Processing method for fine selected strip dislocation densified round bamboo products

Abstract

The present invention discloses a processing method for fine-selected strip misaligned densified round bamboo products. The method is as follows: First, design the required specifications and dimensions of the round bamboo products and their building units according to the application scenarios. Use image recognition technology to select bamboo strips with similar vascular bundle gradient distributions, and cut the cross-section of the bamboo strips into bamboo strips similar to isosceles trapezoids. Use the hypotenuse of the trapezoid as the contact surface to form a misaligned joint. Add polypropylene film as an adhesive between the bamboo strips, on the outer surface and inner surface of the round bamboo, and add fiber cloth on the outer surface and inner surface of the round bamboo to form an external binding force to manufacture lightweight and hollow round bamboo products. Based on the gradient structure of the bamboo itself, the present invention uses image recognition technology to finely select strips, improve the similarity of the physical and mechanical properties of the bamboo strips, cut the end faces of the bamboo strips into isosceles trapezoids, and form a misaligned joint to form a locally dense joint, thereby improving the uniformity of the physical and mechanical properties of the round bamboo products.

Description

Technical Field

[0001] The invention belongs to the technical field of round bamboo product processing, and in particular relates to a processing method for round bamboo products with fine strip selection, staggering and densification. Background Art

[0002] As a substitute for wood, bamboo has been widely used in modern production and life. Round bamboo products are an important branch of bamboo processing and utilization. Due to their light weight and high strength, they are widely used in home and construction fields. However, since round bamboo products are made by felling, pruning and shaping bamboo into hollow bamboo stalks, the design performance and application range of round bamboo products are restricted by the basic form and basic physical and mechanical properties of bamboo raw materials. They need to be screened and graded according to their size variability, mechanical properties and appearance quality, which greatly reduces the designability and material utilization rate of round bamboo products.

[0003] Bamboo is a natural composite material composed of thin-walled cells and vascular bundles. It is mainly composed of vascular bundles and thin-walled cell tissues. The vascular bundle is composed of four fiber sheaths surrounding the trachea, with high density and high strength, while the thin-walled cells are hollow and highly brittle materials. After combining with each other, they form a honeycomb-like thin-walled cell tissue with low density and easy to compress. The distribution of vascular bundles is densest on the green side of bamboo and sparsest on the yellow side of bamboo, forming a gradient structure. The mechanical strength of bamboo can be divided into four gradient structures. Among them, gradient A (8) has the highest mechanical strength on the green side of bamboo, with a tensile strength of 350.26MPa. Gradient B (5, 6, 7) has the second highest strength, with an average tensile strength of 283.67MPa. Gradient C (3, 4) has a lower tensile strength again, with an average of 145.67MPa. Gradient D (1, 2) has the lowest tensile strength, with an average of 128.07MPa. The mechanical strength shows a gradient structure from high to low.

[0004] Image recognition technology is a widely used technology in the field of artificial intelligence and is also one of its main research areas. The principle is to find image features based on image features, analyze the content and properties of the image and make judgments, so as to achieve the purpose of identifying the meaning of the image. Use the camera to pre-process the end faces of bamboo strips and find the arrangement pattern of the vascular bundles on the end faces of bamboo materials, and perform noise reduction and defogging on the images to find the characteristics of the arrangement of vascular bundles in bamboo materials, extract the characteristics of the end faces of bamboo materials, and calculate and match bamboo strips with similar arrangement of vascular bundles on the end faces through mathematical models, and obtain bamboo strips with different gradient structures through machine sorting.

[0005] The vascular bundle detection method and device (CN109829879B) discloses identifying the gradient distribution law of vascular bundles, and forming bamboo strips with similar gradient structures after fine classification, thereby realizing scientific, fine and intelligent classification of bamboo strips, reducing the misselection rate, improving work efficiency, increasing material utilization, and stabilizing the physical and mechanical properties of round bamboo products.

