26 results about "Ultimate load" patented technology

The invention discloses a deep foundation bearing capacity characteristic value calculation method and system based on data fusion. The method comprises the steps that data collection is completed through a deep load test, and a load settlement curve and a settlement time logarithmic curve are formed; generating a smooth curve; identifying a slope mutation point of the curve by adopting a first-order derivative mutation method, wherein a load corresponding to the mutation point is a proportional limit load; if the slope abrupt change point is not recognized, the curve is set as a slowly changing curve; extracting the slope and the slope change rate of the curve under each level of load, and completing the judgment and correction of the limit load by fusing the multi-dimensional data of the two curves and combining preset thresholds including the settlement amount and the settlement stabilization time; and further calculating the bearing capacity characteristic value of the deep foundation by combining the numerical relationship between the ultimate load and the proportional limit load.

The invention discloses a shield butt joint section curtain grouting additional load determination method, and relates to the technical field of geotechnical engineering grouting, and the method comprises the steps: carrying out the preprocessing of obtained grouting measurement data, obtaining an envelope point set, and carrying out the fitting optimization based on an envelope line function model, and obtaining an optimized envelope line function; calculating an ultimate load, attenuating the ultimate load to a preset engineering allowable threshold value to obtain an ultimate load acting distance, and determining boundary conditions through an envelope line intercept analysis method; and correcting the limit load according to a preset grouting load safety coefficient to obtain a corrected limit load, and performing inversion correction in combination with the grouting measurement data to obtain a final limit load and a final boundary condition. According to the method, the significant action range and the most unfavorable load condition of the grouting load are determined by capturing the spatial distribution and evolution law of the additional soil pressure field caused by grouting, and accurate load boundary conditions are provided for model analysis or finite element calculation.

The invention relates to the technical field of metal structure stability finite element analysis, in particular to a stability limit load calculation method based on a dichotomy and a computer program product, and the method comprises the steps: carrying out the structural modeling of a target structural part, completing the finite element pretreatment, applying an initial load to a modeled structure, obtaining an initial maximum Mises stress value of the structure, and calculating the stability limit load of the target structural part. According to the elastic field linear superposition principle and the stability upper limit principle, the initial load range [Flower, Fupper] of the stability limit load is calculated, then the load range is iteratively updated by adopting a dichotomy method until the convergence condition is met, the final stability limit load is obtained, the total calculation frequency is reduced by 40%-60%, and the final stability limit load is obtained. Meanwhile, full-process automation from load setting to result judgment is achieved, and the requirement for manual intervention is remarkably reduced.

The invention discloses a method and a system for evaluating the shear strength of a floating type wind power blade sandwich material. The method comprises the following steps: drawing a three-dimensional geometric shape of a blade; creating a blade finite element model according to a blade structure layering design drawing; inputting the limit load borne by the floating type wind power blade under the wind wave flow coupling effect, and simulating and calculating the out-of-plane shear stress of the sandwich material; the reduction coefficient of the shear strength of the sandwich material is determined by referring to blade design standards and considering influence factors on blade structure safety in design, manufacturing and testing processes, and the shear strength safety coefficient of the floating type wind power blade sandwich material is calculated. The system comprises a blade three-dimensional modeling module, a blade finite element modeling module, a sandwich material shear stress simulation module, a shear strength safety coefficient calculation module and an evaluation module. The method can be used for conservatively and efficiently evaluating the shear strength safety coefficient of the sandwich material of the floating type offshore wind power blade, and help is provided for the early-stage structure design stage of the floating type offshore wind power blade.

The invention belongs to the technical field of aircraft structural strength analysis, and particularly relates to a metal material stress plasticity correction method. The method comprises the steps that firstly, material parameters of the aircraft metal material structure are obtained; step 2, adopting a linear finite element static strength analysis method to obtain stress distribution of the aircraft metal material structure under the action of a limit load, and if the stress meets a preset condition, entering step 3; 3, according to the material parameters, the Ramberg-Osgood nonlinear hardening index during tensile failure is corrected, and the corrected nonlinear hardening index is obtained; and 4, constructing a stress equation, and substituting the nonlinear hardening index into the stress equation to obtain the real stress of the aircraft metal material structure after plastic correction. According to the method, the metal material stress of the aircraft metal material structure can be conveniently and quickly subjected to plastic correction.

