Study on the Effect of Supporting Stiffness on Energy Dissipation Efficiency of Viscous Dampers

2011 ◽  
Vol 105-107 ◽  
pp. 96-101
Author(s):  
Yun Xiang Lu ◽  
Yuan Qi Cai ◽  
Qing Fei Qu ◽  
Qian Hua Zhan
Keyword(s):  
Energy Dissipation ◽  
Great Influence ◽  
Scientific Basis ◽  
Vibration Energy ◽  
Viscous Damper ◽  
Viscous Dampers ◽  
Main Research ◽  
Stiffness Design ◽  
Strength And Stiffness ◽  
Working Parameters

Viscous dampers are widely used in vibration energy dissipation project. The researches on viscous dampers used in energy dissipation project at present are more, and one of the main research contents is about how to improve energy dissipation efficiency. In the current study, the effect of the supporting stiffness in dampers is neglected, and only its strength and stiffness is verified. Based on the research on the principle and mechanical model of viscous damper, the influence of supporting stiffness on various energy dissipation working parameters has been analyzed in this paper. The results showed that, supporting stiffness has great influence on the energy dissipation efficiency, then with energy dissipation efficiency as the index, this paper derived the generality support stiffness design formula for energy consumption optimizing, which provide scientific basis for similar design.

scholarly journals The article is dedicated to the anniversary of Boris Vasilyevich Markov, the famous philosopher of Saint Petersburg, Russia. The author of the article, basing on many years of personal experience and professional communication with the hero of the day, presents an expressive and holistic image of Markov as a person and as a philosopher according to his biography and creativity. An attempt is made to consider the complex philosophical evolution of Markov, which took place in key periods for Russian philosophy when Russian thought actively absorbed the key philosophical texts of the 20th century that had become available. Markov is distinguished by a unique ability to creatively rethink a variety of philosophical trends — classical philosophical schools, phenomenology, existentialism, hermeneutics, analytical philosophy, structuralism — actualizing their significance for modern philosophy and synthesizing their experience in their original understanding. The specificity of Markov’s oral and written language is distinguished by its expressiveness, brightness and aphorism. It is no coincidence that the philosophy of language had a great influence on his philosophical development, remaining as one of the main research topics throughout all his works. Touching upon some of the key books of Professor Markov, written by him at different times, the author strives to briefly mention and analyze the main features of his philosophical style, thinking, and worldview. Special attention is paid to philosophical anthropology, which is directly related to the philosophical activity of the hero of the day over the past few decades. In this regard, emphasis is given to Markov’s book “Mind and Heart”, which marked the beginning of the most productive period of his philosophical work, which is currently associated with the problems of visual anthropology of communication.

2021 ◽  
Vol 37 (3) ◽  
pp. 393-402
Author(s):  
Boris I. Pruzhinin ◽  
Keyword(s):  
Philosophy Of Language ◽  
Great Influence ◽  
Scientific Basis ◽  
Social Contexts ◽  
Russian Philosophy ◽  
Self Awareness ◽  
Main Research ◽  
Expert Opinions ◽  
The Social ◽  
Philosophical Texts

The article examines the epistemological parameters of the phenomenon of expert examination as well as the social and cognitive features of using scientific knowledge to substantiate the objectivity of expert evaluations. Today, the scope of expert activities has significantly expanded. Accordingly, the number of studies, including philosophical ones, considering this phenomenon, in particular, has increased primarily in connection with the growth of its role in assessing the social-humanitarian risks associated with the introduction of scientific-technical advances. At the same time, attention is directed to the fact that it is precisely due to the significant expansion of the scope of expert activity that the nature of the expert examination itself is distorted — its dependence on social contexts is increasing, but its objectivity is lost. The article aims to clarify the reasons for the growth of this dependence in connection with the specificity of the epistemological parameters of knowledge, which is used as a scientific basis for expert evaluations. This aspect of expert examination, as a rule, falls out of sight of both its researchers and the experts themselves. Modern philosophers and methodologists of science state the direct dependence of expert examination on applied (i. e., limited to practical requests) developments, while, in the author’s opinion, the condition for the objectivity of expert opinions is the obligatory appeal of experts to fundamental science, motivated by the commitment to expand the sphere of holistic knowledge concerning the world. This condition is highlighted due to the epistemological perspective of comprehending expert evaluations, which makes it possible to include additional criteria for their objectivity in the sphere of the expert’s self-awareness. The actualization of such criteria, according to the author, is now becoming a prerequisite for an effective expert examination that maintains a high social status.

