a composite material lattice structure;

FIG. 2 is a schematic view of the connection of the transverse girders and the longitudinal girders;

FIG. 3 is a composite material lattice structure unit;

FIG. 4 is a plan view of a transverse truss;

FIG. 5 is a plan view of the longitudinal truss;

FIG. 6 is a plan view of a longitudinal truss with foam;

FIG. 7 is a preparation mold;

FIG. 8 is a schematic view of fiber winding and insertion laying;

FIG. 9 is a schematic view of triangular fiber insertion of a truss;

FIG. 10 is a schematic view of a first truss ladder fiber penetration;

FIG. 11 is a schematic view of a second truss ladder fiber insertion;

FIG. 12 is a schematic view of the third truss trapezoidal-shaped fiber penetration;

FIG. 13 is a schematic view of the insertion of all truss fibers;

FIG. 14 is a schematic view of a continuous interpenetrating trapezoidal shaped fiber;

FIG. 15 is an exploded view of the mold assembly;

FIG. 16 is a mold close view;

figure 17 is a schematic view of longitudinal truss profile grooving;

FIG. 18 is a schematic view of a longitudinal truss section cut;

FIG. 19 is a schematic view of a transverse truss section cut;

FIG. 20 is a schematic view of the longitudinal truss insertion direction;

FIG. 21 is a schematic view of longitudinal truss insertion;

FIG. 22 is a first assembled view;

FIG. 23 is a second assembled view;

FIG. 24 is a third assembled view;

FIG. 25 is a fourth assembly view;

FIG. 26 is a fifth assembly view;

fig. 27 is a sixth assembly view.

Detailed Description

The invention is further described below with reference to the accompanying drawings:

referring to fig. 1, a lattice structure of a composite material lattice frame includes a transverse truss 1, a longitudinal truss 2 and a skin 3; as shown in fig. 2 and 3, the longitudinal girders 2 are inserted into the inner parts of the transverse girders 1, the transverse girders 1 are inserted into the grooves 7 of the longitudinal girders 2, and the skin 3 is bonded to the outer sides of the transverse girders 1 and the longitudinal girders 2.

As shown in fig. 4, the transverse truss 1 comprises a transverse upper chord 41, a transverse lower chord 51 and a transverse web member 61; the transverse upper chord 41 and the transverse lower chord 51 are parallel to each other, the transverse web member 61 is connected between the transverse upper chord 41 and the transverse lower chord 51, and the transverse web member 61, the transverse upper chord 41 and the transverse lower chord 51 form a triangle.

As shown in fig. 5, the longitudinal truss 2 comprises a longitudinal upper chord 42, a longitudinal lower chord 52, a longitudinal web 62, a groove 7 and foam 22; the upper longitudinal chord 42 and the lower longitudinal chord 52 are parallel to each other, the longitudinal web member 62 is connected between the upper longitudinal chord 42 and the lower longitudinal chord 52, and the longitudinal web member 62, the upper longitudinal chord 42 and the lower longitudinal chord 52 form a triangle; the groove 7 is positioned at the joint of the longitudinal web member 62 at the outer side of the longitudinal truss 2 and the longitudinal upper chord 42 and the longitudinal lower chord 52 and the midpoint of the two joints; the width of the groove 7 is the same as the thickness of the transverse truss 1, the depth of the groove 7 at a node is the same as the height of the section at the node where the transverse web member 61 of the transverse truss 1 is connected with the transverse upper chord 41 and the transverse lower chord 51, and the depth of the groove 7 at the midpoint of the two nodes is the same as the height of the sections of the transverse upper chord 41 and the transverse lower chord 51 of the transverse truss 1; as shown in fig. 6, the foam 22 covers the outer sides of the upper and lower longitudinal chords 42 and 52 of the longitudinal girders 2.

step (1): as shown in fig. 7, a mold is prepared, and the core mold 8 is fixed to the bed 15;

step (2): winding and inserting the truss rod fiber, winding and inserting the triangular fiber 9, the first trapezoidal fiber 10, the second trapezoidal fiber 11 and the third trapezoidal fiber 12 on the core mold 8, and pressing the fibers to the bottom as shown in fig. 8 to 13, wherein three kinds of trapezoidal fibers are laid by using one continuous trapezoidal fiber 13;

and (3): laying surface layer fibers 14 and foam 22, wherein the foam 22 is only laid on the longitudinal truss section 19 or not according to the actual use condition;

and (4): the end seal 16 is installed as in fig. 15 and 16 and the L-shaped mold 17 is closed and pressurized using mechanical or vacuum bag;

and (5): curing and molding, namely curing by using a constant temperature heating box or an autoclave if prepreg is used, and preparing by using an RTM (resin transfer molding) or VARTM (vacuum transfer molding) or VARI (vacuum infiltration molding) process if resin-free fibers are used;

and (6): removing the die, and respectively preparing a transverse truss section 18 and a longitudinal truss section 19 according to the steps;

and (7): as shown in fig. 17, grooves 7 are formed on the surface of the longitudinal truss profile 19 by using a milling machine;

and (8): as shown in fig. 18 and 19, the transverse truss profile 18 and the longitudinal truss profile 19 are sliced to obtain the transverse truss 1 and the longitudinal truss 2, and the transverse truss (1) and the longitudinal truss (2) can be prepared by pultrusion, flat plate cutting and 3D printing.

