Research on torsional vibration monitoring system of ship power shafting

In this paper, the real-time monitoring technology of ship power system torsional vibration is studied. The photoelectric non-contact measurement method is used to measure the torsional vibration intensity of shafting, and the analysis service network management platform is established to realize the functions of real-time monitoring of shafting torsional vibration and upload and collect alarm data, through the front-end system, the torsional vibration strength and other parameters of the shafting are collected and transmitted to the background. The data of the background system is used to calculate and analyze, and the status of the shafting is alarmed. The system realizes continuous monitoring and data recording of torsional vibration index of ship power system, and ensures the operation performance and safe operation of ship power system. It provides theoretical and technical support for the future development of new technologies and related research, such as durability simulation and durability virtual test of ship power critical parts.

Calculation of elements of machine-building structures on vibration strength

A method and an automated system for calculating structural elements for vibration strength have been developed. The calculation algorithms are based on a new method of forming Rayleigh-type functionals and minimizing them by the coordinate descent method. The use of the coordinate descent method avoids the problems associated with the formation, storage and operation of global matrices of stiffness and mass. This makes it possible to solve large-scale problems using only the operational memory of the PC. The developed approach allows to solve problems on own and forced fluctuations. The software is formed on a modular basis, which allows you to improve and expand this package of applications. The software has been tested on a large number of test and application tasks. The proposed calculation method and the developed automated system were implemented in engineering practice.

Vibrational Monitoring of Nested Planetary Geartrain with Unground Pinion

The nested planetary gear train, which has two integrated single-stage planetary gearsets, is one of the newly developed compound gear train that has been successfully applied to the automobile transmissions. In the current study, a certain type of gear fault in the nested gear train, ungrounded pinion, is investigated using a non-destructive approach monitoring its vibration levels. A novel experimental test stand with open and vertical setup has been designed to collect the vibrational data by mounting the accelerometer directly to the gear clutches. Each of the two layers of the compound gear was tested separately. The measured vibrational data were processed with several signal processing techniques, which includes (a) frequency spectrum analysis, (b) time synchronous averaging (TSA) and (c) modulation sideband analysis. The experimental results show that the existence of the ungrounded pinion can be identified with the frequency spectrum analysis of the vibrational data. In addition, the modulation sidebands are also modeled using a modified version of the traditional technique of physical signal modeling. It is shown that the relative phase of the planet and the meshing vibration strength changed by the unground gear is the critical factor for determining the modulation sideband behavior. In addition, the location of the ungrounded pinion can also be determined by the time history processed by TSA.

Effect of Chemical Potential and Atomic-Scale Vibration of Nucleant Surface on Liquid Layering and Heterogeneous Nucleation

This study reveals the key role of chemical potential and atomic-scale vibration of the nucleant surface in dictating pre-nucleation liquid-layering and heterogenous nucleation. The effect of potential-well depth Dw and vibration strength $$\overline{\beta }_{{{\text{std}}}}$$ β ¯ std of the nucleant surface on the layering and nucleation was examined. We found that nucleants with larger Dw and smaller $$\overline{\beta }_{{{\text{std}}}}$$ β ¯ std induce more ordered pre-nucleation layers to enhance nucleation, and proposed that Dw and $$\overline{\beta }_{{{\text{std}}}}$$ β ¯ std shall be considered when searching for effective nucleants.

Vibration Assessment on Various Distance to Demolition Works

Vibration has been a serious problem to be discussed over the past years. Vibration has caused cosmetic damages to buildings and annoyance to the occupants of the building. Sources of vibration are usually produced by construction work, traffic, seismic effect and human activities. In this paper, the amplitude of vibration caused by demolition has been analyzed and the level of vibration and level of damage caused have been determined. Besides, the effect of the vibration strength due to distance from the source has also been studied. The vibration data due to demolition work was obtained and analyzed by using MATLAB software. The analyzed data in graphical form were compared with the Gordon vibration criteria to obtain the vibration limit and the level of vibration damage according to DOE (Malaysia) standard as well. The results indicated that the vibration at 1m distance and 10m distance from the vibration source will cause minor damage to the building whereas the vibration at 25m distance from the source is at the caution level. By comparing the Gordon vibration criteria curve, the vibration from 1m, 10m and 25m distance from the demolition vibration source are not suitable for sensitive equipment. This study also proved that the vibration strength will decrease as the distance from the source increases due to the loss of vibration energy during the propagation of vibration waves. Hence, the further the distance from the source, the weaker the strength of the vibration and lower level of damage on surrounding buildings.

Identification method for assessing the state vibration strength of the aircraft engine

A method foraircraft engine state assessment is described, based on the theory of identification measurements and consisting in the analysis of the regularity properties of the temporal and correlation functions of the vibration signal. An example of an aircraft engine dynamics analysis during flight tests is considered. Four classes of states are distinguished according to the “norm – defect” scale.

Preparation and Properties of Wood Tar-based Rejuvenated Asphalt

In order to explore the applicability of the rejuvenated asphalt with wood tar as the main raw material, the orthogonal test was used to determine the optimal ratio of wood tar-based rejuvenator. The physical properties, rheological properties and components of matrix asphalt, aged asphalt, wood tar-based rejuvenated asphalt and commercial RA-102# rejuvenated asphalt were tested and compared. The results show that the optimal ratio of wood tar-based rejuvenator is 15wt% wood tar, 0.3wt% biomass fiber, 5wt% plasticizer, 0.3wt% compatibilizer, and 1wt% stabilizer of the mass of aged asphalt. Wood tar-based rejuvenator can restore the physical properties of the aged asphalt to meet the specification requirements. The synergistic effect of biomass fiber and plasticizer make the wood tar-based rejuvenated asphalt has good resistance to accumulated permanent deformation, but its low-temperature cracking resistance needs to be further improved. During the rejuvenation process of aged asphalt, the colloidal state changes from gel-state to sol-state, characterizing that the viscosity of asphalt decreased and the fluidity increased. Wood tar-based rejuvenator can react with aged asphalt to weaken the vibration strength of carbonyl and sulfoxide groups, so as to realize the recovery of service performance. Wood tar-based rejuvenator has better environmental protection and applicability, which is worthy of further study and promotion.

CORIOLIS VIBRATING GYROSCOPE WITH A METAL RESONATOR. DEVELOPMENT AND MANUFACTURING

Coriolis vibrating gyroscope (CVG) with cavity resonators are promising inertial angle and angular velocity sensors. Cavity resonators are sensitive elements of the CVG; they can be produced of quartz glass or metal. CVG with a metal resonator demonstrates high vibration resistance and vibration strength compared to a CVG with a quartz resonator. Therefore, a CVG with a metal resonator is more suitable for dynamic land, sea, and aerospace-based carriers. For these carriers based on a CVG with a metal resonator, measuring modules for orientation, stabilization and navigation systems of middle class accuracy can be made, comparable to similar systems using some types of fiber-optic and rotor vibration gyros. Preparing the production of a CVG with a metal resonator required solving the following tasks: developing control electronics, tuning and calibrating techniques for the given ranges of measuring the angular velocities of carriers in a wide temperature range, choosing a resonator material and working out the technological cycle of its manufacture taking into account mechanical and heat treatment. A series of research and development practices has been completed for the development of the resonator balancing technique that eliminates four forms of mass defect distribution. In the series production a CVG with a metal resonator having technical and operational characteristics that meet the technical conditions for its manufacturing was obtained. The dynamics features of a Coriolis vibrating gyroscope (CVG) with a metal resonator and the technology of its production have been considered. The technical characteristics of a CVG, manufactured by Michurinsky “Progress” plant, are given.