90 results about "Strain stiffening" patented technology

The present invention relates to the technical field of concrete. Disclosed is a toughening design method for fiber-reinforced concrete. The method of the present invention changes the passive control characteristics of fibers on a concrete crack propagation process in conventional fiber-reinforced concrete. Starting from the origin of composite material design, firstly, an ultrahigh-ductility composite cementitious matrix is designed; and secondly, an aggregate is incorporated. On the basis of a specific combination of matrix and aggregate parameters, a composite material develops meso-scale multiple cracking and strain-hardening behaviors between aggregate particles during external loading. The fiber-reinforced concrete prepared by this method actively disperses brittle damage and failure within the material, and avoids unstable crack propagation caused by weak interfacial bonding between the aggregate and the matrix. Compared to conventional fiber-reinforced concrete design methods, the present invention more accurately establishes relationships between material compositions, microstructures and macroscopic mechanical response, and more efficiently enhances the toughness of the material.

The invention discloses a foundation pit excavation and support cooperative control method based on finite element dynamic feedback, which comprises the following steps: S1, establishing a foundation pit support finite element model, defining constitutive parameters of a soil body small strain hardened soil model HSS and support structure rigidity, and obtaining an initial displacement field and a stress field through step-by-step excavation simulation; and S2, iteratively calibrating parameters based on the simulation result and the field monitoring data, and constructing a construction stage dynamic adjustment threshold library which comprises a displacement warning value (UXmax), a stress safety coefficient (SF is greater than or equal to 1.3) and a support activation time sequence. According to the method, dynamic parameter iteration is achieved, a finite element model is reversely optimized through monitoring data, and the parameter solidification problem of a traditional method is solved; automatic closed-loop control is achieved, manual intervention is reduced, and the response speed is increased to the minute level; and economical efficiency is improved, waste of materials such as steel is reduced through accurate control, and the comprehensive cost is reduced by 15%-25%.

The invention belongs to the technical field of optimization design of concrete materials, and particularly relates to a multi-objective optimization method of a strain hardening alkali-activated concrete material, which comprises the following steps: selecting an experimental material, setting a plurality of alkali-activated mortar mixing ratios, and predicting the performance of alkali-activated mortar based on a response surface method; performing parameter analysis based on the response curved surface model, and constructing a response index prediction model; based on the response index prediction model, defining basic parameters; the response indexes are considered, alkali-activated mortar multi-objective optimization is carried out through an NSGA-II algorithm, and a Pareto leading edge is obtained; determining an optimal compromise solution set based on a Pareto leading edge; based on the optimal compromise solution set, determining the objective weight of each response index by adopting an entropy weight method; based on the determined objective weight of each response index, performing multi-target evaluation on the alkali-activated mortar mix proportion in the optimal compromise solution set by adopting an ideal approximation algorithm to obtain an optimized alkali-activated mortar mix proportion; and the performance optimization of the strain hardening alkali-activated concrete material is indirectly realized.

The invention relates to ultra-low carbon steel, a preparation method thereof and a steel product. The preparation method of the ultra-low carbon steel comprises the following steps: providing a casting blank; sequentially heating and hot-rolling the casting blank to obtain hot rolled steel; the hot rolling comprises rough rolling and finish rolling which are sequentially carried out, the initial rolling temperature of the rough rolling is 990-1040 DEG C, and the outlet temperature of the rough rolling is 900-940 DEG C; the initial rolling temperature of finish rolling ranges from 840 DEG C to 890 DEG C, and the final rolling temperature of finish rolling ranges from 750 DEG C to 830 DEG C; and the hot rolled steel is sequentially subjected to acid pickling, cold rolling and annealing. According to the preparation method, ferrite area low-temperature rolling is adopted, the heating energy consumption is remarkably reduced, the production efficiency is improved, the problem of scale thickening caused by traditional high-temperature rolling is avoided, the surface quality of the strip steel is more uniform, and the pickling cost is greatly reduced. Meanwhile, the ductility, the strain hardening index (n value) and the plastic strain ratio (r value) of the obtained finished product are remarkably improved, and the forming performance is excellent.

