145 results about "Stiffness coefficient" patented technology

The invention belongs to the technical field of calculation of horizontal bearing capacity of foundations, and particularly discloses and provides an accurate calculation method for horizontal bearing capacity of an offshore wind power foundation, which comprises the following steps: integrating wave spectrum, wind regime, tide and soil mass parameters to form a multi-dimensional data set; a three-dimensional pile-soil model is constructed, and wave force and wind load are coupled; calculating a stiffness coefficient and identifying a pile body type in combination with a length-diameter ratio; quantifying an environment deviation compensation coefficient according to the pile body type; after the initial horizontal bearing capacity is calculated, the bearing capacity failure critical state is judged based on real-time displacement monitoring data, and if the critical state is reached, the initial bearing capacity is corrected through linear weighting of the displacement deviation compensation coefficient and the environment deviation compensation coefficient. According to the method, the time-varying environment load is dynamically coupled, the pile-soil interaction is finely simulated, a rigidity self-adaptive grading mechanism and a double compensation feedback system are established, and the calculation precision and the real-time early warning capability of the horizontal bearing capacity in the complex marine environment are remarkably improved.

The application discloses a kind of centrifugal pump shafting critical speed calculation method, including the finite element calculation of radial roller bearing and thrust roller bearing stiffness coefficient curve, the prestressed modal analysis and critical speed calculation of centrifugal pump shafting considering different bearing stiffness coefficient.The setting of constraint condition of this method is in line with actual situation, which can realize the accurate calculation of centrifugal pump shafting critical speed, and help to improve the reliability of safety check of centrifugal pump shafting in design stage, at the same time, the calculation steps are simple, and the engineering application range is wide.

The invention relates to the technical field of composite material structure dynamics analysis, and provides a method and system for predicting the inherent frequency of a three-phase functionally graded composite material conical plate, and the method comprises the steps: employing an improved Halpin-Tsai model to calculate the equivalent parameters of a GPL-containing two-phase composite matrix, solving the equivalent parameters of a three-phase composite layer, and calculating the inherent frequency of the three-phase composite material conical plate. The method comprises the following steps: constructing a nonlinear geometrical relationship between a displacement field and a strain field, calculating a stiffness coefficient of each layer, constructing kinetic energy of the three-phase composite material conical plate, calculating an energy coefficient according to the stiffness coefficient of each layer, constructing potential energy of the conical plate according to the energy coefficient, and constructing a modal displacement function by adopting a Chebyshev polynomial and a boundary function. And establishing a characteristic equation based on a minimum potential energy principle and solving to obtain the inherent frequency of the three-phase composite material conical plate. According to the method, efficient calculation of the inherent frequency of the three-phase composite material conical plate is achieved, and the reliability and engineering application value of structural dynamics analysis are remarkably improved.

The invention provides a die cutting equipment error optimization method and system based on group collaboration, and relates to the technical field of die cutting machines, and the method comprises the steps: carrying out the spectrum analysis of a frequency characteristic curve of each piece of die cutting equipment, so as to divide an initial interference group; establishing a virtual spring damping network in the initial interference group, regarding each die cutting device in the initial interference group as a mass point, and determining a spring stiffness coefficient and a damping coefficient according to an actual distance between adjacent mass points; determining vibration mode characteristics of each die cutting device according to the spring stiffness coefficient and the damping coefficient, and converting a control signal generated according to the vibration mode characteristics into a parameter adjusting variable by using a preset control algorithm; and determining a vibration coupling relationship according to the collected vibration energy data of the initial interference group after the initial processing parameters are adjusted according to the parameter adjusting quantity, and determining an optimal production takt and a parameter compensation value according to the vibration coupling relationship. The technical problem that in the prior art, due to vibration coupling of a die cutting equipment group, the machining error cooperative control difficulty is large is solved.

