Virtual-reality fusion system and method for ultimate strength test of hull structure

Abstract

The present invention relates to a virtual-reality fusion system and method for the ultimate strength test of a hull structure. It includes a high-fidelity virtual modeling module and a virtual assembly module. Based on the three-dimensional model of the virtual physical test scene and the three-dimensional model of the ultimate strength virtual physical test constructed in the high-fidelity virtual modeling module, a virtual physical test system for the ultimate strength of the hull structure is constructed; a virtual-reality data fusion module is used to virtual-reality fuse the ultimate strength real physical test information of the hull structure and / or the ultimate strength simulation calculation information of the hull structure on the above-built ultimate strength virtual physical test system of the hull structure; a virtual decision and prediction module is used to perform the required display on the above-built ultimate strength virtual physical test system of the hull structure and / or the ultimate strength virtual physical test system of the hull structure after the response field is reconstructed. The present invention can effectively realize the data fusion of the ultimate strength of the hull structure and improve the degree of refinement of the ultimate strength test of the hull structure.

Description

Technical Field

[0001] The present invention relates to a virtual-real fusion system and method, in particular to a virtual-real fusion system and method for ultimate strength testing of a hull structure. Background Art

[0002] Hull structure ultimate strength testing is an essential step in the shipbuilding process, playing a crucial role in evaluating and assessing the safety and stability of hull structures. As future ships develop towards deep-sea, green, polar, and intelligent capabilities, the shortcomings of existing hull structure ultimate strength physical testing are becoming increasingly apparent.

[0003] Traditional physical tests of the ultimate strength of hull structures are easily restricted by various factors such as site, equipment, and cost. They have problems such as long cycles, limited verification content, low test repeatability, and scattered information throughout the test process. At the same time, the test process has a low level of visualization, which affects the real-time decision-making of test personnel and the test is not refined enough.

[0004] With the rapid development of new-generation information technology, the use of three-dimensional virtual system modeling and simulation for the ultimate strength test of hull structures is becoming increasingly common. However, in the process of virtual modeling and simulation in the three-dimensional virtual model system, in order to improve the refinement of the test, it is necessary to fuse the physical test data in the traditional physical test of the ultimate strength of hull structures with the three-dimensional virtual modeling and simulation, that is, there is a need for virtual-real fusion.

[0005] In the ultimate strength test of hull structure, due to the differences between the three-dimensional virtual model system and the traditional physical test of the ultimate strength of hull structure, there are many technical difficulties in the integration of virtual and real, which makes it difficult to meet the current needs of the ultimate strength test of hull structure. Summary of the Invention

[0006] The purpose of the present invention is to overcome the deficiencies in the prior art and provide a virtual-reality fusion system and method for the ultimate strength test of hull structure, which can effectively realize the data fusion of the ultimate strength of hull structure and improve the degree of refinement of the ultimate strength test of hull structure.

[0007] According to the technical solution provided by the present invention, the virtual-reality fusion system for hull structure ultimate strength test includes:

[0008] A high-fidelity virtual modeling module is used to construct a three-dimensional virtual model for the ultimate strength test of the hull structure, wherein the constructed three-dimensional virtual model includes at least a three-dimensional model of a virtual physical test scene for constructing a virtual physical test scene and a three-dimensional model of an ultimate strength virtual physical test for constructing an ultimate strength virtual physical test of the hull structure;

[0009] A virtual assembly module, which builds a virtual physical test system for the ultimate strength of a hull structure based on the three-dimensional model of the virtual physical test scene and the three-dimensional model of the ultimate strength virtual physical test constructed in the high-fidelity virtual modeling module. The constructed virtual physical test system for the ultimate strength of a hull structure includes a virtual physical test scene and an ultimate strength virtual physical test platform system based on the virtual physical test scene.

[0010] A virtual-real data fusion module is used to fuse the real physical test information of the hull structure ultimate strength and / or the ultimate strength simulation calculation information of the hull structure on the above-mentioned hull structure ultimate strength virtual physical test system to achieve the response field reconstruction of the hull structure ultimate strength test;

[0011] The virtual decision-making and prediction module is used to display the above-mentioned hull structure ultimate strength virtual physical test system and / or the hull structure ultimate strength virtual physical test system after the response field is reconstructed.

[0012] The high-fidelity virtual modeling module includes a virtual structural test platform, a virtual loading system, a virtual test fixture and a virtual sensor unit; wherein,

[0013] A virtual structural test platform is used to build a virtual physical test scene. The three-dimensional model of the virtual physical test scene in the virtual structural test platform includes a structural test platform model, a test plant model, a hydraulic pump source model, a cooling system model, and a driving model;

[0014] The virtual loading system includes load loading equipment models of the 1000kN-30MN series;

[0015] The virtual test fixture includes a reaction frame model, a beam model, a tie rod model and an anchor bolt model;

[0016] The virtual sensor unit includes a displacement sensor model, a force sensor model, a strain sensor model and / or an image sensor model.

[0017] When the virtual-real data fusion module is used to perform virtual-real fusion on the hull structure ultimate strength virtual physical test system, the virtual-real fusion includes reconstructing measured strain information in a real physical test of the ultimate strength of a hull structure on the hull structure ultimate strength virtual physical test system, wherein the virtual-real fusion method includes:

[0018] For the hull structure, determining the strain sampling point distribution of the hull structure in a real physical test of the ultimate strength, and establishing a theoretical strain-displacement correspondence relationship of the hull structure;

[0019] Based on the theoretical strain-displacement correspondence established above, in the actual physical test of the ultimate strength of the hull structure, the unit measured strain information sampled at each strain sampling point is used to determine the theoretical sampling point displacement and sampling point stress of the current strain sampling point based on the unit measured strain information;

[0020] Generate a structural response field of the hull structure during a real physical test of ultimate strength based on the measured strain information of all strain sampling points, the theoretical sampling point displacements and sampling point stresses corresponding to all strain sampling points, wherein the structural response field includes strain, displacement and stress fields;

[0021] For the virtual physical test system of the ultimate strength of the hull structure, the required structural response field is reconstructed in real time based on the structural response field obtained above, so as to load the real-time displacement stress field information in the real physical test of the ultimate strength of the hull structure on the virtual physical test system of the ultimate strength of the hull structure.