The invention discloses a numerical simulation analysis method for a near-river ultra-deep foundation pit under the action of seepage flow, and the method comprises the following steps: S1, constructing a three-dimensional numerical model based on finite element software PLAXIS 3D, and constructing a non-uniform stratum model in combination with a Borehole module; s2, fine modeling is conducted through the underground diaphragm wall, the reinforced concrete supports and the latticed columns; s3, simulating a small strain hardening characteristic and a rigidity attenuation effect of the soil body by adopting an HSS model; s4, simulating underground water flow by combining plastic steady-state seepage analysis, and simplifying the three-axis cement mixing pile into an underground diaphragm wall structure through an equivalent stiffness principle; and S5, step-by-step excavation and support sequential control construction procedures are adopted, and finally, the reliability of the model is verified by comparing a horizontal displacement simulation result of the diaphragm wall with field monitoring data. According to the method, the foundation pit deformation rule is predicted through HSS constitutive model and seepage coupling analysis, and the foundation pit deformation prediction precision is remarkably improved.

A composite copper-based current collector and a preparation method therefor, and a lithium ion battery, relating to the technical field of battery materials. The composite copper-based current collector comprises: a polymer substrate film; and a modified copper layer arranged on at least one surface of the polymer substrate film, wherein the modified copper layer comprises a C-Cu heterogeneous microstructure with dispersed carbon quantum dots. Carbon quantum dots are introduced, and the carbon quantum dots are uniformly dispersed in copper grains and at copper grain boundaries, thereby forming the C-Cu heterogeneous microstructure with dispersed carbon quantum dots; the presence of the carbon quantum dots can exert resistance to grain coarsening, thereby inhibiting grain coarsening and promoting grain refinement, improving the tensile strength of the composite copper-based current collector; the C-Cu heterogeneous microstructure can enhance dislocation storage capacity and strengthen strain hardening, thereby improving the elongation at break of the composite copper-based current collector; and improvements of the tensile strength and the elongation at break jointly enhance mechanical properties of the current collector, and improve the stability of the current collector in the battery.

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 invention relates to an electric arc additive mixed end plate connecting device and a performance prediction method, and the method comprises the steps: manufacturing a WAAM end plate at the end part of a conventional steel pipe through multi-axis metal 3D printing, and forming a mixed connecting piece; the two mixed connecting pieces are in butt joint through high-strength bolts to form the mixed end plate connecting device; geometric characteristic parameters of the mixed end plate connecting device are obtained by adopting a three-dimensional scanning technology, and the mechanical response of the mixed end plate connecting device is measured by combining a four-point bending test with a digital image correlation technology; and on the basis of the geometrical characteristic parameters and the mechanical response data, the yield bearing capacity is predicted through a correction yield line analysis method, and the ultimate bearing capacity is predicted by adopting an equivalent beam model considering the strain hardening effect. The device and the method have the beneficial effects that geometric characteristic measurement, interface connection characteristic and yield performance test, bearing prediction evaluation and application design of the mixed end plate connecting device combining the electric arc additive manufacturing stainless steel, low-carbon steel and high-strength steel end plates with the conventional steel pipe can be effectively realized.

A method for toughening of fiber-reinforced concrete in the field of concrete technologies is disclosed. The method comprises (1) design of mortar matrix; (2) design of ductile composite mortar with strain-hardening characteristic; (3) iterative design between the ductile composite mortar and aggregate; and (4) load-carrying capacity verification and optimization. In the process of external loading, mesoscale multiple cracking and strain-hardening behaviors are developed in the interstitial matrix between adjacent aggregate particles.

The invention discloses a high-performance dielectric elastomer film, a driver capable of being driven at low voltage and a preparation method of the driver. According to the preparation method of the high-performance dielectric elastomer film, customization and balance of mechanical properties and electrical properties of a dielectric elastomer are realized by regulating and controlling the proportion of a chemical cross-linking agent, a high-polarity physical cross-linking agent and a monomer; according to the preparation method of the driver capable of being driven at the low voltage, a dielectric elastomer film and a flexible electrode are stacked through an optimized dry stacking method, the dielectric elastomer driver of a multilayer structure is constructed, and the driver has excellent performance under the low driving voltage. The preparation method has the potential of large-batch and large-scale production, and the prepared dielectric elastomer film has low Young modulus and enhanced strain hardening effect, can avoid electromechanical coupling instability, has high dielectric constant, has large-area strain in a low electric field, and can be used for preparing a dielectric elastomer film. The resulting dielectric elastomer driver can have a blocking force of 0.8 N and an energy density of 80 J / kg at a voltage of 500 V.

