575 results about "Crack initiation" patented technology

Ion exchangeable glasses having coefficients of thermal expansion (CTE) at least about 90×10⁻⁷ ° C.⁻¹. The glasses undergo rapid ion exchange, for example, in a molten KNO₃ salt bath to a depth of layer of greater than 30 microns in less than 2 hours at temperatures of 370° C. to 390° C. When ion-exchanged to a depth of layer between 30 to 50 microns, the glasses exhibit a Vickers median/radial crack initiation threshold exceeding 30 kilograms force (kgf). The glasses are fusion formable and, in some embodiments, compatible with zircon.

The invention relates to a system and method for a visualization fracturing simulation experiment. According to the technical scheme, the system comprises a visualization fracturing simulation experiment device, a pressure control module and a data acquisition module, wherein the visualization fracturing simulation experiment device is a square container, the pressure control module comprises a servo control injection pump, a confining pressure pump and the like, and the data acquisition module comprises a pressure data recorder and a high-definition high-frequency vidicon. Through combination of the visualization fracturing simulation experiment device and transparent specimens, crack initiation characteristics and expanding dynamic states of hydraulic fractures in interiors of the experiment specimens can be clearly known by researchers, and study of crack initiation mechanisms and expanding rules of the hydraulic fractures are deepened. According to the experiment method, crack initiation and expanding dynamic state videos of the fractures can be obtained, crack initiation and the expanding rules of the fractures can be clearly showed, storage of video data is simple, spreading is convenient, and the method can help the researchers to exchange experiment achievements across regions.

The invention discloses a coal and rock bore hydraulic fracture experimental apparatus, which comprises a sample device system, a confining pressure system, a fracture system, a sealing system and a monitoring system, wherein the sample device system comprises a sample cylinder, the bottom in the sample cylinder is provided with a screen drum of which the bottom is provided with a water outlet pipe, a sample is accommodated in the sample cylinder above the screen drum, and a simulated bore is formed in the sample; the confining pressure system comprises an air filling subsystem and a water filling subsystem; the fracture system comprises a fracture high-pressure water pump of which a water outlet is communicated with the simulated bore through a fracture pipeline; the sealing system comprises a sample cylinder sealing device and an experimental cylinder sealing device; and the monitoring system comprises an acoustic emission sensor arranged on an external wall of the sample cylinder. By the coal and rock bore hydraulic fracture experimental apparatus, a simulated experiment can be performed in a laboratory to investigate the change rules of crack initiation, expansion and extension in the hydraulic fracture process of a coal mine underground coal seam bore, and know a crack extending direction so as to guide field fracture; therefore, the fracture effect is greatly improved.

The invention discloses a device for simulating crack initiation and evaluating fissured flow under true triaxial stress and belongs to the field of fracture acidizing. The device disclosed by the invention comprises a rock core clamping system, a true triaxial stress loading system, an acid liquor and fracturing fluid injection system, a filtration capacity measuring system and a fracturing data acquisition and processing system, wherein the rock core clamping system is used for clamping a cubic rock core sample which has the side length of 100-300mm and a simulation wellbore is embedded inside the rock core sample; the true triaxial stress loading system is used for applying stresses on the rock core sample in an X axis direction, a Y axis direction and a Z axis direction, so as to simulate a true triaxial stress state of the rock core sample; the acid liquor and fracturing fluid injection system is used for injecting acid liquor and fracturing liquid into the simulation wellbore of the rock core sample, so that crack initiation is carried out on the rock core sample and a fracture extends to simulate the fracture acidizing process of the rock core sample; the filtration capacity measuring system is used for injecting saline water into the rock sample subjected to crack initiation, thus data representing filtration capacity of the fracture of the rock core sample are measured; and the fracturing data acquisition and processing system is used for acquiring data representing a simulated crack initiation process in the rock core sample and data representing the filtration capacity of the fracture in the rock core sample, processing the data and outputting a processing result.

