20 results about "Engineering stress" patented technology

The invention provides a macroscopic finite element simulation analysis method and device for a sealing element considering plastic deformation, and belongs to the field of sealing element design. The method comprises the following steps: acquiring an engineering stress-strain curve of a plastic material in a compression state; converting the engineering stress-strain curve into a real stress-strain curve; determining a yield limit, and taking a strain point corresponding to the yield limit as a demarcation point of elasticity and plastic deformation; an elastic section of a real stress-strain curve is extracted, the elastic modulus is calculated, and the Poisson's ratio is obtained through axial and transverse strain measurement in a uniaxial compression test; a true stress-strain curve plastic section is extracted, and a multi-linear isotropic hardening model is established; constructing a complete elastic-plastic constitutive model covering the elastic deformation area and the plastic deformation area; the stress distribution, the strain response and the contact performance of the plastic sealing element in a compression deformation state are simulated. According to the method and the device provided by the invention, the problem that the result does not conform to the reality due to the fact that only elastic modulus and Poisson's ratio are used in existing sealing element simulation can be solved.

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 discloses a rolling deformation method for improving the mechanical property of a CoCrFeNiMo0.35 high-entropy alloy, through high-temperature severe plastic deformation, the structure of the CoCrFeNiMo0.35 high-entropy alloy is refined, meanwhile, as-cast sample structure defects such as air holes can be eliminated, the alloy structure is densified, and along with the increase of rolling reduction, the mechanical property of the CoCrFeNiMo0.35 high-entropy alloy is improved, so that the mechanical property of the CoCrFeNiMo0.35 high-entropy alloy is improved. And further refining of crystal grains is effectively promoted. This is the first main factor causing improvement of the mechanical property of the alloy. Besides, in the hot rolling deformation process, alloy grains are stretched into a flat shape in the rolling direction, the volume fraction of a sigma phase is increased along with increase of rolling reduction, the sigma phase is a common hard phase in the high-entropy alloy, and therefore improvement of the alloy strength can be promoted, and the strength of the alloy is improved. The room-temperature tensile engineering stress-strain curve of the CoCrFeNiMo0.35 high-entropy alloy corresponding to different rolling reduction amounts is shown in the figure 7. It can be seen that when the rolling reduction is increased from 10% to 50%, the yield strength and the tensile strength of the alloy are both obviously improved.

The invention discloses a modeling method of a TC4 titanium alloy high-precision thermoplastic constitutive model, and belongs to the field of TC4 titanium alloy thin-wall part thermoplastic forming numerical simulation. The method comprises the following steps: firstly, obtaining an engineering stress-strain curve under different loading conditions, converting the engineering stress-strain curve into a real stress-strain curve, establishing a corrected Johnson-Cook constitutive model, and obtaining an initial parameter of the constitutive model; secondly, defining an objective function, a decision variable and a feasible region of an optimization problem by taking the precision of the constitutive model as a reference; thirdly, initial parameters of a sparrow search algorithm are set, an initial population is generated, the positions of a discoverer, a following person and a warning person are updated, and then the population of the next generation is improved; and finally, checking whether the target function value of the next-generation population reaches the target precision or not to obtain parameters of a new constitutive model, and establishing an optimized Johnson-Cook correction constitutive model. According to the constitutive model modeling method, prediction precision, calculation cost and fitting difficulty are considered, and the model precision problem caused by a traditional method can be solved.

The invention discloses a method for identifying parameters of a rubber visco-hyperelastic constitutive model under limited experimental data, and the method comprises the steps: obtaining engineering stress-strain data based on a rubber uniaxial quasi-static compression test carried out on first test rubber; carrying out a rubber dynamic impact test on the second test rubber to obtain dynamic stress-strain data under different strain rates; constructing a viscoelastic constitutive model according to the engineering stress-strain data and the dynamic stress-strain data; and compiling a secondary development subprogram corresponding to the viscoelastic and superelastic constitutive model, and fitting parameters of the viscoelastic and superelastic constitutive model to confirm final fitting parameters of the viscoelastic and superelastic constitutive model. According to the method, the low-efficiency process of traditional manual adjustment is avoided, meanwhile, human intervention is reduced through automatic optimization, human errors are reduced, and the consistency of results is ensured.

