Analysis Of Dynamic Characteristics Research Articles

Dynamic monitoring and characteristic analysis of a long-span operational bridge from high-rate sensor responses using RAAVMD approach

Dynamic monitoring and characteristic analysis of a long-span operational bridge from high-rate sensor responses using RAAVMD approach

Analysis on dynamic characteristics and control strategy of medium structure network converter in new energy medium voltage flexible interconnection project

Abstract In view of the possible voltage and current overshoot problems in the process of new energy grid connection, the dynamic characteristics analysis and control strategy of the network converter in the new medium voltage flexible interconnection project are proposed. Firstly, a synchronous control strategy based on voltage phase and amplitude compensation is proposed. Then, based on the characteristics of new AC-DC hybrid distribution network, the new energy medium voltage flexible interconnection network is analyzed. The simulation experiment reveals the dynamic response characteristics of the new energy grid converter under frequency interference and load change.

Simulation Analysis of Powered Parachute Motion Characteristics based on Motor Thrust and Flap Deflection Control

In this paper, a distributed new type of parafoil is proposed, conducting its dynamic modeling and motion characteristic analysis, thereby laying the foundation for subsequent trajectory tracking research and physical experimentation. First, the dynamics of the parafoil and payload are analyzed, and the dynamic model of the entire parafoil system is derived from this analysis. Then, the kinematic characteristics under control inputs of bilateral pull-down, unilateral pull-down, and unilateral pull-down with differential thrust are examined using the simulation model; Simulation results indicate that the established 8-DOF dynamic model accurately describes the parafoil's motion. The proposed differential control increases yaw motion response speed and provides a basis for subsequent trajectory tracking research and physical experiments. The proposed differential control enhances the yaw motion response speed and reduces the relative motion between the wing parachute and payload to a certain extent. Simulation analysis verifies the model's validity and the control method's feasibility.

Analysis of Static and Dynamic Characteristics of 1.2 kV 4H-SiC Trench MOSFETs with Trenched P-Source and Buried P+ Layers

Analysis of Static and Dynamic Characteristics of 1.2 kV 4H-SiC Trench MOSFETs with Trenched P-Source and Buried P+ Layers

Comparison of evaluation methods for the dynamic characteristics of railway hydraulic dampers

The EN and Area methods are commonly reported procedures for evaluating dynamic damper characteristics, both predominantly relying on time-domain data of damper force and displacement, with the EN method established as a standard in EN13802. However, these time-domain approaches do not fully utilize all experimental data and have inherent limitations that can impact the accuracy of the results. To address this challenge, this study introduces a calculation method based on the Fast Fourier Transform (FFT), which shifts the analysis from the time domain to the frequency domain, allowing for more reliable determination of phase angle, dynamic stiffness, and damping. Comparative analysis of dynamic test results on typical hydraulic dampers reveals that traditional time-domain methods lead to abnormal fluctuations in dynamic stiffness at low frequencies due to inaccuracies in phase angle calculations. In contrast, the frequency-domain method delivers more reliable results. Among the tested methods (EN, Area, and FFT), the FFT method aligns most closely with the standard EN method, showing discrepancies of less than 10%, and demonstrates greater robustness under noisy conditions. In comparison, the Area method exhibits higher sensitivity to sampling frequency variations, resulting in less reliable outcomes. This study provides practical insights for enhancing damper performance evaluation and recommends the frequency-domain method as a reliable tool for dynamic characteristic analysis, particularly in applications where noise resilience is required, while the EN method remains suitable for low-noise conditions.

Modification and nonlinear dynamics characteristics analysis of herringbone gears based on coupling of meshing force and stiffness

Gear modification is an important technology for the design and manufacturing of high-precision gear transmissions, which is an effective method to improve gear meshing performance, reduce vibration, and noise. This paper employs the coordinate transformation method to calculate the meshing angle of herringbone gear, which simplifies the calculation of the relative displacement of the meshing line. Also, considering the influence of dynamic meshing force at the meshing point of gear pairs on time-varying meshing stiffness, an improved nonlinear dynamic model was established, and a novel internal excitation real-time correction method was proposed to predict the system’s dynamic characteristics more accurately. Next, the effects of different modification methods, modification amounts, and damping ratios on the nonlinear dynamic characteristics of the herringbone gear pair were analyzed. The obtained results show that the average relative displacement of the meshing line increases with the increase of the amount of modification. Moreover, its standard deviation decreases with the increase of the modification in some rotating speed ranges. In some cases, it can even be reduced by more than 50%. When the damping ratio decreases gradually, the axial modification can shorten the chaos interval by 52.68%, but the periodic window will disappear after modification.

Dynamic characteristics analysis of high-speed motorized spindle system considering unbalanced magnetic pull and non-linear bearing restoring force

Abstract The high-speed motorized spindles play a pivotal role in modern machining, holding vast application potential and profound research significance. To analyze the dynamic characteristics of the high-speed motorized spindle system, an fourteen-degree-of-freedom dynamic model has been established using the lumped parameter method, and numerical methods have been employed for computation. Then, the bearing stiffness, the variation of the restoring force, and the unbalanced magnetic force are considered. Additionally, the parameters of the model were optimized using the genetic algorithm. Finally, the effects of spindle speed, initial eccentricity, and bearing parameters on the vibration behavior and stability of the motorized spindle were analyzed using bifurcation diagrams, time-frequency waveform, spectra, trajectories, and Poincaré. The study provides a valuable reference for the design and optimization of motorized spindle systems.

