22 results about "Plane stress" patented technology

The invention discloses a stress distribution evaluation method and device of a superconducting magnet, electronic equipment and a storage medium, and belongs to the field of stress distribution calculation.The method comprises the steps that a finite element model of the superconducting magnet is obtained, winding simulation and cooling simulation are sequentially carried out, winding stress distribution and thermal stress distribution are obtained through calculation, and a finite element model of the superconducting magnet is obtained; superposing the two to construct a pre-stress field; performing electromagnetic field modeling on the model to obtain electromagnetic force distribution; further carrying out multi-field coupling stress analysis, and identifying a key stress plane with most concentrated stress; and finally, constructing a two-dimensional plane stress model based on the plane, and inputting winding and thermal stress as pre-stress and electromagnetic force as external load into the two-dimensional model so as to efficiently calculate final stress distribution of the superconducting magnet. Therefore, by implementing the method, the problems of unreliable stress calculation and low solving efficiency in the prior art can be solved.

The invention relates to the technical field of mechanical property testing of metal materials, and provides an unsteady-state in-situ high-temperature forming property testing device and method. A punch constant strain rate loading model is arranged in the device, the punch moving speed is adjusted in real time to realize punch constant strain rate loading, and the rheological behavior of a constant strain rate sensitive material in a complex stress state is accurately tested; a rapid cooling system is arranged, so that accurate simulation of complex unsteady-state forming processes such as actual hot stamping and warm forming is realized, and the unsteady-state in-situ high-temperature forming performance of the material is obtained; in combination with a DIC dynamic strain measurement technology, a strain field and deformation force are collected in real time in a plate high-temperature plane stress bulging test, and local necking strain and main strain and secondary strain change paths are determined. According to the method, the reliability of researching macroscopic rheological behaviors such as strain field distribution, flow behavior, hardening mechanism, forming limit and fracture limit of the plate in a complex stress state can be remarkably improved.

The invention belongs to the technical field of aircraft thin-wall structure design, and particularly relates to a method for correcting a quadrilateral shell unit in aircraft thin-wall structure finite element analysis, which comprises the following steps of: 1, establishing a unit coordinate system for the quadrilateral shell unit; step 2, under the unit coordinate system, establishing an equilibrium equation of a plane stress unit related to in-plane deformation, and calculating a rigidity matrix of the plane stress unit; step 3, under the unit coordinate system, establishing a balance equation of a bending plate unit related to out-of-plane deformation, and calculating a rigidity matrix of the bending plate unit; 4, applying an in-plane rotation penalty term on the rotational stiffness of the quadrilateral shell unit, and calculating the influence of the in-plane rotation penalty term on the strain energy function of the quadrilateral shell unit under the unit coordinate system to obtain an in-plane rotation stiffness matrix; 5, calculating a stiffness matrix of the quadrilateral shell unit under the unit coordinate system; and step 6, coordinate transformation is carried out to obtain a stiffness matrix of the quadrilateral shell unit under the overall coordinate system.

The invention relates to the technical field of steel rail damage, and provides a near-field dynamics simulation method for steel rail head multi-crack competitive propagation, which comprises the following steps: establishing a near-field dynamics plane stress model of a steel rail head and dispersing the near-field dynamics plane stress model into particles; defining a particle interaction domain by adopting a double-vision-field key-based near-field dynamics method; setting boundary conditions and introducing a plurality of initial cracks on the surface of the rail head; applying a load to simulate a wheel-rail rolling contact process; simulating a multi-crack competitive expansion behavior based on the fracture state and fatigue life evolution of the key; and the interaction between the cracks is quantified by calculating the opening displacement and the sliding displacement of the crack tip. According to the method, the limitation that only a single crack can be simulated in the prior art is overcome, competitive expansion high-precision simulation of multiple cracks under the dynamic load is realized, the experiment cost is remarkably reduced, and a scientific basis is provided for steel rail fatigue damage assessment and maintenance decision making.

