227 results about "Residual strength" patented technology

A system and method for automatically varying the flight envelope of an aircraft based upon the material health of the aircraft and the flight environment is provided. The system includes a plurality of structural health monitoring and load sensors that determine the approximate size and the approximate location of the damage. The system performs residual strength calculations for individual aircraft components to determine the overall aircraft residual strength. The system uses these calculations to determine a maximum flight envelope based on the overall aircraft residual strength, and transmits this information to the flight controller and optionally to the pilot.

The invention discloses a metal complex low-carbon magnesia carbon brick used for ladle slag lines, the weight percentage of the added materials is as following, 50 to 70 percent of magnesia particles, 25 to 35 percent of magnesia powder, and 3 to 6 percent of organic binder, furthermore, the following components are added which are produced by mixing, striating materials, forming and heat-treatment, 0 to 4 percent of flake graphite, 3 to 15 percent of metal powder, and 0.5 to 3 percent of antioxidant containing boron. The antioxidant properties, slag-resistance performance, high temperature strength and the thermal shock resistance of the ladle slag line used metal complex low-carbon magnesia carbon brick are greatly improved, the service life is prolonged, the consumption cost of each ton of refractories is lowered. The preparation method of ladle slag line used metal complex low-carbon magnesia carbon bricks is also disclosed, and the carbon content in the ladle slag line used metal complex low-carbon magnesia carbon bricks produced by the method is less than or equal to 6 percent, little carbon is added so as to reduce the pollution towards liquid steel, and residual strength ratio of the thermal shock resistance is kept at 70 to 80 percent.

The invention pertains to airplane fatigue and damage-tolerance testing technologies, and relates to a damage-tolerance testing method for the whole wing spar of an airplane. The method comprises the steps of: (I) choosing a part with large load from the whole wing spar for serving as a testing part examining segment, (II) producing two same testing parts according to the examining segment, (III) reserving an interval of 20 to 30mm between the two back-to-back testing parts which are respectively provided with a coating in the upper part and the lower part (the coating is connected with an upper spar edge strip and a lower spar edge strip to form a case segment), (IV) fixing the root of the testing case segment completing assembly on a load-bearing wall, (V) exerting concentrated load at one end of the testing parts to simulate the bending moment of the spar at the testing segment and the shearing force of a web, without considering the influence of the shearing flow of the coating and (VI) using a finite element method to conduct damage tolerance analysis on the testing parts and comparing testing results. The method solves the difficulty that the crack expansion and remaining strength of the present airplane whole wing spar structure lack theoretical evidence; and the design of the testing parts adopts a method of simultaneously conducting tests to the two back-to-back testing parts, thereby eliminating the distortion of a single spar.

The invention discloses a method for analyzing the mechanical property of a UD-CMC (Unidirectional Ceramic Matrix Composite) under a stress oxidation environment. The method comprises the following steps: determining the crack number, which changes along with stress, of a base of the UD-CMC; determining a crack width change rule; determining influence of cracking of the base of the UD-CMC on the change of a mass weight-loss ratio lambda by considering a stress reaction according to an oxidation mechanism of the UD-CMC under an existing unstressed oxidation environment of 400 to 900 DEG C; determining a change rule of residual modulus of the UD-CMC under a stress oxidation environment by considering the situation that the base of the UD-CMC cracks; determining a change situation of residual strength of the UD-CMC under the stress oxidation environment by considering the situation that the base cracks according to a change rule of the volume fraction of the UD-CMC. According to the method for analyzing the mechanical property of the UD-CMC under the stress oxidation environment, disclosed by the invention, a relevant theoretical support is provided for analyzing the mechanical property of the UD-CMC under the stress oxidation environment.

The invention discloses a method for predicting the residual intensity and the residual service life rapidly and intactly, comprising the following steps that: firstly, the stress-service life curve of a material or a part, i.e. the S-N curve, is measured; secondly, the corresponding relation between the surface hardness and the residual intensity of the material or the part under a random load spectrum of reinforcing, damaging and considering small load strengthening is established; thirdly, the surface hardness in the process of using the material or the part is measured, according to the corresponding relation between the surface hardness and the residual intensity of the material or the part, the residual intensity of the material or the part is predicted rapidly and intactly; forthly, the residual service life of the material or the part under the different load spectrum is predicted rapidly and intactly by adopting the predicted residual intensity and the stress-service life curve of the material or the part, that is the S-N curve. The rapid and intact prediction of the residual intensity and the residual service life of the material or the part can be realized by the simple measurement of the surface hardness by adopting the method.