This invention proposes a safety assessment method for delaminated composite materials based on the principle of damage non-propagation, belonging to the fields of composite material delaminated damage modeling and composite structure safety assessment. The method includes: constructing ultimate load envelopes that meet the damage non-propagation requirement under different damage sizes; for readily available binary observation data in practical engineering, i.e., whether damage propagates under specific damage sizes and load conditions, connecting discrete observations with a continuous parameter space through a latent variable model; using the Probit link function to map the predicted difference between the load and the ultimate load into a damage propagation probability; and constructing a likelihood model using a Bernoulli likelihood function; and optimizing the ultimate load envelope within a Bayesian framework. This invention can effectively support safety assessment and maintenance decisions for composite material structures in aerospace and other fields.

The invention discloses an aerospace equipment structure limit load inversion method based on historical maintenance data, and belongs to the related technical field of digital twinning. The method comprises the following steps: firstly, counting historical maintenance data of aerospace equipment, extracting and fitting the number of cycles of a target structure from service to damage, and determining the statistical life of the target structure; secondly, establishing a finite element model according to the actual loading condition of the target structure, and applying a load to obtain a stress field and a strain field of the target structure; thirdly, a fatigue prediction life calculation model based on the stress field and the strain field is established, and the fatigue prediction life is obtained. And finally, carrying out parameter optimization by taking the load as an optimization variable and taking an absolute value of a difference value between the minimum fatigue prediction life and the statistical life as an optimization target to obtain a limit load inversion result. According to the method, the most matched limit load amplitude is iteratively optimized by fully utilizing historical maintenance data and utilizing an optimization method, and powerful support can be provided for further operation maintenance, optimization design and the like of the structure.

The invention relates to an analysis and calculation method for a blade root connection structure of a wind driven generator, and the method comprises the steps: constructing a finite element model for coupling a blade shell unit and a blade root entity unit, and defining the material attributes of all parts; and a coupling connection relation between the blade shell unit and the blade root entity unit is set to simulate a real force transmission path. Then, target pre-tightening force is applied to the connecting bolts and locked, and distributed working loads are applied to the blade shell units at different angles in the pre-tightening state, so that the bending moment of the end of the blade root is larger than the limit load at the angle. And solving and calculating the loaded model, extracting stress data for connecting the bolt and the bolt sleeve, and performing strength and fatigue analysis on the bolt and the bolt sleeve based on the data. According to the method, the accuracy of stress calculation of the blade root connecting structure and the model precision are remarkably improved by introducing the geometric characteristics, the rigidity characteristics and the distributed load transmission path of the real blade, so that more reliable guidance is provided for design of the wind power blade root and the connecting structure.

The invention provides a method and a device for acquiring an equivalent load of an aircraft structure under a complex load. The method comprises the following steps: S1, acquiring a finite element analysis model and a boundary condition of the aircraft structure; s2, solving the finite element analysis model according to aerodynamic loads and conditions of all the load working conditions of the aircraft structure to obtain analysis results under limit loads corresponding to all the load working conditions; s3, according to the analysis results under the limit loads corresponding to all the load working conditions, obtaining safety margins corresponding to all the load working conditions; and S4, performing load equivalent analysis on the aerodynamic load of the load working condition corresponding to the minimum safety margin to obtain final concentrated loads and loading points of the final concentrated loads, and performing load equivalence based on a finite element analysis method so as to conveniently, quickly and accurately calculate the static test input load of the aircraft structure.

The invention discloses a blade shimmy bending moment limit load reduction method based on an impeller azimuth angle, which comprises the following steps: S1.1, acquiring the azimuth angle of a blade on an impeller rotating plane; s1.2, judging whether the fan is in a converter load shedding working condition or not; s1.3, judging whether the azimuth angle of a blade in advance of nine o'clock from the clockwise direction is smaller than a set azimuth angle or not at the load shedding moment, if so, performing synchronous control on the three blades by taking the maximum blade angle as a reference, and if not, entering the next step; s1.4, paddle opening or paddle closing control is conducted on the blades, and paddle opening is stopped after the paddle opening amplitude of the blades reaches a set threshold value; s1.5, after the blades reach nine o'clock, the blades are collected at a third set speed; and S1.6, judging whether the three blades respectively finish one paddle opening action or not, if so, performing synchronous control on the three blades of the fan by taking the maximum paddle angle as a reference, and if not, returning to the step S1.4. On the premise that the operation power of the wind driven generator does not need to be reduced, the shimmy bending moment limit load of each section of the blade can be effectively reduced.

