135 results about "High strain rate" patented technology

The invention discloses a method for evaluating damage evolution of an underground structure under the action of a sudden explosion load, and relates to the technical field of civil engineering and engineering disaster prevention, and the method is characterized by comprising the following steps: S1, simulating the underground structure based on an explosion load, a geometric boundary and material parameters, and constructing a unified constitutive model; and S2, introducing a pressure-related strength criterion of a Dwark-Prasugrel criterion into the unified constitutive model so as to describe the influence of confining pressure on the shear strength. The technical problem to be solved by the invention is to provide the method for evaluating the damage evolution of the underground structure under the action of the burst explosion load, so that the key pain points such as pressure correlation, high strain rate effect, material random discreteness, damage softening energy consistency and the like are difficult to consider at the same time in the existing analysis method. A set of damage evolution evaluation method and implementation system which can be implemented from the material level to the structure level is established, and quantitative prediction and engineering grading judgment of the whole process of crack initiation, expansion to instability failure of the underground structure are supported.

The invention relates to a dynamic puncture test device and method based on high-speed stretching equipment. The device comprises a base, a sensor, a supporting seat, a lower supporting rod, a supporting table, a puncture assembly, a clamping plate assembly, a guide rod, a connecting rod, an upper supporting rod and a gantry pull rod. The method comprises the steps of sample preparation, sample installation, equipment debugging, camera focusing, program setting, data acquisition and the like. The device has the dynamic simulation capability under the condition of high strain rate, can accurately simulate the dynamic puncture behavior of the material under the condition of high strain rate, and provides more representative test data; multi-parameter real-time monitoring and control are achieved, a high-precision sensor and an advanced automatic control system are arranged, and real-time monitoring and adjustment of various parameters such as speed, force and displacement are achieved; the device is suitable for dynamic puncture testing of various materials such as metal, composite materials, high polymer materials and ceramics, and the diversified requirements of different industries are met.

The invention provides an arch-shaped energy dissipation and shock absorption supporting device for a building, which belongs to the technical field of building devices and comprises steel columns, steel beams and arch-shaped energy dissipation and shock absorption supports. The steel columns and the steel beams form a frame structure through high-strength bolts or in a welding mode. The arch-shaped energy dissipation and shock absorption support is arranged in the frame structure and is formed by welding two arch-shaped steel pipes in a crossed mode. The structure is simple and compact and installation is convenient and flexible. And secondly, the arch-shaped energy dissipation and shock absorption support has good energy dissipation performance, vibration input energy can be effectively consumed, and the dynamic response of the structure is reduced. Meanwhile, the device is made of low-yield-point steel and has high strain rate sensitivity and excellent fatigue performance. In addition, the arch-shaped energy dissipation and shock absorption support can be compatible with a conventional steel column and steel beam frame, special structural arrangement is not needed, and the actual use requirement of a building is better met. The problem that an existing energy dissipation and shock absorption device is complex in structure is solved.

The invention discloses a rock dynamic triaxial statistical damage constitutive model establishing method, and belongs to the technical field of rock dynamic constitutive model basic research of deep underground engineering. The method comprises the following steps: introducing a nonlinear Mohr-Coulomb and Hoek-Brown strength criterion, and deriving a nonlinear rock dynamic strength criterion considering a strain rate effect based on a rock dynamic strength and strain rate dependent strength criterion of a thermal activation and viscosity mechanism; constructing a rock infinitesimal strength measurement method capable of reflecting rock dynamic deformation characteristics, and establishing a rock dynamic triaxial statistical damage constitutive model; and carrying out sensitivity analysis on the rock dynamic triaxial statistical damage constitutive model. According to the method, the rock dynamic triaxial statistical damage constitutive model suitable for the high confining pressure and the high strain rate is effectively established, so that the nonlinear deformation process of the deep high confining pressure rock under the dynamic load effect is accurately simulated, and the method can be applied to the technical field of rock dynamic constitutive model basic research of deep underground engineering.

