26 results about "Total strain" patented technology

The invention provides a tunnel deformation monitoring system and method based on a distributed optical fiber sensing technology, and relates to the technical field of tunnel monitoring. A spiral winding type optical fiber is arranged in the longitudinal axis direction of the surface of a tunnel lining, a transverse optical fiber is arranged on a key section, and the data acquisition frequency is set to be 1Hz. Dividing the optical fiber into a plurality of data acquisition points at equal intervals, obtaining the real-time temperature and Brillouin frequency shift change of each point, measuring the temperature and strain sensitivity coefficient, and calculating the total strain; calculating long-term temperature strain compensation based on the long-term temperature component, generating an instantaneous temperature difference through the real-time temperature and the long-term temperature component, further calculating instantaneous temperature strain compensation, subtracting the two kinds of strain compensation from the total strain to obtain stress strain, and evaluating the deformation level of the tunnel based on the stress strain. And the accuracy of evaluation is judged through clustering analysis.

The invention provides a rock-soil body stability analysis method and system based on strain energy density, and relates to the technical field of rock-soil body stability analys.The rock-soil body stability analysis method comprises the steps that rock-soil body parameters of field investigation and indoor tests are obtained; combining the rock-soil body parameters, the generalized Hooke law and the Mohr-Coulomb yield criterion to obtain a strain tensor expression, and performing stress tensor calculation to obtain an elastic stress tensor, a strain tensor and a plastic strain tensor of the rock-soil body; respectively carrying out integral calculation to obtain the total strain energy density increment of the rock-soil body in different stress states; and performing stability analysis based on the total strain energy density increment of the rock-soil body in different stress states to obtain a stability abnormal area of the rock-soil body. According to the method, the elasticity and plastic deformation characteristics of the rock-soil body are comprehensively considered, and the accuracy of stability evaluation is improved.

The invention discloses a method for predicting high-temperature and complex stress of a ceramic-based composite material based on strain control damage evolution, and belongs to the technical field of stress prediction of ceramic-based composite materials. The method comprises the following steps: determining material high-temperature performance degradation conditions according to temperature; the total strain (mechanical strain and thermal strain) of the material is calculated, and then based on a three-dimensional failure criterion of strain control, six damage initial criterion equations including stretching and compression in the warp direction, the weft direction and the out-of-plane direction are constructed; establishing an evolution model of damage coefficients by introducing a coupling mechanism of damage factors in different directions; combining a multi-linear constitutive relation of the ceramic matrix composite material to construct a rigidity degradation matrix, and realizing rigidity adjustment of the failure unit; and finally deducing a stress-strain relation equation to complete stress prediction of the material under the conditions of high temperature and complex load. The prediction method provided by the invention can accurately predict the complex stress state of the ceramic matrix composite material under the combined action of the high temperature and the mechanical load.

The present invention relates to a stress intensity limit S t A failure probability assessment method is provided, comprising: obtaining creep rupture test data of specimens under different working conditions, including creep rupture life and creep strain-time curves; determining the standard error of the logarithmic creep rupture life; determining the average stress required for the total strain to reach 1%, the minimum stress at the onset of the third stage of creep, and the minimum stress causing creep rupture under each working condition, as the first criterion stress, the second criterion stress, and the third criterion stress, respectively; determining creep life models corresponding to the first, second, and third criterion stresses; determining creep life models considering safety factors corresponding to the first, second, and third criterion stresses; determining probability parameters corresponding to the first, second, and third criterion stresses based on the creep life model after introducing probability parameters and the creep life model considering safety factors for each criterion; and calculating the failure probabilities of the first, second, and third criterion stresses under different working conditions.

