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43 results about "Virtual displacement" patented technology

In analytical mechanics, a branch of applied mathematics and physics, a virtual displacement δrᵢ "is an assumed infinitesimal change of system coordinates occurring while time is held constant. It is called virtual rather than real since no actual displacement can take place without the passage of time." Also, virtual displacements are spatial displacements exclusively - time is fixed while they occur.

Method for computing electromagnetic force of transformer iron core based on finite element method

The invention discloses a method for computing electromagnetic force of a transformer iron core based on a finite element method. The method comprises the steps that structural parameters of a winding, the iron core and a fuel tank of a transformer are collected, and then a three-dimensional geometric grid model of the transformer is established; the three-dimensional geometric grid model is input into software, sinusoidal currents with a phase different of 120 DEG are applied to the cross section of the three-phase low voltage winding respectively, and Dirichlet boundary conditions are applied to the outer side of the structural grid model; and an instant electromagnetic field is solved by a virtual displacement method, magnetic field energy is computed, a virtual work method is used to compute instant electromagnetic force borne by the transformer iron core and the winding, FFT is conducted to the instant electromagnetic force, and frequency domain distribution of the electromagnetic force of the iron core can be obtained. The computation method disclosed by the invention is direct and convenient; electromagnetic vibration and force bearing situations of the transformer iron core can be analyzed from the perspective of energy; each influential factor on force bearing of the iron core is considered comprehensively; and computation results are accurate and reliable.
Owner:CHINA ELECTRIC POWER RES INST +1

Cable buckling modeling method

The invention discloses a cable buckling modeling method. The modeling method comprises the steps of performing node division on an original whole cable core wire according to a change property of a geometric shape; decomposing the cable core wire into small units; constructing a corresponding stiffness matrix; and establishing a balance relationship by adopting a virtual displacement principle. Any point P is obtained in the cable core wire, and a tiny parallelepiped is cut, wherein the edge lengths in x, y and z directions are dx, dy and dz respectively. Firstly, a straight line for connecting the centers of the front and back surfaces of the hexahedron is taken as a moment axis; a balance equation sigma Mee'=0 of moments is listed out; and two similar equations are obtained according to the rest of two balance equations sigma Fy=0 and sigma Fz=0. According to the modeling method, a buckling stress generated during excessive cutting of cable wire cores with different lengths based on ANSYS finite element software is simulated, an influence law of core wire length on casing stress is analyzed, a simulation result shows that the casing stress is remarkably reduced with increment of the cable wire core length, and a reasonable casing height is given. A theoretical basis is provided for reasonable design and installation of a cable terminal of a ring main unit.
Owner:CHINA THREE GORGES UNIV

Transformer substation inspection robot navigation system and transformer substation inspection robot navigation method

ActiveCN109031373AImprove Outdoor Navigation AccuracyImprove stabilitySatellite radio beaconingReal time navigationTransformer
The invention discloses a transformer substation inspection robot navigation system and a transformer substation inspection robot navigation method. The transformer substation inspection robot navigation system comprises a robot body and a ground station. The ground station is used to transmit difference information to the robot body. The robot body is used to process the difference information toacquire positioning information, and the robot body is used to acquire first measuring navigation information of a current mobile station by virtual displacement information, gesture information, andpositioning information through a fusion algorithm, and the virtual displacement information and the gesture information are provided by the robot body. The robot body is used to establish a raster map according to polar coordinate information, and according to the raster map and the polar coordinate information, the second measuring navigation information of the current mobile station is acquired. The robot body is used to fuse the first measuring navigation information and the second measuring navigation information by Kalman filtering to acquire real-time navigation information. Accordingto the invention, automatic navigation capability is provided, and outdoor navigation precision and navigation stability are greatly improved.
Owner:BEIJING AEROSPACE GUANGHUA ELECTRONIC TECH CO LTD

Design method of compact plane structure parabolic reflector antenna based on meta-material