The invention provides a Hopkinson device strain test signal correction system and a working method thereof. The Hopkinson device strain test signal correction system comprises a sample connecting device, a Hopkinson device, a laser interference velocity measurement system and a processor, the sample connecting device is used for fixing a to-be-tested sample and is respectively connected with the Hopkinson incident bar and the transmission bar to load elastic waves on the to-be-tested sample; the Hopkinson device is used for generating high-strain-rate impact on a to-be-tested sample through the incident bar and the transmission bar; the laser interference velocity measurement system is used for collecting velocity signals at a first interface and a second interface of a to-be-tested sample in real time to obtain a first velocity and a second velocity; and the processor is used for obtaining the corrected strain, stress and strain rate of the to-be-tested sample based on the obtained first speed and second speed.

The application belongs to the field of laser advanced manufacturing technology, and particularly relates to a method for connecting flat holes by pulse laser impact, a device thereof and application. The method for connecting flat holes by pulse laser impact comprises the following steps: placing bottom die, lower layer plate with sandglass-shaped through hole, upper layer plate, absorbing layer and constraint layer in sequence from bottom to top; clamping and fixing each layer by using a workpiece clamping system; placing the sandglass-shaped through hole region at the center of the pulse laser spot; under the pressure of the pulse laser impact wave, the upper layer plate is plastically deformed at high strain rate and impacts the upper inclined surface of the sandglass-shaped through hole of the lower layer plate, so that high-speed shear deformation occurs, thereby generating a metallurgical welding effect; with the continuous deformation of the upper layer plate, when the upper layer plate flows into the cavity of the sandglass-shaped through hole, an interlocking structure with small upper part and large bottom part is formed between the upper layer plate and the lower inclined surface of the sandglass-shaped through hole of the lower layer plate, thereby generating a mechanical riveting effect; the method provided by the application is used for welding and riveting of thicker or larger-thickness-difference plates.

The invention provides a method for measuring the dynamic hardness of a material based on bullet impact indentation. The method comprises the following steps: carrying out decontamination and polishing treatment on the surface of a target material; measuring the elastic modulus of the to-be-measured area; the hard spherical projectile is launched to impact the to-be-measured area to form an impact pit, and the springback speed of the projectile is measured in situ; measuring geometric parameters of the impact pit; establishing a contact force model of the elastic unloading section impacted by the projectile; and with the springback speed and the geometric parameters of the pit as input, obtaining the maximum loading force through a contact force model, and finally calculating the dynamic hardness. The dynamic Myer hardness is calculated by measuring the bullet rebound speed and pit parameters through the bullet impact indentation test without depending on real-time data acquisition of a high-frequency force / displacement sensor, so that the problem of strain rate upper limit caused by hardware limitation in the traditional technology is solved, and the blank of dynamic Myer hardness measurement under the high strain rate is filled up.

The invention relates to a laser-driven high-strain-rate micro-nano impact indentation testing method, and belongs to the field of precision testing. The method comprises the following steps: (1) determining a laser shock position on the surface of an elastomer, and laying an absorption layer at a corresponding position; (2) a transparent restraint layer is laid on the surface of the absorption layer, and an impact component composed of a pressing head, an elastic body, the absorption layer and the restraint layer is constructed; (3) adjusting the position of an impact part to be positioned on a laser focus plane, and simultaneously ensuring that a laser spot, a pressure head and a to-be-impacted area of the sample are coaxial; (4) adjusting the position of the sample to enable the distance between the sample and the tip of the pressure head to be 0-1mm; and (5) adjusting parameters of the laser device and the high-speed camera, synchronously starting the laser device and the high-speed camera, carrying out laser-driven high-strain-rate micro-nano impact indentation test, shooting indentation and ejection processes of the indenter in real time, and measuring speed characteristics. The method is realized by integrating laser shock and an elastic deformation mechanism, and has a relatively high strain rate for testing under a micro scale.

