190 results about "Crack size" patented technology

The invention discloses a method for repairing asphalt pavement cracks, comprising the following steps: a. opening a trench: setting the trench size according to the crack size and opening the trench;b. cleaning the trench: cleaning disintegrating slags in the trench and dust at the periphery of the trench after finishing opening the trench; c. pouring a crack: pouring cold crack filling materialin the trench, and performing vibration operation on the cold crack filling material after crack pouring; d. filling materials: filling joint stones in the trench and performing vibration compactionoperation on the stones until the stones after vibration and compaction in the trench level with the pavement; and e. curing. By using the method in the invention, asphalt pavement cracks can be effectively repaired by cold-patch notching and vibration, the cracks and gaps at the periphery thereof can be completely closed, the materials in the trench can be integrated with the original asphalt pavement after repairing, thus having high strength, resisting water encroachment thoroughly, improving the service life of the asphalt pavement remarkably and saving investment on whole-life maintenancecosts of the asphalt pavement greatly.

The invention discloses a fatigue crack extension testing method, making a sweeping test in the fatigue test course and obtaining the variation condition of vibration response of the test system varies with test piece crack extension on the forced vibration condition; using a numeric method to make sweeping data fitting and obtaining variation curve of resonant frequency with number of circulating times; after the test piece is broken, according to actually observed crack size and shape, prefabricating crack of a CAD model and making finite model analysis and obtaining a curve of resonant angular frequency of the system against test piece size, using the curve and able to obtain dynamic extension rule of test piece crack and then obtaining its curve of variation rate; and finally combining with calculation of stress strength factor range Delta K, and able to obtain a curve of crack extension rate.

A method of fatigue life prediction including: calculating a critical crack size of an object of interest; identifying a first flaw in ultrasound data of the object of interest; determining that the first flaw interacts with a second flaw, the first flaw is to be merged with the second flaw, or the first flaw is isolated; calculating an initial crack size based on the determination; and calculating an increase in the initial crack size due to fatigue and creep to determine a number of load cycles until the initial crack size reaches the critical crack size.

The invention discloses a method for selecting a plugging agent most suitable for a low permeability crack rock core from plugging adjusting agents to be selected. The experimental method comprises the following steps that (1) low permeability crack rock core models are prepared, wherein cracks are manufactured with an artificial low permeability homogeneous columnar rock core and an artificial low permeability homogeneous square rock core as matrixes by referring to actual low permeability crack reservoirs, and a crack columnar rock core model and a crack square rock core model are manufactured; (2) the crack columnar rock core model or the crack square rock core model is taken as a physical model, the plugging performance of different plugging adjusting agents with the injection amount same as the crack size, and the breakthrough pressure gradient, the residual resistance factor and the plugging ratio of each plugging adjusting agent are worked out; firstly, the breakthrough pressure gradient of each plugging adjusting agent is compared with the minimum starting pressure gradient of the model, and the plugging agents with the breakthrough pressure gradients smaller than or equal to the minimum starting pressure gradient are removed; secondly, the plugging rate of the rest of the plugging adjusting agents are compared, and the plugging adjusting agent which larger the plugging rate is, larger the breakthrough pressure gradient is serves as the most adaptive plugging adjusting agent for the low permeability crack rock core.

Provided is a method for preparing a simulated stress corrosion crack with the controllable crack size and conductivity. The method comprises the steps that firstly, two stainless steel test blocks are machined, and a pit flaw with a certain size and shape is pre-buried in a to-be-welded face of one test block according to the size of a real stress corrosion crack; then the pre-buried pit is filled with a selected high temperature resisting material with proper conductivity according to the conductivity of the real crack, and the two test blocks are welded together through the solid phase welding technology to obtain a welded test piece; the part, above the pre-buried flaw area, of the welded test piece is cut out, the machined surface flaw test piece can be used for eddy current testing experiments, and the real stress corrosion crack is simulated. The simulated test piece prepared through the method can effectively replace a stress corrosion crack test piece complex in actual shape and hard to prepare, the advantages of being easy to operate and achieve, low in cost and controllable in crack size and conductivity are achieved, and the test piece can be widely applied to a detectability certification system of a stress corrosion crack quantitative eddy current testing method.

The invention discloses a method for prefabricating a cement-based sample crack, a prefabricated sample and a prefabricating system. A configuration net which can form a fracture through removing net wires so as to produce a weak area is manufactured, and is put in the prefabricated sample during a process of casting to form the prefabricated sample, so that when the prefabricated sample is loaded by a pressure testing machine, not only can a crack size and a crack position of the prefabricated sample be controlled through the configuration net, but also the advantage of enabling the formed crack to get close to a crack produced by real stress cracking of concrete is realized.

