378 results about "Stress relaxation" patented technology

The invention discloses a cultural relic preventive protection method based on big data analysis, belongs to the technical field of cultural relic protection, and mainly aims to solve the technical problem that a complex damage mechanism caused by mutual coupling of torsional deformation and inclined deformation in cultural relic protection is difficult to accurately predict. A dual-mode deformation data stream is obtained through a multi-point sensor, accurate data alignment is achieved through millisecond-level time synchronization processing, and correlation characteristics between deformation modes are recognized by calculating a coupling strength coefficient through correlation analysis. And when the coupling strength exceeds a threshold value, determining a deformation propagation direction vector by combining a spatial interpolation method, and calculating an internal stress distribution field and positioning a stress concentration area by utilizing a finite difference method. High-frequency sampling tracking is carried out on the high-risk area, and a stress relaxation time constant and a creep coefficient are obtained. Accurate prediction and active protection of cultural relic deformation damage are realized.

An austenitic stainless steel material is provided that has high creep strength even when used at an average operation temperature of more than 600 to 750° C. after welding with higher heat input, and furthermore, has excellent stress relaxation cracking resistance even after use for a long time period at the average operation temperature after welding with higher heat input. The steel material has a chemical composition which consists of, in mass %, C: 0.030% or less, Si: 1.50% or less, Mn: 2.00% or less, P: 0.045% or less, S: 0.0300% or less, Cr: 15.00 to 25.00%, Ni: 8.00 to 20.00%, N: 0.050 to 0.250%, Nb: 0.10 to 1.00%, Mo: 0.05 to 5.00%, and B: 0.0005 to 0.0100%, with the balance being Fe and impurities, and a ratio of the dissolved N amount (mass %) with respect to the content of N (mass %) in the steel material is 0.40 to 0.90.

The invention discloses a ten-thousand-square-meter muddy deep foundation pit supporting structure deformation prediction method which comprises the following steps: establishing a soil-supporting interaction rheological model, simulating stress relaxation and creep effects of muddy soil in combination with a Burgers rheological model, and realizing dynamic evolution prediction of a supporting structure deformation field and an internal force field. According to the method, the particle filter algorithm is adopted to carry out denoising processing on real-time monitoring data, model parameters are updated through the Bayesian method, and the prediction precision is improved. Meanwhile, nonlinear mapping of the deformation rate and the internal force increment is established by using a random forest algorithm, and instability risk probability distribution is generated. According to the method, multi-stage collapse early warning thresholds are set, monitoring data and prediction results are fused by adopting a weighted average method, and abnormal points of a high-risk area are identified. For a high-risk area, a genetic algorithm is applied to optimize the rigidity and prestress distribution of a supporting system, effective control over deformation and internal force of a supporting structure is achieved by dynamically adjusting construction parameters, and construction safety of the deep foundation pit is ensured.

The invention discloses a light-weight manufacturing method and system for a PET bottle for food packaging, particularly relates to the technical field of PET bottle blank manufacturing, and aims to solve the problem that the subsequent blow molding quality is affected due to the fact that complex internal stress is generated in a bottle blank due to a rapid cooling process after injection molding in the prior art. Image information and temperature distribution data of a bottle blank after injection molding are obtained, geometric features and cooling rate differences are analyzed and recognized based on multi-physics coupling, a stress cause weight evaluation model is established to generate a stress distribution map, and then structural entropy increase factors under different temperature adjustment paths are simulated and calculated according to thermodynamic parameters, so that the temperature adjustment precision is improved. And carrying out partitioned temperature adjustment treatment on the bottle blank, and finally, carrying out constant-temperature and constant-humidity standing to sufficiently relax the stress. The internal stress distribution of the bottle blank can be effectively controlled, and the wall thickness uniformity and the mechanical property consistency of the light-weight PET bottle are improved.

