432 results about "Poisson's ratio" patented technology

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 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 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 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 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 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 rock unconventional reservoir carbon dioxide fracturing temperature field simulation method and system, and belongs to the technical field of oil and gas exploitation. Rock unconventional reservoir parameters and wellbore parameters are obtained, fluid physical property parameters of carbon dioxide fracturing fluid flowing in a wellbore are determined, and a multi-dimensional physical partition model is constructed; the unconventional reservoir is divided into a plurality of physical areas including a fluid flowing area, a static fluid area, a solid area and a porous medium area; thermal boundary conditions of all physical areas are coupled through an energy conservation equation, stratum elasticity modulus and Poisson's ratio are added to the thermal boundary conditions, a thermal-force coupling equation is constructed, carbon dioxide fracturing construction parameters obtained in real time are estimated, temperature field distribution nephograms of carbon dioxide fracturing fluid at different moments in the shaft flowing process are obtained, and the temperature field distribution nephograms of the carbon dioxide fracturing fluid at different moments are calculated. According to the method, the temperature distribution rule of different fracturing stages in the shaft-crack direction can be truly reflected.

The invention relates to the technical field of machining simulation, in particular to a composite material ring piece low-stress machining method based on finite element analysis. The method comprises the following steps: constructing a two-dimensional finite element model of the composite material ring piece; grid division is carried out on the geometric model, and the structure is decomposed into units; setting boundary conditions and loads of the simulation model; defining material attributes including density, thermal conductivity, specific hot melting, elastic modulus, Poisson's ratio, plasticity and creep; setting processing and heat treatment parameters, including processing procedures, processing amount, heat treatment temperature and time; the simulation model is operated, and the response of the geometric model under the given boundary and loading condition is obtained; and analyzing an operation result, summarizing an influence rule of machining parameters and heat treatment setting on machining stress, and optimizing a machining scheme. According to the method, a stable component low-stress machining scheme can be rapidly obtained through an analogue simulation technology for the machining process of the composite material ring piece, and high-precision machining of the large-size fiber reinforced composite material ring piece is achieved.

The invention discloses a tunnel rock mass water burst and mud burst prediction method and system based on an XGBoost-RF fusion algorithm, and belongs to the technical field of geological disaster prediction. The method comprises the following steps: firstly, preprocessing seismic wave data, and extracting various geological response characteristics including longitudinal wave velocity, wave velocity variation coefficient, Poisson's ratio and the like; then respectively training an XGBoost model and a random forest model, and carrying out probability fusion through a soft voting strategy; and finally, outputting a risk level classification result based on the weighted probability. The core innovation of the invention lies in that the feature fine recognition capability of the XGBoost model and the anti-noise characteristic of the random forest model are effectively combined through algorithm fusion, and the probability calibration and weight optimization mechanism is adopted, so that the recognition precision of middle and high risk categories is remarkably improved. Experiments show that according to the method, the average recall rate of key categories on a test set reaches 0.9925, the overall accuracy rate is 0.990, and the problems that a traditional method is high in high-risk geologic body missed judgment rate and insufficient in generalization ability are effectively solved.

The invention discloses a mechanical metamaterial cell element with a zero Poisson's ratio property, and belongs to the technical field of mechanical metamaterials. The upper top plate and the lower bottom plate are symmetrically arranged, the upper cleat nail set and the lower cleat nail set are arranged at the four corners of the inner side faces of the upper top plate and the lower bottom plate, the elastic body set is connected through the upper cleat nail set and the lower cleat nail set, and the flexible hinge component set is arranged at the midpoint position of four side lines of the upper top plate and the lower bottom plate. The flexible hinge component set keeps inward pre-bending through the pre-tension of the elastomer set, and when the cell element bears an axial load, the flexible hinge component set generates coordinated inward bending deformation, so that the cell element shrinks in the axial direction, the transverse size is kept stable, the axial zero Poisson's ratio characteristic is achieved, and meanwhile the energy absorption capacity is achieved. The cell element is based on elastic deformation, has self-recovery capability and long cycle life, adopts modular design, is convenient to assemble, disassemble and maintain, and is suitable for application scenes of aerospace buffer devices, biomedical implants, precise instrument supporting structures and the like.