The invention discloses a foundation pit supporting structure deformation and internal force calculation method. In the calculation method, an out-pit constraint stiffness matrix is introduced as a calculation factor, and a stiffness coefficient is iteratively calculated; the calculation method comprises the following steps: S1, constructing a foundation pit supporting structure calculation model; s2, a displacement-load total balance equation of the supporting structure under the undetermined supporting working condition of the foundation pit is determined; s3, a servo support is installed, prestress is loaded, a constraint stiffness matrix is introduced, a stiffness coefficient is calculated in an iterative mode, a displacement-load total balance equation of the supporting structure is established step by step, and the deformation condition of the supporting structure is analyzed and calculated; s4-5, the steps S2 to S3 are repeated until installation of all servo supports and prestress loading are completed, and displacement and internal force of the supporting structure are calculated; and S6, the foundation pit continues to be excavated to the pit bottom, deformation and internal force under all working conditions are calculated, and regulation and control calculation can be conducted in the process. By means of the calculation method, accurate calculation of deformation and internal force of the foundation pit supporting structure under the servo supporting effect can be achieved.

The present application relates to a robust adaptive variable admittance control method based on different intentions in a feature space. The method includes: using the kinematic and dynamic models of the manipulator to determine the mapping relationship between the actual contact force and the virtual contact force; determining the adaptive stiffness coefficient based on the actual contact force change, and determining the robust adaptive virtual damping coefficient based on the direct intention based on the virtual motion speed of the feature point; adjusting the robust adaptive virtual damping coefficient based on the contact force expected by the robot, and determining the admittance control virtual damping coefficient based on direct and indirect intentions; determining the robust adaptive variable admittance control based on human intention in the feature space based on the mapping relationship, the adaptive stiffness coefficient and the admittance control virtual damping coefficient; determining the robot image visual servoing control law based on the real-time image feature points and the expected feature points, obtaining the real-time joint velocity of the manipulator, and controlling the manipulator movement.

The invention discloses an equivalent pile length calculation method for long and short piles of a foundation pit based on a non-limit state, and relates to the field of equivalent pile length calculation, the equivalent pile length calculation method for the long and short piles of the foundation pit based on the non-limit state comprises the following steps: S1, acquiring parameters, and presetting a standard, principle and scheme set; s2, matching the long parameter with the scheme set, and arranging a displacement meter and a strain meter; s3, collecting data through a displacement meter and a strain meter, and forming effective mechanical response data; s4, establishing a stiffness load displacement equivalent length calculation model; s5, the rigidity coefficient and the load sharing proportion are calculated, and an equivalent pile length initial value is obtained through reverse deduction; and S6, the equivalent pile length initial value is adjusted, and a foundation pit long and short pile equivalent pile length calculation report is generated. According to the method, engineering suitability calculation of the equivalent pile length in a non-limit state is achieved through a non-limit state guided double-equivalent logic driven equivalent pile length calculation system for the long and short piles of the foundation pit, and the one-sided core pain point of single equivalent logic is avoided.

The invention discloses a method for calculating broadband consistent damping force in time-domain dynamic analysis, which comprises the following steps of: constructing a finite element model of a hydroelectric plant, endowing the model with material attributes, and then obtaining an initial stiffness matrix of the hydroelectric plant by adopting a finite element method; idealizing the finite element model as a main spring, and connecting a plurality of combined elements consisting of sticky kettles and springs in parallel to form an idealized model; according to the initial stiffness matrix, the dynamic stiffness model of the combined element and a damping ratio in time domain dynamic analysis, calculating a stiffness coefficient of each combined element by adopting a least square method; when the dominant frequency of the combined element is uniformly distributed in the broadband range, calculating the viscosity coefficient of the combined element according to the dominant frequency of the combined element and the target damping ratio; and according to the rigidity coefficient and the viscosity coefficient, a time domain damping force model is adopted to calculate the consistent damping force of the hydroelectric plant in the broadband range.

