A method for finding a zero state of a curved surface structure

Abstract

The application discloses a curved surface structure zero state form finding method, comprising the following steps: (1) a model is established based on a design configuration, and deformation data is obtained by simulating the whole construction process; (2) a zero state configuration is deduced reversely: key node deformation values are extracted, arches are started, a simulation is re-performed after a linear model is fitted and adjusted, and iteration correction is performed until deformation error meets the requirement, and a zero state installation configuration is obtained; and (3) construction data is generated by extracting component line shapes and node coordinates. The application innovatively adopts an integral curvature adjustment strategy to replace a traditional node coordinate local adjustment mode, and through reverse deduction of 'construction simulation-control point arching-curved surface fitting-grid mapping', the problem of curved surface discontinuity caused by the traditional reverse superposition method is solved, construction precision and efficiency are significantly improved, and the application is suitable for intelligent construction of complex curved surface space grid structures.

Description

Technical Field

[0001] This invention relates to the field of building engineering technology, and more specifically to a zero-state form-finding method for curved surface structures. Background Technology

[0002] Complex curved spatial grid structures, with their superior aesthetic appeal and excellent mechanical properties, have become the preferred structural form for contemporary large-span buildings. However, in actual construction, traditional construction methods face two major technical bottlenecks:

[0003] (1) In terms of geometric control, although the simple nodal coordinate reverse displacement superposition adjustment method is easy to operate, it is difficult to maintain the overall geometric continuity of the surface. This local adjustment method often leads to discontinuities in the surface shape, which seriously affects the smoothness and mechanical properties of the structure;

[0004] (2) In terms of process control, existing methods mostly rely on the experience and judgment of construction personnel to make deformation adjustments, lacking a scientific and systematic iterative optimization mechanism. This extensive control method not only makes it difficult to guarantee construction accuracy, but also has low efficiency, which has become the main technical obstacle restricting the development of complex curved surface structures.

[0005] In existing technologies, pre-cambering of spatial steel structures can be achieved by directly adjusting the coordinates of nodes. However, this method, which directly pre-cambers each node to achieve pre-deformation, works well for spatial structures like trusses and space frames where overall alignment requirements are not high, but is not suitable for curved surface structures that require smooth overall alignment. Therefore, there is an urgent need for a form-finding method that can take into account the geometric characteristics of curved surfaces and achieve high-precision construction. Summary of the Invention

[0006] This invention provides a zero-state form-finding method for curved surface structures. Based on the theory of inverse deduction and iterative optimization, it adopts an overall curvature adjustment strategy to replace the traditional local adjustment method of node coordinates. Through the technical route of "construction simulation-control point arching-surface fitting-mesh mapping", it solves the problem of surface discontinuity caused by traditional local adjustment and realizes high-precision construction of complex curved surface structures.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: a zero-state form-finding method for curved surface structures, comprising the following steps:

[0008] (1) Simulation analysis of the entire construction process: Based on the design configuration, a structural model is established, and constraints and loads q are applied to simulate the entire construction process and obtain structural deformation data of the completed construction state;

[0009] (2) Reverse deduction of zero-state configuration:

[0010] Step (2.1): Extract the deformation values ​​of key nodes, and superimpose the deformation values ​​with opposite signs to obtain the key nodes after arching;

[0011] Step (2.2): Using the key nodes after arching as the reference, fit the line model after surface adjustment;

[0012] Step (2.3): Reconstruct the calculation model using the adjusted line model, apply the load q and simulate again to obtain new deformation data;

[0013] Step (2.4): Calculate the deformation error of the key nodes. If the error exceeds the threshold, repeat steps (2.1) to (2.4) for iterative updates until the convergence condition is met. The line model after surface adjustment that meets the convergence condition is the zero-state installation configuration of the surface mesh.

[0014] (3) Parameter extraction: Based on the final zero-state configuration, extract the zero-state alignment of the component and the zero-state installation coordinates of key nodes to generate component processing and construction guidance data.

[0015] Furthermore, the surface-adjusted line model in step (2.2) is obtained in the following way:

[0016] Step 1: Based on the coordinates of key nodes after arching, a quadratic distribution algorithm is used to fit the surface and generate a new surface geometric model that meets the overall curvature requirements;

[0017] Step 2: Using the orthogonal projection algorithm, map the remaining non-critical nodes onto the newly fitted surface to ensure that all nodes satisfy the geometric continuity condition;

[0018] Step 3: Based on the adjusted node coordinate set, reconstruct the structural line model to provide accurate geometric input for the next round of iterative analysis.

[0019] Furthermore, the convergence condition is that the deformation error of the key node is ≤1mm and the curvature deviation is ≤1°.

[0020] Furthermore, the key node is the point of maximum structural deformation or the geometric control point.

[0021] Furthermore, the surface fitting in step (2.2) is achieved using a parametric modeling tool.

