17 results about "Nonlinear finite element model" patented technology

The invention discloses a concrete structure seismic damage assessment method and system based on multi-source data feature fusion, belongs to the technical field of civil engineering structure seismic damage assessment, and aims to solve the problem that single-source data cannot accurately reflect the seismic damage state of a concrete structure. Extracting geometric deformation characteristics by using a laser radar, and extracting overall rigidity characteristics by using an acceleration sensor; holographic damage feature vectors are constructed through a weighted fusion algorithm, constitutive parameters of the nonlinear finite element model are automatically corrected through the vectors, and finally the residual bearing capacity of the structure is obtained through numerical simulation calculation. Objective and rapid recognition of post-earthquake structural damage is realized, and a specific structural safety reserve quantitative index can be output.

The invention relates to an icing power transmission line galloping simulation method and simulation system based on a composite time integral. The method comprises the following steps: S1, establishing a nonlinear finite element model of an icing power transmission line; s2, carrying out time domain solution by adopting a composite time integration algorithm; calculating the solution of the moment in two sub-steps according to the solution of the moment, namely from the first sub-step to the second sub-step; the first sub-step adopts a trapezoidal rule for integration, and the second sub-step adopts a three-point backward difference format based on information of three moments; s3, coupling and solving a nonlinear aerodynamic load related to the speed; s4, obtaining the galloping response of the power transmission line; the problems that in a transmission line galloping simulation technology based on a traditional Newmark method, contradiction between calculation efficiency and numerical precision exists in the strong nonlinear coupling problem, accurate tracking of low-frequency galloping and efficient suppression of high-frequency noise are difficult to achieve at the same time under the large time step length, simulation calculation efficiency is low, and convergence is poor are solved.

The invention provides a nonlinear finite element discrimination method for a critical stable section of an underground cavern, and the method comprises the steps: determining a rock mass strain softening parameter according to a rock mass mechanical test in actual engineering; performing secondary development on a rock mass constitutive model based on the rock mass strain softening parameters; based on the rock mass constitutive model after secondary development, a nonlinear finite element initial model for solving the critical stable section of the underground cavern is constructed; the nonlinear finite element model is solved, and the overall tangent rigidity of the model in the calculation time step is obtained; based on the overall tangent stiffness, calculating to obtain a minimum characteristic value of an overall tangent stiffness matrix; and based on the minimum characteristic value, distinguishing the critical stable section of the underground cavern. The method directly and quantitatively reflects the essential characteristics of rigidity loss and bearing capacity reduction of the whole cavern structure system after a complex nonlinear deformation path including strain softening is considered, so that the critical instability moment and the potential instability section are accurately captured.

The invention discloses a soft soil stratum shield tunnel tough structure design method which specifically comprises the following steps: A, establishing a refined numerical model containing a whole-ring shield tunnel, and calculating a reasonable thickness-diameter ratio of the shield tunnel adapted to soft soil stratum environment change characteristics; b, a three-dimensional refined nonlinear finite element model of the shield tunnel joint is established, and shield tunnel joint optimization construction under the full-life-cycle service condition is carried out; c, providing a joint rigidity internal force-deformation cross iteration method, calculating shield bearing deformation, and analyzing shield tunnel deformation resistance under different design conditions; and D, carrying out a field experiment, proposing a double-control principle of construction performance and waterproof performance of the rubber sealing gasket, and carrying out optimal design of the tunnel waterproof sealing gasket. Compared with a conventional staggered joint assembly shield tunnel, the tough main body structure of the staggered joint assembly shield tunnel has the advantages that the allowable limit convergence deformation and the unloading amount of the tunnel under the lateral unloading damage working condition are improved by 37% and 141% respectively.

