CN-122021166-A - Method and system for predicting rigidity and bearing capacity of plate-type node under bolt relaxation

Abstract

The invention provides a method and a system for predicting rigidity and bearing capacity of a plate-type node under bolt looseness, which relate to the technical field of computer simulation, and are characterized in that firstly, relevant information of the plate-type node is acquired to construct a finite element model; the method comprises the steps of configuring test equipment to develop a bolt loosening test, constructing a bolt pre-tightening force time-varying attenuation model, modifying a finite element model contact interface unit, embedding the time-varying attenuation model to finish coupling treatment to obtain the bolt loosening coupling finite element model, extracting key parameters to generate a plurality of groups of schemes to conduct numerical simulation to form a parameter association data set, selecting regression analysis methods to construct mathematical expressions according to the arrangement data, outputting plate-type node rotation rigidity and bearing capacity data based on specific time points and the bolt pre-tightening force attenuation data, accurately predicting the plate-type node rigidity and bearing capacity under bolt loosening, and effectively improving the safety and reliability of an engineering structure.

Inventors

• Tan Yilinke
• SHAO YONGBO
• MENG LINGZHAO
• GONG JUN

Assignees

• 西华大学

Dates

Publication Date

20260512

Application Date

20260202

Claims (10)

1. 1. The method for predicting the rigidity and the bearing capacity of the plate-type node under the loosening of the bolts is characterized by comprising the following steps: obtaining structural information, material mechanics data and bolting related data of the plate node, and constructing a plate node finite element model integrating stress response, geometric form change and contact interface action of the material; Configuring bolt loosening test equipment, setting different test conditions to start a test, recording test data of bolt pre-tightening force changing along with time, analyzing curve characteristics of the bolt pre-tightening force changing along with time based on the test data of the bolt pre-tightening force changing along with time, extracting parameter data related to an attenuation process, and constructing a time-varying attenuation model of the bolt pre-tightening force; Modifying a contact interface unit of the plate node finite element model, embedding pre-tightening force attenuation data output by the bolt pre-tightening force time-varying attenuation model into the contact interface unit of the plate node finite element model, establishing a parameter transmission channel between the plate node finite element model and the bolt pre-tightening force time-varying attenuation model, and completing coupling treatment to obtain a bolt loose coupling finite element model; Extracting key parameters affecting the rigidity and the bearing capacity of the plate-type node, generating a plurality of groups of parameter combination schemes, sequentially inputting a bolt relaxation coupling finite element model for numerical simulation, and recording corresponding rigidity change data and bearing capacity data of the plate-type node to form a parameter association data set; And (3) sorting all data in the parameter association data set, selecting an adaptive regression analysis method, and constructing a mathematical expression based on the association relation between the data, wherein the mathematical expression is based on specific time point data and bolt pretightening force attenuation data, and outputting corresponding plate node rotation stiffness data and bearing capacity data.
2. 2. The method for predicting rigidity and bearing capacity of a plate node under bolt relaxation according to claim 1, wherein the modifying the contact interface unit of the plate node finite element model embeds the pre-tightening force attenuation data output by the bolt pre-tightening force time-varying attenuation model into the contact interface unit of the plate node finite element model, establishes a parameter transmission channel between the plate node finite element model and the bolt pre-tightening force time-varying attenuation model, and completes coupling processing to obtain the bolt relaxation coupling finite element model, and comprises the following steps: Analyzing a parameter input format of a contact interface unit in the plate node finite element model, and extracting and defining a parameter type, a data format and an updating frequency which can be received by the contact interface unit; extracting the output parameter type of a bolt pre-tightening force time-varying attenuation model, screening pre-tightening force attenuation data related to the stress state of a contact interface unit, and sorting and defining the output format, data precision and output time interval of the pre-tightening force attenuation data; Comparing the difference points of the type, format and frequency of the parameters required by the contact interface unit and the parameters output by the pretightening force attenuation model, constructing a parameter conversion rule aiming at each difference point, and adjusting pretightening force attenuation data based on the parameter conversion rule to adapt to the parameter input requirement of the contact interface unit; Constructing a data conversion module based on a parameter conversion rule, wherein the data conversion module reads the pretightening force attenuation data and processes the pretightening force attenuation data according to the parameter conversion rule, and outputs adaptive pretightening force attenuation data which accords with the parameter receiving specification of the contact interface unit; Carrying out parameter interface transformation on a contact interface unit of the plate-type node finite element model, adding a data receiving port, establishing connection between the data receiving port and a data conversion module, receiving adaptive pretightening force attenuation data and updating stress parameters of the contact interface unit in real time; establishing a communication link between the bolt pre-tightening force time-varying attenuation model and the data conversion module, setting a verification mode of data transmission, and verifying pre-tightening force attenuation data in transmission; configuring parameter transmission channel test equipment, simulating a pretightening force attenuation data output process, transmitting data to a contact interface unit through a data conversion module, and