11 results about "Dynamic strength" patented technology

The invention belongs to the technical field of aviation hydraulic piping system testing, and particularly relates to an airplane hydraulic piping system fluid-structure interaction dynamic strength test platform and a test method thereof. The coupling effect of high-pressure pulsating fluid excitation and complex structure vibration excitation borne by the hydraulic piping system in the flight process of an aircraft is simulated in a high-fidelity mode, so that the dynamic strength weak link of the piping system is effectively exposed, and technical support is provided for optimization design and reliability verification of the hydraulic piping system. And efficient, safe and low-cost development of the aircraft hydraulic piping system is realized.

This invention discloses a design method for refractory high-entropy alloys, belonging to the technical field of compositional design of refractory high-entropy alloys. The design method includes the following steps: for refractory high-entropy alloys in the Nb-Ta-Hf-Zr-Mo-Ti-W system, establishing a compositional design method containing 10... ‑3 s ‑1 up to the 2000s ‑1 This invention presents a composition-performance dataset covering a strain rate range. Core physical features are extracted, and the dataset is expanded using Monte Carlo sampling after data cleaning. A random forest model is employed, with alloy composition and physical features as inputs and dynamic strength and fracture strain as outputs. The optimal model is selected through cross-validation, and the MeanUds' regulatory mechanism on performance is analyzed using SHAP value analysis. Target alloy compositions are then selected based on compositional design constraints. This invention achieves a synergistic improvement in the strength and quasi-static ductility of refractory high-entropy alloys.

The invention relates to a parachute canopy fabric numerical simulation method and a computer readable storage medium. The method comprises the steps that material parameters and historical states are initialized and read; updating an accumulated total strain tensor based on the strain increment and calculating a strain rate tensor; the principal direction modulus is evolved according to the accumulated total strain tensor, the material stiffness matrix is updated, and then the pure elastic stress increment is calculated; viscous damping stress is calculated in combination with the strain rate and the stiffness matrix, and a trial stress tensor is obtained after superposition and historical stress; performing wrinkle correction on the trial stress according to the strain state in the main direction, eliminating the stress in the compression direction and reducing the corresponding shear stress; calculating a dynamic strength threshold value by adopting a logarithmic strengthening model based on the strain rate and judging failure; and finally storing the updated state and outputting the stress tensor. A computer program is stored on the readable storage medium, the method can be implemented when the program is executed, and high-fidelity numerical simulation of the mechanical behavior of the canopy fabric is achieved.

The invention discloses an EGS surrounding rock thermal efficiency estimation method and system based on a dynamic strength criterion, and relates to the technical field of dry hot rock geothermal resource development, and the method comprises the steps: introducing a temperature correction term and a bedding direction coefficient based on a Nova-Zaninetti criterion, and building a dynamic strength equation; establishing a three-dimensional roadway model of the enhanced geothermal system based on excavation; constructing a heat transfer model of the enhanced geothermal system based on the unsteady heat conduction equation; based on the dynamic strength equation, a solid mechanical field model of the enhanced geothermal system is constructed; the heat transfer model and the solid mechanical field model are coupled into the three-dimensional roadway model, and a surrounding rock heat efficiency numerical model of the enhanced geothermal system is constructed; and estimating the thermal efficiency of the enhanced geothermal system based on the surrounding rock thermal efficiency numerical model. According to the invention, the technical problem of large deviation between the thermal efficiency estimation result and the actual thermal efficiency estimation result in the prior art is relieved.

This application provides a method for forced response analysis of an integral bladed disk (IBD), comprising: constructing a finite element model of an IBD sector; conducting disk-coupled resonance analysis of the finite element model to obtain the frequency, mode shape, and relative vibration stress of the IBD blades under one to multiple node diameters, and plotting disk-coupled resonance diagrams; determining the critical node diameter related to the number of rotor and stator blades; determining the frequency order and corresponding critical resonance speed by combining the plotted disk-coupled resonance diagrams and the critical node diameter; performing damping tests on the IBD blades to obtain the frequency order and corresponding modal damping ratios; establishing a full-ring model of the IBD rotor blades and the stator blades before and after them; conducting steady flow field analysis of the full-ring model to obtain steady results as the initial field conditions for unsteady flow field analysis; conducting unsteady flow field analysis to obtain the actual vibration stress of the IBD; and conducting dynamic strength reserve analysis to evaluate the dynamic strength reserve of the high-load IBD under the analysis conditions.

The application discloses a design method of a wing arm tilting mechanism of a tilt-rotor aircraft, and steps are as follows: combining a connecting rod mechanism principle, a tilting transition working condition rotor six force element and a tilting rudder torque threshold, transmission ratio design is completed; a distributed method and a topological optimization technology are adopted to obtain the best force transmission route and the optimal configuration of a motor support and an end frame support; a tilting transition and a peak torque working condition are taken as loads, and digital simulation and theoretical mechanics are combined to design static strength; a dynamics model is constructed based on vibration characteristics, a multi-rotor and a fixed-wing configuration wing arm vibration spectrum is taken as a load, and dynamic stress is superposed on static stress to design dynamic strength as a checking threshold. The application combines theoretical mechanics, vibration mechanics and digital simulation technology, provides a systematic design route, can realize high-G value resistance, lightweight, high stability and high reliability of the tilting mechanism design, guarantees reliable work of tilting, saves cost and shortens a development period.

