359 results about "Stress strength" patented technology

The invention discloses a method for measuring fracture toughness of pipeline steel by using a unilateral notched tensile test. The method is characterized by comprising the steps of preparing a unilateral notched tensile test sample; prefabricating a tensile sample crack by wire-electrode cutting and fatigue crack growth rate test method; calculating crack growth amount according to the tensile sample cracks; and acquiring J integration and stress intensity factor K for characterizing the fracture toughness of the pipeline steel by drawing a J-R curve for characterizing crack resistance of the crack growth. The method measures the fracture toughness of the pipeline steel by using tensile samples (SENT samples), overcomes the defects that the scope of measurement results of tensile samples (SENT samples) by a conventional technology is so small that the fracture toughness of the pipeline steel can not be evaluated; the crack toughness value of the tensile samples (SENT samples) can be more reasonable; waste of test for pipeline steel materials can be prevented; and the method has the advantages of high measurement accuracy.

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 provides a pair of intelligent gloves, method and system for calorie consumption and hand posture recognition. The pair of intelligent gloves comprises a processor module, a memory module, a communication module, an induction module, an early warning prompt module, a display module, a power module, a switch module and a cloud server. The memory module, the communication module, the induction module, the early warning prompt module, the display module, the power module, the switch module and the cloud server are respectively connected with the processor module. The induction module comprises a pressure sensor and an IMU. The pressure sensor and the IMU are respectively used for being responsible for sensing hand stress strength and IMU data in users' fitness process, collecting source data according to user strength training and sending the source data to the processor module. The processor module is responsible for preprocessing of the source data. According to the pair of intelligent gloves, in the strength training process, the detection accuracy rate of detected motions is high, the rate of false alarm is low, and alarm signals can be sent when the hand posture is deviated.

The invention discloses a method for measuring high-temperature creep crack growth threshold value of material. The method comprises the following steps of: for a specific material, according to the creep crack growth test requirement, processing at least 6 standard compact tension specimens, performing crack prefabrication for the well processed at least 6 specimens on a fatigue performance tester, wherein the prefabricated crack length is 0.5 times of the width of each specimen; wedging a wedge-shaped block into an initial notch of each specimen, placing the headmost end of the straight part of the wedge-shaped block at the position of a loading line, providing displacement for the loading line, forming a stress-strain field characterized by a stress strength factor at the tip of the specimen crack, and providing a driving force for the creep crack growth, wherein the specimens with different initial stress strength factors grow after certain time under creep effect in high-temperature environment, and in the same time interval, the crack growth lengths are different; drawing for the different stress strength factors and the corresponding crack growth rates, and solving the creep crack growth threshold value of the material through an extrapolation method. According to the method provided by the invention, multiple specimens can be tested for one time, and thus, the test cost is greatly reduced and the test time is greatly shortened.

In a wireless IC tag utilizing a wireless IC chip, the wireless IC tag having sufficient stress strength is manufactured economically. There is adopted a structure in which an upper electrode and a lower electrode are respectively formed on a front surface and a rear surface of a wireless IC chip, and the upper electrode is connected to a first conductor and a lower electrode is connected to a second conductor, and the first conductor and the second conductor are connected outside the wireless IC chip. Thereby, it is possible to fabricate the wireless IC tag economically and to ensure the stress strength.

The invention relates to a method for verifying strength of each leaf of end contact type few-leaf oblique main and auxiliary springs and belongs to the technical field of suspension leaf springs. It is possible to verify and calculate stress strength of each of main and auxiliary leaves according to structural parameters, elastic model and allowable stress of all main and auxiliary leaves of the end contact type few-leaf oblique variable-section main and auxiliary springs, acting load of each auxiliary spring and maximum load bearable by a main spring. Experiments and simulation tests show that this method is correct, maximum stress verification calculations of all main and auxiliary leaves are accurate and reliable, the design level, product quality and life of the end contact type few-leaf oblique variable-section main and auxiliary leaf springs as well as vehicle driving smoothness may be improved; meanwhile, it is also possible to reduce designing and testing cost and increase product development speed.

The invention provides a method for testing the fracture toughness of rattan canes based on a three-point bending mode. The method comprises the following steps: preparing a sample, and regulating a water content rate so as to obtain a sample of which the water content rate is 10-12%; recording a load-crack opening displacement (PV) curve, measuring actual crack depths, and calculating critical loads PQ and critical stress intensity factors KQ. According to the method provided by the invention, the crack opening displacement is measured by a C.O.D Gauge, and the test precision is improved. Aiming at the characteristics of the rattan materials, the sampling method for testing the fracture toughness of rattan canes is ensured, and the measured results having high accuracy and good reproducibility are obtained. The calculation method for testing the fracture toughness of rattan cane, provided by the invention, provides qualitative and quantitative bases for the utilization of the rattan canes.

