762 results about "Poisson's ratio" patented technology

The invention provides a macroscopic finite element simulation analysis method and device for a sealing element considering plastic deformation, and belongs to the field of sealing element design. The method comprises the following steps: acquiring an engineering stress-strain curve of a plastic material in a compression state; converting the engineering stress-strain curve into a real stress-strain curve; determining a yield limit, and taking a strain point corresponding to the yield limit as a demarcation point of elasticity and plastic deformation; an elastic section of a real stress-strain curve is extracted, the elastic modulus is calculated, and the Poisson's ratio is obtained through axial and transverse strain measurement in a uniaxial compression test; a true stress-strain curve plastic section is extracted, and a multi-linear isotropic hardening model is established; constructing a complete elastic-plastic constitutive model covering the elastic deformation area and the plastic deformation area; the stress distribution, the strain response and the contact performance of the plastic sealing element in a compression deformation state are simulated. According to the method and the device provided by the invention, the problem that the result does not conform to the reality due to the fact that only elastic modulus and Poisson's ratio are used in existing sealing element simulation can be solved.

The invention relates to the field of geological exploration and geotechnical engineering, provides a rock mass dynamic mechanical parameter sensing method and system based on while-drilling parameters in order to dynamically obtain rock mass dynamic mechanical parameter characteristics in situ in real time in the drilling process, and provides a rock mass dynamic mechanical parameter sensing method and system based on while-drilling parameters by using multi-modal signals such as vibration, acoustic emission, torque and bit pressure through uniform characteristic engineering and multi-task learning. The instantaneous elastic modulus, the dynamic Poisson's ratio, the transient uniaxial compressive strength, the cohesive force and the internal friction angle can be synchronously and dynamically predicted in single drilling, and the limitation that only a single static parameter is estimated in a traditional method is broken through; a rock mass dynamic mechanical parameter acquisition model constructed on the basis of a multi-modal adaptive graph attention sequential network can effectively couple the physical proximity and the statistical association relationship of a sensor, and integrates expansion sequential convolution and a time perception Transform module, so that the characterization capability of emergencies (such as jamming / friction resistance) and long-term trends is considered on the premise of low time delay; therefore, the prediction accuracy is improved.

The invention discloses a breakable rock-soil granular material triaxial test simulation method based on a lattice spring-discrete element coupling framework, which comprises the following steps: establishing a triaxial test model rectangular boundary condition, and generating a non-breakable spherical rock-soil granular material in the boundary; replacing the generated non-crushable spherical particle material with rock-soil particles considering particle crushing based on a lattice spring-discrete element coupling frame, and assigning parameters; replacing wall bodies on the two sides of the rectangular boundary condition with a large number of bonded spherical particles to generate a flexible membrane boundary; and applying confining pressure to the boundary of the generated flexible membrane, and carrying out shear simulation. According to the method, the Young modulus and the Poisson's ratio can be matched in a high-precision mode, the heterogeneity of elastic response is reduced, strength degradation and friction characteristics are simulated, and the calculation efficiency is greatly improved.

The invention relates to a negative Poisson's ratio metamaterial cell element structure based on a three-rod tension structure, which belongs to the field of mechanical metamaterials and comprises a three-rod tension integral structure component and a degree-of-freedom constraint component. Under the action of a three-rod nine-cable tension integral structure, when the structure is not subjected to external load, the structure is subjected to interaction of internal stress, and the balance is achieved in a self-stabilization state; and under the state of external load, the upper surface and the lower surface can generate a torsion effect, and the structure can recover to the initial state after the external load is removed again. The negative Poisson's ratio metamaterial cell element structure based on the three-rod tension structure has the advantages of self-adaptability, self-recovery, compression-torsion characteristic and the like. The tensegrity structure and the mechanical metamaterial structure are combined, the types of existing mechanical metamaterial cell element structures are enriched, and a brand new direction is opened up for design, analysis and application of the tensegrity mechanical metamaterial structure.

