17 results about "Flow stress" patented technology

The application provides a light steel hot deformation constitutive optimization method based on a neural network and precipitation strengthening coupling, and relates to the technical field of metal material hot working and constitutive model establishment; the neural network model automatically learns the nonlinear relationship among the rheological stress, temperature, strain rate and strain, and introduces a precipitation strengthening correction term in a stress prediction term, which is used for representing the competition effect of cutting mechanism and bypass mechanism; through engineering design of precipitation characteristic parameters, base training and strengthening parameter calibration are performed on the neural network model; a damage function optimization algorithm based on a dislocation slip mechanism is further introduced, so that the double constraints of prediction accuracy and physical consistency are realized; the application can realize high-precision flow stress prediction of light steel under different deformation temperatures and strain rates, significantly improves the generalization and physical interpretability of the model, and provides a new modeling approach and theoretical support for constitutive modeling and microstructure and performance control of light steel and other precipitation strengthening type high-strength alloys.

The present invention relates to a low-cost high-ductility fatigue-resistant core energy-dissipation structure and an anti-buckling energy-dissipation support. The core energy dissipation structure comprises at least a first steel plate and a second steel plate. The second steel plate must be and can only be adjacent to and welded to the first steel plate. The microstructure of each of two types of steel plate material used is mainly a ferrite structure; the yield strength and plastic deformation flow stress of the first steel plate material are both higher than that of the second steel plate material. In a plastic deformation strengthening stage, when true strain is not greater than 0.12, the deformation work hardening rate of the first steel plate material is not less than the deformation work hardening rate of the second steel plate material; and under fatigue deformation conditions of a strain amplitude of 1%, a loading frequency of 0.1-0.2 Hz, and a strain ratio of -1, the room-temperature fatigue life of each of the two types of steel plate material is not less than 500 cycles. The ratio of the allowable limit of displacement to the calculated yield displacement of the buckling-resistant energy-dissipation support of the present invention is not less than 7, and the allowable limit of displacement is not less than 1 / 80 of the length of the buckling-resistant energy-dissipation support.

The embodiment of the invention discloses a metal flow stress prediction method and system based on multi-physics field attention, and the method comprises the steps: carrying out the material characteristic coding of the material components and microstructure parameters of a metal material through employing a material characteristic embedding layer of an improved Kolmogov-Arnod network KAN, and obtaining the material characteristics of the metal material; obtaining a characteristic vector of the metal material; carrying out weighted fusion on a plurality of physical field parameters corresponding to isothermal strain measurement by adopting a multi-physical field attention layer of an improved KAN to obtain a high-order feature vector; and performing flow stress prediction on the high-order feature vector and the feature vector based on the temperature value of the isothermal strain measurement by adopting the improved KAN mixed sensing layer to obtain the flow stress of the metal material under the isothermal strain measurement. The accuracy of flow stress prediction can be improved.

The invention belongs to the technical field of protection, and particularly relates to a method and device for evaluating the damage degree of a functional gradient multilayer metal plate under a near-field explosion load. The method specifically comprises the following steps: determining the pulse pressure generated by explosion according to the spatial distribution characteristic of the peak value of the pulse pressure on a loaded surface and the attenuation change rule of the pulse pressure along with time; calculating the plastic work of the first layer of metal according to the plastic strain component expression of the first layer of metal and the incompressibility principle; according to the plastic work of the first layer of metal, the total kinetic energy of the multiple layers of metal plates and virtual work of pulse pressure generated by explosion on virtual displacement, a control differential equation of transverse displacement of the multiple layers of metal plates is obtained; solving the differential equation to obtain the maximum lateral displacement of the multilayer board, calculating the average strain rate according to the maximum lateral displacement, and updating the flow stress; the differential equation is solved again through the flow stress obtained through updating till the set condition is met, and the currently obtained maximum transverse displacement of the multi-layer board serves as the damage degree.

The invention belongs to the technical field of metal material hot working, and provides a method and system for constructing a thermal deformation constitutive model of a spray-formed 2195 aluminum-lithium alloy, and the method comprises the following steps: obtaining flow stress data according to a hot compression test; correcting the flow stress data to obtain calibrated flow stress data; identifying a peak stress and a material constant according to the calibrated flow stress data, and summarizing a Z parameter expression; introducing a strain influence function according to the material constant, and fitting a strain function; and substituting the strain function into the Z parameter expression to obtain a constitutive model. According to the method, the high-precision constitutive model considering the strain influence is established for the extrusion state spray forming 2195 aluminum lithium alloy for the first time, material parameters under different strains are identified through a system, the applicability of the model in a large deformation forming process is remarkably improved, and the prediction error is lower than 5%; a reliable theoretical tool is provided for formulating a hot working process, the trial and error cost is reduced, and the product quality and the structure uniformity are improved.

