7 results about "Effective stiffness" patented technology

The invention discloses a spaceflight structure strength analysis method based on a multi-physics field, which comprises the following steps: establishing a parameterized finite element model integrated with a friction heat generation effect by acquiring in-orbit temperature time sequence data and material creep characteristic parameters, and simulating inelastic strain accumulation of a structure under a thermal cycle load; a nonlinear damage model considering a creep-fatigue interaction effect is adopted to calculate an accumulated damage degree, an effective stiffness matrix is constructed to deduce a structure inherent frequency drift distance and a shape retention capability parameter, and finally, through a safety margin evaluation algorithm, the effective strength of a material and the maximum equivalent stress of the structure are dynamically compared, so that the performance of the material is evaluated. And accurate prediction of quantitative residual strength and safe service life is realized. According to the method, the technical problems that the local thermal coupling effect is not depicted enough and the creep fatigue nonlinear interaction effect is ignored are solved, and the precision and reliability of on-orbit performance degradation prediction of the spaceflight flexible structure are remarkably improved.

The invention provides an aircraft composite material dot matrix interlayer energy absorption structure and a performance prediction method thereof, and belongs to the technical field of composite materials. A stretching-dominated octagonal truss dot matrix is used as a basic dot matrix structure, stretching-dominated and bending-dominated body-centered cubic dot matrixes and simple cubic dot mechanical characteristics are fused to strengthen mechanical properties, a new mixed dot matrix structure is formed, and an optimal arrangement strategy of the dot matrix structure is established and inspired by a bionic bone microstructure. The characteristics of the two lattice structures are combined, the mechanical properties of the sandwich structure are effectively improved, the sandwich structure has higher peak load, average load and specific energy absorption and more stable crushing force efficiency, a prediction model of the effective rigidity and relative density of the two-phase lattice is established, the customized mechanical properties are effectively achieved, and the application range of the sandwich structure is widened. And the application of the lattice sandwich structure in an aircraft structure is widened.

This invention discloses a method for determining the nonlinear contact position between the drill string and the wellbore. The connection point between two adjacent elements is considered a node. The finite element dynamic equations of the drill string at the current moment are transformed into a relationship between the effective stiffness matrix of the drill string, the displacement matrices of all nodes of the drill string, and the effective load matrix. The method divides the equations into blocks according to the two-element, three-node relationship. Matrix operations are performed on each sub-expression to obtain the radial displacement matrix expression for each intermediate node. If the radial displacement is greater than the gap between the wellbore and the drill string, the radial displacement of the node is set to the gap value, and matrix multiplication is performed again to obtain a new effective load sub-matrix. This process is repeated to calculate the radial displacement of all nodes until all are within the gap between the wellbore and the drill string. The radial displacement of the drill string at the current moment is then combined to obtain the node displacements at all times. Finally, it is determined whether the radial displacements of all nodes at all times are equal to the gap between the wellbore and the drill string to determine the nonlinear contact position between the drill string and the wellbore.

The present application relates to a kind of methods for reducing the internal defects of composite winding products, the present application can realize the accurate control of winding product size by outer mold, control winding tension before injecting glue, so as to provide driving force for inner resin and inhibit its defect generation;During the injection process, the resin matched with winding resin is injected into the winding product by driving pressure, the driving force of injection cooperates with winding tension, drives away bubble from inside and outside at the same time, balances the distribution of resin, solves the problems of high porosity of fiber winding product, uneven resin distribution and low interlaminar performance, improves the integrity, density and uniformity of winding product.The present application effectively reduces the crack initiation source of product, improves the stress transfer ability of product interior, improves the load-carrying capacity of such components, avoids the sharp reduction of effective stiffness caused by the invasion of pressure medium due to the mutual penetration of internal pores, improves the reliability of such products.

The application relates to a spring motion behavior simulation method and system. The spring motion behavior simulation method comprises the following steps: acquiring geometric defect feature data and assembly deviation feature data of a spring; constructing a spring digital model based on the geometric defect feature data and the assembly deviation feature data; predicting local coil contact and buckling deformation of the spring in the spring motion process based on the spring digital model, and quantifying nonlinear friction damping and dynamic effective stiffness variation of the spring. The application can more truly simulate the non-ideal behavior of the spring under the action of complex loads by integrating the actually existing geometric defects and assembly deviations into the digital model, improves the accuracy of design verification, and provides a reliable basis for performance optimization of a vehicle suspension system.

The application discloses a simulation method for simulating offshore wind power tower cylinder pile foundation soil pressure by using spring stiffness, and comprises the following steps: obtaining pile foundation parameters, soil layer parameters and a cyclic load sequence; constructing a spring node pile-soil system and initializing displacement; applying the load sequence, extracting pile body deformation mode progressive transition characteristics, redistributing node spring stiffness to obtain redistributed stiffness; based on characteristic tracking, rotating center dynamic migration area is obtained and bidirectional stress history correction is carried out to obtain migration area correction stiffness; based on displacement, the evolution state of the gap between shallow layer nodes is evaluated and transient stiffness conversion is performed to obtain the effective stiffness of the gap area; and the above stiffness is fused to solve the updated displacement and soil pressure distribution. The application realizes adaptive resistance correction and multi-mechanism superposition evolution high-precision feedback with load evolution, and improves the robustness and fidelity of the analysis.

The invention relates to a design method of a blade middle surface layer-propeller hub integrated metal embedded composite material propeller, which comprises the following steps: constructing a blade middle surface layer-propeller hub integrated metal embedded composite material propeller integral structure, the structure comprises an integrated high-rigidity area made of metal and a carbon fiber composite material layer wrapping the integrated high-rigidity area. The propeller is divided into a limited number of areas with similar shapes in the radial direction, and the areas are segmented and discretized into fiber metal laminated variable cross-section beams with similar limited section widths; based on a classic laminated plate theory and metal plastic mechanics, acquiring a stiffness parameter of the fiber metal laminated variable cross-section beam through a multi-scale hybrid analysis method; a series spring model is adopted, the variable cross-section beams in the similar areas of the same shape are connected in series and stacked, and then stacking results of all the areas are combined to obtain the overall effective rigidity of the propeller; and according to the overall effective rigidity result, the laying sequence and interlayer ratio of the metal layers and the composite material layers are designed.