The invention belongs to the technical field of material performance testing, and relates to a metal material large-range equivalent stress-strain curve testing method which comprises the following steps: 1, preparing a test piece; preparing the test piece model into a round bar test piece, wherein the middle section of the round bar test piece is provided with an axisymmetric annular notch; 2, testing; a loading device is adopted to load the round bar test piece under displacement control, meanwhile, a high-speed camera is adopted to directly face the round bar test piece to shoot, and the applied load and the change of the notch size are monitored; stopping when the round bar test piece is broken; 3, processing data after the test; sequentially calculating the size of the notch, the strain in the transverse direction of the notch, the real stress in the test process and the engineering stress; 4, correcting real stress; converting the real stress obtained by the notched sample into the equivalent stress of the material; the equivalent stress-strain curve of the material can be obtained by measuring the initial fracture size and the hardening index, and the test cost is lower.

This invention provides a method, apparatus, computer equipment, and medium for predicting the failure of a wheel disc, relating to the field of digital twin technology. The method includes the following steps: conducting a uniaxial quasi-static tensile test on a tensile test specimen to obtain the engineering stress-strain curve of the wheel disc; converting the engineering stress-strain curve into a true stress-strain curve; constructing a wheel disc failure prediction model under deterministic conditions based on the true stress-strain curve; performing sensitivity analysis on the quantified parameters of uncertainty; obtaining sample data under different working conditions through finite element calculation based on key parameters; constructing a maximum strain proxy model for the wheel disc based on the sample data; inputting the key parameters into the maximum strain proxy model to obtain the confidence interval of the wheel disc's rotational speed at the time of failure. This scheme, by constructing a maximum strain proxy model for the wheel disc, achieves high-precision full-domain simulation of the wheel disc's failure process, solving the problems of limited test measurement points and insufficient simulation accuracy.

The invention discloses a material parameter calibration method based on a porosity coupling damage model, and relates to the technical field of vehicles. The method comprises the following steps: acquiring an actual engineering stress-engineering strain curve of a to-be-calibrated material; a finite element model of the to-be-calibrated material is established based on the damage constitutive model, and the damage constitutive model comprises porosity parameters; performing simulation stretching on the finite element model of the to-be-calibrated material to obtain a simulation engineering stress-engineering strain curve of the to-be-calibrated material; adjusting the porosity parameter to enable the overlap ratio of the simulation engineering stress-engineering strain curve and the actual engineering stress-engineering strain curve to reach a preset threshold value, so as to determine the target porosity parameter of the to-be-calibrated material. Therefore, the product development period is effectively shortened, and the test cost is reduced.

The invention discloses a finite element simulation method for analyzing plastic strain transfer of gradient structural steel, and belongs to the technical field of metal material analysis. According to the method, engineering stress-strain curves of different parts of the gradient structural steel are tested by taking performance change reflected by morphology and structure change of the gradient structural steel as a starting point so as to obtain material attributes, a gradient structural finite element simulation model is designed, and a reasonable transition connection mode is set at an interface where the material attributes change; the strain distribution and transmission process of the gradient structural steel is analyzed, a foundation can be provided for clarification of a plastic deformation gradient transmission mechanism of the gradient structural steel, and the mechanical property of the gradient structural steel is further improved on the premise that efficiency is improved and cost is reduced.

The present application relates to the technical field of materials, and relates to a method for automatically solving the elastic modulus of a metal material under dynamic tension. Engineering stress-engineering strain data of a target metal material under dynamic tension are obtained and preprocessed. Based on the mechanical properties of the material, an engineering strain analysis range is determined. According to the engineering strain analysis range, elastic modulus analysis data are determined from the engineering stress-engineering strain data. Based on the elastic modulus analysis data, linear fitting is performed to determine a first fitting curve. Based on the elastic modulus analysis data and the first fitting curve, the engineering strain analysis range of the target metal material is redetermined. Based on the redetermined engineering strain analysis range, linear fitting is performed to determine a second fitting curve. The slope error between the first fitting curve and the second fitting curve is determined, and in the case where the slope error meets a preset error value, the slope of the second fitting curve is taken as the elastic modulus of the target metal material.

The invention belongs to the technical field of welding joint material characterization, and particularly relates to a method, system, equipment and medium for obtaining a welding joint high-precision model, and the method comprises the following specific steps: preparing a sample, carrying out a tensile experiment on the sample, determining a corresponding engineering stress-strain curve, establishing a finite element model, and outputting the engineering stress-strain curve of simulation inversion. And performing comparison iteration, calibrating and optimizing material parameters, and finally obtaining a high-fidelity welding joint material model. According to the method, the anisotropy property of the material performance of the whole area of the welding joint is fully considered, and three typical types of a base metal area, a heat affected area and a welding seam area are covered. A miniature sample local performance testing method is introduced, and accurate description of the mechanical property of the whole-area material of the welded joint is achieved. The method is suitable for different welding processes and various joint structure forms, has high universality, and can remarkably improve the safety evaluation simulation precision of the welding structure in a real service state.