[0022] For the hull structure, a four-node inverse shell finite element of the hull structure based on the NURBS basis function is constructed, and a theoretical strain-displacement correspondence relationship of the hull structure is established based on the constructed four-node inverse shell finite element. The established theoretical strain-displacement correspondence relationship of the hull structure is:

[0023]

[0024] Where u is the theoretical displacement, n is the number of strain sampling points on the hull structure, and ε i is the unit theoretical strain information of the i-th strain sampling point, N i (ξ) is the NURBS basis function of the i-th strain sampling point, and ξ is the parameter coordinate of the hull structure at the strain sampling point.

[0025] When generating the structural response field of the hull structure during the ultimate strength real physical test, it includes the linear structural response field with constant stiffness and the nonlinear structural response field with varying stiffness, among which,

[0026] When generating a linear structural response field, this includes:

[0027] For any strain sampling point, construct the least square error function between the measured strain information of the unit and the theoretical strain information of the unit at the strain sampling point;

[0028] Taking a minimum value of the constructed least squares error function based on the least squares error function to determine a sampling point displacement unit matrix of the current strain sampling point;

[0029] Assemble the sampling point displacement element matrices of all strain sampling points to form the overall matrix of the hull structure;

[0030] The overall matrix of the hull structure is analyzed to generate a linear structural response field, where the generated linear structural response field includes the hull strain, hull stress, and displacement of the hull under the current ultimate strength physical test state.

[0031] When generating nonlinear structural response fields, this includes:

[0032] Determine the nonlinear loading section of the hull structure in the real physical test of ultimate strength;

[0033] Under each load segment, the overall matrix of the hull structure under each load segment is determined by generating a linear structural response field;

[0034] The overall matrix of the hull structure is analyzed to generate a nonlinear structural response field under the current load segment. The generated nonlinear structural response field includes the hull strain, hull stress and displacement of the hull under the current ultimate strength physical test state.

[0035] When the virtual-real data fusion module is used for virtual-real fusion on the hull structure ultimate strength virtual physical test system, the virtual-real fusion includes real-time matching of virtual-real fusion, wherein:

[0036] The real-time matching virtual-real fusion at least fuses the simulation test results of the finite element calculation of the ultimate strength of the hull structure with the real test data of the real physical test of the ultimate strength of the hull structure on the hull structure ultimate strength virtual physical test system;

[0037] The real-time matching of virtual-reality fusion includes real-time comparison of the simulated load-displacement curve of the ultimate strength finite element calculation and the measured load-displacement curve of the ultimate strength real physical test, as well as real-time matching of the measured load based on the ultimate strength real physical test and the ultimate strength finite element calculation results on the ultimate strength virtual physical test system of the hull structure.

[0038] The real-time matching and fusion of the measured loads based on the ultimate strength real physical test and the simulated loads based on the ultimate strength finite element calculation include:

[0039] For any measured load F, the load data F′ is traversed frame by frame in the ultimate strength simulation test results. Based on the principle of minimizing FF′, all numerical simulation result data in the corresponding frame are extracted to be reconstructed and displayed on the hull structure ultimate strength virtual physical test system.

[0040] Real-time matching of virtual and real fusion also includes shooting video information of the test process of the ultimate strength physical test of the hull structure, among which,

[0041] The video information of the ultimate strength physical test of the hull structure is imported into the 3D virtual model system and displayed in a visual window.

[0042] The visual display includes a state visual display based on real-time matching of the measured load of the ultimate strength physical test data and the ultimate strength simulation test results.

[0043] A virtual-real fusion method for an ultimate strength test of a hull structure is provided, wherein for a hull structure, real test data of an ultimate strength real physical test of the hull structure and / or simulated test data of an ultimate front-end simulated physical test of the hull structure are obtained, wherein:

[0044] The required virtual-reality fusion is performed on the real test data and the simulation test data using the above virtual-reality fusion system.

[0045] The advantages of the present invention are as follows: the real physical test information (measured strain, displacement, load, video monitoring) of the real physical test of ultimate strength and the simulation test information (simulated strain, displacement, load, three-dimensional structural response) of the finite element calculation of ultimate strength are integrated into the constructed virtual physical test system of the ultimate strength of the hull structure, which is conducive to the realistic presentation of the ultimate strength test of the ship structure and greatly enhances the visualization and reproducibility of the test.

[0046] The present invention utilizes the real-time reconstruction of the response field in the virtual-reality fusion and the real-time matching of the virtual-reality fusion to effectively guide the implementation of physical experiments and improve the degree of refinement of the experiments. In view of the problem that traditional video surveillance can only monitor the external information of the test object during the experiment, the video information of the test process is integrated, and the internal response state of the structure can be monitored in real time in the virtual space during the experiment. All internal and external state information of the test object can be accurately grasped without entering the test site, which greatly improves the amount of information obtained during the experiment while ensuring safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 This is a system block diagram of an embodiment of the virtual-reality fusion system of the present invention.

[0048] Figure 2 This is a schematic diagram of an embodiment of the virtual-real fusion of the present invention.

[0049] Figure 3 The flowchart of an embodiment of the real-time reconstruction of the structural response field of the present invention is shown.

[0050] Figure 4 The present invention is a flowchart of an embodiment of data analysis of ultimate strength simulation test results. DETAILED DESCRIPTION

[0051] The present invention will be further described below with reference to specific drawings and embodiments.