The invention belongs to the field of automobile steel manufacturing, and particularly relates to 400 MPa-grade high-strength cold-rolled automobile inner and outer plate steel based on an ultra-fast heating and continuous annealing technology and a preparation method of the 400 MPa-grade high-strength cold-rolled automobile inner and outer plate steel. The steel comprises the following chemical components in percentage by mass: 0.003%-0.008% of C, 0.3%-0.7% of Mn, 0.01%-0.08% of Si, 0.02%-0.06% of Ti, less than or equal to 0.03% of P, less than or equal to 0.002% of N, less than or equal to 0.005% of S and the balance of Fe and inevitable impurities. The yield strength of the steel plate is 240-320 MPa, the tensile strength is 400 MPa or more, the percentage elongation after fracture A80 is 36% or more, the plastic strain ratio r is 2.0 or more, and the strain hardening index n is 0.2 or more.

The present application relates to the technical field of ultra-high performance concrete, and particularly relates to a light sand modified ultra-high strain hardening ultra-high performance concrete. The light sand modified ultra-high strain hardening ultra-high performance concrete comprises the following raw materials in parts by mass: cementitious material 55-65 parts, fine aggregate 0-48 parts, light sand 0-5 parts, steel fiber 6-10 parts, and water 10 parts; the volume ratio of the fine aggregate to the light sand is 0-18:18-0, and the sum of the volume of the fine aggregate and the volume of the light sand is always the same. The present application improves the strain hardening grade of UHPC to more than 1.5 times, thereby obtaining an ultra-high strain hardening UHPC, which has a stronger crack width control ability compared with the traditional strain hardening type UHPC, and is particularly suitable for UHPC structure application in marine environment.

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 invention relates to the field of bridge damping, in particular to a near-fault bridge anti-seismic toughness improving device and a test method thereof.The bridge comprises T-beams, a cover beam, a diaphragm plate between every two adjacent T-beams and an ECC column located between the two T-beams; two pairs of SMA disc spring devices are arranged on the ECC column body, one pair of SMA disc spring devices are arranged towards the T beam, and the other pair of SMA disc spring devices are arranged towards the transverse partition plate; the SMA disc spring devices are used for enabling the T beams to recover to the initial positions through the recovery characteristic of the SMA disc spring devices after relative displacement of the bridge in the transverse bridge direction occurs, and the ECC column is arranged between the two T beams of the bridge, so that the T beams can be recovered to the initial positions. The limit tensile strain of the ECC (fiber cement-based composite material) material can reach more than 200 times that of the traditional concrete, and the ECC material is accompanied by the multi-crack cracking phenomenon of fine cracks, so that the strain hardening characteristic of a similar metal material under the tensile effect is formed, and the structural deformation caused by earthquakes can be effectively dealt with.

The invention provides a quantitative evaluation method for micro-area comprehensive mechanical properties of an electron beam welding joint, and belongs to the technical field of material mechanical property evaluation.A load-displacement curve is obtained through a nanoindentation test, and a data processing method combining numerical integration and high-order derivative calculation is adopted, so that the comprehensive mechanical properties of the electron beam welding joint are evaluated. Meanwhile, three performance parameters of strength, plasticity and strain hardening are extracted, and a quantitative mapping relation between the three performance parameters and the microcell structure is established. The method solves the problem of mechanical property quantitative evaluation of gradient structures of a fusion zone, a heat affected zone and a base metal zone of a welding joint, and the problems of high cost, low efficiency, single parameter and the like in the existing evaluation technology.

