90 results about "Shell element" patented technology

The invention relates to the field of thin-wall structure displacement field monitoring, and discloses a coupled functional unilateral inverse finite element cylindrical thin-wall structure displacement field monitoring method, which comprises the following steps of: performing discretization by adopting a four-node inverse shell unit, and arranging a sensor at a geometric center position of each unit; based on the basic mathematical model of the inverse finite element, establishing an overall pseudo-stiffness matrix and an overall pseudo-force matrix; and calculating to obtain a displacement field of the structure by solving a linear equation set formed by the overall pseudo-stiffness matrix, the overall pseudo-force matrix and the global displacement vector. According to the method, the structural displacement field is calculated by using the strain information measured at one side, and the global deformation is accurately and reversely deduced under the condition that only the local strain data is obtained by combining the advantages of finite element analysis and inverse problem solution. By optimizing local strain data solution, high cost and low efficiency of global strain measurement in a traditional method are avoided, and the method has remarkable practical advantages.

The invention relates to a slamming strength evaluation method for a duct fin at the tail of a ship, which comprises the following steps of: (1) establishing finite element models of the duct fin and an adjacent ship body structure, and setting boundary conditions; (2) selecting the lower surface of the upper region of the conduit and the lower surface of the fin as slamming pressure acting surfaces, and calculating a slamming pressure peak value of each point; (3) applying slamming pressure to the finite element model, and applying a slamming pressure peak value as a static load to a plurality of local areas of the conduit and the fin to generate different loading conditions; and (4) calculating the structure response, evaluating the Von Mises stress of the plate shell unit and the axial stress of the rod unit, and judging whether the Von Mises stress and the axial stress meet the allowable stress related to the grid size or not. Compared with a method for calculating the slamming load based on CFD, the slamming strength evaluation method has the advantages that the calculation efficiency is extremely high, and the slamming strength of the conduit fin can be quickly evaluated in a short time; the method is more suitable for slamming pressure calculation of the tail conduit fin, and the considered loading mode is more comprehensive.

The invention belongs to the technical field of mechanical simulation and prediction of woven fabrics, and particularly discloses a modeling method and system for simulating wrinkles of a multi-layer woven fabric, and the method comprises the steps: building a numerical model considering the characteristics of the multi-layer woven fabric, and enabling the multi-layer woven fabric to be formed by stacking single-layer woven fabrics according to a target layering sequence; determining a numerical value implementation method of the numerical value model in the finite element framework, wherein the numerical value implementation method is implemented through a subprogram interface; simulating the wrinkle defect generated in the deformation process of the two-dimensional woven fabric by adopting the finite element framework according to the numerical model through the numerical implementation method; wherein the numerical model is established by simulating tensile deformation, shear deformation and bending deformation of a single-layer fabric through shell units of the multi-layer woven fabric and indirectly simulating compression deformation and interlayer slippage behaviors through contact interaction among the shell units. According to the invention, the accuracy of wrinkle defect simulation of the multi-layer woven fabric can be improved.

The application belongs to the technical field of electric data processing, and particularly relates to a nonlinear unit construction method based on dimension expansion. The shell unit nodes are classified and information is stored; the normal of the shell unit is calculated; new nodes are expanded on the positive and negative sides along the normal according to the thickness, and corresponding three-dimensional solid units are generated; the junctions at the unit connections are specially processed to maintain the connectivity; and the original constraint conditions are converted and applied to the expanded new nodes. The method significantly improves the calculation accuracy and boundary adaptability, greatly reduces the development complexity of the nonlinear unit, and facilitates the direct coupling analysis of beams, shells, solids and other units in a unified three-dimensional system.