The invention relates to an aeroengine case seam allowance size repairing method. The porosity and hardness of a coating and the content of oxides in the coating can be effectively adjusted by controlling the plasma spraying power and the heating process of spraying powder during flying, and heat stress of the coating is reduced. The hardness and thermal expansion coefficient of the prepared nickel-aluminum coating are equivalent with those of a case, the bonding strength of the coating is far higher than the stress strength of a case seam allowance under the given working condition, and the use working condition of the aeroengine case can be met.

The invention discloses a method for measuring the oil well pipe corrosion cracking critical stress intensity and sensitive factor. It adopts U-type loading hook to do static loading-unloading closed loop movement to the pin-and-hole of the twin cantilever (DCB) sample before and after the sulfide stress corrosion cracking test, makes the firmer chisel, loads the DCB perpetuity shift sample and obtains the loading and the relate curve of the shift at the same time; it quantity measures the DCB sample firmer chisel initial level loading, firmer chisel loading DCB actual cantilever shift and the critical level loading value after the test.

The invention discloses a quantitative risk analysis method of pressure bearing equipment containing surface crack defects. The method comprises the following steps of: 1) carrying out non-destructive inspection on pressure bearing equipment to be analyzed; 2) calculating a stress strength factor KI of the pressure bearing equipment containing surface crack defects; 3) calculating plastic fracture degree Lr of the pressure bearing equipment; 4) calculating fracture failure degree Kr' of the pressure bearing equipment; 5) establishing a failure equation, substituting the Lr value and Kr' value into the equation, and carrying out calculation according to a formula Z=Kr'-(1-0.14Lr2)(0.3+0.7exp(-0.65Lr6); 6) calculating failure probability including surface cracks by using a Monte-Carlo method; and 7) determining a correction factor FD including surface crack defects and calculating failure probability of the pressure bearing equipment. According to the invention, the influences of the surface crack defects on the pressure bearing equipment are taken into consideration, the accuracy of risk analysis result is improved and the the pressure bearing equipment is inspected and maintained in a more target and more reasonable way.

The invention discloses a connection device for an LED lamp and radiating fins, which comprises a central tube and a plurality of the radiating fins, wherein the central tube takes the central tube as a center; the upper part of the central tube is connected with an annular lamp holder, while the lower end is connected with a lower shell; the plurality of the radiating fins are connected to the surfaces of the lamp holder, the central tube and lower circular pieces of the central tube; the fin body of each radiating fin is at least punched with more than one convex body; each convex body is pressed against one surface of the adjacent radiating fin; and the adjacent radiating fins contact by means of support of the convex body to enhance the stability, the stress strength and the thermal conductivity of all radiating fins and ensure that the adjacent radiating fins keep constant space.

The invention discloses a triaxial stress strength designing method for a vertical well casing string. The triaxial stress strength designing method for the vertical well casing string comprises the following steps of: determining the steel grade, the wall thickness and the setting lengths of a first-section casing; performing internal pressure strength check and tensile strength check on the top of the first-section casing; calculating the setting lengths Lon and Lan of the first-section casing; and performing internal strength and extrusion strength check on the first-section casing till the designed well depth is met. By simultaneously considering the influence of coactions of an axial force, an external extrusion force and an internal pressure on the strength of the casing, the magnitude of the triaxial stress is calculated, an equivalent stress is calculated and supposed to be equal to the yield strength of the casing, and the strength of the casing is designed, so that the design is more reasonable and the designed vertical well casing string is more durable.

The invention discloses a simulation method of single propagation expansion based on a quasi-continuous geomechanical model, which comprises the following steps: acquiring geological parameters, including three-dimensional geological information and rock physical property information; Correcting petrophysical information; Establishing three-dimensional geological model of stratum; establishing FEMfluid-solid coupling model; obtaining the pressure field, displacement field, stress field and strain field of the three-dimensional geological model by solving the fluid-solid coupling equations ofthe finite element method; judging whether cracks are produced or not according to the stress strength criterion; obtaining The fracture width, permeability matrix and flexibility matrix, and then calculating the influence of fracture on pressure field and displacement field. The simulation of single fracture propagation based on quasi-continuous geomechanical model is realized. The invention hasthe advantages of quick solution, high accuracy and good reliability, and effectively solves the problem of dynamic display of fractures in the process of hydraulic fracturing simulation.