The invention discloses an active vibration absorber control strategy for vibration at the tail end of a flexible arm, and relates to the technical field of mechanical arm control, and the active vibration absorber control strategy comprises the following steps: building a three-dimensional model for a two-degree-of-freedom flexible mechanical arm, describing the joint flexibility of a system by using a linear spring, and representing the rigidity coefficient of a flexible joint by using the elastic coefficient of the linear spring; fuzzy RBF adaptive PID control is trained in combination with a real object, the identification precision of the model is improved, and vibration suppression is realized; in the fuzzy control, input variables are fuzzified by simulating the thinking mode of human beings, reasoning is carried out in combination with expert experience rules, and finally a system of an accurate dynamic model is established. According to the control strategy, the limitation of a traditional control technology based on a model during control is reduced, dynamic hysteresis nonlinearity generated in actual work is effectively corrected, the control precision is improved, fuzzy rule parameters are adjusted through modal analysis in combination with system characteristics, and the control precision is improved. Therefore, the vibration suppression force synthesis in different scenes is more accurate, and the vibration suppression effect is better.

The present application belongs to the field of mechanics, and particularly relates to a method for eliminating error of a quasi-static compression mechanics experiment system. By using a constant pressure or a constant loading speed of a pressure head on a testing machine to perform quasi-static uniaxial compression on a test piece at room temperature, and taking two test pieces of different heights, the relationship between the system stiffness, the force and deformation of the system pressure head can be obtained, so as to obtain two corresponding force-time curves and displacement-time curves. By combining the two equations and eliminating the unknown Young's modulus E, the stiffness coefficient of the test system can be obtained, and the displacement-time curve of the pressure head can be obtained. Subsequently, the Young's modulus E can be inversely solved. The present application corrects the error of the mechanics experiment by defining the system stiffness coefficient, so as to realize a higher precision of the Young's modulus E and improve the accuracy of the quasi-static mechanics experiment.

The present disclosure provides a Timoshenko beam model equivalent method and system of a corrugated steel plate support structure, and relates to the technical field of stress analysis of a corrugated steel plate support structure, comprising: solving the stiffness coefficients of the corrugated steel plate in a local coordinate system, including tensile stiffness, bending stiffness and shear stiffness; solving the equivalent stiffness coefficients of the orthotropic corrugated steel plate in a global coordinate system, including equivalent tensile stiffness, equivalent bending stiffness and equivalent shear stiffness; solving the equivalent section bending stiffness of the corrugated steel support structure; solving the equivalent section shear stiffness of the corrugated steel support structure; and equivalent the corrugated steel support structure to a Timoshenko beam model. The present disclosure can realize the rapid equivalent of the corrugated steel plate support structure to a Timoshenko beam model.

The application provides a method for determining the longitudinal wave velocity after fluid replacement in an anisotropic medium and related equipment. The method comprises the following steps: determining an average bulk modulus based on a matrix bulk modulus; determining a first bulk modulus when the medium contains fluid based on first property data; determining a second bulk modulus when the medium does not contain fluid based on the first property data, the matrix bulk modulus, the average bulk modulus and the first bulk modulus; determining a second vertical stiffness coefficient when the medium does not contain fluid based on the first property data, the average bulk modulus, the first bulk modulus and the second bulk modulus; obtaining second property data of each predetermined replacement fluid; and determining the longitudinal wave velocity after the fluid in the medium is replaced by the predetermined replacement fluid based on the first property data, the average bulk modulus, the second bulk modulus, the second vertical stiffness coefficient and the second property data. The technical problem that the longitudinal wave velocity determined after fluid replacement in an anisotropic medium is not accurate in the prior art is solved.

The invention discloses a numerical control milling and boring machine machining precision control method and a numerical control milling and boring machine machining precision management system, and relates to the technical field of milling and boring machine precision control. Calculating to obtain a comprehensive error predicted value delta pred by combining the square sum of the delta z and the sum value of the cutting force deformation delta form and the thermal deformation error delta thermal at the same time; then through the synchronously-arranged closed-loop feedback adjustment on the rigidity coefficient, the machining precision of the milling and boring machine can be better guaranteed, the machining precision of the milling and boring machine is adjusted in order and within a reasonable range in combination with the real-time situation monitored on site, and excessive adjustment is avoided; and meanwhile, different conditions after adjustment can be analyzed again, and more refined adjustment and attack control can be carried out.