The present application relates to the technical field of bridge health monitoring and detection, and discloses a prefabricated assembled beam bridge longitudinal damage rapid diagnosis method, which comprises the following steps: collecting actual structure parameters of a bridge, establishing a bridge finite element calculation model for calculating a theoretical strain influence line; arranging strain measuring points at the longitudinal midspan of the two outer side beams and the middle beam of the prefabricated assembled beam, and performing a pseudo-static loading test; extracting the strain of the beam bridge strain measuring points, fitting and drawing a strain influence line; calculating the total strain meters of the two outer side beam strain measuring points; calculating the total strain meter change amplitude ΔS of the two outer side beam measuring points; establishing a ΔS column chart of the two in the same coordinate axis, and comparing with a longitudinal damage qualitative diagnosis graph system to obtain a qualitative diagnosis result. The prefabricated assembled beam bridge longitudinal damage rapid diagnosis method has the advantages of short diagnosis time, no interruption of traffic, improved economy, realization of rapid comprehensive diagnosis of the prefabricated assembled beam bridge longitudinal damage, and improved diagnosis accuracy.

The application provides a somatosensory method and system based on an intervertebral fusion cage with an optical fiber inside, and relates to the technical field of intervertebral fusion cages. The method comprises arranging four cascaded optical fiber units arranged in the same direction and in a quadrangular distribution inside four support crossbeams of the intervertebral fusion cage respectively. When the intervertebral fusion cage is pressed, the support crossbeam arranged above the bone window is elastically deformed, four fiber gratings generate corresponding strains, the total pressure received by the intervertebral fusion cage is calculated according to the total strain generated by the four fiber gratings; the moment Mx in the X direction received by the intervertebral fusion cage is calculated according to the strain difference generated by the left two fiber gratings and the right two fiber gratings; the moment My in the Y direction received by the intervertebral fusion cage is calculated according to the strain difference generated by the front two fiber gratings and the back two fiber gratings; the motion state of the lumbar vertebrae is judged through the total pressure, the moment Mx and the moment My, and then the intervertebral fusion condition is evaluated.

The invention discloses a strain simulation method and a board card, and relates to the technical field of computers, in the method, when strain simulation is carried out on the board card, the maximum tensile strain of each sub-region of a board card model is searched based on the tensile strain distribution of the last frame of multiple analysis steps, and a maximum tensile strain cloud picture is constructed based on the maximum tensile strain; and based on the compressive strain distribution of the last frame of the plurality of analysis steps, searching for the minimum compressive strain of each sub-region of the board card model, and based on the minimum compressive strain, constructing a minimum compressive strain cloud picture. Compared with strain nephograms obtained by superposing a plurality of analysis steps in some technologies, the total strain nephogram obtained by superposing the maximum tensile strain nephogram and the minimum compressive strain nephogram achieves similar effects. And under the condition of similar effects, only two cloud pictures need to be superposed, so that the superposition times of the strain cloud pictures can be greatly reduced, and the simulation efficiency can be further improved.

The invention relates to a parachute canopy fabric numerical simulation method and a computer readable storage medium. The method comprises the steps that material parameters and historical states are initialized and read; updating an accumulated total strain tensor based on the strain increment and calculating a strain rate tensor; the principal direction modulus is evolved according to the accumulated total strain tensor, the material stiffness matrix is updated, and then the pure elastic stress increment is calculated; viscous damping stress is calculated in combination with the strain rate and the stiffness matrix, and a trial stress tensor is obtained after superposition and historical stress; performing wrinkle correction on the trial stress according to the strain state in the main direction, eliminating the stress in the compression direction and reducing the corresponding shear stress; calculating a dynamic strength threshold value by adopting a logarithmic strengthening model based on the strain rate and judging failure; and finally storing the updated state and outputting the stress tensor. A computer program is stored on the readable storage medium, the method can be implemented when the program is executed, and high-fidelity numerical simulation of the mechanical behavior of the canopy fabric is achieved.