The invention provides a data processing method and system based on intelligent construction, and relates to the technical field of intelligent construction.The method comprises the steps that viscosity, a temperature peak value, temperature and humidity and time delay distortion data in the solidification stage are collected in real time in the concrete pouring construction process, and a material stress relaxation model is constructed to calculate three-dimensional stress distribution; meanwhile, mapping sound wave time delay distortion data into a spatial topological graph, and extracting propagation anomaly features by using a space-time graph convolutional network; and generating a crack risk distribution diagram by fusing stress distribution and abnormal characteristics, and finally, accurately positioning a potential defect area according to risk gradient change. The early warning capability of concrete construction quality defects is improved.

The invention relates to a preparation method of beryllium-copper alloy. The preparation method comprises the following steps: (S1) accurately weighing the following raw materials by mass: copper, beryllium, copper-yttrium alloy, copper-titanium alloy, copper-manganese alloy and nano ytterbium powder; (S2) the raw materials are added into a vacuum induction furnace, the temperature is increased to 1400-1600 DEG C under the inert atmosphere, after the raw materials are completely molten, a covering agent is spread on the melt, smelting, standing and slagging-off are conducted under the stirring condition, the melt is poured into a mold under the condition of 1100-1200 DEG C, and a beryllium copper alloy ingot is obtained; and (S3) the beryllium-copper alloy ingot is subjected to face milling treatment, solution treatment, cold machining deformation treatment and aging treatment in sequence, and the product beryllium-copper alloy is obtained. A small amount of metal elements are added, aging treatment is carried out under the microwave condition, and then slow cooling is carried out at the constant cooling rate, so that the overaging phenomenon can be remarkably inhibited, the hardness of the alloy is improved, and meanwhile, the mechanical property, especially the stress relaxation resistance, is also improved.

The utility model provides a steel wire stress relaxation testing machine which comprises a base plate, a stress testing mechanism used for pulling a steel wire is arranged on the base plate, and the stress testing mechanism comprises two-way moving platforms arranged on the left side and the right side of the base plate. The two bidirectional moving platforms are each provided with a clamping assembly used for clamping and fixing a steel wire, and an adsorption assembly used for adsorbing the broken steel wire is arranged below the clamping assemblies and located on the base plate. According to the utility model, a snapped steel wire can be adsorbed and fixed through the adsorption assembly, so that the problems that the surfaces of most testing machines are not provided with protection measures, fractures are likely to splash all around along with the snapping of metal materials such as steel wires and steel strands in an experiment process, and the testing efficiency is increased are solved. And certain body injuries can be caused to experimenters.

The invention discloses a tensile total strain energy density-based life prediction method considering a stress relaxation effect, which comprises the following steps of: firstly, performing tests in a strain control mode at the same temperature to obtain mechanical response parameters and test life of a material in each test in a half-life cycle, and then calculating the tensile total strain energy density based on the mechanical response in a load holding stage. Fitting a stress relaxation model, representing the inelastic strain energy density caused by various loads by taking the area under each region of a half-life cycle hysteresis loop as a damage parameter, meanwhile, considering the complex effect of a material, correcting the influence of average stress on the life, and finally, establishing a life prediction model based on a strain energy density-frequency separation method. And the fatigue-creep life prediction is realized. The model of the method can comprehensively consider the influence of various important factors such as stress relaxation, loading waveform, loading frequency, average stress and the like on the service life, and the area of the hysteresis loop serves as a damage parameter, so that the model has certain physical significance and has high universality in practical engineering application.

To provide a setting method of an approximate equation of an equivalent elastic modulus of spray concrete, capable of identifying an equivalent elastic modulus of the spray concrete with accuracy in which actual phenomenon can be reflected, and a design method of timbering of a mountain tunnel.SOLUTION: A setting method of an approximate equation of an equivalent elastic modulus of spray concrete, comprises: an A step for performing multi-stage stress relaxing test, to a sample of the spray concrete; a B step for executing reproduction analysis for reproducing a stress-time relationship; a C step for executing successive digging analysis of the tunnel; and a D step for setting an equivalent elastic modulus, from a stress-strain relationship of a spray concrete model which is determined by the digging analysis of the tunnel. In the C and D steps, to at least one of parameters formed of a tunnel diameter, an elastic coefficient of natural ground, a cycle time, and intensity of the spray concrete, the successive digging analysis of the tunnel is executed by parametric study, and on the basis of the analysis result, an approximate equation of the equivalent elastic modulus being at least one function in parameters, is created.SELECTED DRAWING: Figure 1