The invention relates to the field of engineering machinery, and discloses a training method of a contact stress prediction model and a limit load prediction method and device.The training method comprises the steps that geometric parameters of an arm support, contact parameters of the arm support and a sliding block, multiple sets of arm support working condition data and multiple sets of measurement contact stress corresponding to the multiple sets of arm support working condition data respectively are obtained; constructing a contact stress prediction model according to the geometric parameters and the contact parameters of the boom; according to the contact stress prediction model and the multiple sets of arm support working condition data, simulating and calculating multiple sets of simulation contact stress corresponding to the multiple sets of arm support working condition data; and training the contact stress prediction model by using the plurality of groups of simulation contact stresses serving as the data set and the plurality of groups of measurement contact stresses serving as the verification set so as to continuously correct contact parameters, and stopping training until a preset condition is met. According to the method, the contact stress of the arm support and the sliding block can be accurately predicted by utilizing the trained contact stress prediction model, so that the limit load of the arm support can be more accurately designed.

The present invention discloses a method and system for designing the ultimate load of a mounting node, an electronic device, and a storage medium. The method for designing the ultimate load of a mounting node of the present invention first uses the test results of a whole-machine dropout containment test to correct a finite element model, thereby improving the calculation precision and accuracy of the finite element model. Then, the worst conditions are set in the corrected engine finite element model to calculate and obtain the design value of the ultimate load of the mounting node. The calculation simulation state is closer to the ultimate state of the full-ring blade loss load, and can be as close to the actual ultimate load as possible, thereby accurately determining the ultimate load of the mounting node of a civilian engine.

The present invention belongs to the field of aviation engines, relates to a static test design technology for aft-bearing casings, and provides a high-temperature static test design method and system for aft-bearing casings, the method comprising: determining the load analysis conditions and assessment locations of the aft-bearing casings within the engine envelope, the load analysis conditions comprising the ultimate load analysis conditions and the limiting load analysis conditions; determining the external loads under the load analysis conditions; constructing a static test piece for the aft-bearing casings; equivalencing the force loads in the external loads and the basic loads, respectively constructing the temperature fields for the ultimate load analysis conditions and the limiting load analysis conditions; allocating equivalent loads, first conducting a limiting load test, and then conducting an ultimate load test. The method of the present invention can meet the assessment requirements for static tests of aft-bearing casings, and more comprehensively guarantee the safety and reliability of aft-bearing casings in high-temperature environments.

The application discloses a spaceflight equipment structure limit load inversion method based on historical maintenance data and belongs to the technical field of digital twinning. First, historical maintenance data of spaceflight equipment is counted, the cycle number experienced by a target structure from service to damage is extracted and fitted, and the statistical life of the target structure is determined. Second, a finite element model is established according to the actual load condition of the target structure, and a stress field and a strain field of the target structure are obtained by applying a load. Third, a fatigue prediction life calculation model based on the stress field and the strain field is established, and the fatigue prediction life is obtained. Finally, the load is taken as an optimization variable, the absolute value of the difference between the fatigue prediction life and the statistical life is taken as an optimization target, parameter optimization is carried out, and the limit load inversion result is obtained. The application can provide strong support for further operation and maintenance and optimized design of the structure by fully utilizing historical maintenance data and iteratively optimizing the most matched limit load amplitude by using an optimization method.

The present invention discloses a method for determining the ultimate load after patch repair of a composite laminate, comprising the following steps: establishing a finite element model of an open-hole composite laminate; establishing a constitutive model for composite material damage; establishing a constitutive model for the composite adhesive layer; based on the ABAQUS-UMAT finite element user dynamic subroutine module, using FORTRAN language to write a user-defined subroutine to implement the proposed constitutive model for damage, and solving for stress, strain and damage; performing calculations on the finite element model to predict the ultimate load after patch repair of the composite laminate. The present invention uses the ABAQUS-UMAT user-defined subroutine to numerically implement the established three-dimensional constitutive model for damage, which simultaneously considers the effects of shear nonlinearity and degradation of material properties caused by damage accumulation, and can accurately predict the ultimate load after patch repair of the composite laminate.

The invention discloses a double-sliding-surface slope sliding mass multi-parameter acquisition method considering parameter degradation, and belongs to the technical field of slope stability analysis. The method comprises the following steps: dividing a double-slip-surface slope slip mass considering parameter degradation into two parts by a hypothetical interface; basic parameters, considering parameter degradation, of the sliding mass of the double-sliding-surface slope are prepared; carrying out stress analysis on the sliding mass of the double-sliding-surface slope, and establishing a sliding block acting force equation; a limit load equivalent equation is established by combining stress analysis and according to the first sliding block area and the second sliding block area; a sliding block acting force equation and a limit load equivalent equation are combined, and a double-sliding-surface slope sliding mass multi-parameter calculation model considering parameter degradation is established; and solving the multi-parameter calculation model of the sliding mass of the double-sliding-surface slope considering parameter degradation. The method is suitable for calculation of the ultimate load and the stability coefficient of the double-sliding-surface slope considering parameter degradation, and has the characteristics of clear concept, high calculation precision and simplicity and convenience in engineering application.