The invention relates to the technical field of structural engineering safety monitoring, in particular to a fire resistance real-time evaluation system and method based on a steel structure, and the method comprises the steps: collecting the surface radiation energy of the steel structure through a distributed thermal infrared imager array, and constructing a millimeter-level precision three-dimensional temperature field distribution diagram in combination with an environment temperature compensation algorithm; inputting the temperature field into the phase change correction model, and dynamically calculating a yield strength attenuation coefficient and an elastic modulus reduction coefficient; constructing a thermal-mechanical coupling nonlinear finite element model based on the degradation parameters, iteratively solving the displacement and stress response of the structure under the fire load action by adopting an arc length method, and extracting a buckling critical load spectrum; and according to the ratio of the real-time fire load to the critical load, a fire-resistant safety level signal is generated, and a graded early warning instruction is triggered. According to the invention, thermal-force response whole-process monitoring and intelligent early warning of the steel structure in a fire disaster can be realized, and the system has high spatial resolution, high physical coupling and multi-level response capability.

The invention relates to the technical field of data processing, in particular to an elastic frame optimization design method and system based on the finite element theory, and the method comprises the steps: constructing a nonlinear finite element model of an elastic frame, and for each node, determining the sealing reliability of the node based on the normal contact stress value, fluid pressure value and displacement vector of the node; for each unit, determining a fluid permeation trend factor of the unit based on the sealing reliability of the nodes in the unit, remodeling a material relative density iterative updating formula of the optimization criterion method by using the fluid permeation trend factor, updating the material relative density of each unit, generating an optimal topological configuration, and carrying out the optimal topological configuration; therefore, the optimal design of the elastic frame is completed. According to the method, the problem of high-pressure leakage caused by neglecting microscopic sealing in traditional topological optimization is solved, and synchronous optimization of the structural rigidity and the sealing performance under the ultrahigh-pressure working condition is achieved.

The invention specifically discloses an optimal selection method for a seismic oscillation intensity index of an underground diaphragm wall-subway station system, and relates to the technical field of underground structure anti-seismic performance evaluation. The method comprises the following steps: constructing a diaphragm wall-subway station two-dimensional nonlinear finite element model; obtaining an engineering demand parameter EDP through nonlinear time-history analysis, calculating a candidate seismic oscillation intensity index set IMs, forming an original database of IMs and EDP, and dividing a training set and a test set; generating an optimal candidate IM combination on the training set by using a filtering method, an embedding method and a wrapping method; building a multi-model verification platform, and evaluating the generalization performance of each combination based on a model-independent evaluation standard; comprehensively analyzing and determining the combination of the optimal scalar IM and the optimal vector IM; and verifying the whole optimization method through vulnerability analysis. According to the method, the limitation of a traditional method is broken through, the accuracy of earthquake resistance evaluation is improved, the adaptability of the method is defined, and reliable technical support is provided for earthquake disaster prediction and vulnerability analysis.

The invention discloses a rapid evaluation method for traffic safety of a railway bridge after an earthquake based on a genetic algorithm. The method comprises the following steps: creating a track-bridge nonlinear finite element model; simulating high-frequency acceleration seismic oscillation, simulating low-frequency velocity pulses, converting high-frequency acceleration into high-frequency velocity, and performing superposition of high-frequency and low-frequency components to generate a seismic oscillation sample; performing bridge response calculation on the track-bridge nonlinear finite element models under different earthquake magnitudes, and extracting post-earthquake track residual deformation; taking post-earthquake track residual deformation as compensation of an initial irregularity spectrum, and adding the initial irregularity spectrum into a trigonometric series superposition method to obtain a post-earthquake track irregularity spectrum; calculating to obtain a post-earthquake driving condition, and storing the earthquake magnitude and the corresponding driving state; and building a post-earthquake traffic safety rapid evaluation platform based on a genetic algorithm, and evaluating whether the railway bridge can safely run after the earthquake. The technical effect of the invention is that technical support is provided for rapidly evaluating the traffic safety of the railway bridge after the earthquake and stopping inspection.