The invention relates to the technical field of crustal stress measurement, in particular to a rock core three-dimensional crustal stress measurement system and method based on multi-source data. The method comprises the following steps: acquiring well wall damage information, and identifying a damage type in the well wall damage information; multiple sections of core samples are selected based on the well wall damage information, and overburden pressure parameters are determined based on the multiple sections of core samples; a rock mechanics experiment is conducted on the rock core sample, rock mechanics parameters are generated, and the rock mechanics parameters comprise the Poisson's ratio, the Young modulus, the uniaxial compressive strength value and the tensile strength value. According to the method, the difference value of the maximum stress and the minimum stress is combined with the multi-source coupling constraint principal stress interval, the intersection points are identified through the topological visualization graph, the numerical range of the maximum principal stress and the minimum principal stress can be accurately determined, and then the information of the three-dimensional crustal stress is obtained.

The invention discloses a molecular dynamics-macroscopic multi-scale coupling calculation method, which relates to the field of material damage numerical simulation analysis, and comprises the following steps: respectively establishing a microcosmic plate model and a macroscopic plate model; young modulus and Poisson's ratio parameters are calculated through microscale pneumatic simulation in the microcosmic plate model and are transmitted into the macroscopic plate model, a stress value I and a strain value I are obtained through macroscopic pneumatic simulation calculation and are transmitted into the microcosmic plate model, and the stress value I and the strain value I are obtained through microcosmic-macroscopic continuous coupling iteration. And obtaining the mechanical property indexes of the silicon thin plate in each stage from stress starting, crack generation, crack propagation to failure and fracture. The invention provides a molecular dynamics-macroscopic multi-scale coupling calculation method. A new analysis method is provided for researching structural failure and damage in an aerodynamic hot extreme environment through coupling calculation of macroscopic and microscopic scale models.

The invention belongs to the field of lattice structure design, and particularly discloses a continuous fiber reinforced composite material strength Poisson's ratio adjustable design method and system.The design method comprises the steps that the Poisson's ratio structure type needed by a continuous fiber reinforced composite material component to be prepared is determined, the Poisson's ratio structure type comprises a zero Poisson's ratio structure, a positive Poisson's ratio structure or a negative Poisson's ratio structure; according to the method, regular hexagonal unit cell models and hourglass-shaped hexagonal unit cell models are constructed, and according to the Poisson's ratio structure type, a plurality of regular hexagonal unit cell models and / or a plurality of hourglass-shaped hexagonal unit cells are utilized to construct a corresponding honeycomb porous structure model, so that the Poisson's ratio adjustable design of the continuous fiber reinforced composite material is realized. By means of the method, standardized design of material structures of high-strength, light-weight, vibration-reducing and energy-absorbing parts needed by various parts in different application fields can be achieved.

The invention relates to a negative Poisson's ratio metamaterial cell element structure based on a four-rod tension structure, which belongs to the field of mechanical metamaterials and comprises a four-rod tension integral structure component and a degree-of-freedom constraint component. Under the action of a four-rod twelve-cable tensioning integral structure, when the structure is not subjected to external load, the structure is balanced in a self-stabilizing state under the interaction of internal stress; and under the state of external load, the upper surface and the lower surface can generate a torsion effect, and the structure can recover to the initial state after the external load is removed again. The negative Poisson's ratio metamaterial cell element structure based on the four-rod tension structure has the advantages of self-adaptability, self-recovery, compression-torsion characteristic and the like. The tensegrity structure and the mechanical metamaterial structure are combined, the types of existing mechanical metamaterial cell element structures are enriched, and a brand new direction is opened up for design, analysis and application of the tensegrity mechanical metamaterial structure.

The invention discloses an energy-absorbing reinforced honeycomb structure with the Poisson's ratio capable of being adjusted positively and negatively and a design method, and relates to the field of honeycomb structures. Two horizontal outer ribs and four inclined outer ribs of the honeycomb structure form a hexagon; the two ends of the first arc-shaped inner rib are connected with the left upper vertex and the left lower vertex of the hexagon and are concave towards the left vertex of the hexagon; the second arc-shaped inner rib is connected with the right upper vertex and the right lower vertex of the hexagon and is concave towards the right vertex of the hexagon; two ends of one horizontal inner rib are respectively connected with the left vertex of the hexagon and the first arc-shaped inner rib, and two ends of the other horizontal inner rib are respectively connected with the right vertex of the hexagon and the second arc-shaped inner rib; and the circular ring is embedded in the convex parts of the two arc-shaped inner ribs. According to the honeycomb structure, the positive Poisson's ratio honeycomb and the negative Poisson's ratio honeycomb are fused through the two horizontal inner ribs, so that the inner ribs and the outer ribs are mutually balanced, the circular ring design is added, and the structural strength is improved; through the thickness parameter design of the inner ribs and the outer ribs, flexible transformation of the positive Poisson's ratio or the negative Poisson's ratio is achieved on the premise that light weight and high strength are guaranteed.