This invention discloses a method for analyzing the ultimate load of arch block instability in an inverted arch stilling basin. Using structural mechanics methods, a mechanical model of arch block instability is established, dividing the instability process into three stages: lifting of the middle arch block, sliding of the two side arch blocks, and warping of the two side arch blocks. Considering engineering safety and reasonable computational complexity, the model is simplified, and a simplified structural mechanics analysis method that facilitates manual calculation is proposed. This method can calculate the ultimate load of arch block instability corresponding to different anchoring forces in an inverted arch stilling basin, providing a reliable theoretical basis for the structural design of inverted arch stilling basins and possessing significant engineering application value.

The invention relates to a quick evaluation method and system for a wind resistance limit load probability average value of a structure, and the method comprises the following steps: S1, carrying out a wind tunnel test on the structure or obtaining a wind load time history of each point on the surface of the structure by adopting a wind tunnel test result in a database, building a finite element model through finite element numerical analysis software, and carrying out the elastic time history calculation, determining each key position of the structure and a corresponding response time history; s2, extracting the most unfavorable response of each key position, and respectively solving the most unfavorable wind load mode corresponding to each most unfavorable response by adopting an LRC method; s3, based on a stability increment elastic-plastic analysis theory, judging the stability of the structure by adopting an energy method, and solving a wind-resistant ultimate bearing capacity average value of the structure; the problems that the speed of solving the wind-resistant ultimate bearing capacity of the structure through a traditional structure elastic-plastic calculation method is low, and the accuracy of solving the wind-resistant ultimate bearing capacity of the structure is affected due to the fact that a traditional static stability method cannot reflect incomplete correlation and randomness of a real wind load on the structure are solved are solved.

The present invention proposes a safety assessment method, system, equipment and medium for a wind turbine test bench foundation. The assessment method obtains the inherent parameters of the test bench foundation and the extreme operating condition parameters, operating condition parameters and seismic condition parameters throughout its entire life cycle, and uses a pre-constructed finite element model to simulate the stress conditions of the test bench foundation during operation, thereby obtaining the ultimate load and fatigue load of the test bench foundation. Based on the inherent parameters, extreme operating condition parameters, operating condition parameters, seismic condition parameters, ultimate load and fatigue load, the test bench foundation is subjected to ultimate strength verification and fatigue strength verification, thereby achieving an accurate assessment of the design safety of the test bench foundation.

The invention relates to the technical field of aero-engines, and discloses an aero-engine static pressure-bearing part pressure containment test design method, which comprises the following steps: under a limited pressure load, determining that a first pressure containment margin is greater than a first set value; under the ultimate pressure load, it is determined that the second pressure containing margin is larger than a second set value; under the limited load, determining a first equivalent load of the pressure containment test of the static pressure-bearing part on the basis of ensuring that the yield strength margins of the static pressure-bearing part in the test state and the working state are equivalent; and under the limit load, determining a second equivalent load of the pressure containment test of the static pressure-bearing part on the basis of ensuring that the limit strength margins of the static pressure-bearing part in the test state and the working state are equivalent. By limiting the first pressure containing margin and the second pressure containing margin, the machine body damage and casualty risks caused by static pressure bearing piece damage are reduced; by introducing the first equivalent load and the second equivalent load, it is ensured that the static pressure-bearing part is tested in place.

The application discloses a method and device for establishing a shear wall shear bearing capacity prediction model, which comprises the following steps: performing a pushover test on a shear wall test piece, recording actual pushover test phenomena and obtaining the displacement of the shear wall test piece under corresponding loads, and drawing a first lateral force-displacement curve; determining actual typical characteristic loads of the shear wall based on the actual pushover test phenomena and / or the first lateral force-displacement curve, wherein the actual typical characteristic loads comprise an actual cracking load, an actual yielding load and an actual ultimate load; establishing a finite element model corresponding to the shear wall test piece; expanding the finite element model by using preset shear wall parameters to generate an expanded finite element model; performing simulation analysis on the shear wall test piece by using the expanded finite element model, and respectively establishing a cracking load prediction model, a yielding load prediction model and an ultimate load prediction model based on simulation analysis results and the actual typical characteristic loads.