recording data transmission delay time, parameter updating success rate and data matching accuracy rate; According to the data transmission delay time, the parameter updating success rate and the data matching accuracy rate of the test records, the conversion algorithm of the data conversion module and the data receiving port setting of the contact interface unit are adjusted, and the performance adjustment of the parameter transmission channel is realized through algorithm optimization and port configuration adjustment; Integrating the optimized parameter transmission channel between the plate node finite element model and the bolt pre-tightening time-varying attenuation model, starting the plate node finite element model and the bolt pre-tightening time-varying attenuation model to cooperatively operate, and monitoring parameter updating data of a contact interface unit and calculation operation data of the whole model; And through the cooperative operation of the parameter transfer data and the data matching result between the acquisition plate type node finite element model and the bolt pre-tightening time-varying attenuation model, the contact interface unit receives and applies the pre-tightening attenuation data, and finally the bolt loose coupling finite element model is obtained.
3. 3. The method for predicting rigidity and bearing capacity of a plate node under bolt relaxation according to claim 1, wherein the extracting key parameters affecting rigidity and bearing capacity of the plate node, generating a multi-group parameter combination scheme, sequentially inputting a bolt relaxation coupling finite element model for numerical simulation, recording corresponding rigidity change data and bearing capacity data of the plate node, and forming a parameter association data set, comprises: summarizing various parameters related to structural composition, material mechanics response data and bolting mode of the plate-type node, screening parameters with direct effects on rigidity formation and bearing capacity by combining data accumulated by engineering practice and records of related technical documents, and determining the parameters as key parameters; collecting value range data in engineering practical application aiming at each key parameter, and dividing a value interval by combining bolt relaxation test data and the computing capacity of a plate node finite element model; Adopting an orthogonal test construction method, selecting representative value points based on the value interval of each key parameter, and generating a plurality of groups of mutually non-repeated parameter combination schemes according to a parameter combination principle, wherein each group of parameter combination schemes comprises specific values of all key parameters; Numbering and sorting each group of parameter combination schemes, and establishing a parameter combination scheme list, wherein the number of each group of parameter combination schemes, the value of each key parameter and the corresponding engineering application scene reference are recorded in the parameter combination scheme list; Configuring a numerical simulation execution device, importing a bolt loose coupling finite element model, setting calculation accuracy, a convergence criterion and an output data type, and enabling the bolt loose coupling finite element model to output plate-type node rigidity change data and bearing capacity data; Inputting each group of parameter combination schemes to the bolt loosening coupling finite element model in sequence according to the numbering sequence of the parameter combination scheme list, starting numerical simulation calculation and recording the starting time and the ending time; in the numerical simulation calculation process of each group, plate node rigidity change data and bearing capacity data output by a bolt loose coupling finite element model are collected in real time, the collected plate node rigidity change data and bearing capacity data are collated, the number of each group of parameter combination scheme is associated with the corresponding collected plate node rigidity change data and bearing capacity data, and a one-to-one corresponding target association record is formed; summarizing all the target associated records according to the numbering sequence of the parameter combination scheme list to form a parameter associated data set containing a plurality of groups of parameter combinations and corresponding plate-type node rigidity change data and bearing capacity data.
4. 4. The method for predicting rigidity and bearing capacity of a plate-type node under bolt loosening according to claim 1, wherein the sorting parameters are associated with all data in a data set, selecting an adaptive regression analysis method, and constructing a mathematical expression based on an association relationship between the data, comprises: Classifying and sorting the data in the parameter association data set according to the key parameter type, the specific time point data and the bolt pretightening force attenuation data, and counting the quantity, the value range and the distribution characteristics of various data to form a data classification statistical report; Collecting applicable scene data and fitting result data of a plurality of regression analysis methods based on data distribution characteristics and association relations in the data classification statistical report, comparing the application characteristics with applicable limiting characteristics, and screening regression analysis methods of an adaptation parameter association data set; Setting dependent variables and independent variables of regression analysis, respectively setting plate-type node rotation stiffness data and bearing capacity data as dependent variables, setting key parameter data, specific time point data and bolt pretightening force attenuation data as independent variables, and establishing a corresponding relation between each dependent variable and each independent variable; Preprocessing the classified self-variable data and dependent variable data, removing abnormal values and repeated data, performing uniform scale processing to obtain a preprocessed data set, constructing a regression model frame based on a selected regression analysis method and the preprocessed data set, setting initial parameters and constraint conditions, and setting a model solving target to determine regression coefficients; Substituting the preprocessed data set into a regression model framework, and calculating and solving undetermined coefficients to obtain a preliminary regression equation reflecting the basic association trend of the