61 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 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 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.

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 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.

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 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.

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.

The utility model discloses an exhaust pipe, an engine and a vehicle. The exhaust pipe comprises an exhaust pipe body, a supercharger flange and a crack arrest hole formed in the end face of the supercharger flange. The supercharger flange is connected to the exhaust pipe body and used for installing a supercharger of an engine. The supercharger flange is provided with a through hole, and the supercharger flange communicates with the exhaust pipe body through the through hole to form an exhaust passage; a middle partition plate extending to the end face of the supercharger flange is arranged in the exhaust passage and divides the exhaust passage into a first exhaust passage and a second exhaust passage. A first connecting position and a second connecting position are arranged between the middle partition plate and the supercharger flange in the direction perpendicular to the arrangement direction of the first exhaust channel and the second exhaust channel. The crack arrest hole is formed in the first connecting position; and / or the crack arrest hole is formed in the second connecting position. The exhaust pipe can control the crack propagation direction and length of the exhaust pipe supercharger flange, the damage tolerance characteristic of the exhaust pipe is improved, and the service life of the exhaust pipe is prolonged.

The invention discloses a blade damage tolerance threshold determination method based on aerodynamic performance simulation and related equipment. The method comprises the following steps: firstly, establishing a blade model library containing multiple preset damage levels; on the basis, planning the spatial distribution of different types of damaged blades on the bladed disk, and constructing a serialized bladed disk model set containing the combination of total damage and mixed damage; then, carrying out system pneumatic simulation on each bladed disc model, extracting key parameters such as flow and pressure ratio, and calculating the deviation ratio of the key parameters relative to a non-destructive reference, so as to form an integrity performance database associated with damage degree, quantity, distribution and performance change; and finally, whether aerodynamic performance degradation in different damage states exceeds a preset permission range is analyzed based on the database, so that a scientific and quantitative damage permission threshold judgment basis for guiding a maintenance decision is generated.

The invention provides an aero-engine maintenance interval time design method and a computer readable storage medium. The method comprises the following steps: dividing parts of the aero-engine into safety key parts and non-safety key parts; calculating a safety cycle service life value of the safety key component based on a safety life method, and calculating a safety cycle service life value of the non-safety key component based on a damage tolerance method; calculating a safety cycle service life value for verification of each component, and verifying the safety cycle service life value of each component by using the safety cycle service life value for verification; if yes, adjusting parameters in the safe life method or the damage tolerance method or adjusting parameters adopted in calculation of the safe cycle service life value for verification until the safe cycle service life value conforms to the safe cycle service life value for verification; and determining the actual maintenance interval time according to the verified safe cycle service life value.

The application discloses a crack tip cracking prediction method and system for ductile metal materials, which can accurately characterize the strain energy density distribution of the crack tip of a ductile metal structure, and accurately and quantitatively characterize the crack initiation criterion verification and damage tolerance fatigue life prediction of the crack tip. The method comprises the following steps: obtaining the strain field of the crack tip of the ductile metal material to be measured based on DIC technology; constructing a constitutive model of the ductile metal material to be measured based on a uniaxial tensile test; calculating and obtaining the stress field of the crack tip of the ductile metal material to be measured according to the strain field and the constitutive model based on plastic deformation theory and Newton-Raphson iteration algorithm; calculating the elastic strain energy density field and the plastic strain energy density field of the crack tip of the ductile metal material to be measured according to the obtained stress field and strain field, and obtaining the critical plastic strain energy; and predicting the cracking of the crack tip of the ductile metal material to be measured according to the critical plastic strain energy.

Embodiments of the present application provide a kind of fracture toughness determination method, device, machine readable storage medium and computing device, belong to mechanical property testing technical field.The method comprises: obtaining the load-crack nozzle opening displacement curve when target material carries out CTOD test;Each coordinate point on load-crack nozzle opening displacement curve is regularized to obtain J-R resistance curve;The toughness tear amount of target material is obtained, and the offset line is determined based on toughness tear amount;Determine the first CTOD value based on the intersection point corresponding to target J integral of offset line and J-R resistance curve;Linear fitting is carried out based on the first CTOD value and toughness tear amount to obtain fitting straight line;The apparent fracture toughness value of target material is determined based on fitting straight line.From the definition of apparent fracture toughness, the accuracy of fracture toughness calculation for different materials is improved.And by quantitative calculation apparent fracture toughness, provide reference basis for accurate material selection, damage tolerance design and life assessment.

The invention relates to a method for constructing a powder defect distribution curve for probabilistic damage tolerance evaluation. The method comprises the following steps: carrying out a fatigue test on a test bar with an examination section; performing fracture analysis on the fractured examination section to at least obtain the defect size, the defect type and the defect number of all defects; fitting the obtained defect size according to extreme value distribution to form a defect size distribution curve; calculating a defect occurrence rate according to the number of defects and the volume of the examination section; and combining the defect size distribution curve and the defect occurrence rate to obtain the powder defect distribution curve.

This invention discloses a biomimetic dual-scale lattice metamaterial with high damage tolerance and electromagnetic absorption performance, and its design method. It belongs to the field of integrated design technology of damage tolerance design and electromagnetic function. This invention uses finite element simulation software, based on a first-order unit lattice, and adopts a recursive modeling method to design a second-order dual-scale lattice structure. By rationally designing the topology and size parameters of the dual-scale lattice, the structure maintains a high electromagnetic absorption rate over a wide frequency range, improves the damage tolerance of the structure, and, while maintaining a low relative density, makes it have high specific stiffness and specific strength, thus achieving mechanical-electromagnetic integrated optimization.

The invention discloses a composite insert for enhancing hole edge strength and a using method thereof, and belongs to the technical field of composite structure connection. The hole edge insert has rotational symmetry or spiral geometric characteristics and comprises a limiting structure, an insert inner ring, a self-rotating structure and an insert outer ring, wherein the insert inner ring, the self-rotating structure and the insert outer ring are used in combination with the limiting structure and are integrated. The method comprises the steps that firstly, a hole edge rigidity adjusting insert with a self-rotating structure is designed, and a bolt hole is subjected to chambering treatment; secondly, the insert is embedded into the hole in an interference fit mode and connected with the unthreaded section of the bolt; thirdly, the composite material laminated board and the metal plate are assembled to form a multi-bolt lap joint structure; in the service process of the structure, the spinning structure in the insert generates controllable deformation under the action of external load, the hole edge rigidity is dynamically adjusted, and balanced transmission of loads among multiple bolts is achieved. By introducing the rigidity-adjustable structural unit, local stress concentration is effectively reduced, the damage tolerance and mechanical stability of the connecting structure are improved, and the connecting structure has good engineering applicability and popularization prospects.