37 results about "Shell theory" patented technology

The invention provides a method for determining distributed process parameters of a laser peening forming complex curved surface. The method comprises the following steps: establishing a function relationship between a deflection curved surface and an intrinsic moment based on plate shell mechanics, and establishing an optimization model based on partial differential equation constraint by takinga distributed intrinsic moment function as a design variable; according to a curved surface parameter equation or a curved surface coordinate of the workpiece, dispersing a target curved surface, selecting an appropriate optimization algorithm to solve an optimization model, and calculating a distributed natural moment; dividing into a plurality of isoparametric areas convenient for process operation according to the size of the distributed natural moment, and determining a laser peening forming scanning scheme in each area; and establishing a process database corresponding to process parameters and inherent moments through experiments, determining the experiment process parameters, and determining the optimal distributed process parameters in combination with the requirements of residualstress. The method for determining the complex curved surface forming technological parameters is established on the basis of the elastic plate shell theory, and high efficiency and precision are achieved.

The invention belongs to the field of coal mine filling mining rock layer control, and particularly relates to a filling mining overlying rock fault zone height determining method based on a plate and shell theory. The method comprises the following steps of firstly, judging the position of a hard rock layer; then, obtaining the critical load and the limit displacement of the hard rock layer; next, obtaining the free space height under the hard rock layer and the overlying load on the hard rock layer; and judging whether the fault zone develops or not by comparing the critical load with the overlying load on the hard rock layer and comparing the limit displacement with the free space height under the hard rock layer. Various basic parameters related in the method can be obtained after working face mining design completion by methods such as geological data and experiment tests. The method has the advantages that the theoretical and data basis can be provided for the overlying rock damage prevention and treatment measures adopted in the filling mining process; and the disaster due to filling mining working face overlying rock damage is reduced. The method provided by the invention has wide practicability on the analysis of the filling mining overlying rock activity rule.

The invention provides a correcting method for a layer-peeling-method residual stress measurement value based on the plate and shell theory. For increasing the measurement accuracy of the residual stress inside a material of the layer peeling method, based on the elastic mechanics and the plate and shell theory, a calculating method for releasing of the residual stress inside the material in the material removing process is deduced, and therefore the conversion relationship between surface residual stress peeled layer by layer and initial residual stress of a layer is established; under the condition that all kinds of surface residual stress after layer peeling are known, the initial residual stress of the layer can be reversely calculated and obtained.

The invention relates to a back penetration type measurement method for film-substrate cohesion performance in the measurement technical field. An ejector rod is adopted by the invention to penetrate the basement system of a part to be measured. Load is arranged on the lower end of the ejector rod. And the ejector rod is pushed to make a film deformed in a way of bending. The defection and the load of the film are respectively obtained by corresponding sensors when loaded in a static load form. The film-substrate cohesion of the part to be measured under static load is worked out through the plate shell theory. When load is added in a dynamic form, a relationship between the crack growth length and the cycle number, which is used for evaluating the fatigue performance of the film, is built up through measuring the radius of a film salient area and recording the cycle number. The invention solves the technical problems in present technology that the precast of the part to be measured is complex and the basement system is limited by silicon material. The invention can quantitatively measure the film-substrate cohesion performance, precisely determine the film-substrate cohesion and obtain the fatigue performance parameters of the film.

The invention discloses an ultrasonic non-intervention pressure detection method based on information fusion of a plurality of transition waveforms. According to the method, a critical refraction longitudinal wave, a first reflection longitudinal wave, a fourth reflection longitudinal wave and a fifth reflection longitudinal wave are selected as pressure detection waveforms; and the relation between a pressure in a container and an ultrasonic speed is derived by the use of an ultrasonic sound elasticity principle and a plate and shell theory, and then the measuring module of the relation between a time delay and the container pressure is established according to the relation between the ultrasonic speed and the time delay. Based on the idea of information fusion, a plurality of waveforms are used as detection waveforms, and under the condition that time delay measuring precision of a single ultrasonic wave is not high, the relatively high pressure detection precision can still be realized. According to the method, transmission time delays, including pressure information and temperature information, of each waveform serve as input variables of the measuring module, and there is no need to measure temperature parameters of a container wall, so that errors generated in the temperature measuring process is avoided. Verified by experiments, the method is relatively high in measuring precision.