[0052] In order to effectively realize data fusion of the ultimate strength of the hull structure and improve the refinement of the ultimate strength test of the hull structure, a virtual-real fusion system for the ultimate strength test of the hull structure is provided in one embodiment of the present invention, including:

[0053] A high-fidelity virtual modeling module is used to construct a three-dimensional virtual model for the ultimate strength test of the hull structure, wherein the constructed three-dimensional virtual model includes at least a three-dimensional model of a virtual physical test scene for constructing a virtual physical test scene and a three-dimensional model of an ultimate strength virtual physical test for constructing an ultimate strength virtual physical test of the hull structure;

[0054] A virtual assembly module, which builds a virtual physical test system for the ultimate strength of a hull structure based on the three-dimensional model of the virtual physical test scene and the three-dimensional model of the ultimate strength virtual physical test constructed in the high-fidelity virtual modeling module. The constructed virtual physical test system for the ultimate strength of a hull structure includes a virtual physical test scene and an ultimate strength virtual physical test platform system based on the virtual physical test scene.

[0055] A virtual-real data fusion module is used to fuse the real physical test information of the ultimate strength of the hull structure and / or the ultimate strength simulation calculation information of the hull structure on the above-mentioned virtual physical test system of the ultimate strength of the hull structure, so as to realize the response field reconstruction of the ultimate strength test of the hull structure;

[0056] The virtual decision-making and prediction module is used to display the above-mentioned hull structure ultimate strength virtual physical test system and / or the hull structure ultimate strength virtual physical test system after the response field is reconstructed.

[0057] A virtual-real fusion system for the ultimate strength test of hull structures. Figure 1 An embodiment is shown in FIG. The virtual-reality fusion system generally includes a high-fidelity virtual modeling module, a virtual assembly module, a virtual-reality data fusion module, and a virtual decision-making and prediction module. The following details the high-fidelity virtual modeling module, the virtual assembly module, the virtual-reality data fusion module, and the virtual decision-making and prediction module.

[0058] Figure 1 In the embodiment, the high-fidelity virtual modeling module includes a virtual structural test platform, a virtual loading system, a virtual test fixture and a virtual sensor unit; wherein,

[0059] A virtual structural test platform is used to build a virtual physical test scene. The three-dimensional model of the virtual physical test scene in the virtual structural test platform includes a structural test platform model, a test plant model, a hydraulic pump source model, a cooling system model, and a driving model;

[0060] The virtual loading system includes load loading equipment models of the 1000kN-30MN series;

[0061] The virtual test fixture includes a reaction frame model, a beam model, a tie rod model and an anchor bolt model;

[0062] The virtual sensor unit includes a displacement sensor model, a force sensor model, a strain sensor model and / or an image sensor model.

[0063] During specific implementation, the three-dimensional virtual model in the high-fidelity virtual modeling module can be constructed and stored using existing commonly used methods. For example, industrial design software such as UG and ProE can be used to complete the basic geometric model construction, and then 3dmax can be used to map and render the basic model. Finally, uinty3d can be used to add physical properties such as mass, gravity, and elasticity to the model. The specific method and process of constructing the three-dimensional virtual model can be selected according to needs so that the required three-dimensional virtual model can be constructed.

[0064] When integrating the virtual and real worlds into the ultimate strength of a hull structure, the constructed 3D virtual model includes at least a 3D model of the virtual physical test scenario and a 3D model of the ultimate strength virtual physical test. The 3D model of the virtual physical test scenario is described above as an example; the ultimate strength virtual physical 3D model generally includes the aforementioned virtual loading system, virtual test fixtures, and virtual sensor units. Therefore, the 3D virtual model within the high-fidelity virtual modeling module is primarily used to construct the ultimate strength virtual physical test system for the hull structure described below.

[0065] In one embodiment of the present invention, the virtual assembly module relies on the high-fidelity virtual modeling module, that is, a virtual physical test system for the ultimate strength of the hull structure is built based on the three-dimensional model of the virtual physical test scene and the three-dimensional model of the ultimate strength virtual physical test. The method and process of building the virtual physical test system for the ultimate strength of the hull structure can be selected according to needs, so as to obtain the required virtual physical test system for the ultimate strength of the hull structure.

[0066] During specific implementation, the constructed virtual physical test system for the ultimate strength of the hull structure generally includes a virtual physical test scene and an ultimate strength virtual physical test platform system based on the virtual physical test scene; wherein, the virtual physical test scene is used to simulate the scene or environment of the ultimate strength physical test, and the ultimate strength virtual physical test platform system can be used to simulate the ultimate strength physical test state of the hull structure, and the specific requirements shall be based on whether it can meet the ultimate strength physical test simulation of the hull structure.

[0067] In one embodiment of the present invention, the virtual-real data fusion module specifically fuses the real physical test information of the ultimate strength of the hull structure and / or the ultimate strength simulation calculation information of the hull structure, and reconstructs the ultimate strength virtual physical test system of the hull structure.

[0068] Figure 1 The data sources used by the virtual-real data fusion module include simulation results, physical test data, and video image information. This data allows for the reconstruction of the structural response field, which typically includes strain, displacement, and stress fields. The specific process of virtual-real fusion is described in detail below.

[0069] In one embodiment of the present invention, when the virtual-real data fusion module is performing virtual-real fusion on the hull structure ultimate strength virtual physical test system, the virtual-real fusion includes reconstructing measured strain information in a real physical test of the ultimate strength of a hull structure on the hull structure ultimate strength virtual physical test system, wherein the virtual-real fusion method includes:

[0070] For the hull structure, determining the strain sampling point distribution of the hull structure in a real physical test of the ultimate strength, and establishing a theoretical strain-displacement correspondence relationship of the hull structure;

[0071] Based on the theoretical strain-displacement correspondence established above, in the actual physical test of the ultimate strength of the hull structure, the sampling point displacement and sampling point stress of the current strain sampling point based on the unit measured strain information sampled at each strain sampling point are determined;

[0072] Generate a structural response field of the hull structure during a real physical test of ultimate strength based on the measured strain information of all strain sampling points, the displacement of the sampling points corresponding to all strain sampling points, and the stress of the sampling points. The structural response field includes strain, displacement, and stress fields.