The application discloses a structure nonlinear deformation reconstruction method and system based on isogeometric and reduced basis, and the method comprises the following steps: measuring initial strain data of a ship plate structure surface, constructing a plurality of four-node inverse shell elements of the ship plate based on the initial strain data; assembling the plurality of four-node inverse shell elements to obtain a whole stiffness matrix; reconstructing the whole stiffness matrix based on the measured strain data of the ship plate to obtain a linear reconstruction result of the ship plate; correcting the linear reconstruction result based on the reduced basis, and fusing the correction increment to the linear reconstruction result for nonlinear iteration to complete nonlinear deformation reconstruction. On the basis of the principle of isogeometric analysis, the application combines the inverse finite element method to establish a four-node inverse shell element, realizes high-precision ship structure displacement reconstruction through a small number of strain measuring points, and helps designers to intuitively understand and deeply understand the mechanical properties of the structure and to monitor the safety of the structure in real time.

The invention relates to a wall component (10) for producing a wall and / or a terrace support. The wall component (10) comprises a first plate-type shell element (12) and a second plate-type shell element (14), which is arranged opposite the first shell element (12), wherein the first shell element (12) and the second shell element (14) are connected by at least one reinforcing element (20) and wherein the first shell element (12) and the second shell element (14) are spaced apart from one another such that an interspace (18) for concrete material is formed between the first shell element (12) and the second shell element (14). Furthermore, the wall component (10) comprises a third shell element (16), which is concave at least in some sections and which connects the first shell element (12) and the second shell element (14) at each end such that a portion of the intermediate space (18) is delimited on five sides by means of the first shell element (12), the second shell element (14) and the third shell element (16). The invention also relates to a method for erecting a wall and / or a terrace support.

The present invention discloses a simulation analysis method for an automatic retraction structure of a double elastic rod. The elastic rod is an arc-shaped shell structure with a certain curvature and is often used as the main supporting and load-bearing component of a large spacecraft structure. The elastic rod undergoes a winding and retraction process under the action of an external load. After the locking device is opened, the elastic rod can gradually rebound and unfold by releasing the strain energy generated by bending. The principle is simple, and it is a space deployable mechanism that has been widely used. This method uses the ABAQUS finite element simulation software to assemble according to the actual spatial position of the deployable structure of the elastic rod, considers the interaction between various parts of the structure and the actual contact situation, applies a load to realize the working winding process, and selects the explicit dynamics algorithm for solution in the analysis step. A finite element model of the double elastic rod winding is established using the S4R shell element and mechanical simulation analysis is carried out. The present invention can provide a reference for the cross-section design of the winding elastic rod and the design of the system working prototype.

The invention relates to the technical field of shell unit calculation of a large-curvature curved-surface thin-wall structure. The invention provides a shell unit calculation method suitable for aviation large-curvature skin. The calculation method comprises the following steps: constructing an average plane; determining a local Cartesian coordinate system; obtaining a first balance equation, a second balance equation and a third balance equation based on the moment balance formula in the average plane and the moment balance formula of the actual element; correcting the normal load of the four-node quadrilateral unit to obtain a fourth balance equation; and adding a moment component about an average plane normal at each node i, and performing moment correction on the moment component to finally realize correction on the load of the non-coplanar four-node plate shell element. According to the load correction scheme of the non-coplanar four-node plate shell element, the analysis precision under certain warping configurations is greatly improved.

This invention provides a press forming analysis method, a press forming analysis apparatus, and a press forming analysis program that can predict press forming loads in advance, even for new part shapes and materials. [Solution] The press forming analysis method according to the present invention is a press forming analysis method that predicts the press forming load using a die model 9 having an upper die model 11 and a lower die model 17 modeled with shell elements, using the finite element method, and includes: an elastic element-attached lower die model creation step S1 in which the lower structure 7 of the press device is modeled with elastic elements 15 and attached to the lower die model 17 to create an elastic element-attached lower die model 13; an elastic modulus determination step S3 in which the elastic modulus to be applied to the elastic elements 15 is determined; and a press forming load acquisition step S5 in which press forming analysis is performed using the die model 9 including the elastic element-attached lower die model 13 modeled in the elastic element-attached lower die model creation step S1, and the press forming load is obtained.

