442 results about "Stress measurement" patented technology

A method for producing a substantially calibrated numerical model, which can be used for calculating a stress on any point in a formation, accounts for a formation's geologic history using at least one virtual formation condition to effectively “create” the present-day, virgin stress distribution that correlates, within acceptable deviation limits, to actual field stress measurement data obtained for the formation. A virtual formation condition may describe an elastic rock property (e.g., Poisson ratio, Young's modulus), a plastic rock property (e.g., friction angle, cohesion) and/or a geologic process (e.g., tectonics, erosion) considered pertinent to developing a stratigraphic model suitable for performing the desired stress analysis of the formation.

The invention provides a method for carrying out ultrasonic inspection on residual stress of an aluminium alloy pre-stretching board by water immersion, belonging to the field of non-destructive inspection. The method comprises the following steps of preparing a reference block; carrying out measurement and calibration; measuring the residual stress. In the method, the water immersion method is adopted, and the temperatures in stress calibration and stress measurement processes can be ensured to be consistent by controlling the water temperature not to be changed, thus eliminating the effects of temperature difference on the ultrasonic wave speed and eliminating temperature errors; besides, an automatic scanning frame is adopted instead of manual scanning, so that the distance between a probe and the surface of a material to be measured in the measurement process can be ensured not to be changed, thus eliminating the effects of coupling condition difference on sound propagation time and eliminating the coupling errors. The method is beneficial to non-destructive evaluation of the near surface residual stress of the aluminium alloy pre-stretching board.

The invention discloses a device for measuring object stress by utilizing a graphene membrane, and a preparation method and a testing method of the device. The testing method is characterized in that graphene is arranged on a flexible stretchable substrate by utilizing a growth and transfer technology of the graphene and is tightly adhered to the surface of a to-be-measured object or a single crystal silicon substrate which is provided with a through hole, a characteristic peak of a Raman spectrum of the graphene can be subjected to shifting and splitting when the to-be-measured object is subjected to deformation or gas pressure difference exists between the internal part and the external part of the through hole, and sensing on strain or gas pressure can be realized basing on shifting and splitting amount of the characteristic peak. According to the device, the preparation method and the testing method, disclosed by the invention, the technical design is simple, the performance is stable, non-contact with the to-be-measured object is realized, and the complexity of an electrical measurement method which is in need of arranging leading wires can be avoided; the strain loading range is large, and the stress measurement accuracy degree is high.

The invention relates to a welding structure residual stress ultrasonic lossless measurement device and a method, in particular to a device and a method using ultrasonic for measuring the residual stress of a welding structure, belonging to the residual stress measurement field. The method aims at overcoming the problems of a traditional stress measurement method that work pieces are destroyed, time is consumed and the residual stress measurement can not be satisfied under the service condition of the welding structure. The two ends of a probe group of the invention are respectively connected with an impulse signal source and a signal receiving processing device which is connected with a display. And a microcontroller is embedded in the signal receiving processing device. In said method, the coordinate of a measured point is determined; the probe group emits impulse signals sent out from the impulse signal source into a work piece through a first critical refraction angle to generate critically refracted longitudinal waves, wherein, enveloping data are read by the signal receiving processing device and are discretized into digital signals and FIR filtering waves; total enveloping weight eigenvalue Mn is worked out; abnormal data are removed according to Brubbs criterion after one measured point is measured for a plurality of times, measuring position is changed for measuring again, and Mn and Mn+1 are worked out according to two measuring points to calculate the residual stress Delta of the work piece.

A method for preparing calibration test sample of X ray stress measurement includes removing phenomenon of crystal particle coarsening and crystal face preferred orientation, carrying out short blasting treatment for semiproduct of the sample, stripping layer by layer for portion with greater stress gradient by electrochemical corrosion, carrying out X ray stress measurement and calibrating out work surface of the sample by utilizing relation curve of stress to layer depth.