Dynamic characteristic analysis and load design of large floating structures based on experimental design

Dynamic characteristic analysis and load design of large floating structures based on experimental design

Dynamic thermal characteristics analysis of Integrated space nuclear reactor with core and Stirling power conversion components

Dynamic thermal characteristics analysis of Integrated space nuclear reactor with core and Stirling power conversion components

Comparative analysis of dynamic characteristics between magnetorheological grease and graphite magnetorheological grease

Comparative analysis of dynamic characteristics between magnetorheological grease and graphite magnetorheological grease

Nonlinear Dynamic Modeling and Dynamic Characteristics Analysis of a Coaxial Reverse Closed Differential Herringbone Gear Transmission System Considering Floating Backlash

Nonlinear Dynamic Modeling and Dynamic Characteristics Analysis of a Coaxial Reverse Closed Differential Herringbone Gear Transmission System Considering Floating Backlash

Analysis of Dynamic Characteristics of Pricing in Telecommunications Market Using Agent-Based Model

Analysis of Dynamic Characteristics of Pricing in Telecommunications Market Using Agent-Based Model

Geometric generation and meshing characteristics analysis of a new S-shaped gear drive

A new type of S-shaped gear drive with a tooth profile combining involute and circular-arc curves is proposed in this paper. Tooth profile design includes convex involute, convex circular-arc, concave involute, and concave circular-arc curves is carried out. Geometric generation and mathematical model of tooth surfaces of the S-shaped gear are established based on imaginary rack method. Utilizing Hertz contact theory, the calculation formula of contact stress of tooth surfaces is provided. Furthermore, simulation analysis of contact stress based on finite element method under various working conditions is studied using ANSYS/Workbench software. And the comparisons of stress results with general involute gear are also provided. Dynamic characteristics analysis of the generated tooth surfaces is put forward using the established virtual prototype. Normal contact force, circumferential force, axial force and radial force of tooth surfaces both S-shaped gear and involute gear are analyzed. Research results show that the developed S-shaped gear has better transmission performance than involute gear. Further study on dynamic analysis and manufacturing method will be carried out.

Dynamic characteristic analysis and strength optimization of vibrating screen based on computer simulation technology

The dynamics and modal characteristics are important basis for the stable operation of vibrating screen. A multi-body dynamic model of vibrating screen was established based on ADAMS, and the laws of change in the center of mass and the dynamic response of the vibration isolation system were obtained. The amplitude-frequency response results of acceleration under varying stiffness and damping coefficients were compared and analyzed, providing a crucial foundation for enhancing vibration isolation performance. The vibrating screen was analyzed for its modal characteristics using ANSYS, and the natural frequencies and vibration patterns were investigated. The distribution and main causes of the maximum resonance displacement were discussed. Drawing on the results of stress and modal shapes, the strength of the vibrating screen was significantly enhanced through multi-objective optimization methods without increasing its weight. The findings indicate that the optimized structure can achieve a 32.2 % reduction in peak stress.

Dynamic characteristics analysis and optimization design of medical grinding machine

In order to improve the stability and reliability of medicinal grinding machine, reduce vibration and noise, and enhance the strength of load-bearing, a scheme for optimizing dynamic response characteristics without increasing mass was proposed based on multi-objective optimization methods. Using the finite element method, the modal analysis was conducted on the entire model of the grinding machine to determine its natural frequencies and vibration modes. The structural optimization design was carried out with the optimization goal of having a sixth-order natural frequency below 30 Hz and a seventh-order natural frequency above 100 Hz. The stress distribution was obtained by conducting the strength analysis on the connecting rod structure. The optimization design of the structure was carried out with the minimum value of the stress peak and the maximum value of the fatigue safety factor as the optimization objectives. The results show that the multi-objective optimization method can make the equipment avoid the resonance zone and reduce the peak stress, which is of great significance for improving the performance of the medical grinding machine.

Dynamic characteristics analysis and optimization of oil tank

The response of oil tanks under dynamic loads is the key to ensuring safety, and the analysis of stiffness and strength is very necessary. Modal analysis was carried out on the oil tank to obtain the natural frequencies and vibration modes. Under specific excitation frequencies, the stress responses of the dangerous points of the front head, the rear head, the cylinder, and the transverse wave plate were calculated respectively. Three filling rates of 30 %, 50 % and 70 % were respectively selected for the structural response study, and the structural deformation and stress responses of the storage tank structure under the impact of different volumes of liquid were obtained. According to the dynamic response analysis, the structure of the front head and transverse wave plate were strengthened. It can be known from the comparison of mechanical properties that the optimized structure can significantly improve the stiffness and strength, and effectively ensure the safety of the oil tank.