The application discloses a kind of unbound post-tensioned prestressed fabricated column foot and post-earthquake rapid repair method, belong to building structure seismic and fabricated steel structure technical field.The column foot includes base plate, steel column, friction layer, strain hardening cement-based composite sleeve, vertical prestressed steel bar and cover plate;The friction layer uses block type structure, and is spliced by several friction layer monomers;Vertical prestressed steel bar is threaded through strain hardening cement-based composite sleeve and cover plate, and is fixed cover plate and applies prestress to vertical prestressed steel bar by disc spring group and anchor nut being set to its top end, realizes the unification of " high seismic, easy construction, fast repair ".The application also discloses the post-earthquake rapid repair method of the column foot, including post-earthquake evaluation, elastic self-resetting, installing temporary support, in-situ jacking, lateral replacement, resetting tensioning and the like steps, using unbound characteristics, without lifting off steel column can be completed in 3-4 hours friction layer replacement.

The present invention provides an ionomer having high strain-hardening properties and excellent moldability.　The ionomer contains: a structural unit (A) derived from at least one member selected from the group consisting of ethylene and an α-olefin having 3 to 20 carbon atoms; a structural unit (B) having at least one member selected from the group consisting of a carboxyl group and a dicarboxylic acid anhydride group; and a structural unit (C) having a carboxylic acid metal salt group. The ionomer has 50 or fewer methyl branches per 1,000 carbon atoms or has a total number of ethyl and butyl branches of less than 4.2 per 1,000 carbon atoms. When the maximum elongation viscosity after strain hardening is defined as ηmax(t1), a time t in question is defined as t1, and an approximate straight line of the elongation viscosity before stain hardening is defined as ηlin(t), ηmax(t1) and ηlin(t1) satisfy ηmax(t1)> ηlin(t1), and further satisfy formula (α) or (β).　Formula (α): ηmax(t1)>1.9 ηlin(t1)1.1 Formula (β): ηmax(t1)≥1.9 ηlin(t1)0.7

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 discloses a method for analyzing nonlinear dynamics and stress wave propagation characteristics of a dielectric elastomer actuator structure. The method considers the strain hardening effect and viscoelasticity of the dielectric elastomer material, establishes a dynamic model of the dielectric elastomer actuator structure from linear damping assumption and considering material viscoelasticity respectively, calculates the equilibrium deformation and inherent frequency of micro-vibration near the equilibrium state, studies the nonlinear dynamic response of the structure under alternating voltage load, explores the influence law of the constitutive parameters on the nonlinear dynamic response, and analyzes the internal relationship between material viscoelasticity and structure vibration damping. In addition, considering compressibility, the stress wave propagation characteristics in the finite deformation state are studied, the separation phenomenon of transverse wave and longitudinal wave is analyzed, and the influence of the constitutive parameters and strain hardening effect on the stress wave propagation characteristics is explored. The application can provide a theoretical basis for the fine design of the dielectric elastomer actuator and the control of stress wave propagation by adjusting the electric field.

This disclosure provides a polyether-ester elastomer with a high stain hardening ability, wherein the thermoplastic polyether-ester elastomer contains polyester hard segment, polyether soft segment and at least one inorganic compound. The inorganic compound is selected from the group consisting of silicon dioxide, titanium dioxide, zinc oxide, aluminum oxide, aluminum silicate, zirconium oxide, potassium titanate and derivatives thereof. This disclosure also provides a polyether-ester elastic fiber which is characterized by a stress-strain curve with a specific profile. This disclosure also provides a process for preparing the polyether-ester elastomer, a process for preparing the polyether-ester elastomer fiber, use of the polyether-ester elastomer or polyether-ester elastomer fiber, and a polyether-ester elastic material comprising the polyether-ester elastomer.

This invention discloses a fitting method for the Johnson-Cook constitutive model of PtW7Ir1 alloy ultrafine wire drawing, belonging to the field of numerical simulation technology for metal material processing. This invention extracts three coefficients from the JC constitutive model and obtains the true stress-strain by conducting room temperature quasi-static uniaxial tensile tests on standard PtW7Ir1 alloy specimens. Then, it solves for the yield strength A and elastic modulus of the PtW7Ir1 alloy. Using the Hollomon's rule and the JIA rule, it obtains the strain hardening modulus B and hardening exponent n. Based on the yield stress data obtained from the tensile test, it calculates the strain rate strengthening coefficient and thermal softening exponent using the least squares method to complete the fitting of the constitutive model. This invention obtains JC constitutive parameters applicable to this alloy and, by introducing the Hollomon's rule and the JIA rule, accurately predicts the true hardening behavior of the material after necking, enabling the constitutive model to more realistically reflect the mechanical response of the material under cumulative deformation in multiple drawing passes.