The invention discloses an effective stress level test device and method of a vertical prestressed reinforcement. An ARM (Advanced RISC Machines) processor is connected with an ultrasonic pulse generator; a pulse signal emitted from the ultrasonic pulse generator is transmitted to an ultrasonic transducer via a boosted circuit and a transmitter circuit; the ultrasonic transducer transmits the ultrasonic wave to a data register via a programmable filter, a programmable amplifier and an A/D (analog-to-digital) converter; collected signals are sent to a DSP (Digital Signal Processor) by the data register; the DSP stores the signals in an RAM (Random-Access Memory) storage area; the ARM processor is connected with a memory, a keyboard, a display, the programmable amplifier, the programmable filter, the RAM storage area and a temperature measurement circuit; and the temperature measurement circuit is connected with a temperature sensor. The device has the characteristics of no loss, high speed, high accuracy and low cost, especially can quantify the influence of temperature on a stress measurement result, can correct the stress level test error of the vertical prestressed reinforcement so as to obtain the effective stress level value of the vertical prestressed reinforcement with the engineering accuracy.

The invention relates to a surface residual stress ultrasonic detection method capable of achieving direct coupling wave generation, and belongs to the technical filed of ultrasonic detection. According to the method, a wave generation mode of coupling agent direct coupling is adopted, ultrasonic waves pass through a single coupling agent medium and directly emit into a measured material, and an adopted direct coupling wave generation ultrasonic probe is in a one-emitting double-receiving stress measurement mode. Firstly, the direct coupling wave generation ultrasonic probe is designed and assembled, the assembled direct coupling wave generation ultrasonic probe is placed on the surface of the measured material, and the measurement cardinal plane is kept in full contact with the surface. A coupling agent is stably injected into a coupling agent cavity from a valve opening, an ultrasonic wave direct spreading passageway is formed, and surface residual stress ultrasonic detection is carried out. According to the method, wave generation and coupling are completed at the same time, fewer ultrasonic wave spreading interfaces exist, the quality of received signals is guaranteed, and the signal to noise ratio is increased. According to the adopted stress measurement mode, transit time difference calculation precision is guaranteed, and the measurement spatial resolution is improved.

In a method for producing epitaxially coated semiconductor wafers, a multiplicity of prepared, front side-polished semiconductor wafers are successively coated individually with an epitaxial layer on their polished front sides at temperatures of 800-1200° C. in a reactor, while supporting the prepared semiconductor wafer over a susceptor having a gas-permeable structure, on a ring placed on the susceptor which acts as a thermal buffer between the susceptor and the supported semiconductor wafer, the semiconductor wafer resting on the ring, and its backside facing but not contacting the susceptor, so that gaseous substances are delivered from a region over the backside of the semiconductor wafer by gas diffusion through the susceptor into a region over the backside of the susceptor, the semiconductor wafer contacting the ring only in an edge region of its backside, wherein no stresses measurable by means of photoelastic stress measurement (“SIRD”) occur in the semiconductor wafer.

The invention discloses a method for determining the three-dimensional stress based on single drilled rock's deformation measurement, comprising: A) constructing a horizontal testing hole: smoothening the hole bottom center of the testing hole; B) performing hole bottom stress removing work: installing a quadruple-component strain cluster on the already smoothened hole bottom of the testing hole to obtain the positive strain change values in different directions; C) performing partial wall face stress removing work: selecting a partial wall face from the side of the drilled hole away from the hole bottom for polishing process and obtaining two groups of hole wall positive strain values in eight directions after the measurement; and D) organizing and analyzing the data: in combination with the positive strain change values in different directions obtained from the stress removing work on the hole bottom and the side wall face of the testing hole, obtaining the three-dimensional stress state of a measurement spot. According to the method, it is possible to ensure that the stress measurement work at a measurement spot is completed in a relatively small rock scope, which avoids the influence of the heterogeneous factors of the rock characteristics on the measurement result, therefore, increasing the reliability of the measurement result.