In separation of sheet glass by making use of thermal strain, separated surfaces can be obtained to avoid the occurrence of glass chips and to have excellent linearity even in relatively thick sheet glass. After a score, which serves as a crack initiation point is engraved at a separation initiation point in sheet glass, the sheet glass is heated along an imaginary line of by a heating burner; the heated portion of the sheet glass with the imaginary line of separation set therein is locally cooled by a mist, which is produced by a cooling nozzle comprising a liquid-ejecting port disposed at a central portion thereof and a gas-ejecting port disposed around an outer periphery of the liquid-ejecting port, the liquid-ejecting port projecting farther than the gas-ejecting port; and a minute crack of the score is caused to propagate along the imaginary line of separation to form a crack required for separation of the sheet glass.

The invention discloses a time-dependent fatigue reliability analysis method based on bilinear cumulative damage. The method includes the steps that 1, the probability distribution type and statistical characteristic parameter of fatigue life data are determined; 2, the appropriate reference life is selected, and a bilinear cumulative damage physical model is built; 3, according to the bilinear cumulative damage physical model, a probability cumulative damage model is built; 4, according to the stress-strength interference theory, a time-dependent fatigue reliability model is built; 5, a reliability curve is drawn and compared with an experimental result; the characteristics of a crack initiation stage and a crack propagation stage in the fatigue failure process and the randomness in the damage accumulation process are comprehensively considered, the bilinear damage theory serves as a modeling base, the probability cumulative damage model is built, through the combination with the stress-strength interference theory, the time-dependent fatigue reliability model based on cumulative damage and critical damage is built, the time-varying characteristics of fatigue loading and the dynamic behavior of the damage accumulation process are reflected, and the reliability prediction in the whole fatigue life cycle is achieved.

The invention discloses a tight reservoir volume pressure crack network extension simulation and representation method. The method comprises the following steps of: firstly establishing a multi-crackstress interference-considered tight reservoir combined ground stress field calculation model by utilizing a displacement discontinuity method, mechanical mechanism analysis and crack initiation and extension criterions; aiming at a stress interference problem in volume pressure crack multi-crack extension process, establishing flow pressure drop distribution models, in primary and secondary cracks, of a fracturing fluid, so as to form a tight reservoir volume pressure crack horizontal well crack network extension theoretical model; and finally comprehensively analyzing influences, on volume pressure crack network structural morphology, of different factors, and defining a plurality of feature parameters to represent crack network structure morphology and attribute features. At last, the tight reservoir volume pressure crack network extension simulation and representation method is established. The tight reservoir volume pressure crack network extension simulation and representation method has the advantages of being comprehensive in model factor consideration, high in simulation effect and visual in result, and has a certain guiding significance for optimum design and efficient development of tight reservoir cracks.

The present invention provides spoke geometry for a non-pneumatic tire that is less prone to fatigue when used. In particular, the spoke geometry is provided with an optimized thickness profile over the length of the spoke. This optimization results in a reduction in the peak strain energy density levels in the spoke, thereby reducing the likelihood of crack initiation and propagation which in turn enhances the durability of the spoke and tire.

The invention relates to a tight reservoir horizontal well volume fracturing process. Data including in-situ stress magnitude and direction, horizontal well azimuth and length, reservoir Young moduli, a Poisson ratio, a well logging interpretation result and the like are collected and used as basic parameters for calculating induced stress needed for generation of complex cracks in tight reservoir horizontal well volume fracturing; according to reservoir physical characteristics, induced stress difference value variation conditions of three or more perforation clusters in the same fracturing segment according to different crack initiation sequences are contrasted, and preference is given to the perforation cluster crack initiation sequences with the maximal induced stress difference value as the target; preference is given to perforation cluster gaps so that the complex cracks can be formed through fracturing in the same fracturing segment of a horizontal well; in cooperation with perforation parameter optimization and with bottom hole pressure control as the target, the effect that the cracks of the perforation clusters at the two ends are initiated and extended for a certain distance through discharge capacity adjustment and then the discharge capacity is improved to utilize perforation friction for pressing open the cracks of the perforation clusters in the middle is achieved; then, prepad fluid and sand-carrying fluid containing a propping agent are poured into the cracks in sequence to realize transformation of the shape of the complex cracks of the fractured horizontal well.

