247 results about "Strain rate" patented technology

The invention discloses an intelligent monitoring system for deformation and stress of a deep foundation pit supporting structure, relates to the technical field of deep foundation pit supporting monitoring, and is used for solving the problem of poor early warning of the deformation risk of the supporting structure. According to the method, high-density acquisition of inclination angle, deformation and stress data of a key area of a deep foundation pit supporting structure is realized by constructing a sensitivity-driven measuring point layout mechanism; the method comprises the following steps: constructing an inversion model based on stress and strain rates, obtaining a structural equivalent modulus, extracting a change rate of the structural equivalent modulus, judging a rigidity evolution trend, further constructing a modulus change rate space field, setting a region threshold by combining a disturbance sensitivity factor, realizing abnormal region identification and spatial positioning, and extracting structural response behavior information on the basis. And driving a system to trigger a grading response strategy according to an analysis result of the structure response behavior information, thereby realizing intelligent early warning of local deformation and stress instability of the deep foundation pit supporting structure.

The invention belongs to the technical field of radial forging machine control, and particularly relates to a high-precision radial forging machine control system and a control method thereof.The method comprises the steps that a technological parameter database is established, dynamic parameters in the forging process are synchronously collected through a multi-source heterogeneous sensor, and workpiece surface temperature field distribution is obtained through an infrared thermal imager; measuring radial deformation through a laser displacement sensor group, and capturing internal defect characteristics of the material by using an acoustic emission sensor; the optimal forging frequency is calculated according to real-time material rheological characteristics, and a model predictive control algorithm is adopted to generate hammerhead motion trail correction; dynamic compensation control is implemented, and the back pressure of the hydraulic system is adjusted through strain rate feedback; and closed-loop quality evaluation is executed, online metallographic analysis is carried out in the forging intermittent period, process parameters are reversely corrected according to the grain size detection result, the fatigue life of the workpiece is predicted based on a digital twin model, and the effects that the whole forging process is dynamically controlled in real time, errors and deviation are effectively eliminated, and the forging precision is improved are achieved.

The invention relates to a grid steel structure node failure diffusion prediction method, which comprises the following steps of: forming a failure inducement and evolution path model according to a connection form of a bolt-sphere node and a welding node, a stress transfer path, node local yield and fatigue accumulation factors; a diffusion logic of node failure-force flow redistribution-adjacent node stress concentration-chain reaction is constructed; nodes are regarded as middle points of the graph, rod pieces are regarded as edges, and propagation weights between the nodes are defined; the weight parameters are dynamically assigned based on material attributes, node connection types, spatial geometric positions and historical stress states; multi-source monitoring sensors including strain gauges, displacement meters, thermometers and accelerometers are arranged at key nodes of the grid structure, so that node states are sensed; in combination with real-time monitoring data, extracting strain rate change, vibration characteristics, frequency drift and residual deformation key characteristics of each node; a node health state feature vector set is constructed by using time sequence analysis, and the gradual degradation trend of nodes is reflected.

The invention relates to the field of tunnel engineering geology and support design, and discloses a weak surrounding rock tunnel deformation risk discrimination method based on shear expansion-shear constitutive, which comprises the following steps: constructing a nonlinear coupling model between a shear expansion angle and shear stress, normal stress and joint parameters, and obtaining the shear expansion angle; establishing a volumetric strain rate discrimination formula; inverting an initial crustal stress tensor field; reconstructing an irregular tunnel boundary; constructing a risk level discrimination model, and outputting a risk level; supporting schemes such as supporting rigidity, anchor rod parameters and spraying layer thickness are matched according to the risk grades; establishing a model to predict a risk trend; a support adjustment suggestion is generated; collecting monitoring data to dynamically correct model parameters; and all the modules are integrated in a deployment system. According to the method, the coupling relation between the shear expansion angle and the shear strength is introduced, the coupling type constitutive discrimination model is established, the risk grading system and the support correction strategy associated with the support response are constructed, and active early warning of the high-risk section and dynamic adjustment of the support rigidity are achieved.