The invention relates to the technical field of coal mining and rock mechanics numerical simulation, and discloses a stress field reconstruction method of a plane strain numerical simulation model for coal mining, and the method comprises the following steps: firstly, obtaining an actually measured vertical stress increment and an actually measured bearing pressure peak value position of a stope face; then, an initial plane strain numerical simulation model is constructed, the space error between the peak position of the simulated bearing pressure and the actual measurement position meets a preset threshold value by adjusting the excavation step pitch, and therefore the numerical simulation calculation state is locked to eliminate space-time dislocation; a simulation strain increment is extracted in a locked state, a theoretical vertical stress difference equation is constructed based on an elastic mechanics plane strain constitutive relation, and a parameter inversion equation set is established in combination with multi-measurement-point data; and solving the corrected elastic modulus and Poisson's ratio by using a least square optimization algorithm. According to the method, through physical state locking and incremental theory inversion, system errors are effectively eliminated, and the reconstruction precision and mechanical preciseness of the mining-induced stress field are improved.

The application belongs to the technical field of aerospace, weapon equipment buffering and energy absorption protection, and particularly relates to a spring-like superstructure capable of repeated and efficient buffering and energy absorption, which is formed by spirally winding hollow tubes or filling tubes with circular, square, hexagonal, concave negative Poisson's ratio, self-locking or other special cross-sectional shapes; by adjusting the distribution forms of geometric parameters such as the spiral angle, polar angle, number of turns, pitch, winding diameter, tube diameter and wall thickness of the structure, the mechanical properties of the structure can be regulated and controlled. Compared with conventional foam, honeycomb and other traditional energy absorption materials, the application can achieve the purpose of efficient buffering and energy absorption, and can achieve the effect of being reusable.

The invention discloses a fuzzy neural network-based intelligent tension control method and system for a plateau tunnel pre-stressed anchor rod, and the system is characterized in that a free section of the anchor rod is sleeved with a negative Poisson ratio outer sleeve, a magneto-rheological regulation and control cavity is formed in the anchor rod, magneto-rheological fluid is injected into the magneto-rheological regulation and control cavity, and a friction power generation-sensing assembly is mounted at the tail end of the anchor rod; therefore, the anchor rod unit integrating friction increase along with the load, adjustable damping and self-energized sensing is formed. In the tensioning process, the friction power generation-sensing assembly is used for measuring the elongation of the anchor rod and providing self-powered energy, the pressure of a magneto-rheological regulation and control cavity and the displacement of a piston are collected, a state vector containing design prestress, the elongation, equivalent damping force and environment vibration indexes is constructed and input into a fuzzy neural network controller, and the state vector is calculated. The expansion amount of the hydraulic jack and the current of the electromagnetic coil are output, and intelligent application, dynamic compensation and long-term monitoring of prestress of the anchor rod group are achieved. Self-sensing, self-adaptive adjustment and active friction increasing of the pre-stressed anchor rod group can be achieved without an external power source.

The invention discloses a landslide buffering and energy absorbing device based on a positive and negative Poisson's ratio alternating material, which comprises a protection plate I and a protection plate II which are oppositely arranged, and a positive and negative Poisson's ratio alternating layer is clamped between the protection plate I and the protection plate II; the positive and negative Poisson's ratio alternating layers comprise positive Poisson's ratio honeycomb layers and negative Poisson's ratio honeycomb layers which are alternately arranged in the transverse direction; the elastic modulus of the negative Poisson's ratio honeycomb layer material is not less than that of the positive Poisson's ratio honeycomb layer material; the positive Poisson's ratio honeycomb layer and the negative Poisson's ratio honeycomb layer are connected through a connecting rod layer, and the connecting rod layer is connected with the positive Poisson's ratio honeycomb layer and the negative Poisson's ratio honeycomb layer on the two sides in an attached mode. By reasonably arranging the positive and negative Poisson's ratio alternating layers, the problems of energy absorption and protection of the landslide blocking structure and insufficient rigidity of a single negative Poisson's ratio material are solved, and the blocking structure can be effectively reinforced by applying the positive and negative Poisson's ratio alternating layers to the head-on collision side of the landslide blocking structure.