The present application relates to the turbine disc and compressor disc processing and manufacturing technical field of aero-engine, gas turbine, etc., and discloses a wheel disc mortise broaching force regulation and control method and system, the method comprises the following steps: obtaining broach geometric parameters, broaching process parameters and workpiece material physical properties; based on the broach geometric parameters, the broaching process parameters and the workpiece material physical properties, the shear flow stress on the main shear surface in the cutting process is calculated, and the cutting force considering the strain softening and temperature-strain rate coupling effect is further calculated; based on the broach geometric parameters and the shear flow stress, the edge extrusion force caused by the broach edge roundness radius is calculated; the broaching force and the edge extrusion force are superimposed to obtain the wheel disc mortise broaching force; according to the wheel disc mortise broaching force, the broach geometric parameters and the broaching process parameters are adjusted and controlled, and then the wheel disc mortise broaching force is optimized to meet the actual processing requirements, which provides support for reducing the tool optimization design cost and improving the wheel disc processing quality.

The invention discloses a dynamic strain measurement method, a test block and a testing machine for an ultrahigh-strength material greater than 2GPa. The dynamic strain measurement method comprises the following steps: measuring and acquiring workpiece measurement parameters of each rate test under various rate tests and the highest temperature T of a test section of the test piece; based on the workpiece measurement parameters, actual workpiece parameters are obtained through calculation; and fitting to obtain a dynamic stress-strain curve for simulation analysis based on a plurality of groups of workpiece actual parameters obtained by various rate tests and the highest temperature T of the test section of the test piece. Measurement of the temperature of a test section of a test piece is introduced, temperature measurement parameters are added into the model to construct a new Johnson-Cook constitutive model, a calculation method for correcting strain rate and temperature coupling based on the new Johnson-Cook model is adopted, test data are converted into constitutive parameters capable of being directly used for simulation, and data practicability is improved; and the correction precision of the influence of the introduction of the temperature data on the flow stress is greatly improved. The test piece is prevented from slipping in the clamp by adopting two measures of positioning pins, positioning holes and crossed lines.

The application discloses a damage simulation method based on deform, which comprises the following steps: a macro flow stress constitutive model is established according to stress-strain curves and experimental data of fracture strain under different temperatures and stretching speeds; a material library based on Deform is established by combining basic properties of elastic parameters and thermal performance parameters of the material; a damage prediction module for predicting a forging hot forming process is established, a ductile fracture criterion model is established according to obtained data of influences of the temperature and the strain rate on the strain at the time of fracture, and the temperature, the strain rate in the forging process and fracture in the forming process are predicted.

The application discloses a kind of prediction methods of metal elastoplastic constitutive behavior considering laser shock peening, for the metal material after laser shock peening, residual stress field, grain size distribution field are obtained, combined with elastoplastic theory, considering the flow stress of hot and non-thermal part, the metal elastoplastic constitutive model considering laser shock peening effect is established.At the same time, the residual stress field and microstructure change caused by laser shock peening are introduced into the finite element model, and the material parameters of the corrected metal elastoplastic constitutive model are obtained by finite element model simulation calculation, so as to comprehensively consider various influencing factors of laser shock peening on metal material, calculate the tensile yield curve under different residual stress field and grain size distribution field, so that the prediction accuracy of the mechanical behavior of metal material after laser shock peening is higher.

The application relates to a method for realizing strengthening and toughening of a titanium-based composite material based on high-temperature plastic deformation, comprising the following steps: according to a drawn flow stress and strain relation diagram under deformation temperature and strain rate conditions corresponding to a 30-60% deformation degree, calculating a titanium-based composite material sample deformation energy dissipation rate value eta and a non-stable flow parameter value zeta, and superimposing energy dissipation rate isogram and non-stable flow parameter distribution diagrams drawn respectively under different deformation temperature and strain rate conditions, so as to obtain optimal deformation temperature and strain rate of high-temperature plastic deformation of the titanium-based composite material sample. The application can realize the purposes of strengthening and toughening after high-temperature plastic deformation of the titanium-based composite material, and can be applied to the regulation of mechanical properties of various titanium-based composite materials.