[0073] For the virtual physical test system of the ultimate strength of the hull structure, the required structural response field is reconstructed in real time based on the structural response field obtained above, so as to load the real-time displacement stress field information in the real physical test of the ultimate strength of the hull structure on the virtual physical test system of the ultimate strength of the hull structure.

[0074] For the fusion of virtual and real, Figure 2 It can be seen that it includes real-time reconstruction of the structural response field, wherein the structural response field reconstruction specifically refers to the real-time response information of the hull structure three-dimensional model in the hull structure ultimate strength virtual physical test system obtained by reconstructing the measured strain information based on the finite discrete strain sensor.

[0075] The fusion process requires measured strain information from the hull structure during real-world ultimate strength physical testing. To obtain this information, several strain sensors are installed on the hull structure. These sensors can be of commonly used types. The type and distribution of these sensors on the hull structure can be selected based on actual needs, ensuring that the measured strain information is captured. Once these sensors are installed, the distribution of strain sampling points corresponding to the hull results during the real-world ultimate strength physical testing can be determined.

[0076] Since strain sensors can only obtain strain information at the strain sampling point, in order to obtain displacement and stress fields, it is necessary to establish a theoretical strain-displacement correspondence between the hull structure. That is, using the established theoretical strain-displacement relationship and the strain information of each strain sampling point, the displacement and stress of the sampling point corresponding to the strain sampling point can be determined.

[0077] The sampling point displacement specifically refers to the displacement of the load-applying device under the applied load when a load is applied to the hull structure. The sampling point stress specifically refers to the sampling point stress corresponding to the unit strain information detected by the sampling point strain sensor of the hull structure. That is, after determining the unit strain information, the sampling point stress corresponding to the unit strain information can be obtained. The correspondence between the unit strain information and the sampling point stress is consistent with the existing knowledge, and the ability to determine the sampling point stress is the basis.

[0078] After using multiple strain sensors to collect the measured strain information of the unit of the hull structure under the ultimate strength physical test, the structural response field of the hull structure during the ultimate strength real physical test can be generated based on the measured strain information of the unit of all strain sampling points, the sampling point displacements corresponding to all strain sampling points, and the sampling point stresses.

[0079] During the actual physical testing of the hull structure's ultimate strength, the structural response field in its current state can be obtained. This structural response field is correlated with the current state of the actual physical testing. Once this structural response field is obtained, existing technologies can be used to perform real-time reconstruction of the structural response field on the 3D hull structure model within the hull structure's ultimate strength virtual physical testing system. This allows the real-time displacement and stress field information from the hull structure's ultimate strength physical testing to be loaded onto the 3D hull structure model. In practice, reconstruction involves rebuilding the entire model.

[0080] After reconstruction, the real-time displacement stress field corresponding to the current state of the ultimate strength real physical test can be displayed on the three-dimensional hull structure model of the hull structure ultimate strength virtual physical test system, which can improve the refinement of the hull structure ultimate strength real physical test.

[0081] In one embodiment of the present invention, for a hull structure, a four-node inverse shell finite element of the hull structure based on a NURBS basis function is constructed, and a theoretical strain-displacement correspondence relationship of the hull structure is established based on the constructed four-node inverse shell finite element. The established theoretical strain-displacement correspondence relationship of the hull structure is:

[0082]

[0083] Where u is the theoretical displacement, n is the number of strain sampling points on the hull structure, and ε i is the unit theoretical strain information of the i-th strain sampling point, N i (ξ) is the NURBS basis function of the i-th strain sampling point, and ξ is the parameter coordinate of the hull structure at the strain sampling point.

[0084] As can be seen from the above description, after determining the strain sampling points on the hull structure, a four-node inverse shell finite element based on the NURBS basis function is constructed. This is achieved by using the iFEM (inverse finite element method) method and establishing a theoretical strain-displacement relationship for the hull structure based on the four-node inverse shell finite element. This theoretical strain-displacement relationship facilitates the determination of subsequent sampling point displacements.

[0085] In one embodiment of the present invention, when generating the structural response field of the hull structure during the ultimate strength real physical test, the structural response field includes a linear structural response field with constant stiffness and a nonlinear structural response field with varying stiffness, wherein:

[0086] When generating a linear structural response field, this includes:

[0087] For any strain sampling point, construct the least square error function between the measured strain information of the unit and the theoretical strain information of the unit at the strain sampling point;

[0088] Taking a minimum value of the constructed least squares error function based on the least squares error function to determine a sampling point displacement unit matrix of the current strain sampling point;

[0089] Assemble the sampling point displacement element matrices of all strain sampling points to form the overall matrix of the hull structure;

[0090] The overall matrix of the hull structure is analyzed to generate a linear structural response field, where the generated linear structural response field includes the hull strain, hull stress, and displacement of the hull under the current ultimate strength physical test state.

[0091] In practice, when applying a load to the hull structure, a relationship between load, stiffness, and displacement can be derived. When stiffness exhibits a linear transformation, the ultimate strength physical test is in the linear phase. When stiffness changes from the linear phase, the ultimate strength physical test is in the nonlinear phase. Generally, in the linear phase, stiffness remains essentially constant or varies within an acceptable range. In the nonlinear phase, stiffness differs from that in the linear phase.

[0092] For any strain sampling point, the strain sensor of the strain sampling point is arranged on the upper and lower surfaces of the centroid of the constructed four-node inverse shell finite element. The upper surface strain information can be obtained according to the measured strain information of the element at the strain sampling point. And the lower surface strain information Among them, ε xx is the in-plane strain, ε yy is the strain perpendicular to the panel, γ xy is the shear strain.