The invention discloses a concrete time-varying Poisson's ratio testing method. The method comprises the following steps: placing concrete in a preset concrete creep measuring device; after multi-axial pressure is applied to the concrete, creep data of the concrete in the pressed direction, stress data and strain data of the concrete in other directions and concrete test parameters are obtained; calculating a creep coefficient corresponding to the concrete based on the concrete test parameters; calculating the time-varying elastic modulus of the concrete in the multi-axis state based on the creep coefficient and the creep data; and calculating the time-varying Poisson's ratio corresponding to the concrete based on the time-varying elastic modulus, the creep data, the stress data and the strain data. According to the improved concrete creep measurement device and method, the Poisson's ratio of the concrete in the multi-axis stress state can be more accurately tested, the precision of the test result is improved, a research method about the change of the Poisson's ratio of the concrete along with time under the multi-axis stress is provided, and the application prospect is wide. Therefore, the safety and durability of the concrete structure are effectively guaranteed.

The invention relates to a modeling, designing and optimizing method for a three-dimensional annular buffering and energy-absorbing lattice structure based on additive manufacturing, and belongs to the field of lattice structure modeling, designing and optimizing. The purpose is to improve the light weight and impact resistance and energy absorption capacity of structural equipment. The method integrates the advantages of a negative Poisson's ratio lattice unit cell structure and an additive manufacturing technology, and comprises the following specific implementation steps of innovative three-dimensional lattice unit cell design, key geometric parameter definition, finite element analysis model preparation, convergence verification, parameter analysis and performance evaluation, training set construction, mapping model establishment and multi-objective optimization. The method has the remarkable advantages that the constraint of the additive manufacturing process is considered, the buffer energy absorption performance is remarkably optimized, and beneficial guidance and reference can be provided for related engineering practice.

Embodiments of the present invention relate to the technical field of shale gas development, and provide a method and system for predicting the maximum horizontal principal stress of shale gas reservoirs. The method comprises: performing cross-arranged gather extraction on acquired original shot gathers to obtain corresponding OVT gathers, and preprocessing the OVT gathers; acquiring well logging data, performing well-to-seismic calibration and seismic horizon interpretation on the basis of the well logging data, and obtaining an interpreted horizon of the current reservoir that meets in-situ stress prediction as a target horizon; constructing a low-frequency model on the basis of the well logging data and the target horizon, and calculating a Poisson's ratio and a fracture density on the basis of the low-frequency model; calculating a vertical principal stress of the target horizon on the basis of a velocity field, a formation density and a density inversion body; and calculating the maximum horizontal principal stress of the current reservoir on the basis of the Poisson's ratio, the fracture density, the vertical principal stress and a preset principal stress solving model. The solution of the present invention solves the problem of low accuracy in existing solutions for predicting the maximum horizontal principal stress of shale gas reservoirs.

The invention relates to the technical field of structures, in particular to a cubic double-pole ligament negative Poisson's ratio honeycomb lattice structure which comprises a plurality of honeycomb unit cells which are assembled in a linkage mode. Each honeycomb unit cell comprises two straight edges which are symmetrically arranged, the two ends of each straight edge are respectively connected with a cubic double-pole ligament, the four cubic double-pole ligaments are respectively symmetrical, the opposite ends of the two cubic double-pole ligaments on the same side are connected to linkage edges, and the two linkage edges are symmetrical to each other and are located on the same plane; the two straight edges, the four cubic double-pole ligaments and the two linkage edges form a linkage structure which is connected with each other. The invention aims to provide a cubic double-pole ligament negative Poisson's ratio honeycomb lattice structure, an oblique straight ligament of a traditional concave hexagonal unit cell is modified into a cubic double-pole curve ligament, and the optimization potential of energy absorption and impact resistance is enhanced.