scholarly journals Optimisation of Longitudinal Seismic Energy Dissipation System for Straddle-type Monorail-Cum-Road Long-Span Cable-Stayed Bridge

2019 ◽  
Vol 2019 ◽  
pp. 1-16
Author(s):  
Xiong Liang ◽  
Baomu Li ◽  
Xiaolu Liu ◽  
Linong Liang
Keyword(s):  
Energy Dissipation ◽  
Seismic Energy ◽  
Viscous Damper ◽  
Viscous Dampers ◽  
Damping Effect ◽  
Cable Stayed Bridge ◽  
Long Span ◽  
Braking Force ◽  
Energy Dissipation System ◽  
Dissipation System

To investigate the optimal longitudinal seismic energy dissipation system of straddle-type monorail-cum-road long-span cable-stayed bridges, the Niutianyang Bridge was selected as the engineering background, and the explicit time-domain dimension-reduced iteration method was adopted to carry out nonlinear time-history analysis. To consider the dynamic characteristics of longitudinal movable supports, the static and dynamic responses of four kinds of energy dissipation systems were studied, including longitudinal unconstrained, elastic cable, viscous damper, and speed lock-up devices. The damping effect of four types of schemes in which viscous dampers were installed at piers or towers was analysed, and the parameters of the viscous dampers were optimised. The influences of the straddle-type monorail train braking force and the running vibration of the straddle-type monorail traffic on the parameters of the viscous dampers were analysed. This study shows that the viscous damper system had the lowest bending moment at the bottom of the tower and a smaller displacement response, and the energy dissipation was the best. Each viscous damper had the highest energy dissipation efficiency when they are installed only at the main tower. The damping effect was better when the damping coefficient c ranged from 3500 to 5000 kN⋅m/s−α and the velocity exponent α ranged from 0.35 to 0.5. The static friction of the straddle-type monorail-cum-road long-span cable-stayed bridge support can resist the trains’ braking force, and the parameters of the viscous damper can be selected regardless of train braking. A suitably large value of velocity exponent α may be required to increase the working velocity of the viscous damper to reduce the damper’s participation in the process of the train crossing the bridge.

In-Plane Vibration Damping of a U-Tube With Wet and Dry Flat-Bar Supports

2014 ◽  
Author(s):  
Paul A. Feenstra ◽  
Victor P. Janzen ◽  
Bruce A. W. Smith
Keyword(s):  
Energy Dissipation ◽  
Plane Motion ◽  
Test Facility ◽  
Vibration Energy ◽  
Test Rig ◽  
Two Phase ◽  
Support Conditions ◽  
Vibration Tests ◽  
Energy Dissipated ◽  
Steam Generator Tubes

Tests are being planned which will use AECL’s MR-3 Freon test facility and a Multi-Span U-Bend (MSUB) test rig to investigate the dynamics of tube vibration in two-phase flow, in particular those mechanisms that can cause excessive damage to steam-generator tubes. In preparation for the tests, free- and forced-vibration tests were conducted to measure the vibration energy dissipation (damping) of a single U-bend tube in air, with dry and wet anti-vibration bars, under a variety of tube-support conditions. This paper presents the relevant damping mechanisms and documents methods used to conduct the tests and to analyze the energy dissipated at the supports. Results indicate that for in-plane motion without tube-to-support contact, viscous damping related to wet AV B supports is much smaller than guidelines based on other types of supports suggest. To begin to examine the effects of the tube coming into contact with its supports, such as friction-related energy dissipation, the results of tests with light tube-to-support preloads are also presented.

scholarly journals VIBRATION ENERGY DISSIPATION OF A COMPOSITE MATERIAL/KOMPOZICINĖS MEDŽIAGOS VTRPESIŲ ENERGIJOS DISIPACIJA