The invention discloses an aircraft seat vibration reduction system and a design method thereof, and belongs to the technical field of aircraft structure dynamic strength. The system comprises two shock absorbers which are distributed left and right, and each shock absorber is composed of a shell, a spring piston rod system, a wear-resisting system, a movement connecting piece and a fastening screw. The spring piston rod system is contained in the shell and keeps a radial gap of 1-2 mm with the inner wall of the shell, a piston rod of the spring piston rod system is coaxial with the shell, and an upper spring and a lower spring are connected in parallel and pre-compressed. The design method comprises the following steps: determining a vibration isolation target frequency based on a seat joint PSD curve; calculating system design frequency and total rigidity; calculating single-spring rigidity according to the parallel structure and determining geometric parameters of the single-spring rigidity; the sizes of all parts are designed in a coordinated mode, and interference inspection is conducted; and finally manufacturing and installing. The system is compact in structure, adjustable in rigidity, high in vibration isolation rate and scientific in design method, vibration transmitted from an aircraft body to the seat can be effectively attenuated, and the problems that the vibration environment of the aircraft seat is difficult to predict, and later optimization is difficult are solved.

The invention provides a multi-working-condition strength verification method for an overhead guard assembly, and relates to the technical field of dynamic characteristic testing, and the method comprises the steps: collecting transient strain response signals of an overhead guard in a switching process from a static load to an impact load in real time through arranging piezoelectric dynamic strain sensor arrays at key parts of a stand column, a top beam and a base of the overhead guard assembly; and high-frequency and low-frequency components in the strain signals are extracted by using wavelet packet decomposition, dynamic stress wave propagation characteristics are analyzed based on an energy entropy principle, and a dynamic response transfer chain is further established. An accumulated damage value is calculated through a strain energy density criterion, and a dynamic strength evaluation system is constructed, so that dynamic stress distribution and a dynamic deformation field of the overhead guard under different impact load working conditions are accurately evaluated. Thus, the accuracy of dynamic strength verification of the overhead guard can be improved, the structural dynamic characteristics under the static load-impact load switching working condition can be comprehensively reflected, and the safety and reliability of the overhead guard under the complex working condition are ensured.

The invention belongs to the technical field of airplane dynamic strength design, and particularly relates to a dynamic boundary equivalent design method considering heat influence. The method comprises the following steps: constructing a finite element model of an overall structure containing a target structure, and calculating thermal stress distribution of the overall structure under a specified temperature load; calculating the low-order modal frequency and vibration mode of the overall structure caused by thermal stress; constructing an equivalent design initial model comprising a target structure and a peripheral structure; calculating a low-order modal frequency and a vibration mode of the target structure caused by thermal stress; optimizing the peripheral structure into a plurality of boundary support thin plates by taking the maximum constraint after the low-order modal frequency of the target structure as a target function, and forming an optimal topology model; calculating a low-order modal frequency and a vibration mode of the target structure caused by thermal stress; and by taking the low-order modal frequency and vibration mode closest of the target structure and the overall structure as an optimization target, optimizing the size parameters of each boundary support thin plate, and obtaining the dynamic boundary equivalent design parameters for the target structure.

The invention belongs to the field of airplane structure strength test, and particularly relates to a movable airfoil structure vibration superposition static load test device which comprises an integral frame, a static load system, a movable excitation platform, an excitation device and a movable airfoil test piece. The integral frame is used for supporting the static load system, the movable excitation platform, the excitation device and the movable airfoil test piece; the movable airfoil test piece is horizontally arranged, the static load system is connected with the movable airfoil test piece, and the static load system can perform distributed static load low-rigidity loading on the movable airfoil test piece through an air bag; the two groups of excitation devices are arranged on the movable excitation platform side by side; through collaborative innovation of the movable excitation platform, the distributed static load system and the high-rigidity frame, remarkable advantages are formed in the aspects of test efficiency, working condition simulation authenticity, data precision, universality and the like, and efficient and reliable test equipment is provided for ground dynamic strength verification of the movable airfoil of the civil aircraft.

The invention discloses a composite material with high density, high strength and excellent dynamic mechanical properties, the chemical formula of the composite material is Wx (FeaNibCrcVdAle) y, x and y correspond to the mass percentage of W and the mass percentage of FeaNibCrcVdAle; the method comprises the following steps: 1, selecting iron, nickel, chromium, vanadium and aluminum metal raw materials, and preparing high-entropy alloy spherical powder by adopting a vacuum suspension smelting process and a vacuum gas atomization process; secondly, the high-entropy alloy spherical powder and tungsten powder are subjected to ball milling and mixed to be uniform, and mixed powder is obtained; and 3, carrying out hot pressed sintering on the mixed powder. According to the composite material, high-density tungsten is selected as a matrix component, a high-entropy alloy component with ultrahigh dynamic strength and excellent strain localization capability is selected as a composite phase, and the composite material with high density, high strength and excellent dynamic mechanical property is obtained; the preparation method is simple and convenient in process, controllable in material component, high in material density and suitable for being used as the armor-piercing bullet core material.