Methods and systems of predicting fatigue life in aluminum castings that combines extreme values of both casting flaws and microstructures with multiscale life models. The multiscale life models account for differing fatigue crack initiation based on the size scale of the defect and microstructure features, including provisions for generally millimeter scale casting flaws, generally micrometer scale second phase particles by cracking or debonding, or submicrometer scale dislocation interactions with precipitates which form persistent slip bands. In the presence of casting flaws, the fatigue initiation life is negligible and the total fatigue life is spent in propagation of a fatigue crack from such flaws. In the absence of casting flaws, however, the total fatigue life is spent in both crack initiation and propagation, except for the case where fatigue cracks initiate from large second phase particles in a coarse microstructure. The extreme values of casting flaws, second phase particles, mean free path through an aluminum matrix or grain sizes are obtained from extreme value statistics when two or three dimensional sizes of casting flaws and microstructure features are provided by either direct measurement or analytical prediction. The upper bound flaw or microstructure feature size is calculated by extreme value statistics.

The invention is directed to an improved semiconductor chip that reduces crack initiation and propagation into the active area of a semiconductor chip. A semiconductor wafer includes dicing channels that separate semiconductor chips and holes through a portion of a semiconductor chip, which are located at the intersection of the dicing channels. Once diced from the semiconductor wafer, semiconductor chips are created without ninety degree angle corners.

The invention relates to a continuous casting method of large-length hollow ductile cast iron sections and a method for arcing the hollow ductile cast iron sections after local continuous heating. Thesection comprises the following components by weight percent: 3.4-3.6% of C, 2.8-3.2% of Si, 0.40-0.60% of Mn, S less than or equal to 0.1%, P less than or equal to 0.1% and the balance Fe. Molten iron is subjected to shaping and continuous casting under multiple physical fields to become the hollow sections. The molten iron in heat preserving furnaces is separated from dross, sand and gas in twoways, thus completely solving the defects of dross inclusion, sand inclusion and pores; liquid column cores in a crystallizer carry out continual feeding on condensing tube shells, thus eliminating the possibility of shrinkage porosity inside the tube walls, obtaining highly dense cast structure of (ferritic matrix+spherical graphite) and eliminating crack initiation origins in thermoplastic deformation to be carried out later. The intense cooling speed in the crystallizer enables the volumes of eutectic cells to be only 1/15-1/25 of the volumes of traditional sand mould casts. The density ofthe graphite balls reaches around 500/mm<2>. In plastic deformation, the micro slip orientation is increased and the ductility is enhanced, therefore, the hollow cast iron sections can be arced by medium frequency induction heating and bending.

The invention relates to a testing method of steel fiber reinforced concrete fracture test crack initiation load, and belongs to the technical field of concrete cracking parameter testing. The testing method provided by the invention is characterized in that when a steel fiber reinforced concrete coped beam specimen cracks, a stress intensity factor of a prefabrication crack front edge achieves concrete fracture toughness, and the steel fibre blocking action is not exerted; the stress intensity factor generated by external load and concrete cracking toughness(i)K(/i) IC are equal, the external load value which is corresponding to a numerical value (i)K(/i)IC of the stress intensity factor generated by the external load can be used for determining the crack initiation load according to the curve relation graph of the external load and the stress intensity factor (i)K generated by the external load (img file='2014100081259100004dest_path_image002.TIF'wi='8'he='21'/)(/i)-(i)P(/i) curve relational graph. The testing method provided by the invenytion has the advantages that the required equipment, analyzing and processing method are simple, the cost is low, and the precision is high.

A method of cutting glass that prevents uncontrolled crack propagation when high background stress is present, either in the form of thermal residual stress, external mechanical stress or a combination thereof. The method includes masking an edge of the glass by blocking the beam using highly reflective or absorptive material located near the glass surface, or deposited on the surface in a form of a thin film (or highly reflective paint) to prevent uncontrolled crack initiation and propagation starting from the glass edge. The initiation of the laser scoring is located at a predetermined distance from the glass edge. Yet another aspect of the invention embodies stopping propagation of the vent at the exiting end of the score line.