[0093] Surface strain information And the lower surface strain information The surface strain is converted into plane strain e and bending strain k using the following formula, where h is the unit thickness.

[0094]

[0095]

[0096] Where n is the number of strain sensors deployed on the hull structure, is the plane strain corresponding to the measured strain information of the j-th strain sensor unit, is the bending strain corresponding to the strain information measured by the jth strain sensor unit. The unit thickness h specifically refers to the thickness of the structure where the unit is divided. Generally, in real physical tests of the ultimate strength of hull structures, the thickness of the hull structure is fixed, that is, a constant.

[0097] The least square error function of the measured strain information of the unit and the theoretical strain information of the unit at the strain sampling point is constructed, and then:

[0098]

[0099] Among them, Φ i To construct the least squares functional error function of the i-th strain sampling point, u i is a vector containing the nodal degrees of freedom; the surface strain, bending strain and transverse shear strain components are e, k, and g respectively. In actual tests, the shear strain can be ignored; ω m ,ω b ,ω sThese are weight coefficients associated with the three strain components, controlling the consistency between the numerical results and the experimental strain data. Weight coefficients can generally be obtained using common fitting methods. The specific fitting method for determining the weight coefficients can be selected based on the needs, with the desired weight coefficients being the most important.

[0100] Since the shear strain is negligible, the measured strain information of the element is substituted into the least squares error equation, which can be transformed into the sum of two normalized Euclidean norms as shown below:

[0101]

[0102] in,· 2 is the square operation of the calculated norm, and the integration domain Ai is the entire area of ​​the strain sampling point. The partial derivative of the least squares error function with respect to the displacement vector is calculated and set equal to 0. The minimum value of the least squares error function is solved as shown in the following formula:

[0103]

[0104] Then it can be transformed into the equilibrium equation. At this time, the sampling point displacement unit matrix of the i-th strain sampling point is obtained, that is, k e u e =f e , where k e is the stiffness, u e is the displacement, f e For load.

[0105] After obtaining the displacement matrix of the sampling points, for complex curved structures, the local coordinate systems established within each element have different orientations. Therefore, it is necessary to uniformly transform each element's local coordinate system to the global coordinate system. Incorporating structural displacement boundary constraints, deformation coordination conditions are ensured between each inverse element within the structure, thereby solving for the nodal degrees of freedom of all elements. Finally, the element matrix in the global coordinate system is used to construct the overall matrix of the hull structure according to standard finite element assembly procedures.

[0106]

[0107] Among them, T e is the coordinate transformation matrix, K is the hull structure stiffness matrix, F is the hull structure load matrix, and U is the hull structure displacement matrix. For a certain hull structure, the coordinate transformation matrix T e It can be obtained by adopting existing commonly used technical means.

[0108] After obtaining the overall matrix of the hull structure, the overall matrix of the hull structure is analyzed using technical means commonly used in this technical field to generate a linear structural response field. The generated linear structural response field includes the hull strain, hull stress and displacement when the load is applied under the current ultimate strength physical test state.

[0109] In one embodiment of the present invention, generating a nonlinear structural response field includes:

[0110] Determine the load range of the hull structure in the real physical test of the ultimate strength;

[0111] Under each load segment, the overall matrix of the hull structure under each load segment is determined by generating a linear structural response field;

[0112] The overall matrix of the hull structure is analyzed to generate a nonlinear structural response field under the current load segment. The generated nonlinear structural response field includes the hull strain, hull stress and displacement of the hull under the current ultimate strength physical test state.

[0113] For a hull structure, the test conditions for a real-world physical test of its ultimate strength can be determined, such as the load range during the test. During load application, the stiffness under the current loading state can be determined. If the stiffness is consistent with the previous stiffness, the structure is in the linear phase; otherwise, it enters the nonlinear phase. Once in the nonlinear phase, the remaining load range remains in the nonlinear phase.

[0114] Once the nonlinear phase is reached, in order to accurately generate the nonlinear structural response field, one embodiment of the present invention decomposes the remaining loading process into multiple load segments. Each load segment utilizes a linear iFEM method, specifically generating a linear structural response field to determine the overall hull structure matrix for each load segment. The load segment division specifically ensures that the stiffness within each segment exhibits a linear phase characteristic.

[0115] The overall hull structure matrix for each load segment can be obtained by referring to the above description and will not be repeated here. In practice, after analyzing the overall hull structure matrix and generating the nonlinear structural response field for the current load segment, the real-time linear displacement-strain increment can be determined.

[0116] After obtaining the overall matrix of the hull structure for all load segments, according to the above description, the structural response field of the hull structure during the ultimate strength real physical test is generated. The specific process of generating the structural response field can be referred to Figure 3 The process shown.

[0117] In one embodiment of the present invention, when the virtual-real data fusion module is fusion-enhanced on the hull structure ultimate strength virtual physical test system, the virtual-real fusion includes real-time matching virtual-real fusion, wherein:

[0118] The real-time matching virtual-real fusion at least fuses the simulation test results of the finite element calculation of the ultimate strength of the hull structure with the real test data of the real physical test of the ultimate strength of the hull structure on the hull structure ultimate strength virtual physical test system;

[0119] The real-time matching of virtual-reality fusion includes real-time comparison of the simulated load-displacement curve of the ultimate strength finite element calculation and the measured load-displacement curve of the ultimate strength real physical test, as well as real-time matching of the measured load based on the ultimate strength real physical test and the ultimate strength finite element calculation results on the ultimate strength virtual physical test system of the hull structure.

[0120] Depend on Figure 2 It can be seen that when integrating virtual and real, it can also include real-time matching of virtual and real fusion. Real-time matching of virtual and real fusion is to integrate the simulation test results of the finite element calculation of the ultimate strength of the hull structure with the real test data of the real physical test of the ultimate strength of the hull structure on the virtual physical test system of the ultimate strength of the hull structure.

[0121] The specific process of implementing the matching virtual-real fusion is described in detail below.

