17 results about "Intensity factor" patented technology

The invention relates to a method for predicting and evaluating the multi-axial fatigue life of an additive manufacturing K418B nickel-based superalloy. Comprising the following steps: S1, carrying out intrinsic characteristic characterization on a material, including mechanical property test and defect statistical analysis based on industrial CT and a scanning electron microscope; s2, carrying out single-axis, multi-axis and notch fatigue tests of the system, and analyzing the association between the microstructure and the fatigue life; s3, based on a fracture mechanics theory, correcting the traditional model by taking the equivalent crack propagation driving force delta KDF as a special parameter, and constructing a multi-axial fatigue life prediction model; s4, determining a calculation method of an equivalent stress strength factor Keq optimized by adopting a weight coefficient through a multi-axial fatigue test, and establishing a notched part service life prediction model considering crack propagation driving force; and S5, performing fatigue test verification by designing and manufacturing a simulation piece, and verifying the accuracy and reliability of the multi-axial fatigue life prediction model. According to the method, the prediction precision and the engineering applicability of the fatigue life of the additive manufacturing K418B alloy under the high-temperature multi-axial load are remarkably improved.

The present application belongs to the technical field of wind power generation, and specifically relates to a wind power tower material crack propagation prediction method and system, which is suitable for fatigue life evaluation of large supporting structures in the wind energy industry. The method comprises: deploying a multi-source heterogeneous sensor network to collect strain, acoustic emission and environmental load data; constructing a digital twin high-fidelity finite element submodel to obtain a dynamic stress intensity factor; constructing a deep neural network, embedding the Paris law of fracture mechanics in the form of residual into the loss function to form a physical information neural network, and realizing crack propagation rate prediction; using the extended finite element method combined with the level set function and the maximum circumferential stress criterion to dynamically track the three-dimensional space expansion path of the crack; combining Monte Carlo simulation and recursive Bayesian update to evaluate the remaining life and trigger graded early warning. The present application solves the problems of insufficient fusion of physical mechanisms and data-driven in the prior art, low prediction accuracy under small samples, and lack of crack space path tracking.

This invention discloses a method for predicting crack propagation path and remaining life of a notched component with irregular cracks, comprising: designing a notched feature specimen of the notched component with irregular cracks based on the principle of local stress field consistency; establishing a three-dimensional model of the notched feature specimen in ABAQUS and establishing an interface connection between ABAQUS and the three-dimensional crack propagation simulation platform Franc3D to perform dynamic simulation of crack propagation and obtain opening, shear, and tearing stress intensity factors; calculating a composite equivalent stress intensity factor as a measure of crack propagation based on the opening, shear, and tearing stress intensity factors obtained from the simulation, and extracting the composite equivalent stress intensity factor at the leading edge point with the largest increment; estimating fatigue crack propagation life based on the composite equivalent stress intensity factor at the leading edge point with the largest increment; and fitting a crack propagation curve based on the stress-life curve and the fatigue crack propagation life expression. This invention effectively improves the prediction accuracy of crack leading edge trajectory and the accuracy of crack propagation life assessment.

The invention provides a method for determining the crack propagation rate of nickel-based alloy weld stress corrosion cracking, which comprises the following steps: S1, preparing a nickel-based alloy test plate with the same specification and welding process as an actual service component, and welding different areas on the nickel-based alloy test plate; s2, calculating an index n of a stress field intensity factor K; s3, calculating a CGR coefficient alpha and an index beta of HV or sigma s; s4, calculating activation energy Q; s5, a CGR model expression for unifying SCC of different areas of the nickel-based alloy weld joint is obtained; wherein CGR is the crack growth rate, HV is the Vickers hardness, and sigma s is the yield strength. The invention develops a new model for directly predicting the SCC CGR of each region of the welding seam according to the Vickers hardness (HV) or yield strength (sigma s) field test result of each region in combination with a stress field intensity factor (K). After the model is established, the CGR of the corresponding part can be obtained only by carrying out Vickers hardness or ball indentation test on different parts on site to obtain HV or sigma s, and data required by evaluation are more accurately and directly provided.

The disclosure provides a high-temperature fatigue life prediction method based on EIFS, and relates to the technical field of reliability design. The method comprises the following steps: acquiring first test data of crack propagation test and high-cycle fatigue test on a smooth member, and second test data of test on a notched member; determining equivalent initial defect sizes of the smooth member and the notched member according to the first test data and the second test data; obtaining an equivalent stress intensity factor difference and a fatigue crack propagation rate of the notched member under a high-temperature condition according to the second test data; fitting a function relationship among the fatigue crack propagation rate, the equivalent stress intensity factor difference and a crack size to obtain a crack propagation function; and determining a predicted fatigue life of the notched member under the high-temperature condition based on the crack propagation function, the equivalent initial defect size of the notched member and a limit crack size. The disclosure can realize accurate high-temperature fatigue life prediction.