The invention discloses a finite element shell element model modeling method and system considering metal surface corrosion random morphology. The method comprises the following steps: obtaining metal surface corrosion morphology three-dimensional point cloud data of a corroded component through three-dimensional laser scanning; performing dimension reduction on the three-dimensional point cloud data, judging whether the corrosion form of the metal surface is uniform corrosion or not, if so, calculating a physical regression equation based on the expanded point cloud data, and constructing a corrosion random morphology model based on superposition of a corresponding uniform corrosion depth on a corrosion texture generating a corresponding weight loss ratio; if not, constructing a corrosion random morphology model based on the learned corrosion texture; generating a corrosion morphology by using the corrosion random morphology model; performing regular grid division and numbering operation on the corrosion random morphology model; material attribute endowing is completed based on grid partitioning and numbering, and grid encryption division is carried out; and based on the shell element geometric model with the given thickness, parameter setting is completed, and a finite element shell element model is obtained.

The invention discloses a propeller system dynamics analysis method based on a shell unit, and the method comprises the steps: firstly determining the geometric parameters and design conditions of a propeller according to the design task and working condition of an aviation aircraft; and blade chord length distribution and mounting angle distribution are calculated based on an aerodynamic load rule, and an NACA airfoil profile is selected to generate a three-dimensional geometric model. Then, grid division is carried out according to the model, the connection relation between blade nodes and units is established, and a quadrilateral eight-node shell unit grid is formed; a finite element model is established by adopting an isoparametric element theory, a stiffness matrix and a mass matrix are calculated, and then a kinetic equation of the propeller is established. The inherent frequency and vibration mode characteristics of the blade are obtained through modal analysis, and on the basis, aerodynamic loads are applied for dynamic response analysis. According to the method, the parameterized modeling process of the propeller from geometric modeling to kinetic analysis is realized, the aerodynamic coupling vibration characteristics of the blade can be efficiently evaluated, and the method has the advantages of high modeling precision, high analysis efficiency and high adaptability.

The present invention provides a stress verification method for the main beam of a pultruded plate material used in a wind turbine blade, comprising: constructing a shell element model of the wind turbine blade, loading the shell element model in the maximum swing direction according to a design load, obtaining the strain distribution of the overall blade structure using finite element software, and extracting a first strain distribution of the main beam; constructing a solid model of the main beam chamfer area, and coupling it with the shell element model based on dynamic constraints to obtain a coupled model; loading the coupled model in the maximum swing direction according to the design load to obtain a second strain distribution of the main beam; obtaining an equivalent fatigue load based on the blade's swing direction based on the second strain distribution, and calculating the service life and safety factor of the main beam based on the equivalent fatigue load. The present invention enables more accurate verification of the fatigue life of the main beam, reduces the amount of calculation, and improves computational efficiency.

The invention relates to a storage system (1) for storing a fluid medium, preferably hydrogen, comprising at least one tank vessel (200) which has a cylindrical basic shape and has two ends (202) for storing fluid medium, in particular hydrogen, wherein the tank vessel (200) comprises: a first shell element (10), which first shell element (10) forms a tank-vessel interior (201); a second shell element (12), which second shell element (12) surrounds the first shell element (10); and an end cap element (18) at each of the ends (202). The end cap element (18) receives the first shell element (10) and the second shell element (12) at the ends (202) of the tank vessel (202). Furthermore, the first shell element (10) is fully inserted into the second shell element (12) and into the end cap element (18), and is fixed therein. The invention also relates to a method for the pressure-tight assembly of the storage system (1).