[0022] Furthermore, deformation values ​​are monitored in real time during construction and compared with theoretical deformation to ensure that the forming position error is within the allowable range.

[0023] In summary, compared with traditional methods, the present invention has the following beneficial effects:

[0024] (1) The reverse deduction method of “construction simulation-control point arching-surface fitting-mesh mapping” is adopted. The zero-state configuration is optimized by iterative optimization, which has high computational efficiency and higher deformation simulation accuracy. The line shape after arching can be directly used for detailed design, processing and installation.

[0025] (2) For curved surface structures, the overall curvature adjustment is used instead of the node coordinate adjustment, which overcomes the problem of surface discontinuity caused by the traditional reverse superposition method and is suitable for geometric consistency control of complex curved surface mesh structures. Attached Figure Description

[0026] Figure 1 This is a flowchart of the zero-state installation process of the present invention;

[0027] Figure 2 This is a three-dimensional schematic diagram of an embodiment of the present invention;

[0028] Figure 3 A flowchart illustrating the process for determining the zero-state installation;

[0029] Figure 4 for Figure 3 Enlarged view of the middle section;

[0030] Figure 5 Comparison of the line model obtained by the zero-state installation method and the line model obtained by the traditional pre-arching method for the edge sealing beam 1;

[0031] Figure 6 This is a layout diagram of displacement monitoring points W1 and W2 during the construction process. Detailed Implementation

[0032] The following is in conjunction with the appendix Figures 1 to 6 The specific implementation of the zero-state shape finding method for curved surface structures of the present invention will be described in further detail.

[0033] This invention takes a single-piece three-dimensional curved surface grid for a roof as an example. Its structure is a single-layer suspended grid structure composed of triangular grid units. The overall structure is divided into 38 blocks by supporting columns and main load-bearing beams, forming a continuous wave-like shape under gravity. Combined with... Figure 1 The zero-state installation process, specifically focusing on a typical segment, introduces the detailed implementation of the zero-state shape-finding method. For example... Figure 2 As shown, the selected typical segment consists of edge-sealing beam 1 and internal grid beam 2. The structural characteristics are as follows: ① The line shape of the single beam in each direction has a high degree of geometric continuity; ② The grid segment as a whole exhibits multi-directional smooth curved surface characteristics; ③ The traditional nodal coordinate pre-camber method cannot meet the shape control requirements.

[0034] A zero-state form-finding method for curved surface structures is presented, with the specific steps as shown below. For ease of understanding, it is combined with... Figure 3 The determination process was demonstrated by selecting a curved beam from the surface of the embodiment:

[0035] Simulation analysis of the entire construction process: establishing a structural model based on the design configuration (i.e.) Figure 3After applying the corresponding constraints and loads q to the curved surface c), the following was obtained through simulation analysis of the entire construction process: ① The structural configuration after installation in the design state (i.e., Figure 3 medium curved surface c ’ ); ② Deformation data of each node.

[0036] Zero-state configuration inverse derivation:

[0037] Step (2.1): Extraction and inverse superposition of deformation at key nodes. Based on the construction simulation results, the key control nodes in the structure are first identified. In this embodiment, the node with the largest vertical deformation is selected as the key control point P0 (X0, Y0, Z0). Figure 3 As shown, the node P0 ( Figure 3 middle The vertical deformation value U0 of the marked point in the completed construction state is -110mm (upward is the positive direction). Based on the principle of reverse deduction, this deformation value U0 is superimposed onto node P0 with the opposite sign to obtain the critical node P0 after camber formation. ’ (X0, Y0, Z0+110);

[0038] Step (2.2): Using the critical node P0 after arching... ’ Based on this, a parametric tool is used to obtain the new surface after the first arching by fitting a quadratic distribution (i.e., Figure 3 The middle surface (a) is then used, and the orthogonal projection algorithm is employed to project the remaining nodes ( Figure 3 middle The identified points are mapped to the new surface, generating the first adjusted line model;

[0039] Step (2.3): Using the line model after the first surface adjustment, a calculation model is re-established, and predetermined constraints and design loads q are applied. The following is obtained again through simulation analysis of the entire construction process: ① The structural configuration after installation following the first pre-deformation (i.e., Figure 3 Mid-curved surface a ’ ); ② Deformation data of each node;

[0040] Step (2.4): Extract the deformation value of the key node again and calculate the deformation error; in this embodiment, the deformation value U1 of the key node extracted again is -107mm, and the deformation error with the pre-arch value U0 = -110mm is U1-U0=110-107=3mm. According to the convergence criterion of less than 1mm, the deformation error 3mm>1mm does not meet the convergence criterion. Figure 3 Specifically, this manifests as the structural configuration a after the first pre-deformation and installation. ’ It differs greatly from the design configuration c;