The invention belongs to the technical field of bridge safety evaluation, and particularly discloses a method and a system for evaluating local scouring of a bridge pile foundation based on a flow velocity strain rate. A calculation model of a local scouring pit form and a maximum scouring depth of a river-sea crossing bridge pile foundation is established, and a Reynolds stress tensor is converted into a flow velocity strain rate scalar; the method comprises the following steps: providing an erosion-deposition model, analyzing an erosion-deposition rate, establishing a scouring depth relationship, utilizing a sediment transportation model of grid unit storage parameters, simulating dynamic response of a water-sediment mixture, and triggering sediment sliding and updating a riverbed terrain when the dip angle of a scouring pit is at a supercritical slope by virtue of a slump model. All the models cooperate to achieve efficient simulation of local scouring of the pile foundation. According to the method, the form evolution and the maximum scouring depth of the local scouring pit of the single pile and the pile group can be efficiently and accurately calculated, and support is provided for bridge pile foundation design and anti-scouring structure optimization.

The invention discloses a scanning electrochemical microscope in-situ stress corrosion testing device and method, and belongs to the technical field of material stress corrosion testing, and the device comprises a base, a power transmission module, a clamping module, a corrosion module, a signal acquisition module and a scanning electrochemical microscope module. Slow strain rate stretching of a sample is achieved through a servo motor, a planetary gear speed reducer and a transmission mechanism, the clamping module is integrated with a force sensor to monitor loads in real time, the corrosion module provides a temperature-controllable corrosion environment, and the scanning electrochemical microscope module achieves electrochemical scanning of the surface of the sample. The device can synchronously obtain a load-deformation curve, corrosion morphology and microcell electrochemical information under stress-corrosion-temperature multi-field coupling, and provides an effective technical means for deeply researching a stress corrosion mechanism of a material. The method comprises the steps of sample installation, corrosion solution preparation, electrode arrangement, tensile test, electrochemical scanning and the like, and has the advantages of simplicity and convenience in operation, comprehensive data, high precision and the like.

The invention provides a TA15 titanium alloy frame beam forging method and a TA15 titanium alloy frame beam, and relates to the field of aircraft part forging. The method comprises the steps that a TA15 titanium alloy bar is obtained; the TA15 titanium alloy bar is subjected to free forging and pre-forming to form an intermediate blank; the intermediate billet is forged in the alpha + beta two-phase region temperature interval according to a preset strain rate interval, and a TA15 titanium alloy frame beam forged piece is obtained; and the strain rate interval is 0.01 s <-1 > to 0.10 s <-1 >. The method is suitable for the forging process of TA15 titanium alloy frame beams and is used for guaranteeing the structure and performance of TA15 titanium alloy forgings.

The invention provides an impact deformation feature extraction method based on high-speed camera shooting and image processing, and the method comprises the steps: collecting the transient deformation data of the edge package of a remote controller housing under impact through high-speed camera shooting, recording the change speed of a strain rate, obtaining the material characteristics, the size of a package structure, and the geometric discontinuous features of an opening and closing part, generating continuous frame sequence images; performing strain field data quantification processing on the third visualization result, extracting strain field characteristic data, and judging influence weights of stress wave reflection on strain fields of different functional areas of the shell in combination with a falling height and an impact angle of the remote controller; and improving edge packaging design parameters according to the deformation buffer effect and discontinuous quantitative indexes at the opening and closing positions, verifying the improvement amplitude of the deformation buffer effect, and obtaining strain field distribution data of the optimized shell.