The invention relates to a method and a system for testing nuclear power station pipeline leakage rate. The method includes: generating corresponding media with a medium generator; measuring medium mass through a mass flowmeter; cooling media, which is mixed by a mixer and flowed out from a test section, with a condensing device, measuring the media with the mass flowmeter, comparing measured mass with input mass, and regarding the measuring result as creditable if measured mass equals to or is close to the input mass; otherwise, repeating the test; and cutting open the test section, detecting crack surface roughness and a runner, using the detecting value as input of a leakage rate program, and comparing difference between the result of the leakage rate program and the measuring result. Crack size is simulated to build relation of flow and defined size, leakage test under actual working conditions can be performed aiming at actual cracks, and leakage amount of different load and crake forms can be measured.

A method for determining when a ceramic component on a platform should be replaced. The method includes determining parameters for the ceramic component, the parameters include empirically determined a critical stress intensity factor, and a geometry factor for the ceramic component. The method also includes determining a relationship between platform operational parameters to the generation of stress at the surface of interest of the ceramic component, determining an initial crack size of a crack within the ceramic component at installation, tracking operational parameters of the platform throughout a course of usage of the ceramic component, calculating the corresponding stress at the crack location due to the tracked operational parameters, and calculating a numerical solution that illustrates a crack growth rate velocity and tracks a size of the crack over time. The ceramic component is replaced based on the crack growth rate velocity and the size of the crack.

The invention provides a device and a method for monitoring crack propagation life of a valve casing and a cylinder of a turbine. The method includes the specific steps of: flaw detection and determination of crack size of the valve casing and the cylinder of the turbine; computation of maximum main stress, a critical crack size, a crack propagation life, outer surface crack propagation life accumulation loss, an outer surface crack propagation residue life, inner surface crack propagation life accumulation loss, and an inner surface crack propagation residue life of parts where the crack is; controlling the crack propagation residue life of the turbine valve casing and cylinder; and printing an output result. The device has the advantages that online calculation and regular monitoring of the crack propagation residual life of the valve casing and the cylinder of the turbine are realized, if the crack propagation residual lives of the valve casing and the cylinder of the turbine are over short, scheduled heavy repair (A-level repair) is arranged in time so as to reasonably utilize the crack propagation residual lives of the valve casing and the cylinder of the turbine, and a technical effect of regularly monitoring the crack propagation residual lives of the valve casing and the cylinder of the turbine is achieved.

The invention discloses a critical sand plug fracturing method for improving crack complexity. The method includes the following steps: (1) formation evaluation before fracturing; (2) preferable selection of viscosity of pre-crack generation fracturing fluid; (3) application of different viscosity fracturing fluid to generate cracks of different sizes at different stages; (4) preferable selectionof dosage proportion and particle size of a proppant matching the different crack sizes; (5) design of a bench type slug sanding mode; (6) implementation of a critical sand plug fracturing process; and (7) other construction steps and a flowback and production process. The method realizes the effective promotion of net pressure and an induced stress field in the whole process of one-time sand fracturing, thereby reducing a horizontal stress difference of two directions of a formation at different positions of a main crack to make the opening of natural cracks or micro cracks filled with calcium easier. The main crack turns and then communicates and intersects with the natural cracks or the micro cracks, thereby maximizing the complexity of the whole crack system and further improving the crack reconstruction volume and single well production.

The invention discloses a method for detecting micro-cracks of a pipeline through a frequency multiplication modulation and time reversals of a nonlinear ultrasonic guided wave, and belongs to the field of nondestructive detection. The method comprises the following steps: 1) signal excitation: using two groups of emission ultrasonic transducers, wherein a first group of emission ultrasonic transducer excitating a single low-frequency, and a second group of emission ultrasonic transducer excitating a double high-frequency; 2) signal reception: the second group of emission transducer simultaneously receiving signals as a reception transducer; 3) nonlinear analysis: selecting a time reversal window function according to a sound field modulation side lobe frequency of omega1+omega2=3omega1; 4) signal time reversal: reversing intercepted time reversal signals, and sending the intercepted time reversal signals by the excitation signal transducers; and 5) energy focusing: focusing the signals at the micro-cracks. According to the method for detecting micro-cracks of the pipeline through the frequency multiplication modulation and time reversals of the nonlinear ultrasonic guided wave, the identification of micro-cracks is realized by utilizing the advantages that the propagation distance of the ultrasonic guided wave is long and the nonlinear ultrasound is highly sensitive to micro-cracks, meanwhile utilizing the characteristic of adaptive focusing of the time reversal algorithm; and the crack size is determined by utilizing a nonlinear ultrasonic parameter.