[0041] Step (2.5): Since the deformation error exceeds the allowable error, repeat steps (2.2) to (2.3) with a deformation value U1 = -107mm to continue adjusting the key node P0 in the reverse direction, and obtain the key node P0 after the second arching. ” and new surfaces (i.e.) Figure 3 (middle curved surface b), and then calculate the structural configuration after the second pre-deformation and installation (i.e. Figure 3 The deformation value U2 of the mid-curved surface (b') and key nodes is -107mm, and the deformation error U2-U1=107-107=0mm<1mm with the pre-camber value U1=-107mm satisfies the convergence requirement. Figure 3 Specifically, this manifests as the structural configuration b after installation following the second pre-deformation. ’ Similar to the design configuration c; the installation configuration obtained by adjusting the key nodes in the reverse direction with a deformation value U2 = -107mm (i.e. Figure 3 The curved surface (b) is the zero-state installation configuration of the curved surface mesh;

[0042] like Figure 5 This is a comparison diagram of the line model of the edge sealing beam 1 obtained by the zero-state installation method and the line model obtained by the traditional pre-camber method in this embodiment. Curve I is the design state line model, and the line model obtained by the traditional node pre-camber method is shown in Figure 1. Figure 5 The curve II is significantly better than the line model obtained using the zero-state installation method. Figure 5 The smoothness difference at the nodes of curve III (mid-curve) is such that the worst smoothness is located at the critical node ( Figure 5 middle (The marked points), the maximum curvature deviation reaches 4°, while the maximum curvature deviation of the line model obtained by the installation zero-state method is <1°. Therefore, the installation zero-state method of the present invention can better guarantee the geometric continuity requirements of the surface.

[0043] (3) Parameter extraction: Based on the final zero-state configuration, extract the zero-state alignment of the component and the zero-state installation coordinates of key nodes to generate processing and construction guidance data;

[0044] (4) Construction monitoring and verification: During construction, deformation values ​​are monitored in real time, and the theoretical deformation is compared with the actual deformation to ensure that the error between the formed shape and the design shape is less than the allowable value. For example Figure 6 As shown in the figure, displacement monitoring points W1 and W2 were arranged at key locations on the structure. The actual deformation value of monitoring point W1 was -104.3 mm, and the difference between the actual deformation value and the theoretical deformation value of -107 mm was only 2.7 mm; the actual deformation value of monitoring point W2 was -66.8 mm, and the difference between the actual deformation value and the theoretical deformation value of -69 mm was only 2.2 mm, both of which meet the accuracy requirements.

[0045] The above description is merely a preferred embodiment of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principles of the present invention should also be considered within the scope of protection of the present invention.

Claims

1. A zero-state shape-finding method for curved surface structures, characterized in that, Includes the following steps: (1) Simulation analysis of the entire construction process: Based on the design configuration, a structural model is established, and constraints and loads q are applied to simulate the entire construction process and obtain structural deformation data of the completed construction state; (2) Inverse deduction of zero-state configuration: Step (2.1): Extract the deformation values ​​of key nodes, and superimpose the deformation values ​​with opposite signs to obtain the key S nodes after arching; Step (2.2): Using the key nodes after arching as the reference, fit the line model after surface adjustment; Step (2.3): Reconstruct the calculation model using the adjusted line model, apply the load q and simulate again to obtain new deformation data; Step (2.4): Calculate the deformation error of the key nodes. If the error exceeds the threshold, repeat steps (2.1) to (2.4) for iterative updates until the convergence condition is met. The line model after surface adjustment that meets the convergence condition is the zero-state installation configuration of the surface mesh. (3) Parameter extraction: Based on the final zero-state configuration, extract the zero-state alignment of the component and the zero-state installation coordinates of key nodes to generate component processing and construction guidance data; The line model after surface adjustment in step (2.2) is obtained in the following way: Step 1: Based on the coordinates of key nodes after arching, a quadratic distribution algorithm is used to fit the surface and generate a new surface geometric model that meets the overall curvature requirements; Step 2: Using the orthogonal projection algorithm, map the remaining non-critical nodes onto the newly fitted surface to ensure that all nodes satisfy the geometric continuity condition; Step 3: Based on the adjusted node coordinate set, reconstruct the structural line model to provide accurate geometric input for the next round of iterative analysis.

2. The zero-state shape-finding method for curved surface structures according to claim 1, characterized in that: The convergence condition is that the deformation error of the key node is ≤1mm and the curvature deviation is ≤1°.

3. The zero-state form-finding method for curved surface structures according to claim 1, characterized in that: The key nodes are the points of maximum structural deformation or geometric control points.

4. The zero-state form-finding method for curved surface structures according to claim 1, characterized in that: The surface fitting in step (2.2) is achieved using a parametric modeling tool.

5. The zero-state shape-finding method for curved surface structures according to claim 1, characterized in that: Deformation values ​​are monitored in real time during construction and compared with theoretical deformation to ensure that the forming position error is within the allowable range.

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