68 results about "Photoelasticity" patented technology

The invention belongs to the technical field of digital holographic measurement, and particularly relates to an optical element stress measurement and defect identification method based on a digital holographic photoelastic method. The method is realized based on a transmission-type off-axis digital holographic light path system; light beams emitted by the laser assembly are divided into reference light and object light, the object light is reflected by the surface of a sample and carries sample information, the object light and the reference light intersect in front of the CMOS camera to generate interference, the CMOS converts an interference light intensity signal into an electric signal, and holographic image processing is performed by the computer; the hologram before and after external force loading is reconstructed to obtain surface topography distribution, and the reconstruction precision is improved through the steps of positive first-order spectrum extraction, angular spectrum reconstruction automatic focusing and the like; the phase difference before and after external force loading is calculated through reconstruction complex amplitude phase extraction, and then the direction and size distribution of the principal stress of the sample are measured and calculated based on a digital photoelastic method and a stress optical law; and the defect of the optical element is identified by measuring the stress value change under the same external force loading, so that the method has important practical significance.

The invention discloses a power transmission crimping fitting crimping quality analysis method, which comprises the following steps: acquiring surface and internal characteristic data of a crimping fitting by using an ultrasonic imaging technology, and monitoring key parameters including pressure, temperature and displacement in a crimping process through a real-time sensor; performing comprehensive analysis on surface defects, heat distribution and internal structure characteristics of the crimping fitting through an artificial intelligence model in combination with the collected multi-modal data; a photoelastic analysis technology is adopted to detect residual stress distribution of a crimping area, and working parameters of the detection device are adaptively adjusted according to temperature, humidity and illumination changes of a detection environment. According to the invention, the quality analysis capability of the crimping fitting is improved from multiple aspects of accuracy, real-time performance, adaptability and the like, and a technical guarantee is provided for safe operation of a power transmission line.

Methods include driving a photoelastic modulator optical element with at least two transducers and controlling a phase difference between driving signals applied to the at least two transducers based on a variation in resonant frequency of the photoelastic modulator optical element and a variation in vibrational phase delay associated with a change in temperature of the photoelastic modulator optical element. Related system and apparatus are also disclosed.

There has been a demand for an optical film having excellent glass-range photoelastic coefficient and a polarizing plate which uses this optical film. The present invention provides an optical film which is characterized by containing an ester-based resin that contains 50% by mole or more of a fumaric acid ester residue unit represented by formula (1) and having a negative birefringence, and a photoelasticity regulator having a positive birefringence, and which is also characterized in that the absolute value of the glass-range photoelastic coefficient thereof is 5×10−12 Pa−1 or less.(In the formula, each of R1 and R2 independently represents a linear alkyl group having 1 to 12 carbon atoms, a branched alkyl group having 3 to 12 carbon atoms, or a cyclic alkyl group having 3 to 6 carbon atoms.)

The first purpose of the present invention is to provide a polycarbonate resin having excellent fluidity and small orientation birefringence. The second purpose of the present invention is to further provide, on the basis of the first purpose, a polycarbonate resin having a high Abbe number, a small orientation birefringence, and a small photoelastic coefficient. The third purpose of the present invention is to further provide, on the basis of the first purpose, a polycarbonate resin having a small orientation birefringence, a high refractive index, and a high glass transition temperature. The polycarbonate resin contains units represented by formula (1) and / or formula (2) and units represented by formula (3), and has a weight-average molecular weight Mw of 10,000-55000. (In formula (3), R1-R4 each independently represents a hydrogen atom or a hydrocarbon group having 1-10 carbon atoms)