The invention discloses a design method of a compact plane structure parabolic reflector antenna based on meta-material. The design method comprises the following steps that a feed source unit with a plane boundary is designed by using the principle of transformation electromagnetics; a plane structure parabolic reflector is adopted to replace a conventional curved surface structure parabolic reflector to act as the reflecting surface of the reflector antenna; and the plane reflector and the feed source unit are combined to be designed into the compact plane reflector antenna. The plane reflector is adopted to act as the reflecting surface and the reflecting characteristics of the plane reflector are equivalent to those of the conventional parabolic reflector; the designed feed source unit is transparent to rays without blocking to the rays, and the radiation characteristics of a feed source arranged in the feed source unit are equivalent to the radiation characteristics generated by the feed source arranged at the position far from the reflecting surface due to the virtual displacement effect generated by the metal-material; and the reflector and the feed source unit are combined together in the reflector antenna to form a compact structure so that the phenomenon of separation of the reflecting surface and the feed source in the conventional reflector antenna can be avoided.
Owner:SHANGHAI NORMAL UNIVERSITY

Sensitivity solving method under multiple displacement constraints

The invention discloses a sensitivity solving method under multiple displacement constraints. The sensitivity solving method comprises the following steps: constructing an airplane structure optimization model, and acquiring variables, boundary conditions and displacement constraint information of the optimization model under respective working conditions; performing static analysis, and calculating a real displacement; grouping the working conditions according to the boundary conditions and the displacement constraints to obtain a real displacement matrix U; performing reduction K according to the boundary conditions to form Ki; defining a virtual load array Pri according to the displacement constraints; solving the equation set Ki*Upsei=Pri; calculating unit differential matrixes Kde, and assembling a structural differential matrix Kd; and extracting respective columns of the real displacement matrix U, transposing the columns, multiplying the columns with corresponding columns of the structural differential stiffness matrix Kd and a virtual displacement array Upse to obtain each displacement constraint sensitivity of the current variable. The method solves the problem of sensitivity solving of multiple displacement constraints under different working conditions; no assumption of a boundary of a virtual working condition is needed in advance; and when a static balance equation is solved, the data reusability is considered, so that a sensitive information-based planning method can be applied to structural optimization problems under global constraints such as displacement.
Owner:CHINA AIRPLANT STRENGTH RES INST

Linkage locking anti-rebounding civil defense door utilizing fluid pressure

The invention relates to protective equipment in the field of civil defense engineering and national defense engineering and discloses a linkage locking anti-rebounding civil defense door utilizing fluid pressure. The linkage locking anti-rebounding civil defense door comprises a door frame, door leaves, fluid pressure systems arranged on the door leaves, and lock heads used for opening and closing. The door leaves and the door frame are connected through hinges; each fluid pressure system comprises a pump, a reversing valve, pipelines and a plurality of double-effect pressure cylinders; the pumps communicate with the reversing valves, and the reversing valves communicate with the double-effect pressure cylinders through pipelines; the lock heads are in matched connection with the double-effect pressure cylinders and comprise lock bodies and sliding lock cylinders; lock boxes matched with the lock cylinders correspondingly are arranged on the door frame; and limiting grooves are formedin the lock cylinders, and limiting blocks in sliding fit with the limiting grooves are arranged on the lock bodies. The fluid pressure system in the linkage locking anti-rebounding civil defense door can keep the stable pressure in a long term, and the pressure is transmitted through fluids, so that operation is easier, linkage is more stable and more reliable, and virtual displacement is avoided; and synchronous linkage arrangement is conducted, and thus synchronization of the multiple lock heads at the time of executing unlocking and locking is better; and therefore, the locking anti-rebounding civil defense door is worth popularizing.
Owner:张阳鑫

Method for calculating drilling layering critical axial force of composite material plate by considering deformation

The invention discloses a method for calculating drilling layering critical axial force of a composite material plate by considering deformation. The method is characterized in that: aiming at the drilling layering defect of the carbon fiber composite material with smaller thickness, the influence of the bending deformation of the composite material component on the drilling layering in the drilling process is considered, and the critical axial force for generating the layering defect is calculated, and then the layering defect in the drilling process is effectively predicted; and meanwhile, the combined action of a tool chisel edge and a main cutting edge is considered, and the axial force borne by the tool chisel edge part is equivalent to the concentrated force effect, and the axial force borne by the tool main cutting edge is equivalent to the uniform distribution force effect, and the drilling layered critical axial force considering the overall and local bending deformation of the composite material is finally obtained by applying the virtual displacement principle. According to the method, the stress condition of the tool in the drilling process and the deformation conditionof the composite material are fully considered; the carbon fiber composite material drilling layering defect prediction model is established; the drilling layering critical axial force is calculated;and the method has a very good effect on inhibiting the drilling layering defects of the carbon fiber composite material.
Owner:DALIAN UNIV OF TECH

