Influence Of Dynamic Characteristics Research Articles

A new dynamic modelling methodology of a force measuring system for hypersonic impulse wind tunnel

This paper aims to improve the dynamic modeling accuracy of the whole complex assembly of the wind tunnel measuring system. First, an analytical formula describing the relationship between dynamic characteristics and test accuracy of the force measuring system (FMS) is derived, and the influence of dynamic characteristics on test accuracy is analyzed. Subsequently, the method of single component modeling in FMS is elaborated. Furthermore, a modeling of bolted joint based on uneven contact surface-pressure distribution is proposed. In order to verify the effectiveness of FMS dynamic modeling method proposed in this research, the calculated and experimental modes are compared. Comparison results show that these two modal modes of each order are very similar, and the error range of frequency between them is 0.5%–13.4%. Finally, the theoretical results are in good agreement with the experimental results, which confirms the validity of the proposed modeling method.

Вплив динамічних характеристик тракторних гідроциліндрів на їх працездатність

Вплив динамічних характеристик тракторних гідроциліндрів на їх працездатність

Analysis of the Influence of Dynamic Properties of Structures on Seismic Response According to Montenegrin and European Regulations

The motion of strong earthquakes causes nonlinear deformation and damages to the structure. For structural systems of buildings, domestic and European (EC8) regulation apply algorithm of seismic design based on reference linear-elastic methods that are carried out in two phases. Phase I includes determination of dynamic characteristics of structure, which are then used in phase II for calculation of seismic effects. In this study, parametric analysis of influence of dynamic characteristics of structure was done on multiple numerical examples, according to domestic and EC8 regulations and comparison of results.

Optimization Design of Vibratory Jaw Crusher with Double Cavities Based on MATLAB

The vibratory jaw crusher with double cavities was designed for reducing energy consumption by more crushing and less grinding. The dynamic model is established based on its structural characteristics, and the standard state equations are built by using Lagrange method. Based on MATLAB, the trajectory diagrams of the moveable jaws in the two cavities are obtained by Range-Kutta method. The influence of dynamic characteristics on yield and grain size is gained ,and the optimization design idea for the crusher is put forward.

Engineering calculation of dynamic impedances and starting characteristics for high-voltage induction motors

Starting characteristics and dynamic impedances are the key parameters for the research of high-voltage induction motor. The measurement of starting characteristics and dynamic impedances for high-voltage induction motors can present problems for both manufacturers and users, so a practical and feasible calculation method is necessary. In order to facilitate the engineering application, this paper presents a set of useful calculation method for motor transient torque, current, and impedances. In the calculation, the influence of dynamic characteristics and impedances on each other, which are often neglected in previous calculation, is considered. So the influence of impedances on the characteristic curves can be analyzed more accurately using this method. Based on the earlier analyses, this paper further studies the influence of different start-up voltages on the stator leakage reactance. Finally, through the analysis and calculation results of many motors, it can be verified that only when the relation between starting characteristics and dynamic impedances is considered in calculation process will the results be better in line with the actual value. The algorithm is suitable for engineering use. Copyright © 2014 John Wiley & Sons, Ltd.

Study on the Influence of Gear Rattling on Pitting Fatigue Failure

The pitting fatigue failure is one of the main gear failure modes, and it has extremely important significance in studying on the influence of dynamic characteristics on pitting fatigue failure. The article has set up increasing-speed test-bed, using photoelectric encoder and NI DAS to measure and collect rotational-speed pulse of driving wheel and driven wheel. Arc-length difference and rotational-speed difference of driving wheel and driven wheel are analyzed to verify gear rattling phenomenon under increasing-speed transmission. And then gear surfaces under certain cycles are observed and analyzed utilizing surface mapping microscope to explore the influence of gear rattling on pitting fatigue failure under increasing-speed transmission. It is shown that there is rotational-speed difference between driving wheel and driven wheel, which indicates that gear rattling phenomenon appears in the meshing process, or more precisely, gear rattling phenomenon appears on both surfaces of the tooth because rotational-speed difference fluctuates bilaterally. In addition, tooth surface contact stress is 221.3Mpa, in theory, if actual contact stress is less than fatigue limit, pitting fatigue failure should not occur. However, through gear surface observation, pitting phenomenon authentically appears with the tendency from micro pitting to destructive pitting. In a word, gear pitting fatigue failure is induced by gear rattling to a certain extent.

Analysis of Seismic Response for an Extradosed Cable-Stayed Curved Bridge Based on Different Design Parameters

Based on the characteristics of low tower and few cables in extradosed Cable-Stayed bridges, simulation models are established for investigations of structural dynamic characteristics under different design parameters, which is related to the practical engineering of Longjing Bridge. As the design radius and pier beam connection form are chosen for the variable, the paper is focus on the influence of dynamic characteristics under the two parameters in extradosed cable-stayed curved bridges. Since the earthquake response spectrum data from National seismic code in 2008 and with the CQC vibration mode combination method, the diversified models are built by Midas/civil so as to explore the earthquake response mechanism under different design parameters. The result show that these two design parameters have some great impacts on dynamic characteristics of extradosed cable-stayed curved bridges, which has direct effect on the bridge seismic performance. The conclusion is the important reference for practical engineering and providing basis for seismic design parameters, but also for seismic design and construction in extradosed cable-stayed curved bridges.

Dynamic Modal Analysis of CNC Precision Rotary Worktable

The dynamic performance of the worktable has a great influence on machining quality. In order to improve the machining precision, the paper conducts the analysis and research on the workability of a numerical control engine bed rotary worktable from a domestic machine tool factory，and discusses the influence of dynamic characteristics of rotary worktable on the precision of numerical control processing. Firstly Ansys finite element analysis was employed to analyze and simulate the modality and natural frequency of the numerical control rotary worktable under various steps. And then, a vibration test on the numerical control rotary worktable to confirm accuracy of the simulation parameters was carried on. Finally a contrast was made between the theoretical analysis and the experimental analysis to point out the resonance frequency and the distortion of the rotary worktable. Also the influence of numerical control rotary worktable on the numerical control processing was discussed.

シート操作力による二輪車の運動特性への影響(人間機械システム・HMI(1),OS3 人間機械システム,ヒューマンインターフェース)

シート操作力による二輪車の運動特性への影響(人間機械システム・HMI(1),OS3 人間機械システム,ヒューマンインターフェース)