The invention relates to the field of roadway surrounding rock supporting in underground engineering, in particular to a roadway negative Poisson's ratio gradient energy-absorbing supporting device which comprises a negative Poisson's ratio gradient energy-absorbing structure, compared with a conventional chiral negative Poisson's ratio structure, deformation regularity and controllability are enhanced, the shape of a connecting rod piece is changed in combination with the special working condition of a coal mine, and the supporting effect of the roadway negative Poisson's ratio gradient energy-absorbing supporting device is improved. The connecting rod piece is a double-spiral connecting rod piece; compared with a traditional hexagonal honeycomb structure, the defect that the honeycomb structure is too fast in failure after being pressed is overcome; and meanwhile, the concave deformation advantage and the chiral ring node rigidity advantage are combined. Gradient design can be adopted in a two-dimensional structure and a three-dimensional structure, through non-uniform distribution of spatial parameters, the bottleneck of a traditional structure in energy absorption efficiency and environmental adaptability is broken through, the structure is particularly suitable for a non-uniform load scene of coal mine underground engineering, the strength of a certain area can be intensively enhanced, the deformation mode of the structure can be changed, and the energy absorption efficiency is improved. And the structure can be customized according to different application scene requirements.

The invention discloses a multi-wave chromatography and reflection combined detection method and device for a thin-covering-layer urban active fault and a medium. The method comprises the steps that longitudinal wave seismic data and transverse wave seismic data are collected; recording vertical component data based on the longitudinal wave seismic data for first arrival travel time pickup and tomography inversion to obtain a longitudinal wave velocity structure model Vp; extracting Rayleigh surface wave frequency dispersion through the vertical component data and carrying out multichannel surface wave analysis inversion to obtain a transverse wave velocity structure model Vs; calculating a longitudinal and transverse wave velocity ratio parameter structure model Vp / Vs, and calculating to obtain a Poisson's ratio parameter structure model v; obtaining a longitudinal wave (P wave) reflection profile and a transverse wave (S wave) reflection profile; identifying and summarizing into an interpretation fracture set Fc, and recording key elements; and by taking the interpretation fracture set Fc as a structural skeleton, completing unified registration and superposition display on Vp, Vs, Vp / Vs and v, a longitudinal wave reflection profile and a transverse wave reflection profile, and outputting a shallow underground structure comprehensive interpretation map of the thin covering layer region.

The invention discloses a slope instability whole process calculation method, system and equipment based on a particle method. The method is based on a smoothed particle hydrodynamics (SPH) particle calculation method, combines a Riemannian large deformation theory, and realizes landslide simulation under a regional scale through a C + + / CUDA writing program. According to the method, the whole process of generation, connection, starting and accumulation of the sliding surface can be truly represented, the influence mechanism of rock and earth mass properties such as an internal friction angle, cohesion, particle size, elasticity modulus and Poisson's ratio on the landslide process can be analyzed, meanwhile, through a parallel heterogeneous CPU / GPU programming architecture, the calculation efficiency is improved by nearly a hundreds of times compared with the traditional CPU programming efficiency, and the calculation cost is greatly reduced. The watershed scale landslide flow velocity and accumulation range prediction is realized, the adaptability is very high, the defect that discrete element and finite element methods are limited by simulation scale and calculation efficiency is overcome, and a new thought is provided for large-scale landslide disaster prediction.

The invention discloses a plane matrix type high folding and unfolding bionic antenna truss structure with a negative Poisson's ratio effect, and relates to the technical field of space folding and unfolding mechanisms, the plane matrix type high folding and unfolding bionic antenna truss structure comprises a plurality of cell elements and a plurality of cell element connecting rods, transverse cell elements are connected through the cell element connecting rods, and longitudinal cell elements are fixedly connected through adjacent cell element cross beams; the cell element connecting rods are hinged to the cell elements on the two sides respectively, and the cell elements are three-level positioning inwards-concave hexagonal cell elements; the folding and unfolding antenna truss structure is in a folded state during launching, transportation and silent latency and is in an unfolded working state during on-orbit task execution, the high folding and unfolding ratio characteristic of the antenna provides bionic improvement inspiration for various urgent properties such as stealth and size reduction of a satellite antenna structure, the shape of the antenna folding and unfolding array can be changed in a multi-stage mode, and the antenna folding and unfolding array is suitable for large-scale popularization and application. Therefore, the functions of optimal frequency band adjustment, optimal area expansion, switching of different scanning ranges and the like are realized.