The invention belongs to the technical field of building construction stress testing equipment, and relates to a pile body stress testing device of a static-pressure high-strength pre-stress concrete pipe pile. A shallow groove is formed in the high-strength pre-stress concrete pipe pile in a cutting mode, an optical fiber Bragg grating sensor and an armored cable are in butt fusion and in series connection in a quasi-distributed mode, the optical fiber Bragg grating sensor and the armored cable which are in series connection are implanted into the shallow groove of the high-strength pre-stress concrete pipe pile and packaged and protected through epoxy resin mixed liquid, the optical fiber Bragg grating sensor is distributed at the position of the high-strength pre-stress concrete pipe pile according to the elevation of a soil layer needing to be tested, a pile body drilling hole is formed in the inner side of the top of the high-strength pre-stress concrete pipe pile, and the armoured cable is led out through the pile body drilling hole and is communicated with a data collecting system. The device is simple in structure, convenient to operate, high in measurement precision and sensitivity, strong in the capacity of resisting electromagnetic field interference and high in survival rate; compared with a traditional stress measurement element, the pile body stress testing device can easily achieve quasi-distributed and automatic monitoring.

The invention discloses a brittle material crack initiation stress measurement system and a brittle material crack initiation stress measurement method. The brittle material crack initiation stress measurement system comprises a loading device, a CCD camera, a synchronizer trigger, a load-time signal receiving device and a digital image signal receiving device. The brittle material crack initiation stress measurement method includes synchronously triggering the loading device and the CCD camera by the synchronizer trigger, loading a sample and outputting a load-time signal; shooting sample surface images by the CCD camera in real time; not stopping shooting until the sample is destroyed; selecting a first frame of images shot by the CCD camera, marking 2 measurement points on the circumference of a through hole, continuously measuring tensile strain-time curves of the 2 measurement points in a whole loading process, and determining stress values, namely crack initiation stress sigmaci,on the stress-time curves corresponding to tensile crack initiation time T. The brittle material crack initiation stress measurement system and the brittle material crack initiation stress measurement method have the advantages that the position and the expansion direction of brittle material crack initiation can be controlled, the crack initiation time and the crack initiation stress can be determined objectively, precisely and quantitatively, authenticity and reliability of brittle material crack initiation stress measurement are improved effectively, and the method simple to operate, reliable in result and objective in quantization is provided for measuring crack initiation stress of rock-like brittle materials with prefabricated holes under uniaxial compression.

Time of flight of sound t₀, t_n propagating through fixed one face to another of the object under zero load (σ₀) and changed applied load (σ_n) respectively are measured, then stress dependent coefficient α peculiar to material of the object can be obtained from above data and the equation determined beforehand α=f(Δt_n, σ_n) using stress dependent coefficient calculation circuit 12. Time of flight of sound t propagating through one face to another of the object 1 at the determined place under applied unknown load is measured next. Time of flight t_n, t₀ are measured by time of flight measurement system 11. This invention consists of the stress measurement method and the apparatus to calculate real stress caused in the practically equipped object using equation

σ=f(Δt, α)

determined beforehand based on time of flight t and stress dependent coefficient α mentioned above.

The invention discloses a distributed optical fiber stress temperature sensing device and a sensing method. The sensing device comprises a light source, a pulse modulator, a circulator, a coupler, a Raman light filter, a Brillouin light filter, a Raman light detector, a Brillouin light detector, a first amplifier, a second amplifier, a data collector, a data processor and a computer. Specific light penetrates the Raman light filter and the Brillouin light filter respectively; the data processor calculates stress information and temperature information respectively according to the information of the specific light. The distributed optical fiber stress temperature sensing device can measure temperature and stress simultaneously while guaranteeing the measuring performance, and can eliminate the influence of the temperature when the stress is measured, thus improving precise of stress measurement.