The invention discloses a parameterized propeller modeling method based on a shell unit. The parameterized propeller modeling method is used for optimizing the design of a propulsion system of an aircraft. According to the method, geometric parameters and design conditions of a propeller are determined according to a design task book and working conditions; then, based on aerodynamic load distribution, chord length changes of the blades are calculated, and the torsion rule of the blades is determined according to the inflow angle and the attack angle; furthermore, a proper NACA airfoil profile is selected, and a three-dimensional geometric section of the blade is generated, so that excellent aerodynamic performance is ensured. On the basis, the connection relation between the nodes and the units of the blades is established through grid division, and a shell unit finite element grid is formed. Constructing a shell unit model by adopting an isoparametric element theory, and calculating a stiffness matrix and a mass matrix of the blade; and finally, in combination with material parameters and boundary conditions, establishing a kinetic equation, and performing modal and dynamic response analysis. According to the method, the blade design and analysis efficiency is effectively improved, the structural strength and the vibration characteristic are guaranteed, and a novel propelling solution with economical efficiency and innovativeness is provided for Boeing aircrafts and other types of aircrafts.

This invention discloses a method for identifying dynamic loads on structures based on dynamic displacement inversion and motion control equations. The method includes: dividing the structure under test into several four-node inverse shell elements; deploying sensors at the centroid positions of the upper and lower surfaces of each element; reconstructing the displacement values ​​of each element node based on the collected strain data; predicting the displacement values ​​at any position of the structure under test using a high-resolution spatial domain reconstruction algorithm based on the reconstructed displacement values ​​of each element node; discretizing the fourth-order spatial deflection derivative of the displacement field of the structure under test using the finite difference method; approximating the second-order derivative of the strain data using the second-order central difference method to obtain the higher-order spatiotemporal deflection derivative; and establishing a model of the relationship between the dynamic displacement and load distribution of the structure under test by combining the motion control equations of the structure under test, thereby achieving dynamic load identification of the structure under test. Given the known geometry and material properties of the structure, this method can not only reconstruct the time history of the dynamic loads on the structure but also simultaneously identify the load application positions.

The invention belongs to the technical field of fan blade structure analysis, and particularly relates to a parametric modeling method and system for a composite fan blade section. According to the method, an airfoil profile is reconstructed with high precision by adopting an arc length parameterization and segmented cubic Hermite shape-preserving interpolation algorithm; extruding the two-dimensional contour along the spanwise direction based on an isoparametric mapping grid generation method to generate a three-dimensional shell unit grid; dividing unit sets of skin, web plates and paving layer transition areas; defining a layering sequence and optimizing the transition distribution of the thickness and the angle in the transition area; parametrically integrating the geometric model, the grid, the material attribute and the layering definition, and generating a finite element solver input file; and outputting a geometric comparison diagram, a layering distribution diagram and a grid quality evaluation diagram through a visualization system. According to the method, full-process parameterization integration of the fan blade section from geometric modeling to finite element analysis is achieved, the modeling precision and efficiency are improved, and reliable support is provided for optimization design of the blade structure.

The present invention discloses a safety calculation method for an attached aluminum alloy lifting platform, which simplifies the guide rails, vertical poles, diagonal rods, supporting trusses, etc. of the aluminum alloy platform into beam units, and simplifies the scaffolding into shell unit modeling, and first performs an overall check. Then, a three-dimensional model modeling analysis is performed on the wall-attached supports, which can greatly reduce the number of calculation grids, thereby reducing calculation time and memory. Beam units are suitable for slender structures in which one dimension is much larger than the other two dimensions, and only one-dimensional axes need to be considered in finite element modeling; shell units are suitable for structures in which dimensions in two directions are much larger than another dimension, and are considered as two-dimensional planes in finite element modeling. The present invention models part of the beam structure of the main frame of the aluminum alloy platform as a beam model in the finite element software, converts the load and adds it to the corresponding boundary, first performs an overall check, and then performs a three-dimensional model modeling analysis on the wall-attached supports, which can greatly reduce the amount of calculation and is also in line with actual conditions.

The invention relates to an air guide element (100) for a ventilation system of a vehicle headlight, comprising at least one component body (1) with at least one internal air guide channel, wherein the component body (1) is designed as a composite of at least two shell elements (11, 12). According to the invention, the shell elements (11, 12) are manufactured from a foamed plastic by thermoforming.