The application discloses a flexible three-dimensional slender structure shape sensing method based on an optical fiber strain sensor, and comprises the following steps: arranging a distributed optical fiber sensor on a to-be-measured slender structure; dividing the to-be-measured slender structure into a plurality of units, and each unit is provided with a plurality of sub-regions; introducing an absolute node coordinate method, and obtaining a total strain conversion matrix of each sub-region according to the coordinates of the position of the distributed optical fiber sensor; acquiring linear strain along the arrangement direction at the arrangement position of the distributed optical fiber sensor by using the distributed optical fiber sensor; constructing a correlation algorithm by using the total strain conversion matrix and the measured strain value, so that the coordinates and directions of each node between units can be obtained; and substituting the coordinates of each node into a finite element shape function to obtain the shape of the deformed slender structure. Compared with other existing shape sensing algorithms, the application can realize shape sensing of three-dimensional slender structures with different cross-sectional shapes on the basis of relatively freely designing the optical fiber arrangement scheme.

This invention provides a tunnel deformation monitoring system and method based on distributed optical fiber sensing technology, belonging to the field of tunnel monitoring technology. The invention involves arranging helically wound optical fibers along the longitudinal axis of the tunnel lining surface and arranging transverse optical fibers at key sections, setting the data acquisition frequency to 1Hz. The optical fibers are equidistantly divided into multiple data acquisition points to acquire real-time temperature and Brillouin frequency shift changes at each point, and to measure temperature and strain sensitivity coefficients to calculate the total strain. Long-term temperature strain compensation is calculated based on long-term temperature components, and instantaneous temperature difference is generated using real-time temperature and long-term temperature components to calculate instantaneous temperature strain compensation. These two strain compensations are subtracted from the total strain to obtain the stress-strain. The deformation level of the tunnel is assessed based on the stress-strain, and the accuracy of the assessment is determined through cluster analysis.

The invention discloses a coal and rock mass tension-shear deformation decoupling monitoring method, system and equipment based on a generalized equivalent geometric model and a medium, and relates to the field of coal mine rock mechanics monitoring, the method comprises the following steps: collecting a Brillouin frequency shift signal of each analysis unit to obtain the total optical fiber axial strain of each analysis unit; for any analysis unit, obtaining a real dislocation displacement vector to be determined according to the initial length and the deformation length; decomposing a real dislocation displacement vector to be determined into a projection component and equivalent shear displacement along the axial direction of the optical fiber; forming an equivalent right triangle model based on the initial length, the deformation length, the projection component along the axial direction of the optical fiber and the equivalent shear displacement; obtaining a tension-shear coupling equation based on the equivalent right triangle model; and based on the total axial strain of the optical fiber of the analysis unit, determining equivalent axial strain and equivalent shear displacement by adopting a tension-shear coupling equation. According to the method, accurate decoupling of the complex tension-shear deformation field of the coal and rock mass is realized.

The invention discloses a method and a system for processing strain data of upper concrete of an inverted-T-shaped cover beam bridge deck, and relates to a bridge technology. The method comprises the following steps: acquiring structural parameters of the inverted-T-shaped cover beam bridge deck; according to the structural parameters, calculating the strain generated by the temperature load on the upper concrete of the inverted T-shaped cover beam bridge deck; calculating the strain generated by the beam end rotation load on the upper concrete of the inverted T-shaped cover beam bridge deck; calculating concrete generated by the dead weight of the bridge deck on the upper part of the inverted T-shaped cover beam bridge deck; calculating the concrete generated by the vehicle load on the upper part of the inverted T-shaped cover beam bridge deck; from this, the total strain is calculated. The method aims at solving the problem that a traditional simply supported girder bridge deck continuity theory is based on a two-dimensional simplified model, continuous three-dimensional space stress characteristics of an inverted T-shaped bent cap bridge deck cannot be accurately reflected, and consequently the deviation between a strain calculation result and the reality is large, and the stress calculation precision is improved.

This invention belongs to the technical field of nuclear reactor engineering and structural reliability assessment, specifically relating to a method, program, equipment, and storage medium for predicting the fatigue life of lead-bismuth reactors for multi-morphological variable-scale core components. This invention constructs multi-morphological variable-scale structural components for the target core component, and experimentally collects temperature and total strain time-domain sequences. It extracts the effective mechanical strain of actual fatigue damage using thermoelasticity formulas, introduces the generalized Hooke's law, and transforms it into an equivalent uniaxial stress time-domain sequence. It uses the rainflow counting method to extract the cycle number for each set of operating conditions, and determines the allowable life of the target core component material under each operating condition based on the S-N fatigue characteristic curve of the target core component material. Finally, it introduces the Miner linear fatigue damage accumulation method to calculate the total cumulative damage, thereby predicting the fatigue life of the target core component.