The invention discloses a multi-core copper-tin-titanium / niobium composite blank extrusion process design method based on machine learning, which comprises the following specific steps: carrying out an isothermal thermal compression experiment on a copper-tin-titanium alloy bar to obtain true stress and true strain data; constructing a flow stress-strain constitutive equation and a dynamic recrystallization kinetic model of the copper-tin-titanium alloy according to the true stress and the true strain data; establishing a thermal-mechanical coupling finite element model; constructing a data set according to an output result of the thermal-mechanical coupling finite element model; inputting the data set into a prediction model for training to obtain a trained prediction model; and optimizing hot extrusion process parameters by using the trained prediction model. The method is high in prediction precision, and the design period of the hot extrusion process is greatly shortened.

The application discloses a butt welding joint modeling simulation method based on shell elements, comprising the following steps: based on microhardness testing, dividing a butt welding joint sample into a weld zone, a heat affected zone and a base material zone, and calibrating hardening model parameters for each zone; establishing a shell element model, assigning the hardening model parameters to corresponding shell elements, and correcting the flow stress of the shell elements in the weld zone by the excess height, wherein the correction coefficient K is the maximum load ratio of the reserved excess height sample and the milled excess height sample; defining a nonlinear damage accumulation fracture criterion for the shell elements, wherein the equivalent plastic failure strain is a function of the stress triaxiality; and introducing a grid dependency factor to correct the equivalent plastic failure strain. The application solves the problem of bearing capacity prediction distortion of the shell element model by microhardness partitioning and excess height correction, and realizes accurate prediction of the fracture behavior under a multi-stress state by the stress triaxiality related fracture criterion and grid regularization, and is suitable for large-scale engineering simulation such as vehicle collision.

The application discloses a kind of metal material's flow stress prediction method, device and related equipment.It includes: obtaining the model parameter of the modified Johnson-Cook constitutive model of the metal material to be measured;The modified Johnson-Cook constitutive model is added in Johnson-Cook constitutive model Electric plasticity effect factor, model parameter includes yield stress, strain hardening coefficient, strain hardening index, strain rate hardening coefficient, high temperature softening index and electric plasticity effect coefficient;Determine the plastic strain of the metal material to be measured, plastic strain rate, current deformation temperature and current current density using a predetermined algorithm;It is input into the modified Johnson-Cook constitutive model, and the flow stress of the metal material to be measured is obtained.Thereby, the stress, strain and temperature change of metal material in self-resistance heating process can be more accurately predicted and controlled.

The invention provides a high-entropy alloy friction performance analysis method, system, equipment and medium, and belongs to the field of high-entropy alloy friction performance analysis. A simulation system based on a FeCoCrNiAl0.5 high-entropy alloy matrix and a diamond cutter is established; relaxation and scratching are carried out based on the molecular dynamics model; a crystal defect structure is identified by adopting an atomic coordination number; and determining that the total strain rate is the superposition of elastic and plastic strain rates, determining that the flow stress is composed of dislocation resistance strengthening generated by single crystal FeCoCrNiAl0.5 dislocation interaction and high-entropy alloy lattice distortion strengthening, and processing, analyzing and displaying all obtained strengthening mechanism calculation results. According to the method, the physical model based on the microstructure is established, and the high strength and deformation resistance of the high-entropy alloy are further evaluated. The combined effect of lattice distortion strengthening and dislocation strengthening promotes the high strength of the high-entropy alloy, is superior to a single strengthening mechanism of pure metal, and accelerates the understanding of the mechanical property of high entropy and the atomic scale of a deformation mechanism.

The invention discloses a high-temperature alloy bulk modeling method considering dynamic and static structure genetic effects in a multi-step thermal deformation process, and belongs to the technical field of material plastic processing. The method comprises the following steps: establishing a constitutive model coupled with dynamic microstructure evolution; constructing a static softening fraction model, including description of static recovery, sub-dynamic recrystallization, continuous grain coarsening and annealing twin boundary microstructure evolution behaviors; the static softening fraction serves as a global state variable, key state variables in different deformation stages are iteratively updated, and the key state variables comprise the initial hardening rate, the characteristic stress and the time needed when the dynamic recrystallization fraction reaches 50%; unknown parameters in all the models are calibrated through a genetic algorithm based on experimental data, and accurate prediction of the flow stress and the grain size evolution rule in the multi-step thermal deformation process is achieved. According to the method, the problem of cross-scale association of the microstructure and the macromechanical response in multi-step thermal deformation of the high-temperature alloy is solved.