The invention relates to a rapid complex plate and shell thickness optimization design method based on maximum displacement, and belongs to the field of rapid mechanical structure optimization design. According to a finite element theory and the theoretical relation among stress, load, displacement and a rigidity matrix in a plate and shell theory, an optimal plate and shell thickness calculation formula based on maximum displacement is deduced. As the influence of complex structural characteristics on structural performance cannot be ignored, the thickness of a complex plate and shell structure is difficultly calculated directly by the plate and shell theory. The method can be used for rapidly calculating the optimal solution of the complex plate and shell structure meeting corresponding critical maximum displacement requirements, and has the advantages of rapidness, small calculation amount, easiness in solution and the like.

The invention provides a bolt connection cylindrical shell structure dynamic characteristic calculation and analysis method, and belongs to the technical field of mechanical dynamics. The method comprises the following steps: establishing a cylindrical shell energy equation according to a plate-shell theory; establishing a load excitation equation according to the external load condition; establishing a bolt connection mechanical equation according to the bolt connection characteristics; solving bolt connection equivalent stiffness and equivalent damping according to first-order Fourier decomposition; accurately expressing different load characteristics through component force in each vibration displacement direction; obtaining a forced vibration differential equation of the bolt connection cylindrical shell structure through a Lagrange equation; and solving the dynamic characteristics of the bolted connection cylindrical shell structure by applying an incremental harmonic balance method. The method starts from the establishment of a bolted connection equivalent mechanical model, is applied to a cylindrical shell structure, achieves the solving of the vibration response according to the demands of different actual working conditions, simplifies the modeling and calculation process, is high in precision, is high in universality, and the like.

The invention relates to an ellipsoidal corrugated heat transmission sheet structure. Corrugation of a heat transmission sheet corrugated section consists of semi-ellipsoidal curved surfaces arrayed in a matrix manner; long axes of the semi-ellipsoidal curved surfaces are in the same direction as the long side of a heat transmission sheet; and middle axes of the semi-ellipsoidal curved surfaces are in the same direction as the broad side of the heat transmission sheet. The structure has the following advantages that: 1) the corrugation of the heat transmission sheet consists of the semi-ellipsoidal curved surfaces, and is provided with a larger heat transmission surface, so that a coefficient of heat transmission is increased; 2) the semi-ellipsoidal curved corrugation has higher strength and rigidity according to a shell theory, and does not deform easily; and 3) the structure is simple, is formed by one-time stamping; and the production cost is lowered. With the adoption of the structure, a heat transmission area is increased; the strength and the rigidity are improved; the flow channel resistance is reduced simultaneously; the new balance between the reduced flow resistance and a good heat transmission effect is achieved; and a significant progress is obtained.

The invention relates to a rapid complex shell thickness optimization design method based on maximum equivalent stress and belongs to the field of rapid optimization design of mechanical structures. According to the method disclosed by the invention, the optimal shell thickness calculation formula based on the maximum equivalent stress is deduced according to a theoretical relation among the stress, load, displacement and stiffness matrix in a finite element theory and a plate shell theory. Aiming at the complex shell structure, since the influence of the complex structure characteristic on the structural performance cannot be neglected, the thickness of the complex shell is difficult to be directly calculated by the plate shell theory. The method is capable of rapidly calculating the optimal solution under the condition that the corresponding maximum equivalent stress is met, and has the advantages of rapidness, small calculation amount, simplicity in solution and the like.