According to the construction method of the PE failure constitutive model under the synergistic effect of the temperature and the mechanical load, the engineering stress-strain data of the PE pipe at the corresponding temperature and the corresponding strain rate are obtained based on the tensile property tests of the PE pipe at the different temperatures and the different strain rates, and the true stress-strain data of the PE pipe are further obtained. Aiming at the condition that the existing polyethylene material failure criterion does not consider the service temperature, a hyperbolic constitutive model proposed by Suleiman is improved, and a polyethylene failure constitutive model based on the environment temperature-external load synergistic effect is deduced. The method can be used for predicting the mechanical properties of polyethylene at different temperatures and different strain rates, and the test and experiment cost is effectively reduced; in engineering practice, the method has important guiding significance for safe use of polyethylene buried pipelines in different service environments.

The invention relates to the technical field of mechanical property testing of metal materials, and provides an unsteady-state in-situ high-temperature forming property testing device and method. A punch constant strain rate loading model is arranged in the device, the punch moving speed is adjusted in real time to realize punch constant strain rate loading, and the rheological behavior of a constant strain rate sensitive material in a complex stress state is accurately tested; a rapid cooling system is arranged, so that accurate simulation of complex unsteady-state forming processes such as actual hot stamping and warm forming is realized, and the unsteady-state in-situ high-temperature forming performance of the material is obtained; in combination with a DIC dynamic strain measurement technology, a strain field and deformation force are collected in real time in a plate high-temperature plane stress bulging test, and local necking strain and main strain and secondary strain change paths are determined. According to the method, the reliability of researching macroscopic rheological behaviors such as strain field distribution, flow behavior, hardening mechanism, forming limit and fracture limit of the plate in a complex stress state can be remarkably improved.

The invention discloses a uniaxial compression performance test analysis method of HFGPC under quasi-static and seismic strain rates, relates to the technical field of concrete material performance testing, and is characterized in that test data is collected and analyzed while a test piece is manufactured to carry out an experiment. The uniaxial compression performance of the HFGPC under the quasi-static state and the seismic strain rate can be comprehensively and systematically researched, including the aspects of failure form, stress-strain curve, mechanical property parameters, deformation parameters and the like, and abundant data support is provided for deeply knowing the mechanical behavior of the HFGPC. The test results are analyzed in detail and deeply, including strain rate effect analysis and mechanism analysis, so that the performance change rules and internal reasons of the HFGPC under different strain rates can be disclosed, a scientific theoretical basis is provided for the application of the HFGPC in practical engineering, and the engineering design can be optimized and the safety and durability of the structure can be improved.

The invention provides a model-based dense exhaust film hole creep life evaluation method. The evaluation method comprises the following steps: determining whether a model meets a nickel-based single crystal dense exhaust film hole turbine blade model or not; if yes, deriving a creep constitutive equation of the nickel-based single crystal alloy based on a crystal plasticity theory, and establishing a relational expression among creep damage, creep time, stress and strain rate; deriving a creep life prediction model based on continuous damage mechanics, and establishing a creep life prediction model between creep damage and creep life of the equivalent model; according to the principle that the creep deformations under the same load and temperature and the same creep time are the same, a neural network method is adopted to obtain creep equivalent parameters; simplifying the blade model with the dense gas film holes into an equivalent model containing a small number of gas film holes; and substituting the creep equivalent parameters of the equivalent model into the equivalent model for calculation to obtain the creep damage of the equivalent model, and evaluating the creep life according to the established creep life prediction model.

The invention belongs to the field of structural engineering, and particularly relates to a concrete compressive strength calculation method considering a strain rate effect and a size effect. The concrete compressive strength formula considering the size effect and the strain rate effect at the same time is deduced from the size effect formula and the strain rate effect formula of the concrete compressive strength. The formula comprises a constant term, a strain rate effect term, a size effect term and an interaction term. The constant item reflects the static strength of the concrete cubic test piece, the strain rate effect item reflects the strength improvement caused by strain rate increase, the size effect item reflects the strength reduction effect caused by test piece size increase, and the interaction item reflects the strain rate effect increase caused by the size increase and the size effect reduction caused by the strain rate increase. And finally, fitting all test data by adopting a multiple regression method to obtain various parameters of the concrete compressive strength. The formula fitting effect is good, the regression residual error is small, and the adaptability of the calculation method is verified.

