scholarly journals Experimental analysis of the dynamic responses of bridging objects with alternative non-contact method

2019 ◽  
Vol 110 ◽  
pp. 01028 ◽  
Author(s):  
Boštjan Kovačič ◽  
Tomaž Motoh ◽  
Samo Lubej
Keyword(s):  
Dynamic Response ◽  
Experimental Analysis ◽  
Technological Development ◽  
Dynamic Responses ◽  
Contact Method ◽  
Reliability Of Results ◽  
Constant Frequency ◽  
Regular Monitoring ◽  
State Of Art

Structure objects are exposed to different natural influences resulting in long-term and catastrophic outcomes. In order to avoid them, regular monitoring is needed. Various approaches to control condition of a structure can be considered, one of them is the measurement by means of monitoring which can be performed in different ways, depending on responses – static or dynamic, or both simultaneously. Specifically, technological development has enabled to monitor not only static but also dynamic responses by non-contact geodetic methods. Due to their simplicity and reliability of results, geodetic methods are more and more useful in this area. Moreover, state-of-art instruments and additional programme equipment allows up to 100 readings per second with an almost constant frequency of sampling, which is a condition for calculation of a dynamic response according to Fourier’s transformation. The article presents non-contact geodetic method of RTS on a bridging object.

Dynamic responses of community structure and microbial functions of periphytic biofilms during chronic exposure to TiO2 NPs

2020 ◽  
Vol 7 (2) ◽  
pp. 665-675 ◽  
Author(s):  
Jun Hou ◽  
Tengfei Li ◽  
Lingzhan Miao ◽  
Guoxiang You ◽  
Yi Xu ◽  
...  
Keyword(s):  
Community Structure ◽  
Dynamic Response ◽  
Chronic Exposure ◽  
Dynamic Responses ◽  
Tio2 Nps ◽  
Microbial Function

We investigated the dynamic response of community structure and microbial function of periphytic biofilms during long-term exposure to TiO2 NPs.

Secular stagnation in the modern world

2018 ◽  
pp. 125-141 ◽  
Author(s):  
S. M. Drobyshevsky ◽  
P. V. Trunin ◽  
A. V. Bozhechkova
Keyword(s):  
Public Debt ◽  
Capital Accumulation ◽  
Technological Development ◽  
Japanese Economy ◽  
Modern World ◽  
Key Factors ◽  
Destruction Process ◽  
Secular Stagnation ◽  
The Impact

The paper studies the factors of secular stagnation. Key factors of long-term slowdown in economic growth include the slowdown of technological development, aging population, human capital accumulation limits, high public debt, creative destruction process violation etc. The authors analyze key theoretical aspects of long-term stagnation and study the impact of these factors on Japanies economy. The authors conclude that most of the factors have significant influence on the Japanese economy for recent decades, but they cannot explain all dynamics. For Russia, on the contrary, we do not see any grounds for considering the decline in the economy since 2013 as an episode of secular stagnation.

3-D elastic coupling vibration and acoustical radiation characteristics of cracked gear under elastic support condition

2015 ◽  
Vol 23 (9) ◽  
pp. 1548-1568 ◽  
Author(s):  
Shao Renping ◽  
Purong Jia ◽  
Xiankun Qi
Keyword(s):  
Dynamic Response ◽  
Support System ◽  
Three Dimensional ◽  
Elastic Support ◽  
Dynamic Responses ◽  
Tooth Root ◽  
Support Condition ◽  
Elastic Boundary ◽  
Root Crack ◽  
Elastic Disc

According to the actual working condition of the gear, the supporting gear shaft is treated as an elastic support. Its impact on the gear body vibration is considered and investigated and the dynamic response of elastic teeth and gear body is analyzed. On this basis, the gear body is considered as a three-dimensional elastic disc and the gear teeth are treated as an elastic cantilever beam. Under the conditions of the elastic boundary (support shaft), combining to the elastic disk and elastic teeth, the influence of three-dimensional elastic discs on the meshing tooth response under an elastic boundary condition is also included. A dynamic model of the gear support system and calculated model of the gear tooth response are then established. The inherent characteristics of the gear support system and dynamics response of the meshing tooth are presented and simulated. It was shown by the results that it is correct to use the elastic support condition to analyze the gear support system. Based on the above three-dimensional elastic dynamics analysis, this paper set up a dynamics coupling model of a cracked gear structure support system that considered the influence of a three-dimensional elastic disc on a cracked meshing tooth under elastic conditions. It discusses the dynamic characteristic of the cracked gear structure system and coupling dynamic response of the meshing tooth, offering a three-dimensional elastic body model of the tooth root crack and pitch circle crack with different sizes, conducting the three-dimensional elastic dynamic analysis to the faulty crack. ANSYS was employed to carry out dynamic responses, as well as to simulate the acoustic field radiation orientation of a three-dimensional elastic crack body at the tooth root crack and pitch circle with different sizes.

