140 results about "Shell element" patented technology

Ship structural ultimate bearing analysis and design research is involved. A method for implementing ultimate strength analysis of plate frame structure based on isogeometric analysis includes the following steps: according to the plate frame structure, constructing an IGA model, wherein the IGA model comprises several plane shell elements; carrying out a coordinate transformation on the plane shell elements; carrying out a weak coupling on boundaries of transformed plane shell elements by Nitsche method and carrying out a mesh refinement; setting material properties, loads and boundary conditions of refined plane shell elements, and constructing a nonlinear equation according to setting results; and solving the nonlinear equation by Newton-Raphson iteration method, and carrying out a simulation analysis by NX software to obtain an ultimate strength of the plate frame structure.

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 belongs to the technical field of gear transmission, and discloses a dynamic modeling method of a flexible bevel gear system considering meshing point change, which is used for analyzing vibration response and dynamic stress response characteristic laws of the bevel gear system in a traveling wave resonance state. And further analyzing the traveling wave resonance phenomenon of the spiral bevel gear system in the aero-engine accessory casing. A three-dimensional shell unit and a beam unit are adopted to establish a bevel gear pair finite element entity model. A dynamic model of the flexible bevel gear system considering meshing point changes is established by adopting a substructure modal synthesis method and a rotation modal projection method. The reliability of the provided model is verified through a finite element entity model and an experimental test result. On the basis, dynamic response and vibration stress experiment tests are combined, and the traveling wave resonance phenomenon of the bevel gear system is researched. The research result of the provided model has theoretical significance on design and fault monitoring of the aero-engine bevel gear system.

The invention discloses a high-order and low-order mixed inverse finite element deformation reconstruction method based on distributed strain, and belongs to the technical field of finite element deformation reconstruction, and the method comprises the steps: constructing a high-order shell unit in combination with a planar film unit and a plate bending unit; and constructing a high-order inverse shell unit of a complex continuous strain area, constructing a step type inverse shell unit of a cross rib / rib area, and performing boundary transition processing to complete deformation reconstruction. According to the method, the inverse shell unit is constructed in combination with the diaphragm plate unit, and the ribs and discontinuous areas are emphatically processed, so that inverse finite element deformation reconstruction is effectively realized; the boundary is subjected to transition processing, so that the efficiency of inverse finite element deformation reconstruction is improved; and technical support is provided for safety evaluation, failure prevention and control, performance control and even optimization design of the aviation composite material structure.

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 invention relates to the technical field of weld joint dynamic modeling, in particular to a thin-wall shell weld joint dynamic modeling method based on a common shell unit, which comprises the following steps of: S1, dispersing the middle surface of a welding part by a global shell grid, and simulating a weld joint by using a CSE instead of a rigid connection unit; s2, simplifying the modeling process of the CSE by adopting a grid common node processing method; s3, constructing an interface shell unit to replace part of GSM on the two sides of the welding area, and achieving the grid consistency requirement; s4, the CSE welding seam modeling method is applied to welding of the thin-wall shell for dynamic simulation analysis; and S5, performing result verification and adjustment on the data obtained by simulation in the step S4. According to the method, the ISE unit is introduced to meet the grid consistency requirement of the non-matched connection interface; building a weld joint dynamic model based on a CSE and RE modeling method, and carrying out dynamic simulation analysis and experimental research; the problem that the finite element analysis accuracy is affected due to the fact that an existing connecting unit cannot accurately simulate the real characteristics of weld joints is solved.

The invention belongs to the field of shell unit design, and relates to a shell unit design method for reliability research of an aviation thin-shell structure, which comprises the following steps of: discretizing the aviation thin-shell structure, and endowing each unit with determined geometric dimension and material parameters to form a normal distribution or random distribution probability model; and forming a random finite element model in cooperation with the element stiffness matrix, and performing finite element stiffness calculation of probability random distribution. A probability random distribution condition is introduced on the basis of a stiffness analytical expression of each traditional unit, so that the influence of uncertain factors in process manufacturing can be considered in simulation analysis of the aviation plate shell structure, and the adverse influence of a traditional safety coefficient method on structural design is avoided; meanwhile, the tedious process that a large number of input files need to be prepared when a deterministic analysis unit is used for structural reliability analysis is reduced, and the structural reliability design iteration process can be accelerated.

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 present invention provides a method for classification and identification of gastropods based on shell element analysis, including: S1. Using a laser ablation inductively coupled plasma mass spectrometer to measure the contents of 55 trace elements in gastropod shells; S2. Screening out 24 trace elements with significant differences based on one-way variance analysis; S3. Performing stepwise linear discriminant analysis based on the 24 trace elements, and classifying them using a random forest classification method. In the S‑LDA model, the contents of the 24 trace elements are gradually input as variables, and a discriminant function is established based on the Wilkes λ value standard, achieving a correct discrimination rate of 92.7% for species identification, and a random forest model based on the contents of the 24 trace elements achieves a correct discrimination rate of 97.0%, which is applicable to the classification and identification of gastropods.

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.

A fastening device for a shell element which is flat at least in portions and which has a support element and a pressing element, wherein the pressing element is wedge-shaped and the support element is designed correspondingly to the wedge-shaped pressing element, wherein at least one fastener is provided, by way of which the pressing element is releasably fixed to the support element such that the shell element which is flat at least in portions is force-fittingly and form-fittingly fixable between the pressing element and the support element.

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 provides an aluminum alloy engine hood design method which comprises the following steps: S10, performing simulation calculation on five analysis working conditions, namely a rear edge beam bending working condition, a side edge beam bending working condition, a corner point bending working condition, a torsion working condition and a lateral bending working condition, of an inner plate of an aluminum alloy engine hood to obtain rigidity values of the five analysis working conditions; s20, establishing an initial model of the inner plate based on design boundary conditions, wherein the middle part of the initial model of the inner plate is completely filled with a shell unit; s30, establishing a topological optimization scheme for the initial model of the inner plate to obtain a topological model; s40, after the topological model is interpreted, an initial model with the size optimized is obtained, a size optimization scheme is established, size optimization is conducted, and a final optimized structure model is obtained; and S50, performing rigidity calculation on the final optimization structure model to obtain rigidity values of the optimized inner plate under the five analysis working conditions.

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.

Embodiments of the present application provide a composite wallboard high-energy soft impact simulation analysis modeling method, device, equipment and medium, comprising the following steps: constructing a finite element model of a composite wallboard, simulating the intralayer damage of the wallboard by shell elements or continuous shell elements, and simulating the interlayer damage of the wallboard by cohesive elements; constructing an impact model, the impact model comprising a solid rubber soft buffer model and a rigid plate, the rubber soft buffer model being an Ogden hyperelastic constitutive model; constructing a failure criterion for the finite element model, the failure criterion being used to judge the damage initiation and evolution process of each failure mode; setting constraints for the finite element model; assigning the impact model with initial conditions for impact simulation; performing explicit dynamics analysis by a solver to obtain damage analysis results of the wallboard under impact. The technical problems of high cost and low prediction accuracy in the prior art can be solved.

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.