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57 results about "Experimental mechanics" patented technology

Test device and test method for measuring residual stress of bent pipe

The invention relates to a test device and test method for measuring residual stress of a bent pipe and belongs to the technical field of experimental mechanics and residual stress measurement. In the method provided by the invention, the digital speckle correlation technique is combined with the drilling technique, and the method comprises the following steps: using a CCD (charge coupled device) camera to take photos of the bent pipe before and after the bent pipe is drilled; utilizing the digital speckle technique to measure the stretched displacement of two ends of the front and back drilled round holes; and measuring the residual stress of the bent test piece with a confirmed principal stress direction, so as to acquire the residual stress. The digital speckle correlation technique used in the method refers to non-contact measurement. Compared with the traditional electrical testing method, the method has the advantage that the complex process of sticking a foil gauge each time is omitted, thereby being more convenient and simpler. For the measurement of the residual stress of the bent pipe, a column correcting process is added in the method provided by the invention as compared with the traditional method, thus the acquired result is more accurate.
Owner:TSINGHUA UNIV

Method for inversion calibration of microscopic constitutive parameters of metal material on the basis of nanoindentation and finite element simulation

ActiveCN108645704AAchieving precise quantitative descriptionAvoid the problem of too large set of non-inferior solutionsMaterial strength using tensile/compressive forcesMetallic materialsDisplacement control
The invention discloses a method for inversion calibration of microscopic constitutive parameters of a metal material on the basis of nanoindentation and finite element simulation. The method comprises the following steps: S1, carrying out a nanoindentation test on the surface of the metal material through displacement control so as to obtain an experimental indentation response; S2, establishinga nanoindentation and finiteelement model under an ABAQUS or standard module, and carrying out finiteelement simulation to the process of the nanoindentation test on the metal material mentioned in the step S1 so as to obtain a simulated indentation response; and S3, constructing a multi-objective optimization platform, setting optimization objectives and constraint conditions, acquiring a non-inferior optimal solution set Pareto Front through a multi-objective optimization method based on FMOGA-II algorithm, and determining a unique optimal solution. The method provided by the invention has low cost, is rapid and accurate to calculate, is simple and practicable, is extensively applicable to inversion calibration of microscopic constitutive parameters of multi-metal materials, and has highpractical value in computational mechanics, experimental mechanics and engineering practical application.
Owner:SHANGHAI JIAO TONG UNIV

Flexure testing method and flexure testing device for quantitatively characterizing interface binding property of thin-film material

The invention relates to a flexure testing method and a flexure testing device for quantitatively characterizing the interface binding property of thin-film material and belongs to the technical field of property characterization of experimental mechanics and material mechanics. The method is characterized in that uniaxial compression is performed to a sample in the axial direction through a universal material testing machine, and the stress strain values of the sample are recorded; meanwhile, the cross section of the sample is observed synchronously in real time through a CCD camera during the loading process, and stripping characteristics such as critical stress, deflexion and crack length can be recorded in real time during the flexure process; and a relation between the coating and plating-substrate stress strain history and the stripping characteristics is established to characterizing the interface binding property of the coating and plating-substrate. According to the device, the CCD camera, a monitor, an image processing card, a computer, a data processing card, a load sensor and the universal material testing machine are connected in sequence. The invention has the advantages of simple principle, simplicity in sample preparation, clear model, easiness in operation, and the like.
Owner:XIANGTAN UNIV

Preparation and clamping testing device of variable-thickness hydrogel tensile sample with preset clamping rings

The invention discloses a preparation and clamping testing device of a variable-thickness hydrogel tensile sample with preset clamping rings, and belongs to the technical fields of functional polymermaterials and experimental mechanics. The sample is molded through mold casting, wherein a mold is rectangular, the inner cavity is in the shape of a dumbbell and is divided into a clamping section, atransition section and a scale distance section in the length direction, each part meets certain dimension requirements, the three sections are symmetrically distributed by taking the scale distancesection as a center, and the cross section of each section is rectangular; the clamping section and the scale distance section are connected by adopting arc-shaped transition, and are used for avoiding stress concentration. The clamping rings in a pair are prepared, and are placed at the corresponding positions of the clamping sections in advance. Blended hydrogel is poured into a mold cavity, thevariable-thickness hydrogel tensile sample with the clamping rings is obtained after solidification and demolding, and a clamp prepared by a testing machine is used for clamping, so that the operation of a tensile test is carried out. The hydrogel can be effectively prevented from sliding or breaking in the clamping part, and simultaneously, strain measurement is further convenient to perform byadopting an optical stress measurement technology, so that the testing result is more accurate.
Owner:DALIAN UNIV OF TECH