This invention relates to the field of disaster prevention and mitigation technology for marine engineering structures, and discloses a method for plotting vulnerability curves of guide seawall structures based on random load combinations. The method includes: constructing a nonlinear finite element model of a deep-water guide seawall; introducing a two-dimensional phase coupling vector to generate random dynamic load samples containing temporal coupling characteristics of earthquakes and waves; inputting the samples into the model, tracking the structural frequency drift in real time and considering pore flow abrupt change damping, and calculating the multidimensional dynamic response of the structure; constructing a multidimensional dynamic limit state surface that shrinks with cumulative plastic damage, and determining the failure state based on the relative relationship between the dynamic response and the state surface; estimating the failure probability using extreme value statistics theory, and establishing a probabilistic demand model containing cross-coupling terms of earthquake and wave intensity; and plotting a vulnerability surface describing the change of the failure probability with bivariate strength indices based on this model. This invention can accurately assess the dynamic reliability of deep-water guide seawalls under the coupling effects of multiple disasters.

The invention relates to a nonlinear structure reduced-order model construction method based on sparse recognition and a mixed mode, belongs to the technical field of structural dynamics analysis and aeroelastic mechanics analysis, and solves the problem that complex motion caused by geometric nonlinearity under large deformation cannot be accurately described in the prior art. Comprising the following steps: S1, establishing a nonlinear finite element model of a target large flexible wing to obtain a training data set; s2, solving a mixed modal basis based on the displacement residual error and SVD (Singular Value Decomposition); s3, establishing a nonlinear stiffness coefficient solving problem model, introducing LASSO regression to establish an LASSO regression optimization objective function, and solving to obtain a sparse nonlinear stiffness coefficient; s4, based on the sparse nonlinear stiffness coefficient and the structural kinetic equation, establishing a nonlinear structure reduced-order model; and S5, applying the nonlinear structure reduced-order model to statics response solution and dynamics response solution of the large flexible wing to obtain statics response and dynamics response results.

The application relates to the technical field of data processing, in particular to an elastic frame optimization design method and system based on a finite element theory, which comprises the following steps: constructing a nonlinear finite element model of an elastic frame; determining the sealing reliability of each node based on the normal contact stress value, the fluid pressure value and the displacement vector of the node; determining the fluid permeation trend factor of each unit based on the sealing reliability of the nodes in the unit; remodeling the material relative density iterative update formula of the optimization criterion method by using the fluid permeation trend factor, updating the material relative density of each unit, and generating an optimal topology configuration, so as to complete the optimization design of the elastic frame. The method solves the high-pressure leakage problem caused by the ignorance of micro-sealing in traditional topology optimization, and realizes the synchronous optimization of the structural stiffness and the sealing performance under the super-high pressure working condition.

This invention provides a nonlinear finite element method for determining the critical stability section of an underground cavern. Based on rock mechanics tests in actual engineering, the rock mass strain softening parameters are determined. A secondary development of the rock mass constitutive model is performed based on these parameters. An initial nonlinear finite element model for solving the critical stability section of the underground cavern is constructed based on the secondary developed rock mass constitutive model. The nonlinear finite element model is solved to obtain the overall tangential stiffness of the model at the calculation step. Based on the overall tangential stiffness, the minimum eigenvalue of the overall tangential stiffness matrix is ​​calculated. Based on the minimum eigenvalue, the critical stability section of the underground cavern is determined. This invention directly and quantitatively reflects the essential characteristics of stiffness loss and bearing capacity reduction in the entire cavern structure system after considering complex nonlinear deformation paths, including strain softening, thereby accurately capturing the critical instability moment and potential instability sections.