The invention discloses an invasion limit surrounding rock excavation method for a large deformation section of soft rock, and relates to the technical field of invasion limit surrounding rock excavation construction for the large deformation section of the soft rock. The invasion limit surrounding rock excavation method for the large deformation section of the soft rock comprises the steps that refined partitioning of an invasion limit body is achieved through dense scanning and loose circle testing; dividing the invasion limiting body into a core pressure-bearing area and a peripheral stress relaxation area; a main stress diversion arch crossing an invasion limit section is constructed through full-ring radial grouting reinforcement and erection of a strong profile steel temporary cover arch, and effective stress transfer is achieved; the mode of subarea gradual type dismantling and chiseling and instant supporting is adopted, a peripheral stress relaxation area is treated firstly, then a core pressure-bearing area is treated, and surrounding rock disturbance is reduced; the circumferential stress equalization is realized by compensating grouting in stages and dynamically adjusting the grouting pressure according to real-time monitoring data. According to the method, the excavation construction safety of the invasion limit surrounding rock of the large deformation section of the soft rock can be improved, surrounding rock disturbance is reduced, stress distribution is optimized, and the treatment efficiency of the invasion limit surrounding rock is improved.

The invention provides a stress relaxation resistant low beryllium copper alloy and a preparation method thereof, and belongs to the technical field of alloys. The stress relaxation resistant low beryllium copper alloy is prepared from the following components in percentage by mass: 0.1 to 0.5 percent of Be, 0.1 to 0.5 percent of Co, 0.1 to 0.3 percent of Sn and the balance of Cu. The Sn element and the Co element are added, and a Cottrel air mass can be formed by utilizing Sn atoms and Co atoms to hinder dislocation motion, so that the stress relaxation resistance is improved. The result of the embodiment shows that the stress relaxation rate of the low-beryllium copper alloy is kept at about 10% in the whole test period, the low-beryllium copper alloy has excellent stress relaxation resistance, meanwhile, the tensile strength of the alloy can reach 750-800 MPa, the hardness of the alloy is 240-260 HV, the conductivity of the alloy is 52-55% IACS, and the low-beryllium copper alloy has high strength, high conductivity and excellent stress relaxation resistance.

The invention discloses a heavy-duty gas turbine blade creep fatigue life design method considering an anisotropic effect, and relates to the technical field of gas turbine key component creep fatigue life evaluation.The method comprises the steps that orientation factor parameters on characteristic orientation are determined based on tensile data on [001] crystal orientation; constructing a modified stress relaxation formula; constructing an anisotropic failure strain energy density equation based on the pure creep performance data and the orientation factor parameters, and determining an upper platform of failure inelastic strain energy density on [001] crystal orientation; further determining an upper platform of the failure inelastic strain energy density on the feature orientation; constructing a creep damage prediction model based on a modified stress relaxation formula and an anisotropic failure strain energy density equation; and adopting the creep damage prediction model to obtain the creep fatigue life of the anisotropic turbine blade material sample. The method meets the actual requirements of service life evaluation of the high-temperature part of the heavy-duty gas turbine.

The invention relates to the technical field of material preparation, and discloses a nano-composite construction preparation method and system for a high-flexibility display film, and the method comprises the steps: setting a composite construction sequence corresponding to a nano-composite material; calculating the interface coupling bonding strength of the nano composite material in the compounding process, calculating the deformation adaptation coefficient of the display film substrate in the compounding process, and analyzing the dynamic synergistic compounding efficiency of the nano composite material; thermal gradient distribution data and pressure load data of the nanocomposite in the construction process are recorded, the stress relaxation rate in the display film after construction is completed is calculated, the uniform attenuation coefficient of the interlayer structure of the display film is calculated, and the multi-dimensional structure stability performance of the display film is evaluated; and determining a composite gradient distribution strategy of the nano composite material, formulating preparation process parameters of the display film in nano composite construction, and executing composite construction preparation of the nano composite material to obtain a finished product of the high-flexibility display film. According to the invention, the quality stability of the preparation of the high-flexibility display film can be improved.