The application discloses a method for improving the fracture plugging effect of drilling fluid by combining a three-pore medium flow model with dislocation fracture mechanics, and comprises the following steps: inputting a parameter set, constructing a three-pore medium flow model, configuring a solving mode, and solving and calculating to obtain the fluid pressure p in the fracture f , distributing simulation results, constructing an equation group by writing program codes, importing p f data, running the program, calculating a dislocation distribution function f(t k ), and further obtaining a fracture width W(t k ), a fracture tip stress intensity factor K I ; the fracture intensity factor K I under different conditions is obtained by modifying parameters, a K I vs. related parameter graph is drawn, a toughness coefficient K IC of a target formation is imported, for example, K IC >= K I , which indicates that the fracture will continue to expand; the fracture width and fracture re-expansion during the drilling process are predicted in real time, the plugging material is reasonably designed, the one-time plugging success rate of the fracture leakage is improved, and the continuous leakage and malignant leakage are avoided.

The application discloses a method for obtaining a critical stress intensity factor of a hydrogen environment material, and belongs to the technical field of stress intensity factor measurement. According to the method, a hollow notch sample is prepared according to hydrogen embrittlement research on a suitable pipeline material, then hydrogen is filled into two ends of the sample, a tensile test is loaded, and the test is stopped after the sample fails and breaks due to hydrogen embrittlement. The method is more in line with the stress state of an actual pipeline, can provide stress intensity factor values of the material under different loads and the critical fracture stress intensity factor of the material, and has important significance for evaluating the fracture toughness and crack resistance of the material in a hydrogen environment.

A parallel multi-scale calculation method for effectively calculating the fracture toughness of solid electrolytes (GDCs) is disclosed. The method involves: calculating a millimeter-scale model using ABAQUS; transforming the millimeter-scale model into a nanometer-scale model using an equivalent stress intensity factor; and performing multi-scale calculations on the core region of the nanometer-scale model, with boundary conditions provided by the ABAQUS calculation results. This invention enables the study of the uniaxial tensile fracture behavior of GDCs with a central crack at different temperatures. Based on fracture mechanics theory, the macroscopic structure of the GDC is transformed into a microscopic intermediate transition model using the equivalent stress intensity factor method, and a detailed calculation process for analyzing the fracture toughness of the macroscopic structure of the GDC is provided through a multi-scale method. Furthermore, this multi-scale method investigates the fracture toughness of the macroscopic structure of the GDC under a force-electrochemical coupled field.

This invention discloses a method for predicting the crack propagation fatigue life of key components in wind turbine drivetrains, belonging to the field of fatigue analysis and remaining life calculation of generator components. The invention includes: calculating the global stress field under six sets of orthogonal unit loads based on the finite element method; establishing a nonlinear mapping relationship between real-time load and stress correction coefficients using a neural network; rapidly calculating a high-precision stress field in real time through linear stress superposition and neural network correction coefficients; extracting characteristic stress components in vulnerable areas of key components to construct a combined equivalent stress intensity factor; establishing a crack propagation rate model based on an improved Paris formula; and calculating the crack propagation fatigue life using fixed-step numerical integration. This method can be used for defect evolution analysis and crack propagation fatigue life calculation of key components such as gearbox shafts and bearing housing connectors in wind turbine drivetrains.

The invention provides a flood prevention and drainage structure fracture failure prediction method and system based on data fusion, and the method comprises the steps: carrying out the multi-scale feature extraction of a standardized fusion data set, carrying out the dimension reduction and fusion of all extracted features, and obtaining a low-dimensional fusion feature vector; based on the low-dimensional fusion feature vector, a fracture failure prediction model is adopted to perform fracture failure prediction on the flood prevention and drainage structure, and a dynamic stress intensity factor prediction value and a fracture toughness time-varying prediction value of a preset key part of the flood prevention and drainage structure are obtained; and taking the ratio of the dynamic stress intensity factor prediction value to the fracture toughness time-varying prediction value as a fracture failure risk index, when the fracture failure risk index exceeds a preset threshold value, generating graded early warning information, and based on the change trend of the fracture failure risk index, positioning a potential fracture failure part and predicting the residual safety life. The intelligent level and reliability of safety management of the flood prevention and drainage structure are greatly improved.

The invention relates to the field of testing the strength characteristic of a solid material through mechanical stress, in particular to a composite loading device and a critical stress strength factor measuring method, the device adopts cooperation of a screw and a nut to achieve constant displacement loading and locking, constant displacement stress can be provided for metal, and the critical stress strength factor can be measured. The whole body can be immersed into a corrosive medium; according to the method, a load-displacement curve is calibrated, constant displacement is applied to a sample, a stress corrosion test is carried out, after crack propagation is stopped, the residual load and the crack length of the sample are measured, and finally a critical stress intensity factor is calculated. According to the embodiment of the invention, a powerful basis is provided for deeply researching the mechanical behavior and failure mechanism of the metal under the condition of constant displacement stress corrosion.

This application discloses a method, device, storage medium, and program product for safety performance assessment of cracked jacket structures, belonging to the field of offshore wind power structural health monitoring and safety assessment technology. By real-time acquisition of strain field data and environmental loads, and combining this with a digital twin model of the cracked jacket structure, a first real-time stress intensity factor is obtained. By comparing the first real-time stress intensity factor with the current effective stress intensity, the model parameters of the digital twin model of the cracked jacket structure are updated, overcoming the limitation of traditional static models that cannot dynamically reflect crack propagation and structural performance degradation. Therefore, continuous, real-time perception and accurate assessment of the safety status of cracked jacket structures are achieved, providing a basis for timely detection of risks associated with cracked jacket structures.

This invention belongs to the field of reservoir development technology, specifically providing a method for simulating fracture networks in deep coal and rock fracture systems, including the following steps: S1, calculating key rock mechanics parameters and geostress parameters of deep coal and rock based on well logging interpretation data; S2, calculating equivalent rock mechanics parameters and equivalent geostress parameters of deep coal and rock; S3, calculating the equivalent stress intensity factor at the fracture tip and the critical stress for fracture initiation; S4, based on the equivalent stress intensity factor at the fracture tip and the critical stress for fracture initiation, simulating the fracture morphology, length, and branch fracture density using a lightning simulation-based fracture propagation calculation method; this invention solves the problem of low accuracy in existing deep coal and rock hydraulic fracturing fracture propagation methods. The fracture morphology, length, and branch fracture density simulated by this invention are highly consistent with electromagnetic waves and data ranges, laying the foundation for subsequent research on the propagation morphology of hydraulic fractures in coal and rock formations.

The invention discloses a method for predicting crack propagation fatigue life of key parts of a transmission chain of a wind driven generator, and belongs to the field of fatigue analysis and residual life calculation of generator parts. The method comprises the steps of calculating a global stress field under six groups of orthogonal unit loads based on a finite element method, establishing a nonlinear mapping relation between real-time loads and stress correction coefficients by adopting a neural network, and rapidly calculating a high-precision stress field in real time through linear stress superposition and a neural network correction coefficient. Characteristic stress components are extracted in a vulnerable area of a key component to construct a combined equivalent stress intensity factor, a crack propagation rate model is established based on an improved Paris formula, and the crack propagation fatigue life is calculated by adopting fixed step size numerical integration. The method can be used for defect evolution analysis and crack propagation fatigue life calculation of key parts such as a shaft system of a transmission chain gear box of a wind generating set, a bearing seat connecting piece and the like.

The application discloses a rock dynamic fracture I-type stress intensity factor calculation method, system and device, relates to the rock dynamics technical field, and the method comprises the following steps: collecting an image sequence of a granite test piece with a straight cut groove in a Brazilian disc through a dynamic impact test on the granite test piece; performing semantic segmentation on the image by using a Mask2former model, identifying a crack region, and automatically positioning a crack tip position at each moment based on a segmentation result; processing the image sequence based on a DIC method to obtain displacement field data of a test piece surface; determining a displacement field sub-region participating in calculation in a Williams equation based on the crack tip position and the displacement field data; and iteratively solving the I-type dynamic stress intensity factor based on a least square method by adjusting the shape and size of the displacement field sub-region, so that the measurement accuracy and efficiency of the dynamic stress intensity factor are significantly improved.

The invention discloses a method and system for obtaining interface adhesion parameters between an ice layer and an icing substrate, the method comprises the following steps: collecting the apparent adhesion force of the ice layer and the icing substrate interface, establishing an adhesion simulation model between the ice layer and the icing substrate, carrying out statics analysis on the adhesion simulation model, and calculating the interface adhesion parameters through adhesion simulation calculation to obtain the interface adhesion parameters between the ice layer and the icing substrate. Interface stress distribution between the ice layer and the icing substrate is obtained; calculating and obtaining stress intensity factor distribution of each point of the interface according to the relationship between the stress intensity factors and the stress; performing polynomial fitting by using the stress intensity factor of each point of the interface to obtain a current critical stress intensity factor; calculating the interface fracture energy of the ice layer and the icing substrate according to the relationship between the critical stress intensity factor and the fracture energy; the method comprises the following steps: establishing a debonding simulation model between an ice layer and an icing substrate, carrying out simulation calculation of interface debonding by using the debonding simulation model, and carrying out inversion according to interface fracture energy and collected apparent adhesion to obtain interface peak strength.

This invention discloses a fatigue fracture prediction method and system applicable to complex structures. The method includes: dividing the working condition of the region to be predicted into multiple sub-processes to obtain a sub-process set; determining the crack size at the current sub-process iteration number using the equivalent stress intensity factor and crack increment number at the current sub-process iteration number; updating the sub-process set; and performing the next iteration calculation on the sub-process set until the sub-process set is empty. This invention divides the working condition of the entire region to be predicted into multiple sub-processes and performs update and iteration calculations, thereby achieving the prediction of the fracture situation of complex structural regions under the entire working condition, filling the gap in existing technologies that cannot predict the fracture situation of complex structural regions.