[0122] In one embodiment of the present invention, when the measured load based on the ultimate strength real physical test and the simulated load based on the ultimate strength finite element calculation are matched and integrated in real time, the process includes:

[0123] For any measured load F, the load data F′ is traversed frame by frame in the ultimate strength simulation test results. Based on the principle of minimizing FF′, all numerical simulation result data in the corresponding frame are extracted to be reconstructed and displayed on the hull structure ultimate strength virtual physical test system.

[0124] In specific implementation, when the finite element simulation calculation software is used to generate the ultimate strength simulation test results, the ultimate strength simulation test results contain multiple frames, and one frame corresponds to a simulation calculation load data F'. Therefore, the measured load F is subtracted from the load data F' of each frame, and the simulation result of the corresponding frame when the difference between the two is the smallest is called and displayed on the system, that is, reconstruction display is achieved.

[0125] In specific implementation, when matching virtual and real fusion in real time, the ultimate strength simulation test results are generated by finite element simulation calculation software, among which,

[0126] When the finite element simulation calculation software generates the ultimate strength simulation test results, the test conditions generated by the simulation are consistent with the test conditions of the ultimate strength physical test on the hull structure;

[0127] When matching virtual and real fusion in real time, first perform the required data analysis on the ultimate strength simulation test results generated by the finite element simulation software;

[0128] The data analysis process of the ultimate strength simulation test results includes data reading steps, data lightweighting steps, general data architecture construction steps and Unity3d rendering steps.

[0129] In one embodiment of the present invention, the finite element simulation calculation software includes finite element simulation software abaqus;

[0130] When executing the data reading step, the CAE result file of the finite element simulation software Abaqus is read;

[0131] When executing the data lightweighting step, the redundant data in the read CAE result file is deleted and the retained nodes are numbered sequentially.

[0132] Figure 4 A flowchart for data analysis of ultimate strength simulation test results is shown in Figure 1. Specifically, the data reading step is for the finite element simulation software Abaqus. The ODB result file of the finite element simulation software Abaqus consists of two parts: model data and result data. The model data includes the name of the finite element model, the calculation instance, the material, the node number and its three-dimensional coordinates, the element number and type, etc. The result data includes all the calculation results, such as stress, strain, displacement, load, etc., for each calculation frame in each calculation analysis step.

[0133] Taking displacement data analysis as an example, we first import the corresponding Python file library through the "from odbAccess import *" statement. Then, we go from the odb object to the calculation instance object, further from the calculation instance object to the analysis step object, and then from the analysis step object to the frame object. Finally, we obtain the displacement of all nodes in the field output object. The specific functions are shown in the following table.

[0134] Simulation calculation result odb file data structure

[0135]

[0136]

[0137] The data lightweighting step is specifically used to lightweight the simulation calculation result data. There is a phenomenon of disordered numbering of units and nodes in the simulation model result file, which leads to a large number of redundant nodes under the same spatial coordinates during the result file parsing process, affecting the rendering efficiency in the virtual-reality fusion test system. In one embodiment of the present invention, by traversing each node and its relationship with the unit, duplicate nodes, grid boundaries and other spatial redundant data are deleted, and the nodes are renumbered in sequence. During specific implementation, the technical means commonly used in this technical field can be used to determine and delete duplicate nodes, grid boundaries and other spatial redundant data, and the specific technical means for determination and deletion can be selected according to needs.

[0138] The steps for building a general data architecture specifically involve designing a corresponding function library and data variables for the basic data structure of simulation calculation results. This allows for the storage and management of all simulation calculation data, facilitating subsequent calls to virtual-reality fusion during the experiment. The simulation calculation data structure primarily includes the name, analysis step, unit, node, and result data. The cae_model function stores and manages model data such as the simulation model's name, analysis step, grid node location, number, and associated units. The cae_result function stores and manages the simulation model's result data, such as stress, strain, displacement, and load. The specific function library and key member variables are shown in the table below.

[0139]

[0140]

[0141] The Unity3D rendering is used to generate, render, and reconstruct visualizations of simulation results data within the virtual-reality fusion test system. Using the Mesh object within the Mesh Filter component within Unity3D, the simulation model node coordinates stored in the general data architecture are assigned to the Mesh object's triangle mesh vertex array, Vertices. The simulation model's node sequence and unit numbering are assigned to the Mesh object's vertex construction order index array, Triangles. The simulation model's maximum and minimum stress values ​​are assigned to the Mesh object's color array, Colors. This enables visualization of the simulation results on the ultimate strength virtual physical test platform system within the ship structure ultimate strength virtual physical test system.

[0142] In the specific implementation, Unity3D rendering is used to visualize the finite element simulation calculation results on the ultimate strength virtual physical test platform system. The specific method and process are consistent with the existing ones and will not be repeated here.

[0143] As can be seen from the above description, when performing ultimate strength finite element calculations and actual physical tests on a hull structure, corresponding simulated load-displacement curves and measured load-displacement curves can be obtained. The obtained simulated load-displacement curves and measured load-displacement curves are consistent with existing ones. Generally, the horizontal axis of the curve is displacement, and the vertical axis is load. Because the ultimate strength finite element calculations and actual physical tests use the same test conditions, the obtained simulated load-displacement curves and measured load-displacement curves can correspond.

[0144] During specific implementation, the corresponding data of the simulated load-displacement curve and the measured load-displacement curve are imported into the virtual data fusion module, so that the real-time comparison between the simulated load-displacement curve of the ultimate strength finite element calculation and the measured load-displacement curve of the ultimate strength real physical test can be achieved.

[0145] In one embodiment of the present invention, the real-time matching of virtual-real fusion further includes shooting video information of the test process of the ultimate strength physical test of the hull structure, wherein:

[0146] The video information of the ultimate strength physical test of the hull structure is imported into the 3D virtual model system and displayed in a visual window.