The application discloses a test system and a test method for simulating the stress wave action of a columnar charge blast hole, and relates to the technical field of rock dynamics and blasting engineering. The test system comprises a dynamic loading system, an incidence system, a stress wave conversion body and a sample model. The dynamic loading system generates a plane stress wave. The plane stress wave is conducted to the stress wave conversion body through the incidence system. The stress wave conversion body is attached to the sample model half-cylindrical channel through a semi-cylindrical pressure-arc surface, and the plane stress wave is converted into a cylindrical stress wave acting on the sample. The application generates controllable plane stress waves through the dynamic loading system, and the plane stress waves are shaped and directed through the incidence system, so that the waveform is stable, the energy loss is low, and the input conditions are consistent. The stress wave conversion body converts the plane stress wave into a cylindrical stress wave attached to the columnar blast hole through a plane-arc structure, highly simulates the radial diffusion characteristics of the real blasting stress wave, and realizes the simulation of the columnar charge blast hole blasting stress wave loading in the laboratory.

This invention relates to a method for testing the fracture toughness of anisotropic eccentrically loaded single-sided notched tensile specimens, comprising: S1, establishing a two-dimensional plane stress model of anisotropic material ESET specimens; S2, mesh generation; S3, calculating displacement, strain, and stress field to obtain the stress intensity factor K and compliance C under different initial crack lengths and anisotropic material parameters; S4, establishing crack length calculation formulas and stress intensity factor calculation formulas based on compliance under different eccentric loading rates, initial crack lengths, and anisotropic material parameters. This invention allows for rapid and accurate measurement of crack length simply by measuring the deformation of the material under external force; it reliably extends the application range of standardized eccentrically loaded single-sided notched tensile specimens from traditional isotropic metals to modern advanced materials such as composite materials, additive manufacturing alloys, and rolled plates, while ensuring the calculation accuracy under anisotropic conditions.

The present application relates to the field of gyroscopic load calculation, and discloses a gyroscopic load calculation method and system based on 2D finite elements, which comprises the following steps: establishing a ring element model for the axisymmetric structure in an aero-engine rotor, and using integration and isoparametric transformation to calculate the gyroscopic load expression of all ring elements in the ring element model; establishing a plane stress element model for the non-axisymmetric structure in the aero-engine rotor, and calculating the gyroscopic load expression of all plane stress elements according to the element thickness of the plane stress elements in the plane stress element model; generating a system total load equation according to the gyroscopic load expression of the ring elements and the gyroscopic load expression of the plane stress elements, and solving the system total load equation to obtain the gyroscopic load of the aero-engine rotor; and the system comprises a data acquisition module, a modeling module and a calculation module. The present application can improve the accuracy of the calculation results, simplify the calculation process, improve the calculation efficiency, and save a large amount of manpower.

The invention provides a method and a system for carrying out steel plate plane stress ultrasonic detection by utilizing multiple holes, belongs to the technical field of ultrasonic detection, and aims to solve the technical problems of how to accurately measure the wave velocity of ultrasonic waves in a steel plate and how to obtain stress-strain parameters of the steel plate by utilizing the wave velocity. Comprising the following steps: establishing a rectangular coordinate system I, an original point O, a transverse axis X1 and a longitudinal axis Y1, located on the plane of a measured steel plate; a second rectangular coordinate system located on the plane of the measured steel plate is established, the second rectangular coordinate system is obtained by rotating the first rectangular coordinate system around an original point O by theta, and the original point is O, the transverse axis is X2, and the longitudinal axis is Y2; acquiring the propagation speed of the ultrasonic wave in each axial direction; obtaining positive strain in each axial direction based on the first equation and the propagation speed; obtaining the positive stress in each axial direction based on the second equation and the positive strain; and obtaining the shear stress of each coordinate system based on the third equation and the normal stress. The method has the technical effects of improving the wave velocity detection accuracy and further improving the stress strain detection accuracy.

