CN112302159A - Novel assembled cast steel node of grid structure - Google Patents
Novel assembled cast steel node of grid structure Download PDFInfo
- Publication number
- CN112302159A CN112302159A CN202010828881.1A CN202010828881A CN112302159A CN 112302159 A CN112302159 A CN 112302159A CN 202010828881 A CN202010828881 A CN 202010828881A CN 112302159 A CN112302159 A CN 112302159A
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- Prior art keywords
- steel ball
- cast steel
- node
- ball
- branch pipes
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Classifications
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- E—FIXED CONSTRUCTIONS
- E04—BUILDING
- E04B—GENERAL BUILDING CONSTRUCTIONS; WALLS, e.g. PARTITIONS; ROOFS; FLOORS; CEILINGS; INSULATION OR OTHER PROTECTION OF BUILDINGS
- E04B1/00—Constructions in general; Structures which are not restricted either to walls, e.g. partitions, or floors or ceilings or roofs
- E04B1/18—Structures comprising elongated load-supporting parts, e.g. columns, girders, skeletons
- E04B1/19—Three-dimensional framework structures
- E04B1/1903—Connecting nodes specially adapted therefor
- E04B1/1906—Connecting nodes specially adapted therefor with central spherical, semispherical or polyhedral connecting element
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- E—FIXED CONSTRUCTIONS
- E04—BUILDING
- E04B—GENERAL BUILDING CONSTRUCTIONS; WALLS, e.g. PARTITIONS; ROOFS; FLOORS; CEILINGS; INSULATION OR OTHER PROTECTION OF BUILDINGS
- E04B1/00—Constructions in general; Structures which are not restricted either to walls, e.g. partitions, or floors or ceilings or roofs
- E04B1/18—Structures comprising elongated load-supporting parts, e.g. columns, girders, skeletons
- E04B1/19—Three-dimensional framework structures
- E04B1/1903—Connecting nodes specially adapted therefor
- E04B2001/1921—Connecting nodes specially adapted therefor with connecting nodes having radial connecting stubs
Abstract
The invention relates to a novel assembled cast steel node, and belongs to the field of space grid structure node innovation. The novel assembled cast steel ball joint is internally provided with a cavity, an external branch pipe is connected with a steel ball into a whole, the connection between the branch pipe and the steel ball is smooth in structure through a fillet, the branch pipe is distributed along the circumferential direction of the steel ball, four steel pipes of an upper hemisphere extend outwards in an inclined mode, four steel pipes of a middle hemisphere extend outwards in an axial direction, the middle of a connecting part between the steel pipes and the steel ball is hollow, an inclined rod piece inside the ball is obtained through topological optimization, and the inclined rod piece and an external ball shell are integrated. The surface of the steel ball is provided with a curved surface shape which is obtained by topological optimization calculation and is matched with the stress of the bearing steel rod by taking the number of branch pipes, the position of the branch pipes and the diameter of the branch pipes as parameters. And the topological optimization analysis is carried out on the ball nodes, so that the self weight of the assembled cast steel ball nodes is greatly reduced while various mechanical properties are met.
Description
Technical Field
The invention belongs to the field of space grid structure node innovation, and particularly relates to a novel assembly type cast steel node of a grid structure, which is mainly applied to structures of grids and grid floors of airport terminal buildings, high-speed railway stations, large-scale gymnasiums and the like.
Background
At present, the grid structure is widely applied to airport terminal buildings, high-speed rail stations, world expo-stadiums, large-scale stadiums and the like due to the fact that the grid structure is reasonable in stress, light in self weight and low in manufacturing cost. The nodes, which are members connecting the bars of the lattice structure, can often weigh 20% to 50% of the total steel used in the structure. Therefore, reasonable nodes can greatly reduce the construction cost and improve the safety.