Virtual displacement tester for measuring virtual displacement of reduction gear unit

The invention is applicable to the technical field of measuring devices, and provides a virtual displacement tester for measuring virtual displacement of a reduction gear unit. The virtual displacement tester comprises a base, a main control board, a display screen, an adjusting mechanism and a bilateral adjusting component, the adjusting mechanism comprises a rudder arm, a magnetic ring, a sub-circuit board, an angle sensor, a horizontal adjusting component and a vertical adjusting component, the rudder arm is mounted on an output shaft, the angle sensor is opposite to the magnetic ring, and the angle change of the magnetic ring is detected by the aid of the angle sensor. According to the virtual displacement tester for measuring virtual displacement of the reduction gear unit, the magnetic ring is mounted on the rudder arm, the position of the angle sensor relative to the magnetic ring on the sub-circuit board is adjusted by the horizontal adjusting component, the vertical adjusting component and the bilateral adjusting component, so that the angle sensor is adjusted to be aligned to the magnetic ring, the aligning position of the angle sensor and the magnetic ring is kept, and the angle change of the magnetic ring is detected by the aid of the angle sensor to effectively test virtual displacement errors of the reduction gear unit.
Owner:UBTECH ROBOTICS CORP LTD

Design method applied to mooring system

The invention discloses a design method applied to a mooring system, which comprises the following steps of: (1) setting wind power Ff in the horizontal direction as main power, taking the position ofa connecting point of an anchor and an anchor chain as an origin of coordinates, taking a seabed as an X axis and taking the direction vertical to the seabed as a Y axis, establishing a generalized coordinate system and drawing a coordinate schematic diagram; (2) carrying out stress analysis from top to bottom from the buoy, and sequentially establishing virtual work equations of the buoy, the steel pipe, the steel barrel, the heavy ball and the anchor chain; (3) solving a constraint virtual displacement equation of the buoy, the steel pipe, the steel barrel, the weight ball and the anchor chain according to the virtual work equation of the buoy, the steel pipe, the steel barrel, the weight ball and the anchor chain; (4) constructing an objective function from the generalized coordinate system; and (5) solving a nonlinear equation set composed of a virtual work equation and a constraint virtual displacement equation according to the objective function, and calculating the inclinationof the anchor chain, the steel barrel and the steel pipe, the depth of the buoy entering water and the floating range of the buoy.
Owner:HUNAN INSTITUTE OF SCIENCE AND TECHNOLOGY

400Hz structural performance balanced cable for ships and manufacture method thereof

The invention relates to a 400Hz structural performance balanced cable for ships and a manufacture method thereof. The centers of three composite cable cores are connected into a regular triangle; the center of each composite cable core is a power cable conductor and is extruded and wrapped with a power cable insulating layer, and the periphery of each power cable insulating layer is provided with an insulating wire core set which is formed in a twisting way; ten grounding conductors are divided into two sets and are symmetrically arranged around each power cable insulating layer; eight control wire cores are divided into four sets, and are respectively arranged into two sets between two sets of grounding conductors, and a virtual displacement member is respectively arranged among each set of the control wire cores and between the control wire cores and the grounding conductors; the outer diameters of each grounding conductor, control wire core and virtual displacement member are the same as one another and are distributed on the same circle; the periphery of the insulating wire core set is extruded and wrapped with an internal protecting bush, and the periphery of the internal protecting bush is extruded and wrapped with an external protecting bush; and the external protecting bushes of the three composite cable cores are tangent with one another two by two and are glued into a whole. The cable simultaneously has the functions of a power cable and a control cable, and is balanced in structure and small in outer diameter and bending radius.
Owner:JIANGSU YUANYANG DONGZE CABLE