The invention relates to the field of urban rail transit engineering and structural dynamics, and provides an interlayer and strain rate coupled subway tunnel lining dynamic mechanical property evaluation method and system, and the method comprises the following steps: 1, preparing an interlayer-containing cement-based cylindrical sample; step 2, applying strain rate loading, and collecting original data; step 3, reconstructing stress-strain response, and performing criterion of stress balance and constant strain rate; 4, acquiring the energy absorption rate, the dynamic compressive strength and the yield inflection point strain, and recording the failure form type; 5, establishing a statistical damage model and inverting model parameters; step 6, extracting an initial damage coefficient and a damage rate, and establishing an empirical regression formula; and step 7, constructing an evaluation index set, performing grading evaluation, and outputting material optimization and process suggestions. According to the scheme, the design, checking calculation and rapid evaluation capabilities of the subway tunnel lining under high strain rate working conditions such as impact or explosion are remarkably improved.

The invention discloses a deep-sea high-pressure multi-strain-rate load test device and an operation method, and relates to the technical field of deep-sea load tests.The deep-sea high-pressure multi-strain-rate load test device comprises a base, a containing structure used for containing a test piece is arranged on the base, and a low-strain-rate load loading device used for stretching the test piece is arranged on the base; a dynamic impact structure for performing high strain rate impact on a test piece is arranged on the base, a pressurizing device is arranged below the base, the pressurizing device is used for injecting water into the accommodating structure and pressurizing the accommodating structure, and the pressurizing device can inject water into the accommodating structure, so that the water pressure in the accommodating structure is increased, and the water pressure in the accommodating structure is increased to a deep sea high-pressure environment; the low-strain-rate load loading device can enable the test piece to be stretched in various low-strain-rate states, and the dynamic impact structure is matched to spread high-strain-rate impact to the test piece, so that the test piece can be subjected to a combined test in a deep sea environment.

The invention provides a device and a method for testing the composite stiffness of a biomass soft tissue. The device comprises a testing platform, the top of the weight is provided with a weight acceleration sensor; the drop hammer impact device comprises a hammer head, and an impact sensor is mounted at the bottom of the hammer head; the data acquisition system is connected with the weight acceleration sensor and the impact sensor; and the data processing system is connected with the data acquisition system and is used for calculating viscoelastic parameters of the biomass soft tissue sample according to the excitation load, time and response displacement data transmitted by the data acquisition system. According to the invention, impact loading with a high strain rate in an extremely short time is realized by using the drop hammer, a dynamic stress environment of soft tissue under a real physiological condition is simulated, loading of biological soft tissue can be realized by changing the release height of the drop hammer, and especially the viscoelastic behavior under a large deformation condition can be processed.

The invention provides a coal body strain synchronous in-situ monitoring device and method based on true triaxial impact, and relates to the field of coal body dynamic testing and structural damage monitoring. Comprising a sample bearing module, an impact loading module, an internal fiber bragg grating dynamic strain monitoring module, a surface strain gauge monitoring module, a synchronous data acquisition module, a microscopic crack detection module and a macroscopic failure analysis module, the impact loading module is used for applying a transient impact load with a set impact speed to the gas-solid coupling coal sample, and the internal fiber bragg grating dynamic strain monitoring module is embedded with at least one fiber bragg grating sensing grating point along three mutually orthogonal directions of the gas-solid coupling coal sample respectively. The damage evolution mechanism of the gas-solid coupling coal body under the high strain rate condition is disclosed, and a means is provided for risk analysis of the rock burst-coal and gas outburst hybrid power disaster.

The invention provides metal wire forming equipment for dish rack manufacturing, and relates to the technical field of metal wire drawing, the metal wire forming equipment comprises a rack, a guide mechanism, a lubricating mechanism, a winding drum drawing mechanism, a wire and a coating mechanism; the guide mechanism comprises a plurality of fixed wheels arranged on one side of the top of the rack through a rotating rod and a movable movable wheel located on the other side of the top of the rack, the fixed wheels and the movable wheels are arranged in a front-back staggered mode to form a wire channel, and the wire penetrates through the wire channel to rightwards enter the smearing mechanism. According to the scheme, when the wire rod is drawn, lubricating oil is adopted to lubricate the wire rod and the inner wall of the drawing die, the lubricating oil is in a liquid state and can form a continuous and stable lubricating film after covering the surface of the wire rod, direct contact between the wire rod and the drawing die is effectively isolated, the friction coefficient is reduced, and the service life of the wire rod is prolonged. And the lubricating oil can fill a microcosmic gap between the drawing die and a material in real time along with deformation of the wire rod, and is suitable for a high-strain-rate drawing process.