The invention relates to the technical field of material mechanical property testing, and provides an ultralow-temperature slow strain mechanical tensile test platform which comprises a vacuum Dewar unit, a liquid helium temperature control unit, a slow strain tensile unit, a measuring unit and a control unit, the vacuum Dewar unit comprises a vacuum Dewar body and is used for providing a closed low-temperature test environment; the liquid helium temperature control unit comprises a direct injection module and a recovery module, the direct injection module is used for directly injecting liquid helium to the gauge length section of the sample for cooling, and the recovery module is used for recovering and recycling unevaporated liquid helium; the slow strain stretching unit is used for stretching a sample arranged in the vacuum Dewar body at a low strain rate; the measuring unit is arranged in the vacuum Dewar body and is used for monitoring the temperature, the force value and the strain data of the sample in real time. Liquid helium is used as a cold source, the liquid helium is directly aligned to the gauge length section of the sample through the direct injection module, and compared with a traditional liquid helium steam natural convection heat exchange mode, the heat exchange coefficient is increased, and automatic precise temperature control is achieved.

The invention relates to the technical field of layered metal, and discloses a metal layered material self-adaptive welding parameter regulation and control method and system.The method comprises the steps that the temperature gradient response amplitude value and the interlayer thermal deformation quantity of an interlayer bonding area of a welding pool are extracted; the equivalent difference value of the expansion coefficients of the adjacent material layers under the same welding heat is obtained, the interface strain rate of the adjacent material layers is corrected based on the equivalent difference value, and the thermal deformation relative offset of the metal layered material is obtained; inverting a diffusion path of the characteristic elements in the interlayer bonding area to obtain an alloying process index of the metal layered material; when the alloying process index is lower than a critical value, the arc energy density in the welding pool is reduced, and the swing frequency of a welding gun is increased; dynamically compensating welding thermal parameters of the welding pool according to the change rate of the interlayer thermal deformation quantity in a layered material thickness abrupt change area; according to the method, the welding quality of self-adaptive welding of the metal layered material can be improved.

The invention relates to the technical field of die forming, in particular to a variable-temperature deep drawing-rapid air expansion composite forming method for a thick titanium alloy plate. The method comprises the steps that a model of a stamping die of the end socket is established, and the thickness of a to-be-stamped plate is set; limiting conditions in the stamping process are set, and a variable-temperature deep drawing model is obtained; establishing a Backoften constitutive equation, and determining strain rate sensitive indexes and strength coefficients at different temperatures according to the material strength at different temperatures; performing a finite element simulation process according to the strain rate sensitive index and the strength coefficient to obtain a superplastic inflatable model; according to the variable-temperature drawing model and the superplastic air expansion model, a variable-temperature drawing-rapid air expansion model is established; representing the simulation performance of the variable-temperature drawing-rapid air expansion model, and analyzing a drawing result and an air expansion result; and determining a test reference according to an analysis result, and carrying out a variable-temperature drawing-rapid inflation composite forming test. According to the scheme, excessive attempts of experiments can be reduced.

The invention discloses a material stress-strain constitutive relation modeling method and device, a program product and a medium, and relates to the technical field of metal material constitutive models. Uniaxial tensile experiment data of a metal material under the conditions of different temperatures and different strain rates is obtained and preprocessed, and a training data set reflecting mechanical behaviors of the material under the wide-range working condition can be constructed; constructing an initial neural network model comprising a main body network structure layer, a neuron unit, a connection parameter and a training mechanism based on the training data set, and performing iterative optimization on a hyper-parameter by adopting a Bayesian optimization algorithm to obtain a target neural network model; the nonlinear stress-strain relationship of the material under the conditions of different temperatures and strain rates can be accurately captured; the target neural network model is further converted into a user-defined material subprogram of the finite element analysis platform, and the subprogram can output a predicted material stress value according to the input strain, strain rate and temperature, so that seamless joint with a universal finite element analysis platform is realized, and the prediction precision of simulation is improved.

