36 results about "Nonlinear finite element model" patented technology

The invention relates to technology field of mechanical engineering and mathematics research, specifically relates to a planning method of asymmetric variable acceleration based on optimal distribution in the time-domain of main frequency energy, and the method includes: solving positioning course of nonlinear finite element model including the free kinematics and parametric motion function, after execution stopping judging the amplitude of the drive end whether or not meets the positioning accuracy, if meet, the amplitude energy time is decayed,if not meet ,it will go on solving; judging the target response time whether or not it is a minimal value,if the time is a minimal value, determining to set the motion parameters as the optimal parameter ,if the time is not a minimal value,calculating the motion parameters of step and gradient and reset motion parameters to be solve. The invention by the above method solves the motion planning question of nonlinear effect and high speed and high acceleration under precision positioning requirements. The precision positioning and position / force smooth handoff in high speed condition can be achieved. It also adapts to motion planning question of performance administration to the traditional solving method.

The invention provides a method and system for predicting the nonlinear wind-induced response of a suspension bridge, and a storage medium. Firstly, the aerodynamic time histories of the girder section under different wind speed and amplitude are numerically simulated by CFD, and then all aerodynamic parameters in the unified nonlinear and unsteady aerodynamic time domain model are identified by nonlinear least square fitting method, and the results are compared with the CFD results. Then the unified aerodynamic model is coupled with the three-dimensional nonlinear finite element model of thebridge to predict the nonlinear wind-induced response of the bridge in the process of the wind speed increasing from zero to the preset limit wind speed. The unified aerodynamic time domain model of the present invention includes static wind, The mathematical expressions of self-exciting force, buffeting force, vertical vortex force and torsional vortex force and their corresponding parameters canbe used to accurately predict the nonlinear wind-induced response of bridges in different wind speed ranges, which provides important reference for the evaluation of wind-resistant performance of suspension bridges during the passage of strong/typhoon.

The invention relates to a human brain deformation simulation method based on multiple GPUs. A total Lagrangian Method, a central difference method and a nonlinear finite element Neo-Hookean model are used for carrying out explicit iterative simulation on brain deformation, the speed of simulation calculation is quickened through parallel algorithm at GPU ends, after the parallel ability is further improved through introducing the multiple GPUs, a breadth first search method is adopted to carry out data clustering on original data and renumber and minimize a data correlation between nodes, an extra data structure is used to enable a one-to-one correspondence relationship to exist between input data in each node and the calculation process, a stream transmission is further used to realize parallelism between calculation and data transmission, and finally, a multi-core calculation architecture mixing CPUs/GPUs is used for accelerating, and precision and speed requirements in human brain deformation simulation are met. Subtlety and spatio-temporal continuity features in human brain deformation are made full use of, and the brain deformation process can be vividly simulated in a virtual environment constructed by a computer.

The invention provides a railway fastener detection method and device, and the method comprises the steps: obtaining a three-dimensional nonlinear finite element model which is composed of all parts in a fastener system, and enabling the fastener system to comprise an elastic strip; Carrying out static analysis on the three-dimensional nonlinear finite element model to obtain analysis data; Performing modal analysis on the three-dimensional nonlinear finite element model according to the analysis data to obtain each order of vibration mode of the elastic strip and an inherent frequency corresponding to each order of vibration mode; Steel rail corrugation data can be obtained on the basis; Analyzing according to the steel rail corrugation data to obtain wheel rail excitation frequency; Andanalyzing whether the elastic strip resonates or not according to the inherent frequency and the wheel track excitation frequency. According to the method, the influence of each component of the fastener system on the inherent frequency of the elastic strip is fully considered, and the original proportion three-dimensional nonlinear finite element model of the fastener system is established. And carrying out online analysis on the wheel track excitation frequency to obtain the inherent frequency of the fastener system in various states, and comparing the inherent frequency with the wheel trackexcitation frequency obtained by actual detection to judge whether the fastener system generates resonance or not.