The grid structure is commonly provided with a welded ball joint, a bolt ball joint and a cast steel ball joint, and along with the continuous improvement of people on building requirements, the assembled structure is generally applied by the advantages of diversified design, fast construction progress, energy conservation, environmental protection and the like. Compared with a welded ball joint, the cast steel ball joint has the advantages that the residual stress is smaller, the construction is convenient, the workload of high-altitude operation is greatly reduced, the construction cost is reduced, the overall engineering quality is improved, and meanwhile, the harm to constructors caused by the high-altitude operation is also greatly reduced. Therefore, cast steel ball joints are most commonly used in fabricated buildings. The traditional cast steel ball joint is generally prefabricated by a factory and then transported to a construction site for on-site welding, the construction progress is slow, the ball joint is generally a hollow ball, and the conventional cast steel hollow ball joint has the defect that the force transmission path of the structure cannot be completely reflected, so that a lot of materials cannot be completely stressed, and the joint occupies a large amount of proportion in the structure.
Therefore, it is necessary to manufacture a novel cast steel ball joint and is also urgently needed in the engineering at the present stage. The key technology for realizing the manufacture of the novel cast steel node has three points, and firstly, the lightweight design target needs to be met, which is also the key point of the design; secondly, the shape is beautiful, the novel node is generally applied to a symbolic building, and the novel node is not only used for reducing the manufacturing cost, but also needs to make people feel beautiful; thirdly, how to manufacture the novel node, the traditional machine tool is difficult to meet the manufacturing requirement, and a new method is needed to solve the manufacturing problem.
Disclosure of Invention
Compared with the original cast steel ball node, the invention is a new node form, and designs a new node for the solid ball node through topology optimization research on the basis of meeting various mechanical properties, thereby reducing the construction cost on the basis of meeting the aim of light weight.
The invention adopts the following technical scheme: a novel cast steel node is characterized in that a steel ball is connected with 9 branch pipes which extend outwards, the branch pipes are hollow pipes, and the connection parts of the branch pipes and the steel ball are communicated, so that the novel cast steel node has high integrity.
The branch pipes are 8 secondary pipes, 1 main pipe extends out of the lower hemispherical area, 4 secondary pipes extend out of the spherical central area, 4 secondary pipes extend out of the upper hemispherical area in an inclined mode, and the radius of each secondary pipe is smaller than that of each main pipe.
Bolt holes are reserved at outer end parts of branch pipes
The steel ball is internally of a hollow structure, the curve is smooth, and the form of the steel ball meets the reasonable form obtained by topological optimization calculation.
4 oblique supports are arranged inside the steel ball, are all solid, are integrated with the inner ball wall, and extend from the midspan inner spherical surface to the central area of the four secondary tubes above along the oblique direction, so that the support meets the path of force transmission.
The steel ball is not a perfect circle structure, and has obvious curve.
According to the particularity of the model, a model making method is provided
(1) According to the diameter of the steel ball and the diameter of the branch pipe, the diameter of a reserved bolt hole is taken as a parameter, and a three-dimensional structure of a novel cast steel ball node is designed by utilizing a topological optimization method;
(2) designing a three-dimensional model of a novel cast steel ball node according to a topological optimization result, and respectively casting a foam three-dimensional model and a sand mold three-dimensional model according to the three-dimensional model;
(3) making a solid foam model according to the foam three-dimensional model;
(4) performing wood molding core modeling according to the sand mold three-dimensional model;
(5) coating alcohol-based paint with the thickness of more than 2 mm on a foam pattern without a cavity, and filling organic ester water glass sand with a certain ratio to start molding;
(6) after the sand mold is vibrated to be compact and hardened completely, taking out the foam in the sand mold in a destructive mode to form a cavity;
(7) putting a sand core made of a wood pattern into the steel ball cavity, and performing mould assembling and pouring after brushing the alcohol-based coating on the surface of the wood pattern;
(8) after the casting after the box opening is subjected to the working procedures of heat treatment, chemical component detection, flaw detection, size measurement and the like, the casting is qualified and can be put into use.
The invention has the following beneficial effects: the novel assembled cast steel ball node is a hollow ball node, the dead weight of the node is greatly reduced, materials are saved, the construction difficulty is effectively reduced, the shape and the structure of a steel ball are obtained through topological optimization design, the structure of the whole cast steel ball node is improved, the cast steel ball node is concise and attractive in form, convenient to connect and high in installation precision, the use performance of the cast steel ball node is optimized, the force transmission route of the cast steel ball node is clear, the stress form is reasonable, and the safety and stability are high.