This invention discloses an experimental system and method for simulating the stress wave effect of a cylindrical charge blast hole, relating to the fields of rock dynamics and blasting engineering. The system includes a dynamic loading system, an incident system, a stress wave converter, and a sample model. The dynamic loading system generates a plane stress wave, which is transmitted through the incident system to the stress wave converter. The converter, through a semi-cylindrical pressure arc surface, conforms to the semi-cylindrical channel of the sample model, converting the plane stress wave into a cylindrical stress wave that acts on the sample. This invention generates a controllable plane stress wave through the dynamic loading system, which is shaped and directionally transmitted by the incident system, ensuring waveform stability, low energy loss, and consistent input conditions. The stress wave converter, with its flat-arc structure, converts the plane stress wave into a cylindrical stress wave conforming to the cylindrical blast hole, highly simulating the radial diffusion characteristics of real blasting stress waves. This allows for the simulation of stress wave loading during a cylindrical charge blast hole blast in a mine within the laboratory.

The present invention discloses a finite element analysis method, apparatus, equipment, and storage medium for stiffening plate units, relating to the field of finite element analysis and calculation. The method includes establishing a local coordinate system oxyz of the plate unit with the mid-surface of the stiffening plate unit as a reference; calculating the plane equivalent thickness and bending equivalent thickness of the stiffening plate unit in the x-axis and y-axis directions; calculating the plane stress unit elastic modulus and the bending plate unit elastic modulus of the stiffening plate unit in the x-axis and y-axis directions to construct a plane stress unit elastic matrix and a bending plate unit elastic matrix; and constructing a plane stress unit stiffness matrix and a bending plate unit stiffness matrix based on the plane stress unit elastic matrix and the bending plate unit elastic matrix to calculate the internal forces and stresses of the plane stress unit and the bending plate unit. The present application can accurately and efficiently perform finite element analysis of stiffening plate units, meeting engineering requirements.

The invention discloses a drill hole plane stress measurement method based on hole circumference relative displacement change. The method comprises the following steps: step 1, drilling a to-be-measured drill hole at a preset position to a preset measurement depth; 2, a mounting hole is concentrically drilled in the bottom of the drill hole, and a plurality of deformation meters used for measuring the relative displacement of the hole periphery are mounted on the hole periphery of the mounting hole; and step 3, the sleeve core is adopted to remove the to-be-measured drill hole, the relative displacement change of the periphery of the deformation meter mounting hole is obtained through the deformation meter in the removing process, and the plane stress state of the rock around the to-be-measured drill hole is obtained through relative displacement calculation. The method is simple in measurement and high in anti-interference capability, and the stress state of the drill hole can be calculated only by testing the relative displacement of three points around the hole.

The invention discloses a plate shell unit construction method for eliminating a shear self-locking effect, and relates to the technical field of ship engineering, and the method comprises the steps: constructing a thick plate bending unit under a local coordinate system, and correcting the stiffness characteristic of the thick plate unit through employing a hypothesis shear strain method, thereby effectively avoiding the numerical ill-conditioned condition when the shear strain tends to zero. A plane stress unit under a local coordinate system is constructed, and a non-coordinated mode is introduced to improve the deformation capability of the plane stress unit. The unit stiffness matrixes of a thick plate bending unit and a non-coordinated plane stress unit are integrated, the synergistic effect of a hypothetical shear strain field and a non-coordinated displacement field is achieved, and a unified plate shell unit capable of effectively eliminating the shear self-locking effect is efficiently constructed. According to the method, the requirement for modeling of the plate shell unit in ship structure simulation can be met, and the progress of ship structure finite element simulation is promoted.

The application belongs to the technical field of aircraft thin-walled structure design, and particularly relates to a correction method of quadrilateral shell element in finite element analysis of aircraft thin-walled structure, which comprises the following steps: step one, establishing an element coordinate system for the quadrilateral shell element; step two, establishing a balance equation of a plane stress element related to in-plane deformation under the element coordinate system, and calculating a plane stress element stiffness matrix; step three, establishing a balance equation of a bending plate element related to out-of-plane deformation under the element coordinate system, and calculating a bending plate element stiffness matrix; step four, applying an in-plane rotation penalty term to the rotational stiffness of the quadrilateral shell element, calculating the influence of the in-plane rotation penalty term on the strain energy function of the quadrilateral shell element under the element coordinate system, and obtaining an in-plane rotation stiffness matrix; step five, calculating the stiffness matrix of the quadrilateral shell element under the element coordinate system; and step six, performing coordinate transformation to obtain the stiffness matrix of the quadrilateral shell element under the overall coordinate system.

