36 results about "Macroscopic stress" patented technology

The invention relates to a red high-brightness elastic stress luminescent material and a preparation method thereof. The preparation method is characterized in that a red high-brightness elastic stress luminescent material (Ba, Ca) TiO3:Pr<3+>, Re<3+> (Re<3+> is one or more of Y<3+>, La<3+>, Nd<3+>, Gd<3+>, Yb<3+> and Lu<3+>) is prepared by taking a complex-phase (Ba, Ca) TiO3:Pr<3+> material as a matrix and using a method for co-doping one or more of trivalent rare earth ions Y<3+>, La<3+>, Nd<3+>, Gd<3+>, Yb<3+> and Lu<3+> and a trivalent rare earth ion activating agent Pr<3+>. The red high-brightness elastic stress luminescent material and the preparation method thereof have the advantages: (1) the preparation method of the material is simple, easy to operate and low in equipment requirement; (2) the prepared material (Ba, Ca) TiO3:Pr<3+>, Re<3+> is relatively strong in elastic stress luminescence, clear and macroscopic in elastic stress luminescence brightness at dark places, rapid in stress luminescence afterglow attenuation, free of macroscopic stress luminescence glows and stress tracks and capable of being widely applied to the fields such as real-time stress distribution detection, stress sensors, displays, entertainment devices and the like for living bodies, mechanical parts, buildings and the like; (3) the raw materials Ba, Ca and Ti of a material system are all rich elements on the earth and belong to environment-friendly materials.

The invention provides a preparation method and a structure of a three-dimensional memory. According to the preparation method and the structure, a contact hole technology of a peripheral circuit region is advanced to be prior to a metal gate technology of an array memory region, so that etching of a contact hole to release of silicon oxide film stress of the peripheral circuit region is realized,distribution of macroscopic stress of a wafer is improved, and bending is effectively reduced. In addition, the contact hole technology of the peripheral circuit region is arranged prior to the metalgate technology of the array memory region, so that nonuniformity of local stress of the metal gate technology of the array memory region cannot cause contact failure of a peripheral circuit. The preparation method and the structure are realized by the following technical schemes.

The invention aims to provide a TKD (transmission Kikuchi diffraction)-based determining method for stress state of a single grain of a polycrystalline material. The method is characterized by comprising the following steps: the to-be-studied single grain is determined firstly, whether dislocation density of the grain and several surrounding grains has order-of-magnitude difference is determined,if the density has order-of-magnitude difference, further analysis can be performed, and a slip system open in the grains is determined; then specific orientation distribution of the grains is obtained by adopting the TKD analysis technology; the slip system is input into a Schmid factor calculation part of an HKL Channel 5 system, the macroscopic stress direction is adjusted simultaneously, an obtained Schmid factor value is enabled to be consistent with a predicted result, then the macroscopic force is the stress direction of the grains and is also the stress direction of the single grain. The method is applicable to any crystalline material, the specific stress state of the single grain in the material in a deformation process can be calculated well, and one definite and effective method is provided for studying the microscopic deformation mechanism of the polycrystalline material.

The invention provides a testing method for microscopic deformation of a material. The method employs a combination of symmetric diffraction experiments and dual-channel acoustic detection to test information about evolution of a microstructure in a sample in the whole stress loading process and realizes direct in-situ nondestructive measurement of inner static and dynamic microscopic deformation information of a block material. According to the method, a corresponding measurement crystal face is selected according to the crystal structure of the sample; and in a geometric layout that a radiation source and a detector are symmetrically arranged at two sides of a stress loading device, static microscopic deformation information including interplanar spacing, oriented direction and the like in different stress loading phases are measured by using diffraction experiments, and dynamic microscopic deformation like twin crystal nucleation and dislocation movement in the process of stress loading are continuously measured by using a dual-channel acoustic probe. The testing method for the microscopic deformation of the material is applicable to monitoring and analysis of inner microscopic mechanism and process of metal alloy materials in the process of macroscopic stress loading and to testing of characteristic deformation information like fracture failure of non-metal alloy materials.

The invention relates to a turbine mortise shot blasting discrete element-finite element coupling multi-scale simulation method which comprises the following steps: (1) cutting a mortise structure tobe researched according to the symmetry of the mortise structure, and endowing a constitutive model with a high strain rate; (2) setting the relative positions of a nozzle and the mortise according tothe actual process condition, defining the size and angle of the nozzle, and completing the modeling of the mortise and the nozzle; (3) acquiring dislocation evolution model parameters based on the stress-strain data under the high strain rate, establishing a dislocation evolution model of the mortise material, and associating the grain size, the dislocation density and the macroscopic stress-strain; (4) defining a particle generator * Particle by using a DEM module, setting bullet parameters, combining the mortise with the nozzle, and setting contact characteristics between pellets and the mortise; and (5) carrying out numerical simulation, and obtaining surface integrity parameters after mortise structure strengthening.

The invention relates to a high-energy shot blasting surface hardness numerical simulation method which comprises the following steps: (1) acquiring dislocation evolution model parameters based on stress-strain data under a high strain rate, establishing a dislocation evolution model of a to-be-studied material, and associating grain size, dislocation density and macroscopic stress-strain; (2) acquiring strength model parameters, establishing a strength model of the to-be-researched material, and associating the strength with the grain size; (3) acquiring parameters in the strength and hardness relationship based on the test data, establishing the strength and hardness relationship of the to-be-researched material, and associating the surface hardness with the strength; (4) conducting programming by using a VUSDFLD subprogram of ABAQUS finite element software, and establishing a relationship between the surface hardness and macroscopic parameters based on the relationship among the dislocation evolution model, the strength model and the strength and hardness to complete programming; and (5) conducting shot peening strengthening numerical simulation based on ABAQUS software, and obtaining surface hardness distribution after strengthening.

