CN111305380B

CN111305380B - Aluminum alloy rectangular pipe latticed shell joint based on linear friction welding and connecting method thereof

Info

Publication number: CN111305380B
Application number: CN202010226410.3A
Authority: CN
Inventors: 杨大彬; 李明锦; 柳锋; 孙祥义
Original assignee: Shandong Jianzhu University
Current assignee: Shandong Jianzhu University
Priority date: 2020-03-27
Filing date: 2020-03-27
Publication date: 2021-06-22
Anticipated expiration: 2040-03-27
Also published as: CN111305380A

Abstract

The invention discloses an aluminum alloy rectangular pipe reticulated shell node based on linear friction welding and a connection method thereof. The connecting method is used for connecting the latticed shell nodes. According to the invention, by introducing the protective cover, the high-strength bolt cannot be influenced by the inner flash generated when the sealing plate and the rectangular pipe are subjected to friction welding, the protective cover has a limiting effect on the nut, when the high-strength bolt is screwed into the bolt table, the high-strength bolt is not limited by the pin, and cannot slide into the rectangular pipe, so that a sliding groove does not need to be formed on the high-strength bolt, and the overall structural strength is high.

Description

Aluminum alloy rectangular pipe latticed shell joint based on linear friction welding and connecting method thereof

Technical Field

The invention relates to a net shell node of a space grid structure and a connecting method thereof.

Background

The space grid structure is mainly a steel structure, and the main node forms of the space grid structure are bolt connection nodes and welding nodes. In the bolt connection node, usually, the spout is carved with along the axis direction on the bolt surface, utilizes sleeve, pin and spout cooperation jointly with the screw in the internal portion of node of excelling in, nevertheless because the pin probably destroys because of receiving the shearing in the screw in-process, causes the high strength bolt and can not screw up, this is the phenomenon of "false twisting" that traditional rack bolt connection node ubiquitous. There is also a document that proposes a new node form in which the pin is not sheared during screwing. However, the high-strength bolts are generally provided with sliding grooves and are matched with pins to prevent the high-strength bolts from sliding into the rod before being screwed into the node body. And the processing of the sliding groove is labor-consuming and time-consuming.

In the bolt connection node, the rod piece is connected with the node body through a high-strength bolt. To the individual layer steel latticed shell structure of rectangle member, member tip and shrouding are connected, and the screw rod of high strength bolt is worn out through the shrouding trompil from the member is inside, then is connected with the node body. The connection between the sealing plate and the rod is generally realized by traditional fusion welding, and the welding seam strength can be as strong as that of the parent metal.

Compared with steel, the aluminum alloy has the advantages of light weight, corrosion resistance, low temperature resistance, convenient processing and the like. As a new building structure material, aluminum alloy structures have been increasingly applied to the building fields of sports, exhibitions, chemical industry and the like, and are particularly suitable for large-span space grid structures with high maintenance cost or long-term exposure to humid and corrosive or low-temperature environments. In the last decade, the aluminum alloy space grid structure enters the rapid development stage in China, and most of the structural systems are single-layer latticed shells formed by connecting H-shaped or rectangular section rods by plate-type nodes. At present, the bolt connection node containing the sealing plate and having certain application in the single-layer steel latticed shell structure is hardly applied to the aluminum alloy latticed shell structure, and the reason is that when the aluminum alloy rod and the sealing plate are connected by adopting the traditional fusion welding, the weld strength of the aluminum alloy rod and the sealing plate is reduced to about half of that of an aluminum alloy base metal, so that the utilization of the rod strength is greatly influenced.

In a conventional plate type node, upper and lower flanges of a rod piece with an H-shaped section or a rectangular section are connected with upper and lower node plates through fastening bolts, and a web plate is not connected with the node. The node mainly has the following defects: in order to meet the stress requirement, the number of fastening bolts is large, so that the construction is complicated; the distance between the upper node plate and the lower node plate is a fixed value, so that the section heights of all the rod pieces in the structure need to be uniform, and the rod pieces with smaller stress cannot fully exert the material strength; the web and the node are not connected, so that the section of the rod piece at the node is weakened, more importantly, the shearing resistance of the rod piece at the node is very low, in the practical engineering, the node which is sheared greatly is often solved by replacing the rod piece with a steel member, and because the thermal expansion coefficients of steel and aluminum alloy are greatly different, the local replacement has certain adverse effects on the mechanical property, the material uniformity, the corrosion resistance, the low temperature resistance and the like of the structure.

