JVE International
Not a member yet
1200 research outputs found
Sort by
Study on three axis vibration measurement technology of roller bearing
Get PDFTo evaluate vibration level of a tapered roller bearing fully, a new measuring method is proposed, which can cover the vibration acceleration in three directions simultaneously. In the paper, a concept of primary vibration will be presented for three axis vibration picked up from an outer ring of bearing, and the corresponding vibration acceleration measuring system will be introduced. Experimental data will be given to illustrate the advantage of the new measuring technology in the evaluation of bearing vibration level. The research results show that the presented measuring method will be more valuable in evaluating the vibration level of tapered roller bearing used in a precision machine system
Simulation of optimal control of industrial corporations that produce complex dynamic systems engineering
Get PDFIn the article economic models to improve management efficiency by industrial corporations on the basis of scenario planning, management hierarchies Corporation. The role of business process reengineering in the formation of the integrated structures as a tool for the restructuring of the system of material, financial and information flows, aimed at reforming the organizational structure, optimizing the use of resources, improving the quality of products
Electromechanical coupling characteristics and synchronization control of two-hammer synchronous vibration system
Get PDFTwo-hammer synchronous vibration system which consists of two hammers is a complex electromechanical system with complex electromechanical coupling. In this paper, electromechanical coupling characteristics of this system are studied in detail using the methods of theoretical derivation, numerical simulation and experiment. The kinetic models of this system are established, and approximate expressions of electromechanical coupling strength are solved using periodic averaging method (PAM). Basic coupling rules and reasons are obtained. Subsequently, numerical simulation is carried out, and simulation results demonstrate the correctness of model and approach. After that, based on electromechanical coupling characteristics, compound synchronization error feedback and composite control based on inching control (CSEB-CCBIC) strategy and algorithm are proposed, and simulation results validated the effectiveness of the proposed strategy. Finally, experiments are carried out, and the results show that, speed and phase achieve synchronization quickly under the action of synchronization controller, which are agree well with theoretical and numerical results. The research conclusions and methods also provide theoretical foundations for multi-hammer synchronous vibration system and its synchronization control
Constructed solutions of face gear dynamics associated with engagement impact energy decay
Get PDFFace gear drives are focused by many researchers, due to several strong-points versus traditional spiral bevel gear drives. However, calculation solutions of face gear dynamics associated with engagement impact energy decay are not to be constructed, according to the limited published issues. Thus, in the study, a calculation solution of engagement impact energy decay of face gear drives is proposed, a face gear dynamic model is established, and the dynamic mesh forces of an example case of face gear drives without engagement impacts as well as with engagement impacts and engagement impact suppressions are simulated. The results indicate the fidelity of the proposed calculation solutions of face gear dynamics associated with engagement impact energy decay could be accepted. These contributions would improve the developments of face gear drive modifications and engineering applications of face gear drives in the future
Nonlinear dynamic analysis of a coupled lateral-torsional spur gear with eccentricity
Get PDFIn this study, the dynamic behaviors of gear system are systematically analyzed with coupled lateral-torsional vibration caused by the gear meshing. A 4-degree-of-freedom (DOF) lumped parameter dynamic model for a spur gear, considering gravity, backlash, eccentricity, transmission errors, external excitation, is proposed. Parametric studies are performed to understand the influence of key parameters such as rotational speed ω, backlash b and error fluctuation er on the nonlinear dynamic behavior. The frequency response characteristics of spur gear system show that lateral resonance frequency and torsional resonance frequency simultaneously exhibit in lateral direction. In addition, other nonlinear phenomena including various forms of periodic, quasi-periodic and chaotic vibrations are analyzed. The results show that the nonlinear dynamical behaviors such jump discontinuous phenomena, single-sided impact and double-sided impact are strongly attributed to interaction between backlash, eccentricity and error fluctuant amplitude. Significantly, the appropriate rotational speed and decrease error fluctuant amplitude could effectively control the nonlinear vibration. Whereas the backlash has a complicated effect on the nonlinear dynamical characteristics. The results presented in this paper show that an analysis of the coupled lateral-torsional vibration (CLTV) of the spur transmission gear system. Some research results presented in this paper are useful to dynamic design and vibration control of spur gear transmission system
Dynamic analyses of osteoblast vibrational responses: a finite element viscoelastic model