The invention discloses a multi-material structure topological optimization method capable of accurately predicting and controlling stress, which comprises the following steps of: introducing multi-material prediction density and a multi-material transformation factor in a step of relaxing stress constraint of a material sub-domain to realize accurate prediction and control on the stress constraint of the multi-material, and solving the stress field when solving the stress field. A Heaviside function is adopted to carry out large-force mapping on the filtering density, the multi-material prediction density is obtained, the number of gray units is smaller than that of physical density, the structural gray change degree in the iteration process is remarkably reduced, a linear or nonlinear stiffness matrix calculation mode can be adaptively selected according to the proportion of the gray units in a design domain, and the multi-material prediction density is obtained. The stress calculation precision is improved; meanwhile, different from a traditional regularization method which adopts a maximum stress value in a design domain in an iteration process to calculate the stress relaxation coefficient, the stress relaxation coefficient is calculated by adopting a maximum predicted stress value of each material sub-domain in the iteration process aiming at basic characteristics of multi-material topological optimization, and accurate control on the maximum stress in the design domain is realized.

The invention provides an aluminum alloy door and window seamless welding system, which belongs to the technical field of door and window welding, and comprises a machine table, a door and window profile and a welding gun, and further comprises a positioning and grinding assembly and a dedusting and destressing assembly, welded door and window profiles do not need to be carried to independent polishing equipment, polishing is directly completed through state switching of the pressing plate, the inter-process circulation time is shortened, and positioning deviation caused by secondary clamping of traditional equipment is avoided; the functions of aluminum scrap collection and weld joint stress release in the polishing process are integrated in the pressing plate, polishing-dust removal-stress relief three-in-one synchronous treatment is achieved, the residual stress elimination effect is maximized, deformation of doors and windows in later use is effectively avoided, vibration force is transmitted through the pressing plate, and damage to the doors and windows is avoided; in addition, the vibration time is synchronous with grinding, stress relaxation is promoted through the micro-plastic state during material grinding instead of forced vibration in the cold state, and the welding seam cracking risk is greatly reduced.

The invention provides an intelligent temperature control method and system for relieving stress of a glass annealing kiln. The method comprises the following steps: transmitting acoustic surface waves through a distributed sonic sensor to collect stress propagation data in glass, decoupling coupling characteristics of sound velocity and temperature, extracting a relaxation time constant, and generating a stress relaxation rate; performing time difference cross-correlation analysis to construct a stress propagation three-dimensional gradient field, establishing an incidence relation between the relaxation rate and the gradient field, and constructing a mapping strategy of the temperature set value and the relaxation rate according to the incidence relation; generating a dynamic temperature adjusting parameter and converting the dynamic temperature adjusting parameter into a heater power control signal; and dynamically adjusting a stress data feature extraction rule to match a real-time stress state according to the relevance between the gradient field update frequency and the temperature adjustment rate. According to the application, dynamic mutual optimization of the annealing stress elimination efficiency and the kiln temperature setting precision is realized, the glass residual stress is reduced, and the hidden danger of plate explosion is eliminated.

The invention relates to the technical field of spring stress relaxation life prediction, in particular to a stress relaxation life prediction method for a push rod spring and a computer readable storage medium, and the method comprises the following steps: S1, installing test equipment and a spring; s2, testing spring stress relaxation data and drawing a curve; s3, drawing a natural logarithm curve of the natural logarithm of the stress loss rate and the natural logarithm curve of the time, and fitting a regression equation; s4, drawing a relation curve of the relaxation coefficient and the temperature and fitting a regression equation; s5, calculating the relaxation coefficient of the test spring at the actual use temperature; s6, calculating the stress relaxation life of the test spring; according to the method, stress relaxation curves and stress loss rate logarithm and time logarithm curves at different experimental temperatures are obtained in a temperature acceleration mode, and a stress relaxation equation of the logarithm of the stress loss rate with respect to the temperature T and the time t is finally obtained, so that the working life of the spring at the actual working temperature is accurately predicted; and the experimental period is shortened while the prediction accuracy is relatively high.