The invention relates to a stiffened wallboard damage tolerance analysis method based on finite element analysis solving, comprising the steps of first, determining a crack growth direction according to aircraft wallboard structural form and load-bearing condition; setting limit crack length to determine model scale; second, establishing a crack-free stiffened wallboard details finite element model; third, applying total load to the model to solve wallboard stress distribution; fourth, simulating cracks different in length in the finite element model, and extracting note balance force and displacement of a crack tip unit; fifth, solving stress strength factor K for tips with different crack lengths of a stiffened wallboard in fourth step by applying virtual crack closure technique VCCT; sixth, subjecting the stiffened wallboard to crack growth life and structural residual strength analysis. The method can provide real simulation for stiffened wallboard different-size cracks, crack tip stress and strain condition, stiffened wallboard different-size crack stiffener stress level, and fastener load; crack growth analysis is performed on stiffened wallboard skin based on analysis results.

According to the service bridge sling fatigue life probability assessment method disclosed by the invention, fatigue test data are fitted by implementing fatigue crack propagation tests of a bridge sling high-strength steel wire under different stress ratios, and a relational expression of fatigue crack growth analysis model parameters and stress ratios is obtained; a stress concentration effect caused by a corrosion pit is fused into the stress strength factor model, and a sling high-strength steel wire fatigue crack propagation analysis model is established by adopting small crack growth andnear-threshold crack growth analysis; an initial crack is obtained on the basis of an equivalent initial crack principle, the fatigue life of a single steel wire is obtained by integrating a steel wire crack propagation model, a correlation coefficient is introduced, the influence of stress redistribution of a sling after wire breakage is considered, and life evaluation of the bridge sling underthe corresponding wire breakage rate condition can be achieved. The prediction method is reasonable and high in generalization performance, and can be used for predicting the fatigue life of the long-span bridge sling.

The invention belongs to the field of 3D printing and relates to a three-dimensional (3D) printing method based on three-dimensional braiding. The method is a TDBP three-dimensional braiding printing method capable of effectively fusing a three-dimensional braiding method and a three-dimensional printing method in the textile industry. According to the TDBP three-dimensional braiding printing method, the stress strength of a 3D printed product can be improved. According to the 3D printing method, the problem that a molded product is insufficient in stress strength in the three-dimensional printing industry can be solved, the application defects of the 3D printed product in a main bearing structural member and high functional parts are overcome, and the application field of the 3D printed product is widened.

The invention relates to a method for preparing a solid core rod of a one-step molded high-voltage composite insulator. At present, a large-diameter epoxy glass fiber core rod in particular a large-diameter solid core rod which is used for a high-voltage strut composite insulator and has the diameter of more than 130 millimeters does not exist domestically. The method for preparing the solid core rod comprises the following steps of: selecting an internal mold high pressure foaming system to make an uninterrupted closed cell foamed insulation core body; adopting the combination of a circumferential yarn and a longitudinal yarn to ensure that the circumferential yarn, the longitudinal yarn and the closed cell foamed core body enter a pre-forming mold at the same time; according to different stress strength grades, enwinding the yarn circumferentially for 1 to 3 layers; adopting a vacuum gum injecting method in a gum dipping process; adding the pre-forming mold and a gum injecting hole to a mold part; and putting the closed cell foamed core body, the longitudinal yarn and the circumferential yarn into the mold at the same time to soak an epoxy resin adhesive for solidification molding so as to ensure that the closed cell foamed core body is adhered to a fiber resin layer more firmly. A product produced by the preparation method can replace the large-diameter solid core rod and meet the operating requirements on the core body of the composite insulator.

The invention discloses a quick evaluation method for ultimate stress strength of an integrated circuit for spaceflight. The quick evaluation method includes temperature stepping stress test, quick temperature change stress test, vibration stepping stress test, and temperature and vibration comprehensive stress test. The whole process of each test tests the functions of a sample to be evaluated and records fault phenomenons. The other special stress can be exerted to the sample to be evaluated when exerting temperature or vibration stress, such as electric stress. According to the quick evaluation method for the ultimate stress strength of the integrated circuit for the spaceflight, through exerting a series of combined tests, the failure time of the product is reduced, and the evaluation test finishing time is reduced to one week from the original six months to one year; through the heat, power and electric stress combined test, a superimposed or coordination effect is formed, and the evaluation test completeness and precision are greatly improved. Multiple verification results prove that the product fault mode coverage rate discovered in the test evaluation can arrive at more than 98%.