When stiffening members, such as stringers and frame members, are welded onto a skin sheet to form an aircraft fuselage shell, a crack originating in the skin sheet tends to propagate through the weld joints into the stiffening members. In order to prevent crack propagation into a stiffening member, the stiffening member is reinforced with a web doubler plate or a tension band made of high strength steel or titanium alloys or fiber-reinforced composites. The doubler plate is riveted or adhesively bonded onto a stiffening member web, or the tension band is crimped into the stiffening member web. The resulting fuselage shell structure has crack stopping properties and thus an increased residual strength, so it can be used with welded joints at all areas of the fuselage shell, including the top and sides as well as the bottom of the fuselage.

The invention discloses a rock-soil pressure shear rheological testing machine and a testing method, the testing machine comprises a mainframe, a vertical loading system and a horizontal loading system are provided on the mainframe, and a servo oil pressure system controlled by a computer provides oil pressure to the vertical loading system and the horizontal loading system. According to the invention, a shearing apparatus, the horizontal loading system, a servo hydraulic system and an electric control system are added for realizing automation, control and accuracy of the tests. An original waste and old press mainframe and a vertical oil cylinder are used by the testing machine, thereby about 50% of cost can be saved, the testing machine aims at test materials such as rock, rock mass and soil/stone compound body, and can perform with the following tests: a compression test, a shearing test, a residual strength shearing test, a compression rheological and shearing rheological test.

The invention discloses a residual intensity and residual life computing method for pipe gallery pipelines. The residual intensity and residual life computing method comprises the following steps: collecting the data information of defects of the pipe gallery pipelines; judging the defects are plane type defects or volume type defects; for the plane type defects, obtaining the engineering stress-strain curve of a defect pipeline material from the data information of the defects of the pipe gallery pipelines, determining a failure assessment diagram, and then computing assessment points to obtain the residual intensity of the pipe gallery pipelines; for the volume type defects, obtaining the design factors, the weld joint factors and the minimum measurement wall thickness from the data information of the defects of the pipe gallery pipelines, and obtaining the residual intensity of the pipe gallery pipelines through computing; computing basic numerical values according to the data information of the defects of the pipe gallery pipelines, and computing the residual lives of the pipe gallery pipelines according to a maximum value distribution probability density function, a reliability function, maximum corrosion depth point estimation and maximum likelihood estimation. Therefore, the residual intensity and residual lives of the pipelines in a pipe gallery area are effectively and accurately computed and predicted.

The invention relates to a method for determining allowable defects of a helicopter composite main rotor blade and belongs to the technical field of structural fatigue design of helicopters. The method comprises the following steps: determining forms and easily occurring areas of a defect according to the function and structure of each area of a main rotor blade and process control and other conditions in the manufacturing process; predicting the maximum allowable size of the defect based on the principles such as detection simplicity, statistics and process controllability, and prefabricating on a full-sized test piece; determining the rationality of defect parameters by adopting a test of simulating fatigue and residual strength in a real load environment, determining the defect types in critical prevention and control of the composite main rotor blade, and establishing the defect allowable standard. According to the method, a technical basis can be provided for treatment of the various defects in the production, usage and maintenance processes.

The invention relates to an evaluation method of residual strength and service life under strengthening and damaging combined action, which is characterized in that: (A) virtual stress-life curve of a material or a part is obtained by test or technical resources, and the fatigue strength and low amplitude loading range are determined; (B) the low-load strengthening general rule of the material or the part with different strength grades are built according to low-load strengthening performance data of low-strength and high-strength materials or parts by virtue of a numerical method of spline interpolation; (C) the fatigue strength changing rule is built according to the stress-life curve of the material or the part under the strengthening and damaging combined action; in addition, according to the loading grade and frequency of a loading spectrum, the instantaneous fatigue strength value, that is, the residual fatigue strength of the part with given using mileage is calculated; (D) according to the instantaneous stress-life curve, the life evaluation of the material or the part is carried out according to Miner linear damage theory. The invention provides a specific method for the service life of the part and the light-weight design.

An apparatus and method for inspecting and calculating the residual strength of an aramid fiber rope driving an elevator to determine when such rope is in need of replacement. The apparatus comprises a transmitter for introducing an acoustic wave that will travel along the aramid fiber rope and a plurality of receivers for receiving the acoustic wave after its has traversed a designated section of the rope. The transmitter and receiver provide signals indicating the times the wave was sent by the transmitter and thereafter received by the receiver. From these signals, a program calculates the wave velocity, and the modulus and residual strength of the aramid rope.