independent variable and the dependent variable; Substituting partial data in the parameter association data set into a preliminary regression equation to calculate dependent variable prediction data as a verification data set, and comparing the dependent variable prediction data with actual dependent variable data in the verification data set; According to the deviation between the predicted value and the actual value, parameter setting and constraint conditions of a regression model frame are adjusted, coefficients of a preliminary regression equation are optimized, and the deviation between dependent variable predicted data and actual dependent variable data in a verification data set is reduced; And repeating the model frame optimization and data verification processes until the deviation of the predicted data and the actual data of the preliminary regression equation is in a preset range, determining the optimized preliminary regression equation as a final mathematical expression, marking the meaning of each variable, the data input format and the expression form of an output result, and enabling the final mathematical expression to output corresponding plate-type node rotation stiffness data and bearing capacity data based on the data of a specific time point and the bolt pretightening force attenuation data.
5. 5. The method for predicting rigidity and bearing capacity of a plate node under bolt relaxation according to claim 1, wherein the steps of obtaining structural information, material mechanics data and bolting related data of the plate node, and constructing a plate node finite element model integrating stress response, geometric shape change and contact interface action of a material comprise the following steps: acquiring plate shape and size of plate type nodes, arrangement positions of bolts and structural information of node connection modes, wherein the material mechanics data comprise elastic response data and plastic deformation data of the plates, and tensile deformation data and shear deformation data of the bolts; Collecting roughness data of a contact surface between a bolt and a plate, size data of a contact area and initial contact pressure data after the bolt is screwed; Importing structure formation information into finite element analysis software, establishing a geometric model of a plate node according to an actual proportion, and restoring geometric forms and relative position relations of plates, bolts and connecting parts; Distributing the material mechanical data to corresponding parts in the geometric model of the plate node, and endowing corresponding material constitutive model parameters for each part; Establishing a contact interface model in a geometric model of the plate type node based on the roughness data of the contact surface, the size data of the contact area and the initial contact pressure data after the bolts are screwed, defining an interaction mode of the contact surface, and setting a force transmission path of the contact interface so that the contact interface model simulates the actual contact condition between the bolts and the plate; setting simulation parameters of stress response of the material in a geometric model of the plate-type node, inputting stress-strain relation data of the material, and realizing the simulation of elastic and plastic response of the material under different stress states; Setting simulation setting of geometric form change, and adjusting solving setting of a geometric model of the plate node to enable the geometric model of the plate node to present displacement change and deformation form of the component in the stress process; optimizing the calculation parameters of the contact interface model, and adjusting the contact stiffness and friction related settings to enable the force transfer simulation to keep corresponding to the actual situation; Integrating stress response simulation, geometric form change simulation and contact interface action simulation of the material, and performing integral debugging on a geometric model of the plate-type node to enable all parts to cooperatively operate to simulate mechanical behaviors of the plate-type node, so as to finally obtain a plate-type node finite element model integrating stress response, geometric form change and contact interface action of the material; The configuration bolt relaxation test equipment sets up different test conditions and starts the test, records the test data of bolt pretightning force along with time variation, based on the test data of bolt pretightning force along with time variation, analyzes the curve characteristic of bolt pretightening force along with time variation, extracts the parameter data related to the attenuation process, constructs the time-varying attenuation model of bolt pretightening force, and comprises: Selecting a common engineering bolt as a test sample, keeping the materials and specifications of the test sample corresponding to those of the bolt in actual engineering application, and eliminating the test sample with defects; Configuring bolt relaxation test equipment comprising a bolt fixing mechanism, a pretightening force applying mechanism, a pretightening force measuring mechanism and an environment control mechanism; Setting a plurality of groups of test schemes, wherein each group of test schemes comprises different temperature environment condition data, humidity environment condition data and different initial pretightening force related data; Installing test samples to bolt loosening test equipment according to each group of test schemes, applying a set initial pretightening force, and starting the bolt loosening test equipment to execute a bolt loosening test after the bolt loosening test equipment is stabilized; Recording the pretightening force value, the measurement time point and the corresponding environmental parameters of a test sample in real time in the test process, and finishing the recorded data after the test is finished to form test data of the bolt pretightening force changing along with time, and storing the test data in groups according to each group of test schemes; Trend analysis is carried out on test data of the bolt pretightening force corresponding to each group of test schemes along with time, the change trend of pretightening force values along with time is observed, attenuation stages are identified, and attenuation data of different stages are recorded; analyzing the internal action path of the attenuation of the pre-tightening force by combining the test data of the pre-tightening force of the bolt, the structural form data and the material mechanical response data of the bolt, and analyzing the influence mode of the bolt material deformation, the interaction of a thread pair and the change of a contact surface on the attenuation; extracting material mechanical response data, environment condition data and initial pre-tightening state data which influence pre-tightening force attenuation, respectively carrying out standardized processing, and establishing a corresponding relation between various data and pre-tightening force attenuation based on the standardized processed data; Selecting a mathematical model form describing the attenuation trend of the pre-tightening force along with time, taking standardized material mechanical response data, environment condition data and initial pre-tightening state data as input variables, taking pre-tightening force attenuation data as output variables, substituting test data of the bolt pre-tightening force along with time to solve model parameters, and constructing a bolt pre-tightening force time-varying attenuation model.