The invention relates to the technical field of mechanical metamaterials, in particular to a negative Poisson's ratio cell element with an embedded symmetrical broken subcell structure, which comprises a concave hexagonal main body, the concave hexagonal main body comprises two horizontal cell walls and inclined cell walls arranged at two ends of the two horizontal cell walls, and the central points of the two inclined cell walls are bent towards one side close to the central points of the horizontal cell walls; the number of the bent wall rods is two, and the two bent wall rods are symmetrically arranged in the inwards-concave hexagonal body. The inherent contradiction that the stretching performance must be sacrificed when the rigidity of a traditional concave honeycomb structure is improved is successfully solved, and the negative Poisson's ratio effect and the energy absorption capacity of the structure can be further improved while the structural rigidity is enhanced.

The invention discloses a self-adaptive impact-resistant protective metamaterial with a Poisson's ratio autonomous constraint function, which comprises a PMP honeycomb, the PMP honeycomb comprises a plurality of honeycomb unit cell structures, and each honeycomb unit cell structure comprises a hexagonal thin-wall structure I and a hexagonal thin-wall structure II internally connected in the hexagonal thin-wall structure I. The invention further discloses a preparation method of the self-adaptive impact-resistant protective metamaterial with the Poisson's ratio autonomous constraint function. Compared with an SHC honeycomb, the PMP honeycomb has the advantages that the dynamic Poisson ratio of the PMP honeycomb is relatively stable in the whole crushing process, and the initial fluctuation range is only 0.1. In addition, the average dynamic Poisson's ratio of the PMP honeycomb is relatively small, indicating that the PMP honeycomb is almost free of transverse deformation without additional assistance. After the PMP honeycomb is compressed to be densified, the transverse length of the PMP honeycomb is only increased by 3.5%. Wherein the PMP honeycomb has better self-constraint capability, so that the PMP honeycomb has a more stable energy absorption mode.

The invention discloses a sandwich structure based on chiral pressure torsion and negative poisson ratio honeycomb compounding, and relates to the technical field of mechanical metamaterials. The sandwich structure comprises an upper skin layer, a core layer and a lower skin layer, the core layer is formed by alternately compounding three-dimensional chiral compression-torsion cell elements and negative poisson ratio honeycomb cell elements which are periodically arranged, and the chiral compression-torsion cell elements form a bidirectional torsion stress network through spiral connecting rods; the negative Poisson's ratio honeycomb cell element is of a concave polyhedron structure and is nested with a butterfly-like substructure, and energy is absorbed through transverse contraction and folding deformation in a cooperative mode. The sandwich structure has a multi-stage energy dissipation mechanism: the chiral compression-torsion unit disperses impact energy through spiral deformation, the butterfly-like substructure elastically shrinks at low strain and slides and folds at high strain, and the energy absorption efficiency is enhanced through friction and plastic deformation; the structural parameters can be subjected to gradient regulation and control according to the impact strength, the lightweight rate and the deformation mode, and high design flexibility and working condition adaptability are achieved.

The invention discloses a fabric tensile strain visual intelligent detection method. The method comprises the following steps: (1) acquiring a fabric tensile video; (2) video sequence frame preprocessing: performing batch processing on the acquired fabric stretching video, performing image extraction according to a time sequence, and preprocessing a video sequence frame image; (3) deformation characteristic index extraction and calculation, including real-time characteristic point extraction and matching and deformation calculation, to obtain elongation, narrowest shrinkage and Poisson's ratio; (4) improving an image correlation analysis algorithm; according to the innovative detection method provided by the invention, an advanced machine vision technology and image correlation analysis are fused, and a fabric performance visual detection module is improved. Deformation of the fabric in the stress stretching process is monitored in real time, microscopic strain characteristics are accurately captured, and comprehensive evaluation of the fabric performance is achieved. By automatically calculating the morphological characteristic index and Poisson's ratio of the fabric and visualizing the in-plane strain distribution, the detection efficiency and precision are greatly improved.

The invention discloses a meshless EFGM and style migration-based multi-material structure topological optimization method, which comprises the following steps of: (1) inputting material attributes such as Young modulus, shear modulus and Poisson's ratio of a structure, and discretizing a design domain by using meshless nodes; (2) transforming the designed meshless density field to obtain a physical density field, and performing length scale filtering; (3) an alternating active phase algorithm is executed, and the displacement field, the system flexibility and the related sensitivity of the structure are solved based on the meshless EFGM; (4) executing a neural style migration program to calculate the difference between the current topological structure and the reference style image, and calculating the derivative of the physical density field of the topological structure to the network parameter; and (5) updating a design variable by using a moving asymptote algorithm, and judging whether an optimization loop is converged or not. According to the method, based on meshless EFGM and style migration multi-material structure topological optimization, topological structures with different artistic styles can be designed, and the method has engineering application value.