Optical measuring method and apparatus for deformation and strain of high speed rotating structural member

ActiveCN105333832ARealize variable frequency driveQuality improvementUsing optical meansSurface patternLow speed
The invention belongs to the field of rotating machinery experimental mechanics, and specifically relates to an optical measuring method and apparatus for deformation and strain of a high speed rotating structural member. The optical measuring apparatus comprises a high speed rotating system for a thin disk-shaped axisymmetric structural member, an image acquisition and signal processing system and an auxiliary test system, wherein the surface of a test member of the thin disk-shaped axisymmetric structure is coated with a pattern of concentric circles and a vertical ultra high-speed rotating axis is formed; a disk type variable frequency motor is used to drive the single-point supported vertical ultra high-speed rotating axis in a vacuum chamber; a common low-speed digital camera is used to acquire the surface pattern of concentric circles of the high-speed rotating thin disc-shaped axisymmetric structure test member under the irradiation of a stroboscopic light source; and the image identification technology is used to acquire the pattern change information and obtain deformation and strain of the high speed rotating test member after processing the pattern change information. The optical measuring method and apparatus for deformation and strain of a high speed rotating structural member can acquire the stress information by measuring changes of the radius of the concentric circles, and are suitable for the mechanical robustness testing field of high speed and ultra high-speed rotating structural member, wherein the rotating speed is greater than 10000rpm.
Owner:TSINGHUA UNIV

In-situ heating mechanical sample rod

An embodiment of the invention relates to the technical field of high-temperature micro-nano experimental mechanics, and provides an in-situ heating mechanical sample rod, which comprises a sample rodbody, a tilting table, a driving module and an in-situ mechanical-thermal coupling microelectromechanical system used for realizing stretch, compression and heating functions of a sample, wherein a linear stepping motor and a driving rod are arranged in the sample rod body, and a connecting part of the tilting table is rotationally connected to the sample rod body; the linear stepping motor is connected to the driving rod for enabling the driving rod to carry out reciprocating rectilinear motion along the length direction of the sample rod body in order to realize the rotation of a mounting part of the tilting table; the driving module comprises a driver stage and a driver; the driver stage is arranged on the mounting part of the tilting table; and the driver is arranged on the driver stage, and the action end of the driver is connected to the in-situ mechanical-thermal coupling microelectromechanical system. According to the in-situ heating mechanical sample rod, the stress is applied in situ while the temperature of the sample is adjusted in order to study the mechanical states and properties of the sample at different temperature.
Owner:BEIJING UNIV OF TECH

Half sub region relevant optical measurement method of strain field in strain localization zone

The invention provides a half sub region relevant optical measurement method of a strain field in a strain localization zone. An image of one surface of an object in a loaded process is collected; the displacement and the strain of each measuring point on the image and the inclination angle of the strain localization zone to be measured are obtained; two parallel measuring lines are arranged in the normal direction of the strain localization zone to be measured; a plurality of measuring points are arranged; the coordinates and the displacement of the measuring points simultaneously positioned on the measuring line and the starting boundary line of the strain localization zone to be measured are obtained; the coordinates and the displacement of the measuring points with the distance being a half of the distance of the measuring lines are determined inside and outside the strain localization zone to be measured; the strain of a rectangular pixel block is calculated; the distribution rule of the strain field inside the strain localization zone to be measured is obtained. The time-space distribution rule of the strain field in the strain localization zone can be better measured; the strain distribution in the strain localization zone obtained through measurement is smooth, continuous and accurate; the measurement precision of the inside strain field in the strain localization zone is improved; the wide application is realized in the field of solid experimental mechanics.
Owner:LIAONING TECHNICAL UNIVERSITY