The invention relates to the technical field of rock blasting fracture mechanics, in particular to a blasting crack tip stress intensity factor calculation method and system.The method comprises the steps that first information and second information are obtained, the first information comprises the wave velocity of longitudinal waves and the wave velocity of transverse waves in a dynamic optical measurement mechanics experiment, and the second information comprises the instantaneous velocity of crack propagation; optimizing a stress intensity factor calculation formula of the crack tip according to the first information and the second information to obtain an optimized calculation formula; obtaining experimental data in a dynamic optical measurement mechanics experiment; and determining the crack tip stress intensity factor of the detonation crack according to the optimized calculation formula and experimental data in a dynamic optical measurement mechanics experiment. Compared with a conventional calculation method for the crack tip stress intensity factor of the detonation crack, the method has the advantages that a crack propagation instantaneous speed parameter is introduced; the influence of speed change on crack tip stress intensity factor calculation is considered, and the accuracy of a crack tip stress intensity factor calculation result is improved.

The invention discloses an offshore wind power basic equipment stress monitoring and early warning system based on deep learning. The system comprises a data acquisition module, a mapping module, a stripe image prediction module, a fusion module, a model construction module, a stress module and an early warning module. According to the invention, the obtained multi-dimensional monitoring data is converted into a first stripe image which is consistent with a photoelastic stripe image in time and space through a mapping module and a stripe image prediction module, and then after the first stripe image and the photoelastic stripe image are fused, the stress distribution condition of the offshore wind power foundation equipment is predicted by using a stress module. And identifying abnormal characteristics in the stress distribution diagram, and in combination with a safety threshold value, judging potential risks in advance and sending out early warning. According to the method, the first stripe image and the photoelastic stripe image in the same time and space are fused to complement information loss of the first stripe image and the photoelastic stripe image, the fused image enables the stress prediction model to capture more key clues related to stress distribution at the same time, and the stress distribution can be predicted more accurately.

This invention provides a method and apparatus for photoelastic stress reconstruction based on physically constrained deep learning, relating to the fields of experimental mechanics and optical mechanics. The method involves acquiring images of the interference fringe state of a transparent specimen under load to obtain multi-channel tensor input data; using a physically enhanced convolutional neural network model for feature extraction and processing, and performing differential calculations to obtain full-field stress component output data; visualizing and rendering the full-field stress component output data to obtain reconstructed visual data; comparing the full-field stress component output data with reference benchmark data, calculating error indices, and recording process time to obtain accuracy and efficiency evaluation data; and simultaneously integrating and displaying the reconstructed visual data and the accuracy and efficiency evaluation data to obtain a comprehensive evaluation and reconstruction result. This invention solves the inherent limitations of traditional phase unwrapping and stress separation techniques.

Aspects of the present disclosure describe integrated optics-based phase controllers that include a waveguide having a core with one or more cavities whereby it can exhibit enhanced photoelastic effects and / or increased stress-induced deformation in at least one zone. The waveguides according to the present disclosure are particularly useful in stress optical phase controllers that are suitable for systems such as microwave photonics, LiDAR, and the like.

The invention discloses a temperature-controlled re-icing photoelasticity test device and a method thereof, belongs to the technical field of re-icing tests, and provides the following scheme that the temperature-controlled re-icing photoelasticity test device comprises a re-icing test mechanism, a loading mechanism is assembled on the re-icing test mechanism, and the re-icing test mechanism comprises a base, a camera, an analyzer, a polarizer, a light source and two bearing platforms; a transmission assembly is lifted through a loading assembly, so that the transmission assembly and a second gear are in transmission, the second gear drives an annular frame to move through a crankshaft, the annular frame drives a first sliding sleeve and a roller rod to move, a second spring drives a first scraping plate to reset, the first scraping plate passes through the surface of a lower clamp, and the first sliding sleeve drives a second sliding rod to move; and a third spring drives a second scraping plate to reset, the second scraping plate passes through the position below the upper clamp, the first scraping plate and the second scraping plate can play a cleaning role on the lower clamp and the upper clamp, residues of water and broken ice blocks on the upper clamp and the lower clamp are reduced, and therefore the next round of test operation can be conveniently carried out.