The present application provides a macroscopic finite element simulation analysis method and device for seals considering plastic deformation, which belongs to the field of seal design. The method includes: obtaining the engineering stress-strain curve of the plastic material under compression; converting the engineering stress-strain curve into a true stress-strain curve; determining the yield limit, and using the strain point corresponding to the yield limit as the dividing point between elastic and plastic deformation; extracting the elastic section of the true stress-strain curve, calculating the elastic modulus, and obtaining the Poisson's ratio by measuring the axial and lateral strains in the uniaxial compression test; extracting the plastic section of the true stress-strain curve, and establishing a multilinear isotropic hardening model; constructing a complete elastic-plastic constitutive model covering the elastic deformation zone and the plastic deformation zone; simulating the stress distribution, strain response and contact performance of plastic seals under compression deformation. The method and device provided in the present application can solve the problem that the existing seal simulation only uses the elastic modulus and Poisson's ratio, resulting in results that are inconsistent with reality.

The invention discloses a steel structure residual mechanical property evaluation method based on steel strain aging, and relates to the technical field of material mechanics. According to the method, the mechanical property change shown after the steel is subjected to plastic damage, namely the steel strain aging effect, is taken as a core, and a steel engineering stress-engineering strain curve under different strain aging conditions is tested by adopting a two-stage test method; and establishing an evolution equation of the steel strain aging mechanical property index along with the plastic damage degree and a constitutive model of the steel strain aging mechanical property index. Based on a strain aging mechanical property constitutive model, a two-stage numerical simulation method is adopted to carry out refined numerical analysis on the residual mechanical properties of the steel structure with plastic damage. The technical bottleneck of plastic damage and strain aging effect coupling treatment in traditional finite element analysis is broken through, and a reliable quantitative evaluation method is provided for residual mechanical property evaluation of the steel subjected to plastic damage. The method for evaluating the residual mechanical properties of the steel structure has a wide application prospect.

The invention belongs to the field of aero-engines, relates to a bilinear constitutive curve design technology, and discloses a bilinear constitutive parameter engineering establishment method, system and equipment and a medium. The method comprises the steps that a part made of a to-be-calibrated material is adopted, and bilinear constitutive parameter initial values are obtained according to tensile mechanical property data; according to the bilinear constitutive parameter initial value, elastic-plastic finite element analysis is conducted on the part, and first engineering stress and first engineering strain of the part under the working load and engineering residual strain of the part after the working load is unloaded are obtained; carrying out a working load loading and unloading test to obtain the real residual strain of the part; and evaluating and correcting the initial value of the bilinear constitutive parameter through the engineering residual strain and the real residual strain. According to the method, the constitutive curve capable of meeting engineering use is obtained through the tensile mechanical property data, data support is provided for strength design of engine parts, and the method has the advantages of being few in needed parameters, easy to operate and high in engineering operability.

The application provides a sleeve size parameter determination method based on surrounding rock borehole radial stiffness damage evaluation, and relates to the field of mechanics and test technology.The method comprises the following steps: according to the mining stress condition of the engineering site roadway surrounding rock, the basic mechanics parameters of the surrounding rock and the actual situation of the anchor rod support, the sleeve material selection and length parameters of the anchoring base body are determined in combination with the indoor test; the thickness parameters of the sleeve are determined on the basis of the engineering site, the anchoring borehole damage is judged, the stiffness damage of the anchoring hole is closely related to the plastic deformation and the rock modulus damage law, therefore, the plastic zone radius of the anchoring borehole is analyzed in combination with the engineering stress and the lithology condition, the modulus damage degree of the surrounding rock around the borehole is evaluated on the basis of the rock elastic modulus damage evolution law test and the theoretical analysis, and then the radial stiffness damage coefficient of the anchoring borehole is given, and finally, the thickness parameters of the anchoring base body sleeve are determined according to the equivalent mechanics of the engineering surrounding rock borehole and the sleeve radial stiffness, so that the scientificity of the sleeve parameter determination is ensured.