Evaluation of the Dynamic-Response-Based Intact Stability Criterion for Floating Wind Turbines

2015 ◽  
Author(s):  
Marco Masciola ◽  
Xiaohong Chen ◽  
Qing Yu
Keyword(s):  
Wind Speed ◽  
Dynamic Response ◽  
Wind Turbines ◽  
Stability Criterion ◽  
Area Ratio ◽  
Operating Conditions ◽  
Dynamic Responses ◽  
Stability Criteria ◽  
Intact Stability ◽  
Overturning Moment

As an alternative to the conventional intact stability criterion for floating offshore structures, known as the area-ratio-based criterion, the dynamic-response-based intact stability criteria was initially developed in the 1980s for column-stabilized drilling units and later extended to the design of floating production installations (FPIs). Both the area-ratio-based and dynamic-response-based intact stability criteria have recently been adopted for floating offshore wind turbines (FOWTs). In the traditional area-ratio-based criterion, the stability calculation is quasi-static in nature, with the contribution from external forces other than steady wind loads and FOWT dynamic responses captured through a safety factor. Furthermore, the peak wind overturning moment of FOWTs may not coincide with the extreme storm wind speed normally prescribed in the area-ratio-based criterion, but rather at the much smaller rated wind speed in the power production mode. With these two factors considered, the dynamic-response-based intact stability criterion is desirable for FOWTs to account for their unique dynamic responses and the impact of various operating conditions. This paper demonstrates the implementation of a FOWT intact stability assessment using the dynamic-response-based criterion. Performance-based criteria require observed behavior or quantifiable metrics as input for the method to be applied. This is demonstrated by defining the governing load cases for two conceptual FOWT semisubmersible designs at two sites. This work introduces benchmarks comparing the area-ratio-based and dynamic-response-based criteria, gaps with current methodologies, and frontier areas related to the wind overturning moment definition.

Experimental and Numerical Analysis for Two Kinds of Impact Vibration of Gear

2011 ◽  
Vol 141 ◽  
pp. 43-48 ◽  
Author(s):  
Lin Yu Su ◽  
Yi Qiang Sun ◽  
Jian Ming Wen
Keyword(s):  
Numerical Analysis ◽  
Experimental Analysis ◽  
Dynamic Responses ◽  
Elastic Model ◽  
Motion Equations ◽  
Elastic Boundary ◽  
Mechanical Models ◽  
Impact Vibration ◽  
Dynamic Bifurcation ◽  
Impact Models

In this paper, there are two kinds of impact vibration models: rigid impact model and elastic model. The dynamic responses of the two kinds of gear impact models are compared by experimental and numerical analysis. Firstly, establish the motion equations of the two models. Secondly, verify the correctness of the mechanical models through experimental analysis. Comparing the results of the numerical and experimental analysis, we can find that the intensity noise of gear vibration is reduced by the elastic boundary. Finally, the dynamic bifurcation characteristic of dimensionless excitations magnitude and backlash will be analyzed as well.

PROSPECTS FOR THE DEVELOPMENT OF THE INNOVATIVE MARKET OF CHEMICAL TECHNOLOGIES IN RUSSIA

2021 ◽  
Author(s):  
Natalia Nikolaeva ◽  
Nikita Grinev ◽  
Pavel Barabanov ◽  
Elena Kulyuasova ◽  
Nikolay Kulyuasov
Keyword(s):  
Russian Federation ◽  
Chemical Industry ◽  
Technological Development ◽  
Global Market ◽  
The State ◽  
Economic Relations ◽  
Industrial Enterprises ◽  
Chemical Complex ◽  
The Russian Federation

"The transition of Russia to sustainable economic growth is impossible without stimulating the use of the achievements of science and education, high technologies, promoting innovative activity as an essential premise for the development of social production and subjects of economic relations. For the state, the promotion of innovation is a priority in the economic policy sector, since it is the level of scientific and technological development that largely determines the long-term strategic advantages of the country, and the prospects for the development of the state largely dependent on the level of innovation development. For a long time, the Ministry of Economic Development of the Russian Federation has been implementing the Strategy for Innovative Development of the Russian Federation. It includes 20 key steps and is developed based on the provisions of the concept of long-term development of the Russian Federation. The main results should have been, firstly, an increase in spending on science and innovation, and secondly, an increase in the share of industrial enterprises that introduce innovations in production. It was assumed that their share will increase by 4-5 times by 2020, compared with 2010 year. Not everything has been achieved, and there is a lot to strive for. This study is devoted to the driver of scientific and technological progress - the chemical complex of Russia. The chemical complex plays a significant role in the implementation of the most important socio-economic programs of the country. The study is devoted to the consideration of the most important prospects and key alternatives for the development of the chemical industry related to different areas of innovation. Conclusions will be made on key technologies and products that can change the position of the chemical industry in the global market."

Implementation of a Method for Free-Spanning Pipeline Analysis

2021 ◽  
Author(s):  
Joannes Gullaksen
Keyword(s):  
Dynamic Response ◽  
Flow Direction ◽  
Limit State ◽  
Cross Flow ◽  
Ultimate Limit State ◽  
Force Model ◽  
Short Term ◽  
Direct Wave ◽  
Current Loading

Abstract The scope of this paper is to provide a method implemented in an application for assessment of dynamic response of free spanning pipelines subjected to combined wave and current loading. The premises for the paper are based on application development within pipeline free span evaluation in a software development project. A brief introduction is provided to the basic hydrodynamic phenomena, principles and parameters for dynamic response of pipeline free spans. The choice of method for static and dynamic span modelling has an influence on calculated modal frequencies and associated stresses. Due to the importance of frequencies and stresses for fatigue and environmental loading calculations, the choice of analysis approach influences the partial safety factor format. The aim of the structural analysis is to provide the necessary input to the calculations of VIV and force model response, and to provide realistic estimations of static loading from functional loads. Environmental flow conditions are implemented in the application, such as steady flow due to current, oscillatory flow due to waves and combined flow due to current and waves. Combined wave and current loading include the long-term current velocity distribution, short-term and long-term description of wave-induced flow velocity amplitude and period of oscillating flow at the pipe level and return period values. Inline and cross-flow vibrations are considered in separate response models. For pipelines and risers, modes are categorized in in-line or cross-flow direction. A force model is also considered for the short-term fatigue damage due to combined current and direct wave actions. Design criteria can be specified for ultimate limit state (ULS) and fatigue limit state (FLS) due to in-line and cross-flow vortex induced vibrations (VIV) and direct wave loading.

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