The invention discloses a composite material fatigue layering expansion rate estimation method considering a fiber bridging mechanism, and belongs to the technical field of composite material fatigue layering prediction. The method aims at the problem that prediction of the fatigue layering expansion rate of the composite material cannot be separated from fatigue test data support. Comprising the steps that a fiber bridging mechanism is considered, a fiber bridging factor is set, and a nonlinear continuous curve related to fracture toughness and layering length is obtained based on a static test; obtaining a tangential traction force and a normal traction force by combining the tangential displacement and the normal displacement; combining the surface internal stress resultant force, the surface internal bending moment and the surface internal shear stress resultant force of the upper sub-beam and the lower sub-beam to obtain the total strain energy of the composite laminated plate; a control equation set is obtained by establishing a laminated plate balance equation; solving to obtain an upper sub-beam fatigue load theoretical value, an upper sub-beam displacement theoretical value and a layering length theoretical value; and calculating a fatigue layering expansion rate, and fitting to obtain a fitting curve for estimating the expansion rate. The method is used for estimating the fatigue layering expansion rate.

The invention relates to an in-plane internal stress driven fatigue crack area expansion rate model, the specific model is a formula (1), the in-plane internal stress driven fatigue crack expansion rate can be determined by using the model, and the crack expansion area and form are obtained; the model construction method comprises the following steps: establishing a global digital twinning model, introducing an initial crack and a welding residual stress field at typical details, loading by utilizing a fatigue load model, simulating fatigue crack propagation by adopting a digital twinning method, and constructing the model. Counting fatigue crack area increments corresponding to different loading times in the crack propagation process and I-type fatigue crack strain energy release rates, obtaining an in-plane internal stress driven fatigue crack area propagation rate / -delta GI curve by using a difference algorithm, and establishing an in-plane internal stress driven fatigue crack area propagation rate model by using a least square method in a fitting manner; the model can represent the surface internal stress driven crack three-dimensional expansion behavior, and can provide a basis for detail surface internal stress driven fatigue mechanism research and damage evaluation.

The invention discloses a stiffening rib plate unit finite element analysis method, device and equipment and a storage medium, and relates to the field of finite element analysis computation.The method comprises the steps that a plate unit local coordinate system oxyz is established with the plate middle face of a stiffening rib plate unit as the benchmark; the plane equivalent thickness and the bending equivalent thickness of the stiffening rib plate units in the x-axis direction and the y-axis direction are obtained through calculation; calculating the elastic modulus of the plane stress unit and the elastic modulus of the bending plate unit of the stiffening rib plate unit in the x-axis direction and the y-axis direction so as to construct a plane stress unit elastic matrix and a bending plate unit elastic matrix; according to the plane stress unit elastic matrix and the bending plate unit elastic matrix, a plane stress unit stiffness matrix and a bending plate unit stiffness matrix are constructed, and internal force and stress calculation of the plane stress unit and the bending plate unit is achieved. According to the method, finite element analysis of the stiffening rib plate unit can be accurately and efficiently achieved, and engineering requirements are met.

An ultrasonic measurement method for plane stress on the basis of a multi-wafer air-coupled transducer relates to the technical field of ultrasonic testing. The method solves problems that a traditional measurement method for plane stress generally computes the plane stress by changing at least 3 different measurement directions and obtaining information such as an acoustic time difference in the 3 measurement directions by using a pair of contact ultrasonic transducers, which is too complicated in operation, and a coupling agent can influence measurement accuracy of the plane stress. The method includes: emitting, by an excitation signal transmission end, an ultrasonic wave passing a wafer of the multi-wafer air-coupled transducer to a member to be measured; receiving, by an excitation signal reception end, an echo returned from the member to be measured through a corresponding wafer of the multi-wafer air-coupled transducer; obtaining an acoustic time difference of lamb waves through data processing according to the ultrasonic wave and the echo; and obtaining first principal stress, second principal stress and an included angle between the first principal stress and a fiber direction of an orthotropic composite material according to the acoustic time difference of the lamb waves. The method is suitable for the field of plane stress testing.

An air-coupled ultrasonic plane stress detection method for a composite material based on dual-modal sound-time ratios of a Lamb wave includes: S1: assembling a detection device; S2: based on the detection device and the dual-modal sound-time ratios of the Lamb wave in S1, using unidirectionally loaded stress to obtain different stress coefficient relations; S3: based on the stress coefficient relations in S2, solving stress coefficients; S4: based on the stress coefficients in S3, acquiring three sound-time ratios; S5: based on the sound-time ratios in S4, describing a stress state of a detection point; and S6: repeating S4 and S5 till completing detection and scanning. The method improves the accuracy of stress coefficient calibration and air-coupled ultrasonic stress representation of a composite material panel greatly.

The application provides a method and system for steel plate plane stress ultrasonic detection by using a plurality of holes, belongs to the technical field of ultrasonic detection, and is used for solving the technical problems of how to accurately measure the wave speed of ultrasonic waves in a steel plate and how to obtain the stress and strain parameters of the steel plate by using the wave speed. The method comprises the following steps: establishing a rectangular coordinate system I located on the plane of the measured steel plate, wherein the origin is O, the horizontal axis is X1, and the vertical axis is Y1; establishing a rectangular coordinate system II located on the plane of the measured steel plate, wherein the rectangular coordinate system II is obtained by rotating the rectangular coordinate system I around the origin O by an angle of θ, the origin is O, the horizontal axis is X2, and the vertical axis is Y2; obtaining the propagation speed of ultrasonic waves in each axial direction; obtaining normal strain in each axial direction based on a first equation and the propagation speed; obtaining normal stress in each axial direction based on a second equation and the normal strain; and obtaining shear stress of each coordinate system based on a third equation and the normal stress. The application has the technical effect of improving the accuracy of wave speed detection and then improving the accuracy of stress and strain detection.

The present invention provides a method for measuring rock tensile strain and its mechanical parameters using a circular ring deformation method, relating to the technical field of rock mechanics testing. The method comprises: installing a deformation sensor in a circular ring specimen and ensuring close contact between the sensor and the inner hole of the specimen; radially loading the circular ring specimen using a testing machine and monitoring the deformation of the inner hole diameter in a direction parallel to the load during the compression of the specimen, thereby obtaining a curve showing the relationship between the load and the vertical deformation of the circular ring specimen of rock or rock-like materials within the hole; and obtaining the tensile strain value, ultimate tensile fracture strain, elastic modulus, and tensile strength of the rock material based on the curve. This method effectively utilizes the advantages of circular ring specimen testing, overcomes the influence of large errors in the plane stress state and strain point measurement data in the measurement of tensile mechanical parameters of rock or rock-like materials, improves measurement accuracy, and provides a basis for further analysis of parameters such as the tensile strength of the material.

The invention provides a parallel inclined rock stratum deep-buried support tunnel mechanical response analysis method and system, and the method comprises the steps: obtaining mechanical parameters of a parallel inclined rock stratum deep-buried support tunnel, and constructing a plane stress mechanical model according to the mechanical parameters; constructing corresponding conformal mapping functions for all independent boundaries in the plane stress mechanical model; deducing an undetermined complex coefficient vector based on the plane stress mechanical model and the conformal mapping function; selecting a plurality of calculation boundary points on the independent boundary by using a point matching method, and constructing a corresponding condition constraint equation according to the boundary condition of the independent boundary where each calculation boundary point is located; and assembling all the condition constraint equations to obtain an integral linear equation set, and then resolving the undetermined complex coefficient vector by using the integral linear equation set to obtain a mechanical property solution. The problems that in the prior art, the analysis difficulty of the mechanical response of the deep-buried supporting tunnel in the parallel inclined rock stratum is high, and the accuracy of the analysis result is difficult to control are solved.

This invention provides a method and apparatus for calculating the stress of a steel plate by measuring the strain of the steel plate. The method is based on the strain data collected by a triaxial strain rosette attached to the steel plate, and calculates the stress in the two stages before and after the steel plate yields. By calculating the stress of the steel plate at a specific location, the entire process of stress development in the steel plate under plane stress is analyzed, and the influence of various parameters on the mechanical properties of the steel plate can be analyzed.