The invention relates to a saturated granular material liquefaction deformation calculation method based on a state evolution model, which comprises the following steps: establishing a saturated granular material liquefaction state evolution model, and setting a state parameter representing system fluidity in the state evolution model as a weighted average value of a historical strain rate function and an excess pore water pressure change rate function; analyzing and determining a shear strain time travel curve, a stress strain curve and a state parameter evolution curve according to the state evolution model; and carrying out saturation granular material liquefaction discrimination according to the state parameters. According to the saturated granular material liquefaction deformation calculation method based on the state evolution model, the Davidenkov model and the unified softening model are introduced to describe shear modulus softening, the liquefaction deformation calculation method is provided, and finally the accuracy of the calculation method is verified through a series of experimental data and simulation data.

The invention relates to a method for evaluating the hydrogen-induced delayed fracture risk of high-strength steel. The method comprises the following steps: stretching a notch sample to be measured at a strain rate in a range of 3.0 * 10 <-6 >-6.0 * 10 <-5 > s <-1 > until fracture so as to obtain a fracture stress sigma H, and stretching a reference notch sample at a strain rate in a range of 6.0 * 10 <-2 >-10.0 s <-1 > until fracture so as to obtain a reference fracture stress sigma 0; and evaluating the hydrogen-induced delayed fracture risk by using a hydrogen embrittlement risk index HERI = (sigma0-sigmaH) / sigma0 * 100%. According to the evaluation method, the influence of hydrogen in the high-strength steel on the performance can be accurately reflected, the test process is simplified, and rapid inspection on a production site is facilitated. The invention also relates to a method for determining the available dew point range of an austenitizing process for producing a hot-stamped product with an aluminum-silicon coating, which is resistant to hydrogen-induced delayed fracture.

The invention discloses a steel rail hidden damage crack initiation simulation prediction method considering three-dimensional geometric irregularity of a rail surface. The method comprises the following steps: step 1, acquiring wheel-rail dynamic response and strain rate space-time distribution characteristics; 2, calculating the local elastic-plastic contact stress of the wheel rail; 3, establishing a circulating rolling three-dimensional local finite element model, and solving a steel rail plastic stress-strain solution; and 4, solving the steel rail hidden damage crack initiation angle and the crack initiation life by adopting a plastic stress-strain solution. According to the steel rail hidden damage crack initiation simulation prediction method considering the three-dimensional geometric irregularity of the rail surface, the three-dimensional geometric irregularity of the surface of the steel rail is considered, the application range of traditional dynamics is expanded, and initiation and development of steel rail hidden damage cracks can be predicted more accurately; and a guidance basis is provided for formulating a reasonable grinding period and grinding depth on site and selecting a material of a newly-replaced steel rail, and the method has a wide application prospect.

The invention provides a hot working parameter design and optimal selection method of a titanium alloy blade capable of preventing instability and keeping forming. The machinability of the material can be reflected more comprehensively, and the instability phenomenon in the machining process is avoided. The method is characterized by comprising the following steps: step 1, cutting a plurality of cylindrical samples from a titanium alloy material; a Gleeble-3500 thermal compression simulation experiment machine is used for carrying out thermal compression tests on the titanium alloy cylinder sample at different temperatures and strain rates, and true stress strain data under different deformation conditions are obtained; step 2, based on a dynamic material model (DMM) principle, according to the true stress strain data obtained in the step 1, respectively calculating strain rate sensitivity coefficients, power dissipation efficiency and instability coefficients under different true stress strains; 3, constructing power dissipation diagrams and instability diagrams under different true stress strains according to the power dissipation efficiency and the instability coefficient of the material obtained in the step 2, taking the dependent variable as a z axis, and respectively placing the power dissipation diagrams and the instability diagrams under different strains at corresponding positions of the z axis to obtain a three-dimensional power dissipation diagram and a three-dimensional instability diagram; step 4; and 3, superposing the three-dimensional power dissipation diagram and the three-dimensional instability diagram obtained in the step 3 to obtain a three-dimensional instability region trend diagram and a safety region trend diagram, drawing to obtain a three-dimensional hot working diagram for the titanium alloy, and determining the change conditions of the instability region and the power dissipation efficiency of the titanium alloy along with the strain according to the obtained three-dimensional hot working diagram. And therefore, the hot working parameters in the machining process can be always located in the optimal interval.

