697 results about "Finite element calculations" patented technology

The invention discloses an ANSYS-based crosslinking polyethylene insulated cable temperature field finite element calculation method. The method successively comprises the following steps: firstly, taking a crosslinking polyethylene insulated cable as a research object and performing parametric geometric modeling based on a simulation software ANSYS, secondly, applying current excitation to the crosslinking polyethylene insulated cable to perform magnetic field analysis, applying voltage excitation to the crosslinking polyethylene insulated cable to perform electric field analysis then, and simultaneously loading joule heat loss, eddy-current loss and medium loss obtained from the magnetic field analysis and the electric field analysis to the crosslinking polyethylene insulated cable to be taken as heat sources, perform temperature field analysis and perform calculation of a crosslinking polyethylene insulated cable temperature field. The method has great flexibility and adaptability of solving for complex regional and border problems, can more accurately calculate the temperature of a crosslinking polyethylene insulated cable conductor, and then can explore the potential of cable current carrying capability; and the method can save cable investment, and also can improve the cable utilization rate and cable operating level.

The invention provides a design method for a die molded surface and a panel die to solve the technical problem that in the prior art, the precompensation precision of the die molded surface is low. The design method for the die molded surface includes the following steps that firstly, the elastic deformation amount of the die under punching force is calculated; secondly, extracting and coupling of a grid node point cloud are calculated based on a die deformation finite element; and thirdly, the exquisite die surface is generated based on finite element calculation. The design method for the die molded surface is used for designing the panel die, and the precompensation precision of the die molded surface is improved.

The invention relates to a beam bridge state evaluation method, which comprises the following steps of: 1) installing an FBG (fiber bragg grating) sensor on a beam bridge to be detected; 2) carrying out a quasi static load experiment on the beam bridge to be detected to obtain a control point deflection value; 3) comparing the control point deflection value obtained in the step 2 with a control point deflection value obtained by a finite element calculation model to obtain a beam bridge correction coefficient h; and 4) judging the working situation of the bridge structure according to the beam bridge correction coefficient h calculated in the step 3. The elevation method disclosed by the invention is convenient and practical; light load is used for replacing heavy load to lower the experiment expenditure; traffic interruption time is reduced; quasi static load or dynamic load is used for replacing static load; the analytical algorithm of the load experiment result can be directly obtained from a quasi static load experiment result so as to greatly lower the later-stage analysis difficulty of the quasi static load experiment data; and a quick load experiment method is used for replacing the traditional load experiment method.

The invention provides a large ship superstructure hoisting method which is implemented through the following steps: 1, calculating the whole weight and gravity center of the superstructure, configuring a hoisting point according to gantry crane equipment parameters and calculating the length and included angle of steel wire ropes; 2, designing a hoisting ring according the hoisting point and the whole weight; 3, carrying out reinforcement arrangement on the superstructure according to the hoisting point and stress distribution thereof; 4, establishing finite element modeling, carrying out whole strength check through finite element strength calculation, establishing a whole reinforced superstructure finite element model comprising the hoisting ring in MSC.Patran simulation software according to a structural drawing, and checking the whole and local strength through calculation; 5, reinforcing and modifying the steps 2 and 3 according to finite element calculation and strength check results, and rechecking; and 6, hoisting. Compared with the prior art, the method provided by the invention has the advantages of fully meeting technical indexes, obviously shortening the dock period at the same time, greatly relieving the defects of a ship integral assembly field and steadily improving the annual ship building quantity.

The invention relates to a modeling method of a motor in electromagnetic field-flow field-temperature field coupling calculation. The method comprises the following steps that (1) a finite element calculation model of the motor is established, and an electromagnetic field value is calculated; a rotor calculation domain is set into a multi-component fluid calculation domain, and a model calculation domain of air, a rotor conductor and a rotor iron core is established; (3) the value is calculated in the corresponding model calculation domain, and the velocity of movement is worked out; (4) a result which is worked out from the calculation of the electromagnetic field value and the calculation domain of each part of the multi-component fluid serves as load and is loaded into a temperature field to solve and calculate, and a temperature result is worked out. The method is adopted to set the rotor calculation domain into multi-component fluid; in such a manner, after a rotor part which is originally slid is equivalent into liquid, the rotor part can be processed and solved quickly and conveniently through a fluid control equation, so that not only is the heat loss of all parts in the motor calculated comprehensively and precisely, but also the calculation time and calculation complexity can be greatly reduced.