The invention discloses an energy absorption enhancement type lattice structure with the Poisson's ratio adjustable in all directions and a design method, and relates to the field of honeycomb structures. The method comprises the steps that S1, two-dimensional honeycomb structure cell elements with the Poisson's ratio capable of being adjusted according to the thicknesses of inner and outer ribs are constructed; s2, overlapping the two two-dimensional honeycomb structure cell elements in the in-plane direction at 90 degrees, and performing Boolean union intersection operation to obtain four three-dimensional honeycomb units; s3, sequentially connecting the four middle vertexes of each three-dimensional honeycomb unit to form a quadrilateral rib, sequentially connecting the upper vertexes of the four three-dimensional honeycomb units to form a quadrilateral rib, and sequentially connecting the lower vertexes of the four three-dimensional honeycomb units to form a quadrilateral rib to obtain a three-dimensional honeycomb structure cell element; s4, performing array to obtain a three-dimensional lattice structure; when being pressed in the in-plane direction, the two-dimensional honeycomb structure cell element shows the same Poisson's ratio polarity as the corresponding two-dimensional honeycomb structure cell element in the in-plane direction. According to the constructed two-dimensional honeycomb structure cell elements, the overall rigidity of the structure is improved, and a novel three-dimensional lattice structure with Poisson's ratio symbol anisotropy is generated through Boolean operation.

The negative poisson ratio energy absorption device comprises a honeycomb structure formed by a plurality of unit cell structure arrays, and each unit cell structure is formed by combining a plurality of plane energy absorption units around the same central axis in a radial shape in a crossed mode. Each plane energy absorption unit comprises an inwards-concave negative Poisson's ratio structure, two bionic treetop structures symmetrically arranged on the upper side and the lower side of the inwards-concave negative Poisson's ratio structure in the axial direction, and two connecting rods horizontally extending from the left side and the right side of the inwards-concave negative Poisson's ratio structure to the outer side. The bionic treetop structure comprises an arc-shaped top and a plurality of supporting rods distributed in a fan shape, one end of each supporting rod is connected to the arc-shaped top, and the other end of each supporting rod is connected to the concave negative Poisson's ratio structure; the device has the advantages that the device can adapt to multi-angle impact, and efficient and uniform energy absorption and light-weight protection are achieved through the negative Poisson's ratio effect.

The invention discloses a buffering and damping structure device of a bionic echinopsis tubiflora arris bone, which comprises an upper panel, a lower panel and a buffering piece, and is structurally provided with a double compression-torsion system and a double vibration system, so that the buffering and damping structure device can ensure sufficient bearing capacity and has better damping capacity at the same time. The bionic ball cactus rib is spherical, and a single rib is composed of an upper section, a middle section and a lower section. Wherein the upper end and the bottom end have the same radius with the vertical line of the center point of the ball, form a certain angle and have a twisting effect. The radius of the middle portion is larger than the radiuses of the upper portion and the bottom portion, rotation and Poisson's ratio effects can be generated when loads are borne, the transverse inertia effect is achieved, and efficient buffering and vibration reduction can be achieved. And the edge bone presents a crease with a certain angle. And after being subjected to a vibration load, the middle part of the crease can be bent and spread, vibration energy is consumed, and the equipment is further protected. And a compression-torsion structure can greatly reduce the weight of the structure, and the mass and the transportation cost in the transportation process are reduced.

The invention provides a block model construction method for underground cavern group surrounding rock stability analysis, which comprises the following steps: generating an initial block according to a topological relation between a fault and a joint in a three-dimensional geologic model, and carrying out geometric reconstruction on a block interface through Boolean operation to eliminate overlapping; automatically matching lithology types of the divided blocks with an engineering attribute database, dynamically distributing elastic modulus, Poisson's ratio and tensile strength, establishing rock attribute mapping, synchronously iteratively solving interaction equations of a mechanical deformation field, a seepage pressure field and a temperature stress field in a unified solver, and performing multi-physics field coupling; a potential sliding surface is automatically identified according to a multi-physics field coupling result, a sliding surface friction coefficient and shear strength are fused to calculate a safety coefficient, non-overlapping block division is carried out by adopting a topological relation of faults and joints, an interaction equation of a mechanical deformation field, a seepage pressure field and a temperature stress field is synchronously iterated through a unified solver, and a non-overlapping block is obtained. And accurate quantitative analysis of surrounding rock stability is realized.