Non-contact detection method for leakage of gas with temperature higher than environment temperature

The invention relates to a non-contact detection method for the leakage of gas with a temperature higher than an environment temperature, belonging to the technical fields of experimental mechanics and gas seal measurement. The non-contact detection method comprises the following steps: photographing a whole-field image of a to-be-detected region in real time by virtue of an infrared thermal imager to obtain a group of infrared images, so as to obtain corresponding temperature fields; carrying out temperature gradient operation on the obtained temperature fields, so as to obtain a temperature gradient; and processing the images by combining a heat conduction theory with an infrared image processing algorithm, so as to obtain a gas leakage position and a leakage rate. The position and the leakage rate during the leakage of gas with the temperature higher than the environment temperature are measured based on an infrared thermal imaging technique, an image processing theory and the heat conduction theory, so that the precise location of the leakage position and the quantitative measurement of the leakage amount can be simultaneously realized; and the non-contact detection method is wide in applicability, is not limited in certain specific gas and has the characteristics of high detection sensitivity, anti-jamming capability and the like.
Owner:TSINGHUA UNIV

Optical measurement method for strain rate field inside object with parallel front and back surfaces

The invention discloses an optical measurement method for a stain rate field inside an objected with parallel front and back surfaces.The method comprises the steps that velocity fields of measuring points on the front and back surfaces of the loaded object with the parallel front and back surfaces are obtained through a digital image relative method at first; the object with the parallel front and back surfaces is divided into gap-free voxel cuboids which are arranged in rows and columns without being stacked and with measuring points are top points, each voxel cuboid is simplified into a hollow voxel cuboid formed by four voxel tetrahedrons, the measuring points on the front and back surfaces are the top points of the voxel tetrahedrons, and the stain rate of each voxel tetrahedron is calculated based on the velocity field of the top point of the voxel tetrahedron; the stain rates of the voxel cuboids are calculated based on the stain rates of the voxel tetrahedrons, and then the stain rate field inside the object with the parallel front and back surfaces is obtained.The optical measurement method is simple in calculation, has the advantages of being high in measurement precision and low in measurement condition, has the wide application prospect in the field of solid experimental mechanics, and is of great benefit to preventing landslide, rockburst and other disasters.
Owner:LIAONING TECHNICAL UNIVERSITY

In-situ high-temperature quantitative mechanical experiment table for transmission electron microscope

The embodiment of the invention relates to the technical field of material in-situ micro-nano experimental mechanics, and provides an in-situ high-temperature quantitative mechanical experiment tablefor a transmission electron microscope. The in-situ high-temperature quantitative mechanical experiment table comprises a sample rod body, a tilting table, a driving module and a micro-electromechanical system integrated testing device for acquiring the stress-strain information of a sample under temperature-stress coupling conditions; a linear stepping motor and a driving rod are arranged in thesample rod body, and the connecting part of the tilting table is rotatably connected with the sample rod body; the linear stepping motor is connected with the driving rod and is used for enabling thedriving rod to do reciprocating linear motion along the length direction of the sample rod body, so that the mounting part of the tilting table can rotate; and the driving module is arranged on the mounting part of the tilting table and is used for carrying out mechanical loading on a sample on the micro-electromechanical system integrated testing device. The in-situ high-temperature quantitativemechanical experiment table for the transmission electron microscope can realize quantitative high-temperature mechanical test on micro-nano scale samples, and obtains an optimal observation angle inreal time through double-shaft tilting.
Owner:BEIJING UNIV OF TECH

Experimental apparatus and method for measuring poisson ratio of material under high temperature