The invention provides an ultrasonic non-destructive testing method for measuring circumference residual stress at root, the method is suitable for the non-destructive measurement of residual stress at the gear root. An LCR (critically refracted longitudinal) wave which is most sensitive to the stress is motivated through the combination of an ultrasonic stress measurement system, an ultrasonic transducer and a wedge block, and the residue stress at the region is precisely computed by using acoustic time difference of the LCR wave for detecting whether the stress is near to the root. The method is capable of accurately, fast and non-destructively detecting the residue stress value.

The invention discloses an online measuring device for the high-temperature mechanical behavior of a multilayer film matrix structure, belonging to the technical fields of engineering materials, structural deformation and mechanical experiments. The device comprises an isolated wall, an optical system and a data processing and display system, wherein the isolated wall comprises an insulated wall, a heating rod, a transmission window, a thermocouple, a specimen tray and a temperature control panel; and the optical system comprises a laser, a beam expander, an optical reflector, an optical grating, a lens, a filtering screen, a CCD camera and a piezoelectric brake. Through reconstructing the prior heating furnace, the online measuring device combines heating equipment with optical equipment so as to realize stress measurement for the multilayer film matrix structure at a high temperature. Moreover, the online measuring device has compact structure, and can realize online realtime monitoring for the mechanical property changes of the multilayer film matrix structure during heating.

Provided are a stress analysis method and stress analysis equipment that enable a detailed stress measurement, by using both a photoelasticity measurement method and a stress measurement (mechanoluminescence measurement) which utilizes a mechanoluminescent substance to measure a stress state of an object. Physical quantities that are measurable include individual principal stress component and a principal stress direction. The photoelasticity measurement method alone cannot measure individual principal stress component values.

The invention provides a nondestructive testing method of residual stress of thermally grown oxide layers in thermal barrier coatings. The method comprises the following steps: a laser beam with a specific wavelength enters to the surface of a thermally grown oxide layer to be tested, and a fluorescence spectrum of a trace element Cr3+ in the thermally grown oxide layer of the thermal barrier coating is excited; a characteristic peak of the fluorescence spectrum of excited Cr3+ and a characteristic peak of a fluorescence spectrum of Cr3+ excited in a stress-free state are compared, and distribution of internal stress in the thermally grown oxide layer is calculated according to offset of the characteristic peak. The method can solve the technical problem that traditional stress detection methods are difficult to realize stress measurement of TGO (thermally grown oxide) layers; changes of internal stress of TGO layers before and after examinations in various conditions (such as thermal shock, constant temperature oxidation, heat cycle or high temperature plume flow thermal shock, etc.) of a coating sample can be detected without destroy of the sample itself, and experiment foundation is provided for researching service behaviors and failure mechanisms of coatings; feasibility of nondestructive test of TGO internal stress in the coating of a practical workpiece before and after service is provided.

The invention provides a stress measurement primary stress separation method and device based on an ultrasonic surface wave and belongs to methods and devices of measuring the surface stresses of materials. The separation device comprises an ultrasonic transducer, an ultrasonic pulse transmission receiver, a sampling processing system and an analysis system. The output end of the ultrasonic transducer is connected with the input end of the ultrasonic pulse transmission receiver. The output end of the ultrasonic pulse transmission receiver is connected with the input end of the sampling processing system. The output end of the sampling processing system is connected with the analysis system through a digital oscilloscope. The working stress and the residual stress on the surface of an object are measured through the surface wave. In addition, the principle stress separation method is provided. Replication experiments of two-dimension stress measurement achieve surface wave lossless detection of two-dimension plane stress, a demonstration objet is A3 steel, the engineering application value is high, the experiment precision is high, and the stress measurement principle stress separation method and device are suitable for engineering detection. Through the advantages of ultrasound, lossless detection can be conduced on the single-point multi-dimension stress at any position.