6. 6. The method for predicting rigidity and bearing capacity of a plate-type node under bolt loosening according to claim 2, wherein the adjusting the conversion algorithm of the data conversion module and the data receiving port setting of the contact interface unit according to the data transmission delay time, the parameter updating success rate and the data matching accuracy of the test record, and the performance adjustment of the parameter transmission channel is realized through algorithm optimization and port configuration adjustment comprises: carrying out statistical analysis on the data transmission delay time of the test record, calculating the average delay time, the maximum delay time and the minimum delay time under different parameter combinations, and identifying key factors comprising data conversion complexity and transmission protocol adaptation matching data; The conversion algorithm of the data conversion module is adjusted according to key factors comprising data conversion complexity and transmission protocol adaptation matching data, so that data processing steps are simplified, calculation logic is optimized, conversion speed is improved, and single-group data conversion time consumption is reduced; analyzing the parameter updating success rate data, counting the number of updating failures and corresponding failure scene data, and checking failure reasons comprising port compatibility matching data, data format matching data and transmission link connection data; According to failure reasons including port compatibility matching data, data format matching data and transmission link connection data, adjusting data receiving port setting of the contact interface unit, replacing an adaptive data transmission protocol, and optimizing receiving buffer size and data processing priority; evaluating the data matching accuracy, comparing the converted data with standard data required by a contact interface unit, identifying error types and occurrence frequencies, and analyzing error sources comprising parameter conversion rule perfected data and data precision standard data; perfecting a parameter conversion rule, supplementing corresponding conversion logic, and adjusting accuracy control parameters of the data conversion module to ensure that the accuracy of output data meets the requirements of a contact interface unit; The optimized parameter transmission channel test equipment is configured, the data transmission test is carried out again according to the original test scheme, and the new data transmission delay time, the parameter updating success rate and the data matching accuracy rate are recorded; Comparing the test data before and after optimization, evaluating the change of transmission efficiency data and stability data of the parameter transmission channel, and judging whether a preset optimization target comprising a delay time reduction amplitude and an update success rate improvement amplitude is met; if the preset optimization targets including the delay time reduction amplitude and the update success rate improvement amplitude are not met, repeating the adjustment steps, and further optimizing the conversion algorithm, the port setting and the parameter conversion rule until the test data meet the preset optimization targets including the delay time reduction amplitude and the update success rate improvement amplitude; And recording the optimized conversion algorithm parameters, port configuration parameters and conversion rule details of the parameter transmission channel to form a parameter transmission channel optimization report.
7. 7. The method for predicting rigidity and bearing capacity of a plate-type node under bolt loosening according to claim 4, wherein the regression analysis method for collecting applicable scene data and fitting result data of a plurality of regression analysis methods based on data distribution characteristics and association relations in a data classification statistical report, comparing the application characteristics and applicable limiting characteristics, and screening an adaptation parameter association data set comprises the following steps: extracting key information containing independent variables, dependent variable quantity, data distribution type, variable association characteristics and data dispersion characteristics from a data classification statistical report; Collecting common regression analysis methods including a linear regression method, a nonlinear regression method and a multiple regression method, collecting technical documents and application cases, and extracting applicable data types, premise assumptions and application limits; Selecting a public data set similar to the characteristics of the parameter associated data set according to each collected regression analysis method, performing fitting analysis, and recording convergence speed, fitting error and result stability data; Evaluating fitting result data of each method based on fitting analysis results, calculating statistical indexes comprising average errors and maximum errors, and comparing error levels of different methods; comparing the application characteristics and the applicable limiting characteristics of each method, and judging the adaptive data by combining the distribution characteristics and the association relation of the parameter association data set; At least two regression analysis methods with the adaptation data meeting the requirements are preliminarily screened, partial data of the parameter association data set are substituted for trial fitting, the calculation time consumption in the process of the trial fitting and the deviation situation of the fitting result and the actual data are recorded, the trial fitting effect data are compared, and the fitting result of the plate-type node rigidity data and the bearing capacity data is focused; And (3) comprehensively evaluating fitting precision, computing efficiency and stability by combining the fitting effect data, the computing efficiency data and the method usability data, and selecting an optimal regression analysis method to form a regression analysis method selection report comprising a collection process, a comparison result, fitting data and final selection method names and reasons.