The invention provides an intelligent prediction method and system for settlement of a TBM penetrating through a pebble stratum, and belongs to the technical field of stratum settlement prediction. The method comprises the following steps: acquiring ground surface monitoring point position information, excavation surface position information and burial depth, inputting the information into a first deep neural network model, and acquiring and outputting tunnel vault displacement, haunch convergence and ground surface settlement; the second deep neural network model takes a position coordinate formed by earth surface monitoring point position information, excavation surface position information and burial depth and earth surface settlement as input, and outputs earth surface elastic modulus and Poisson ratio; obtaining stress-strain components of ground surface settlement, and constructing a control equation and boundary conditions based on the stress-strain components, the elastic modulus and the Poisson's ratio; obtaining prior geological information by using the residual error of the control equation; and by taking the control equation, the boundary condition and the prior geological information as constraint conditions, obtaining a settlement prediction value when the TBM passes through the pebble stratum based on the tunnel vault displacement, and realizing accurate prediction of the settlement of the pebble stratum.

The invention relates to the technical field of tire simulation design, in particular to a method, system and equipment for calculating contribution of tire parts to camber rigidity and a storage medium. The method is based on a finite element model and comprises the following steps: firstly, carrying out two-dimensional axial symmetry modeling and inflation analysis on a tire, rotating to generate a three-dimensional model, then establishing contact with a rigid road surface, applying rated inflation pressure and load, and carrying out steady-state rolling and camber working condition simulation to obtain reference camber rigidity comprising all parts; and then target parts such as a tread, a belted layer and sidewall rubber are selected, the Young modulus of the target parts is reduced to 0.01%-5% of a design value, the analysis is repeated on the premise that the Poisson's ratio of the target parts and other parts and boundary conditions are kept unchanged, and the camber rigidity of the target parts after degradation is obtained. The camber rigidity contribution value and contribution rate of the camber rigidity are calculated by comparing the difference value of the camber rigidity of the two working conditions and combining the occurrence frequency of the target component in the tire structure, and quantitative stripping of the camber rigidity influence of each component is achieved. According to the method, the component-level contribution spectrum can be quickly obtained on the premise of controllable errors, and an effective basis is provided for directional optimization design of the tire camber rigidity performance.

The invention discloses a nuclear power station in-service equipment physical performance monitoring method based on EMAT, and belongs to the field of nuclear power station equipment service performance detection. The method comprises the following steps: simultaneously exciting ultrasonic transverse and longitudinal waves by using an EMAT probe; the EMAT sensor is designed to resist high temperature; ultrasonic sound velocity correction in a high-temperature environment; key physical performance parameters such as elastic modulus and Poisson's ratio of in-service equipment in a high-temperature environment are continuously monitored by utilizing sound velocity data of transverse waves and longitudinal waves excited by an EMAT probe. Based on the electromagnetic ultrasonic principle, the method can effectively monitor the elasticity modulus, Poisson's ratio and other key physical performance parameters of the in-service equipment of the nuclear power station at high temperature, corrects the measurement error caused by high temperature, provides an important basis for the health management of the equipment of the nuclear power station, and ensures the feasibility and safety of the equipment.

The invention relates to a brittleness index calculation method and device for a superior paleozoic mud shale stratum. The brittleness index is an arithmetic mean value of an intermediate parameter obtained through Young modulus data and an intermediate parameter obtained through Poisson's ratio data. Wherein the intermediate parameter obtained through the Young modulus data is a normalized value of the Young modulus, and the intermediate parameter obtained through the Poisson's ratio data is a normalized value of the Poisson's ratio. According to the method, multiple linear regression is carried out by using conventional logging data, the shear wave time difference model is constructed to fit the shear wave data, the correlation coefficient between the obtained brittleness index and the rock brittleness index obtained by the array acoustic logging data is high, and the method is suitable for solving the rock brittleness index in the absence of the array acoustic logging data. And calculating the brittleness index of the strong-heterogeneity shale formation aiming at complex mineral components in the paleozoic region.