The invention discloses a preparation method of a high-performance Cu-Be-Co alloy strip. The preparation method comprises the following steps: preparing raw materials according to alloy components and contents of 0.2-0.4 wt% of Be, 0.5-0.6 wt% of Co and the balance of Cu; the preparation method comprises the following steps: smelting an alloy ingot by adopting a vacuum induction electromagnetic suspension furnace; on the basis of traditional solid solution-deformation-aging, the content of Be and Co in the Cu-Be-Co alloy is controlled, and cold deformation treatment is added after aging. According to the method, the mechanical property of the Cu-Be-Co alloy is greatly enhanced while the high conductivity is guaranteed, the Cu-Be-Co alloy strip with excellent comprehensive performance is obtained, the tensile strength of the obtained alloy strip reaches 863 Mpa, the conductivity is about 49.9% IACS, and the stress relaxation resistance performance that the stress relaxation is smaller than 10% within 100 h at the room temperature is achieved. The method is relatively simple, easy to operate and low in cost, and can meet the performance requirements of the copper alloy for contact current carrying.

The invention relates to a method for optimizing tempering heat preservation time in the tempering process of a supporting roller forge piece based on a finite element model, belongs to the technical field of heat treatment of the supporting roller forge piece, and solves at least one of the problems of energy waste, equipment occupation, high product cost and the like caused by overlong tempering time of an existing method. According to the method, the tempering heat preservation time of the supporting roller is optimized by integrating changes of the temperature, the structures and the residual stress, and the reduction or stabilization time of the residual stress is judged according to stress relaxation curves of different structures and is not obtained through finite element simulation in the creep deformation process; according to the method for judging the stress relaxation degree under the conditions of different structures and loads, namely, the stress relaxation curve is normalized, and the method can be directly and repeatedly used for optimizing the tempering heat preservation time of the supporting rollers which are made of the same material and have different specifications and different process parameters.

The invention discloses a manganin current sampling on-line self-correction method and system of an intelligent fusion terminal. The method and system are applied to the intelligent fusion terminal comprising a manganin diverter assembly. The assembly comprises a working resistor connected in series in a main current loop and a reference resistor for monitoring, the working resistor and the reference resistor are thermally coupled, and the reference resistor does not bear working current during normal sampling. The method comprises the following steps: respectively measuring real-time resistance values of the two resistors in a silent working window period; calculating a current actually measured resistance value ratio; obtaining an ideal resistance value ratio of the two in a stress relaxation-free ideal state; obtaining a correction resistance value ratio variable quantity according to a difference value between an actual measurement ratio and an ideal ratio; and finally, calculating a correction coefficient and updating a sampling channel parameter so as to compensate resistance drift caused by long-term electric thermal stress and realize automatic correction of subsequent current sampling. According to the method, on-line and high-precision self-correction independent of an external reference is realized, and the problem of long-term stress relaxation of a manganese-copper material is effectively solved.

The invention discloses an injection molding method and an injection molding device for a vehicle-mounted electronic structural member, and the method comprises the following steps: applying an excitation light source to obtain a polarization emission spectrum of engineering plastic, and forming a quantum optical fingerprint spectrum; carrying out polarization analysis on the spectral characteristic peak, and calculating a dichroic ratio to obtain molecular orientation three-dimensional distribution data; applying a laser pulse to acquire a coherent Raman scattering signal and a harmonic generation signal to obtain nonlinear optical response data; analyzing a molecular chain rearrangement characteristic and a stress relaxation characteristic based on the data to obtain kinetic parameters; and analyzing a molecular orientation evolution rule according to the kinetic parameters to obtain structure evolution prediction data. According to the technical scheme, the molecular orientation state of the engineering plastic can be monitored in real time in the injection molding process, and accurate characterization and prediction of the dynamic arrangement behavior of molecular chain segments are achieved through a method combining quantum spectrum analysis and nonlinear optical response characterization. And a scientific basis is provided for optimizing injection molding process parameters and controlling residual stress distribution in a product.