The application discloses a panel identification method and device of a three-dimensional finite element model. The method comprises the following steps: obtaining a three-dimensional finite element model; traversing the element edges of shell elements, identifying the panel boundary in the element edges according to a panel boundary judgment condition, and determining the shell elements constituting the panel; determining the nodes corresponding to the panel according to the corresponding relationship between the shell elements and the nodes and the corresponding relationship between the shell elements and the panel; determining the type of the panel according to the nodes corresponding to the panel, identifying the contour nodes of different types of panels, and the type of the panel comprises a planar panel and a curved panel; traversing the contour nodes, grouping the contour nodes according to a node grouping condition, and making each group of contour nodes correspond to the same panel edge of the panel. The application determines the contour nodes of the panel and the type of the panel by identifying the shell elements and the nodes included in the panel, and can identify all types of panels included in the three-dimensional finite element model.

The invention relates to a parametric modeling method for a plane truss of an end expansion support node, and is suitable for the field of steel structure design. The method comprises the following steps: generating a corresponding overall line unit model based on a structure type of a plane truss in combination with overall size parameters; on the basis of component size parameters of the side columns and the chord members and corresponding line segments of the overall line unit model, section feature points are determined, and then a section profile curve is generated; based on the section profile curves of the side columns and the chord members, generating shell unit models of the side columns and the chord members in combination with the corresponding line segments of the integral line unit model; determining contour feature points based on the component size parameters and the node size parameters of the support and the overall line unit model line segments corresponding to the support, and further generating a contour line of the support; based on the contour line of the support, a support web model and a support flange model are generated, and a support model is obtained; and obtaining an integral shell unit model of the plane truss based on the shell unit model of the side columns and the chord members and the supporting model.

The present application belongs to the technical field of engineering structure optimization design, and discloses a kind of topological optimization method and equipment of three-dimensional curved surface composite material thin shell structure, steps are as follows: S1, using conformal geometric mapping algorithm three-dimensional curved surface grid is mapped to the parameterization coordinate of two-dimensional plane parameter domain angle-preserving, obtain the mapping relationship of three-dimensional curved surface composite material thin shell structure from three-dimensional curved surface to two-dimensional plane;S2, construct shell element stiffness matrix of finite element grid;S3, in two-dimensional plane parameter domain, with the relative density of shell element and the direction of element as design variable, establish the topological optimization model of finite element grid based on conformal mapping;S4, based on moving asymptote method and topological optimization model to update design variable;S5, based on the design variable and mapping relationship of updated inversion mapping back original three-dimensional curved surface, thus obtain the three-dimensional configuration of optimal material distribution of three-dimensional curved surface composite material thin shell structure.The present application improves optimization efficiency.

Provided are a press forming analysis method, a press forming analysis device, and a press forming analysis program that can predict press forming loads in advance even for new part shapes and materials. [Solution] The press forming analysis method of the present invention is a press forming analysis method that uses the finite element method to predict press forming loads using a mold model 9 having an upper mold model 11 and a lower mold model 17 modeled with shell elements, and includes an elastic element-added lower mold model creation step S1 in which the lower structure 7 of the press device is modeled with elastic elements 15 and attached to the lower mold model 17 to create an elastic element-added lower mold model 13, an elastic coefficient determination step S3 in which the elastic coefficient to be given to the elastic elements 15 is determined, and a press forming load acquisition step S5 in which press forming analysis is performed using the mold model 9 including the elastic element-added lower mold model 13 modeled in the elastic element-added lower mold model creation step S1, and the press forming load is acquired.

The invention discloses a web bonding state determination method and device and a computer storage medium. The method comprises the following steps: constructing a shell unit model of the wind power blade to determine a load parameter of an external load acting on each position of a web of the wind power blade, and determining a risk position in each position according to the load parameter of each position and a preset load threshold value; constructing a three-dimensional entity model of each risk position according to the preset layering information of each risk position; and according to the three-dimensional entity model of each risk position, the web bonding state of each risk position is determined. According to the method, stress distribution nonuniformity is considered, a risk position is determined through a shell model, and a three-dimensional entity model of a local position is constructed, so that the calculated amount is reduced, and meanwhile, the accurate web bonding state is obtained.