The invention relates to the technical field of residual stress detection of insulating parts, in particular to a photoelastic detection system and a photoelastic detection method for residual stress of an epoxy resin insulating part, which are used for performing non-destructive detection on residual stress at a metal-epoxy resin interface on a cured and molded epoxy resin insulating part containing a metal insert. Comprising a preparation unit used for processing epoxy resin materials, a photoelastic observation unit used for obtaining stripe images and load data and a data processing unit used for calculating photoelastic parameters and interface residual stress, and the preparation unit comprises a polytetrafluoroethylene mold, a vacuum defoaming device and an oven. The photoelastic observation unit comprises a light source module, a light path adjusting module, a stress application module and an image acquisition module, and the data processing unit comprises a computer. The method realizes non-destructive, quantitative and high-precision detection of the residual stress of the metal insert-epoxy resin interface, and has the characteristics of simplicity and convenience in operation, low cost and adaptability to an engineering site.

A method for measuring residual stress of a silicon wafer (1), comprising: when a silicon wafer (1) undergoing measurement is in a first physical state, separately emitting polarized light beams (A) in the radial direction and the circumferential direction of said silicon wafer towards the surface of said silicon wafer, and obtaining a first optical path difference between the polarized light beam in the radial direction and the polarized light beam in the circumferential direction; when said silicon wafer (1) is in a second physical state, separately emitting polarized light beams (A) in the radial direction and the circumferential direction of said silicon wafer (1) towards the surface of said silicon wafer (1), and obtaining a second optical path difference between the polarized light beam in the radial direction and the polarized light beam in the circumferential direction; on the basis of the first optical path difference, a first proportional relationship between the first optical path difference and the photoelastic coefficient of said silicon wafer (1), the second optical path difference, and a second proportional relationship between the second optical path difference and the photoelastic coefficient, obtaining the photoelastic coefficient; and on the basis of the photoelastic coefficient and the first proportional relationship, obtaining the residual stress of said silicon wafer (1). Further provided are a system for measuring residual stress of a silicon wafer (1) and a corresponding silicon wafer (1).

The invention belongs to the technical field of photoelectric materials and application, and discloses a main chain conjugated intrinsic stretchable thermal delay fluorescent elastomer as well as a preparation method and application thereof. The elastomer is prepared through free radical polymerization by taking a high-efficiency luminous TADF conjugated unit as a main chain and acrylic ester as a flexible side chain. The innovation of the invention lies in that a flexible acrylate side chain is introduced into a rigid efficient electroluminescent TADF conjugated main chain for the first time in a chemical cross-linking manner to form a rod-like bottle brush structure, so that the elastomer has good photoelectric characteristics on the basis of improving the intrinsic tensile property of the elastomer; the structure is novel, the design strategy is unique, and meanwhile the problems that a traditional conjugated luminescent material is not intrinsic in stretchability and a traditional elastomer does not have the high-performance photoelectric characteristic are solved; the elastomer is used as a luminescent layer material to prepare an organic photoelectric device with high stability, high stretchability and high efficiency.

An optical polymer material includes an alternating copolymer made of a monomer of a styrene derivative and a monomer of a maleimide derivative, and has a nonlinear property in which the photoelastic coefficient of the optical polymer material decreases to a predetermined value with increase in composition ratio of the styrene derivative, and rises above the predetermined value with further increase in composition ratio of the styrene derivative. A composition ratio of the styrene derivative is within a predetermined range. An absolute value of the photoelastic coefficient is equal to or smaller than a first absolute value within the predetermined range of the composition ratio, and an absolute value of the intrinsic birefringence is equal to or smaller than a second absolute value of the optical polymer material within the predetermined range of the composition ratio.

The present invention discloses a device and method for measuring the principal stress on the surface of a specimen, comprising: a photoelastic patch adhered to the component to be measured; and a measuring assembly disposed on one side of the component to be measured adhered with the photoelastic patch, including a light source, a color filter, a polarizer, a quarter-wave plate, an analyzer and a CCD detachably fixed on a platform. By moving the positions of some devices in the measuring assembly, the isochromatic fringe order and the strain value on the surface of the specimen are measured, and the principal stress on the surface of the specimen is obtained. The present invention can measure the full-field principal stress value on the surface of the specimen and can more intuitively display the stress distribution on the surface of the specimen in the form of photoelastic fringes.