The linear friction welding technology is a novel, high-quality, high-efficiency and environment-friendly solid phase connection technology, and can weld metals with rectangular, polygonal and other sections, materials which cannot be welded by a traditional welding method and dissimilar metals. The linear friction welding process can be completely and automatically controlled by welding equipment, the reliability is high, and the heat in the welding process is concentrated on a friction interface, so that a heat affected zone of a welding joint is narrow, the welding efficiency is high, and the welding joint with the strength equal to or basically equal to that of base metal can be obtained. Meanwhile, the linear friction welding process is clean in environment, welding wires do not need to be filled, protective gas does not need to be added, and the process is a green process. However, at present, the linear friction welding technology is not applied to the aluminum alloy space grid structure.

Disclosure of Invention

The technical problem to be solved by the invention is as follows: the aluminum alloy rectangular pipe latticed shell node based on linear friction welding is provided, so that the structural strength of the node is high, and the connecting method of the aluminum alloy rectangular pipe latticed shell node based on linear friction welding is provided.

In order to solve the technical problem, the aluminum alloy rectangular pipe reticulated shell node based on linear friction welding comprises a rectangular pipe, a sealing plate and a bolt platform, wherein the sealing plate is connected with the bolt platform through high-strength bolts, the high-strength bolts comprise nuts, prism sections and threaded rod sections which are sequentially connected into a whole, the rectangular pipe and the sealing plate are made of aluminum alloy, at least two high-strength bolts are rotatably inserted into the sealing plate, the nuts of all the high-strength bolts are positioned on the same side of the sealing plate, sleeves which are sleeved by the threaded rod sections and matched with the prism sections are arranged on the prism sections of the high-strength bolts, the sleeves are connected with the prism sections through pins, the sleeves are in threaded connection with the pins, holes for connecting the pins on the prism sections are round holes, the nuts are covered with protective covers fixed on the sealing plate, one end of the rectangular pipe is sleeved outside the protective covers, and the thickness of the nuts is smaller, the end face of the rectangular pipe is connected with the sealing plate in a linear friction welding mode, and the threaded rod section of the high-strength bolt is in threaded connection with the bolt platform.

In order to meet the requirement of node strength and save high-strength bolts, the number of the high-strength bolts is two.

In order to ensure that the pin can reliably lock the sleeve and the high-strength bolt, the pin hole in the sleeve is a threaded hole, the sleeve is in threaded connection with the pin, the pin hole in the prismatic section is a round hole, and the prismatic section is spliced with the pin.

The depth of the protective cover and the thickness of the sealing plate are smaller than the length of the high-strength bolt, and the depth of the high-strength protective cover and the thickness of the sealing plate and the length of the sleeve are larger than the length of the high-strength bolt. When the high-strength bolt is installed, the high-strength bolt cannot fall into the protective cover completely, and the sleeve can be adjusted to two sides to be respectively attached to the sealing plate and the bolt platform before the high-strength bolt is screwed into the bolt platform.

For convenience of manufacture, the protective cover is a metal square cover body with five surfaces.

The method for connecting the nodes of the aluminum alloy rectangular pipe reticulated shell based on linear friction welding is characterized by comprising the following steps: the method comprises the following steps:

(1) penetrating a high-strength bolt into the sealing plate, aligning the sleeve with pin holes on the prismatic section, then sleeving the sleeve into the high-strength bolt, screwing a pin into the pin holes of the sleeve and the high-strength bolt, and then screwing and fixing the sleeve, the high-strength bolt and the sealing plate by utilizing a nut matched with the high-strength bolt so that the sleeve, the high-strength bolt and the sealing plate cannot shake relatively;

(2) fixedly connecting a protective cover to the sealing plate, and covering a nut of the high-strength bolt in the protective cover;

(3) aligning the rectangular pipe to be welded with the sealing plate assembled in the step (1), applying a certain upsetting force to enable the rectangular pipe to be tightly contacted with the sealing plate, and then performing linear friction welding on the rectangular pipe and the sealing plate;

(4) after welding, cutting off outer burrs at the joint of the rectangular pipe and the sealing plate, screwing out the nut on the high-strength bolt, aligning the high-strength bolt with a corresponding threaded hole on the bolt platform, unscrewing the pin of the connecting sleeve and the high-strength bolt to enable the pin to be withdrawn from the high-strength bolt, driving the high-strength bolt to be screwed into the threaded hole of the bolt platform through the rotating sleeve until the sleeve is tightly jacked by the sealing plate and the bolt platform, and then screwing the pin of the connecting sleeve and the high-strength bolt again.

