1004 results about "Poisson's ratio" patented technology

The invention described herein relates to structured porous materials, where the porous structure provides a tailored Poisson's ratio behavior. In particular, the structures of this invention are tailored to provide a range in Poisson's ratio ranging from a negative Poisson's ratio to a zero Poisson's. Two exemplar structures, each consisting of a pattern of elliptical or elliptical-like voids in an elastomeric sheet, are presented. The Poisson's ratios are imparted to the substrate via the mechanics of the deformation of the voids (stretching, opening, and closing) and the mechanics of the material (rotation, translation, bending, and stretching). The geometry of the voids and the remaining substrate are not limited to those presented in the models and experiments of the exemplars, but can vary over a wide range of sizes and shapes. The invention applies to both two-dimensional structured materials as well as three dimensionally structured materials.

The invention provides a method and a device for synchronous measurements on dynamic and static elastic parameters of rocks by using a rock triaxial anti-compression testing device. The method comprises: sealing a test rock sample in a triaxial autoclave filled with hydraulic oil, applying an oil pressure by an axial pressure control system, applying a confining pressure by a confining pressure control system, and applying a pore pressure by a pore pressure control system; acquiring propagation speeds of longitudinal waves and transverse waves in the test rock sample by a computer acquisition and control system, and calculating the dynamic Young modulus and the dynamic Poisson ratio according to the propagation speeds; and acquiring deformation parameters of the test rock sample during a loading process by the computer acquisition and control system, and calculating the static Young modulus and the static Poisson ratio according to the deformation parameters. The method and the device can ensure validity and accuracy of hydrocarbon reservoir rock mechanical parameter measurements in thousands of meters deep underground and under the conditions of complex confining pressure, high temperature, high pore pressure and polyphase fluid.

Stents of the type used to treat and prevent localized flow constriction in body vessels are based upon negative Poisson's ratio (NPR) structures. An auxetic stent constructed in accordance with this invention comprises a tubular structure having two ends defining a length with a central longitudinal axis and an axial view defining a cross section. The tubular structure is composed of a plurality of unit cells with two different configurations, called V-type and X-type. In V-type auxetic stents, each unit cell comprises a pair of side points A and B defining a width, a first pair of members interconnecting points A and B and intersecting at a point C forming a first V shape, and a second pair of members interconnecting points A and B and intersecting at a point D forming a second V shape. In X-type auxetic stents, each unit cell comprises eight points from A to H defining an outline of the unit cell. Eight straight or curved members interconnecting points A and B, B and C, C and D, C and E, E and F, F and G, G and H, G and A, respectively, forming the X-type unit cell. In both configurations, the unit cells are connected in rows and columns, such that compression of the structure between the two ends thereof causes the cross section of the structure to shrink in size. The auxetic structure configurations invented can also be used, with similar dimensions or significantly different dimensions, for other applications, such as in a nano-structural device, a tubal fastener design, or in an application associated with a large oil pipe or other pipelines.

The invention discloses a method for testing tensile modulus of a brittle material, which is characterized by comprising the following steps of: arranging a test sample on a Brazilian split tester; symmetrically applying line load to the test sample in the radial direction of the test sample; measuring the total displacement of center of the test sample in the diameter direction, wherein the direction of the total displacement is vertical to the load applying direction of the test sample; calculating to obtain the tensile modulus Et of the material according to the following formula, wherein Et is the tensile modulus, sigma t is the Brazilian split tensile strength; Pt is the line load, L is the length of the test sample, D is the diameter of the test sample, Mu is the Poisson's ratio, and Delta ut is the total displacement of the center of the test sample in the diameter direction. The method for testing the tensile modulus of the brittle material can guarantee more accurate test result.

A seating unit includes a generally horizontal seat portion and a generally upright back portion. The back portion includes a flexible membrane or mesh extending in first and second directions. The mesh defines a generally upright user support surface. At least a portion of the mesh comprises an auxetic material having a negative Poisson's ratio whereby stretching of the auxetic portion of the mesh in at least one of the first and second directions causes the mesh to expand in the other of the first and second directions.