This invention discloses a load testing device and method for high strain rate tensile testing. The device includes an elastic rod (1), strain gauges (2), a tensile testing machine (3), a clamp connector (4), and a data acquisition unit (5). One end of the elastic rod is fixed to the lower crossbeam (31) of the tensile testing machine, and one end of the specimen (6) is connected to the other end of the elastic rod through the clamp connector. The other end of the specimen is fixed to the upper crossbeam (32) of the tensile testing machine. Several strain gauges are spaced apart on the elastic rod, and the output ends of the strain gauges are connected to the data acquisition unit. Each strain gauge independently transmits its stress signal to the data acquisition unit. This invention can obtain ideal and reliable dynamic mechanical property data by decomposing the transmission and superposition of stress waves during material tensile testing at high strain rates, reducing the oscillation effect of load signals, obtaining the true stress loaded on the sample, and improving the accuracy of test results.

The utility model discloses Hopkinson bar test equipment based on a rubber band transmitting device. The Hopkinson bar test equipment comprises a base, a platform, a clamp, a transmitting device, an incident bar, a transmission bar, an absorption bar and a damper, a plurality of bases are arranged at the bottom of the platform, and a launching device is arranged at the end of the upper side; the launching device comprises a shell, a bullet, a positioning pile and a rubber band; the bottom of the shell is fixed on the platform, a track is arranged in the shell, and stretching tracks are arranged on two sides; the bullet is positioned in the track and can translate along the track; handles are arranged on two sides of the bullet, are positioned in the stretching track and can translate along the stretching track; the positioning piles are fixed on the platform on the two sides of the launching device; the two ends of the rubber band are arranged on the two positioning piles in a sleeving mode respectively and penetrate through the track and the stretching track. According to the utility model, the mechanical property test cost of the material under the condition of high strain rate can be reduced, the stability and repeatability of the test are improved, and the test equipment is more compact and is convenient to transport, install and use.

The application relates to a kind of high strain rate under fiber concrete material dynamic axial tensile performance test method, comprising: setting Hopkinson tensile rod device, using the verified Hopkinson tensile rod device to pulse wave is applied to test piece, and the deformation of resistance strain gauge is collected;The deformation is converted into voltage signal, for calculating the strain of resistance strain gauge and the average compressive stress of test piece;Based on strain and average compressive stress, determine the dynamic tensile stress-strain relationship of test piece, according to the dynamic tensile stress-strain relationship of test piece, the dynamic tensile stress time history and dynamic axial strain time history are point by point corresponding pairing on time axis, and the dynamic tensile stress-strain curve of test piece under high strain rate is obtained.The application can make the performance test of fiber concrete and other materials under high strain rate more easily realized, provide the basis for the dynamic performance characterization of material, help the application and popularization of high-performance materials under extreme working conditions such as explosion impact.

The invention discloses a treatment process for improving the three-point bending fatigue limit of a thin-wall titanium alloy test piece, and relates to the field of metal material processing for improving the anti-fatigue performance, and the treatment process comprises the following steps: pretreating a TC4 titanium alloy sheet to obtain a test piece; processing the test piece by using ultrafast laser shock peening; setting a load, and respectively carrying out three-point fatigue tests on the test piece before and after strengthening; and calculating the bending fatigue limit of the test piece before and after strengthening, and carrying out strengthening mechanism analysis and comparison. According to the method, a thin-wall TC4 titanium alloy three-point bending test piece can be subjected to impact strengthening by optimizing the combination of femtosecond laser energy and impact times, a gradient structure and residual compressive stress are introduced to a surface layer by utilizing high-strain-rate plastic deformation induced by ultrafast laser, fatigue crack initiation is inhibited, meanwhile, expansion of a heat affected zone and deformation of the test piece are avoided, and the impact strength of the thin-wall TC4 titanium alloy three-point bending test piece is improved. Therefore, the bending fatigue performance is improved.