The invention discloses a method for measuring a damping coefficient of a vehicle damper based on inertial sensing and visual tracking. The method comprises the following steps: S10, acquiring geometric quantities and inherent characteristics of a vehicle; angular velocities and angular accelerations generated when the vehicle moves in all directions are obtained; s20, calculating the vertical load of each suspension according to the data obtained in the step S10; s30, obtaining the internal force of a suspension spring damping model according to the suspension vertical load, the spring mass, the inherent geometrical relationship and the spring stiffness coefficient; and S40, judging whether the data volume is sufficient or not, if so, outputting a damper damping characteristic graph, and if not, returning to the step S10. The method can directly reflect the direct relation between the performance of the shock absorber and the motion characteristics of the vehicle.

The invention relates to a horizontal rotation vibration suppression method for a wind turbine blade hoisting system. The method comprises the following steps: acquiring basic parameters of a blade hoisting system; the inherent frequency of horizontal rotation of the main structure is obtained; at least two tuned mass dampers are arranged on the blade hoisting system to form the blade hoisting system with multiple tuned mass dampers; calculating a dynamic matrix equation of the blade hoisting system provided with the multi-tuned mass damper; calculating a response equation of horizontal rotation of the main structure; and calculating parameters of each tuned mass damper according to the response equation, and optimizing the parameters to obtain the vibration suppression blade hoisting system with the tuned mass damper with the optimal parameters. According to the method, the parameters of the mass damper are optimized by considering the installation position and the parameters of the mass damper and the response equation of horizontal rotation of the main structure, the optimal rigidity coefficient and the optimal damping coefficient are obtained, and therefore the optimized multi-tuned mass damper system is obtained, and the vibration suppression effect is better.

The application relates to the technical field of aero-engine structural design, in particular to a dynamic modeling method of a non-uniformly pre-tightened circular-arc end-tooth connected rotor, which comprises the following steps: establishing a whole-circle three-dimensional model and a finite element simulation model of a short bolt connected circular-arc end-tooth structure, setting a contact interface and a boundary condition, applying a working load, applying a circumferential non-uniform pre-tightening force to the bolt, calculating the stiffness of the end-tooth structure, establishing a beam element dynamic model of a convex-tooth side rotor and a concave-tooth side rotor, superimposing the local connection stiffness of the end-tooth structure and the rotor element stiffness, and assembling a whole dynamic model of the rotor system. The application can consider the actual situation of circumferential non-uniform relaxation of the circular-arc end-tooth pre-tightening force, multiple bolt assemblies can apply circumferential non-uniform pre-tightening force, only the connection stiffness coefficient of the end-tooth structure needs to be calculated, and the mass and rotational inertia characteristics of the end-tooth structure and the rotor non-continuous structure characteristics can be more accurately simulated.

The application provides a robot variable stiffness control method and device and a storage medium, and relates to the technical field of robots. The method comprises the following steps: acquiring actual position parameters and actual speed parameters of each joint in a robot; performing position and speed control on each joint based on a proportional integral differential (PID) controller according to the actual position parameters and actual speed parameters of each joint and a planned control track, wherein the PID controller comprises a proportional differential (PD) controller for performing position control on each joint and a proportional integral (PI) controller for performing speed control on each joint, the PD controller and the PI controller are in communication connection with a current controller, the application example can simplify control logic, the variable stiffness control of the robot can be realized without designing an impedance control system model, and in the control process, the oscillation phenomenon caused by improper design of inertia, damping and stiffness coefficient can be avoided, and the control effect can be effectively improved.