The invention belongs to the technical field of mechanics teaching aids, and particularly discloses a portable simple photoelastic mechanics instrument for teaching, which comprises a photoelastic sample, and also comprises a sample mounting bracket, the upper end of the photoelastic sample is connected with the sample mounting bracket, and the front end and the rear end of the sample mounting bracket are through; the lever loading assembly is connected with the lower end of the photoelastic sample and is used for applying a load to the photoelastic sample; the polaroid assemblies are arranged on the front side and the rear side of the sample mounting bracket; the light source assembly is arranged on the outer side of the polaroid assembly and provides a light source. The white light source is used, so that the weight and the size of the instrument can be effectively reduced, the instrument is convenient to carry, lever loading is applied, loading visualization and visualization are achieved, light and dark stripes on the photoelastic sample are alternately arranged, small elastic deformation can be visually displayed, elastic deformation display visualization is achieved, cost is low, operation is easy and convenient, and popularization is facilitated.

To provide a cyclic olefin copolymer resin composition capable of: suppressing birefringence to an extremely small value even at a high-temperature range while suppressing any foreign matter such as white haze in molding or poor appearance; and obtaining an optical component with extremely small birefringence such as a lens even under not so severe mold conditions.SOLUTION: In this invention, provided is a resin composition comprising a cyclic olefin copolymer being a copolymer of ethylene or α-olefin and a cyclic olefin, which has: an absolute value of a photoelastic coefficient measured at 110°C of 10.0×10-12 Pa-1 or less; and a glass-transition temperature of 130°C or higher, and contains 0.5-2.8 mass% of a higher fatty acid ester.SELECTED DRAWING: None

The triaxial compression test device based on the photoelastic instrument comprises a light source and an imaging device, a photoelastic instrument main body is arranged between the light source and the imaging device, and the photoelastic instrument main body comprises a front polarization frame and a rear polarization frame which are respectively provided with a front polarizer and a rear polarizer; a test piece loading frame is arranged between the front polarization frame and the rear polarization frame, a downward pressing force application plate is arranged in the test piece loading frame, and a tension sensor is arranged below the downward pressing force application plate. The change of internal stress and a contact force chain of the particles is analyzed by observing the optical performance of the particles, a stress field of the particles is drawn, the rotation angle and the displacement field of the particles can be researched, the micro-mechanical characteristics in the particles are further analyzed, and macro-mechanical information and the micro-mechanical characteristics are combined for analysis; and the property change of the particles in the test process can be better studied.

The invention relates to chemically strengthened glass and a manufacturing method thereof. The present invention relates to a chemically strengthened glass having a thickness t [mm], in which, in the distribution of stress values CSx [MPa] at a depth x [[mu] m] from the glass surface of the chemically strengthened glass measured by a scattered light photoelastic stressometer, the value CSx "of the second order differential of the stress values CSx satisfies the following formula: 0 < CSx" < = 0.050 within the range CSx > = 0.

An object of the present application is to provide a phase difference film capable of producing an image display device in which unevenness in mounting is suppressed, and a polarizing plate and an image display device using the phase difference film. The phase difference film of the present application is a phase difference film having a support exhibiting a reverse wavelength dispersion in an in-plane retardation, and a liquid crystal layer directly laminated on the support, wherein the support is a polymer film subjected to a stretching treatment in at least one direction in the plane, the liquid crystal layer is a positive C-plate obtained by fixing the orientation state of a liquid crystal composition containing a liquid crystal compound, and the photoelastic constant of the support is 30 x 10 ‑12 or less.