8. 8. The method for predicting rigidity and bearing capacity of a plate-type node under bolt loosening according to claim 3, wherein the orthogonal test construction method is adopted, representative value points are selected based on the value interval of each key parameter, a plurality of sets of mutually non-repeated parameter combination schemes are generated according to the parameter combination principle, each set of parameter combination schemes comprises specific values of all key parameters, and the method comprises the following steps: after the value interval of each key parameter is determined, a value point selection mode is determined according to the type of the parameter, the continuous type parameter is selected equidistantly or non-equidistantly, and all possible key values are selected by the discrete type parameter; determining the type and specification of an orthogonal table based on an orthogonal test construction basic principle, and meeting the requirements of the number of key parameters and the number of valued points; Numbering the value points of each key parameter in sequence, corresponding to columns in an orthogonal table, wherein each column represents one key parameter, and each level in the column corresponds to one value point of the key parameter; selecting corresponding levels according to the arrangement rule of the orthogonal table, and combining to form a plurality of groups of preliminary parameter combination schemes which are not repeated and have representativeness; Sorting the preliminary parameter combination schemes according to the priorities of the actual application scenes of the engineering, checking the sorted preliminary parameter combination schemes, removing the preliminary parameter combination schemes which are logically contradictory or can not be realized, supplementing special parameter combination schemes which are not covered by an orthogonal table but possibly appear in the engineering, numbering and sorting all the finally determined parameter combination schemes, labeling the specific values of each key parameter and the corresponding engineering application scene reference, and forming a parameter combination scheme summary table containing scheme numbers, values of each key parameter, engineering scene reference and priority information.
9. 9. The method for predicting rigidity and bearing capacity of a plate node under loosening of a bolt according to claim 5, wherein the establishing a contact interface model in a geometric model of the plate node based on the roughness data of the contact surface, the size data of the contact area and the initial contact pressure data after tightening of the bolt, defining an interaction mode of the contact surface, setting a force transmission path of the contact interface, and enabling the contact interface model to simulate an actual contact condition between the bolt and the plate comprises: Extracting the roughness data of the contact surface, the size data of the contact area and the initial contact pressure data from the roughness data of the contact surface, the size data of the contact area and the initial contact pressure data after the bolts are screwed, classifying, sorting and marking corresponding contact parts and measuring conditions; positioning a contact area of a bolt and a plate in a geometric model of a plate node, accurately dividing a contact surface range to enable the geometric form to be consistent with an actual contact position, wherein the contact surface comprises a contact surface of a bolt head and the plate and a contact surface of a bolt rod and a plate hole wall; Setting microscopic geometric characteristics in a contact interface model according to the roughness data of the contact surface, and simulating the unevenness of the actual contact surface by defining surface roughness parameters; determining the calculation range and the grid division density of a contact interface model based on the size data of a contact area, wherein the inside of the contact area is divided by adopting an encrypted grid, and the non-contact area is divided by adopting a conventional grid; defining an interaction mode of a contact surface, and selecting a corresponding contact algorithm comprising a penalty function method and a Lagrange multiplier method according to material mechanical response data and contact conditions of the bolt and the plate; Setting a force transmission path of a contact interface, determining a transmission mode of a mechanical quantity, and setting an initial stress condition based on initial contact pressure data, wherein the mechanical quantity comprises contact pressure and friction force; integrating microscopic geometric features, grid division, interaction modes and force transmission path setting, constructing a preliminary contact interface model and embedding the preliminary contact interface model into a geometric model of the plate-type node; Independently debugging the preliminary contact interface model, applying a specific numerical load, observing stress distribution and displacement change, and verifying that the preliminary contact interface model presents interaction behavior of a contact surface; And (3) adjusting the surface roughness parameters, the grid density and the contact algorithm parameters of the preliminary contact interface model according to the debugging result, and combining the optimized preliminary contact interface model with the material attribute setting and the mechanical response simulation parameters of the geometric model of the plate node to complete the construction of the contact interface model.
10. 10. A system for predicting rigidity and bearing capacity of a plate-type node under bolt relaxation, comprising: A processor; a machine-readable storage medium storing machine-executable instructions for the processor; Wherein the processor is configured to perform the method of predicting stiffness and load bearing capacity of a bolt-on-loose panel node of any one of claims 1 to 9 via execution of the machine-executable instructions.