The invention discloses a self-adaptive multi-stage negative Poisson's ratio energy absorption device and a manufacturing method.The self-adaptive multi-stage negative Poisson's ratio energy absorption device comprises a shell and a negative Poisson's ratio honeycomb structure arranged in the shell, and the negative Poisson's ratio honeycomb structure is formed by a plurality of self-adaptive negative Poisson's ratio unit cell arrays; each self-adaptive negative Poisson's ratio unit cell comprises a negative Poisson's ratio framework, an upper supporting structure and a lower supporting structure, the upper supporting structure and the lower supporting structure are connected to the interior of the negative Poisson's ratio framework, a horizontal supporting platform is arranged in the middle of the negative Poisson's ratio framework, and a preset gap allowing the negative Poisson's ratio framework to shrink and deform is formed in the middle of the horizontal supporting platform of the negative Poisson's ratio framework; the upper supporting structure extends downwards from the joint with the negative Poisson's ratio framework and is provided with an upper supporting platform, and the lower supporting structure extends upwards from the joint with the negative Poisson's ratio framework and is provided with a lower supporting platform; the self-adaptive graded protection device has the advantages that elastic buffering reusability of low-speed collision and multi-stage efficient energy absorption of high-speed collision can be both considered, and self-adaptive graded protection is achieved.

The application discloses a kind of poisson ratio each direction controllable energy-absorbing enhanced lattice structure and design method, it is related to honeycomb structure field, method includes: S1, constructs the poisson ratio of two-dimensional honeycomb structure cell that can be adjusted according to inner and outer rib thickness;S2, the in-plane direction of two two-dimensional honeycomb structure cell is mutually coincident and placed 90 degrees, carries out Boolean intersection operation, obtains four three-dimensional honeycomb units;S3, the four intermediate vertices of each three-dimensional honeycomb unit are sequentially connected into quadrilateral rib, the upper vertex of four three-dimensional honeycomb units is sequentially connected into quadrilateral rib, and its lower vertex is sequentially connected into quadrilateral rib, to obtain three-dimensional honeycomb structure cell;S4, array obtains three-dimensional lattice structure;When being compressed in in-plane direction, show the same poisson ratio polarity as the in-plane direction corresponding two-dimensional honeycomb structure cell.The two-dimensional honeycomb structure cell constructed by the application improves the overall stiffness of structure, and generates new three-dimensional lattice structure with poisson ratio sign anisotropy by Boolean operation.

This invention relates to hot-stamped components and a method for manufacturing the same. The hot-stamped component comprises a steel plate and an Al-Si based coating layer formed on at least one surface of the steel plate. Residual stress exists in the steel plate of the hot-stamped component, and the peak position of the diffraction lines is changed by altering the incident angle φ while irradiating the steel plate with X-rays. The slope M is obtained by linear regression using the least squares method, and the slope M is multiplied by the residual stress value calculated from the stress constant K obtained from the Young's modulus and Poisson's ratio of the steel plate according to Equation 1, which is between 5 MPa and 70 MPa. [Equation 1] K = -E / 2(1+v)*cotθ*π / 180, where E is the Young's modulus in MPa, v is the Poisson's ratio, and M is the slope of the regression line 2θ-sinθ. 2 θ and 2θ are the diffraction angles in ° without strain, and K is the stress constant in MPa.