The invention discloses a copper-nickel-silicon alloy strip and a preparation method and application thereof.The copper-nickel-silicon alloy strip comprises, by mass, 1.8 wt%-2.2 wt% of Ni, 0.4 wt%-0.6 wt% of Si, 0.04 wt%-0.12 wt% of Mg, 0.1 wt%-0.2 wt% of Cr, 0.01 wt%-0.03 wt% of P, the mass content of Ni and the mass content of Zn + Sn meet the condition that Ni / (Zn + Sn) is larger than 1.4 and smaller than 2.5, and the balance copper and inevitable impurities; the copper-nickel-silicon alloy strip comprises a second phase, the second phase is mainly composed of Ni2Si and CrSi3, and the size of the second phase ranges from 0.08 micrometer to 0.50 micrometer. The alloy strip has high strength, excellent conductivity and bending performance and good stress relaxation resistance.

An optical component including: a substrate on which an optical element is mounted; a transparent sealing member disposed above the substrate and configured to seal the optical element; and a bonded portion in which a plurality of metal films are laminated, and which is configured to bond the transparent sealing member and the substrate. The bonded portion includes: one or more stress relaxation layers constituted by one or more metal films having a Young's modulus of less than or equal to 150 GPa, the one or more stress relaxation layers having a total thickness of greater than or equal to 1.2 μm; and a diffusion prevention layer disposed on each of both sides in a thickness direction of each of the one or more stress relaxation layers, and configured to prevent diffusion of metal constituting the stress relaxation layer.

The invention relates to aluminosilicate glass, a preparation method thereof and a glass product. The aluminosilicate glass is prepared from the following raw materials in percentage by mass: 58 percent to 63 percent of SiO2, 12 percent to 16 percent of Al2O3, 11 percent to 14.5 percent of Na2O, 3 percent to 6 percent of K2O, 2 percent to 5 percent of MgO, 1.4 percent to 3 percent of ZrO2 and 0.5 percent to 3.5 percent of B2O3. The preparation raw materials of the aluminosilicate glass comprise specific components with a specific proportioning relation, all the components are coordinated and matched to endow the aluminosilicate glass with good stress relaxation resistance and mechanical properties, and the service life of fused salt can be prolonged.

The composite terminal comprises a terminal body and a fixing sleeve, the terminal body comprises a welding part, a connecting part and a plugging part, the center of the plugging part is provided with a plugging hole, the center of the fixing sleeve is provided with a mounting through hole penetrating through the front end and the rear end of the fixing sleeve, and the plugging part is inserted into the mounting through hole to be welded and fixed to the fixing sleeve. The mounting through hole is communicated with the inserting hole, and the connecting part and the welding part are arranged on the outer side of the fixing sleeve. The composite terminal is simple in structure and rapid to install, a riveting wire part on the terminal body is omitted, a welding structure is adopted, the appearance of the terminal is simplified, the overall size of the terminal is reduced, a welding connection mode is adopted, the problem of mechanical stress relaxation is avoided, the vibration resistance and impact resistance are higher, and the service life of the terminal is prolonged. Stable transmission of electric signals is facilitated, and poor contact is avoided.

Glass-based articles comprise stress profiles providing improved drop performance. A glass-based substrate comprises: a glass transition temperature (Tg), a liquid fragility index (m), and fictive temperature (Tf), wherein Tg is less than or equal to 650° C., a value of Tf minus Tg is greater than or equal to −30° C., and m is greater than or equal to 25. A stress relaxation rate is greater than or equal to 10%, or 20% or more. The articles can comprise a lithium-based aluminosilicate composition and a fracture toughness that is greater than or equal to 0.75 MPa*m0.5. The stress profiles comprise: a spike region extending from the first surface to a knee; and a tail region extending from the knee to a center of the glass-based article, the tail region comprising: a negative curvature region wherein a second derivative of stress as a function of depth is negative; a depth of compression (DOC) that is greater than or equal to 0.22 t, and a parabolic region originating at the DOC and extending to the center of the glass-based article.