The application discloses a high-speed current-carrying strain experiment device, which comprises a base, a protection tube and an electric wire. The protection tube is horizontally arranged on the top of the base and fixedly installed at both ends of the base. The electric wire is arranged in the protection tube and extends along the axis of the protection tube. The electric wire is insulated from the protection tube and the base. The arc part of a test piece is used for sleeving the outer circumferential surface of the axial middle part of the protection tube. Insulating pads are arranged between two long plates. The two long plates are provided with conductive blocks, insulating blocks and jacks in sequence on the side away from the insulating pads. The jacks are screw-connected with the base and used for pressing the long plates on the insulating pads. The bottom ends of the two conductive blocks are arranged outside the base and form wiring ends for connecting a power supply, so that the test piece can carry current when being impacted by a shock wave. The experiment device solves the problems that the upper limit of the strain rate that can be applied to the test piece by the current experiment device is low and the material cannot carry current under high strain rate.

The invention relates to the technical field of Hopkinson bar experiments, in particular to a liquid filling device for Hopkinson bar experimental equipment, which comprises a liquid filling cylinder and a height-adjustable support seat, the liquid filling cylinder comprises a liquid filling ring with a liquid filling port, two axial sides of the liquid filling ring are respectively connected with a connecting pipe, the connecting pipe and the liquid filling ring are coaxial, and the height of the liquid filling ring is adjustable. The connecting pipe is of a conical reducing structure, the large-diameter end of the connecting pipe is detachably connected with the liquid filling ring, the small-diameter end of the connecting pipe clamps a rock sample, and a support used for supporting the rock sample is arranged in the liquid filling ring. A clamping connecting assembly used for applying clamping force to the small-caliber end of the connecting pipe and connecting the liquid filling barrel with the height-adjustable supporting seat is arranged outside the small-caliber end of the connecting pipe, and a hydraulic sensor is arranged in the liquid filling ring. In the high strain rate loading process of the Hopkinson bar experiment, stable, closed and controllable liquid filling can be performed on the internal fracture area of the sample, so that the dynamic response research on the water-containing fractured rock mass is realized.

The application discloses a cylindrical RM instability strength measurement experiment system and method, and belongs to the technical field of fluid mechanics. The cylindrical RM instability disturbance growth material strength measurement experiment system comprises an experiment device and a measurement system; the experiment device comprises a driving sleeve and a preset disturbance target, and the preset disturbance target is coaxially arranged in the driving sleeve. The cylindrical RM instability strength measurement experiment system and method provided by the application can precisely measure the disturbance growth speed, amplitude, interface morphology and other parameters when high-precision impact loading disturbance targets and filling media in the disturbance targets in the driving sleeve cylindrical implosion are carried out, the strength of the material is calculated by using fluid dynamics numerical simulation of different strength constitutive models or parameters and taking the experimentally measured disturbance data as convergence basis, and the established cylindrical RM instability disturbance growth material strength measurement experiment system and method have important significance for the strength research of materials under conditions of high pressure, high strain rate, large strain and the like.

The application discloses a treatment process for improving the three-point bending fatigue limit of a thin-walled titanium alloy test piece, relates to the field of improving fatigue resistance of metal material processing, and comprises the following steps: pretreating a TC4 titanium alloy sheet to obtain a test piece; performing laser shock peening on the test piece by using ultrafast laser; setting a load; performing three-point bending fatigue experiments on the test piece before and after the peening; calculating the bending fatigue limits of the test piece before and after the peening; and performing strengthening mechanism analysis and comparison. The process can perform peening on the three-point bending test piece of the thin-walled TC4 titanium alloy by optimizing the combination of femtosecond laser energy and peening times, introduce gradient structure and residual compressive stress in the surface layer by using the high strain rate plastic deformation induced by the ultrafast laser, inhibit the initiation of the fatigue cracks, avoid the expansion of the heat affected zone and the deformation of the test piece, and thus improve the bending fatigue performance of the test piece.