The present invention provides a stress measurement device and method, which relate to the technical field of stress measurement. This scheme designs a combined reflection and transmission optical path based on the principle of photoelasticity. The reflection optical path can use a phase shift method to obtain the polarization characteristics of the flexible substrate layer. Combined with the known polarization characteristics of the flexible substrate layer, the transmission optical path can use a multi-step phase shift fitting method to obtain the polarization characteristics of the inorganic semiconductor layer. Then, through the dewrapping technology and stress separation technology, the full-field normal stress and shear stress of the flexible substrate layer and the inorganic semiconductor layer are respectively determined, and the full-field stress distribution image can be displayed in real time.

Fatigue-resistant photoelastic soft materials are provided for soft robots and other sensing applications. The fatigue-resistant photoelastic soft materials include hydroscopic salt that allow the stress-optical coefficient of the fatigue-resistant photoelastic soft material to be tuned. The fatigue-resistant photoelastic soft materials include molecular entanglements that help to tune mechanical properties of the fatigue-resistant photoelastic soft materials.

The invention discloses a crack propagation observation experiment device and method based on a photoelastic method. The device comprises a pumping system and a photoelastic optical platform, the pump injection system comprises a pump, a fracturing fluid container and a shaft which are connected in sequence; the photoelastic optical platform comprises a light source, a sample mold, a polaroid and a wave plate; the sample mold is placed above the shaft; the light source passes through the first polaroid and the second polaroid to form a dark field; the first wave plate is placed between the first polaroid and the second polaroid, and the angle of the first wave plate is determined by rotating the first wave plate; and placing a second wave plate between the first polaroid and the second polaroid, and rotating the second wave plate to form a dark field, thereby determining the positions and angles of the first polaroid, the second polaroid, the first wave plate and the second wave plate. According to the invention, the crack propagation in the oil and gas production process can be better simulated, and the related rule in the crack propagation process and the stress distribution around the crack can be accurately described.

The present invention discloses a micromechanics testing platform and method for granular materials based on optical measurement technology. The testing platform is equipped with, from left to right, a polarized light source, a polarizer, a biaxial loading device, an LED light source, an analyzer, and the image acquisition system. The optical platform is also equipped with a control system electrically connected to the biaxial loading device. Based on optical measurement technology, this micromechanics testing platform for granular materials achieves shearing of a two-dimensional dense particle system through the movement of an adjustable biaxial loading device. By rotating the analyzer, it can switch between polarized and unpolarized light fields to acquire test images under different light fields. Contact force and dynamics analysis is performed by combining photoelasticity and digital image correlation techniques. This micromechanics testing platform for granular materials utilizes high-precision, high-frequency image acquisition technology to intuitively and synchronously acquire contact force and dynamics information of granular materials without contact.

The invention discloses a photoelasticity-based defect detection method. The photoelasticity-based defect detection method comprises the following steps: arranging an object to be detected on a base; providing a laser device which comprises a collimator, a polarizer and a laser light source, and emitting a first laser beam towards the detection part of the object to be detected; providing a first photoelastic sensor, wherein the first photoelastic sensor receives first reflected light of the first laser beam reflected by the detection part of the to-be-detected object to generate a first reflected light signal, or receives first penetrating light of the first laser beam penetrating through the detection part of the to-be-detected object to generate a first penetrating light signal; an image device is provided and electrically connected with the first photoelastic sensor, and the image device receives the first reflected light signal or the first penetrating light signal and generates a first stress distribution characteristic pattern; therefore, the detection precision is improved. The invention also provides a photoelasticity-based defect detection system.

The utility model discloses a transmission type photoelastic instrument multifunctional loading frame, which comprises a servo motor, an upper beam, a loading beam, a lower beam, stand columns and a base, the number of the stand columns is two, the two ends of the upper beam are fixed at the top ends of the two stand columns, the loading beam is assembled at the lower part of the upper beam, and the two ends of the loading beam are sleeved on the two stand columns through sleeves. The loading beam can move up and down along the two stand columns, the servo motor is fixed to the upper beam, the servo motor is connected with an output gear, the output gear is meshed with the transmission gear, the servo motor can drive the transmission gear to rotate through the output gear, and the upper portion of the ball screw is assembled in the middle of the top face of the upper beam. The device has the advantages that the device can be directly installed on a table top, and dynamic balance of force values in the experiment process is achieved. The loading mode is high in precision, stable in load and worthy of vigorous popularization.