The invention relates to a multi-material structure dimension reduction topological optimization design method considering interface tension and compression anisotropy. The method comprises the steps that in the first stage, a rigidity-oriented multi-material interface topological optimization method based on material field series expansion is adopted; in the second stage, topological optimization of interface tensile strain energy constraint is considered, the space gradient of a material field function is calculated through central difference, and then an interface region is positioned by using a gradient norm; processing the gradient norm diagram by adopting a pn norm smooth expansion operator; obtaining tension and compression strain energy based on strain tensor eigenvalue decomposition; an interface tensile strain energy constraint is constructed by limiting the ratio of the interface tensile strain energy to the total strain energy, and optimization is carried out based on interface tensile strain energy constraint function iteration; and a delay activation strategy is designed, and the opportunity that the first-stage optimization enters the second-stage optimization is controlled, so that the overall rigidity and the interface performance are effectively balanced, and the structure-interface collaborative optimization of'efficient calculation-precise boundary control-stable convergence-reliable performance 'is realized.

A strain amount measuring device 1 comprises: a total strain amount determining unit 11 that determines a distribution [Expression 1] of each component of a total strain amount during loading or after unloading of a material; and an elastic strain amount calculating unit 12 that calculates an eigen strain amount [Expression 2] after unloading of the material. The elastic strain amount calculating unit 12 subjects the total strain amount to an inverse Fourier transform [Expression 5] using a 6×6 matrix [Expression 4] defined by an elastic constant Cijkl and a wave number k [Expression 3], to thereby calculate an eigen strain amount, and then calculates an elastic strain amount [Expression 6].

The invention discloses a recombined bamboo structure failure judgment method based on strain energy density, which comprises the following steps: converting a constitutive equation of a recombined bamboo in a stress state into a plane stress equation, measuring strain data of the recombined bamboo through a stress sheet, obtaining stress data based on the plane stress equation, ignoring the influence of the size effect of the stress sheet, and judging the failure of the recombined bamboo structure. Strain energy density is calculated based on the stress data, total strain energy is further obtained, average strain energy density of the volume of the recombined bamboo unit body is determined based on the total strain energy, a relation curve between the slope of the average strain energy density and the load is obtained, and the failure state of the recombined bamboo is judged according to the relation curve. According to the method, by combining the relation curve between the average strain energy density slope and the load, the failure point of the structure is judged, the evolution characteristics of the stress process of the structure can be clearly represented, and the failure state of the structure can be accurately predicted.

The invention belongs to the technical field of fatigue failure, and relates to a method and a system for evaluating fatigue failure of a welding joint in a lead-bismuth environment. The method comprises the following steps: performing a fatigue test on a welding joint in a lead-bismuth environment to obtain fatigue life data under different total strain amplitudes and obtain a fatigue design curve, and clarifying the fatigue performance of each part in the environment; comparing the total strain amplitudes when the welded joint and the base metal have the same fatigue life to obtain a fatigue failure factor, and evaluating the fatigue reliability of the welded joint; a cyclic stress-strain constitutive model is constructed, fatigue failure factors are coupled, the reliability of the model is verified through a numerical model, the prediction precision of the model on the fatigue behavior of the welding component is improved, and a systematic method and data support are provided for fatigue design, life evaluation and reliability analysis of the welding component in a lead-bismuth environment.