The present application relates to rock mass identification and early warning technical field, especially point to a kind of based on double index's toppling type dangerous rock mass identification method and device.Method includes: obtaining the rock bridge length of the toppling type dangerous rock mass to be identified, rock bridge stiffness coefficient, rock mass quality, friction coefficient on structural plane and effective normal stress;Based on calculating damping ratio and inherent vibration frequency;Based on inherent vibration frequency, damping ratio and rock mass quality, calculate rock bridge strength;Based on rock bridge strength, inherent vibration frequency and damping ratio, calculate the dynamic safety factor;Based on inherent vibration frequency and damping ratio, calculate weak stable dynamic safety factor;Based on dynamic safety factor and weak stable dynamic safety factor, according to preset identification rule, toppling type dangerous rock mass is identified, and identification result is obtained.The present application realizes the rapid damage identification of toppling type dangerous rock mass.

This invention discloses a robust design method for technical parameters of passive suspension systems aimed at performance optimization. It can robustly design two types of suspension system parameters—stiffness coefficient and damping coefficient—to cope with changes in vehicle weight. Specifically, the method constructs a four-wheel vehicle passive suspension system model and uses an improved Harris-Eagle optimization algorithm to search for the suspension stiffness coefficient and damping coefficient under varying vehicle weight conditions, thereby ensuring a balanced balance between vehicle ride smoothness and handling stability. This invention is a technical parameter design method for four-wheel vehicle passive suspension systems that does not rely on trial and error by technicians to optimize the technical parameters of the passive suspension system. More importantly, this invention considers the uncertainty of vehicle weight during actual driving; the designed parameters are optimal under different vehicle weight variations, exhibiting a high degree of robustness.

The invention belongs to the field of structure optimization design, and particularly discloses a topological optimization method and system for accurately and efficiently regulating and controlling the deformation characteristic of a structure, and the method comprises the steps: carrying out the finite element mesh generation of a to-be-optimized structure with the spring deformation characteristic, and defining a design variable corresponding to a mesh; determining the total strain energy constraint of the structure according to the stiffness coefficient and the maximum deformation of the spring, and establishing a first topological optimization model by taking the minimization of the total volume of the structure as a target; performing topological optimization based on the first topological optimization model to obtain a structural configuration and a total volume thereof; setting an upper limit of a structure total volume constraint according to the total volume, constructing the structure total volume constraint, and meanwhile, continuously using the structure total strain energy constraint of the first topological optimization model to establish a second topological optimization model by taking a p norm of minimizing an external force local deformation error as a target; and carrying out topological optimization based on the second topological optimization model to obtain a final structure configuration. The system is high in universality, diversified in function, accurate and efficient.

The invention discloses a rigidity prediction method of a carbon nano tube reinforced composite material laminated plate, a geometric accurate two-dimensional beam section modeling method is adopted to perform structural modeling on a carbon nano tube composite material beam, and the method can perform structural modeling on a thin beam under any boundary condition and any deformation, including large deformation displacement and section warping. And obtaining a 6 * 6 section stiffness matrix of the composite material beam, wherein the matrix elements comprise stretching, shearing, torsion and corresponding coupling stiffness coefficients. The method is suitable for predicting the rigidity of the carbon nanotube reinforced composite material laminated plate under the conditions of small deformation, medium deformation and large deformation (namely any deformation).

The application belongs to the technical field of foundation horizontal bearing capacity calculation, and specifically discloses a kind of offshore wind power foundation horizontal bearing capacity accurate calculation method, the method comprises: integrating wave spectrum, wind condition, tide and soil parameters to form multidimensional data set;Three-dimensional pile soil model is constructed and wave force and wind load are coupled;Stiffness coefficient is calculated and combined with length-diameter ratio to identify pile type;According to the type of pile, the environmental deviation compensation coefficient is quantified;After calculating the preliminary horizontal bearing capacity, the bearing capacity failure critical state is judged based on real-time displacement monitoring data, if the critical state is reached, the preliminary bearing capacity is modified by linear weighting of displacement deviation compensation coefficient and environmental deviation compensation coefficient.The application dynamically couples time-varying environmental load, simulates the interaction between pile and soil in detail, establishes a stiffness self-adaptive grading mechanism and a double compensation feedback system, significantly improving the accuracy and real-time warning capability of horizontal bearing capacity calculation in complex marine environment.