Dam state prediction method and system based on data assimilation

ActiveCN114547951AAdjust the direction of evolution in real timeImprove estimation accuracyGeometric CADClimate change adaptationState predictionAlgorithm
The invention discloses a dam state prediction method and system based on data assimilation, and belongs to the technical field of dam state prediction. According to an existing dam state prediction method, the calculation precision is extremely dependent on correct description of a concrete material constitutive model, generally, model parameters can only be obtained from prototype observation or twinborn experiments, and determination and calibration of the parameters are complex. According to the method, the nonlinear evolution characteristic of a concrete material along with time is fully considered, a data assimilation model is constructed by utilizing a dam body virtual displacement field and the displacement amount of an actual dam measurement point at the same moment, and displacement back analysis is performed on linear elastic constitutive parameters of the concrete material of the dam; observation data is introduced into the data assimilation model for model updating, the influence of data errors on the model is fully considered, and the evolution direction of the data assimilation model is adjusted in real time, so that the estimation precision of the data assimilation model is improved, the prediction capability of a prediction model is effectively improved, and important reference data can be provided for real-time early warning analysis of a dam.
Owner:浙江远算科技有限公司 +1

Inverse problem design method for quasi-s1 flow surface of axial flow compressor

The invention provides an inverse problem design method of a pseudo S1 flow surface of an axial-flow compressor. The method comprises the steps of selecting an axial-flow compressor blade; calculatingcoordinates of upper and lower molded lines, and constructing the pseudo S1 flow surface to obtain flow field flow conditions and flow parameter distribution; obtaining a new load distribution curvethrough a parameterization method; calculating the virtual moving speed and the corresponding virtual displacement of an arc surface in the pseudo S1 flow surface; updating grid calculation domain boundaries and internal grid node coordinates; carrying out at least five pseudo S1 flow surface inverse problem designs with multiple design sections on the compressor blade; calculating the inverse problem to obtain the blade profile geometry of each design section meeting the target load; generating a new full-blade-height compressor blade geometry through geometric stacking; and verifying the aerodynamic performance of the new compressor blade through full three-dimensional viscous positive problem calculation. According to the inverse problem design method of the pseudo S1 flow surface of the axial-flow compressor, the load distribution of the pseudo S1 flow surface is given autonomously, the inverse problem modification design is carried out on the initial blade, and finally the new blade geometric configuration meeting the target load distribution is obtained.
Owner:NORTHWESTERN POLYTECHNICAL UNIV

An identification method of road driving quality based on inverse virtual excitation method

ActiveCN107894223BAccurate and real-time identificationImprove efficiencyMeasurement devicesMatrix inverseVirtual displacement
The invention discloses a road surface riding quality identification method based on an inverse virtual excitation method. The road surface riding quality identification method comprises the steps ofestablishing a 1 / 2 vehicle 6-DOF system model, obtaining a frequency response function matrix [H(f)] of the system, and based on a matrix inverse transformation method, solving for a generalized inverse matrix [H(f)]+ of the frequency response function matrix of the system; obtaining an unsprung mass and centroid vertical acceleration of a front axle and an unsprung mass and centroid vertical acceleration of a rear axle, obtaining a vehicle body centroid vertical acceleration and a vehicle body pitch acceleration, and constructing a vertical displacement response vector {z-tilde(t)} of the system using a fast Fourier transform method; according to the generalized inverse matrix [H(f)]+ and the virtual displacement response vector {z-tilde(t)}, solving for an effective road surface virtualexcitation vector {qe-tilde(t)}, and according to a time domain transfer function H(f)qe~qr of tire containment characteristics, solving for an actual road surface virtual excitation vector {qr-tilde(t)}; and according to the actual road surface virtual excitation vector {qr-tilde(t)}, solving for an international roughness index (IRI) of the spatial frequency to further obtain the road surface riding quality index (RQI). The method is simple to operate and high in efficiency.
Owner:JILIN UNIV

Geometric nonlinear analysis method for CFRP (carbon fiber reinforced plastic) laminated plate in humid and hot environment

