Calculation Of Vibration Response Research Articles

Research on key process parameters and characteristic vibration of steam turbine shafting

Steam turbines are a major source of vibration and noise when submarines are working. How to improve the technological level of steam turbines and reduce the vibration generated by them so that submarines can achieve the purpose of acoustic stealth has always been a hot topic of research. However, blindly improving the overall technological level of steam turbines will not only increase the manufacturing cost but also prolong the manufacturing cycle of submarines. Therefore, this paper makes a reasonable model of each type of process parameter for a certain type of steam turbine design drawings for ships. Subsequently, a dynamic model of the steam turbine shafting based on the transfer matrix was established, and experiments were designed on five groups of design parameters with strong vibration sensitivity of the steam turbine shafting. The vibration response calculation under multiple process parameters of the steam turbine shafting was carried out in combination with the two. The connection between the key process parameters of the steam turbine shafting and the characteristic vibration was established, and the influence mechanism of the key process parameters of the steam turbine shafting on the characteristic vibration was analyzed.

Low to Middle Vibro-Acoustic Noise Prediction in Ship Cabin by Using Plate-Cavity Coupling Model

Abstract A plate-cavity coupling method based on modal expansion technique in the closed sound cavity was introduced, aiming at ship cabin structural noise. Using this method, a coupled equation was established. The structural vibration acceleration of the target cabin was extracted from a ship vibration response calculation, applied to the model. Then the target cabin noise value was obtained through numerical calculation. The effectiveness and reliability of the method were validated through experiments. The coupled model predicts noise in the cabin does not require fluid finite element model of the cabin air, thus greatly reducing the calculation time compared with the pure finite element method. It was shown that the method is suitable for the calculation of noise in a single ship cabin; the method has a high calculation efficiency. Furthermore, the calculated result is a continuum. On the one hand, it can be conveniently converted to an octave or 1/3 octave according to the specification. On the other hand, the form of the continuum also provides a corresponding response to the subsequent vibration and noise control.

Concept Calculation Tool for Dynamics of Generator Set Common Baseframe

The Natural frequency and vibration response calculation process of a generator set was automatized so that it can be used in a generator set common base frame concept design. The implementation of automatization was to be done so that no profound knowledge about the finite element method is needed to execute calculations and that computation times are short. Substructuring is used for certain parts of the generator set model to reduce the computation times for more a efficient concept design process. The common base frame concept design is implemented to the process by using a design tool in which the finite element model generation from parametric geometry is automatized. Generator set finite element model generation, natural frequency and vibration response calculations and post-processing of analysis results were implemented by developing a calculation tool for this purpose. The calculation tool is an independent application that uses Abaqus simulation software to execute analyses.

Forced Vibration Response Calculation of Rotating Short Thin Cylindrical Shells For Various Boundary Conditions

Forced Vibration Response Calculation of Rotating Short Thin Cylindrical Shells For Various Boundary Conditions

Lateral vibration of hydro turbine-generator rotor with varying stiffness of guide bearings

The rotor consisted of rotating components and origin of energy transfer is the source of all vibrations in a hydro turbine generator unit. Among all vibration modes, the lateral mode is of the greatest concern. A lateral vibration response calculation model for rotor-bearing system with the nonlinear characteristics of the guide bearing's stiffness is presented in this paper. The model for hydro-generator rotor combines finite element model with the varying guide bearing's stiffness, the gyroscopic effect, unbalanced magnetic pull, hydraulic force and mechanical forces to calculate natural frequencies and steady state response. Take Francis turbine unit with three guide bearings for an example, the unit's lateral vibration characteristics and response of rotating components had been simulated by using FEM. The lateral vibration characteristics and response amplitude at rotating parts had been analyzed by varying stiffness simultaneously or one of the three guide bearings based on the assumption of elastic supporting models, and the influence of rotating speed, phase difference between the unbalanced forces on the vibration response had also been analyzed by the simplified analysis at the designed guide bearing stiffness. It shows that accounting for bearing stiffness and support structure flexibility, and then understanding the resulting in vibration behavior is an important factor in enhancing the stability of a hydro turbine generator rotor. The simulation results show that, for a vertical-mounted hydro turbine generator unit, there exists a common characteristic in the first three vibration mode, that is, the maximum amplitude is at the exciter in the first vibration mode and at the runner in the second vibration mode respectively, and the maximum amplitude is near the exciter or rotor in the third vibration mode. These results have great significance for the optimization design of the supporting structure of a hydro turbine generator unit.

Acoustic Simulation for the Gearing Engagement System

This paper concentrates on modeling the gear transmission system using a three-dimensional finite-element approach for the acoustic radiation analysis and control. The combination of dynamic analysis and vibration response calculation for the gear engagement system can contribute to evaluate acoustic radiation. A case study of for gear engagement system internally excited with gear mesh fluctuation is presented in this research. Acoustic radiation quantity investigation has been carried out by Virtual.Lab Acoustics software. It can be concluded that numerical simulation is very important during gear system design and noise control.

Correction on Parameters in Torsion Vibration Model for Turbine-Generator Shafts

The accuracy of parameters in model has important influence on torsion vibration analysis of turbo-generator shafts. In this paper, a method for torsion vibration response calculation based on multistage lumped mass model is introduced. A method for identification and correction on stiffness and damping in torsion vibration monitoring is put forward. Pre-revision on shaft stiffness is realized through analytic calculation of the temperature distribution of turbine-generator shafts. The difference of natural frequencies and response of torsion vibration of shafts are calculated and analyzed after parameter correction, which offers the reference for studying torsion vibration fatigue of shafts.