The present invention relates to composite polymer material, and is especially stretching material with negative Poisson's ratio and its preparation process and use. The foamed material obtained through secondary foaming process or screw extrusion foaming process has microscopic double fan-shaped composite structure with middle layer of regular honeycomb structure, outer layer of ordered gradually lengthened arrangement and micropores of 80-150 micron size. The foamed material has the mechanical performance of perpendicularly expanding while being stretched and perpendicularly contracting while being extruded. By means of special preparation process, the foamed material may have raised compression resistance, shock absorption, rebound elasticity and other mechanical performance. The unique mechanical performance makes the material possess application in composite board, waste water treatment, deep water job and other fields.

A structured porous metamaterial includes a three-dimensional matrix of at least one repeating base unit. The matrix is formed from an array of at least eight base units, each base unit including a platonic solid including at least one shaped void, wherein each base unit has void geometry tailored to provide a porosity of between 0.3 and 0.97, and to provide the metamaterial with a response that includes a Poisson's ratio of 0 to −0.5 when under tension and compression, or negative linear compression (NLC), negative area compression (NAC), zero linear compression (ZLC), or zero area compression (ZAC) behaviour when under pressure.

The present invention is platform Brazil sample test method of measuring the tensile strength of fragile material. By means of 3D elastic mechanical number analysis, the stress distribution regulation of the fragile material in different height / diameter ratio and different Poisson's ratio conditions may be obtained. Proper fragile material strength theory is selected and the cracking initiating from the end surface center line of the sample is stipulated as the effective damage, so as to obtain tensile strength calculation formulas for the test under different height / diameter ratio and different Poisson's ratio conditions. Based on the tensile strength calculation formulas, the material tensile strength based on the strength theory may be obtained through measuring the sample sizes, Poisson's ratio, damage load and compression strength.

Ultrasonic signals obtained at a range of angles are fit to a material independent model to derive both axial and lateral strain and thus parameters dependent on lateral strain including Poisson's ratio and shear strain.

Bulk solidifying amorphous alloys exhibiting improved processing and mechanical properties and methods of forming these alloys are provided. The bulk solidifying amorphous alloys are composed to have high Poisson's ratio values. Exemplary Pt-based bulk solidifying amorphous alloys having such high Poisson's ratio values are also described. The Pt-based alloys are based on Pt—Ni—Co—Cu—P alloys, and the mechanical properties of one exemplary alloy having a composition of substantially Pt57.5Cu14.7Ni5.3P22.5 are also described.

The invention belongs to a functional polymer foam material, relates to a cell structure, an arrangement mode and mechanical performances of a material, and especially relates to a bionic negative-Poisson's ratio material and a preparation method thereof. The bionic negative-Poisson's ratio material having a special negative Poisson's ratio structure is designed and prepared based on the micro-porous structure of natural foam and a negative Poisson's ratio generation principle in the invention. The bionic negative-Poisson's ratio material is a porous foam structure material prepared by processing a thermoplastic plastic through a screw extruder, pores of the material are elongated honeycomb micro-pores, and the longer axes of the elongated honeycomb micro-pores are dispersedly arranged along a radial direction layer by layer from the central axis to the outside. When the material encounters impact, impact force is rapidly converted to deformation energy because of the bidirectional shrinkage of the negative Poisson's ratio and is absorbed, and simultaneously the density is rapidly increased, so the impact resistance of the material is enhanced.

The invention discloses a geometric measurement method of Poisson's ratio and Young's elastic modulus of a thin film material, the periphery of the thin film material to be detected is clamped for leading the thin film material to form a circular thin film with the radius of a and the clamped periphery, evenly distributed loads q are imposed on the circular thin film, the deflection value w(r) ofany two points on the circular thin film is measured, a calculation expression formula of the Poisson's ratio and the Young's elastic modulus of the thin film is deducted according to the accurate analytical solutions which are given out by Hencky of the circular thin film with the clamped periphery under the action of the evenly distributed loads, and the Poisson's ratio and the Young's elastic modulus of the thin film can be accurately calculated by utilizing the deflection value ratio of any two points on the circular thin film. The geometric measurement method of the Poisson's ratio and the Young's elastic modulus of the thin film has the advantages of simple and feasible operation, few measurement parameters, more accurate solved Poisson's ratio and the Young's elastic modulus and definite mechanical and physical significances.