The invention discloses a negative Poisson's ratio stent structure for heart and cerebral vessels and an optimization method of the negative Poisson's ratio stent structure, belongs to the technical field of medical instruments, and solves the problems of axial shortening, contradiction between radial supporting force and flexibility and low calculation efficiency in an optimization process of a traditional vascular stent due to a positive Poisson's ratio effect. Wherein a bracket structure of a curved-edge concave hexagonal geometric unit is adopted, and the bracket synchronously extends in the axial direction to present a negative Poisson's ratio effect when being subjected to an expansion load in the radial direction; degradable macromolecules or degradable metals are selected as the material of the stent; according to the optimization method, candidate design is generated through parametric modeling, performance indexes are obtained through finite element simulation, a neural network agent model is trained to predict multi-target performance, a Pareto optimal solution set is obtained through optimization by adopting a multi-target optimization algorithm, and manufacturing parameters are determined through finite element review. According to the invention, the implantation precision and the positioning accuracy of the stent are improved, the mechanical property and the biocompatibility are optimized, and the design efficiency is improved.

This invention relates to the field of novel materials, specifically a novel metamaterial exhibiting both multi-stable state and negative Poisson's ratio properties. It comprises a concave hexagonal frame, two arc-shaped beams positioned on the upper and lower sides of the frame's inner cavity, and a vertical rod. The two arc-shaped beams are fixedly connected to the upper and lower ends of the vertical rod via their respective central portions. When the structure is subjected to a vertical compressive load, the frame's diagonal bracing rotates inward, contracting and compressing the ends of the arc-shaped beams, generating a significant negative Poisson's ratio effect. This process forces the arc-shaped beams to bend and deform towards the center, accompanied by energy dissipation. When the displacement reaches a critical threshold, the arc-shaped beams buckle and overturn, switching to a steady state. This invention, through specific geometric configurations and differentiated material layouts, achieves morphological self-repair after impact and reuse under low-intensity conditions. This metamaterial can be arranged as a two-dimensional periodic array as a unit cell.

The application relates to the technical field of honeycomb sandwich structures, in particular to a double-material curved-edge inner-concave negative Poisson's ratio sandwich plate design method considering material gradient and structure gradient design simultaneously. The method comprises an upper end plate, a core layer and a lower end plate, the core layer is arranged between the upper end plate and the lower end plate and is fixedly connected with the upper end plate and the lower end plate; the core layer is a double-material curved-edge negative Poisson's ratio gradient honeycomb layer structure, and the core layer is obtained by stretching the rear of a double-material inner-concave curved-edge negative Poisson's ratio cell transversely. The internal structure of the plate layer is restructured, so that the problem that lightweight safety cannot be considered simultaneously in the automobile design and production process is solved.

The invention discloses a simulation method, device and equipment for a composite material automobile ceiling, and the method comprises the steps: firstly obtaining material samples of different layers, such as a PU foam layer, a non-woven fabric and glass fiber composite material layer, a sponge layer and a fabric layer, on a target automobile ceiling; acquiring at least one material parameter of elastic modulus, Poisson's ratio and stress-strain curve of the material samples at different temperatures and different strain rates; and then an integral sample piece of the target vehicle ceiling is obtained, material testing and simulation benchmarking are carried out on the integral sample piece to verify whether the obtained material parameters are accurate or not, and if yes, simulation modeling is carried out on the target vehicle ceiling by using the material parameters to obtain a simulation modeling result. Therefore, simulation modeling can be carried out on the target vehicle ceiling by layering the composite material, the influence of various materials with different physical attributes on the mechanical property of the ceiling is fully considered, and the simulation modeling precision and the modeling effect are effectively improved.

A testing method for Young's modulus and Poisson's ratio based on a square plate is provided, which including: obtaining a height, a length, a density, and a quality information of the square plate specimen; measuring the first-order torsional frequencie and the second-order torsional frequencie of the square plate specimen; calculating Poisson's ratio based on the height, the length, the first-order torsional frequency, and the second-order torsional frequency of the square plate specimen; calculating the Young's modulus of the square plate specimen based on the Poisson's ratio and the density. The method establishes a continuous function relationship between the parameter set of the test specimen and the torsional frequency using homotopy method, which can be used to calculate Poisson's ratio. When the material density and Poisson's ratio are known, the Young's modulus can be calculated in conjunction with ANSYS software. The method has advantages in both testing efficiency and accuracy.