Dynamic response analysis and optimization of orbital support structure

In order to further enhance the stability of the orbital transportation, the modal characteristics of the orbital support structure were simulated and analyzed. The multi-objective optimization method was applied to design the structure for lightweighting while increasing the first-order natural frequency and reducing the stress peak. Using ANSYS Workbench, the parametric finite element model was established, the length of the intermediate support rod, and the lateral length of the rib were regarded as the parameterized dimensions. Through dynamic characteristic analysis, the natural frequencies, modal shapes, and harmonic response characteristics were obtained. Parametric samples were obtained by using Latin square method, and the approximate model was fitted by polynomial function. Multi-Objective Genetic Algorithm and Sequential Quadratic Programming were applied for optimization calculation. The results indicate that the structurally lightened design can attain higher strength and stiffness.

Modeling and Dynamic Analysis of Double-Row Angular Contact Ball Bearing–Rotor–Disk System

This article presents a general numerical method to establish a mathematical model of a bearing–rotor–disk system. This mathematical model consists of two double-row angular contact ball bearings (DRACBBs), a rotor and a rigid disk. The mathematical model of the DRACBB is built on the basis of elastic Hertz contact by adopting the Newton Raphson iteration method, and three different structure forms are taken into account. The rotor is modeled by employing a finite element method in conjunction with Timoshenko beam theory, and the rigid disk is modeled by applying the lumped parameter method. The mathematical model of the bearing–rotor–disk system is constructed by the coupling of the bearing, rotor and disk, and the dynamic response of the bearing–rotor–disk system can be solved by employing the Newmark-β method. The validation of the above mathematical model is demonstrated by comparing the proposed results with the results from the existing literature and finite element software. The dynamic characteristics of the DRACBBs and the dynamic response of the bearing–rotor–disk system are investigated by parametric study. A dynamic characteristic analysis of the DRACBB is conducted to ensure the optimal structure form of the DRACBB under complex external loads, and it can provide a reference for the selection of the structural forms of DRACBBs.

Modeling and dynamic characteristics analysis of concentrating-receiver-heat exchanger system of sCO2 solar thermal power plant

In a supercritical carbon dioxide (sCO2) solar thermal power plant system using solid particle as the heat absorption and transfer medium, the concentrating-receiver-heat exchange coupled system composed of a heliostat field, solar particle receiver, and particle/sCO2 heat exchanger is one of the most important subsystems in the power plant system, and its dynamic characteristics directly affect the performance of the whole system. In this paper, taking the 200kWe sCO2 solar thermal power plant as the research objective, firstly, a discretized lumped parameter model of the coupled system was established to study the dynamic performance and operational characteristics based on the TRNSYS platform, and the following characteristics of some key parameters such as particle and sCO2 outlet temperature to the DNI variation were deeply studied without taking any control measures. The results indicate that the particle and sCO2 outlet temperature are positively correlated with the DNI variation and are highly sensitive, and the efficiency of the particle receiver is basically maintained at around 0.7 whether it is sunny or cloudy; Secondly, in order to achieve the rated outlet design parameters, the dynamic characteristics on June 13 and 15, 2023 with a PID control strategy were also studied. The results show that the particle outlet temperature can be maintained at 800 °C by controlling the particle inlet mass flowrate in the particle receiver, while the sCO2 outlet temperature can be guaranteed at 550 °C by adjusting the sCO2 inlet mass flowrate in the heat exchanger with the condition of mild DNI variation. Besides, it is also found that, the PID control is unlikely to be effective under severe DNI changes. Therefore, the addition of buffer particle tanks is essential to compensate for the intermittency of the DNI in the system design process.

Enhancing Oil Recovery in Low Permeability Reservoirs through CO2 Miscible Flooding: Mechanisms and Dynamics.

Understanding the dynamic characterization of the CO2 miscible flooding process in low permeability reservoirs and its mechanism for oil recovery enhancement is crucial for controlling CO2 miscible flooding sweep efficiency and further enhancing oil recovery. This study was conducted in a low permeability reservoir in Jilin, China, using both online nuclear magnetic resonance CO2 miscible flooding and long-core CO2 miscible flooding experiments. A refined dynamic characterization of the CO2 miscible flooding process from the macroscopic core scale to the microscopic pore scale was achieved through multiple spatial online nuclear magnetic resonance testing methods. Analysis of dynamic characteristics of physical parameters was based on long-core displacement experiments and gas chromatography. This study summarizes the influence mechanism of CO2 miscible flooding on enhanced oil recovery in low permeability reservoirs and demonstrates the feasibility of CO2 miscible flooding. The results indicated that (1) CO2 miscible flooding enables simultaneous oil recovery from micro-, meso-, and macropores, significantly improving displacement efficiency. (2) The recovery process unfolds in two stages: the initial CO2 miscible flooding stage before gas breakthrough and the subsequent CO2 miscible transport stage after gas breakthrough. (3) Both stages are instrumental in expanding the macroscopic swept range of CO2, thereby enhancing oil recovery. (4) The miscibility of CO2 with crude oil can affect the oil's composition. (5) The combined effect of miscible flooding and transport underpins the high displacement efficiency of CO2 miscible flooding. Emphasizing these critical aspects could enhance oil recovery from CO2 miscible flooding in field production.