The present invention discloses a method for adjusting the extrapolated hardening curve of a material, comprising the steps of: 1. Starting a uniaxial tensile experiment on the material and obtaining an engineering stress-strain curve; 2. Obtaining an experimental hardening curve from the engineering stress-strain curve of the material; 3. Supplementing the true strain of the experimental hardening curve to 1, i.e., the model fitting curve; 4. Taking a tangent line at the necking point of the experimental hardening curve; 5. Generating a Bézier curve using a second-order Bézier curve, i.e., the extrapolated hardening curve; 6. Adjusting the shape and stress value of the Bézier curve by controlling the parameters x1 and y2 to make the Bézier curve coincide with the model fitting curve and determining the reference values of x1 and y2; 7. Adjusting the extrapolated hardening curve according to actual needs. The present invention can determine the extrapolated hardening curve through three points, realize the adjustment of the extrapolated hardening curve by adjusting the parameters of the Bézier curve, and smoothly connect with the experimental hardening curve, meeting the requirements for identifying the material flow curve during the material tensile experiment and simulation benchmarking process.

The application discloses a metal material cumulative damage model and a calibration method thereof, and the calibration method comprises the following steps: (1) carrying out uniaxial cyclic loading test to obtain an engineering stress-strain curve of the material; (2) calculating the Young's modulus E under different engineering strains; (3) calculating the cumulative damage D under different strains and obtaining data points of the cumulative damage and the engineering strain; (4) converting the data points of the cumulative damage and the engineering strain into data points of the cumulative damage and the equivalent plastic strain; and (5) calibrating the cumulative damage model parameters. Through the construction of the cumulative damage model and the design of the cyclic control conditions of the model parameter calibration test, the application realizes simple, fast and low-cost metal material cumulative damage test and fitting, obtains the equivalent plastic strain-cumulative damage curve which is closer to the actual situation of the metal material, and overcomes the problem that the existing model cannot accurately describe the cumulative damage behavior of the material.

The invention discloses a method for constructing a high-strength steel stress-strain constitutive model, which comprises the following steps of: (1) performing a tensile test on high-strength steel to obtain engineering strain and engineering stress data; (2) converting the engineering stress into real stress by utilizing a formula (I), and converting the engineering strain into real plastic strain by utilizing a formula (II); (3) carrying out piecewise fitting on the real stress and real plastic strain data by adopting a piecewise function; and (4) obtaining the stress-strain constitutive model of the high-strength steel through the steps. According to the method, a new constitutive model is innovatively constructed according to the strain hardening characteristics of the advanced high-strength steel, the constitutive relation of the stress-strain curve is accurately represented by adopting a segmented fitting method, the characteristic of high representation precision is achieved, and the goodness of fit of the constitutive model is larger than 0.9999. The constitutive model obtained through the method can be directly used for forming simulation, strength simulation analysis and the like, and technical data are provided for new automobile model development.

The invention discloses a thrust chamber inner wall bearing strength evaluation method, device, equipment and medium, and relates to the field of material analys.The thrust chamber inner wall bearing strength evaluation method comprises the steps that a test load-displacement curve and a test engineering stress-strain curve of a ductile copper alloy test piece are obtained; determining a first constitutive parameter of the ductile copper alloy according to the test engineering stress-strain curve; performing a tensile simulation test on the finite element model of the ductile copper alloy test piece, and determining a second constitutive parameter of the ductile copper alloy when a simulation load-displacement curve generated by the tensile simulation test is consistent with the test load-displacement curve; and based on the first constitutive parameters and the second constitutive parameters, thrust chamber bearing strength evaluation is conducted on the thrust chamber constructed by the ductile copper alloy, and then the bearing capacity of the inner wall of the engine thrust chamber is accurately analyzed.

The invention discloses a metal material plasticity large deformation constitutive parameter obtaining method and a product, the method comprises the following steps: carrying out a tensile test of a standard test piece to obtain an engineering stress-strain curve, converting a uniform deformation part into a real stress-strain curve by adopting a theoretical formula, and converting a softening section into a real stress-strain curve by adopting a theoretical formula; the method comprises the following steps: establishing a finite element model of a standard test piece, carrying out tensile simulation iteration, adjusting a stress-strain curve used in numerical simulation by comparing the difference between the stress-strain curves obtained by numerical simulation and test, and carrying out loop iteration to enable the stress-strain curves to be consistent with the actual stress-strain curve of the material. The plastic large deformation performance characterization of the material is realized; the method is convenient to implement, the obtained parameters can completely and reliably reflect the material mechanical characteristics of the material in the elastic section and the plastic section, and when the method is applied to structural response analysis, large deformation and even damage of the material can be more accurately reflected.