13 results about "Strain hardening exponent" patented technology

The invention provides a material constitutive parameter inversion method which can be applied to the technical field of artificial intelligence. The material constitutive parameter inversion method comprises the following steps: acquiring an elastic modulus and an actually measured load depth curve of a to-be-tested material in a single nanoindentation test; performing extrapolation translation preprocessing on the actually measured load depth curve to obtain an equivalent ideal curve; carrying out characterization processing on the equivalent ideal curve to extract input characteristic parameters which comprise press-in rigidity, unloading rigidity and plastic work proportion; the indentation rigidity, the unloading rigidity, the plastic work ratio and the elastic modulus are input into a pre-trained indentation constitutive mapping model to predict the yield strength and the strain hardening index of the to-be-tested material, and the indentation constitutive mapping model is a full-connection back-propagation neural network pre-trained through a finite element virtual test sample. The invention further provides a material constitutive parameter inversion system and device, a storage medium and a program product.

The application provides a battery device and a power utilization device. The battery device comprises a box body, a battery monomer and a protection plate. The battery monomer is contained in the box body, and the protection plate is connected to the box body. The protection plate comprises a first fiber resin layer and a reinforcing plate. The first fiber resin layer is arranged on at least one side of the reinforcing plate along the thickness direction. The elongation after fracture e1 of the reinforcing plate is greater than or equal to 28%, and the strain hardening index N of the reinforcing plate is greater than or equal to 0.27. The battery device provided by the application is beneficial to reducing the risk of deformation of the protection plate and the risk of fracture of the protection plate.

The invention belongs to the technical field of material performance evaluation, and provides a metal material cavitation erosion incubation period prediction method based on surface plastic deformation analysis. The method comprises the following steps: carrying out cavitation erosion test on a sample; measuring the surface profile length of the sample in the cavitation environment, and calculating the surface area increment rate of the sample; drawing a surface area increment rate-time change curve, and obtaining an incubation period demarcation point and an incubation period end point of the sample; predicting the incubation period of the actual equipment according to the incubation period demarcation point and the incubation period end point; by analyzing the surface area increment rate of the material exposed in the cavitation environment, the incubation period is divided into two stages dominated by hardness and strain hardening indexes, a quantitative relation with the material performance is established, and non-destructive life prediction is achieved.

The application provides a tunnel surrounding rock grouting reinforcement process simulation analysis method and system, relates to the tunnel surrounding rock reinforcement simulation technical field, and effectively improves the spatial resolution of the surrounding rock deformation state monitoring through the arrangement of multiple evaluation interfaces in the tunnel axis direction and the multi-point synchronous strain collection; the volume strain hardening index normalization analysis can dynamically and quantitatively reflect the mechanical property evolution of the surrounding rock after being compressed; the volume strain of the surrounding rock is dynamically coupled with the rheological test parameters of the grouting material, the timeliness and accuracy of the slurry permeability and pressure correction are improved; the linear interpolation method is used to realize the continuous distribution calculation of the grouting pressure in the tunnel axial direction, and the simulation analysis is significantly improved in the refinement and practicability.

The application belongs to the technical field of stainless steel preparation, and discloses a cold-deformable and heat-treatable hardening Ni-free high-strength stainless steel and a preparation method thereof. The stainless steel comprises the following components in percentage by mass: Cr: 13-15%, C: 0.25-0.4%, Mn: 0.5-2%, Cu: 0.1-3%, Mo: 2-3%, Si: 0-0.5%, and the balance of Fe and inevitable impurities. The stainless steel does not contain Ni element, has a low work hardening rate (strain hardening index n≤0.185) and a fracture elongation rate of more than 20% in a soft state (annealed state), is cold-deformable, and has low raw material and processing costs; after quenching and aging heat treatment, the stainless steel not only has an optimal combination of strength and toughness (yield strength and tensile strength are more than 1300 MPa and 1600 MPa respectively, and elongation is greater than 10%), but also has a high yield strength ratio.

The invention provides a tunnel surrounding rock grouting reinforcement process simulation analysis method and system, and relates to the technical field of tunnel surrounding rock reinforcement simulation. A plurality of evaluation interfaces are arranged in the axial direction of a tunnel and multi-point synchronous strain acquisition is performed, so that the spatial resolution of surrounding rock deformation state monitoring is effectively improved; volumetric strain hardening index normalization analysis is adopted, and the mechanical property evolution of the surrounding rock after being pressed can be dynamically and quantitatively reflected; surrounding rock volume strain and grouting material rheological test parameters are dynamically coupled, so that the timeliness and accuracy of grout infiltration capacity and pressure correction are improved; continuous distribution calculation of the grouting pressure in the axial direction of the tunnel is achieved through a linear interpolation method, and refinement and practicability of simulation analysis are remarkably improved.

This invention discloses a method for producing dual-phase steel strip for automotive structures, comprising: (1) a smelting-continuous casting process, wherein the steel composition supplied to the casting machine by mass percentage is C: 0.05-0.40%, Si≤1.50%, Mn: 1.0-3.0%, P≤0.050%, S≤0.030%, Alt: ≤0.050%, Cr: 0.10-1.00%, Ca: 0.0005-0.0030%, with the remainder being Fe and impurities; (2) a hot rolling process; (3) a pickling and cold rolling process; and (4) a continuous hot-dip galvanizing and finishing process. The purpose of this invention is to provide a method for producing dual-phase steel strip for automotive structures. The dual-phase steel strip for automotive structures of this invention has the characteristics of high strength, high strain hardening index, good strength and ductility matching, and high corrosion resistance.