Description

Method and system for predicting rigidity and bearing capacity of plate-type node under bolt relaxation Technical Field The invention relates to the technical field of computer simulation, in particular to a method and a system for predicting rigidity and bearing capacity of a plate-type node under bolt relaxation. Background In many fields such as building structures, bridge engineering, mechanical equipment, etc., plate-type nodes are widely used as a common connection form in the construction of various structures. The panel joints are usually connected by bolts, the rigidity and load-bearing capacity of which directly affect the safety and stability of the overall structure. In practical engineering applications, bolting can be affected by a number of factors, where bolt loosening is a non-negligible problem. In the long-term service process of the bolt, the pretightening force of the bolt is gradually attenuated due to the effects of vibration, temperature change, alternating load and the like, so that the connection performance of the bolt is changed, and the rigidity and the bearing capacity of the plate-type node are further affected. At present, research on the rigidity and bearing capacity of plate-type nodes is mostly based on bolt connection under ideal conditions, namely, the bolt pretightening force is assumed to be unchanged. However, the above assumption has a large deviation from the actual situation, and the influence of the bolt looseness on the performance of the plate-type node cannot be accurately reflected. The existing research method often lacks of accurate simulation of the bolt loosening process, and is difficult to establish quantitative relation between bolt pretightening force attenuation and plate-type node rigidity and bearing capacity, so that adverse effects of bolt loosening cannot be fully considered in structural design and safety evaluation, and potential risks are brought to safe operation of an engineering structure. Disclosure of Invention In view of the above-mentioned problems, in combination with the first aspect of the present invention, an embodiment of the present invention provides a method for predicting rigidity and bearing capacity of a plate node under bolt loosening, the method comprising: obtaining structural information, material mechanics data and bolting related data of the plate node, and constructing a plate node finite element model integrating stress response, geometric form change and contact interface action of the material; Configuring bolt loosening test equipment, setting different test conditions to start a test, recording test data of bolt pre-tightening force changing along with time, analyzing curve characteristics of the bolt pre-tightening force changing along with time based on the test data of the bolt pre-tightening force changing along with time, extracting parameter data related to an attenuation process, and constructing a time-varying attenuation model of the bolt pre-tightening force; Modifying a contact interface unit of the plate node finite element model, embedding pre-tightening force attenuation data output by the bolt pre-tightening force time-varying attenuation model into the contact interface unit of the plate node finite element model, establishing a parameter transmission channel between the plate node finite element model and the bolt pre-tightening force time-varying attenuation model, and completing coupling treatment to obtain a bolt loose coupling finite element model; Extracting key parameters affecting the rigidity and the bearing capacity of the plate-type node, generating a plurality of groups of parameter combination schemes, sequentially inputting a bolt relaxation coupling finite element model for numerical simulation, and recording corresponding rigidity change data and bearing capacity data of the plate-type node to form a parameter association data set; And (3) sorting all data in the parameter association data set, selecting an adaptive regression analysis method, and constructing a mathematical expression based on the association relation between the data, wherein the mathematical expression is based on specific time point data and bolt pretightening force attenuation data, and outputting corresponding plate node rotation stiffness data and bearing capacity data. In still another aspect, an embodiment of the present invention further provides a system for predicting rigidity and bearing capacity of a plate node under bolt loosening, including: the system comprises a processor, a machine-readable storage medium for storing machine-executable instructions of the processor, wherein the processor is configured to execute the method for predicting the rigidity and bearing capacity of the bolt-loosening lower plate type node through executing the machine-executable instructions. In yet another aspect, embodiments of the present invention further provide a computer program product including machine-executabl