InactiveCN102980813AHigh measurement temperatureOvercome the disadvantages of more cumbersome proceduresMaterial strength using tensile/compressive forcesExperimental methodsHigh temperature electronics
The invention discloses an experimental apparatus and method for measuring a poisson ratio of a material under high temperature, belonging to the technical field of experimental mechanics and high-temperature tests. The experimental apparatus and method adopts a method combining high-temperature electronic speckling and four-point phase bending to measure the poisson ratio of the material under the high temperature, and is in particular applicable to measuring the poisson ratio of the material under the ultra-temperature (more than 1600 DEG C). The experimental method comprises the steps of: recording interference speckle fields generated by object light and reference light by adopting non-contact measurement and a CCD (Charge Coupled Device) after a four-point bent sample is irradiated by laser, and measuring the off-plane displacement before and after the four-point bending of the sample by adopting an electronic speckling technology, thus directly obtaining the poisson ratio of the material under the high temperature according to a bar chart of the off-plane displacement, so that a problem that the poisson ratio of the material under the high temperature is difficultly measured can be solved.
Owner:TSINGHUA UNIV

Buckling test method and device for quantitatively characterizing interfacial bonding properties of thin film materials

The invention relates to a flexure testing method and a flexure testing device for quantitatively characterizing the interface binding property of thin-film material and belongs to the technical field of property characterization of experimental mechanics and material mechanics. The method is characterized in that uniaxial compression is performed to a sample in the axial direction through a universal material testing machine, and the stress strain values of the sample are recorded; meanwhile, the cross section of the sample is observed synchronously in real time through a CCD camera during the loading process, and stripping characteristics such as critical stress, deflexion and crack length can be recorded in real time during the flexure process; and a relation between the coating and plating-substrate stress strain history and the stripping characteristics is established to characterizing the interface binding property of the coating and plating-substrate. According to the device, the CCD camera, a monitor, an image processing card, a computer, a data processing card, a load sensor and the universal material testing machine are connected in sequence. The invention has the advantages of simple principle, simplicity in sample preparation, clear model, easiness in operation, and the like.
Owner:XIANGTAN UNIV

Experiment method for measuring asynchronous curing degree distribution of transparent resin material

The invention belongs to the technical field of experimental mechanics and non-contact optical measurement, and relates to an experiment method for measuring asynchronous curing degree distribution of a transparent resin material. By the adoption of the coherent gradient sensing method, curing degree distribution of the transparent resin material is measured in real time. According to the method, firstly, the transparent material is contained in a transparent container before curing; then, the container is placed in a heating furnace, wherein the front and the back of the heating furnace are provided with windows; then, the heating furnace is placed in a coherent gradient sensing measurement optical path, interference fringes caused by change of the curing degree of the material are shot in real time through a CCD camera, and accordingly relevant information of curing degree distribution of the material is obtained. The adopted coherent gradient sensing technology is optical non-contact measurement. Compared with a traditional DSC method, the measured material does not need to be contacted, interference on curing of the measured material is reduced, and asynchronous curing can be monitored globally.
Owner:AVIC BEIJING INST OF AERONAUTICAL MATERIALS

Testing method and testing system of effective stress of polyethylene under ideal non-damage state

ActiveCN109187186AEasy to implementOvercoming the limitations of the sample size rangeMaterial strength using tensile/compressive forcesEngineeringExperimental mechanics
The invention discloses a testing method and a testing system of effective stress of polyethylene under an ideal non-damage state. The method comprises the following steps: quantificationally introducing polyethylene material damage through a tensile testing machine; testing a damage parameter of the polyethylene material according to the damage, and consequently determining effective stress underthe ideal non-damage state. The method and the system provided by the invention has the advantages of being simple to realize, introducing the polyethylene material damage through the tensile testingmachine, testing the damage parameter of the polyethylene material according to the damage and consequently determining the effective stress under the non-damage state. Limit to a range of sampling size in the conventional microscopic damage test method is overcome, and dependence on a microscopic technology with high precision, complex operations and high cost is avoided. A defect of being not suitable for the polyethylene of the conventional method is remedied, a polyethylene material damage and failure mechanism and evolution law research especially suitable for the polyethylene material is used, and reliable method support can be provided for polyethylene damage and fracture representation and calculation simulation in the fields, such as experimental mechanics and numerical simulation.
Owner:CHINA UNIV OF PETROLEUM (EAST CHINA)
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