And (9): as shown in fig. 20, 21 and 22, the longitudinal girders 2 are obliquely inserted into the horizontal girders 1 which are horizontally staggered from left to right, and sand blasting and structural glue are applied before insertion;

step (10): as shown in fig. 22 to 27, aligning the staggered transverse trusses 1, erecting the inclined longitudinal trusses 2, and inserting the transverse trusses 1 into the grooves 7 of the longitudinal trusses 2 to obtain a composite material lattice structure;

step (11): the skin 3 is bonded.

Example 1 is given below: and (3) fiber winding and inserting method:

if the transverse truss shown in fig. 4 is manufactured, the truss length is 240mm, and the truss is composed of 4 basic unit bodies, wherein the length of each unit body is 60mm, the angle of each web member is 45 degrees, the section of each web member is 2mm x 2mm, the distance between the upper surface and the lower surface of each chord member is 32mm, and the section of each chord member is 2mm x 3 mm.

The longitudinal truss 2 is shown in fig. 5, the length of the truss is 240mm, and the truss is composed of 4 basic unit bodies, each unit body has the length of 60mm, the angle of a web member is 36.25 degrees, the section of the web member is 2mm x 2mm, the distance between the upper surface and the lower surface of a chord member is 32mm, the section of the chord member is 2mm x 6mm, a groove at a node is 2.1mm x 3.5mm, and a groove at the middle part of the chord member is 2.1mm x 3.1 mm.

Step (1): and (4) preparing a mould. As shown in fig. 7, the truss profile preparation mold comprises a base 15 and nine core molds 8, wherein the core molds 8 are fixed on the base 15 by bolts or other methods, and gaps of 2mm are left between the core molds 8. The contour of the core mold 8 is triangular, and corresponding chamfers are required to be designed at corners of the triangle according to the overlapping amount of the node fibers and the demolding requirement. In order to facilitate demoulding, the core mould 8 is designed to be detachable, and in addition, a Teflon coating layer can be prepared on the surface of the core mould 8, and a breathable layer and a heat shrinkable tube are sequentially wrapped on the surface of the core mould. The transverse truss and the longitudinal truss need to use core moulds 8 with different sizes according to the design, and the preparation principle of the transverse truss and the longitudinal truss is the same, and only the layer and the size are different.

Step (2): and winding and inserting the truss rod piece fibers. As shown in fig. 8, the fiber is wound around the core mold 8 from the upper opening of the core mold 8, and the wound fiber is pressed to the bottom of the core mold 8 in the direction of the arrow shown in the figure. The core mold 8 needs to be wound with 4 kinds of fibers, i.e., a triangular fiber 9, a first trapezoidal fiber 10, a second trapezoidal fiber 11, and a third trapezoidal fiber 12. As shown in fig. 9, the winding insertion track of the triangular fiber 9 is formed by winding and inserting the triangular fiber 9 along the number sequence in the circle, and the track is a periodic triangle. Fig. 10 to 12 show winding insertion trajectories of the first trapezoidal fiber 10, the second trapezoidal fiber 11, and the third trapezoidal fiber 12, respectively, and the trajectories are periodic trapezoidal. Fig. 13 is a layout of all fibers except the triangular fibers 9. The 3 ladder fibers may be wound along the path shown in fig. 14 using only one continuous ladder fiber 13. The laying proportion of the triangular fibers 9 and the trapezoidal fibers 13 is laid according to calculation. When the fiber is laid, the fiber bundle is as small as possible, and the fiber is laid uniformly for many times, so that a large amount of fibers with the same path are prevented from being laid at one time. The fiber tows may be prepregs and may be unsized fibers.