The invention discloses a hyperelastic constitutive calculation method compatible with three-dimensional and shell elements, which comprises the following steps: establishing a unified theoretical framework of an elastic constitutive as a basis by strictly deducing a unified solution process of the hyperelastic constitutive, and representing stress and a consistent tangent stiffness matrix as a deformation gradient; a user only needs to provide a small number of expressions or parameters such as first two-order derivatives of a strain energy function about an invariant or a main tensile value, a unit dimension, a stress objective rate type and the like, and outputs stress and consistent tangent stiffness, so that the user input is minimized, and the user experience is improved. The successful implementation of the hyperelastic constitutive structure with different unit types, different stress objective rates and different strain energy forms under a unified solution system in a finite element is realized.

The invention discloses a virtual shell method for ship vibration forecast attached water calculation, which comprises the following steps of: establishing a virtual ship hull shell unit on a node of an original ship hull shell unit based on a whole ship finite element model; the grid size of the virtual hull shell unit is larger than that of the original hull shell unit; the virtual hull shell unit is used for a grid unit for carrying out attached water mass calculation. According to the method, the workload of attached water mass calculation can be greatly reduced, the calculation time is greatly shortened, calculation resources are saved, and the vibration forecasting precision is guaranteed.

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 provides a corrugated box finite element modeling method for simulating package falling, comprising the following steps: S1: determining equivalent elastic mechanics parameters of corrugated paperboard; S2: verifying whether the equivalent plate anisotropic elastic mechanics parameters are accurate, and if yes, entering S3, otherwise, returning to S1 until the equivalent plate anisotropic elastic mechanics parameters pass the verification; S3: establishing a paper box geometric model, decomposing the paper box into six surfaces of upper, lower, left, right, front and back, modeling each surface by adopting a shell element, and setting topology sharing; S4: respectively giving each surface of the paper box corresponding material properties; S5: dividing the paper box grid model by adopting a quadrilateral, and completing contact setting of the paper box and other PART, setting boundary conditions and load, and solving setting. The method solves the problem that the simulation calculation result of the package falling is not accurate and reliable due to the modeling error of the paper box by combining mechanical test and theoretical formula.

The invention relates to a thin-wall structure model generation method and device, engineering machinery and a medium, and relates to the technical field of engineering machinery. The model generation method comprises the following steps: discretizing a thin-wall structure into a plurality of shell units by utilizing a finite element analysis method, wherein each shell unit in the plurality of shell units comprises a plurality of nodes; dividing the first mass value of the thin-wall structure into a second mass value corresponding to each node in the plurality of nodes, and determining the translational inertia force of each shell unit according to the second mass value and the position vector of each node in the global coordinate system; dividing the first rotational inertia value of the thin-wall structure into a second rotational inertia value corresponding to each node, and determining the rotational inertia force of each shell unit according to the second rotational inertia value and the angular velocity vector and the angular acceleration vector of each node under the global coordinate system; and generating a dynamic model of the thin-wall structure according to the translation inertia force and the rotation inertia force.

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.

A press forming analysis method according to the present invention uses a finite element method, and predicts a press forming load using a die model 9 having an upper die model 11 and a lower die model 17 modeled by shell elements. The press forming analysis method comprises: an elastic body element-imparted lower die model creation step S1 in which a lower structure 7 of a press device is modeled by an elastic body element 15 and imparted to the lower die model 17 to create an elastic body element-imparted lower die model 13; an elastic coefficient determination step S3 of determining an elastic coefficient to be imparted to the elastic body element 15; and a press forming load acquisition step S5 of performing press forming analysis using the die model 9 including the elastic body element-imparted lower die model 13 modeled in the elastic body element-imparted lower die model creation step S1, to acquire the press forming load.