The invention discloses a three-dimensional multilayered multi-well fracturing prop crack real-time monitoring experimental system and method. The experimental system comprises a core test specimen, acore clamping device, a fully-three-dimensional multilayered stress loading device, a fracturing pumping-in device, a crack expansion real-time monitoring device and a control device. The invention provides the three-dimensional multilayered multi-well fracturing prop crack real-time monitoring experimental system and method, under the conditions that three-directional stress is applied, and twohorizontal directions are layered stresses, the core specimen which includes a plurality of shafts simulates hydraulic fracturing and sand supporting, by crack initiation on fracturing cracks and real-time and quantitative monitoring and later interpretation on crack induction stress of an expansion process, crack initiation of three-dimensional multilayered multi-well fracturing prop cracks and quantified description of the expansion process are realized, and the laying state of a propping agent in the cracks can be obtained.

The invention relates to a method for determining the crack initiation strength of a rock under compressive conditions. The method includes the following steps: 1, processing a rock sample; 2, arranging the rock sample on the sample bench of a press; 3, axially loading the sample in a load control mode until the sample is destroyed; 4, calculating the volumetric strain of the sample; 5, determining the crack damage strength in a volumetric strain-axial stress curve; 6, connecting a zero point with the crack damage strength point in the volumetric strain-axial stress curve to form a reference line; 7, calculating a difference between the strain value in the volumetric strain-axial stress curve and a strain valve corresponding to the reference line under a same stress level from the zero point to the end of the crack damage strength; and 8, making a volumetric strain and axial stress relation point diagram, and determining the stress corresponding to the peak of the volumetric strain difference as the crack initiation strength of the rock. The method is suitable for mechanical test of the rock, serving for underground engineering.

The invention discloses a perforation fracturing permeability-improvement method for a high-stress low-porosity coal seam, and belongs to the field of disaster prevention and control of mining working faces of coal mines. The method comprises the steps that firstly, coal body mechanical properties are measured, and related technical parameters such as the perforation depth, coal body crack initiation pressure, the fracturing permeability-improvement radius, the separation distance between drilled holes and the separation distance between perforations are determined; then, a coal seam perforation system is installed, and perforation operation is conducted on the coal seam perforation system; after perforation operation is accomplished, a hydraulic fracturing system is installed, fracturing is started, water is injected, and changes of a pressure value are observed until fracturing operation is accomplished. According to the method, a fracturing structure is additionally arranged in a coal body, elastic potential energy of the coal body can be released effectively, and a preparation is made for rock burst prevention and control work of the working faces; meanwhile, high-pressure water can play a good role in moistening the coal seam, the quantity of dust produced during mining of the coal seam is reduced, creation of a good working environment is facilitated, and physical health of underground workers is protected.

The invention discloses a test method and a device for monitoring a steel wire fretting fatigue state. The device comprises a base, a support column, a top beam, a hydraulic lifting platform and a horizontal loading device. The test method comprises the following steps that two ends of a tested steel wire passing through the horizontal loading device are fixed respectively; the tested steel wire is stretched until the tested steel wire bears a preset initial load; the horizontal loading device is moved so that loading steel wires in the horizontal loading device compress tightly the tested steel wire; the hydraulic lifting platform is controlled to move up and down to apply alternate loads to the tested steel wire; the tested steel wire generates fretting fatigue; a tangential force is transmitted to a spoke-type pull-press sensor through an internal thread connecting rod arranged on a loading block, wherein an acoustic emission sensor is arranged on an upper grip block of the top beam; and the test is stopped when the tested steel wire is broken because of fretting fatigue. The device can dynamically record a tangential force between contact steel wires and tested steel wire acoustic emission signals in an experimental process, and provides an effective basis for research on a steel wire fretting zone, crack generation and fracture mechanisms of a fretting zone, and influences of the crack generation and the fracture mechanisms on a fretting fatigue life. The device has a simple structure, is convenient for operation and has good effects.