The invention discloses a blade detection method based on blade load analysis, and belongs to the technical field of wind driven generators. The method comprises the following steps: 1, monitoring and acquiring vibration signal data of a fan blade through a sensor for detecting vibration of the fan blade, and converting the vibration signal data into modal data; 2, constructing the modal data in the step 1 into a model through a finite element analysis (FEA) tool, and adding an orthotropic material constitutive relation and geometrical characteristics of a plate-shell theory on the model to obtain a cantilever beam model comprising parameters of a fan blade load F and a stiffness matrix K; 3, conducting static load analysis on the cantilever beam model obtained in the step 2, and calculating the deformation u of the cantilever beam model, wherein u = {F}/[K], {F} represents comprehensive force borne by the blade and comprises self gravity and wind power, and [K] represents the stiffness matrix; and 4, conducting dynamic load analysis on the cantilever beam model obtained in the step 2, applying full constraint to the root of the blade, conducting modal analysis on the single blade through finite element software, obtaining the first six-order vibration mode and the inherent frequency of the blade, and obtaining the vibration mode node position of the blade fault position in the blade bending direction, so that the defect position and the defect type of the to-be-detected blade are obtained.

The invention discloses a thin-walled cylinder mirror image cutting modeling method based on a shell theory. The method comprises the following steps that 1, a thin-walled cylinder mirror image cutting process system is simplified; a turning tool is equivalent to a rigid body, a boring rod and a thin-walled cylinder are equivalent to a flexible body, and the thin-walled cylinder of a machined object can be seen as a cylindrical shell; a workpiece is to be fixed, centripetal force and Coriolis force generated when the part rotates are ignored, and the machining process is simplified into forcedvibration of the static cylindrical shell under excitation of rotating force; 2, a forced vibration equation of the rotary thin-walled cylinder is established by applying a shell theory; 3, a boringrod vibration kinetic equation is established; 4, a dynamic cutting force model of the cutting process system is established; and step 5, a mirror image cutting kinetic model of the thin-walled cylinder is established, and calculating and solving are carried out by utilizing a Runge-Kutta method.

The invention provides a follow-up air floatation supporting thin-walled cylinder mirror image cutting modeling method based on the shell theory. The method comprises the following steps that S1, systematic dynamics modeling is conducted on a workpiece; S2, systematic dynamics modeling is conducted on a boring rod; s3, modeling is carried out on the dynamic cutting force of the cutting process system; S4, modeling is carried out on the cutting process system without support; and S5, modeling is carried out on the cutting process system with follow-up air floatation support. According to the follow-up air floatation supporting thin-walled cylinder mirror image cutting modeling method based on the shell theory, complex modal shape and workpiece rotation of a thin-walled cylinder in the circumferential direction and the axial direction are considered, and turning/boring machining of the thin-walled cylinder is converted into vibration response of a cylindrical shell under the rotating load; a follow-up air flotation supporting device commonly used in production is added, the number of supports and the positions of supporting points can be adjusted according to the process, and the vibration response of the thin-walled cylinder part under the mirror image machining process can be simulated truly.

The invention discloses a method for calculating orthotropic material parameters of a motor, and belongs to the field of motors. The method aims to solve the problem that an existing method is high in calculation difficulty during motor modal analysis. According to the method for calculating the orthotropic material parameters of the motor, the orthotropic analysis model with the shell theory as the core is utilized, the low-order radial inherent frequency easy to measure and the corresponding order of the low-order radial inherent frequency serve as input conditions, and the orthotropic material parameters of the motor can be simply and rapidly calculated. Meanwhile, a motor stator core lamination structure is considered, and errors caused by neglecting reduction of axial rigidity are avoided; the low-order radial inherent frequency and the corresponding order thereof are used as input conditions which are simple, accurate and easy to obtain.

The invention discloses a method for calculating the natural frequency of natural vibration of a marine pipeline. The method comprises the following specific steps: measuring the radius R, the lengthL, the wall thickness h and the density [rho] of the marine pipeline; determining the Young modulus E and the Poisson's ratio [mu] of the marine pipeline material; measuring the density rhof of seawater; and calculating the free vibration inherent frequency of the marine pipeline through an inherent frequency calculation formula when the fluid-solid coupling effect is considered. Based on the plate-shell theory, the influence of the fluid-solid coupling effect of the fluid and the shell structure on free vibration of the shell is considered, the free vibration phenomenon of the marine pipelineis integrally analyzed, and a more reasonable, simpler and more convenient inherent frequency calculation method is provided.