An open-cell carbon nanotube foam is made of a plurality of separated carbon nanotubes. The foam exhibits a Poisson's ratio substantially equal to zero, a compressibility of at least 85%, a recovery rate of at least 120 mm / min, a compressive strength of at least 12 MPa, a sag factor of at least 4, a fatigue resistance to no more than 15% permanent deformation when subjected to at least 1,000 compressive cycles at a strain of 85%, and / or a resilience of between 25% and 30%. The carbon nanotubes may be multiwalled carbon nanotubes that are aligned parallel to a thickness of a film comprising the foam.

The invention provides a shale gas pool construction and production favorable area comprehensive determining method. The method includes the steps of 1) collecting indicator data required for construction and production favorable area determining in a work area; 2) drawing a hydrocarbon generation favorable area plan of the work area through the combination with three indicators of the total content of organic carbon, the organic matter maturity and the content of shale gas; 3) combining Young's modulus with Poisson's ratio for calculating a fracturing index Fi and screening out a favorable geological development area through the combination with three indicators of the fracturing index, the formation pressure coefficient and the burial depth; 4) defining the product of the total content of organic carbon, the fracturing index, the formation coefficient and the thickness of quality shale as a gas testing indicator, screening out development effects of reservoir in the work area with the gas testing indicator and drawing a gas testing favorable area plan of the work area; 5) finally obtaining a construction and production favorable area plan of the work area. According to the shale gas pool construction and production favorable area comprehensive determining method, the favorable hydrocarbon generation and development area can be finally and comprehensively determined by screening out important indicators required for the selection of a preferred shale gas construction and production core area.

The present invention provides elastic constant and visco elastic constant measurement apparatus etc. for measuring in the ROI in living tissues elastic constants such as shear modulus, Poisson's ratio, Lame constants, etc., visco elastic constants such as visco shear modulus, visco Poisson's ratio, visco Lame constants, etc. and density even if there exist another mechanical sources and uncontrollable mechanical sources in the object. The elastic constant and visco elastic constant measurement apparatus is equipped with means of data storing 2 (storage of deformation data measured in the ROI 7 etc.) and means of calculating elastic and visco elastic constants 1 (calculator of shear modulus etc. at arbitrary point in the ROI from measured strain tensor data etc.), the means of calculating elastic and visco elastic constants numerically determines elastic constants etc. from the first order partial differential equations relating elastic constants etc. and strain tensor etc.

A Distributed Acoustic Sensing (DAS) fiber optical assembly comprises adjacent lengths of optical fiber A, B with different directional acoustic sensitivities, for example by providing the first length of optical fiber A with a first coating 35, such as acrylate, and the second length of optical fiber B with a second coating 36, such as copper, wherein the first and second coatings 35 and 36 may be selected such that the Poisson's ratio of the first length of coated fiber A is different from the Poisson's ratio of the second length of coated fiber B. The different Poisson's ratios and / or other properties of the adjacent lengths of optical fiber A and B improve their directional acoustic sensitivity and their ability to detect broadside (radial) acoustic waves.

The invention relates to a structured porous metamaterial. The structured porous metamaterial comprises a three-dimensional matrix of at least one repeating base unit, wherein the matrix is formed from an array of at least eight base units, each base unit comprises a platonic solid including at least one shaped void, each base unit has void geometry tailored to provide a porosity of between 0.3 and 0.97; or provide the metamaterial with a response comprising at least one of a Poisson's ratio of 0 to -0.5 when under tension and compression; or negative linear compression (NLC), negative area compression (NAC), zero linear compression (ZLC), or zero area compression (ZAC) behaviour when under pressure.