The invention provides a steel aging process numerical simulation method and system.The method comprises the steps that an initial constitutive model of creep fatigue of a to-be-tested steel material is built, and material parameters of the initial constitutive model comprise isotropic hardening parameters, follow-up hardening parameters and viscous stress parameters; the method comprises the following steps: performing a creep fatigue interaction experiment on a to-be-tested steel material at a preset temperature to obtain experimental data under the conditions of preset loading time, constant strain rate and constant strain amplitude, including a cumulative inelastic strain curve, a tensile curve and a stress relaxation curve; constructing a mechanical behavior model of the to-be-tested steel material according to the material parameters, and performing fitting by utilizing an accumulated inelastic strain curve, a tensile curve and a stress relaxation curve to obtain a target constitutive model; and utilizing the target constitutive model to perform aging numerical simulation on the to-be-tested steel material to obtain a change curve of stress along with time. And the aging process of the steel is simulated based on experimental data and a creep fatigue mechanism, so that the accuracy of aging evaluation and life prediction of the steel is improved.

The invention discloses a method and a system for determining a critical inelastic strain rate in a creep-fatigue damage process, and relates to the technical field of life prediction of high-temperature equipment, and the method comprises the following steps: obtaining a plurality of high-temperature equipment materials; based on the same temperature working condition, respectively carrying out creep, fatigue and creep-fatigue interaction tests on the high-temperature equipment material to obtain a creep test result, a fatigue test result and a creep-fatigue interaction test result; establishing a stress relaxation formula according to a creep test result; according to a fatigue test result, establishing a failure inelastic strain energy density fitting equation; establishing a net tensile hysteresis energy fatigue damage equation according to a creep-fatigue interaction test result; and determining the creep-fatigue life of the high-temperature equipment material based on a stress relaxation formula, a failure inelastic strain energy density fitting equation and a net tensile hysteresis energy fatigue damage equation according to a linear cumulative damage rule. According to the method, the creep-fatigue life of the high-temperature equipment material can be predicted more accurately.

The invention relates to the technical field of material performance test devices, in particular to a low-temperature tensile test device for an insulating material. The problems that an existing low-temperature stretching tool is poor in clamping and fixing effect on an insulating material in the nuclear fusion field, a sample is prone to torsion sliding in a test, stress relaxation is generated, and adaptability is insufficient are mainly solved. According to the technical scheme, the testing device comprises a clamp, a loading controller, a loading rod, a tensile sample, a force sensor, a supporting device, a testing machine reaction frame and a low-temperature environment box; the clamp comprises an upper clamp and a lower clamp; the low-temperature environment box is arranged outside the testing machine reaction frame, and the supporting device is installed outside the low-temperature environment box. According to the test device, stable positive pressure is applied to a sample, torsion sliding and stress relaxation are prevented, it is ensured that the stretching position of the sampled sample is stable and free of errors, the test failure rate is reduced, the qualification rate is increased, the clamp structures are the same, the pressing blocks are detachable, and universality and efficiency are improved.

The present application relates to the technical field of liquid rocket engine nozzle, and discloses a manufacturing method of an extension section of a large-scale liquid rocket second-stage engine nozzle, which is characterized in that the extension section is divided into n cylinder sections according to the size of the plate and the elongation rate of the plate, and each cylinder section is divided into m melon pieces to be prepared by means of tailor welding; the number n of the cylinder sections ensures that the number of the girth welds of the extension section is the least, and the welding of the girth welds is maximally avoided; the cylinder sections of the extension section are obtained by stress relaxation heat correction treatment of preformed cylinder sections, and the uncontrollable welding deformation problem is overcome. The present application solves the problem that the uncontrollable deformation caused by the springback of the sheet metal forming in the block welding leads to the difficulty in guaranteeing the profile tolerance of the inner surface of the nozzle extension section, improves the welding quality, reduces the rejection rate and production cost of the finished product, improves the production efficiency, has a wide application prospect, and any large-diameter thin-walled product can be processed according to the method of the present application.