The present application relates to gear machining technical field, especially a kind of variable tooth thickness modification machining method for double lead worm gear and worm, including the wave form distortion rate of idle cutting force of hobbing cutter and torsional stiffness coefficient;Real-time monitoring cutting force wave form distortion rate and tool torsional deformation, calculate disturbance intensity index to divide disturbance level and set detection opportunity;Through the tooth thickness curve of actual measurement, tooth thickness change rate coefficient is obtained to judge machining quality;The tooth thickness deviation curve of unqualified tooth groove is analyzed to determine the dominant interference type, and the spindle speed or tool pose is regulated based on disturbance level;The control effect is verified by attenuation coefficient;When not up to standard, attenuation difference is used to optimize control coefficient;Finally, the overall quality of worm is evaluated by the consistency coefficient of tooth thickness change rate of each tooth groove of full tooth surface.The present application solves the problem that the full tooth surface consistency of formed worm is low due to the resonance and deformation disturbance of asymmetric characteristics of hobbing cutter in variable tooth thickness worm machining.

The invention discloses a design method of a vibration transmission sheet of thin kidney-shaped connecting ribs, which comprises the following conditions: 1, a vibration transmission sheet body is arranged, and the vibration transmission sheet body comprises one or more groups of thin kidney-shaped connecting ribs; and 2, the value of the ratio of the width wend of the two ends of the thin kidney-shaped connecting rib to the width wmiddle of the middle section of the connecting rib is as follows: by adopting the design of the vibration transmission sheet of the thin kidney-shaped connecting rib, the problems in two aspects can be solved at the same time: 1, the problem that the service life of the vibration transmission sheet is influenced due to non-uniform distribution of internal stress in the connecting rib is solved; and secondly, the equivalent average width of the connecting rib is reduced, so that the stiffness coefficient of the vibration transmission sheet is reduced, the resonant frequency of the vibrator is reduced, and the low-frequency performance of the bone conduction earphone and the tactile feedback actuator is improved.

The invention relates to an anti-deformation leveling algorithm based on a foot-ground contact model and a platform rigidity model. The anti-deformation leveling algorithm comprises the steps that a foot-ground interaction load-settlement model, a platform load-deformation rigidity model and a leveling algorithm with feed-forward compensation are established; a foot-ground interaction load-settlement model is adopted to describe foot-ground contact settlement behaviors, and the landing leg settlement amount is predicted by identifying ground rigidity parameters; secondly, establishing a platform structure stiffness matrix, quantifying a platform load-deformation relationship, performing simulation calculation on a platform system under a typical leveling pose by using a finite element method, and obtaining stiffness coefficient matrixes corresponding to different poses; and finally, designing a leveling algorithm with feed-forward compensation, and superposing the total compensation amount to leveling control output by predicting the landing leg settlement amount and the landing leg structure deformation amount so as to realize feed-forward control. According to the method, the foot-ground contact model and the platform load-deformation rigidity model are constructed, and rapid and stable leveling is realized through a dual-mode control algorithm.

The application discloses a parameter identification device and method based on a Lugre friction model. The method comprises the following steps: creating a PID closed-loop control system configured with the Lugre friction model, drawing a first characteristic curve of output rotating speed w and friction torque F fric ; identifying Coulomb friction and stribeck speed of the friction torque F fric according to the first characteristic curve; obtaining a peak voltage Umax input by a servo motor; inputting a speed extremely slowly changing identification voltage to the servo motor, the identification voltage rising from an initial voltage to the peak voltage Umax at first and then falling from the peak voltage Umax to a negative peak voltage Umax; obtaining a displacement S between the servo motor and a controlled object, and drawing a second characteristic curve of the displacement S and the identification voltage; identifying bristle stiffness coefficient σ0 according to the second characteristic curve; creating a current loop of the servo motor in the PID closed-loop control system; drawing a third characteristic curve of displacement response of the servo motor; and identifying bristle damping coefficient σ1 according to the third characteristic curve.