The invention discloses a movable segment beam wet joint UHPC rapid closure construction method which comprises the following steps: S1, wet joint arrangement: wet joints are located in the midspan of a side span, the midspan of a middle span and two sides of the top of a transition pier of each box beam, and the length of the wet joints is 8-20 cm; s2, a closure section is hoisted, a wet joint locking device and a formwork are installed, specifically, a temporary positioning device is installed to lock the box girders on the two sides and the closure section, and then the wet joint formwork is installed; s3, wet joint mixing is conducted, specifically, strain hardening type UHPC is mixed on the beam face through a UHPC mixer, and after mixing is completed, the mixture is put into a pouring hopper of 1 cubic meter; s4, closure section wet joint concrete is poured, specifically, a bridge girder erection machine lifting crown block is adopted to lift a pouring hopper to a wet joint for pouring, and for the position with the pouring height larger than two meters, a chute is arranged on site for discharging; and S5, formwork dismantling, wherein after the joint strength of the closure section reaches the concrete strength standard, the wet joint formwork and the temporary positioning device are dismantled.

The present application relates to a safety monitoring method and system based on the Leeb hardness of metal components, wherein the method includes: establishing a mathematical correlation model between the Leeb hardness, yield strength, and strain hardening index of a metal material; detecting the Leeb hardness and strain hardening index of a metal component manufactured based on the metal material, and calculating the yield strength of the metal component through the mathematical correlation model; and determining whether the metal component meets the safe service requirements of the unit component based on the yield strength of the metal component. Through this application, the problem of how to accurately monitor the service safety of metal components based on Leeb hardness is solved. The influence of the Leeb hardness and strain hardening index of the metal material on the yield strength is comprehensively considered, and the construction of a mathematical correlation model is realized. Based on the model, the yield strength of the metal component is accurately calculated to determine whether it meets the safe service requirements.

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.

Disclosed is a polyamide block copolymer which comprises: a polymer block (A) that has a glass transition temperature of more than 20°C; and a polymer block (B) that has a glass transition temperature of 20°C or less. The polymer block (A) contains 50 mol% or more of a constitutional unit that is derived from a semiaromatic polyamide. The polyamide block copolymer has a complex shear viscosity η0 of 500-10,000 (Pa∙s) at an angular frequency of 6.28 rad∙s- 1 and a strain hardening parameter H of 1.5 or more.

An electromechanical actuator includes a planetary rolling screw drive having a plurality of planets, a driven cage guiding the plurality of planets, and a threaded spindle. The threaded spindle has a formed thread with a finish produced by martensite precipitation and strain hardening. The threaded spindle is formed from a steel including 0.4 to 1.5% by weight of Carbon, 12.0 to 22.0% by weight of Manganese, up to 4.0% by weight of Chromium, up to 0.5% by weight of Nickel, up to 0.3% by weight of Copper, up to 0.3% by weight of Vanadium, up to 0.3% by weight of Sulfur, up to 0.1% by weight of Phosphorus, up to 4.0% by weight of Silicon, up to 0.05% by weight of Aluminum, and a remainder of iron and smelting-induced impurities.

The present invention relates to a steel structure member, specifically an intelligent design method for stainless steel structure members based on a generative adversarial network, belonging to the field of steel structure applications. A feature mapping relationship is established between the design parameters and design schemes of stainless steel structure members, making full use of the strain hardening ability, plastic deformation ability of stainless steel materials, and the post-buckling bearing capacity of members, and finally providing a relatively accurate and economical design scheme for stainless steel structure members, such as the member cross-section type, cross-section size, etc. The present invention can more accurately consider the material properties of stainless steel, and on the premise of ensuring safety and reliability, achieve the refined design of the cross-section of stainless steel members, reducing material waste caused by low design accuracy.

Provided is a steel sheet suitably used for an automobile structural member and the like, and more particularly, to a steel sheet having high strength and excellent formability that may prevent processing defects such as cracks or wrinkles occurring during the press-forming, and a method for producing the same.

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.