[0147] The visual display includes a state visual display based on real-time matching of the measured load of the ultimate strength physical test data and the ultimate strength simulation test results.

[0148] During specific implementation, the classification and processing integration of the video image information is connected to the virtual-reality fusion system of the present application through a network cable and a local area network communication protocol. The video image information is generally controlled by a monitoring host, and the monitoring host is accessed to obtain the stream address to obtain the real-time video signal to be imported into the virtual-reality fusion of the present invention, and finally displayed in the form of a visual window.

[0149] In specific implementation, video fusion actually introduces video monitoring of real physical tests of the ultimate strength of the hull structure into the system, that is, real-time signals are read through the IP address of the camera, and then displayed in real time within the virtual-reality fusion system of the present invention, so as to achieve the goal of not having to switch to the video monitoring software to view the on-site test status during the test.

[0150] For the virtual decision-making and forecasting module, Figure 1Specifically, it includes virtual-reality data comparison and analysis technology, virtual-reality fusion demonstration technology, and VR scene roaming of the entire test process; among them, virtual-reality data comparison and analysis technology, virtual-reality fusion demonstration technology, and VR scene roaming of the entire test process can be implemented by existing commonly used technical means. For example, the virtual-reality data comparison and analysis technology can be used to compare the above-mentioned simulated load-displacement curve with the measured load-displacement curve, and the virtual-reality fusion demonstration technology can be used to achieve real-time matching of simulated loads and virtual-reality fusion; for the video information of the test process, the VR scene roaming of the entire test process can be used to achieve VR visualization.

[0151] In summary, a virtual-real fusion method for the ultimate strength test of a hull structure is provided, which obtains, for a hull structure, real test data of a real physical test of the ultimate strength of the hull structure and / or simulated test data of a simulated physical test of the ultimate front end of the hull structure, wherein:

[0152] The required virtual-reality fusion is performed on the real test data and the simulation test data using the above virtual-reality fusion system.

[0153] In addition, during the specific integration work, the corresponding work process includes the following steps:

[0154] S1. Based on the physical test plan, the test personnel installed the physical test model, physical test supporting tooling, and physical sensors to complete the construction of the physical test system;

[0155] S2. The test personnel select a virtual test model and virtual test device in the high-fidelity virtual modeling module based on the physical test, assemble them through the virtual assembly module, install virtual sensors on the virtual test model, and connect the virtual test data acquisition instrument through network hardware to complete the construction of the virtual test system;

[0156] S3. Testers began the ultimate strength physical test of the hull structure. They imported the physical measured data and virtual simulation data through the virtual-real data fusion module and reconstructed the test model's structural response field based on the measured data.

[0157] S4. Based on the real-time virtual-real structural response comparison and key node real-time comparative analysis curves obtained by the virtual decision-making and prediction module, the test personnel monitor the internal state of the test model in real time and intelligently select the switching point of the physical test loading control mode to improve the refinement of the test;

[0158] S5. Test personnel conduct semi-physical tests through the virtual decision-making and prediction module, comprehensively analyze the physical test results and virtual test results, focus on analyzing the local structural response and damage evolution failure laws of the test model, identify the failure mode of the test model, and predict the structural performance boundary of the test model.

[0159] In summary, the integration of the real physical test information (measured strain, displacement, load, video monitoring) of the ultimate strength real physical test and the simulation test information (simulated strain, displacement, load, three-dimensional structural response) of the ultimate strength finite element calculation into the constructed hull structure ultimate strength virtual physical test system is conducive to the realistic presentation of the ultimate strength test of the ship structure and greatly enhances the visualization and reproducibility of the test.

[0160] The present invention utilizes the real-time reconstruction of the nonlinear stress field in the virtual-real fusion and the real-time matching of the virtual-real fusion to effectively guide the implementation of physical experiments and improve the degree of refinement of the experiments. In view of the problem that traditional video surveillance can only monitor the external information of the test object during the experiment, the video information of the test process is integrated, and the internal response state of the structure can be monitored in real time in the virtual space during the experiment. All internal and external state information of the test object can be accurately grasped without entering the test site, which greatly improves the amount of information obtained during the experiment while ensuring safety.

Claims

1. A virtual-real fusion system for ultimate strength testing of hull structures, characterized by: include: A high-fidelity virtual modeling module is used to construct a three-dimensional virtual model for the ultimate strength test of the hull structure, wherein the constructed three-dimensional virtual model includes at least a three-dimensional model of a virtual physical test scene for constructing a virtual physical test scene and a three-dimensional model of an ultimate strength virtual physical test for constructing an ultimate strength virtual physical test of the hull structure; A virtual assembly module, which builds a virtual physical test system for the ultimate strength of a hull structure based on the three-dimensional model of the virtual physical test scene and the three-dimensional model of the ultimate strength virtual physical test constructed in the high-fidelity virtual modeling module. The constructed virtual physical test system for the ultimate strength of a hull structure includes a virtual physical test scene and an ultimate strength virtual physical test platform system based on the virtual physical test scene. A virtual-real data fusion module is used to fuse the real physical test information of the hull structure ultimate strength and / or the ultimate strength simulation calculation information of the hull structure on the above-mentioned hull structure ultimate strength virtual physical test system to achieve the response field reconstruction of the hull structure ultimate strength test; A virtual decision-making and prediction module is used to display the virtual physical test system for the ultimate strength of the hull structure and / or the virtual physical test system for the ultimate strength of the hull structure after the response field reconstruction as required; When the virtual-real data fusion module is used to perform virtual-real fusion on the hull structure ultimate strength virtual physical test system, the virtual-real fusion includes reconstructing measured strain information in a real physical test of the ultimate strength of a hull structure on the hull structure ultimate strength virtual physical test system, wherein the virtual-real fusion method includes: For the hull structure, determining the strain sampling point distribution of the hull structure in a real physical test of the ultimate strength, and establishing a theoretical strain-displacement correspondence relationship of the hull structure; Based on the theoretical strain-displacement correspondence established above, in the actual physical test of the ultimate strength of the hull structure, the unit measured strain information sampled at each strain sampling point is used to determine the theoretical sampling point displacement and sampling point stress of the current strain sampling point based on the unit measured strain information; Generate a structural response field of the hull structure during a real physical test of ultimate strength based on the measured strain information of all strain sampling points, the theoretical sampling point displacements and sampling point stresses corresponding to all strain sampling points, wherein the structural response field includes strain, displacement and stress fields; For the virtual physical test system of the ultimate strength of the hull structure, the required structural response field is reconstructed in real time based on the structural response field obtained above, so as to load the real-time displacement stress field information in the real physical test of the ultimate strength of the hull structure on the virtual physical test system of the ultimate strength of the hull structure.