The invention relates to the technical field of micro-force measurement and calibration, and discloses a friction sensor traceable calibration method based on electrostatic force and flexible dangling, and the method comprises the steps: obtaining the dangling rigidity coefficient of parallel opposite-side flexible dangling and the capacitance gradient of a cylindrical capacitor matrix, and analyzing the response relation between the voltage square and the displacement. Determining the minimum effective loading voltage of the contact between the suspension and the sensor so as to establish a calibration zero point; the stiffness coefficient of the sensor to be calibrated is calculated on line, finally, a series of target force voltages are calculated and applied based on the obtained parameters, a series of traceable target forces are generated on the sensor, and calibration is completed. According to the method, the initial force error is eliminated by establishing the real calibration zero point, the direction purity of the loading force is ensured by utilizing the motion characteristic of the flexible dangling, the force value is traced to the basic quantity of the international unit system, and the calibration accuracy and reliability of the friction sensor are improved.

The utility model relates to the technical field of spring stiffness coefficient detection, in particular to a spring stiffness coefficient measuring device. Comprising a mounting seat, a first suspension part, a harmonic oscillator, a first sliding seat in sliding connection with the mounting seat, an amplitude calibration block fixedly mounted on the first sliding seat, a sensing frame in sliding connection with the amplitude calibration block and a sensor mounted on the sensing frame, the first suspension part is fixedly mounted at the top of the mounting seat, and first scales are arranged on the mounting seat; the first sliding seat is provided with first vernier scales, the sensor is connected with the sensing frame in a sliding mode, the sensor is provided with a sensor sensing opening, and the top face of the amplitude calibration block can abut against the bottom face of the harmonic oscillator. According to the spring stiffness coefficient measuring device, the position of the sensor is moved upwards, so that the sensor can still detect the passing of the harmonic oscillator after the vibration amplitude of the spring is reduced, the measurement error of the vibration period is further reduced, and the calculation precision of the spring stiffness coefficient is improved.

This invention relates to a method for identifying the elastic modulus and loss factor of functionally graded coatings under thermal conditions based on vibration testing. It belongs to the field of structural vibration and material parameter identification technology, and includes: preparing a metal plate specimen coated with a functionally graded coating, and obtaining structural geometric parameters, component material parameters, and thermal vibration environment parameters; applying vibration excitation to the metal plate specimen under thermal conditions to obtain the test natural frequency and test damping ratio of the target order; establishing an equivalent material parameter model of the functionally graded coating to obtain the equivalent Young's modulus, shear modulus, Poisson's ratio, and density of the coating material, and calculating the transformation stiffness coefficient; establishing an analytical dynamic model of the metal plate specimen under thermal conditions based on first-order shear deformation theory and thermoplastic theory to obtain the theoretical natural frequency and theoretical damping ratio of the corresponding order; constructing an error function constrained by the natural frequency and resonance response, and obtaining the equivalent elastic modulus and loss factor of the functionally graded coating through iterative optimization based on a particle swarm optimization algorithm.

This invention discloses a semi-analytical method and system for calculating the stiffness and damping coefficients of foil gas dynamic bearings, relating to the field of air conditioning and clothing temperature control technology. It aims to address the shortcomings of traditional Reynolds equation methods in terms of accuracy and universality, as well as the low computational efficiency and mesh distortion issues of existing CFD methods. The method includes: constructing a fluid-structure interaction (FSI) computational model to calculate and obtain the static equilibrium position of the journal; applying an eccentricity perturbation at the static equilibrium position and performing an additional steady-state FSI calculation to obtain the four stiffness coefficients of the foil bearing using a first set of analytical formulas; applying small-amplitude simple harmonic vibrations along the x and y directions to the journal and performing two transient FSI calculations to obtain the four damping coefficients of the foil bearing using a second set of analytical formulas. This invention combines high accuracy and high computational efficiency, providing an efficient and reliable analytical tool for evaluating the dynamic characteristics of foil bearings and designing the stability of the rotor systems they support.