Get PDFMechanotransduction is an important process that influences bone remodeling and maintains viability of bone cells. To understand the effect of the vibrational mechanical stimulation on biomechanic responses of bone cells, a viscoelastic osteoblast finite element (FE) model was developed. Firstly, the mode shapes and natural frequencies of a spreading osteoblast were assessed using the FE modal analysis. The osteoblast FE model predicted the natural frequencies of osteoblasts (within the range about 19.99-34.48 Hz). Then, the effect of acceleration on the vibrational responses of in-vitro cultured osteoblasts was investigated. Three different accelerations of base excitation were selected (0.15g, 0.3g and 0.5g, where g = 9.8 m/s2) and the vibrational responses (displacement, strain and stress) of osteoblasts were simulated. It was found that values of displacement, strain and stress increase with the increase of base excitation acceleration. In addition, the response values in Z-direction are much higher than those in the other directions (X, Y-direction) for the same base excitation acceleration. These findings will provide useful information to understand how vibrational mechanical stimulus influences bone cells and provide guidance for in vitro cell culture and experimental research and ultimately clinical treatment using the external vibrating loading
Numerical investigation on noise reduction for an in-line fan equipped with Helmholtz resonator
Get PDFThis research intends to analyze and improve the flow-induced noise of an in-line fan with Helmholtz resonator by the numerical simulation. At first, the flow and acoustic fields associated with the fan are simulated and analyzed via the CFD simulation. Subsequently, a thorough understanding on the aerodynamic and acoustic features of this mixed-flow fan is achieved. Later, to reduce the fan noise, a set of Helmholtz resonators for this inline-fan is designed and installed onto the critical regions inside the fan. Also, the flow-induced-noise reduction due to the resonator is examined and discussed in details. As a result, the maximum noise reductions on the 1st and the 2nd characteristic frequencies are obtained at 6.9 dBA and 9.8 dBA, respectively. Moreover, there is a minor noise-elimination effect found on the other harmonic frequency while the significant result appears on the designed characteristic frequency. However, all resonators used yield a significant noise reduction at the second BFF. In conclusions, a comprehensive parametric study on Helmholtz resonator is carried out and summarized for attaining a design guideline for its application on the in-line fan. The accomplishment of this study provides a systematic scheme of noise reduction for an inline-fan with the addition of Helmholtz resonator design
A method for modal loss factor estimation based on Gauss-Newton iteration
Get PDFA new approach based on Gauss-Newton iteration is proposed to estimate modal damping. Noise resistance of the proposed method and half-power bandwidth method are analyzed and compared by plenty of simulations with different signal-to-noise ratios (SNR). The proposed method is more accurate and stable than half-power bandwidth method in all SNRs, especially when the noise level is high. If SNR ≤ 30 dB, the proposed method should be used for damping estimation instead of half-power bandwidth method. A damping estimation experiment is carried out with both methods, and the results indicate and verify that there is smaller variability for the proposed method
Influence of web plate holes on the radiation noise characteristics of wheels of the high speed train
Get PDFThe finite element model of wheels without holes was established to compute its free modal and compare with the experimental result. The relative error was controlled within 5 %, which indicated that the finite element model in this paper was reliable. Based on the finite element and geometric model, the acoustic boundary element model of wheels was established to compute the radiation noise of wheels under the action of radial and normal excitation forces. Results showed that the change trend and value of radiation noises of wheels were similar under the action of two kinds of excitation forces when the analyzed frequency was lower than 1421 Hz. However, the radiation noise of wheels under the action of two kinds of excitation forces was significantly different and presented obvious directivity in three planes with the increase of the analyzed frequency. Then, models of wheels with 5, 6, 9 and ellipse holes were established to compute radiation noises and conduct comparative analysis. Results showed that the radiation noise of wheels with 6 holes was relatively minimum under radial and normal excitations and did not decrease with the increase of the hole number. The radiation noise of wheels with circular holes made certain improvement, compared with the radiation noise of wheels with ellipse holes. Distribution curves for the directivity of radiation noises of various wheels were highly symmetrical in the Z plane and radiation noises had relatively maximum in the position of multiples of 30°. The curve for the directivity of radiation noises of wheels with 5 holes was clearly different from that of other structures in the Y plane
Residual useful life predictions for train’s rolling bearing based on proportional hazard model
Get PDFThis paper studies the rolling bearing of the train and it puts forward a method of predicting the residual useful life (RUL) of the train’s rolling bearing using the proportional hazard model (PHM). First, the problem of RUL predictions for the train’s rolling bearing is described. Secondly, PHM is introduced, including the basic form, sample data, parameter estimation and prediction. Then, the method of RUL predictions using PHM is put forward. Finally, PHM has been validated by the total life data of the train’s rolling bearing