The counter bores are bolt holes, bolts are arranged at the end parts of the steel rods to be connected, and the bolts at the end parts of the steel rods are fixedly connected with the bolt holes in the branch pipes, so that the steel rods are fixedly connected with the cast steel ball nodes. The invention mainly utilizes the principle of topological optimization to carry out optimization analysis on the cast steel ball to obtain a novel cast steel ball node, and the dead weight of the steel ball can be greatly reduced on the basis of meeting the bearing performance of the node. The steel ball casting node is cast by adopting a lost foam-sand core type composite casting process suitable for producing complex special-shaped castings, the composite process not only utilizes the advantages of high degree of freedom of lost foam pattern design, easiness in foam processing and low price, avoids the problems of deformation and recarburization, but also retains the advantages of stable mold filling and stable casting component and size in sand casting.
Description of the drawings:
FIG. 1 is a front view of an assembled node of the present invention;
FIG. 2 is an axial cut-away view of the fabricated node of the present invention;
FIG. 3 is a top view of the fabricated node of the present invention;
FIG. 4 is a bottom view of the fabricated node of the present invention;
in the drawings
1. A middle shaft extending outwards;
2. an upper shaft extension tube;
3. a bolt hole is reserved at the outer end of the secondary pipe;
4. the inner part of the ball and the inner ball wall are integrally supported;
5. a ball inner cavity;
6. a chamfer is arranged in the connecting area of the steel ball and the outer extension pipe;
7. a bolt hole is reserved at the outer end of the main pipe;
8. novel assembled node main part.
9. Main pipe
The specific implementation mode is as follows:
in order to make the technical purpose, technical means and advantages of the present invention more clear, the following description of the embodiments of the present invention with reference to the accompanying drawings.
As shown in fig. 1-4, the middle steel ball has 9 outer tubes, the upper part extends 4 secondary tubes obliquely, the middle part extends 4 secondary tubes horizontally, the lower part has an outer main tube, the ball body is integrated with the outer tubes, the outer radius of the outer secondary tube is 60mm, the inner radius of the outer secondary tube is 40mm, the outer radius of the outer main tube is 80mm, and the inner radius of the outer main tube is 60 mm. The inner part of the outer extension pipe and the ball are connected is hollow.
Fig. 1 is a front view of a fabricated node of the present invention, fig. 2 is an axial sectional view of the fabricated node of the present invention, fig. 3 is a top view of the fabricated node of the present invention, and fig. 4 is a bottom view of the fabricated node of the present invention.
The secondary pipe 1 extends outwards along the ball shaft and is uniformly distributed along the circumferential direction, the extending length of the secondary pipe extends out of the ball body by 90mm and is integrated with the ball body, and the chamfer angle 6 is a 60-degree chamfer angle. The secondary pipes 2 are uniformly distributed along the slant direction, the number of the secondary pipes is 4, the extending length of the secondary pipes is 90mm, and the connection mode of the secondary pipes is the same as that of the secondary pipes 1.
The steel ball 8, the branch pipe 1, the branch pipe 2 and the main pipe 9 are integrally formed, and chamfers are arranged among the steel ball, the branch pipe and the main pipe to ensure that the outer extension pipe and the cast steel node are in smooth transition. Avoids the stress concentration phenomenon in the transition region of the traditional node and improves the bearing capacity
The outer ends of the secondary pipe 1 and the secondary pipe 2 are provided with reserved bolt holes, so that the assembled connection can be conveniently installed on an installation site.
The ball inner oblique integrated support obliquely upwards extends from the middle of two adjacent middle axis secondary tubes, the interval between the starting point and the beam adjacent tube is 45 degrees, the top of the oblique support is arranged at the central part of the upper axis outer extension tube, the oblique support and the ball inner cavity are integrally formed, and a smooth-transition curved surface chamfer angle is arranged between the steel ball inner cavity and the oblique support.
