49 results about "Damage tolerance" patented technology

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 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 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 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 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.

The application discloses a thermal-mechanical fatigue crack propagation rate testing method based on rigidity and crack tip strain field, comprising the following steps: firstly, a relationship function between normalized crack length and normalized rigidity is established through finite element calculation; secondly, DIC speckle preparation is carried out for observing crack propagation and strain field analysis; then, a thermal-mechanical fatigue test is carried out, crack length is calculated based on rigidity change results of the test, an a-N relationship curve is drawn combined with DIC synchronous observation results, and comparative analysis is carried out; finally, crack propagation rate is calculated through a three-point moving average secant method, and the size of a plastic zone at a crack tip is determined according to DIC strain field analysis, so that the accurate test of the crack propagation rate is realized. The application can effectively test the fatigue crack propagation behavior under the thermal-mechanical coupling effect, and accurately obtain the thermal-mechanical fatigue crack propagation rate combined with the crack tip strain field measurement method, so as to provide test data support for damage tolerance design and structure integrity evaluation of high-temperature pressure-bearing equipment.

The invention relates to a method for constructing a hole surface defect distribution curve for probabilistic damage tolerance evaluation. The method comprises the following steps: preparing a tested piece with a hole; performing a low-cycle fatigue test on the tested piece under different loading conditions to obtain the low-cycle fatigue life of the tested piece; deducing an equivalent initial defect size based on crack propagation analysis by using the loading condition and the low-cycle fatigue life of the tested piece as constraints; fitting the equivalent initial defect size according to extreme value distribution to obtain a defect size distribution curve; the defect size distribution curve is used for obtaining the defect occurrence rate through a probability damage tolerance evaluation example; and combining the defect size distribution curve and the defect occurrence rate to obtain the hole surface defect distribution curve.

The invention discloses a pre-embedded hollow insert for a composite material connecting structure and a preparation process of the pre-embedded hollow insert, and belongs to the technical field of composite material connection. The pre-embedded hollow insert comprises an insert inner ring and a pre-embedded structure arranged on the outer edge of the insert inner ring in the circumferential direction; wherein the insert inner ring is in contact with the fastener and bears a compression load, and the embedded structure is annular, is provided with a hollow structure, is combined with the composite material laminated board and transmits a shear load. The method comprises the following steps: firstly, placing an insert in a bolt hole position in a composite prepreg laying process, forming through connection between upper and lower prepregs, and enabling resin to permeate and realize interlayer lap joint in a curing forming process through a hollow area, so as to enhance the bonding strength of the insert and the composite material; after forming, the fastener is fixed through the insert inner ring, compression load is effectively converted into interlayer shear load, and hole edge stress concentration and premature failure are avoided. The bearing capacity and the damage tolerance of the composite material connecting structure are improved, and the composite material connecting structure is suitable for lightweight connecting structure design of aerospace, automobiles and high-performance equipment.

The application belongs to the technical field of impact damage tolerance evaluation of fiber reinforced resin matrix composite structure, and particularly relates to a composite material residual strength prediction method based on intelligent reconstruction. A gray-scale image of a damaged area is divided into multiple damage images according to different gray-scale values; a damage contour of the composite material in the damage image is identified, the position information of the damage contour in the thickness direction of the composite material is determined according to the gray-scale value of the damage contour, and the damage contour is coordinated; the damage contour of all damage images is gridded according to the damage contour coordinates; the gridded coordinates of all damage contours are introduced into a pre-established finite element model of the composite material according to the corresponding position information, and the finite element model is three-dimensionally numerically reconstructed; the three-dimensionally numerically reconstructed finite element model is stiffness-decayed according to the damage area distribution characteristics of the three-dimensionally numerically reconstructed finite element model; and the residual strength of the stiffness-decayed finite element model is predicted by using a finite element method.

The application discloses a method for evaluating damage tolerance and residual life of a track element at a non-wheel-rail contact position of a turnout area, obtains a sample material of a non-wheel-rail rolling contact area of a turnout track element, and obtains crack propagation data of the sample material through testing to fit Paris formula parameters. Then, finite element stress analysis of the turnout track element is carried out, the result file is imported into crack analysis software, and a crack is inserted at the non-wheel-rail rolling contact position of the track element to obtain a crack analysis model of the non-wheel-rail contact position part of the turnout track element. Finally, crack propagation simulation is carried out, the formula parameters are imported into the crack analysis software, and crack propagation simulation is carried out to obtain a calculated life. Indoor full-scale model verification is carried out, the calculated life is compared with an actual life, and it is confirmed whether the parameters and the model are accurate. If the parameters and the model are accurate, residual life of the turnout track element at the non-wheel-rail contact area is evaluated according to the model and the parameters. The application can save maintenance costs based on damage tolerance and residual life, and better guarantee the safety of railway operation.

The invention belongs to the field of aircraft structure design and strength analysis, and particularly relates to a titanium hybrid material three-layer damage safety lug reliability calculation and analysis method which combines a rigidity design criterion and a damage tolerance analysis method of a multi-force transmission path lug structure on the theoretical basis of a load sharing parallel system. A load sharing principle and a life equivalence principle are determined, and a basis is provided for life equivalent conversion. For a multi-force-transmission-path lug structure, the reliable working condition of the lug structure can be divided into three layers of unfailed lugs, one layer of failed lugs and two layers of failed lugs, the reliability of the lug structure is the sum of the occurrence probabilities of the three conditions, and the calculation method is elaborated in detail.

The invention discloses a wind power main shaft and a manufacturing method for improving the anti-fatigue performance of the wind power main shaft, and belongs to the technical field of manufacturing of key components of wind power generation equipment. The method comprises the following steps that a medium carbon alloy steel ingot is subjected to multidirectional upsetting and drawing forging, and a forging stock is obtained; the forging stock is subjected to cryogenic pretreatment and then heated to the room temperature; and then composite quenching and tempering heat treatment, surface composite strengthening treatment and low-temperature aging treatment are conducted in sequence. The method is easy to operate, the fatigue life of the wind power main shaft can be effectively prolonged, the fatigue life can be prolonged by 50%-100% compared with the fatigue life of a wind power main shaft manufactured through a traditional process, and the damage tolerance and safety reliability of the wind power main shaft under the severe working condition can be greatly improved.

: A solar array system for spacecraft includes a motorized central column of rigid panels and flexible outer flip-out panels. Each central hinge module is motor-driven and rigidizes when deployed. Flip-out panels may deploy passively or via motorized hinges, and are constrained from deployment until the central column completes deployment. A keep-alive panel is exposed while stowed, providing early power generation. The system enables modular manufacturing, damage tolerance, and efficient packing for launch.