[0006] In order to solve the above problems, a processing method for finely selecting staggered and densified round bamboo products was developed. Summary of the invention

[0007] The technical problem to be solved by the present invention is to provide a processing method for round bamboo products with fine selection and dislocation densification in view of the deficiencies of the above-mentioned prior art. The method identifies the gradient distribution law of the vascular bundles in the bamboo strips, and forms bamboo strips with similar gradient structures after fine classification, and cuts the cross section of the bamboo strips into an isosceles trapezoid-like shape, using the inclined surface of the isosceles trapezoid as the gluing surface, and squeezes the low density with high density to form a local dense state, thereby increasing the bonding force. Polypropylene film is used as the adhesive between the bamboo strips, and fiber cloth and polypropylene film are wrapped on the outer and inner surfaces of the round bamboo as the external binding force of the round bamboo products, thereby further increasing its bonding strength, improving its anti-cracking ability and its environmental protection.

[0008] In order to solve the above technical problems, the technical solution adopted by the present invention is: a processing method for finely selected strips, dislocated and densified round bamboo products, characterized in that the method comprises:

[0009] S1. Dimensional design of round bamboo products and their components: According to the demand for structural materials in homes and buildings, the required specifications and dimensions of round bamboo products and their components are designed;

[0010] S2, preparation of standardized bamboo strips: take bamboo and cut it into bamboo sections horizontally, remove the green bamboo, yellow bamboo and inner nodes, and split it vertically into bamboo strips with a width of 2.5 cm, and cut the bamboo strips obliquely relative to the end surface of the horizontal cut into bamboo strips with two specifications of cross-sections similar to isosceles trapezoids, the green bamboo side is the lower bottom surface of the bamboo strip with a cross-section similar to an isosceles trapezoid, and the yellow bamboo side is the upper bottom surface of the bamboo strip with a cross-section similar to an isosceles trapezoid, to obtain a first standardized bamboo strip and a second standardized bamboo strip;

[0011] S3, refined classification of bamboo strips: after scanning the vascular bundles of the transverse section of the first standardized bamboo strip obtained in S2, the transverse section of the first standardized bamboo strip is divided into four partitions, the number and gradient distribution of the vascular bundles in each partition are identified, and after computer matching, the first standardized bamboo strips with high similarity in vascular bundle gradient distribution are classified to obtain first bamboo strips;

[0012] The second standardized bamboo strips obtained in S2 are subjected to the same fine classification as the first standardized bamboo strips to obtain second bamboo strips;

[0013] S4, combining bamboo strips and fiber cloth: laying a single layer of fiber cloth flat, and then laying a polypropylene film with a thickness of 1 mm flat, laying the lower bottom surface of the first bamboo strip with a cross-section similar to an isosceles trapezoid obtained in S3 flat on the polypropylene film at intervals of 1 cm, and then combining them with each other by hot pressing to obtain a combination of the first bamboo strip and the fiber cloth;

[0014] Using the same method of combining the first bamboo strips and the fiber cloth, the second bamboo strips and the fiber cloth obtained in S3 are combined with each other to obtain a combination of the second bamboo strips and the fiber cloth;

[0015] S5, staggered combination of bamboo strips: wrapping the combination of the first bamboo strips and the fiber cloth obtained in S4 onto the surface of the inner mold to form a state where the first bamboo strips are outside and the fiber cloth is inside, and wrapping the polypropylene film on the surface of the combination of the first bamboo strips and the fiber cloth, and then staggering and combining the combination of the second bamboo strips and the fiber cloth obtained in S4 in opposite directions to form a state where the hypotenuse of the first bamboo strip with a cross-section similar to an isosceles trapezoid is combined with the hypotenuse of the second bamboo strip with a cross-section similar to an isosceles trapezoid, to obtain a combination;

[0016] S6, bidirectional hot pressing molding: the assembly obtained in S5 is placed in a cylindrical molding groove between an outer mold and an inner mold, the outer surface of the assembly is heated and extruded by the outer mold, and the inner surface is supported by the inner mold, forming bidirectional extrusion to obtain a round bamboo product.

[0017] Preferably, the moso bamboo in S2 is 4 to 6 years old; the length of the bamboo strips is 100 cm to 400 cm, the thickness is 1.0 cm, and the moisture content is 9% to 12%.

