An automatic design method for angle steel joints Wu Yuguang, Yang Bing (School of Mechanical and Electrical Engineering, Hohai University, Changzhou, Jiangsu). The shape of the point plate is cut and assembled according to the importance of the functional surface where the node is located to complete the node design.
72: A steel structure node refers to the intersection point of the rod connection. The rods participating in the connection are connected to each other through the node plate by welding or riveting. The main tasks of steel structure node design are: first determine the number of node plates at the node according to the function and structural requirements of the steel structure. The shape and orientation of each node plate, the positional relationship and connection relationship between the node plates, etc .; Under the force situation, the necessary strength calculation is performed according to certain rules and standards to determine the specific size of each node plate; finally, the construction drawing of the node plate is drawn according to the design results.
The design of steel structure joints is the most cumbersome and very important link in the entire design work. The workload of joint design accounts for about two-thirds of the total design workload. Especially in the construction drawings, the node graphics including related dimensions, annotations, etc. account for the vast majority of the drawings. Therefore, whether the joint design is proper will directly affect the design quality and engineering cost of the steel structure.
There are not many domestic and foreign technologies related to the design of connecting nodes of steel structural members. The current steel structure design software does not solve the node design problem well, and some steel structure software does not even have the node design function. The design of steel structure nodes basically uses template technology and parametric design ideas, such as the PDSoft system developed by the Chinese Academy of Sciences. Although this method has practical and reliable advantages, because of the large number of nodes and the large number, it is quite difficult to exhaust all the types of nodes, not to mention the establishment of all node libraries. Therefore, the degree of automation of node design is still very low.
This paper proposes an automatic design method for welded joint plates of angle steel structures. In this method, the steel structure node is regarded as the intersection of the surface where the connecting rod is located. First, the connected members at the node are divided according to the functional surface, and the shape and position of the node plate are automatically determined for each functional surface according to the type and orientation of the connected member, and then all the functional surfaces on the same node are corresponding The nodal plates are assembled, and the specific nodal plates are formed by mutual cutting of the nodal plates. This method does not need to establish a node model library.
1 The functional surfaces and basic joint plates of angle steel joints are the most general case of angle steel joints. The members on the angle steel joints are divided into three types of columns according to the spatial position relationship. As can be seen from the figure, according to their positional relationship with the nodes, the node plates that make up the angle steel nodes can be divided into fund projects: the Youth Science and Technology Fund Project of Hohai University Changzhou Campus (CJ2001-Journal of Hohai University Changzhou Branch There are three basic forms, as shown. The local coordinate system of the nodal plate is established according to the positional relationship between the connecting rods. It can be seen that these three nodal plates are used to connect the two phases of the rods in a quadrant. The rods in the adjacent quadrant and the rods in the four quadrants. These three types of nodal plates are called basic no.1, no.2 and no.3. These three kinds of basic nodal plates can form an arbitrarily complex angle steel node.
According to the three types of members on the joint, the surface formed by the axis of the members on the joint is divided into cylindrical surface, beam surface and bracing surface. Cylindrical surface means that the axis of the member that constitutes the plane can have columns, beams and braces, and it must contain the axis of the column angle steel plane; beam surface refers to the axis of the member that constitutes the plane only the beam and brace axis I'1 Line, and the plane in which the axis of the beam must be included; the bracing surface refers to the plane of the member axis that constitutes the plane of the basic joint plate of the angk, which has only the bracing axis, and there are no columns and beams on the joint. As shown, the line segment represents the member, and the intersection of the line segment represents the node. For example, Hachinohe 4, Hachinohe 3, P5P8, P6P7 are the axis of the column; however, P2P6, P5, P5P6, etc. are the axis of the beam; the cylindrical surface consists of a beam surface composed of PW2P5P6; and the node P9 has only bracing The surface is composed of P3P6 and P2P7.
2 Angle steel nodal plate automatic design algorithm The functional surface decomposition of the node 2.1 Determination of the basic nodal plate coordinate system From the above analysis, we can know that in order to determine which base plate type the nodal plate on a given functional surface belongs to, the first must be based on the plane The axis of the rod is used to establish a nodal plate coordinate system, and then the form of the basic nodal plate is determined according to the distribution of the rod axis in the coordinate system. The specific realization process of determining the nodal plate coordinate system is as follows: a. Taking the intersection of the axis of the bar as the origin of the nodal plate local coordinate system.
b. Determine the x axis of the nodal plate local coordinate system. If there is a case where the axis of the rod is penetrating to the origin of the local coordinate system, or if the axes of the two rods are collinear, then the axis of this type of rod is used as the x-axis. Otherwise, the x-axis is the rod with the largest difference between the remaining rods on both sides of the rod. The positive direction of the x-axis is determined according to the right-hand rule after the positive direction of the y-axis is determined.