A forging defect determination system according to the present invention is provided with a forging analysis device (10) and a forging defect determination device (20). A forging analysis device (10) is provided with a first control unit (15) for generating a molded article model in a plurality of molding steps for forging molding. The first control unit (15) is disposed so as to calculate a strain rate on the basis of an analysis grid of the molded object model. The forging defect determination device (20) is provided with a second control unit (25), and is disposed so as to predict, on the basis of the molded article model, the presence or absence of a defect phenomenon when molding the molded article in each molding step of the forging molding. The second control unit (25) is arranged so as to determine the presence or absence of the defect phenomenon on the basis of the strain rate and the surface angle between the surfaces of the adjacent analysis grids.

A forging flaw determination system includes a forging analysis device and a forging flaw determination device. The forging analysis device is configured to generate a forged article model in a plurality of forging processes for forging, and includes a first controller. The first controller is configured to calculate a strain rate based on an analysis mesh for the forged article model. The forging flaw determination device is configured to predict, based on the forged article model, the presence or absence of a flaw phenomenon when a forged article is formed in each forging process for the forging, and includes a second controller. The second controller is configured to determine the presence or absence of the flaw phenomenon based on the strain rate and a face angle between faces of adjacent analysis meshes.

The invention provides a 50Cr5NiMoV alloy forging parameter optimization method, relates to the technical field of metal plastic forming, and quantitatively predicts the cracking risk by combining damage model simulation with blank geometric optimization. The method comprises the following steps: acquiring material mechanical parameters at different temperatures and strain rates through a thermal tensile test, and combining with Normalized Cockcroftamp; a damage model is established according to the damage criterion, the Latham damage criterion and the Zener-Hollomon parameters, and the material fracture risk is quantified. The damage evolution law of the conventional cylindrical blank and the thin kidney-shaped blank is analyzed through finite element simulation, and the blank shape and process parameters are optimized. Results show that the surface damage value of the thin kidney-shaped blank can be remarkably reduced under the conditions that the temperature is 1000-100 DEG C and the upsetting ratio is 2-2.1, the maximum damage value is reduced to 0.30 from 0.46, cracking is effectively inhibited, and therefore a scientific quantitative optimization basis is provided for the upsetting process.

The invention discloses an engine hood determination method and device and electronic equipment. The method comprises the following steps: acquiring a plurality of first target points on a first engine hood model, and performing head collision simulation on the plurality of first target points to obtain strain rate ranges corresponding to the plurality of first target points respectively; determining a plurality of target strain rates according to the strain rate ranges corresponding to the plurality of first target points; material parameters corresponding to the multiple candidate aluminum alloy materials are determined according to the multiple target strain rates; the first engine hood model is adjusted according to the multiple candidate aluminum alloy materials and the corresponding material parameters with the minimization of the head damage index as the target, a target engine hood model is obtained, and the strain rate sensitivity coefficient of the candidate aluminum alloy materials used by an inner plate in the target engine hood model is a negative value. The technical problem that in the prior art, an engine hood is designed based on the material performance of a single strain rate, and the head injury index is high in pedestrian head collision is solved.