2. The virtual-reality fusion system for hull structure ultimate strength test according to claim 1 is characterized in that: The high-fidelity virtual modeling module includes a virtual structural test platform, a virtual loading system, a virtual test fixture and a virtual sensor unit; wherein, A virtual structural test platform is used to build a virtual physical test scene. The three-dimensional model of the virtual physical test scene in the virtual structural test platform includes a structural test platform model, a test plant model, a hydraulic pump source model, a cooling system model, and a driving model; The virtual loading system includes load loading equipment models of the 1000kN-30MN series; The virtual test fixture includes a reaction frame model, a beam model, a tie rod model and an anchor bolt model; The virtual sensor unit includes a displacement sensor model, a force sensor model, a strain sensor model and / or an image sensor model.

3. The virtual-reality fusion system for hull structure ultimate strength test according to claim 1 is characterized in that: For the hull structure, a four-node inverse shell finite element of the hull structure based on the NURBS basis function is constructed, and a theoretical strain-displacement correspondence relationship of the hull structure is established based on the constructed four-node inverse shell finite element. The established theoretical strain-displacement correspondence relationship of the hull structure is: Where u is the theoretical displacement, n is the number of strain sampling points on the hull structure, and ε i is the unit strain information of the i-th strain sampling point, N i (ξ) is the NURBS basis function of the i-th strain sampling point, and ξ is the parameter coordinate of the hull structure at the strain sampling point.

4. The virtual-reality fusion system for hull structure ultimate strength test according to claim 3 is characterized in that: When generating the structural response field of the hull structure during the ultimate strength real physical test, it includes the linear structural response field with constant stiffness and the nonlinear structural response field with varying stiffness, among which, When generating a linear structural response field, this includes: For any strain sampling point, construct the least square error function between the measured strain information of the unit and the theoretical strain information of the unit at the strain sampling point; Taking a minimum value of the constructed least squares error function based on the least squares error function to determine a theoretical sampling point displacement unit matrix of the current strain sampling point; Assemble the theoretical sampling point displacement element matrices of all strain sampling points to form the overall matrix of the hull structure; The overall matrix of the hull structure is analyzed to generate a linear structural response field, where the generated linear structural response field includes the hull strain, hull stress, and displacement of the hull under the current ultimate strength physical test state.

5. The virtual-reality fusion system for hull structure ultimate strength test according to claim 4 is characterized in that: When generating nonlinear structural response fields, this includes: Determine the nonlinear loading section of the hull structure in the real physical test of ultimate strength; Under each load segment, the overall matrix of the hull structure under each load segment is determined by generating a linear structural response field; The overall matrix of the hull structure is analyzed to generate a nonlinear structural response field under the current load segment. The generated nonlinear structural response field includes the hull strain, hull stress and displacement of the hull under the current ultimate strength physical test state.

6. The virtual-reality fusion system for hull structure ultimate strength test according to any one of claims 1 to 5, characterized in that: When the virtual-real data fusion module is used for virtual-real fusion on the hull structure ultimate strength virtual physical test system, the virtual-real fusion includes real-time matching of virtual-real fusion, wherein: The real-time matching virtual-real fusion at least fuses the simulation test results of the finite element calculation of the ultimate strength of the hull structure with the real test data of the real physical test of the ultimate strength of the hull structure on the hull structure ultimate strength virtual physical test system; The real-time matching of virtual-reality fusion includes real-time comparison of the simulated load-displacement curve of the ultimate strength finite element calculation and the measured load-displacement curve of the ultimate strength real physical test, as well as real-time matching of the measured load based on the ultimate strength real physical test and the ultimate strength simulation calculation results on the ultimate strength virtual physical test system of the hull structure.

7. The virtual-reality fusion system for ultimate strength test of hull structure according to claim 6 is characterized in that: When the measured load based on the ultimate strength real physical test and the simulated load of the ultimate strength simulation result are matched in real time, the virtual and real fusion is carried out, including: For any measured load F, the load data F′ is traversed frame by frame in the ultimate strength simulation test results. Based on the principle of minimizing |FF′|, all the numerical simulation result data in the corresponding frame are extracted to be reconstructed and displayed on the hull structure ultimate strength virtual physical test system.

8. The virtual-reality fusion system for ultimate strength test of hull structure according to claim 6 is characterized in that: Real-time matching of virtual and real fusion also includes shooting video information of the test process of the ultimate strength physical test of the hull structure, among which, The video information of the ultimate strength physical test of the hull structure is imported into the virtual-reality fusion test system, and the required visual display is performed in the form of a visual window; The visual display includes a state visual display based on real-time matching of ultimate strength physical test video information and ultimate strength simulation test results.

9. A virtual-real fusion method for ultimate strength testing of hull structures, characterized by: For a hull structure, actual test data of a real physical test of the ultimate strength of the hull structure and / or simulation test data of a finite element calculation of the ultimate strength of the hull structure are obtained, wherein: The virtual-reality fusion system of any one of claims 1 to 8 is used to perform the required virtual-reality fusion on the real test data and the simulation test data.

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