[0018] Preferably, in S2, the lower base width of the cross-section of the first standardized bamboo strip similar to an isosceles trapezoid is 2 cm, the upper base width is 1 cm, and the hypotenuse angle is 60° to 63°; the lower base width of the cross-section of the second standardized bamboo strip similar to an isosceles trapezoid is 2 cm, the upper base width is 1 cm, and the hypotenuse angle is 63° to 65°.

[0019] Preferably, the similarity of the vascular bundle gradient distribution in S3 is 60% to 80%.

[0020] Preferably, the length of the fiber cloth in S4 is the same as the length of the first bamboo strip; the length and width of the polypropylene film are the same as the length and width of the fiber cloth.

[0021] Preferably, the hot pressing in S4 is performed at a temperature of 190° C., a pressure of 4 MPa, and a time of 30 min.

[0022] Preferably, the temperature of the hot extrusion in S6 is 190° C., the pressure is 10 MPa, and the time is 30 min.

[0023] Compared with the prior art, the present invention has the following advantages:

[0024] 1. The present invention is based on the gradient of bamboo materials, and uses image recognition technology to scan the transverse cross-section of bamboo strips and then calculate and classify bamboo strips with similar gradient structures, refine the strip selection, improve the similarity of the physical and mechanical properties of bamboo strips, cut the relative transverse cross-sections of bamboo strips into isosceles trapezoids, and use the characteristics of different densities of bamboo green and bamboo yellow to stagger the combination of the two bamboo strips and fiber cloth, so that the bamboo green squeezes the bamboo yellow to form a local dense joint, and improve the uniformity of the physical and mechanical properties of round bamboo products. In addition, polypropylene film and fiber cloth are used as adhesives and connecting materials between bamboo strips to further enhance the mechanical properties and environmental performance of round bamboo products, prevent round bamboo products from cracking, broaden their designability and improve their dimensional stability.

[0025] 2. The invention proposes to use the gradient structure of bamboo as the basis and remake it into round bamboo products by hot pressing and gluing, which can maximize the use of bamboo raw materials and improve the utilization rate of bamboo. In addition, a light-weight and high-strength structural support material can be formed through a multi-layer composite structure, providing more choices for bamboo home furnishing and bamboo building design.

[0026] 3. The present invention aims to solve the problem that the application of round bamboo products is limited by the large differences in the spontaneous physical and mechanical properties of bamboo. By utilizing technologies such as fine sorting of bamboo strips and staggered combination, round bamboo products with stable structural performance, controllable quality, uniform performance, and strong designability can be produced according to the needs of actual application scenarios, thereby broadening their application in the fields of home and construction.

[0027] 4. The present invention utilizes image recognition technology and vascular bundle distribution as the basis to classify and summarize bamboo strips with similar gradient structures, selects strips in a refined manner, and cuts the strips into isosceles trapezoidal end faces. By utilizing the method of staggered splicing, the problems of easy cracking and low structural strength of hollow round bamboo products are fundamentally solved, the service life of round bamboo products is improved, and the application range is broadened, so that they can be used as furniture structural materials.

[0028] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a schematic diagram of the processing method of the finely selected strips, staggered and densified round bamboo products of the present invention.

[0030] Figure 2 Schematic diagram of the isosceles trapezoidal cross section of the standardized bamboo strips in Example 1 of the present invention.

[0031] Figure 3 Schematic diagram of the isosceles trapezoidal cross section of the standardized bamboo strips in Example 2 of the present invention.

[0032] Figure 4 Schematic diagram of the isosceles trapezoidal cross section of the standardized bamboo strips in Example 3 of the present invention.

[0033] Figure 5 It is a schematic diagram showing that the transverse cross section of the standardized bamboo strip of the present invention is divided into four partitions.

[0034] Figure 6 It is a schematic diagram of the combination of the first bamboo strips and the fiber cloth and the combination of the second bamboo strips and the fiber cloth in embodiment 1 of the present invention, which are staggered and combined with each other in opposite directions.

[0035] Figure 7 It is a schematic diagram of the combination of the first bamboo strips and the fiber cloth and the combination of the second bamboo strips and the fiber cloth in embodiment 2 of the present invention, which are staggered and combined with each other in opposite directions.