The present invention relates to a method for predicting the low cycle fatigue life of metastable austenitic dual-phase steel, comprising: S1, calculating the elastic strain energy density ΔW through low cycle fatigue test data; e , plastic strain energy density ΔW' p , and calculate the total strain energy density ΔW' t and strain energy density ratio Q; S2, construct a low-cycle fatigue life prediction model for metastable austenitic dual-phase steel; S3, calculate the parameters of the low-cycle fatigue life prediction model for metastable austenitic dual-phase steel; S4, use the low-cycle fatigue life prediction model to predict fatigue life. The present invention takes into account the influence of martensite generated during cyclic loading of metastable austenitic dual-phase steel on fatigue crack propagation. From an energy perspective, the martensite generated during cyclic loading will affect both elastic strain energy and plastic strain energy. The present invention takes into account the strain ratio R and equivalent stress σ eq The impact on fatigue life, fatigue life prediction model prediction is more accurate.

This invention discloses a method for early warning of steel structure deformation under thermo-mechanical coupling, relating to the field of structural health monitoring technology. The method includes: acquiring real-time strain and temperature data of the steel structure monitoring area; identifying a pure thermal loading window based on the strain and temperature data and inverting the equivalent thermal strain coefficient; accumulating and integrating the equivalent thermal strain coefficient with the temperature change rate to obtain the thermal strain, and subtracting the thermal strain from the total strain to obtain the force-induced strain; calculating the force-induced strain accumulation rate, which is equal to the integral of the absolute value of the force-induced strain change rate within a preset integration window divided by the window duration; identifying the microplasticity initiation point based on the changing trend of the force-induced strain accumulation rate, using the force-induced strain accumulation rate corresponding to the microplasticity initiation point as the critical accumulation rate, and using the product of the critical accumulation rate and a preset safety factor as an adaptive early warning threshold; outputting a deformation early warning signal when the force-induced strain accumulation rate reaches the threshold. This invention achieves early warning of the risk of plastic deformation in steel structures.

The application discloses a kind of optimal construction sequence determination methods of large-span space truss structure.The method includes: establishing the numerical simulation model of large-span space truss structure, and it is divided into multiple structure blocks;Joint state space including lifting node and construction time sequence is constructed, and the total strain energy area obtained by numerical integration of total strain energy of large-span space truss structure in construction process to cumulative characteristic displacement is established as evaluation objective function;Global iterative solution is carried out in joint state space using preset optimization algorithm, and the optimal joint strategy that makes the total strain energy area minimum is output, to determine the initial optimal lifting point and the initial optimal construction sequence corresponding;Real-time acquisition of stress deformation data in actual construction to calculate actual total strain energy area, when deviating from theoretical benchmark reaches preset threshold, trigger optimization algorithm to dynamically correct construction sequence.The application breaks the traditional decision limit, realizes joint global optimization and dynamic digital twin closed-loop control in time and space dimensions, and improves construction safety.

The application belongs to the field of reliability test of aero-engine or gas turbine rotor components, and provides a pre-tightening force attenuation test method of end tooth connecting bolts under high temperature and high rotating speed, which comprises the following steps: coaxially installing a test piece on a driving shaft; selecting a strain gauge arrangement scheme, processing one or more mounting planes at a non-threaded matching position of a screw rod of the connecting bolt, and pasting high-temperature strain gauges according to the selected scheme; performing static warming calibration on the test piece provided with the high-temperature strain gauges, and establishing a calibration relationship between temperature and thermal output strain; performing a rotating test under a target rotating speed and a target test temperature, and synchronously collecting total strain; decoupling the total strain based on the calibration relationship to obtain mechanical strain, and calculating an attenuation amount of the connecting bolt. The application can realize accurate and dynamic monitoring of the pre-tightening force attenuation under real high temperature and high rotating speed conditions, and provides an effective technical means for reliability verification of an aero-engine rotor end tooth connecting structure.