The invention relates to the technical field of damping structures, and discloses a shape memory polymer filled multistable negative Poisson's ratio structure damper which comprises a plurality of multistable structure shells which are of a bilateral symmetry structure and made of negative Poisson's ratio materials, cavities are defined in the multistable structure shells, and the multistable structure shells are arranged in an array mode; the shape memory polymer is arranged in the cavity, and the shape memory polymer is made of a shape memory negative Poisson's ratio polymer. The cavity is formed in the multi-stable-state structure shell, the cavity is filled with the shape memory polymer made of the shape memory negative Poisson's ratio polymer, the overall strength and rigidity of the structure can be improved while the negative Poisson's ratio characteristic is kept, and therefore the application range of the negative Poisson's ratio material in the vibration reduction field is expanded. The addition of the shape memory polymer is beneficial to improving the deformation capacity of the whole structure during bearing, and meanwhile, the structure can be recovered to the initial shape after being unloaded based on the recovery capacity of the shape memory polymer.

This invention relates to the fields of microelectromechanical systems (MEMS) and new energy technologies, and discloses a piezoelectric energy harvester based on a nonlinear gradient negative Poisson's ratio structure. Its elastic matrix has a fixed end and a free end, with a negative Poisson's ratio structural segment on it. The piezoelectric transducer element is bonded to the surface of the negative Poisson's ratio structural segment via an epoxy resin adhesive layer. The core innovation lies in the nonlinear monotonically decreasing thickness of the elastic matrix from the fixed end to the free end along its length. This change profile is defined by a specific cubic polynomial function, which can accurately approximate the theoretical model of an isostress beam, making the stress distribution on the matrix surface tend to be uniform during vibration. Simultaneously, the lateral expansion characteristics of the negative Poisson's ratio structural segment and the longitudinal stress enhancement effect of the nonlinear thickness synergistically amplify the charge output of the piezoelectric element. This invention significantly improves the utilization efficiency of piezoelectric materials and the power density of the energy harvester, and has the advantages of compact structure, high energy conversion efficiency, and mass production via 3D printing.

The application discloses a negative Poisson's ratio bidirectional energy dissipation cross type energy dissipation component, which is characterized by comprising a frame (5) and a connecting piece (6), the frame (5) is a rectangular frame, the connecting piece (6) is arranged at the center position of the frame (5), and a core unit (2) is movably connected between the connecting piece (6) and four corners of the frame (5), respectively. Negative Poisson's ratio holes are arranged in the middle part of the core unit (2) in a circulating manner, and the negative Poisson's ratio holes are at least two columns of positive-negative orthogonal semi-recessed hexagonal holes. Under the action of an earthquake, the whole frame will move laterally, the lateral displacement of the frame is transmitted to four supports arranged along two diagonal lines through axial force, then two supports on one diagonal line will be subjected to axial tension, two supports on the other diagonal line will be subjected to axial pressure, and the energy dissipation section of the core member in the support is provided with the recessed hexagonal negative Poisson's ratio holes arranged in a circulating manner, so that the energy dissipation section will be deformed.

The present application belongs to the technical field of structure monitoring based on optical fiber sensing technology, and particularly relates to a strain compensation correction method for optical fiber sensors based on a numerical model. Based on a finite element analysis model for strain transmission of a concrete-optical fiber sensor structure, a theoretical strain transmission rate of a theoretical model of the concrete-optical fiber is determined. The elastic modulus and Poisson's ratio of different materials of a packaging layer of the optical fiber sensor are determined through a material tensile test, a global finite element model of the concrete-optical fiber sensor is established, and the theoretical strain transmission rate of the concrete-optical fiber sensor is calculated. Through a strain monitoring test of the concrete optical fiber sensor, the ratio of the strain monitored by the optical fiber in the concrete to the strain monitored by a strain gauge on the surface of the concrete is determined, the test monitoring value of the strain transmission rate of the concrete-optical fiber sensor is obtained, the error of the theoretical model is corrected through the test value, and the error correction coefficient is determined. The present application is suitable for high-precision compensation correction of strain monitoring data of optical fiber sensors affected by multiple layers of media.