The invention has the beneficial effects that:

(1) by introducing the protective cover, the inner flash generated when the sealing plate and the rectangular pipe are subjected to friction welding does not affect the high-strength bolt, the protective cover has a limiting effect on the nut, when the high-strength bolt is screwed into the bolt table, a pin is not required to limit the high-strength bolt, and the high-strength bolt does not slide into the rectangular pipe, so that a chute is not required to be formed in the high-strength bolt, the strength of the high-strength bolt is improved, the structural strength of a node is high, the installation quality of the node is ensured, and the processing and manufacturing cost and time of the high-strength bolt are reduced; (2) rectangular pipe rod pieces are adopted, each rod piece of the joint only needs two high-strength bolts, and construction is convenient and rapid; the high-strength bolt and the sleeve rotate in a matching way by adopting the polygonal cross section, so that the false twisting phenomenon in the traditional net rack high-strength bolt is effectively avoided; (3) the rod piece and the sealing plate are connected by linear friction welding, and the strength of a welding seam and the strength of a base material are equal or basically equal; (4) the height of the section of the rod piece in the structure does not need to be uniform and can be adjusted according to the stress, and the section of the rod piece and the shearing resistance of the rod piece are not weakened at the node basically.

Drawings

FIG. 1 is an exploded view of a mesh shell node of an aluminum alloy rectangular tube of the present invention;

FIG. 2 is a schematic view of the assembled plate of the present invention with high strength bolts;

FIG. 3 is a schematic structural view of the sealing plate of the present invention in a state of being welded to a rectangular tube;

in the figure: 1-bolt platform, 2-closing plate, 3-protective cover, 4-high-strength bolt, 5-sleeve, 6-pin, 7-rectangular tube, 8-nut and 9-closing plate assembly.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

As shown in fig. 1, an aluminum alloy rectangular pipe reticulated shell joint based on linear friction welding comprises a rectangular pipe 7, a sealing plate 2 and a bolt platform 1, wherein the sealing plate 2 is connected with the bolt platform 1 through a high-strength bolt 4, the high-strength bolt 4 comprises a nut, a prism section and a threaded rod section which are sequentially connected into a whole, the rectangular pipe 7 and the sealing plate 2 are made of aluminum alloy, two high-strength bolts 4 are inserted into the sealing plate 2, the nuts of all the high-strength bolts 4 are positioned on the same side of the sealing plate 2, a sleeve 5 which is sleeved by the threaded rod section and matched with the prism section is arranged on the prism section of the high-strength bolt 4, the matching means that the two can be axially slidably sleeved, the sleeve can drive the prism section to rotate, the sleeve 5 is connected with the prism section through a pin 6, the sleeve 5 is in threaded connection with the pin 6, a hole for connecting the pin 6 on the prism section is a round hole, the pin 6 can be hung on the sleeve, the pin 6, after being screwed into the prismatic section, locks the sleeve 5 to the prismatic section, preventing both from moving axially. The nut is covered with a protective cover 3 fixed on the closing plate 2, and the protective cover is a metal square cover body with five surfaces. The pot head of rectangular pipe 7 is outside protection casing 3, and the thickness of nut is less than the degree of depth of protection casing 3 for the high strength bolt can remove the certain distance in protection casing 3, and two high strength bolts 4 of being convenient for screw in bolt platform 1 in proper order. The end face of the rectangular pipe 7 is connected with the sealing plate in a linear friction welding mode, and the threaded rod section of the high-strength bolt 4 is in threaded connection with the bolt platform 1.

The connecting method of the aluminum alloy rectangular pipe latticed shell joint based on linear friction welding comprises the following steps:

(1) the high-strength bolt 4 penetrates into the sealing plate 2, a round hole is formed in the sealing plate 2, so that the sealing plate 2 and the high-strength bolt 4 can rotate relatively, the sleeve 5 is sleeved into the high-strength bolt 4 after aligning the sleeve 5 with a pin hole in a prism section, the pin 6 is screwed into the sleeve 5 and the pin hole of the high-strength bolt 4, and then the sleeve 5, the high-strength bolt 4 and the sealing plate 2 are screwed and fixed by using the nut 8 matched with the high-strength bolt 4, so that the high-strength bolt cannot shake relatively; forming a closure plate assembly 9.