The invention discloses a simulation method, device and equipment for a composite material automobile ceiling, and the method comprises the steps: firstly obtaining material samples of different layers, such as a PU foam layer, a non-woven fabric and glass fiber composite material layer, a sponge layer and a fabric layer, on a target automobile ceiling; acquiring at least one material parameter of elastic modulus, Poisson's ratio and stress-strain curve of the material samples at different temperatures and different strain rates; and then an integral sample piece of the target vehicle ceiling is obtained, material testing and simulation benchmarking are carried out on the integral sample piece to verify whether the obtained material parameters are accurate or not, and if yes, simulation modeling is carried out on the target vehicle ceiling by using the material parameters to obtain a simulation modeling result. Therefore, simulation modeling can be carried out on the target vehicle ceiling by layering the composite material, the influence of various materials with different physical attributes on the mechanical property of the ceiling is fully considered, and the simulation modeling precision and the modeling effect are effectively improved.

A safety helmet comprising a housing, a linear impact absorbing material, and a rotary impact absorbing material, the safety helmet constructed from a material designed to provide protection to a wearer under extreme environmental conditions and impacts. In one embodiment, the rotational impact absorbing material is formed from a strain rate sensitive material, where the stiffness of the material increases when subjected to an impact.

Preparation method of nano-spherical B2 phase ultrafine-grained TiAl alloy. The present invention relates to a preparation method of nano-spherical B2 phase ultrafine-grained TiAl alloy. The purpose of the present invention is to solve the problem that a large amount of reticular B2 phase continuously distributes inside and on the boundaries of the lamellae in the existing TiAl alloy containing β-phase stabilizing elements, which will exacerbate the brittle fracture of the alloy as a crack source. The present invention weighs Al, Cr, Re and Ti according to mass percentage, and then uses a vacuum arc melting furnace to prepare an alloy ingot; the alloy ingot is subjected to isothermal axial compression, the strain rate is set to 0.01 s-1, the compression temperature is 1000-1150 °C, and the deformation amount is 80%. After hot compression, the alloy does not occur side cracking and shear fracture, has excellent plastic deformation ability, and at the same time improves the strength and deformation ability of the TiAl alloy. The present invention is applied to the technical field of hot processing preparation of high-temperature light alloys.

The embodiment of the invention discloses a simulation calculation method and device for a thin shell transient jump behavior, a medium and equipment. The method comprises the steps that a thin shell finite element analysis model is established; performing time sequence simulation analysis on the transient jump behavior of the thin shell, and in each time step, calculating a strain change rate characteristic value spectrum, and obtaining a nonlinear strength index and a local stiffness spectrum radius of each unit; when the non-linear criterion index of the unit is greater than a threshold value and the local stiffness spectrum radius is greater than the threshold value, dividing the unit into an explicit domain unit and improving the calculation precision by adopting a sub-step size control technology, otherwise, dividing the unit into an implicit domain unit; a self-adaptive step length technology is adopted, and the calculation efficiency is improved through large-step-length propulsion; calculating an incremental potential energy function, and judging whether the thin shell is about to enter a deformation bifurcation point or not by adopting a stability criterion; and constructing a deformation tentative displacement vector by adopting the fastest descending direction of the potential energy function, and accurately capturing real physical paths of jumping behaviors under various working conditions.

The invention relates to a metal material strain rate effect measurement method based on multiple stress relaxation, which comprises the following steps: carrying out a standard quasi-static stretching or compression test on a material sample at a constant strain rate to obtain a stress-strain curve; analyzing a strain range according to a stress-strain curve, and determining a stress relaxation frequency N to be developed and a corresponding relaxation strain value sequence epsilon i, i = 1... N; a material sample is taken to be subjected to a tensile or compression test at a set strain rate, stress relaxation lasts for relaxation time delta t when the strain sequentially reaches values in each relaxation strain value sequence, and after each stress relaxation, the tensile or compression test is performed according to the set strain rate; obtaining a stress-plastic strain rate curve corresponding to each relaxation strain epsilon i; and obtaining a stress-strain curve corresponding to each strain rate. Stress-strain curves corresponding to different plastic strain rates in a quasi-static range can be obtained through a single sample.