The present application relates to the technical field of additive manufacturing, and discloses a sintering-based additive manufacturing hierarchical porous lattice pore and shrinkage prediction method, comprising: establishing a double-pore model to decompose the pore system of the lattice component into micro and macro relative densities; establishing a total strain rate equation to decompose the total strain rate of the lattice component into strain rate components; wherein the strain rate components are determined according to the densification rate of the micro relative density and the constitutive parameters; establishing a micro relative density evolution equation, and iteratively coupling the total strain rate equation and the micro relative density evolution equation to obtain the node displacement field and the micro relative density field, and determine the evolution of the macro relative density; and according to the micro relative density field and the evolution result of the macro relative density, the prediction result of the hierarchical pore and three-dimensional structure shrinkage deformation is obtained. The present application can be directly used for geometric pre-compensation of the additive manufacturing green body, and improves the manufacturing success rate and product precision of the lattice component.

The invention provides a simulation method for transverse isotropic aging characteristics of composite soft rock and related equipment, and solves the technical problem of long-term deformation prediction of a composite soft rock tunnel. The method comprises the following steps: decomposing total strain into elastic strain, plastic strain and viscous strain; constructing a transverse isotropic elastic model, a transverse isotropic plastic model and a transverse isotropic viscous model; obtaining an initial value of a transverse isotropic parameter; according to the initial value of the transverse isotropic parameter, the transverse isotropic elastic model, the transverse isotropic plastic model and the transverse isotropic viscous model, calculating the stress state of the rock influenced by anisotropy; calculating an included angle between a rock bedding surface and the maximum principal stress direction according to the stress state; and transverse isotropic elastic-plastic analysis and transverse isotropic creep analysis are executed based on the anisotropy influence stress state until a preset convergence criterion is reached, and a composite soft rock rheological transverse anisotropy simulation model is obtained.

The invention relates to the technical field of offshore piles, and discloses a method, a device, equipment, a medium and a product for analyzing the response of a pile foundation under a vertical load. The method comprises the following steps: acquiring parameter values of undrained shear strength and initial shear modulus of a soil layer of a target site and a static stress-total strain curve; determining a first incidence relation among the static stress, the plastic strain and the total strain in the soil layer of the target site; determining a third incidence relation between the static stress and the elastic strain according to a second incidence relation among the total strain, the elastic strain and the plastic strain and the first incidence relation; and determining a t-z model curve according to a fourth incidence relation between the static stress and the frictional resistance, a fifth incidence relation between the pile body settlement and the plastic strain and the third incidence relation between the pile body settlement and the elastic strain. And substituting into the finite element model to carry out response analysis on the pile foundation under the vertical load.

The invention belongs to the technical field of exploration, and provides a shale brittleness index calculation method, system, equipment and medium, and the method comprises the steps: collecting a shale sample, applying stress to construct a stress-strain curve, and obtaining data such as total strain, Young modulus and peak strain from the stress-strain curve; and determining normalized maximum and minimum boundary data of the strain, the Young modulus and the peak strain at the same time. And respectively calculating the plastic deformation of the shale in the compaction section and the crack growth section, the plastic deformation in the linear section and the shale fracture difficulty degree by using different data. The average value of the plastic deformation of the shale in the compaction section and the crack growth section, the plastic deformation of the shale in the linear section and the shale fracture difficulty degree is used as the shale brittleness index. The method can accurately evaluate the brittleness of the shale.

The present application relates to the technical field of material measurement, and in particular to a test method for obtaining stress-strain relationship of linear hardening elastic-plastic material, a storage medium and equipment. The test method for obtaining stress-strain relationship of linear hardening elastic-plastic material comprises the following steps: obtaining a test block or a component with smooth surface; obtaining a load-displacement h-load P curve of the test block surface or the component surface by using a micro-damage indentation test; establishing a load P-displacement h model according to the relationship between the total strain energy of the material of the test block or the component and the strain energy density, effective deformation domain volume; calibrating key parameters of the load P-displacement h model based on a finite element auxiliary test method; fitting the load-displacement h-load P curve and the load P-displacement h model to obtain the stress-strain relationship of the linear hardening elastic-plastic material. The present application tests the linear hardening elastic-plastic material by using the micro-damage indentation test, reduces the loss of the material and the service equipment, and thus achieves the purpose of high-throughput test.