[0036] Figure 8 It is a schematic diagram of the combination of the first bamboo strips and the fiber cloth and the combination of the second bamboo strips and the fiber cloth in embodiment 3 of the present invention, which are staggered and combined with each other in opposite directions.

[0037] Fig. 9 It is a schematic diagram of bidirectional hot pressing forming of the combination of the present invention.

[0038] Fig.10 It is a schematic diagram of the processing method of the round bamboo products of the corridor bridge columns in Example 3. DETAILED DESCRIPTION

[0039] Example 1

[0040] The processing method of the fine strip selection, staggered densification round bamboo product of the present embodiment comprises:

[0041] S1. Dimensional design of round bamboo products and their components: According to the requirements of dining table legs, the specifications and dimensions of round bamboo products with an inner diameter of 15 cm and a length of 100 cm are designed;

[0042] S2, preparation of standardized bamboo strips: take 4-year-old bamboo, cut it into bamboo sections horizontally, remove the green bamboo, yellow bamboo and inner nodes, split it vertically into bamboo strips with a length of 100 cm, a width of 2.5 cm, a thickness of 1 cm, and a moisture content of 9% to 12%, and cut the bamboo strips obliquely relative to the end surface of the horizontal cut into bamboo strips with two specifications of cross-sections similar to isosceles trapezoids, the green bamboo side is the lower bottom surface of the bamboo strip with a cross-section similar to an isosceles trapezoid, and the yellow bamboo side is the upper bottom surface of the bamboo strip with a cross-section similar to an isosceles trapezoid, to obtain a first standardized bamboo strip and a second standardized bamboo strip;

[0043] The first standardized bamboo strip has a cross-section similar to an isosceles trapezoid, with a lower base width of 2 cm, an upper base width of 1 cm, and a hypotenuse angle of 63°; the second standardized bamboo strip has a cross-section similar to an isosceles trapezoid, with a lower base width of 2 cm, an upper base width of 1 cm, and a hypotenuse angle of 65° (such as Figure 2 shown);

[0044] S3, bamboo strip fine classification: using the vascular bundle detection method and device (CN109829879B), the transverse section of the first standardized bamboo strip obtained in S2 is scanned for the number of vascular bundles, and then the transverse section of the first standardized bamboo strip is divided into four partitions (such as Figure 5 As shown), the number and gradient distribution of vascular bundles in each partition are identified, and after computer matching, the first standardized bamboo strips with a vascular bundle gradient distribution similarity of 60% are classified to obtain the first bamboo strips;

[0045] The second standardized bamboo strips obtained in S2 are subjected to the same fine classification as the first standardized bamboo strips to obtain second bamboo strips;

[0046] S4, combining bamboo strips and fiber cloth: laying a single layer of fiber cloth, the length of the fiber cloth being the same as that of the first bamboo strip and the width being 48 cm; laying a layer of polypropylene film with a thickness of 1 mm and the same length and width as that of the fiber cloth; laying the lower bottom surface of the first bamboo strip obtained in S3, which is similar to an isosceles trapezoid, on the polypropylene film at intervals of 1 cm, and laying a total of 16 first bamboo strips; and then combining them with each other by hot pressing at a temperature of 190° C., a pressure of 4 MPa, and a hot pressing time of 30 min, to obtain a combination of the first bamboo strip and the fiber cloth;

[0047] The second bamboo strip obtained in S3 and the fiber cloth are combined with each other in the same manner as the first bamboo strip obtained in S3, but the width of the fiber cloth and the polypropylene film is 50 cm (the outer diameter of the round bamboo product is 16 cm), to obtain a combination of the second bamboo strip and the fiber cloth;

[0048] S5, staggered combination of bamboo strips: using an inner mold with a diameter of 15 cm (the surface of which is wrapped with release paper), the combination of the first bamboo strip and the fiber cloth obtained in S4 is wrapped on the surface of the inner mold to form a state where the first bamboo strip is outside and the fiber cloth is inside, and a layer of a polypropylene film with a thickness of 1 mm and a length and width the same as the length and width of the fiber cloth is wrapped on the surface of the combination of the first bamboo strip and the fiber cloth, and then the combination of the second bamboo strip and the fiber cloth obtained in S4 is staggered and combined with each other in opposite directions to form a state where the hypotenuse of the first bamboo strip in cross section is similar to an isosceles trapezoid and the hypotenuse of the second bamboo strip in cross section is combined with each other (such as Figure 6 As shown), the green bamboo side and the yellow bamboo side are squeezed together to obtain a combined body;