The invention discloses a manufacturing method of an IF steel plate with uniform surface and core structures and a product of the IF steel plate, and relates to the technical field of automobile steel manufacturing. The manufacturing method comprises the following steps: in the procedure of controlling an annealing section, the dew point temperature of a heating section is-25 to-35 DEG C, the dew point temperature of a soaking section is-36 to-46 DEG C, and the dew point temperature of a slow cooling section is-38 to-48 DEG C; and excessive Ti in the steel plate components is controlled to be greater than or equal to 0.001%. The method solves the problem that the surface grain structure and the core structure of the annealed IF steel plate are not uniform, so that the surface structure and the core structure of the annealed IF steel plate are consistent, the overall structure is uniform, and the longitudinal stripe defect occurring after the steel plate is stamped is effectively improved. According to the finished product performance of the product prepared through the manufacturing method, the yield strength ranges from 120 MPa to 180 MPa, the tensile strength ranges from 270 MPa to 310 MPa, the ductility is larger than or equal to 38, the plastic strain ratio r value is larger than or equal to 2.3, the strain hardening index n value is larger than or equal to 0.22, fiber tissue does not exist on the surface layer, and for a galvanized product, the defect of skip plating does not exist after plating.

The application discloses a yield strength correction calculation method for instrumented indentation method, which comprises the following steps: a target material is subjected to cyclic loading test by using an instrumented indentation tester to obtain a load-displacement curve, and true stress and true strain are obtained by the load-displacement curve, and the true stress and true strain measuring points have all entered a plastic hardening stage, and the yield strength cannot be accurately extrapolated. The instrumented indentation method can very accurately obtain the tensile strength, and it can be considered that no matter whether there is a yield platform, the constitutive curve of the plastic hardening stage of the material constitutive relation remains unchanged, that is, the strengthening coefficient K and the strain hardening index n obtained by fitting the Holloman equation in this part remain unchanged, and due to the existence of the yield platform, the plastic hardening stage of the constitutive curve is translated as a whole to obtain a new constitutive equation, and the influence of the yield platform can be considered. The application improves the precision of the instrumented indentation method in on-site detection of the yield strength of steel structure materials.

The invention belongs to the technical field of metal material mechanical property prediction, and relates to a method for predicting mechanical properties of a material at different temperatures based on dynamic strain aging of a high-temperature alloy. The method comprises the following steps: obtaining a true stress-strain curve of the high-temperature alloy through a tensile test; fitting original data to establish a true stress-strain curve equation; respectively establishing prediction equations of the strain hardening index n, the internal defect saturation strength sigma y and the second-stage hardening rate theta II with the temperature; obtaining a prediction equation of the mechanical properties of the material at different temperatures based on the dynamic strain aging of the high-temperature alloy through the associated equation; and finishing material mechanical property prediction at the specified temperature by utilizing the prediction equation. The prediction method quantifies the influence of the temperature and the dynamic strain aging effect on the high-temperature alloy strength and plasticity matching for the first time, is suitable for the high-temperature alloy and other metal materials with the DSA phenomenon, and has important significance on establishment of the tensile constitutive relation of the high-temperature alloy.

The application discloses a cold upsetting forming method for an oil cylinder for a gas spring, and belongs to the technical field of cold upsetting forming of the oil cylinder for the gas spring.The method comprises the following steps: 1) raw material preparation and shaping; 2) upsetting; 3) concave pressing; 4) reverse extrusion stretching; 5) one-time forming of thin-wall reduced-diameter extension; and 6) two-time forming of thin-wall reduced-diameter extension.Combining the small overall size, the large length-diameter ratio and the thin-wall characteristics of the oil cylinder for the gas spring and the characteristics of batch production, the method adopts the method of first upsetting and then gradual extension, divides the complex structure part into multiple simple stations, adopts the process of upsetting + composite extrusion + multi-step reducing-diameter stretching, and introduces the reduced-diameter distribution formula based on the strain hardening index and the flow stress model, so that the gradual reduction of the inner and outer diameters of the cylinder body and the uniformization control of the wall thickness are realized.On the one hand, the method improves the wall thickness uniformity of the product and avoids the abnormal local wall thickness; on the other hand, due to the adoption of the five-station progressive one-time forming process, the auxiliary clamping time is greatly shortened, so that the forming efficiency is improved.

The invention discloses a production method of 590MPa-grade high-corrosion-resistance zinc-aluminum-magnesium coating dual-phase steel for a new energy automobile battery pack, and stable production of a dual-phase steel strip is realized by optimizing a C-S i-Mn-Cr component system and matching with a specific hot rolling coiling temperature and an annealing process. The obtained dual-phase steel strip meets the requirements that the yield strength is 340-460 MPa, the tensile strength is larger than or equal to 590 MPa, the ductility is larger than or equal to 20%, the strain hardening index is larger than or equal to 0.13, and the dual-phase steel strip is particularly suitable for stamping forming of automobile safety structural parts.

The application provides a material constitutive parameter inversion method, which can be applied to the field of artificial intelligence technology. The material constitutive parameter inversion method comprises the following steps: obtaining the elastic modulus and the measured load-depth curve of the material to be measured in a single nanoindentation test; performing extrapolation translation preprocessing on the measured load-depth curve to obtain an equivalent ideal curve; performing characteristic processing on the equivalent ideal curve to extract input characteristic parameters, wherein the input characteristic parameters comprise indentation stiffness, unloading stiffness and plastic work ratio; and inputting the indentation stiffness, unloading stiffness, plastic work ratio and elastic modulus into a pre-trained indentation constitutive mapping model to predict the yield strength and strain hardening index of the material to be measured, wherein the indentation constitutive mapping model is a fully connected back propagation neural network pre-trained by a finite element virtual test sample. The application also provides a material constitutive parameter inversion system, device, storage medium and program product.