The invention provides a distributive stress measurement-based pipeline interior corrosion monitoring method, belonging to the technical field of optical fiber sensing. The monitoring method comprises the following steps: measuring circular and axial strain distribution on the surface of a metal pipeline by adopting an optical fiber monitoring network, and drawing a circular and axial strain cloud picture, and positioning the corrosion position and corrosion range according to the stress distribution on the surface of the metal pipeline; calculating the strain of a corrosion area through the measured circular and axial stress of the corrosion area, and judging whether the pipeline in the corrosion area is invalid according to the stress and strain. The monitoring method has the effects and benefits that the safety situations of the metal pipeline can be monitored in real time, the corrosion defects can be positioned to obtain corrosion range, and whether the pipeline is invalid can be directly judged according to the stress and strain of the pipeline; and the monitoring method has the advantages of being safe and reliable, high in measurement precision, and non-destructive to a structure.

The invention relates to a stress measuring method based on a dynamic photoelastic system. The method comprises that dark-field imaging is carried out, and a first light intensity value of a stress measuring point is obtained; bright field imaging is carried out, and a second light intensity value of the stress measuring point is obtained; dark compensation field imaging is carried out to obtain a third light intensity value of the stress measuring point; the phase difference of birefringence caused by stress is obtained on the basis of the first, second and third light intensity values; and on the basis of the phase difference, different stress values of the stress measuring point are calculated. A laser vibration meter is used to verify the accuracy of a result measured via the method; the measuring method which is a new rotation polarizer method is characterized by a simple optical system, simple operation and the accurate result; and the measuring method can serve as a brand new method to measure the internal stress of a transparent solid, and can be applied to small stress measurement.

The invention discloses a micro capacitance-type wall shear stress sensor and a manufacturing method of the micro capacitance-type wall shear stress sensor based on through silicon via (TSV) technology, and belongs to the technical field of sensors. The micro capacitance-type wall shear stress sensor comprises a floating unit anchor point 1, an elastic beam 2, a movable broach 3, a fixed broach 4, a fixed broach anchor point 5, a TSV lead 6, a floating unit 7, a sacrificial layer 8, a substrate layer 9 and a TSV electric insulation layer 10, and is manufactured through a micro machining process and a metal plating process. According to the micro capacitance-type wall shear stress sensor based on the TSV technology, the original lead bonding process is replaced by a back-surface lead process, so that the metal leas is prevented from being exposed in a flow filed to generate interference. The packaging size of the sensor is reduced, arraying of the sensor is benefited, and three-dimensional (3D) packaging of the sensor and an integrated circuit is benefited. A measurement device does not invade in the flow field, so that no-invasion-type wall shear stress measurement can be carried out on the flow field.

The invention discloses a fiber grating type six-way pressure sensor for deep soft rock stress measurement, including a solid sphere provided with six pressure sensing unit mounting slots and a cylindrical optical fiber slot. A fiber grating pressure sensing unit is mounted in the pressure sensing unit mounting slots. Optical fibers connected with the fiber grating pressure sensing unit are converged in the cylindrical optical fiber slot along optical fiber wiring slots arranged in the outer surface of the solid sphere. A spherical shell covering the solid sphere from the outside is provided with a cylindrical outlet hole at a position corresponding to the position of the cylindrical optical fiber slot and is provided with cylindrical mounting holes at the positions corresponding to the positions of the pressure sensing unit mounting slots. The pressure sensor is applicable to deep soft rock geostress measurement. Based on the working characteristics of optical signal transmission, the pressure sensor has the advantages of satisfying the essential safety requirements of deep coal mine stress monitoring, is not affected by electromagnetic interference, has good long-term stability, and can realize real-time monitoring of the rock stress state.

The present invention relates to a developing method using a developing device including at least: a first developer bearing member arranged to be opposed to an image bearing member; and a second developer bearing member arranged on a downstream side of a rotation direction of the image bearing member with respect to the first developer bearing member, the developing method including developing a latent image formed on the image bearing member with a developer, in which: the developer is a two-component developer having toner and a magnetic carrier; and the developer has a degree of compression C in the range of 20 to 32% and a shearing stress obtained by shearing stress measurement under a consolidation load of 4.0×10⁻⁴ N/mm² in the range of 0.5×10⁻⁴ to 2.5×10⁻⁴ N/mm².