The application discloses a finite element model correction and safety state evaluation method suitable for complex engineering structures and belongs to the technical field of civil engineering structure safety state evaluation, and comprises the following steps: establishing an initial nonlinear finite element model and obtaining multi-source response data under strong load; performing global parameter sensitivity analysis on all physical parameters and screening out key correction parameters; setting initial system parameters of a UKF algorithm and dividing time windows; sequentially performing single UKF iteration in each time window, recursively updating parameters between windows, and stopping until a convergence condition is met; constructing a mapping relationship between the key correction parameters and structure failure probability by using a Kriging model, and completing proxy model training; and in online evaluation, updating parameters by using an improved UKF algorithm, inputting the updated parameters into the Kriging model, and obtaining the structure failure probability. The application realizes rapid updating of high-dimensional parameters of complex engineering structures and real-time evaluation of safety states by using the above method.

The application relates to a simplified analysis method for a complex independent temporary support system, which comprises the following steps: 1, dividing the demarcation point of the temporary structure and the whole structure; 2, establishing a finite element model of the whole structure; 3, establishing a fine nonlinear finite element model of the complex independent temporary support system; 4, performing nonlinear static analysis on the fine nonlinear finite element model of the complex independent temporary support system to obtain a load displacement curve of the temporary structure; 5, establishing a simplified finite element model of the complex independent temporary support system; 6, performing nonlinear static analysis on the simplified finite element model of the complex independent temporary support system to obtain a simplified load displacement curve of the temporary structure; 7, adjusting the material nonlinearity and the geometric nonlinearity model parameters so that the simplified load displacement curve of the temporary structure approximates to the load displacement curve of the temporary structure; and 8, adding the simplified load displacement curve of the temporary structure meeting the approximation requirement to the finite element model of the whole structure to perform whole structure analysis and calculation.

This invention relates to the field of industrialized construction of steel structures and computer-aided engineering simulation technology, specifically disclosing a steel structure simulation assembly system based on virtual simulation technology. This invention constructs a steel structure model and assembly constraint relationship set through parametric modeling. For high-strength bolt nodes, it constructs a nonlinear finite element model of threaded pair contact friction to solve the preload distribution field. For welded nodes, it constructs a thermo-elastoplastic moving heat source finite element model to solve the residual stress evolution field. These two fields are used as driving loads to recursively calculate the cumulative assembly error, and iterative solutions are triggered synchronously when design parameters change. This solves the technical problems of existing technologies, which struggle to accurately simulate preload distribution, residual stress evolution, and assembly error accumulation, and cannot respond in real time to design parameter changes to achieve collaborative optimization. This improves the accuracy and collaborative optimization capabilities of steel structure assembly simulation.

This invention discloses a method and apparatus for simulation prediction and stability analysis of cracks in spillway dams, relating to the field of hydraulic engineering, for comprehensive analysis of crack formation and stability prediction. The invention establishes a nonlinear finite element model of downstream facade cracks in the spillway dam section, applies loads such as self-weight, temperature, water pressure, sand pressure, uplift pressure, and valve thrust to the model, and then performs simulation calculations of the entire process of spillway dam construction, impoundment, and operation. Next, it inverts the crack initiation and propagation process of the downstream facade cracks in the spillway dam section, performs corresponding repair treatments on the cracks, and evaluates the state of the cracks after treatment through simulation and analyzes the propagation stability of the cracks. This invention more comprehensively considers various influencing factors, provides more accurate crack formation analysis, and has advantages such as high efficiency, accuracy, high stability, strong operability, and low detection cost.

The application discloses a kind of concrete structure earthquake damage assessment method and system based on multi-source data feature fusion, belong to civil engineering structure earthquake damage assessment technical field, for the problem that single source data cannot accurately reflect concrete structure earthquake damage state, the present application extracts apparent damage features using computer vision, extracts geometric deformation features using laser radar, extracts overall stiffness features using acceleration sensor;By weighted fusion algorithm to construct holographic damage feature vector, and using the vector to automatically correct the constitutive parameters of nonlinear finite element model, finally the residual bearing capacity of the structure is obtained by numerical simulation calculation. It realizes the objective, rapid identification of post-earthquake structure damage, and can output specific structure safety reserve quantitative index.