Apparatus include an elastically deformable photoelastic modulator (PEM) assembly holder defining an interior volume sized to receive at least one transducer of a PEM assembly, wherein the PEM assembly includes the at least one transducer and a photoelastic optical element attached to the at least one transducer and wherein the at least one transducer has a plurality of holder contact surfaces, wherein the PEM assembly holder includes a plurality of receiving portions located on side walls facing the interior volume and corresponding to respective ones of the holder contact surfaces of the at least one transducer, each receiving portion being displaceable through deformation of the PEM assembly holder so that the at least one transducer is insertable in the interior volume and cushionably supported in a predetermined position with the receiving portions in contact with the respective holder contact surfaces and such that the photoelastic optical element does not contact the PEM assembly holder.

The application belongs to the technical field of ellipsometric accurate measuring device and method, and particularly relates to an ultrahigh-speed ellipsometric accurate measuring device and method based on single photoelasticity modulation self-feedback, wherein a polarizer, a quarter-wave plate and a measured sample are sequentially arranged in the light path direction of a light source, a photoelasticity modulator, a polarizer and a detector are sequentially arranged in the reflection light path of the measured sample, and the photoelasticity modulator is electrically connected with a photoelasticity modulator driving control and a multi-channel digital lock-in amplification circuit. The application carries out multi-frequency signal lock-in amplification on the photoelectric signal modulated by a single photoelasticity modulator, takes the photoelasticity modulator driving frequency as a reference, obtains the signal amplitude of one frequency multiplication, two frequency multiplications, three frequency multiplications and four frequency multiplications, combines theoretical calculation to obtain the modulation phase amplitude caused by the long-term working temperature influence and environmental influence of the two photoelasticity modulators, and further realizes the accurate measurement of the ellipsometric parameters Δ and Ψ of the measured sample.

The invention discloses a reconfigurable micro-computing spectrometer based on a photoelastic effect and a spectrum reconstruction method, and belongs to the technical field of spectrometers, a filtering part of the spectrometer is composed of a polaroid and a photoelastic plastic sheet, is integrated at the top of a CMOS image sensor, and is used for realizing snapshot spectrum acquisition; the spectrum reconstruction method comprises the following steps: acquiring a modulated spectrum modulation image under single exposure; establishing a corresponding relation between the spatial position and the spectrum modulation unit; demodulating the acquired two-dimensional spatial spectrum modulation image, and separating signal components corresponding to different spectrum modulation units; recovering the spectral distribution of the incident light by using the demodulated signal component in combination with a spectrum reconstruction algorithm; and the angle of the polaroid and the number and spatial distribution of the spectrum modulation units are adjusted to realize spectrum reconstruction optimization. Dependence on a complex micro-nano manufacturing process and special materials is avoided, a reconfigurable strategy is developed, and spectrum sensing performance is enhanced by optimizing modulation efficiency and the number of spectrum modulation units.

Provided is an injection molded light-guiding member including a substrate section, an input coupler for causing light from an image display element to enter the light-guiding member, two surfaces of a wave-guiding section that are opposite to each other and that guide incident light through repeated reflection, and an output coupler for extracting light toward an eye of an observer from a light-guiding body through any function among refraction, diffraction, and reflection of guided light, wherein an absolute value of a photoelastic coefficient is 10×10−12 Pa−1 or less, and a partial reflecting mirror that transmits a portion and reflects a remaining portion of light is formed at at least one surface among a total of three surfaces consisting of the two surfaces of the wave-guiding section and a surface of the output coupler.