Systems and methods which determine geologic properties using acoustic analysis are shown. Acoustic signals are collected during processing (e.g., crushing, shearing, striking, compressing, etc.) of geologic media, such as rock samples, for determining geologic properties according to embodiments. The acoustic signals collected may include frequency information, amplitude information, time information, etc. which may be utilized in determining geologic properties, such as geologic media properties (e.g., mineralogy, porosity, permeability, sealing capacity, fracability, compressive strength, compressibility, Poisson's Ratio, Youngs Modulus, Bulk Modulus, Shear Modulus), geologic structure properties (e.g., lithology, seal quality, reservoir quality), geologic acoustic properties (e.g., acoustic logging effectiveness, acoustic response, natural or harmonic frequencies, etc.). Embodiments may be used to provide determination of geologic properties from a variety of geologic media samples, such as cuttings, core samples, etc.

The invention relates to a preparation method of metal powder, in particular to a preparation method for a sintered copper powder material of a heat pipe. The method comprises the following steps in sequence: smelting, water atomization, dehydrating, drying, reducing, smashing and antioxidant treatment, wherein water jet torrent set in the water atomization process comprises a tapered water curtain formed by the water jet torrent and two V-shaped water curtains formed by intersection of two pairs of planar water jet torrent; the tip of the tapered water curtain faces downwards, and the axial lead of the tapered water curtain is vertical; straight lines formed by the crossing angles of the two V-shaped water curtains are vertical to each other, and the crossing angles of the two V-shaped water curtains are positioned below the tip of the tapered water curtain; and in the water atomization process, copper liquid flow falls along the axial lead of the tapered water curtain and is sequentially contacted with the tapered water curtain and the V-shaped water curtains. The invention has the advantages that the energy consumption and the production cost are lowered, the product quality is obviously improved, and the problem of producing copper powder with a low Poisson's ratio by the water atomization method is solved.

The invention discloses a negative-Poisson-ratio structure type energy absorption box and a multi-objective optimization method therefor. The negative-Poisson-ratio structure type energy absorption box consists of an energy absorption box body (1), a front mounting plate (2), a back mounting plate (5) and a three-dimensional negative-Poisson-ratio structure type inner core (3). The three-dimensional negative-Poisson-ratio structure type inner core consists of a large amount of negative-Poisson-ratio unit cell structures, so that parameters of the negative-Poisson-ratio unit cell structures have a great influence on energy absorption performance of the energy absorption box. The invention provides the multi-objective optimization method based on the negative-Poisson-ratio structure type energy absorption box. The method comprises the steps of establishing an objective function by taking the parameters of part of the negative-Poisson-ratio unit cell structures as optimization variables; setting constraint conditions; building a negative-Poisson-ratio structure type energy absorption box optimization model; and performing multi-objective optimization on the negative-Poisson-ratio structure type energy absorption box by adopting a multi-objective particle swarm optimization algorithm.

The invention discloses a negative poisson ratio structural component based on an inner sunken hexagonal multi-cell unit. The negative poisson ratio structural component comprises a plurality of unitcell structures, each of the unit cell structures consists of two inner sunken hexagons, the inner sunken hexagons are in a left-right symmetric dovetail shape, and every two inner sunken hexagons arearranged in an orthogonal mode and intersect at two concave angle apexes to form a complete unit cell structure; the multiple unit cell structures are connected with each other horizontally in both directions by sharing one support cell arm, and are extended in the horizontal direction to form a continuous unit layer; and a plurality of unit layers are connected with each other in the vertical direction by sharing curved ribs to form a multi-layered cross-aligned inner sunken honeycomb-shaped three-dimensional negative poisson ratio structure. According to the negative poisson ratio structural component based on the inner sunken hexagonal multi-cell unit, a significant negative poisson ratio effect is achieved, higher elastic modulus, shear modulus and storage modulus can be generated when loaded, better rebound toughness and fracture resistance are achieved and improved with the enhancement of the negative poisson ratio effect.