And (3): laying surface layer fibers 14 or foam 22. As shown in fig. 8, 13 and 14, after the triangular fibers 9 and the trapezoidal fibers 13 are laid, the surface fibers 14 are wound on the outer layer. A certain amount of 90 degree fibers may be added to the surface fibers 14 to increase the rod's transverse strength. Instead of laying the surface fibers 14 directly in their entirety, the longitudinal girders 2 may alternatively be laid with foam 22 instead of a portion of the surface fibers 14. As shown in fig. 5, the longitudinal girder 2 is provided with grooves 7, so that the fibers are broken at the nodes, and the strength at the nodes is weakened, so that part of the surface fibers 14 can be replaced by the foam 22 as shown in fig. 6. The method can reduce the weight of the structure without reducing the strength of the truss. Replacing the 2mm thick skin fibers 14 with foam 22 as shown in fig. 6 can reduce the weight of the longitudinal girders 2 by 26.2% and 17.4% of the total weight.

And (4): and (5) closing the mold. As shown in fig. 15 and 16, the end seal 16 is first installed, and then the L-shaped die 17 is installed. Mechanical pressing or vacuum bag pressing may be used.

And (5): and (5) curing and forming. If the prepreg is used, the prepreg is cured and molded by using a constant temperature heating box or an autoclave. If the fiber is not impregnated, the fiber is formed by using RTM or VARTM or VARI process.

And (6): and (6) removing the mold. The outermost L-shaped mold is removed first, and then the connection between the core mold 8 and the base 15 is released, and the base 15 is removed. Finally the core mould 8 is extracted and the end seal 16 is removed. If the core mold 8 is externally wrapped with the ventilation layer and the heat shrinkable tube, air may be injected into the ventilation layer first, and then the core mold 8 may be pulled out.

And (7): the longitudinal truss profile 19 is surface grooved. The transverse truss profile 18 does not require a surface treatment, whereas the longitudinal truss profile 19 requires the use of a milling machine to provide the grooves 7 in the surface. As shown in fig. 17, the milling cutter 20 mills a rectangular groove 7 in the surface of the longitudinal truss profile 19. The width and depth of the groove 7 are determined according to the node section and chord section of the transverse truss 1, and in order to ensure smooth assembly, the assembly tolerance needs to be designed, and the groove depth and width are increased by 0.1 mm.

And (8): and (5) cutting the section into slices. The transverse truss section 18 and the longitudinal truss section 19 were cut into a sheet of 2mm thickness using a cutting blade 21 as shown in fig. 18 and 19, and the transverse truss 1 and the longitudinal truss 2 were obtained.

And (9): the longitudinal girders 2 are inserted. As shown in fig. 20, the transverse girders 1 are arranged upside down by odd-even difference, shifted in the left-right direction by 22.4mm, that is, 0.37 cycle length, and at a fixed distance of 30mm in the front-rear direction, that is, 0.5 cycle length. The longitudinal girders 2 are perpendicular to the transverse girders 1, are inverted up and down according to different parity and are inclined at an angle of 45 degrees left and right, and the bottom spacing is 5.9mm, namely 0.1 cycle length. The longitudinal girders 2 are inserted into the transverse girders 1 in the direction of the arrows shown in fig. 20, and the insertion is shown in fig. 21. As shown in fig. 22, which is a front view of the process, viewed in the direction of the longitudinal girders 2, it can be seen that the transverse girders 1 and the longitudinal girders 2 do not geometrically interfere. The grooves 7 and the truss joints are sandblasted before insertion and structural glue is applied to the grooves 7 and the corresponding joints of the longitudinal girders 2.

Step (10): and assembling the truss. As shown in fig. 23, the lower chord groove 7 of the longitudinal girder is inserted into the lower chord 5 of the lateral girder 1, and then the staggered lateral girders 1 are gradually moved to the flush position as shown in fig. 23 to 27, in the process of which the angle of the longitudinal girder 2 is changed as the lateral girders 1 are moved. Finally, as shown in fig. 27, the transverse girders 1 are aligned side-to-side and the longitudinal girders stand upright. And obtaining a finished product of the truss lattice structure shown in figure 1 after the structural adhesive is cured.

Step (11): and (6) bonding the skin. And (3) coating structural adhesive on the surfaces of the upper chord and the lower chord of the truss type lattice structure, and then adhering a skin 3 to the surface to obtain the composite material truss type lattice structure with the skin shown in figure 2.

Example 2: a pultrusion forming method:

the preparation of the transverse truss sections 18 and the longitudinal truss sections 19 was performed using a pultrusion method instead of the steps (1) to (7) in example 1. The subsequent assembly steps were the same as in example 1.

Example 3: plate cutting method:

the preparation of the lateral girders 1 and the longitudinal girders 2 was performed using a flat plate cutting method instead of the steps (1) to (8) in example 1. A 2mm thick composite laminate or metal plate is directly cut into the transverse girders 1 and the longitudinal girders 2 as shown in fig. 4 and 5 using water cutting or laser cutting or mechanical cutting. The subsequent assembly steps were the same as in example 1.