For example, in (a), the axis of the rod a divides the axis of the remaining rods into two sides of a, and this division method can maximize the difference in the number of the remaining rods on both sides of a rod, so the rod a is the x-axis.
c. Determine the y-axis of the local coordinate system of the nodal plate. If there is only one bar perpendicular to the x-axis, and the bar penetrates to the origin of the local coordinate system ... then take the bar as the y-axis, and take the remaining bars on both sides of the x-axis with a large number! The side of the y-axis is Zheng Wuyuguang, waiting for an automatic design method of angle steel joints; if there is only one bar perpendicular to the x-axis, and the end point of the bar coincides with the origin of the coordinates, then the bar is taken as y The positive direction of the axis is the direction of the origin pointing to the other end of the rod, as shown in (b); otherwise, the side with the largest number of rods on both sides of the x-axis is the positive direction of the y-axis. If the rod a in (c) is the x-axis, the upward direction is the positive direction of the y-axis.
The nodal plate coordinate system determines the type of nodal plate selected for the plane according to the distribution of the axis of the rod in the local coordinate system. If the axis of the bar is distributed in one quadrant of the local coordinate system, the basic node plate No. i is selected; the basic node plate No. 2 is distributed in the two adjacent quadrants of the local coordinate system; otherwise, the basic node plate No. 3 is selected. For example, the nodes shown in (b) and (c) use No. 2 node plate, and (a) use No. 3 node plate.
2.2 Automatic Generation Algorithm of Angle Steel Nodal Plates In the automatic generation algorithm of angle steel nodal plates, the given angle steel nodes are first divided into various functional surfaces, a coordinate system is established for each functional surface, and the type of the nodal plate is determined according to this coordinate system . Specify a uniform length and width for nodal plates of the same type. Since the nodal plates on different functional surfaces on the nodes interfere with each other, it is determined which nodal plate should subtract the phase interference part according to the importance of the nodal plates. The algorithm block diagram is shown below. The realization process is to traverse the angle steel nodes of the steel structure, and process each node as follows: Journal of Hohai University Changzhou a. Determine the type of node plate on all cylinder surfaces. When there are multiple cylinders at a node, the processing order of each cylinder is as follows: first determine the cylinder with beams passing through the current node, then determine the cylinder with two beams coplanar, and third determine the cylinder with only one beam , And finally determined that there is no beam but only the cylindrical surface of the brace. For the nodal plates on each cylinder surface, use all determined nodal plates to intersect with it geometrically, minus the intersection, and the remaining part is the actual shape and position of the current nodal plate.
b. Determine the gusset on the beam surface. Use all the determined gussets to intersect it geometrically, minus the intersection, and the remaining part is the actual shape and position of the current gusset.
c. Determine the joint plate on the supporting surface. For a space node with multiple braces, the processing sequence is: first determine the brace that has braces through the node, and then determine the brace that has two brace axes coplanar.
After the above algorithm, the shape of the nodal plate at each node can be determined. Then use the geometric parameter extraction module of the nodal plate to determine the geometric parameters of each nodal plate, determine the specific size of the nodal plate on the node through strength calculation or interactive design, and complete the nodal design.
3 Example Introduction The automatic generation algorithm of angle steel node plates has been used in the angle steel node design module of the light steel structure automatic design software system that the author is studying. In order to realize the automatic design of light steel structure, the system established a computer representation model of the steel structure. This model is in Tian Jingcheng, Liu Xiaoping, Tang Weiqing, etc. Automatic labeling algorithm of node graph in structure. Journal of Computer Aided Design and Graphics, 1999, 11 Liu Xiaoping, Tao Xiaoyun, Hu Xuegang, etc. Engineering design system function and frame analysis research (Part 1)-Overview of domestic and foreign architectural steel structure and node design software. Anhui Architecture, 2000 (6): 111-112. Tian Jingcheng, Hu Songlin, Liu Xiaoping, etc. Research and application of template technology in the design of steel structure joints. Li Hehua, Computer Aided Design and Graphics. Design manual for steel connection nodes. Beijing: China Building Industry Press, 1999 Wu Yuguang, Guo Jun. An intelligent design method for welding frame. Journal of Computer Aided Design and Graphics, 2001, 13 (
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