The invention provides a heterostructure simulation method based on ABAQUS. The heterostructure simulation method comprises the following steps: establishing a 2D representative volume unit of a uniform structure and a heterostructure; correcting the sliding resistance model and the back stress model and writing the sliding resistance model and the back stress model into a user subprogram UMAT soas to define an elastic-plastic constitutive equation of the crystal; determining material parameters in the UMAT by utilizing the stretching curves of the three different structures; applying a periodic boundary condition and an external load, and calculating a stress-strain response of each crystal grain by utilizing ABAQUS; averaging stress and strain of all crystal grains; changing parameterssuch as microstructure and grain orientation of the model, predicting and analyzing corresponding macroscopic stress-strain response, strengthening effect and microcosmic deformation cloud atlas, andcomparing to obtain the optimal microstructure. According to the heterostructure simulation method, the grain size effect and extra back stress strengthening of the heterostructure are considered, theheterostructure can be simulated, and the heterostructure simulation method has the advantages of being visual, high in applicability and high in accuracy.

The invention discloses a prediction method for microstructure evolution of a shot peening strengthening material. The prediction method comprises the following steps: 1, establishing a three-dimensional shot peening model by using an ABAQUS platform; 2, embedding a constitutive equation based on dislocation density evolution into the shot peening strengthening three-dimensional model; 3, measuring the radius of the crater; 4, calculating the number of shots required in a unit area when the shot blasting coverage rate reaches a set value; 5, establishing a shot peening strengthening three-dimensional model with multiple randomly distributed shots; and 6, analyzing the process that the projectile flow impacts the target body by using an ABAQUS/Express solver, and calculating to obtain the dislocation cell size and the dislocation density distribution. The method has the technical effects that under the condition of considering the relationship between the macroscopic stress-strain fieldand the microstructure of the material, the evolution data of the microstructure of the material by different shot peening strengthening parameters is obtained, the understanding of shot peening process parameters is deepened, the shot peening process parameters are optimized, and the shot peening strengthening treatment effect is improved.

The invention discloses a nondestructive testing method for residual stress at different depths in a thermal barrier coating, and the method is used for carrying out nondestructive detection on the residual stress at different depths in the thermal barrier coating of an aero-engine by adopting an X-ray diffraction instrument. The method comprises the following steps of firstly, placing and fixinga thermal barrier coating test piece on a sample table, enabling a normal direction of a sample to be consistent with a normal direction of an incident ray, setting the scanning range, adjusting the power of a ceramic X-ray tube, the frequency of the X-ray, the reproducibility of an angular instrument, the controllable minimum step, the maximum counting rate of a PIXcel3D super-energy detector, the sample table direction correction and other factors, emitting the X-ray with the specific frequency, and determining the residual stress at different depths in the thermal barrier coating on the basis of a relation between the displacement of an X-ray diffraction peak and the macroscopic stress. According to the nondestructive testing method for the residual stress in the thermal barrier coatinghas high measurement precision and efficiency and good reproducibility, and is widely applied to nondestructive detection of the residual stress of the thermal barrier coating of the aero-engine.

Disclosed is a method of making a timepiece spring from monocrystalline material including the following steps: drawing the spring; identifying one or more zones of weakness of the spring in which or in at least one of which the spring will break in the event of excessive deformation; manufacturing the spring from a wafer of monocrystalline material extending in a determined plane, while orienting the spring in the wafer such that the direction of the macroscopic stresses in the or each zone of weakness when the spring is deformed is substantially parallel to a plane of cleavage of the material intersecting the determined plane. Also disclosed is a timepiece spring obtained by such a method.

The invention relates to a particle system macroscopic stress fluctuation prediction method based on a convolutional neural network, and the method comprises the following steps: converting the microcosmic plastic deformation of a particle system into a regular three-dimensional voxel matrix based on the microcosmic plastic behavior of particles and a coarse graining method of a Gaussian kernel function; establishing a deep learning data set which takes the three-dimensional voxel matrix as input and takes actual macroscopic stress fluctuation of the particle system as output; and training a convolutional neural network based on the deep learning data set, and establishing a cross-scale prediction model of the quantitative relationship between the microscopic behavior and the macroscopic response of the particle system. According to the particle system macroscopic stress fluctuation prediction method based on the convolutional neural network, the quantitative relation of the particle system from the particle microcosmic plastic behavior to the macroscopic mechanical response can be established, and a brand-new and effective way is provided for macroscopic stress fluctuation prediction and macroscopic and microcosmic cross-scale research of particulate matter.

The invention discloses a fatigue microcrack propagation prediction method based on EBSD characterization and crystal plasticity. The fatigue microcrack propagation prediction method comprises the following steps: acquiring a stress-strain hysteresis loop; compiling a macroscopic viscoplastic constitutive model, and determining parameters of the macroscopic viscoplastic constitutive model; establishing a finite element model of the macroscopic component, endowing the finite element model with viscoplastic constitutive material parameters, carrying out fatigue loading to obtain a macroscopic stress field and a displacement field of the component, and preliminarily determining a dangerous part of the component; compiling a crystal plastic constitutive model, and determining parameters of the model; establishing a local mesoscopic model; dangerous crystal grains are determined; initial cracks are introduced, and the initiation life is determined through a crack initiation model; the accumulated strain energy dissipation density distribution of the cracked crystal grains and the adjacent crystal grains is judged at the tip of the crack, the end point of the initial crack serves as the starting point, and a new crystal penetrating crack continues to be introduced into the slippage system with the maximum accumulated strain energy dissipation density; and determining the microcrack propagation life. The method can consider the influence of the microstructure features of local grains on the crack propagation behavior.