The invention provides an aircraft cabin structure strength design method and system based on a limit load method, and the method comprises the steps: S1, building an aircraft cabin structure finite element model according to the constitutive relation of an aircraft cabin structure material; s2, applying boundary conditions in the finite element model to perform finite element simulation analysis; s3, calculating the limit load of the cabin structure according to the analysis result; and S4, based on the limit load and the safety coefficient, calculating to obtain the residual strength coefficient of the cabin structure. According to the method, accurate determination of the limit load and the residual strength coefficient of the aircraft cabin structure can be realized, an important theoretical guidance effect on optimal design of the cabin structure is achieved, the utilization rate of materials in the design process of the aircraft cabin structure is greatly improved, the lightweight design requirement of the aircraft cabin structure can be met, and the method has important engineering value.

The invention relates to a method for designing a ship model sailing in waves. The method comprises the following steps of: 1, determining a scale ratio of the ship model according to a test scene; secondly, the midship of the ship model is a ultimate bearing capacity cabin section, and the two sides of the ultimate bearing capacity cabin section are connected with the ship models at the two ends through transition sections; thirdly, measuring beams are installed on the ship models at the two ends; fourthly, a driving and steering assembly is installed on the ship model; fifthly, a laser displacement sensor is installed on the measuring beam, and a strain gauge is pasted on the ultimate bearing capacity cabin section; sixthly, the weight and the gravity center of the ship model are adjusted through the ballast blocks. By adding a hull beam ultimate bearing capacity testing technology, a testing technology capable of simultaneously measuring wave bending moment, ultimate bearing capacity, hull motion parameters and the like is formed, and technical support is provided for mastering a ship structure failure mode in an ultimate wave environment, obtaining the ultimate bearing capacity and the like; meanwhile, a foundation is laid for ship structure safety evaluation and structure optimization design.

The present invention discloses a method for calculating the ultimate load of a metal-lined composite cylindrical shell. The cylindrical shell includes an outer fiber composite layer and an inner metal layer. First, a geometric equation is established to divide the fiber composite layer into a number of composite unit layers; the metal layer is cut into a number of metal unit layers with the same thickness; the relationship between stress and strain in each composite unit layer and metal unit layer is established respectively; the in-plane stiffness matrix, coupling stiffness matrix and bending stiffness matrix of the cylindrical shell are calculated based on the equilibrium relationship; a linear buckling load model is established; the linear buckling load model is corrected considering the damage of the material after being subjected to force; and the ultimate load is calculated using the corrected model. By considering the material damage model, the ultimate load of the metal-lined composite cylindrical shell is obtained through quantitative analysis, the crushing load of this type of multi-layer cylindrical shell is reliably predicted, and the compressive failure assessment of the multi-layer composite cylindrical shell under external pressure is improved, thereby making the structural design safer and more reliable.

The application discloses an experimental device for simulating fracture failure of anti-slide piles and a use method thereof, belongs to the technical field of geotechnical engineering reinforcement, adopts modular design, and comprises a pile top module, at least one pile middle module, a pile bottom module and a plurality of variable cross-section ultimate load limiting modules; the pile middle module is an upper and lower plate structure hinged by a flat hinge, the modules are slidably connected through convex and concave guide rails, the ultimate load limiting modules are inserted into aligned wedge-shaped holes, fracture occurs at the middle weak part when the ultimate load is reached, and shear failure and bending failure of the anti-slide pile can be simulated respectively. The fracture load can be accurately controlled by adjusting the thickness of the limiting module, the application has the advantages of simple structure, convenient disassembly and assembly, reusability, high test precision and suitability for research on the fracture failure mechanism of the anti-slide pile under different working conditions.

This disclosure provides a method for controlling a hoisting mechanism used to lift an aircraft in near space, comprising: setting the ultimate load that the aircraft must meet under target operating conditions based on risk factors that may cause abnormalities in the aircraft; establishing a finite element model to characterize the aircraft to be lifted and the hoisting mechanism used to lift the aircraft, and using the ultimate load as the excitation input of the finite element model to calculate the mechanical simulation under the target operating conditions to obtain displacement simulation data of the aircraft under the target operating conditions; manufacturing a solid scale-down model including the aircraft and the hoisting mechanism; adjusting the hoisting rope structure with the structural strength of the solid scale-down model of the aircraft as the limit, so that the solid scale-down model of the aircraft can switch between multiple target operating conditions, and constructing the allowable force envelope of each hoisting rope of the hoisting rope structure; controlling the hoisting mechanism carrying the aircraft based on the allowable force envelope of each hoisting rope, so that the aircraft can switch between multiple target operating conditions, from the lifting stage to the release stage.