Example 4: 3D printing method:

the preparation of the transverse girders 1 and the longitudinal girders 2 was performed using a composite 3D printing technique instead of the steps (1) to (8) in example 1. Printing was performed along the fiber path shown in fig. 14 using composite 3D printing techniques. The method can be used for efficiently producing the high-performance composite material net frame type lattice structure. And the material utilization rate is high, and the material can be effectively saved. The subsequent assembly steps were the same as in example 1.

Compared with the prior art, the invention has high production efficiency and is suitable for industrial batch production; the stress is reasonable, the internal truss is a main bearing component and a panel; the maintainability is good, and the influence on the structure stress caused by the panel dismantling is small; the rod piece fiber completely penetrates through the node, the fiber at the node is continuous, and the node strength is high; the connectability is strong, and only the connection of the truss rod pieces needs to be considered when the truss type lattice structure is connected with other plane lattice structures.

The above description is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A composite material net frame type lattice structure is characterized in that: comprises a transverse truss (1), a longitudinal truss (2) and a skin (3); the longitudinal truss (2) is inserted in the transverse truss (1), the transverse truss (1) is inserted in the groove (7) of the longitudinal truss (2), and the skin (3) is bonded with the outer sides of the transverse truss (1) and the longitudinal truss (2).

2. A composite lattice structure of the grid type as set forth in claim 1, wherein: the transverse truss (1) comprises a transverse upper chord member (41), a transverse lower chord member (51) and a transverse web member (61); the transverse upper chord (41) and the transverse lower chord (51) are parallel to each other, the transverse web member (61) is connected between the transverse upper chord (41) and the transverse lower chord (51), and the transverse web member (61), the transverse upper chord (41) and the transverse lower chord (51) form a triangle.

3. A composite lattice structure of the grid type as set forth in claim 1, wherein: the longitudinal truss (2) comprises a longitudinal upper chord (42), a longitudinal lower chord (52), longitudinal web members (62), grooves (7) and foams (22); the longitudinal upper chord (42) and the longitudinal lower chord (52) are parallel to each other, the longitudinal web member (62) is connected between the longitudinal upper chord (42) and the longitudinal lower chord (52), and the longitudinal web member (62), the longitudinal upper chord (42) and the longitudinal lower chord (52) form a triangle; the groove (7) is positioned at the joint of the longitudinal web member (62) at the outer side of the longitudinal truss (2) and the longitudinal upper chord (42) and the longitudinal lower chord (52) and the midpoint of the two joints; the foam (22) covers the outer sides of the longitudinal upper chord (42) and the longitudinal lower chord (52) of the longitudinal truss (2).

4. A composite lattice structure of the grid type as set forth in claim 1, wherein: the width of the groove (7) is the same as the thickness of the transverse truss (1), the depth of the groove (7) at the node is the same as the section height of the node where the transverse web member (61) of the transverse truss (1) is connected with the transverse upper chord (41) and the transverse lower chord (51), and the depth of the groove (7) at the midpoint of the two nodes is the same as the section height of the transverse upper chord (41) and the transverse lower chord (51) of the transverse truss (1).

5. A composite material net frame type lattice structure and a preparation method thereof are characterized in that: comprises the following steps:

the method comprises the following steps: preparing a mold, and fixing a core mold (8) on a base (15);

step two: winding and inserting truss rod piece fibers, winding and inserting triangular fibers (9), first trapezoidal fibers (10), second trapezoidal fibers (11) and third trapezoidal fibers (12) onto a core mold 8, pressing the core mold to the bottom, and paving three kinds of trapezoidal fibers by using one continuous trapezoidal fiber (13);

step three: laying surface layer fibers (14) and foam (22), wherein the foam (22) is only laid on the longitudinal truss section (19) or not according to the actual use condition;

step four: installing an end seal (16), closing the mold with an L-shaped mold (17), and applying pressure using a mechanical press or a vacuum bag;

step six: removing the die, and respectively preparing a transverse truss section (18) and a longitudinal truss section (19) according to the steps;

step seven: a milling machine is used for forming a groove (7) on the surface of the longitudinal truss section bar (19);

step eight: slicing the transverse truss section (18) and the longitudinal truss section (19) to obtain a transverse truss (1) and a longitudinal truss (2);

step nine: inserting the longitudinal truss (2) into the transverse truss (1) which is horizontally staggered left and right in a left-right inclined mode, performing sand blasting treatment before insertion, and coating structural adhesive;

step ten: aligning the staggered transverse trusses (1), erecting the inclined longitudinal trusses (2), and inserting the transverse trusses (1) into the grooves (7) of the longitudinal trusses (2) to obtain a composite material net frame type lattice structure;

step eleven: and bonding the skin (3).