[0049] S6, bidirectional hot pressing molding: The assembly obtained in S5 is placed in a cylindrical molding groove with a diameter of 16 cm between the outer mold and the inner mold. The outer surface of the assembly is heated and pressed by the outer mold, and the inner surface is supported by the inner mold to form a bidirectional extrusion (such as Fig. 9 The heat extrusion temperature is 190°C, the pressure is 10MPa, and the time is 30min to obtain a round bamboo product for the dining table legs.

[0050] In this embodiment, the inner mold is a cylindrical mold composed of three sector-shaped bodies, and the outer mold is composed of two concave geometric bodies. The inner mold and the outer mold directly form a cylindrical molding groove.

[0051] After testing, the compressive strength of the round bamboo product of the dining table leg prepared in this embodiment is 60.54MPa, the bending strength is 41.63MPa, and the ring stiffness is 102.33N / mm 2 .

[0052] Example 2

[0053] The processing method of the fine strip selection, staggered densification round bamboo product of the present embodiment comprises:

[0054] S1. Dimensional design of round bamboo products and their constituent units: According to the requirements of roof beams, the dimensions of round bamboo products with an inner diameter of 25 cm and a length of 300 cm are designed;

[0055] S2, preparation of standardized bamboo strips: take 6-year-old bamboo, cut it into bamboo sections horizontally, remove the green bamboo, yellow bamboo and inner nodes, split it vertically into bamboo strips with a length of 300 cm, a width of 2.5 cm, a thickness of 1 cm, and a moisture content of 9% to 12%, and cut the bamboo strips obliquely relative to the end surface of the horizontal cut into bamboo strips with two specifications of cross-sections similar to isosceles trapezoids, the green bamboo side is the lower bottom surface of the bamboo strip with a cross-section similar to an isosceles trapezoid, and the yellow bamboo side is the upper bottom surface of the bamboo strip with a cross-section similar to an isosceles trapezoid, to obtain a first standardized bamboo strip and a second standardized bamboo strip;

[0056] The first standardized bamboo strip has a cross-section similar to an isosceles trapezoid, with a lower base width of 2 cm, an upper base width of 1 cm, and a hypotenuse angle of 60°; the second standardized bamboo strip has a cross-section similar to an isosceles trapezoid, with a lower base width of 2 cm, an upper base width of 1 cm, and a hypotenuse angle of 65° (such as Figure 3 shown);

[0057] S3, bamboo strip fine classification: using the vascular bundle detection method and device (CN109829879B), the transverse section of the first standardized bamboo strip obtained in S2 is scanned for the number of vascular bundles, and then the transverse section of the first standardized bamboo strip is divided into four partitions (such as Figure 5As shown), the number and gradient distribution of vascular bundles in each partition are identified, and after computer matching, the first standardized bamboo strips with a vascular bundle gradient distribution similarity of 70% are classified to obtain the first bamboo strips;

[0058] The second standardized bamboo strips obtained in S2 are subjected to the same fine classification as the first standardized bamboo strips to obtain second bamboo strips;

[0059] S4, combining bamboo strips and fiber cloth: laying a single layer of fiber cloth, the length of the fiber cloth being the same as that of the first bamboo strip and the width being 79 cm; laying a layer of polypropylene film with a thickness of 1 mm and the same length and width as that of the fiber cloth, laying the lower bottom surface of the first bamboo strip obtained in S3, which is similar to an isosceles trapezoid, on the polypropylene film at intervals of 1 cm, laying a total of 27 first bamboo strips; and then combining them with each other by hot pressing at a temperature of 190° C., a pressure of 4 MPa, and a hot pressing time of 30 min, to obtain a combination of the first bamboo strip and the fiber cloth;