The invention provides a belting connection structure contact friction nonlinear feature simulation method. The method includes the following steps that S1, a three-dimensional finite element model of a basic section of a belting connection structure containing a single clamping block is established; S2, correction is conducted on the three-dimensional finite element model to obtain the corrected parameters; S3, a two-dimensional finite element model is established according to the corrected parameters; S4, correction is conducted on the two-dimensional finite element model, a final two-dimensional axisymmetric finite element model is obtained, and analog simulation is achieved. According to the method, a two-step model correct method is adopted, the accuracy of the two-dimensional nonlinear finite element model and the physical significance of all parameters of the model are guaranteed, fast and precise estimation of the belting connection structure nonlinear mechanical property is achieved, and the higher computing accuracy and efficiency are achieved. The invention further provides a belting connection structure contact friction nonlinear feature simulation system.

The invention discloses a bridge wind-induced behavior nonlinear characteristic analysis method, a storage medium and a server, and the method comprises the steps: obtaining the parameters of static wind power, self-excitation force, buffeting force and vortex vibration force based on a large-span bridge nonlinear aerodynamic model; generating different wind field data of the bridge site region based on a harmonic synthesis method and an FFT technology; establishing a three-dimensional nonlinear finite element model of the bridge, loading the nonlinear aerodynamic unit and the wind field datato a main beam unit, and performing coupling dynamic calculation to obtain a nonlinear wind-induced behavior of the bridge in a predetermined wind speed interval; and nonlinear dynamic behavior characteristics of various wind-induced vibrations such as bridge vibration and vortex vibration are analyzed by applying displacement response bifurcations, vibration forms and structure damage modes of the main beams. The method is suitable for analyzing the nonlinear wind-induced behavior of the long-span bridge with different main beam section forms and different structural forms, and is beneficialto revealing the wind vibration mechanism of the long-span bridge.

The invention discloses a bridge model updating method and system based on vehicle-bridge coupling acting force correction, a storage medium and equipment, and belongs to the technical field of engineering. The invention aims to solve the problem of low simulation accuracy caused by the absence of a refined updating method for a bridge model at present. According to the invention, the method comprises the steps: acquiring the dynamic response of the bridge structure under the load effect of the heavy-load vehicle through the sensors arranged on the bridge structure; according to the vertical vibration acceleration a<o> and the vertical deflection y<o> of the bridge at the gravity center o of the heavy-loaded vehicle and the speed u<vehicle> of the heavy-loaded vehicle, reconstructing the table surface response of the vibration table, and obtaining the interaction force of the vehicle-bridge coupling model; establishing a nonlinear finite element model of the bridge structure, taking the vehicle-bridge interaction force as external force, taking the dynamic response of the bridge structure as structural response, and finishing the correction of the finite element model of the bridge structure through a nonlinear parameter identification method. The method is mainly used for updating the bridge model.

The embodiment of the invention provides a railway fastener elastic strip breakage splashing risk prediction method and device, and relates to the technical field of traffic safety. The method comprises the following steps: establishing a three-dimensional nonlinear finite element model and setting the three-dimensional nonlinear finite element model in a service state; establishing a coupling space simulation model of the vehicle and the steel rail; according to the coupling space simulation model, dynamic response data between the vehicle and the steel rail under the condition of corrugationof the steel rail are obtained, inputting the dynamic response data as excitation into a three-dimensional nonlinear finite element model; fracture splashing risk data of the elastic strip is obtained. The method has the advantages that the spatter track can be simulated according to the fracture spatter risk data, accordingly, spatter risks of the elastic strips can be predicted according to thefracture spatter risk data of the elastic strips, risk prediction results can be acquired, comprehensive protection measures can be taken for fracture spatter of the elastic strips, and safe runningof trains during running can be guaranteed.

The invention discloses a complex variable differential sensitivity-based nonlinear structure finite element model correction method, which comprises the following steps of firstly, establishing a nonlinear finite element initial analysis model of a structure; secondly, performing complex step perturbation on a to-be-corrected parameter in the structure, and calculating nonlinear dynamic responsesensitivity; thirdly, measuring response data of the structure, and establishing an objective function of nonlinear model correction; and finally, performing least square optimization on the measureddynamic response and the analyzed dynamic response so as to realize nonlinear finite element model correction, so that the structural parameters of the nonlinear finite element analysis model can be corrected, and the calculation precision of the analysis model is improved.