The invention relates to an improved assembled constructional reinforced concrete structural member which is characterized in that the connecting end of the concrete structural member extends to form a concrete structure or connecting reinforcement; and the head of the concrete structural member is a cylindrical bolt head and/or a cylindrical thread head which is thickened in the radial direction and has the peripheral thickness of more than or equal to 4mm; the inner side of a bolt head at the cylindrical bolt head end is preliminarily sleeved with a connecting sleeve, of which the outer end is an internal thread and the inner end is a neck. During structural member assembly and reinforcement connection, only the connecting sleeve is needed to be moved outwards along the axial direction and rotated to be screwed together with the cylindrical thread head connected to the other end of the connecting sleeve, so that sleeve connection can be used for locating the reinforcement connection of the assembled concrete structural member, stress strength is achieved after the connection is finished, the construction speed for assembling and connecting the concrete structural member is greatly increased, the strength of a joint is greater than that of reinforcement base metal, the joint is stable in reliability and is not influenced by personal factors, only one connecting sleeve is needed, and therefore, smaller length of only 60-100mm is needed, materials are saved, the connection cost is low, and the defects of large construction workload for assembling an assembled reinforced concrete building in situ, labor waste for in-situ assembly construction, low speed and instable quality are overcome.

The invention relates to a magnetic-structural-coupling-field-based transformer winding deformation analysis method. According to the technical scheme, the method comprises the following steps: a transformer magnetic-structural coupling model containing an electromagnetic field model and a structural field model is established and attributes and constraint conditions of the electromagnetic field model and the structural field model are set; a current is loaded on the electromagnetic field model to obtain an analysis result of an electromagnetic field Lorentz force; the analysis result of the electromagnetic field Lorentz force is extracted and is loaded on the structural model as an electromagnetic field load, and deformation of the transformer winding and the stress strength are observed, thereby realizing the analysis of the transformer deformation. According to the invention, a magnetic-structural-coupling finite element analysis method is applied to the transformer winding deformation analysis and thus the analysis on the transformer winding deformation state is realized under the circumstances that no power failure occurs and no cover suspending needs to be carried out, so that work of field testing and cover suspension examination and the like can be avoided. On the premise that the analysis accuracy is guaranteed, the work load is reduced and the operation and maintenance costs are saved.

The invention discloses a testing method for the dynamic crack arrest toughness of an I-type crack under the impact load, and belongs to the technical field of geotechnical engineering. The method includes the steps of conducting impact test research through a large-diameter separated type Hopkinson pressing rod and a test configuration designed by an inventor, determining the dynamic crack toughness of a sample through an experiment-numerical value method, calculating the load borne by the sample and the moment of crack arrest through strain signals obtained through a test, inputting an obtained time travel curve to a finite element program Ansys, calculating the near-field displacement of a crack tip through a 1/4 node unit, obtaining the time travel curve of the I-type dynamic rupture stress strength factor of the sample through a displacement extrapolation method, obtaining the strain strength factor value corresponding to the crack arrest moment as the dynamic crack arrest toughness of the material, and then obtaining the pure I-type crack dynamic crack arrest toughness under the effect of the impact load. The method is simple and convenient to operate and should have more practical application meaning in research of the dynamic crack arrest characteristic of rock under the impact dynamic load.

The invention relates to a fatigue crack expansion testing technology, and specifically relates to a bidirectional fatigue crack expansion rate testing method and testing system. The testing method comprises the following steps: prefabricating a semicircular gap in the center of a test piece; clamping the test piece in a fatigue testing machine; applying an alternating load to prefabricate fatigue cracks; adopting a constant equivalent amplitude circulating load to carry out a fatigue crack expansion experiment, during the experiment, applying a labeling load so as to leave a label line for reading, reading the fracture under a tool microscope to obtain the semi-length (a) of the label line along the width direction of the test piece, the depth (c) of the label line along the thickness direction of the test piece, and corresponding circulation number (N) of the alternating load; calculating the stress strength factors of the surface cracks under the clamping boundary conditions; according to a, c, and N, evaluating the crack expansion rate so as to determine the bidirectional fatigue crack expansion rate parameters: nA, CA, nB, and CB. The method can directly read the crack forms and sizes from the fracture, the result is precise, no extra facility is needed, and one experiment can obtain the fatigue crack expansion rate parameters in two directions.