The invention discloses a method for assessing residual intensities of composite material structures with low-speed impact damage. The method comprises six steps of: 1, obtaining a curve relationship between impact energy and damage characteristic parameters through low-speed impact test results; 2, obtaining a maximum contact force and a maximum pit depth under corresponding impact energy by adoption of an impact damage theory; 3, establishing a low-speed impact progressive damage finite element model; 4, correcting the low-speed impact progressive damage finite element model; 5, establishing a residual intensity finite element model with impact damage; and 6, solving the residual intensity finite element model with the impact damage to obtain a residual intensity value. According to the method disclosed by the invention, finite element simulation is applied to impact damage models, and the impact test results and the impact damage theory are combined, so that the accurate simulation for damage states, the accurate building of finite element models with initial impact damage and the continuity of assessment processes are realized, and a relatively high practical value is provided.

The invention discloses a structural health monitoring system for an aircraft. The structural health monitoring system comprises a sensor network for providing sensor signals to each subsystem; a first subsystem for carrying out quantitative monitoring on multiple damage of a large-size aviation structure; a second subsystem for monitoring tiny cracks in a high-stress area of an aviation metal structure and monitoring the damage of delamination, debinding and fibre breakage and the like in the high-stress area of an aviation composite material structure; a third subsystem for carrying out positioning on external bumping of the aviation composite material structure and load reconstruction; a fourth subsystem for carrying out distributed real-time measurement on strain of a key area of the aviation structure and corresponding load reconstruction; a fifth subsystem for carrying out prediction on the service life and residual intensity of the aviation structure; and a sixth subsystem for controlling and coordinating the work of the other subsystems. The structural health monitoring system provided in the embodiment of the invention overcomes the defect that the function of a conventional aircraft structure health monitoring system is single.

The invention discloses a method for verifying the bird strike resistance performance of a pitch link of a main blade of a helicopter, and belongs to the field of helicopter structural strength tests. The method is used for determining the performance of the pitch link of the main blade of the helicopter after bird strike damage is generated in the flight process. Aiming at the characteristics that the pitch link of the main blade of the helicopter is high in bird strike probability in low airspace, and damage is serous, the bird strike resistance performance of this kind structures is assessed accurately through the bird strike tests of the full size structure under simulated real working environment, fatigue life verification tests half hour after striking and residual strength tests, and it is guaranteed that catastrophic results cannot be generated even if bird strike occurs to the helicopter in the harshest flight process.

The invention discloses a microbial curing-fiber reinforcement combined sandy soil modification method and belongs to the field of geological engineering-microbial interdiscipline. The method comprises the steps as follows: 1) adding a fiber material to sandy soil, adding water, performing uniform stirring, putting the mixture in a mold, and leaving the mixture to stand and drying the mixture after compacting and filling the mold; 2) activating a microbial solution with mineralization; 3) soaking the sandy soil in the activated microbial solution; 4) transferring the treated sandy soil to a maintenance device, and filling the maintenance with a gluing solution for gluing and curing. An MICP technology and a fiber reinforcement technology are combined to modify the sand soil, so that loosesandy soil is cured, the forming strength is improved, meanwhile, brittleness of a sandy soil cured body can be significantly reduced and residual strength and toughness of the sandy soil cured body can be improved due to addition of the fiber, the engineering properties of traditional MICP cured sandy soil are improved as a whole, and the method has great significance in further improving safetyand stability of engineering structures.

The invention discloses a method for determining allowable defects of a honeycomb sandwich layer of a helicopter, belongs to the technical field of structural fatigue design of helicopters and particularly relates to a method for determining honeycomb sandwich layer structure defects of a helicopter body with defects. By prearranging internal and external defects on a honeycomb sandwich layer test piece and determining the rationality of defect parameters by adopting static strength, fatigue and remaining strength comparative tests under real load-bearing environments, bases are provided for the design and handling of such manufacturing deviations, the manufacturing and using costs of the honeycomb sandwich layer structure can be decreased and the risk in use of the defective structure is reduced.

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

The invention relates to a strain control method for measuring residual strength and residual service life of a composite material. The strain control method comprises three steps of (1) a strain control residual strength model; (2) a random model of the strain control residual strength; and (3) model parameter estimation. The strain control method is simple and practical, is convenient for operations and has high calculation precision. The strain control method has relatively good practical value and wide application prospects in the field of measurement technology.

The present invention relates to a robotic pipeline inspection device that measures the residual strength of the pipe. Aging underground infrastructure is a major problem around the globe. There is a need for a deterministic, non-destructive, pipeline condition assessment device. Some of the other internal pipeline inspection devices work well, but the data obtained by using them is limited to thickness of the pipe or internal video of the pipeline. The invention presented herein can send and receive ultrasonic pulse into the pipe wall within millimeters, thereby, determining the residual strength of the pipe material. The embodiment of the present invention provides a pipeline inspection device comprising: a body comprising mounted wheels; a transducer and receiver connected to the body; at least one motor to power the wheels and the transducer and receiver; and wiring that connects the transducer and receiver to the at least one motor.