The invention discloses a method for evaluating the pretightening force of a spindle. The method comprises a step of performing load analysis on support bearings of the spindle and solving loads of the spindle bearings, a step of establishing a five-degree-of-freedom nonlinear finite element model of the machine tool spindle bearings and establishing a fitting relationship between the dynamic stiffness of the spindle bearings and the dynamic stiffness of the spindle, a step of calculating the dynamic stiffness of the spindle under different bearing pretightening forces and rotation speeds andestablishing a fitting relationship database between the dynamic stiffness of the spindle and the bearing pretightening forces and the rotation speeds, and a step of measuring the dynamic stiffness ofa spindle front end through a spindle dynamic stiffness measurement experiment and inquiring the obtained dynamic stiffness in the fitting relationship database between the dynamic stiffness of the spindle and the bearing pretightening forces and the rotation speeds to obtain the pretightening force of the machine tool spindle bearings.

A parameter optimization method for pull rod for installing aircraft airborne equipment is disclosed. An aircraft A nonlinear stiffness element is used to simulate the vibration damping device installed in airborne equipments, the nonlinear finite element model of equipment installation pull rod is established, the structural parameters of pull rod are taken as optimization variables, the finite element model is parameterized, a parameterized model with the structural parameters of pull rods as variables is established to determine the constraint conditions and optimization objectives. Given the initial value of the optimization variables, the initial population is generated by using a genetic algorithm program, and the objective function is calculated to generate the next generation of population. step 5 is repeated until the convergence criterion is satisfied, and the final parameters of the pull rods are obtained, and the optimization is finished.

The invention provides a ballastless track self-compacting concrete fatigue damage calculation method, and belongs to the technical field of track traffic. The method comprises the following steps: constructing a self-compacting concrete fatigue constitutive relational expression coupled with damage; embedding the self-compacting concrete fatigue constitutive relation coupled with the damage into the load-ballastless track nonlinear finite element model to construct a damage-finite element coupling model; and analyzing the fatigue damage evolution law of the self-compacting concrete layer of the ballastless track by using the damage-finite element coupling model. According to the method, the coupling relation between fatigue damage and structural stress is revealed through a coupling method, the limitation that the structural stress does not change along with damage accumulation in a traditional decoupling method is overcome, and the influences of train load changes, plate end open joints and initial degradation of self-compacting concrete on the fatigue damage of the ballastless track filling layer are explored; and a certain theoretical support is provided for the long-term service performance research of the ballastless track of the high-speed railway according to the influence rule of fatigue damage accumulation on the bending-tensile stress.

The invention discloses a method for calculating a maximum rotation angle of a pipeline under the action of a fault. The method comprises the following steps: acquiring geometric dimension parameters, material parameters, seismic fault parameters and pipeline laying parameters of the pipeline; establishing a pipeline-fault nonlinear finite element model; selecting influence factors of a pipeline joint corner under the action of a normal fault, determining single-factor test schemes according to the influence factors, and calculating a vertical settlement difference between adjacent pipelines in each single-factor test scheme by using the pipeline-fault nonlinear finite element model to obtain a maximum vertical settlement difference in each single-factor test scheme; calculating the maximum joint corner according to the vertical settlement difference between the adjacent pipelines; and selecting main influence factors, performing dimensionless processing on the main influence factors, and determining a maximum joint corner based on the main influence factors. The prediction error within a given range is less than 10%, and the method has high prediction precision.

The invention discloses a thin film structure reinforcing band layout optimization method and system based on a genetic algorithm, and belongs to the technical field of thin film structures. The layout optimization method comprises the following steps: s1, setting reinforcing band design parameters, and constructing layout optimization parameters; s2, setting genetic algorithm parameters, and initializing a population; s3, decoding the population to obtain a strengthening band layout optimization parameter, establishing a nonlinear finite element model, and solving at the same time; s4, calculating a target function based on a solving result; s5, calculating the fitness by using the target function, and judging whether a stop criterion is met or not; s6, if the stop criterion is not met, performing selection, crossover and mutation operation on the population, and repeating the steps S3 to S5; and s7, if a stop criterion is met, ending the circulation, and outputting an optimal individual. According to the method, the thin film structure reinforcing band layout is optimized through the genetic algorithm, wrinkles of the thin film structure can be effectively avoided, and the performance of the thin film structure is improved.