The invention provides a sound absorbing structure and a vehicle part with the same. The sound absorbing structure is constituted of a housing having a hollow portion and an opening and a vibration member composed of a board or diaphragm. The vibration member is a square-shaped material having elasticity composed of a synthetic resin and is bonded to the opening of the housing, thus forming an air layer closed inside the sound absorbing structure by the housing and the vibration member. In the sound absorbing structure, when the lateral / longitudinal dimensions of the air layer and characteristics of the vibration member (e.g. a Young's modulus, thickness, and Poisson's ratio) are set such that the fundamental frequency of a vibration occurring in a bending system falls within 5% and 65% of the resonance frequency of a spring-mass system, a vibration mode having a large amplitude occurs in a frequency band lower than the resonance frequency of the spring-mass system, this improving the sound absorption coefficient.

A golf club head with at least one cavity including a fill material comprising a polymer and a plurality of microscopic glass bubbles, and methods of manufacturing such golf club heads, are disclosed herein. In particular, the golf club head is an iron having a striking face, a rear portion, and an internal cavity disposed behind the striking face, which is at least partially filled with the fill material. The plurality of microscopic glass bubbles constitutes at 5-70% of the volume of the fill material, and more preferably approximately 20-30% of the volume of the fill material. The polymer material preferably is a polyurethane having a Poisson's ratio of 0.40-0.50. In some embodiments, the fill material takes the form a medallion affixed to a rear surface of the striking face, while in others, the fill material is injected into the internal cavity.

The invention discloses a method for determining a maximum deflection value of a pre-stressed circular thin film under a uniformly distributed load. The method comprises the following steps: fixedly clamping the circular thin film with radius a, thickness h, elastic Young's modulus E, Poisson's ratio V and prestress sigma0 on circumference of the circular thin film, and applying a uniformly distributed load value q in the transverse direction, and therefore, through static equilibrium analysis on the basis of axisymmetrical deformation of the circular thin film, the maximum deflection value wm of the thin film is accurately determined through the measured value q of the load.

NPR (negative Poisson's ratio) components for vehicle and other applications generally assume a tubular structure defining an axis, a length and a cross section. The structure is composed of a plurality of nested, double-V unit cells, each unit cell comprising a pair of side points A and B defining a width, a first pair of tensile members interconnecting points A and B and intersecting at a point C forming a first V shape, a second pair of stuffer members interconnecting points A and B and intersecting at a point D forming a second V shape. The unit cells are connected in a first direction with the point B of one cell being connected to point A of an adjoining cell, and so on, until completing a continuous band. The unit cells are further connected in a second direction with the point D of one cell being connected to point C of an adjoining cell. In one embodiment, the bands are stacked radially outwardly from the axis to form a bushing. In accordance with a second embodiment, the bands are stacked lengthwise along the structure to form a joust bumper.

A method is provided for determining Young's modulus and, if desired, Poisson's ratio of a coating on a substrate wherein load-displacement indentation data in the elastic region (either elastic loading or unloading) generated using an indenter is analyzed to interpret the elastic repsonse of a coated material. The data analysis pursuant to the invention is based on an extended Hertzian analysis developed for thin-film coatings.

The present invention provides elastic constant and visco elastic constant measurement apparatus etc. for measuring in the ROI in living tissues elastic constants such as shear modulus, Poisson's ratio, Lame constants, etc., visco elastic constants such as visco shear modulus, visco Poisson's ratio, visco Lame constants, etc. and density even if there exist another mechanical sources and uncontrollable mechanical sources in the object. The elastic constant and visco elastic constant measurement apparatus is equipped with means of data storing 2 (storage of deformation data measured in the ROI 7 etc.) and means of calculating elastic and visco elastic constants 1 (calculator of shear modulus etc. at arbitrary point in the ROI from measured strain tensor data etc.), the means of calculating elastic and visco elastic constants numerically determines elastic constants etc. from the first order partial differential equations relating elastic constants etc. and strain tensor etc.