Specifically, in order to compare the difference between the novel assembled cast steel node designed by topology optimization and the traditional node, the mechanical properties of the novel assembled cast steel node are analyzed and compared by using large-scale analysis software Ansys, and the mechanical properties can be obtained by comparing the following table under the condition of controlling the same load:
| type (B) | Node quality (t) | Maximum displacement (mm) | Mises stress (Mpa) |
| Novel assembled cast steel node | 94.9 | 0.109 | 176.0 |
| Traditional cast steel ball joint | 97.7 | 0.186 | 312.3 |
Compared with the two types of nodes in the table, compared with the novel assembled cast steel node, the traditional hollow cast steel ball node has the advantages that the maximum displacement is increased by 70.64% and the maximum Mises stress is increased by 77.44% under the condition that the mass is increased by 2.95%.
The result shows that the load resisting capacity of the novel assembled cast steel node is far better than that of the traditional cast steel ball node, and the maximum displacement of the novel assembled cast steel node is far smaller than that of the traditional cast steel ball node when the novel assembled cast steel node is subjected to the same load. The embodiment shows that the novel assembled cast steel ball joint is feasible and has good application value.
The bolt ball node is cast by adopting a lost foam-sand core composite casting process suitable for producing complex special-shaped castings, the composite process not only utilizes the advantages of high degree of freedom of lost foam pattern design, easiness in foam processing and low price, avoids the problems of deformation and recarburization, but also retains the advantages of stable sand casting mold filling and stable casting component and size.
The casting is carried out by adopting a lost foam-sand mold composite casting process, which comprises the following steps:
(1) according to the diameter of the steel ball and the diameter of the branch pipe, the diameter of a reserved bolt hole is taken as a parameter, and a three-dimensional structure of a novel cast steel ball node is designed by utilizing a topological optimization method;
(2) designing a three-dimensional model of a novel cast steel ball node according to a topological optimization result, and respectively casting a foam three-dimensional model and a sand mould three-dimensional model by adopting a 3D printing technology according to the three-dimensional model;
(3) making a solid foam model according to the foam three-dimensional model;
(4) performing wood molding core modeling according to the sand mold three-dimensional model;
(5) coating alcohol-based paint with the thickness of more than 2 mm on a foam pattern without a cavity, and filling organic ester water glass sand with a certain ratio to start molding;
(6) after the sand mold is vibrated to be compact and hardened completely, taking out the foam in the sand mold in a destructive mode to form a cavity;
(7) putting a sand core made of a wood pattern into the steel ball cavity, and performing mould assembling and pouring after brushing the alcohol-based coating on the surface of the wood pattern;
(8) after the casting after the box opening is subjected to the working procedures of heat treatment, chemical component detection, flaw detection, size measurement and the like, the casting is qualified and can be put into use.
Because the node shape is complicated, in order to avoid the foam from deforming in the molding process and influencing the dimensional accuracy of the casting, the external contour of the node is only manufactured by using a lost foam, and the hollow cavity and the threaded hole are additionally formed by using a wood molding sand core. Compared with other sand molds, the sodium silicate sand has the advantages of low cost, easy operation, better deformability than resin sand, no harmful elements, convenient hardening process due to the adoption of organic vinegar, less pores and cracks in castings, smooth surface and improved dimensional precision. After the casting after unpacking is subjected to the working procedures of heat treatment, chemical component detection, flaw detection, size measurement and the like, the bolt counter bore is finely machined on a lathe, and the qualified bolt counter bore can be delivered to the engineering for use
The invention has the following beneficial effects:
1. the novel assembled cast steel ball joint is a hollow ball joint, so that the dead weight of the joint is greatly reduced, and materials are saved.
2. The construction difficulty is effectively reduced, the outer extension pipe is reserved with the bolt holes, so that the cast steel ball joint is simple and attractive in form, convenient to connect and high in installation precision.
3. The shape and the structure of the steel ball are obtained through topological optimization design, so that the structure of the whole cast steel ball node is improved, the service performance of the cast steel ball node is optimized, the force transmission route of the cast steel ball node is clear, the stress form is reasonable, and the safety and the stability are high.
4. Effectively reducing the stress concentration phenomenon and the problem of overlarge quality of the traditional cast steel ball joint.
5. The assembled cast steel ball joint is cast by combining the traditional lost foam-sand core composite casting process, so that the design freedom is high, the cost is greatly reduced, the surface of the steel ball joint is smooth, the precision is high, and the assembled cast steel ball joint is suitable for industrial production.