This application discloses a method, apparatus, and electronic device for predicting fracture strain in metallic materials. The method includes first determining the stress triaxiality and Lode angle of the metallic material under test based on the stress state at the test point; then constructing a stress fracture prediction model based on the correlation function between fracture strain and stress triaxiality and Lode angle; next, coupling this model with the Johnson-Cook fracture model to form a thermo-mechanical-strain rate coupled fracture prediction model; and finally, determining the target fracture strain based on this model. This approach not only overcomes the limitation of insufficient consideration of the Lode angle in existing fracture models but also achieves efficient model construction with very few parameters to be calibrated. The model is applicable to fracture prediction under complex stress, high temperature, and high strain rate multi-field coupling, significantly improving prediction accuracy while enhancing the model's engineering applicability and robustness, providing a reliable fracture assessment tool for cutting-edge engineering scenarios such as advanced manufacturing and extreme environment equipment design.

The invention relates to a method for testing a fracture track of a metal material under a multi-field coupling effect. The method comprises the steps of sample preparation, high-temperature speckle preparation, sample loading, strain field acquisition, fracture morphology observation, data processing and fracture model establishment. By constructing a new fracture test method under the action of multi-field coupling, the problems of lack of physical field coupling factors, non-uniform test systems, limitation of fracture models and the like at present are effectively solved. A coupling loading test system capable of synchronously applying complex stress, high strain rate and transient high temperature is established, and real simulation of the multi-physical field coupling effect under the actual disaster working condition is achieved; a metal material fracture test system with universality and comparability is formed; key data support is provided for building a fracture model comprehensively considering the stress three-dimensional degree, the strain rate effect and temperature softening, the accuracy and reliability of fracture track prediction of the steel structure under the extreme disaster are remarkably improved, and an important basis is provided for engineering disaster resistance design and safety evaluation.

The present application belongs to the technical field of energetic materials and active fragment materials, and more particularly relates to an energetic composite connector based on hard alloy and tungsten-containing amorphous alloy, a preparation method and application thereof. The penetration ability and damage effect of energetic materials are fully considered, and the present application selects hard alloy as the penetration part and tungsten-containing amorphous alloy composite material as the fragment part. The hard alloy has high hardness and high fracture toughness, and can effectively penetrate the shell; the amorphous alloy composite material has high strength, high energy density and good plastic deformation capacity, can deflagrate at a high strain rate and release a large amount of energy, and produce a large amount of fragments to cause damage to the target. The integration of the preparation and connection of the hard alloy penetration part and the amorphous alloy composite material fragment part can be realized by discharge plasma sintering, thereby solving the technical problems that the inert energetic materials in the prior art cause the personnel and weapon equipment to suffer losses due to "hitting but not destroying" the target.

This invention provides a metal wire forming device for manufacturing dish racks, relating to the field of metal wire drawing technology. It includes a frame, a guiding mechanism, a lubrication mechanism, a drum drawing mechanism, wire, and a coating mechanism. The guiding mechanism includes multiple fixed rollers mounted on one side of the top of the frame via rotating rods and movable rotating rollers on the other side. The fixed and rotating rollers are staggered to form a wire channel, through which the wire passes to the right and enters the coating mechanism. This solution ultimately achieves lubrication of the wire and the inner wall of the drawing die using lubricating oil during the wire drawing operation. The lubricating oil is liquid; after covering the wire surface, it forms a continuous and stable lubricating film, effectively isolating the wire from direct contact with the drawing die, reducing the coefficient of friction. Furthermore, the lubricating oil can fill the microscopic gaps between the drawing die and the material in real time as the wire deforms, adapting to high strain rate drawing processes.