The invention belongs to the technical field related to structure optimization, and discloses a cross-scale topological optimization method of an auxetic metamaterial with a specified deformation mode, which comprises the following steps: (1) according to a given metamaterial function target, introducing an elastic tensor component constraint condition to establish a negative Poisson's ratio microstructure topological optimization model; (2) gradually changing the volume rate constraint of the initial microstructure to obtain a series of negative Poisson's ratio gradient microstructures with different equivalent densities; (3) constructing a multi-phase material interpolation model based on a Kriging model, constructing an auxetic metamaterial cross-scale topological optimization model with a specified deformation mode, and deducing the sensitivity of a target function to design variables; and (4) calculating and updating the design variable until the output meets the convergence condition, and outputting the auxetic metamaterial with the target deformation mode. According to the method, the limitation that the deformation mode of the traditional auxetic metamaterial cannot be locally regulated and controlled is overcome, and the design efficiency of the cross-scale design problem of the two-dimensional auxetic metamaterial under the complex condition is improved.

The invention relates to the technical field of bearing life calculation, in particular to a transmission bearing installation pre-tightening amount calculation method and system, and the method comprises the steps: S1, building a finite element mesh model of a transmission housing and a shaft through finite element simulation software based on predefined material attributes; the material attributes comprise elastic modulus, Poisson's ratio and thermal expansion coefficient of the transmission shell and the shaft; s2, based on the actual working condition of transmission assembly life simulation analysis, importing the finite element mesh model of the transmission shell and the shaft into a pre-constructed multi-body dynamics simulation model of the transmission shell, and establishing node connection between the finite element mesh model of the transmission shell and the shaft and a transmission part in the multi-body dynamics simulation model; s3, setting a detection object and a design variable, and adopting a preset strategy to obtain a target mapping curve of the detection object and the design variable; compared with the prior art, the optimal relation between the pre-tightening amount and the service life of the bearing can be quickly determined, so that the service life of the bearing is maximized.

The invention discloses a method for measuring fan blade root stress based on a fiber bragg grating sensor. According to the method, 6-10 key measurement points are selected in a blade root area of a fan blade, a pair of FBG sensors is installed at each measurement point, one FBG sensor is used for stress measurement (affected by strain and temperature at the same time), the other FBG sensor is used for temperature compensation, and decoupling of temperature and strain signals is achieved. The system adopts a single-mode optical fiber, a broadband light source (the wave band is 1525-1565 nm, and the power is 10-20 mW) and a high-resolution spectrum analyzer (the resolution is smaller than or equal to 1 pm, and the sampling rate is larger than or equal to 100 Hz or 1 kHz) to collect optical signals reflected by an FBG sensor in real time, measured wavelength shift is converted into accurate strain data through temperature compensation and a strain calculation formula, and the optical signals are transmitted to the FBG sensor. And calculating a stress value by combining the Young modulus and Poisson's ratio of the material. The method has the advantages of being high in precision, high in real-time performance, resistant to electromagnetic interference and suitable for seaborne, high-altitude and other severe environments, and reliable data support can be provided for dynamic stress monitoring, fatigue life prediction and fault early warning of the fan blade.

The present invention discloses an X-shaped negative Poisson's ratio local resonance module and its supporting metamaterial disc structure. The X-shaped negative Poisson's ratio local resonance module includes an X-shaped structural wall, an X-shaped negative Poisson's ratio structural unit and a local oscillator, wherein the local oscillator includes a soft coating layer and a cylindrical core, and the local oscillator is fixed on the X-shaped negative Poisson's ratio structural unit in an embedded form; the supporting metamaterial disc structure is composed of a plurality of X-shaped negative Poisson's ratio local resonance modules. The X-shaped negative Poisson's ratio structural units are circumferentially distributed around the outer wall of the inner circular ring column in the X-shaped structural wall to the inner wall of the outer circular ring column, and the outer wall of the inner circular ring column and the inner wall of the outer circular ring column are connected by the X-shaped structural unit wall. The X-shaped negative Poisson's ratio local resonance module is installed on a beam-type or tube-type base structure through the inner circular ring column. The present invention can achieve multi-scale and multi-level vibration suppression through the X-shaped negative Poisson's ratio local resonance module, improve the stability of the disc-shaped parts, and is easy to install and convenient to process.