The invention provides a bridge fast load experimental test method comprising the following steps that a bridge finite element calculation model is established; a displacement measuring point is arranged at the key part of a test span; automobiles are slowly driven along the bridge deck, and the displacement influence line of the bridge is acquired; the actually measured curve of the bridge displacement influence line is drawn; the actually measured displacement value of high credibility is selected according to the actual result of the displacement influence test data; a multi-condition loading model is established according to the selected actually measured displacement value and the vehicle load corresponding position so as to perform finite element analysis and calculation; a displacement residual error expression is established, and a target function is formed to perform finite element model correction; and the deflection and the strain under the load test condition are calculated by adopting the corrected finite element model, the corrected model calculation value acts as the actually measured value and the uncorrected model calculation value acts as the theoretical value to calculate the verification coefficient and bridge carrying capacity evaluation is performed according to the specifications of bridge carrying capacity evaluation.

The invention relates to the field of high-temperature alloy forging, and particularly relates to a CH4169 alloy forging piece grain size analysis and predication method. The CH4169 alloy forging piece grain size analysis and predication method comprises the following steps: carrying out a near isothermal forging experiment on a CH4169 alloy sub-size double-cone test sample; carrying out finite element simulation on a near isothermal forging experiment process to obtain forging thermal parameters of the test sample; determining the grain size and determining forging thermal parameter values according to a finite element calculation result; drawing a contour map of the relation of the grain size and the forging thermal parameters according to the obtained grain size and forging thermal parameters; carrying out the finite element simulation on an actual production process of a CH4169 alloy forging piece, and counting the forging thermal parameters; and determining the grain size of a part to be analyzed and predicated by utilizing the drawn contour map of the grain size and the forging thermal parameters. According to the CH4169 alloy forging piece grain size analysis and predication method, the established contour map of the relation of the grain size and the CH4169 alloy forging thermal parameters is used for analyzing and predicating the grain size in the CH4169 alloy forging piece, and the method is convenient to use and has the high predication accuracy.

A simplified method for forecasting the fatigue expansion service life of an inclined crack in the center of a rectangular plate mainly comprises five steps: step I, parametric modeling; step II, meshing; step III, finite element calculation and result reduction; step IV, automatic crack expansion simulation through cycle call; and step V, crack expansion service life forecasting. The method is based on Python language, carries out ABAQUS secondary development, adopts parametric modeling, and compiles command stream software packages for modeling and analysis, can realize automatic simulation of crack expansion of the rectangular plate with the central inclined crack, is low in workload, and high in precision.

The present invention relates to a method for determining a fluctuation wind induced vibration load of a power transmission tower. The method comprises: determining a fluctuating wind velocity power spectrum density function; generating a random fluctuating wind velocity sample by decomposing a matrix of the fluctuating wind velocity power spectrum density function; and according to the fluctuating wind velocity sample, determining the fluctuation wind induced vibration load. The technical scheme of the present invention is applicable to general power transmission towers and the generated wind induced vibration load data can be directly used for performing finite element analysis, so that finite element calculation research in wind induced vibration time history analysis of the power transmission towers is greatly facilitated.

The invention discloses a three-dimensional magnetic flux leakage testing defect contour reconstruction method and a device. The three-dimensional magnetic flux leakage testing defect contour reconstruction method comprises following steps: a forward finite element calculation model is constructed; characteristic constants of a defect magnetic flux leakage field are extracted; initial estimate values of defect contour parameters are obtained based on the characteristic constants, and the initial estimate values are introduced into the forward finite element calculation model as input values for iterative computations so as to obtain leakage magnetic field predicted values, wherein the defect contour parameters are updated via heuristic optimization algorithm so as to obtain defect contour parameter expectancy values and realize defect reconstruction. The three-dimensional magnetic flux leakage testing defect contour reconstruction method is capable of increasing defect reconstruction efficiency; stability is high; calculation is accurate; and speed is high; so that it is beneficial for increasing of reconstruction speed and precision of irregular defects.