The present invention provides a method for preparing a super-hydrophobic surface by ultrasonic rolling nanoparticles, which belongs to the technical field of metal hydrophobic surface preparation, comprising the steps of: pre-treating the alloy surface to make the surface roughness ≤0.5μm, performing ultrasonic cleaning, and drying; silanizing the nanoparticles, bonding the nanoparticles after the silanization treatment to the alloy surface using an adhesive; embossing the nanoparticles on the alloy surface using ultrasonic rolling; when embossing using ultrasonic rolling, the rolling head is radially pressed into the alloy surface, first rolling along a set path as a whole, and then rolling along a set path two to obtain a super-hydrophobic surface. The present invention realizes a one-step preparation of a hydrophobic texture through the high strain rate elastic-plastic deformation produced by ultrasonic rolling, while producing an ideal residual compressive stress on the surface of the part, and the material properties and texture strength are significantly improved, with higher reliability and mechanical stability.

The utility model provides an experimental device for testing the dynamic shearing mechanical property of a fiber monofilament interface. The experimental device comprises a loading part, a clamping part, a testing part and an adjusting part, the loading part comprises a sleeve bullet, a flange, an electromagnetic driving device and an absorbing device; the clamping part comprises an incident rod, a clamp, a single-axis displacement platform, a sample, a transmission rod, a first bracket and a second bracket; the testing part comprises a PDV speed measuring device, a support and a strain gauge; the adjusting part comprises a microscope, a connecting rod, a universal table base and a base. According to the utility model, dynamic shearing of materials is realized in a high-strain-rate state.

The invention belongs to the technical field of material science foundation, and discloses a single twinborn system dominated twinborn transmission probability prediction method. According to the method, aiming at the condition that a single twin system is started preferentially under specific texture and force field conditions, the uniqueness of the twin system is limited and activated, and a three-dimensional matrix expression system of specific twin system spatial orientation is constructed. And based on a judgment rule that twin crystal faces and twin directions of the two crystal grains are parallel, calculating the minimum orientation difference capable of realizing parallel twin systems among the crystal grains. According to the method, the twinborn orientation difference is provided as a key physical quantity for quantifying the twinborn transmission capability, and the regulation and control mechanism of single twinborn system activation on local stress redistribution is disclosed by eliminating the interference of a non-activated twinborn system. The method is applicable to a twin-dominated deformation system at low temperature or high strain rate, and provides a micromechanical basis for optimizing strain coordination at the grain boundary.

The invention provides a butt joint high-speed tensile property test device based on falling impact. The butt joint high-speed tensile property test device comprises a base, a support frame, an impact part, a clamping part and a data acquisition device, the two ends of the supporting frame are perpendicularly connected with the base. The clamping part is arranged on the base to clamp a sample with a required thickness; the impact part is movably arranged in the supporting frame and arranged above the clamping part, and the impact force of the impact part and the height of the impact part in the supporting frame can be adjusted so as to impact the clamping part; and the data acquisition device acquires test data. According to the invention, the actual stress condition of the butt joint can be truly simulated, the tensile test under different impact load effects is realized, the stability and accuracy of test data are ensured, the clamping part can clamp the samples with various thicknesses, the tensile test on the butt joint samples with different thicknesses under a high strain rate is realized, and the test efficiency is improved. And the high-speed tensile property of the butt joint structure can be evaluated, so that the welding quality of the butt joint is evaluated.

The present application relates to the field of urban rail transit engineering and structural dynamics, and provides a sandwich and strain rate coupled subway tunnel lining dynamic mechanical property evaluation method and system, the method comprising the following steps: step 1, preparing a cement-based cylindrical sample containing a sandwich; step 2, applying a strain rate loading and collecting original data; step 3, reconstructing the stress-strain response and performing stress balance and constant strain rate criteria; step 4, obtaining energy absorption rate, dynamic compressive strength and yield inflection point strain, and recording the failure mode type; step 5, establishing a statistical damage model and inverting the model parameters; step 6, extracting the initial damage coefficient and damage rate, and establishing an empirical regression formula; step 7, constructing an evaluation index set, performing a grading evaluation, and outputting material optimization and process recommendations. The present scheme significantly improves the design, checking and rapid evaluation capability of subway tunnel lining under high strain rate conditions such as impact or explosion.