InactiveCN113486496AClose to goodGood methodDesign optimisation/simulationSpecial data processing applicationsFiberShear deformation theory
The invention relates to a geometric nonlinear analysis method for a carbon fiber reinforced plastic (CFRP) laminated plate under the action of uniformly distributed load in a humid and hot environment, and belongs to the technical field of modern engineering structure analysis and application, namely the influence of a humid and hot effect is considered in a CFRP engineering structure based on a Reddy high-order shear deformation theory. According to the method, aiming at solving the problem of damp and hot deformation in engineering materials, a geometric nonlinear control equation is deduced by utilizing a virtual displacement method, and the boundary condition is considered to be elastic limited rotation; then, physical parameters of the CFRP are regarded as constants in the damp-heat effect, a Galerkin method is used for solving a control equation, and the clamped rectangular CFRP laminated board is used; according to the method, the damp-heat deformation prediction of the engineering structure is realized by utilizing a nonlinear analysis method, a new method is provided for the structural damage prediction of the CFRP, and the method has certain guiding significance in reducing composite material structure accidents.
Owner:HUNAN UNIV

Numerical method and system for simulating crack tip stress field

The embodiment of the invention relates to a numerical method and system for simulating a crack tip stress field, and the method comprises the steps: employing two-dimensional geometric description inparameter coordinates of a crack tip region, and obtaining a two-dimensional geometric description formula of the crack tip region according to a crack curve and a circumferential boundary curve; converting the two-dimensional geometric description formula into a displacement approximate expression of a crack tip region by utilizing a one-dimensional basis function in a xi direction and a one-dimensional basis function in an eta direction; converting an expression of a virtual displacement principle into a weak form in a crack tip region based on a linear elasticity problem equation; obtaining a solving equation formed by a rigidity matrix, a force vector and a displacement vector according to the displacement approximate expression in combination with a weak form; and solving a variableto be solved according to the solving equation, and obtaining a stress field of the crack tip region based on solving of the variable to be solved and the like. According to the invention, the crack tip stress field can be accurately simulated, the stress solution can gradually converge to an accurate solution, and the precision and stability of numerical simulation are improved.
Owner:CHINA SPECIAL EQUIP INSPECTION & RES INST

Method for solving continuous beam support counterforce

The invention relates to a method for solving continuous beam support counterforce and belongs to the technical field of structural mechanics. The invention particularly relates to a method for solving the continuous beam support reaction force. The method for solving the continuous beam support counterforce provided by the invention has the advantages of accurate and reliable calculation result and simple calculation process, and the method is a matrix lever method. According to the method, a support counterforce value is calculated by uniformly compiling numbering codes for supports, establishing a matrix lever method basic system, listing linear equations, listing matrixes, selecting basic structure calculation coefficients and free items and inputting coefficient and free item calculation results into a matrix. The matrix lever method is based on lever principle moment balance and is not based on a virtual work principle and the assumption of structural virtual displacement, the calculation method is single, disorder is not prone to occur after the numbering codes are compiled on the supports in a unified mode, the calculation is mostly repeated calculation work, the programming is simple, the calculation result precision is high, the universality is high, and the computer program operation is easy to achieve.
Owner:王开明

A Modeling Method for Cable Buckling

The invention discloses a cable buckling modeling method. The modeling method comprises the steps of performing node division on an original whole cable core wire according to a change property of a geometric shape; decomposing the cable core wire into small units; constructing a corresponding stiffness matrix; and establishing a balance relationship by adopting a virtual displacement principle. Any point P is obtained in the cable core wire, and a tiny parallelepiped is cut, wherein the edge lengths in x, y and z directions are dx, dy and dz respectively. Firstly, a straight line for connecting the centers of the front and back surfaces of the hexahedron is taken as a moment axis; a balance equation sigma Mee'=0 of moments is listed out; and two similar equations are obtained according to the rest of two balance equations sigma Fy=0 and sigma Fz=0. According to the modeling method, a buckling stress generated during excessive cutting of cable wire cores with different lengths based on ANSYS finite element software is simulated, an influence law of core wire length on casing stress is analyzed, a simulation result shows that the casing stress is remarkably reduced with increment of the cable wire core length, and a reasonable casing height is given. A theoretical basis is provided for reasonable design and installation of a cable terminal of a ring main unit.
Owner:CHINA THREE GORGES UNIV
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