The present invention provides a three-dimensional magnetic flux leakage detection defect complex inversion imaging method which comprises a step of obtaining an imaging area from a pipeline to be detected, a step of scanning the pipeline to be detected to obtain a magnetic flux leakage field detection value, a step of constructing a reverse radial basis function neural network model and inputting the magnetic flux leakage field detection value to obtain the initial value of a defect profile parameter, a step of constructing a positive finite element calculation model, inputting the initial value of a defect profile parameter, and obtaining a magnetic flux leakage field detection value, a step of judging whether the error between the magnetic flux leakage field detection value and a magnetic flux leakage field preset value is smaller than or equal to a preset error threshold, if so, realizing defect imaging according to the initial value of the defect profile parameter, and if not, updating the initial value of the defect profile parameter, and inputting the finite element calculation model to carry out iterative calculation again until the error is smaller than or equal to the preset error threshold. According to the method, the problem of excessive iterations in a conventional closed loop iterative method is reduced, and the method has the advantages of high practicability, good stability and high imaging precision.

A nonlinear multi-target range robust optimization based automobile noise reduction method comprises the steps of 1, conducting mathematical modeling for performance indexes, determining design variables of an automobile structure, determining a noise index at an observation point according to finite element calculation results, and establishing a multi-target optimization model; 2, describing all uncertain parameters of a system with ranges; 3, on the basis of range order relations and sensitivity analyses, conducting robustness processing of objective functions on the noise index; 4, on the basis of range possibility degrees, conducting feasible robustness conversion on constraint conditions; 5, converting a two-layer nesting optimization problem into a conventional single-layer optimization problem with an improved Taylor expansion method; and 6, solving the converted certainty multi-target optimization problem, and determining design values of all components of an automobile to achieve the optimal noise reduction effect. By the aid of the method, the automobile noise reduction problem containing range parameters can be solved systematically, the insensitivity to parameter fluctuations is improved, and the usage safety of the automobile structure and the stability of the noise reduction performance are improved.

The invention provides with a remote finite element analysis method serving for an industry alliance. The remote finite element analysis method comprises the steps of (1) finite element template extraction, namely classifying and analyzing parts needing finite element analysis in the products of member enterprises in the industry alliance, and extracting finite element templates, including boundary condition types and analysis process parameters, (2) geometric model construction, namely performing geometric modeling on the structures of the needing finite element analysis in the products of the member enterprises in the industry alliance by use of a CAD (Computer-Aided Design) system mainly in a parametric modeling manner and a user-defined modeling manners, (3) boundary condition calibration, namely performing necessary calibration on pels, to which the boundary conditions are applied, in geometric models, thereby taking the geometric models as parameter input interfaces of finite element analysis, (4) finite element model conversion, namely converting the geometric models into finite element models by use of ANSYS Workbench, (5) remote finite element calculation, namely completing remote finite element analysis on the parts by controlling a collaborative simulation environment by use of a command stream, (6) finite element analysis result feedback, namely realizing three-dimensional visual feedback of the finite element analysis results by use of WebGL technology, and (7) public service platform implementation.

The invention discloses a method for judging the icing instability of a tension support of a power transmission line. The method comprises the following steps that: S1: establishing a pole and tower finite element mechanical analysis fine numerical simulation model; S2: solving and calculating the force direction and the change amount of an insulator string mount point before and after the pole and tower is iced; S2: carrying out finite element numerical calculation; S4: considering an influence of practical uneven icing of two sides of a tension support structure, and making an pole and towerinstability curve; and S5: according to the tension or icing thickness practicality of the mount point under an icing condition, judging a current power transmission line pole and tower instability situation. By use of the method, the real-time tension of the insulator string mount point, finite element situation calculation is adopted to researching the influence of the icing on the pole and tower instability, calculation efficiency can be effectively improved, a finite element calculation result is more reliable, and power grid maintenance personnel can conveniently and directly evaluate the pole and tower stability on the basis of the monitoring situation of the insulator string tension of two sides of the pole and tower.

The invention relates to civil excavation engineering technology and aims to better predict the rebound caused by foundation pit excavation by comprehensively considering the spatio-temporal effect in soil mass unloading process and the upheaval of the foundation and the tunnel under the condition of foundation reinforcement for the foundation pit. According to the technical scheme, a method of estimation on the underlying tunnel and foundation rebound in the excavation of a foundation pit includes the steps of firstly, calculating residual stress influence depth hr under foundation reinforcement, namely determining unloading influence depth after foundation pit excavation under foundation reinforcement; secondly, correcting according to a soil mass unloading modulus formula and according to finite element calculation results to determine unloading modulus of the soil mass below the excavation face of the foundation pit; and thirdly, calculating the unloading stress average and the corrected soil mass unloading modulus to obtain the magnitude of foundation rebound in the range of residual stress influence depth, and obtain rebound deformation of the underlying subway tunnel. The method is mainly applied to civil excavation.

The invention discloses a modal analyzing method for a high-frequency blade based on noncontact vibration measurement and simulating calculation. The modal method can meet modal analysis in the high-frequency range from 1000 Hz to 15000 Hz, and comprises the following steps that firstly, a free mode and vibration mode are calculated by using a finite element calculation method; secondly, accordingto a free mode calculation result, a measurement point is selected, a blade origin frequency response function is measured by using a laser Doppler vibration measurement technology, and the actual inherent frequency of the blade is obtained; thirdly, the elasticity modulus and the Poisson's ratio parameter of a simulation model are corrected, so that the calculation result of the simulation modelis consistent with the actual inherent frequency, work boundary conditions are applied to the corrected simulation model, and the blade mode in a work state is calculated. By means of the method, theprecise modal frequency and vibration mode can be obtained for the high-frequency blade, and a reliable analysis reference is provided for engine blade resonance, fatigue failure and other faults.

The invention relates to a pipeline valve safety assessment method based on limit external load calculation. The method comprises steps as follows: S1, establishing a three-dimensional geometrical model of a valve, a pipeline and a connecting piece; S2, performing finite element mesh generation on the three-dimensional geometrical model to establish a finite element mesh model; S3, establishing a limit external load finite element calculation model on the finite element mesh model; S4, performing calculation according to the limit external load finite element calculation model to obtain a limit external load; S5, establishing multiple combined external load finite element calculation models under the combined action of the limit external load and the maximum working pressure on the finite element mesh model; S6, calculating the stress distribution of the pipeline valve through the combined external load finite element calculation models and determining the safety performance of the pipeline valve according to the stress distribution. With the adoption of the method, the effect caused by the external load on the pipeline valve can be considered before prototype production, whether the strength property of the valve meets the design requirement or not can be judged, potential risks can be predicted, and the product development cycle is shortened.

The invention provides a method for determining plastic forming limit of sheet material based on finite element calculation analysis. The method of the invention comprises the following steps: (1) obtaining the elastic modulus, Poisson's ratio, yield strength and post-yield stress of the sheet material Strain correspondence; (2) establishing the geometrical models of punch, concave die, blank holder and sample; (3) adding the corresponding material properties and setting the corresponding friction coefficient in the material model of the finite element software; 4) determining that applied load accord to the actual downward pressure amount and downward pressure of the blank holder ring; (5) controlling the downward pressing displacement of the punch, that is, the downward pressing amount;(6) meshing the sample; (7) defining the calculation time; (8) obtaining the results of stress-strain evolution in a sample forming experiment, and outputting the stress-strain nephogram of all the units; (9) using S-G filter to perform first and second order fitting on main strain. The invention provides reliable judging basis and criterion for obtaining accurate results of sheet metal stamping forming.

The invention discloses a high-rockfill-dam transient-rheological-parameter inversion method based on the response surface method.The method includes the steps that a rockfill-dam three-dimensional finite element model is built in combination with dam body material sections and construction grading conditions, the sensitivity of the transient parameters and the rheological parameters of rockfill of the material sections is analyzed, and the transient parameters with the high sensitivity and the rheological parameters with the high sensitivity are selected as to-be-inversed parameters jointly; a material static force model is a Duncan EB model, and a rheological model is a Nanjing-Hydraulic-Research-Institute five-parameter model; the implicit relationship between the finite-element-calculated settling volume and the calculation parameters is represented through a specific-form response surface function, undetermined coefficients of a response surface equation set are solved through several times of finite element calculation, and therefore the nonlinear mapping relationship between the settling volume and the calculation parameters is built.On the bases of the response surface equation, the objective function aims at obtaining the minimum root-mean-square error between the calculated settling volume and the practically-measured settling volume, the transient parameters and the rheological parameters are inversed with the genetic algorithm at the same time, and the obtained set of optimal calculation parameters are the inversion result.

The invention relates to a multi-block slide calculation method for a giant landslide, and belongs to the field of geological disaster engineering. The method is used for landslide disaster stability evaluation and engineering prevention and control. The method comprises the steps of: (1) finding out a landslide region range, deformation features and hydrogeology and engineering geology conditions; (2) based on a finite element program, establishing a finite element numerical model of a side slope; (3) inputting formation mechanical parameters of the side slope; (4) inputting reduction parameters and physical and mechanical characters of landslide massif for performing finite element calculation; (5) determining a side slope failure region; (6) continuously reducing failure strength parameters until slide surfaces are communicated; (7) determining a tension failure zone of each stage of slide surface; (8) setting the tension failure zone as a null unit in the model; and (9) re-calculating a new numerical model and searching out multiple stages of slide surfaces. According to the multi-block slide calculation method for the giant landslide, provided by the invention, the multiple stages of slide surfaces of the giant landslide can be accurately searched out and an important basis is provided for giant multi-stage landslide stability evaluation and engineering prevention and control.

The invention discloses a structure topology optimization design sensitivity filter method based on a density threshold value, which is used for solving the technical problem that the manufacturability of topology optimization design structure of a conventional structure topology optimization design sensitivity filter method is poor. The method adopts the technical scheme that firstly, a topology optimization model is constructed; and secondly, unit sensitivity and unit pseudo-density are obtained via finite element calculation, unit number n of a model unit pseudo-density xi value is calculated, which is within a given range, a medium unit percentage C is calculated, if the percentage C of a step k of optimization iteration is less than a density threshold value T, sensitivity filter for a step k+1 is forbidden till the optimization iteration is over, optimization design is executed by adopting an optimization criteria method, and a topology optimization result of a two-dimensional simple supported beam, thus the manufacturability of the topology optimization structure is enhanced. With the adoption of a density threshold value method, iteration steps required by the structure topology optimization design are decreased by 71 steps from 112 steps of constringency to 41 steps of constringency compared with a background art.

The invention relates to a high-level assessment method for defects of a welding joint area at a piping safety end of a pressure vessel of an AP1000 nuclear reactor. The method comprises the following steps of: characterizing the detected dimensions of unpenetrated circumferential inner surface defects; establishing a failure assessment graph, wherein the failure assessment graph comprises the family of the failure assessment curves of the unpenetrated circumferential inner surface defects in the different dimensions, which are acquired on the basis of three-dimensional finite element calculation; selecting the failure assessment curves according to the dimensions of the defects; based on the three-dimensional finite element calculation, calculating the family of the curves that stress intensity factors change along an extra resultant bending moment at the deepest points of the unpenetrated circumferential inner surface defects in the different dimensions; determining the stress intensity factors according to the resultant bending moment and the dimensions of the defects; calculating a specific breaking strength parameter Kr; based on the three-dimensional finite element calculation, acquiring the family of the ultimate load bending moment curves of the unpenetrated circumferential inner surface defects in the different dimensions; determining ultimate load bending moments according to the dimensions of the defects; calculating a load ratio parameter Lr; and marking a calculated coordinate (Lr, Kr) on the failure assessment graph, and judging whether falling into an area which is encircled by the selected failure assessment curves, a vertical end line and coordinate axes or not.

The invention discloses a determination method of a material's uniaxial constitutive relation through biconical indentation prediction. By the use of two different diamond cone indenters (shaped as a cone or a right square pyramid), a smooth material's surface undergoes quasi-static indentation loading so as to obtain a continuous loading P-depth h curve; loading curvature C is obtained through the curve loading section; and through simple treatment, the material's uniaxial constitutive relation is predicted. By the method, the defect that existing cone indentation technology requires long-range finite element calculation and depends on multistage regression fitting to obtain complex numerical relationship and the like is overcome, and harsh technological requirements for solution to constitutive relation in the prior art are avoided. The method of the invention can be used in mechanical effects analysis of material's constitutive relation and relevant factors under loading conditions such as creep deformation, impact and the like. The invention is of great significance for acquisition of uniaxial mechanical properties of materials with a small structure or a welding structure widely existing in key projects such as micro electro mechanical system, aerospace, nuclear power, high-speed railway, oil and gas transportation, biomedical engineering and the like.