[0060] The second bamboo strip obtained in S3 is combined with the fiber cloth in the same manner, but the width of the fiber cloth and the polypropylene film is 82 cm (the outer diameter of the round bamboo product is 26 cm), to obtain a combination of the second bamboo strip and the fiber cloth;

[0061] S5, staggered combination of bamboo strips: using an inner mold with a diameter of 25 cm (the surface of which is wrapped with release paper), the combination of the first bamboo strip and the fiber cloth obtained in S4 is wrapped on the surface of the inner mold to form a state where the first bamboo strip is outside and the fiber cloth is inside, and a layer of a polypropylene film with a thickness of 1 mm and a length and width the same as the length and width of the fiber cloth is wrapped on the surface of the combination of the first bamboo strip and the fiber cloth, and then the combination of the second bamboo strip and the fiber cloth obtained in S4 is staggered and combined with each other in opposite directions to form a state where the hypotenuse of the first bamboo strip in cross section is similar to an isosceles trapezoid and the hypotenuse of the second bamboo strip in cross section is combined with each other (such as Figure 7 As shown), the combination of green bamboo and yellow bamboo squeezed each other to obtain a combined body;

[0062] S6, bidirectional hot pressing molding: The assembly obtained in S5 is placed in a cylindrical molding groove with a diameter of 26 cm between an outer mold and an inner mold. The outer surface of the assembly is heated and pressed by the outer mold, and the inner surface is supported by the mold to form a bidirectional extrusion (such as Fig. 9 The heat extrusion temperature is 190°C, the pressure is 10MPa, and the time is 30min to obtain a round bamboo product for the roof beam.

[0063] After testing, the compressive strength of the round bamboo product of the roof beam prepared in this embodiment is 73.51MPa, the bending strength is 53.86MPa, and the ring stiffness is 111.47N / mm 2 .

[0064] In this embodiment, the inner mold is a cylindrical mold composed of three sector-shaped bodies, and the outer mold is composed of two concave geometric bodies. The inner mold and the outer mold directly form a cylindrical molding groove.

[0065] Example 3

[0066] The processing method of the fine strip selection, staggered densification round bamboo product of the present embodiment comprises:

[0067] S1. Dimensional design of round bamboo products and their components: According to the requirements of the bridge columns, the round bamboo products with an inner diameter of 35 cm and a length of 400 cm are designed;

[0068] S2, preparation of standardized bamboo strips: take 6-year-old bamboo, cut it into bamboo sections horizontally, remove the green bamboo, yellow bamboo and inner nodes, split it vertically into bamboo strips with a length of 400 cm, a width of 2.5 cm, a thickness of 1 cm, and a moisture content of 9% to 12%, and cut the bamboo strips obliquely relative to the end surface of the horizontal cut into bamboo strips with two specifications of cross-sections similar to isosceles trapezoids, the green bamboo side is the lower bottom surface of the bamboo strip with a cross-section similar to an isosceles trapezoid, and the yellow bamboo side is the upper bottom surface of the bamboo strip with a cross-section similar to an isosceles trapezoid, to obtain a first standardized bamboo strip and a second standardized bamboo strip;

[0069] The first standardized bamboo strip has a cross-section similar to an isosceles trapezoid, with a lower base width of 2 cm, an upper base width of 1 cm, and a hypotenuse angle of 60°; the second standardized bamboo strip has a cross-section similar to an isosceles trapezoid, with a lower base width of 2 cm, an upper base width of 1 cm, and a hypotenuse angle of 63° (such as Figure 4 shown);

[0070] S3, bamboo strip fine classification: using the vascular bundle detection method and device (CN109829879B), the transverse section of the first standardized bamboo strip obtained in S2 is scanned for the number of vascular bundles, and then the transverse section of the first standardized bamboo strip is divided into four partitions (such as Figure 5 As shown), the number and gradient distribution of vascular bundles in each partition are identified, and after computer matching, the first standardized bamboo strips with a vascular bundle gradient distribution similarity of 80% are classified to obtain the first bamboo strips;

[0071] The second standardized bamboo strips obtained in S2 are subjected to the same fine classification as the first standardized bamboo strips to obtain second bamboo strips;

[0072] S4, combining bamboo strips and fiber cloth: laying a single layer of fiber cloth, the length of the fiber cloth being the same as that of the first bamboo strip and the width being 110 cm; laying a layer of polypropylene film having a thickness of 1 mm and the same length and width as that of the fiber cloth, laying the lower bottom surface of the first bamboo strip obtained in S3 having a cross-section similar to an isosceles trapezoid on the polypropylene film at intervals of 1 cm, laying a total of 37 first bamboo strips; and then combining them with each other by hot pressing, the hot pressing temperature being 190° C., the pressure being 4 MPa, and the hot pressing time being 30 min, to obtain a combination of the first bamboo strip and the fiber cloth;

[0073] The second bamboo strip obtained in S3 is combined with the fiber cloth in the same manner, but the width of the fiber cloth and the polypropylene film is 113 cm (the outer diameter of the round bamboo is 36 cm), to obtain a combination of the second bamboo strip and the fiber cloth;

[0074] S5, staggered combination of bamboo strips: using an inner mold with a diameter of 35 cm (the surface of which is wrapped with release paper), the combination of the first bamboo strip and the fiber cloth is wrapped on the surface of the inner mold to form a state where the first bamboo strip is outside and the fiber cloth is inside, and a polypropylene film with a thickness of 1 mm and the same length and width as the fiber cloth is wrapped on the surface of the combination of the first bamboo strip and the fiber cloth, and then the combination of the second bamboo strip and the fiber cloth obtained in S4 is staggered and combined with each other in opposite directions to form a state where the hypotenuse of the first bamboo strip in cross section is similar to an isosceles trapezoid and the hypotenuse of the second bamboo strip in cross section is similar to an isosceles trapezoid (such as Figure 8 As shown), the green and yellow bamboos are pressed together to obtain a first layer of bamboo strip-fiber cloth combination;

[0075] Repeat operations S4 and S5 to obtain a second layer of bamboo strips-fiber cloth assembly, the sizes of the fiber cloth and the polypropylene film become 113 cm (inner diameter is 36 cm) and 116 (outer diameter is 37 cm), and the number of the first bamboo strips increases to 39;

[0076] S6, bidirectional hot pressing molding: the first layer of bamboo strip-fiber cloth assembly obtained in S5 is placed in a cylindrical molding groove with a diameter of 36 cm between an outer mold and an inner mold, and the outer surface of the assembly is heated and extruded by the outer mold, and the inner surface is supported by the mold, forming a bidirectional extrusion; the temperature of the hot extrusion is 190° C., the pressure is 10 MPa, and the time is 30 min, to obtain a first layer of cylindrical assembly;

[0077] A 1 mm thick polypropylene film is wrapped on the surface of the first layer of cylindrical assembly, and then the second layer of bamboo strip-fiber cloth assembly is wrapped on the surface of the first layer of cylindrical assembly. After being fixed, it is placed in a cylindrical mold groove with a diameter of 37 cm between an outer mold and an inner mold, and hot-pressed and assembled; the hot-pressing temperature is 190°C, the pressure is 4 MPa, and the time is 20 minutes to obtain a round bamboo product for a corridor bridge column.

[0078] The processing method of the round bamboo products of the bridge column of this embodiment is as follows Fig.10 shown.

[0079] After testing, the compressive strength of the round bamboo product of the roof beam prepared in this embodiment is 103.31MPa, the bending strength is 71.54MPa, and the ring stiffness is 200.58N / mm 2 .

[0080] The above is only a preferred embodiment of the present invention and does not limit the present invention in any way. Any simple modification, change and equivalent change made to the above embodiment according to the technical essence of the invention still falls within the protection scope of the technical solution of the present invention.

Claims

1. A processing method for finely selecting strips and staggering and densifying round bamboo products, characterized in that, the method is as follows: S1. Dimension design of round bamboo products and their constituent units: According to the requirements of structural materials in home and building, design the required specification dimensions of round bamboo products and their building units; S2. Preparation of standardized bamboo strips: Cut the moso bamboo horizontally into bamboo segments, remove the bamboo green, bamboo yellow and inner nodes, and then split them vertically into bamboo strips with a width of 2.5 cm. Cut the end faces of the bamboo strips obliquely relative to the horizontally cut end faces into bamboo strips with cross-sections similar to isosceles trapezoids in two specifications. The bamboo green side is the lower bottom surface of the bamboo strip with a cross-section similar to an isosceles trapezoid, and the bamboo yellow side is the upper bottom surface of the bamboo strip with a cross-section similar to an isosceles trapezoid, obtaining the first standardized bamboo strips and the second standardized bamboo strips; S3. Fine classification of bamboo strips: After scanning the vascular bundles of the transverse cross-section of the first standardized bamboo strips obtained in S2, the transverse cross-section of the first standardized bamboo strips is divided into four zones. Identify the number and gradient distribution of vascular bundles in each zone. After computer matching, classify the first standardized bamboo strips with high similarity in vascular bundle gradient distribution to obtain the first bamboo strips; Perform the same fine classification on the second standardized bamboo strips obtained in S2 to obtain the second bamboo strips; S4. Combination of bamboo strips and fiber cloth: Lay a single-layer fiber cloth flat, and then lay a polypropylene film with a thickness of 1 mm. Lay the lower bottom surface of the first bamboo strips with cross-sections similar to isosceles trapezoids obtained in S3 on the polypropylene film at intervals of 1 cm, and then combine them with each other by hot pressing to obtain a combination of the first bamboo strips and the fiber cloth; Use the same method to combine the second bamboo strips obtained in S3 with the fiber cloth to obtain a combination of the second bamboo strips and the fiber cloth; S5. Staggered combination of bamboo strips and bamboo strips: Wrap the combination of the first bamboo strips and the fiber cloth obtained in S4 on the surface of the inner mold to form a state where the first bamboo strips are on the outside and the fiber cloth is on the inside, and wrap the polypropylene film on the surface of the combination of the first bamboo strips and the fiber cloth. Then, combine the combination of the second bamboo strips and the fiber cloth obtained in S4 in the opposite direction and interleave them to form a state where the hypotenuses of the first bamboo strips with cross-sections similar to isosceles trapezoids are combined with the hypotenuses of the second bamboo strips with cross-sections similar to isosceles trapezoids to obtain a combination; S6. Bidirectional hot pressing and forming: Put the combination obtained in S5 into the cylindrical molding groove between the outer mold and the inner mold. The outer surface of the combination is heated and extruded by the outer mold, and the inner surface is supported by the inner mold to form a two-way extrusion to obtain round bamboo products.

2. The processing method for finely selecting strips and staggering and densifying round bamboo products according to claim 1, characterized in that, the moso bamboo in S2 is 4 - 6 years old; the length of the bamboo strips is 100 cm - 400 cm, the thickness is 1.0 cm, and the moisture content is 9% - 12%.

3. The processing method for finely selecting strips and staggering and densifying round bamboo products according to claim 1, characterized in that, The lower base width of the cross-section of the first standardized bamboo strip similar to an isosceles trapezoid described in S2 is 2 cm, the upper base width is 1 cm, and the oblique angle is 60° - 63°; the lower base width of the cross-section of the second standardized bamboo strip similar to an isosceles trapezoid described in S2 is 2 cm, the upper base width is 1 cm, and the oblique angle is 63° - 65°.

4. A processing method for a fine-strip selection and dislocation densification round bamboo product according to claim 1, characterized in that the similarity of the high similarity of the vascular bundle gradient distribution described in S3 is 60% - 80%.

5. A processing method for a fine-strip selection and dislocation densification round bamboo product according to claim 1, characterized in that the length of the fiber cloth described in S4 is the same as the length of the first bamboo strip; the length and width of the polypropylene film are the same as the length and width of the fiber cloth.

6. A processing method for a fine-strip selection and dislocation densification round bamboo product according to claim 1, characterized in that the temperature of the hot pressing described in S4 is 190 °C, the pressure is 4 MPa, and the time is 30 min.

7. A processing method for a fine-strip selection and dislocation densification round bamboo product according to claim 1, characterized in that the temperature of the heat extrusion described in S6 is 190 °C, the pressure is 10 MPa, and the time is 30 min.

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