While the present invention has been described in detail and with reference to the embodiments thereof as illustrated in the accompanying drawings, it will be apparent to one skilled in the art that various changes can be made therein. Therefore, certain details of the embodiments are not to be interpreted as limiting, and the invention is to be defined by the scope of the appended claims.
Claims (6)
1. The utility model provides a novel assembled cast steel ball node which characterized in that includes: the oblique support in the cavity of the cast steel ball is obliquely upward from the middle of two adjacent middle secondary axial tubes, the interval between the starting point and the adjacent tube of the beam is 45 degrees, the top of the oblique support is arranged at the central part of the outer extension tube of the upper shaft, the oblique support and the inner cavity of the ball are integrally formed, and the inner cavity of the steel ball and the oblique support are a unified whole obtained through optimization.
2. The surface of the steel ball is provided with a curved surface shape which is obtained by topological optimization calculation and is matched with the stress of the bearing steel rod, wherein the curved surface shape is obtained by taking the number of branch pipes, the position of the branch pipes, the diameter of the branch pipes and the diameter of the counter bore as parameters.
3. The novel bolt ball joint according to the claim 1 and 2, characterized in that the branch pipes comprise a plurality of groups of branch pipes, the distribution of the plurality of groups of branch pipes is that each group of branch pipes are uniformly distributed along the circumferential direction of the steel ball and the included angle between the branch pipes and the axis of the steel ball.
4. The novel fabricated cast steel node according to the claim 1, the claim 2 or the claim 3, wherein the bottom of the branch pipe is communicated with the cavity structure.
5. The novel assembled cast steel ball joint as claimed in claim 4, wherein bolt holes are reserved on the outer portion of the outer extension pipe.
6. The novel assembled cast steel ball joint as claimed in claim 5, wherein the joint of the branch pipe and the steel ball is smoothly transited in a fillet manner.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010828881.1A CN112302159A (en) | 2020-08-18 | 2020-08-18 | Novel assembled cast steel node of grid structure |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010828881.1A CN112302159A (en) | 2020-08-18 | 2020-08-18 | Novel assembled cast steel node of grid structure |
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| Publication Number | Publication Date |
|---|---|
| CN112302159A true CN112302159A (en) | 2021-02-02 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202010828881.1A Pending CN112302159A (en) | 2020-08-18 | 2020-08-18 | Novel assembled cast steel node of grid structure |
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Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE2615796A1 (en) * | 1976-04-10 | 1977-10-27 | Josef Serwe | Framework tie rod connection system - uses bolts retained inside rods by expanders for connection to cage using locknuts |
| CN201305928Y (en) * | 2008-11-27 | 2009-09-09 | 浙江省电力设计院 | Extra-large welded hollow spherical joint |
| CN201679093U (en) * | 2010-04-06 | 2010-12-22 | 温州泰昌铁塔制造有限公司 | Steel ball joint of power transmission tower |
| CN107829494A (en) * | 2017-11-24 | 2018-03-23 | 河南大学 | A kind of Novel bolt ball node and preparation method thereof |
| CN110318461A (en) * | 2019-06-24 | 2019-10-11 | 太原理工大学 | Round steel pipe supports connection bolt cydariform spherical housing node |
-
2020
- 2020-08-18 CN CN202010828881.1A patent/CN112302159A/en active Pending
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE2615796A1 (en) * | 1976-04-10 | 1977-10-27 | Josef Serwe | Framework tie rod connection system - uses bolts retained inside rods by expanders for connection to cage using locknuts |
| CN201305928Y (en) * | 2008-11-27 | 2009-09-09 | 浙江省电力设计院 | Extra-large welded hollow spherical joint |
| CN201679093U (en) * | 2010-04-06 | 2010-12-22 | 温州泰昌铁塔制造有限公司 | Steel ball joint of power transmission tower |
| CN107829494A (en) * | 2017-11-24 | 2018-03-23 | 河南大学 | A kind of Novel bolt ball node and preparation method thereof |
| CN110318461A (en) * | 2019-06-24 | 2019-10-11 | 太原理工大学 | Round steel pipe supports connection bolt cydariform spherical housing node |
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Application publication date: 20210202 |