(2) Fixedly connecting a protective cover 3 to the sealing plate 2, and covering a nut of the high-strength bolt 4 in the protective cover 3;

(3) aligning the rectangular pipe to be welded with the sealing plate 2 of the sealing plate assembly 9 assembled in the step (1), applying a certain upsetting force P to enable the rectangular pipe 7 and the sealing plate 2 to be in tight contact as shown in fig. 3, and then performing linear friction welding on the rectangular pipe 7 and the sealing plate 2, wherein as shown by a bidirectional arrow on the rectangular pipe 7, the rectangular pipe 7 and the sealing plate 2 perform high-frequency reciprocating linear friction motion under the action of the upsetting force to generate a large amount of friction heat, so that metals on two sides of a contact surface are plastically deformed and are extruded out of an interface to form flash under the action of the friction force; when the deformation reaches a certain degree, the rectangular tube 7 stops vibrating rapidly, aligns with the sealing plate 2 and applies upsetting pressure, and metals on two sides of the interface are connected together through mutual diffusion and recrystallization, so that the whole linear welding process is completed; the welding method is a conventional linear friction welding method.

(4) After welding, the outer flash of the joint of the rectangular pipe 7 and the sealing plate 2 is cut off, then the nut on the high-strength bolt 4 is screwed out, the high-strength bolt 4 is aligned to the corresponding threaded hole on the bolt platform 1, the pin 6 of the connecting sleeve 5 and the high-strength bolt 4 is unscrewed, the pin 6 is made to withdraw from the high-strength bolt 4, the high-strength bolt 4 is driven to be screwed into the threaded hole of the bolt platform 1 through the rotating sleeve 5 until the sleeve 5 is tightly pressed by the sealing plate 2 and the bolt platform 1, and then the pin 6 of the connecting sleeve 5 and the high-strength bolt 4 is screwed again, so that the high-strength bolt 4 is prevented from being inversely screwed out of.

Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.

Claims

1. The utility model provides an aluminum alloy rectangular pipe reticulated shell node based on linear friction welding, includes rectangular pipe, shrouding and bolt platform, and the shrouding is connected its characterized in that through high strength bolt and bolt platform: the high-strength bolt comprises a nut, a prism section and a threaded rod section which are sequentially connected into a whole, the rectangular pipe and the sealing plate are made of aluminum alloy, the sealing plate is connected with at least two high-strength bolts in a rotating and inserting mode, the nuts of all the high-strength bolts are located on the same side of the sealing plate, sleeves which are sleeved with the threaded rod section and matched with the prism section are arranged on the prism section of the high-strength bolts, the sleeves are connected with the prism section through pins, the sleeves are in threaded connection with the pins, holes for connecting the pins on the prism section are round holes, a protective cover fixed on the sealing plate is covered outside the nuts, one end of the rectangular pipe is sleeved outside the protective cover, the thickness of the nuts is smaller than the depth of the protective cover, the end face of the rectangular pipe is connected with the sealing plate through linear friction welding, and.

2. The linear friction welding-based aluminum alloy rectangular tube reticulated shell joint of claim 1, wherein: the number of the high-strength bolts is two.

3. The linear friction welding-based aluminum alloy rectangular tube reticulated shell joint of claim 1, wherein: the pin hole on the sleeve is a threaded hole, the sleeve is in threaded connection with the pin, the pin hole on the prism section is a round hole, and the prism section is spliced with the pin.

4. The linear friction welding-based aluminum alloy rectangular tube reticulated shell joint of claim 1, wherein: the depth of the protective cover and the thickness of the sealing plate are smaller than the length of the high-strength bolt, and the depth of the high-strength protective cover and the thickness of the sealing plate and the length of the sleeve are larger than the length of the high-strength bolt.

5. The linear friction welding-based aluminum alloy rectangular tube reticulated shell joint according to any one of claims 1 to 4, wherein: the protective cover is a metal square cover body with five surfaces.

6. A method for connecting nodes of an aluminum alloy rectangular pipe reticulated shell based on linear friction welding according to any one of claims 1 to 4, characterized in that: the method comprises the following steps: