80 results about "Damage tolerance" patented technology

The invention provides a wheeltrack damage monitoring method based on damage tolerance design and digital twinborn driving, and belongs to the technical field of wheeltrack damage monitoring, and the method comprises the steps: 1) constructing a wheeltrack system digital twinborn body module; 2) establishing a wheel track damage tolerance database; the method comprises the steps of (1) data feedback, (2) data feedback, (3) deployment of a multi-source sensing system, (4) damage state real-time mapping, (5) damage limit intelligent judgment, (6) a machine learning optimization module and (7) generation of a grading early warning instruction.The method can solve the problem that evaluation indexes fed back by existing twin data driven damage monitoring model data and existing damage tolerance design cannot be applied to the service process of a wheel-rail system in real time.

The invention discloses a method and device for predicting the fatigue life of a high-temperature alloy vacuum electron beam welding structure, and belongs to the technical field of aero-engines. The method comprises the following steps: acquiring fatigue experiment data of a target high-temperature alloy standard sample; extracting the maximum area of an initial defect, a defect shape factor and crack source position information; obtaining a stress intensity factor range considering defect morphological characteristics and a fatigue crack propagation threshold value of a material structure containing initial defects, and correcting a damage tolerance theoretical formula to obtain simulation data; fatigue test data and simulation data are fused to form an initial data set, a fatigue limit is calculated and expanded to the data set, the expanded data set serves as input, training is conducted through a support vector regression method, hyper-parameters are determined through Bayesian optimization, and a fatigue life prediction result of the high-temperature alloy vacuum electron beam welding structure is output. The method provided by the invention can well consider the influence of different morphology defects on the fatigue performance of the welded joint.

The invention relates to the field of test methods, in particular to a method for estimating the fatigue crack growth rate of a corrosion-resistant metal composite material, which comprises the following specific steps: S1, preparing a sample, and measuring and recording the thickness B, the width W and the machining notch length am of the sample; s2, prefabricating fatigue cracks; s3, selecting test parameters; s4, carrying out a fatigue crack growth rate test; s5, calculating the opening displacement variation (delta delta) of the crack tip; s6, forming a data group, analyzing a distribution rule and establishing a mathematical model; and S7, carrying out damage tolerance design and fatigue life check. According to the method, the crack tip opening displacement variation delta delta is used as a driving parameter to describe the fatigue crack propagation rule of the corrosion-resistant low-strength high-plasticity metal material and the composite material of the high-strength low-plasticity metal material; the method can solve the crack propagation problem that K is only suitable for elastic or small-range yield and r cannot be fully covered under the condition of plastic yield.

The invention discloses a design method of a periodically-arranged porous thin-wall combustion chamber flame tube characteristic simulation piece, which comprises the following steps: carrying out fluid-thermal-solid coupling analysis in a real structure service environment, obtaining the temperature field distribution of a combustion chamber flame tube and the size and direction of a first principal stress, and determining a part with the maximum first principal stress as a dangerous part; inserting an initial crack into a dangerous part of a real component, carrying out crack propagation numerical simulation, and extracting a stress intensity factor change rule on a crack propagation path; on the basis of keeping key geometric characteristics of a periodically arranged porous structure, a simulation piece is configured and designed into a biaxial flat plate stretching piece, and stress gradient distribution of a real component is matched through porous array parameter optimization; a biaxial tensile testing machine is adopted to apply a multi-axial load to the simulation part, and it is ensured that the stress intensity factor amplitude under different crack lengths is kept consistent with that of a real component. The method has important engineering value for damage tolerance evaluation and life prediction of the aero-engine combustion chamber.

The invention belongs to the technical field of material mechanical property testing, and discloses a metal material thermal mechanical fatigue crack propagation testing method which comprises the following steps: firstly, obtaining a function relationship between crack length and sample flexibility and a function relationship between crack propagation driving force and crack length through a finite element method; then prefabricating cracks by using a dead load method under a normal temperature condition, and carrying out a thermal mechanical fatigue crack propagation test to obtain a test result; and finally, the crack length corresponding to each cycle of the metal sample is calculated through an improved flexibility method, and the crack propagation rate is calculated by combining the function relation between the crack propagation driving force and the crack length. According to the method, the working conditions of variable temperature and alternating load coupling borne by the high-temperature component in the service process can be effectively simulated, the specific crack propagation rate and the plastic zone evolution condition of the crack propagation area are obtained, and important test data and theoretical basis are provided for damage tolerance design and safety check of the high-temperature structure under the severe working conditions.

The invention discloses a damage tolerance evaluation method and system for a friction plug repair welding joint of a carrier rocket storage tank, and the method comprises the steps: detecting an interface of the friction plug repair welding joint of the carrier rocket storage tank, and obtaining defect information, constitutive parameters of a material, and material attributes; establishing a finite element model, and accurately setting corresponding distribution interface defects; quantizing in-plane and out-plane restraint effects of the crack tip by adopting restraint parameters; processing and preparing a unilateral notch tensile sample, and measuring a local J-R curve of the tip of the precrack at the interface of the friction plug repair welding joint; correcting a real J-R curve of the friction plug repair welding joint of the rocket tank based on the influence of the distribution interface defect characteristics; then the tensile strength values of the friction plug repair welding joint in all the positions in the circumferential direction are corrected, and a corrected real J-R curve is obtained; and the limit crack size under the action of the corresponding internal pressure is obtained by utilizing the crack tip extension driving force curve, and then the critical J integral of the crack is calculated, so that the maximum crack size under the specific load or the maximum internal pressure under the crack with the specific size is obtained.

The invention relates to the field of aircrafts, and discloses a sandwich-structured composite material mute paddle, which comprises a paddle blade, and the paddle blade is a sandwich carbon fiber laminated structure composed of an upper layer prepreg laying layer unit, a foam sandwich layer and a lower layer prepreg laying layer unit; the upper-layer prepreg laying unit and the lower-layer prepreg laying unit are each of a bionic spiral structure formed by stacking multiple layers of composite material prepreg sheets in a bionic spiral laying sequence. The invention further discloses the preparation method of the composite material mute paddle of the sandwich structure. Load can be effectively transmitted and dispersed along fiber paths in different directions in the outer-layer prepreg bionic spiral structure, so that the comprehensive rigidity, the torsional property and the damage tolerance of the paddle are improved, the material characteristics are optimized, a three-section type pressurization method is adopted, a stable external pressure environment is established in the early stage of paddle foaming, and the mechanical performance of the paddle is improved. And dynamic balance and collaborative forming of internal and external pressure in the paddle forming process are achieved.

A method of analyzing a composite structure for damage tolerance. The method includes obtaining a structural configuration and determining at least one metric of interest for the structural configuration. A dent depth meta-model is developed based on the structural configuration, the at least one metric of interest, and information obtained from a machine learning algorithm. The at least one metric of interest provides a constraint for the dent depth meta-model and the machine learning algorithm is trained based on a historical physical test dataset of a plurality of composite components. The dent depth meta-model is utilized to estimate an impact energy to establish a threshold dent depth in the structural configuration. A computer-based simulation is performed with the structural configuration utilizing the impact energy from the dent depth meta-model. At least one design value is determined for the structural configuration based on output data generated from the computer-based simulation.

The invention discloses a thermal mechanical fatigue crack growth rate testing method based on rigidity and a crack tip strain field. The method comprises the following steps: firstly, establishing a relation function between normalized crack length and normalized rigidity through finite element calculation; secondly, performing DIC speckle preparation for observing crack propagation and analyzing a strain field; then carrying out a thermal mechanical fatigue test, calculating the crack length based on a rigidity change result of the test, drawing an a-N relation curve in combination with a DIC synchronous observation result, and carrying out comparative analysis; and finally, calculating the crack growth rate through a three-point moving average secant method, and analyzing and determining the size of a crack tip plastic zone according to a DIC strain field, so as to accurately test the crack growth rate. The fatigue crack growth behavior under the thermal-mechanical coupling effect can be effectively tested, the thermal mechanical fatigue crack growth rate is accurately obtained by combining a crack tip strain field measurement method, and test data support is provided for damage tolerance design and structural integrity evaluation of high-temperature pressure-bearing equipment.

The invention discloses a residual life prediction method applied to a hot end component of an aero-engine, which comprises the following steps of: performing finite element analysis on the hot end component of the aero-engine with cracks, and determining J integral and stress three-axis degree of a crack front edge node under different loads; the representative position of the crack front edge is determined by combining the J integral of the crack front edge and the stress three-axis degree processing result; generating a traditional failure assessment diagram through the J integral of the representative position of the crack front edge; a correlation function of crack driving force and ligament yield parameters under different crack sizes is constructed, and a failure assessment diagram and a damage tolerance failure assessment diagram combined with the crack size effect are generated; and performing allowable crack size and residual fatigue life prediction to obtain a fatigue life prediction result. According to the method, the residual life prediction precision and reliability of the aero-engine hot end component are improved, the service cycle and maintenance strategy of equipment are optimized, and potential safety hazards caused by structural failure are reduced.

The invention belongs to the field of fatigue strength test design, and relates to a helicopter tail section damage tolerance test load spectrum simplification method. The method comprises the following steps: taking a task section of a single test load spectrum block as a unit, and obtaining a simplified spectrum based on a rain flow counting method; attaching a landing state to each mission profile, and calculating the total cycle index of the individual mission profile after the landing state is considered according to the time proportion of the individual mission profile in the test load spectrum and the total number of times of the landing state; meanwhile, the landing state is classified into various landing working conditions in a refined mode, and the corresponding frequency of each landing working condition in the load spectrum block is calculated; determining a specific landing condition corresponding to a single mission profile, and recording the total number mj of the jth flight state of the test spectrum block; j is any integer from 1 to the total number of flight states; simplifying and combining task profiles of the test load spectrum block with the additional landing state; and carrying out load balancing on the test load spectrum block in each flight state and each landing state, and determining a loading load.

The invention relates to a nuclear power plant main pipeline damage tolerance establishment method. The method comprises the following steps: S1, determining the critical crack size of the main pipeline of the nuclear power plant at the end of the life; and S2, performing finite element calculation based on the established finite element model of the crack-free structure of the main pipeline so as to obtain stress distribution of the crack-free structure under each load working condition. S3, according to the initial crack size and the finite element calculation result, stress intensity factor calculation, transient pairing, elastic-plastic correction and fatigue crack propagation calculation are conducted in sequence, and the life end crack size of the main pipeline is obtained. And S4, when it is judged that the life end crack size of the main pipeline is smaller than the critical crack size, the step S3 is executed again to conduct iterative calculation on the initial crack size. And when the final crack size of the service life of the main pipeline is judged to be greater than the critical crack size, taking the initial crack size updated by the last iteration as the structural damage tolerance. The nuclear power pipeline defect evaluation period can be shortened, and the evaluation efficiency is improved.

The invention provides a rock mass blasting parameter inversion method, electronic equipment and a storage medium, and belongs to the technical field of blasting parameter design. The method comprises the steps that the damage tolerance and first blasting parameters of a rock mass are determined; the explosion process of the explosive is divided into a first stage dominated by stress waves and a second stage dominated by detonation gas. In the first stage, damage factors of the rock mass under stress wave damage are calculated. In the second stage, based on the damage factors, the crack expansion degree of the rock mass under the explosion gas damage is calculated, the damage prediction radius of the rock mass is obtained, and a damage prediction model is constructed. And calculating a first damage radius of the rock mass under the first blasting parameter based on the damage prediction model. When the first damage radius is smaller than or equal to the damage tolerance, the first blasting parameter is output, otherwise, the first blasting parameter is adjusted to be a second blasting parameter, and when the second damage radius is smaller than or equal to the damage tolerance, the second blasting parameter is output. The inversion method provided by the invention can improve the precision degree of controlling the blasting damage range.

To meet the requirement of the demonstration of durability and damage tolerance (DaDT).SOLUTION: The method includes obtaining a structural configuration and determining at least one metric of interest for the structural configuration. A dent depth meta-model is developed based on the structural configuration, the at least one metric of interest, and information obtained from a machine learning algorithm. The invention provides a constraint for the dent depth meta-model, and the machine learning algorithm is trained based on a historical physical test dataset of a plurality of composite components. The dent depth meta-model is utilized to estimate an impact energy to establish a threshold dent depth in the structural configuration. A computer-based simulation is performed with the structural configuration utilizing the impact energy from the dent depth meta-model. At least one design value is determined for the structural configuration based on output data generated from the computer-based simulation.SELECTED DRAWING: None

The application discloses a kind of laminated composite intercalation repair methods, belong to laminated composite maintenance technical field.The application uses the way of multilayer intercalation reinforcement patch, significantly increase the bonding area of patch and original laminated laminated composite material, can effectively improve the bonding strength of repair area, so that repair area will not become laminated laminated composite material / member dangerous area;The bonding surface is composed of multiple planes, and adjacent bonding surfaces bear tensile or shear load respectively, and after debonding or damage of a certain bonding surface, the crack will not spread to other bonding surfaces, significantly enhance the damage tolerance of repair bonding area, and further improve the mechanical properties of repair material / member.

The invention discloses a die forging forming method for a high-strength, high-toughness and damage-tolerance type titanium alloy cylindrical part. The die forging forming method comprises the following steps of S1, raw material heating, S2, primary forging, S3, surface treatment, S4, secondary forging and S5, annealing. By means of the method, the raw material weight and the forging heating number can be reduced, the production cost is reduced, and meanwhile it can be guaranteed that all properties of the product are good, and the product quality stability is improved.

The present invention belongs to the technical field of material mechanical property testing, and discloses a method for testing the thermomechanical fatigue crack propagation of metal materials. First, the functional relationship between the crack length and the flexibility of the sample, as well as the functional relationship between the crack propagation driving force and the crack length are obtained by the finite element method; then, a crack is prefabricated using the constant load method under normal temperature conditions, and a thermomechanical fatigue crack propagation test is performed to obtain the test results; finally, the crack length corresponding to each cycle of the metal sample is calculated by the improved flexibility method, and the crack propagation rate is calculated in combination with the functional relationship between the crack propagation driving force and the crack length. The present invention can effectively simulate the working conditions of variable temperature and alternating load coupling that high-temperature components are subjected to during service, obtain the specific crack propagation rate and the evolution of the plastic zone in the crack propagation area, and provide important experimental data and theoretical basis for the damage tolerance design and safety verification of high-temperature structures under severe working conditions.

The application discloses a kind of wind power main shaft and the manufacturing method for improving its fatigue resistance, belong to wind power equipment key component manufacturing technical field.The method includes the following steps: multi-direction upsetting and drawing forging is carried out to medium carbon alloy steel ingot, and blank is obtained;The blank is cryogenically pretreated, and then heated to room temperature;Then, composite quenching and tempering heat treatment, surface composite strengthening treatment and low-temperature aging treatment are carried out in sequence.The above-mentioned method is easy to operate, can effectively improve the fatigue life of wind power main shaft, compared with the fatigue life of wind power main shaft manufactured by traditional process can be improved by 50%-100%, and the damage tolerance and safety reliability of wind power main shaft under severe working conditions can also be greatly improved.

The application belongs to the technical field of aero-engine composite material fan blade damage tolerance performance evaluation, and specifically discloses a composite material high-speed soft body impact damage pre-preparation test device and a test method, which comprises an air compressor, an air chamber, an air gun support table, a composite material high-speed soft body impact damage pre-preparation test table, a soft bullet launching system and a multi-view camera monitoring system; the air chamber is connected with the air compressor and the soft bullet launching system at two ends respectively, the soft bullet launching system is located on the air gun support table, the air gun support table is connected with the composite material high-speed soft body impact damage pre-preparation test table, and the multi-view camera monitoring system is arranged around the composite material high-speed soft body impact damage pre-preparation test table. The application solves the problems that the existing technology may cause damage in the clamping area, affect the reliability of the test result of the residual tensile bearing capacity after impact, and lack the controllable problem of the high-speed soft body impact damage area.

The invention discloses a multi-axis random load fatigue crack propagation life analysis method. The method comprises the following steps: converting a multi-axis random load at a structure loading position into an equivalent random load at a dangerous point; establishing association between the random load at the dangerous point and the damage parameter on the crack propagation plane, and determining the most dangerous load combination through a multi-axis load projection theory; utilizing a rain flow counting method which introduces a processing strategy of rearranging according to a cycle starting time sequence to obtain cycle information and load sequence information of a random load spectrum; and based on a rain flow counting result, performing crack propagation life analysis by combining an NASGRO model and a cycle jump method, and calculating the total crack propagation life by using a Miner damage accumulation criterion. According to the method, the influence of the phase difference and stress ratio on the crack propagation life before the multi-axis random load is considered, the accuracy of crack propagation life prediction under the multi-axis random load is improved, and a basis is provided for damage tolerance design analysis of engineering components.

A method of analyzing a composite structure for damage tolerance. The method includes obtaining a structural configuration and determining at least one metric of interest for the structural configuration. A dent depth meta-model is developed based on the structural configuration, the at least one metric of interest, and information obtained from a machine learning algorithm. The at least one metric of interest provides a constraint for the dent depth meta-model and the machine learning algorithm is trained based on a historical physical test dataset of a plurality of composite components. The dent depth meta-model is utilized to estimate an impact energy to establish a threshold dent depth in the structural configuration. A computer-based simulation is performed with the structural configuration utilizing the impact energy from the dent depth meta-model. At least one design value is determined for the structural configuration based on output data generated from the computer-based simulation.

The application discloses a die forging forming method of a high-strength and high-toughness damage tolerance titanium alloy cylinder, which comprises the following steps: S1, heating raw materials; S2, primary forging; S3, surface treatment; S4, secondary forging; and S5, annealing. The method can reduce the weight of raw materials and the number of forging fires, thereby reducing the production cost, and meanwhile, can guarantee that the product has good performances and the stability of product quality is good.

The invention belongs to the field of aviation composite materials, and provides a co-curing fiber reinforced composite material for a wing girder joint. According to the invention, the design of a 1, 4-butanediol diglycidyl ether synergistic toughening flame-retardant resin system, the construction of a conductive thin felt layer double-modified by polydopamine coating and a silane coupling agent, and the design of a sandwich structure assembled by gradient regions are adopted; high Tg and low porosity of the resin matrix under a low-viscosity infiltration condition, low surface sheet resistance and strong interface combination of the modified conductive thin felt layer, and high lap joint bearing capacity and delamination damage tolerance of the gradient sandwich structure are realized; the problems that sufficient infiltration and conductive network continuity are difficult to consider in the co-curing forming process, interlayer weak plane and interface embrittlement risks are introduced by conductive flame-retardant modification, and residual stress concentration and insufficient dimensional stability are caused by high-temperature curing are solved, and the method has wide aerospace structure application value.

The application relates to a method for prolonging the service life of a turbine disc, and relates to the technical field of a turbine disc of an aero-engine. The method comprises the following steps: heating a first region of the turbine disc and heating a second region of the turbine disc; obtaining a first real-time temperature of the first region and a second real-time temperature of the second region; if the first real-time temperature reaches a first temperature threshold corresponding to the first region, stopping heating the first region; if the second real-time temperature reaches a second temperature threshold corresponding to the second region, stopping heating the second region; wherein the first temperature threshold and the second temperature threshold are different. Different temperatures are used to heat different regions of the turbine disc, so that controllable elastic-plastic deformation of the turbine disc occurs, the crack tip is blunted, the damage tolerance is improved, the fatigue life at the center hole of the turbine disc is prolonged, and the service life of the turbine disc is significantly prolonged.

The application relates to an amphibious aircraft float, a stamping die and a manufacturing method. The amphibious aircraft float is in the shape of a hull and is hot-stamped from a thermoplastic composite material composed of a thermoplastic resin and reinforcing fibers. The stamping die comprises an upper die, a lower die, a positioning device and a blank clamping device, the opposite surfaces of the upper die and the lower die are provided with male and female structures which are complementary to each other, the positioning device is fixed on the lower die, and the blank clamping device is used for clamping a blank to be stamped and is positioned by the positioning device so that the blank is positioned and supported directly above the female structure. The manufacturing method comprises the following steps: providing a stamping die, preparing a blank, heating the blank, hot-stamping and edge trimming. The amphibious aircraft float has the advantages of high strength, fatigue resistance, impact resistance and damage tolerance.

The application belongs to the technical field of non-ferrous metal processing, and particularly relates to a method for preparing high-toughness TC11 titanium alloy thick forged plate based on quasi-beta forging. Since TC11 titanium alloy has poor hardenability and it is difficult to realize the uniformity of thick forged plate structure, in order to fully tap the application potential of TC11 titanium alloy structural parts, the application involves the control and optimization of four stages of uniform two-phase material, quasi-beta forging, two-phase zone forming forging and overall heat treatment; the thickness of the TC11 titanium alloy thick forged plate prepared by using the application ranges from 50mm to 200mm, and after overall heat treatment, the impact toughness and fracture toughness and other damage tolerance properties of the forged plate are significantly improved on the premise of not significantly reducing the strength, which fully proves the application potential of TC11 titanium alloy in the field of structural parts, and provides detailed accumulation and reference for the application of TC11 titanium alloy in structural parts.

A method of analyzing a composite structure for damage tolerance. The method includes obtaining a structural configuration and determining at least one metric of interest for the structural configuration. A dent depth meta-model is developed based on the structural configuration, the at least one metric of interest, and information obtained from a machine learning algorithm. The at least one metric of interest provides a constraint for the dent depth meta-model and the machine learning algorithm is trained based on a historical physical test dataset of a plurality of composite components. The dent depth meta-model is utilized to estimate an impact energy to establish a threshold dent depth in the structural configuration. A computer-based simulation is performed with the structural configuration utilizing the impact energy from the dent depth meta-model. At least one design value is determined for the structural configuration based on output data generated from the computer-based simulation.

The present invention discloses a method for determining high stress volume under notch-defect interaction, which belongs to the technical field of damage tolerance assessment and fatigue strength prediction, comprising: calculating stress distribution data of the notch root in a component structure containing a defect notch by finite element analysis, and outputting the ratio of axial stress to nominal stress; calculating the virtual defect size of the notch component structure; using the critical distance method, combined with the ratio, calculating the stress concentration parameter of the notch root in the component structure containing the defect notch; and calculating the high stress volume area by analyzing the competitive effect of the notch and the defect, combined with the virtual defect size and stress concentration parameter. The present invention comprehensively considers the interaction between the notch and the defect, accurately calculates the high stress volume of the structure, helps to predict the fatigue failure site, and thus improves the accuracy of fatigue assessment. It is universal for structural parts with notches of any size and shape, is easy to operate, and has a wide range of applications.

The application provides a roller straightening process for improving shape, position and size of 7150 aluminum alloy profile for aviation, which adopts a straightening device for treatment; the straightening device comprises at least one lower roller piece and one upper roller piece, the lower roller piece is located below the profile, the upper roller piece is located above the profile and contacts the profile to generate a pressing amount; when the bending amount of the profile is 12-20mm in height at the head and tail, the pressing amount is 3-4mm when the hardness of the profile is 90-100HB; the pressing amount is 4-6mm when the hardness of the profile is 100-120HB; and the pressing amount is 6-8mm when the hardness of the profile is 120-140HB. According to the bending degree and hardness of the 7150 aluminum alloy profile, the pressing amount of the upper roller piece is determined in the roller straightening process, the profile is straightened under the premise of ensuring the damage tolerance of the 7150 aluminum alloy profile, so that the material can be applied in the aviation profile; and the process has the advantages of reasonable process design and easy implementation.

The invention belongs to the field of large aircraft structure design, and relates to a method for evaluating a fatigue damage detection period of a complex joint structure. The initial crack cracking mode and the crack propagation path of the complex joint structure under the combined action of multiple loads are truly simulated, the analysis precision is far higher than that of a traditional analysis method, and the method is suitable for the damage tolerance analysis method of the complex joint structure under multiple load conditions; by correcting the reference stress of crack propagation analysis and residual strength analysis on the crack cracking path, the residual strength capability of the complex joint structure is accurately analyzed, the fatigue damage detection period of the complex joint structure is evaluated, and the safety and economical efficiency of an aircraft can be improved. The method for evaluating the fatigue damage detection period of the complex joint structure is formed, and important reference basis and theoretical support are provided for large aircraft complex joint structure authentication, continuous airworthiness and the like.