1998 ◽  
Vol 4 (4) ◽  
pp. 280-282
Author(s):  
Petras Baradokas
Keyword(s):  
Composite Material ◽  
Energy Dissipation ◽  
Strain Energy ◽  
Vibration Energy ◽  
Separate Component ◽  
Dissipation Coefficient ◽  
Energy Dissipation Coefficient

The paper discusses the problem of evaluating vibration energy dissipation of a composite material. It is suggested to express the dissipation cofficient in a line (2). The reduced component dissipation coefficients c i φi are the members of the line. The ratio of reduction c i , shows the proportion by which a separate component adds to the energy dissipation of the entire composition. By analysing the accumulated and dissipated strain energy of a composite material were obtained (6). On the basis of these expressions, formulas for calculating the dissipation coefficients of a three-layer bar and that with a galvanic covering were devised. The analysis made leads to the following conclusions: - the vibration energy dissipation coefficient of a composite material is equal to the sum of the reduced dissipation coefficients of the composition component materials; - the ratio of reduction c i depends on the value of the component accumulated energy; - for comparing separate components as to the energy dissipation, the product φ i E i should be used.

Seismic Reduction and Control Analysis of Hybrid Structure with Viscous Dampers under Strong Earthquake

2014 ◽  
Vol 580-583 ◽  
pp. 1633-1636 ◽  
Author(s):  
Sen Qiu ◽  
Shu Cheng Deng ◽  
Zhao Quan Zhu
Keyword(s):  
Strong Earthquake ◽  
Lateral Displacement ◽  
Hybrid Structure ◽  
Earthquake Ground Motion ◽  
Control Analysis ◽  
Viscous Damper ◽  
Viscous Dampers ◽  
Maximum Value ◽  
Story Drift ◽  
And Control

This article focuses on the effect of viscous damper on seismic performance of steel-concrete hybrid structure under strong earthquake. The result shows that viscous damper has effect on seismic reduction and control. The story lateral displacement, story drift rotation and energy dissipation-seismic can be reduced effectively by viscous dampers. The maximum value of vibration-reduction ratio is 36.0%, 67.9%, 36.9%. It is different effect on seismic reduction by different earthquake ground motion. Response of earthquake amplifies under Pasadena earthquake wave than the others.

Investigation of the effects of silicone emulsions having different particle sizes on knitted fabrics depending on the type of yarn

2017 ◽  
Vol 29 (3) ◽  
pp. 394-416 ◽  
Author(s):  
Burcu Sancar Besen ◽  
Onur Balci
Keyword(s):  
Future Research ◽  
Particle Sizes ◽  
Knitted Fabrics ◽  
Content Type ◽  
Bursting Strength ◽  
Chemical Structures ◽  
Strength And Stiffness ◽  
Ring Open ◽  
Working Parameters ◽  
Physical And Chemical

Purpose The purpose of this paper is to investigate the effects of silicone-based softeners, which were developed with different particle sizes (nano, micro, and macro) and chemical structures, on the performance of 100 percent cotton fabrics knitted with different type of yarn (ring, open-end, and compact). Design/methodology/approach In the study, the silicone emulsions having expected particle sizes were produced at laboratory conditions. The produced silicone emulsions were applied to knitted fabrics with both padding and exhaust methods at different concentrations. Some characterization tests (particle size and zeta potential) were applied to the silicone emulsions before the applications. After the applications, CIELab values, whiteness and color fastness, hyrophility, abrasion, pilling, bursting strength, and stiffness performances of the samples were tested. The changes of the investigated properties were also examined via ANOVA. Findings According to the results, it was found that the silicone applications caused the CIELab values, whiteness degree, hyrophility, pilling, bursting strength and stiffness performance of the fabrics to change depending on the particle sizes of the emulsions, the yarn type of the fabrics, the application type, and the concentration of the silicone emulsions. When the ANOVA results were examined, it was seen that the types of the yarn and the silicone emulsions were the most effective working parameters on the results. Research limitations/implications Because no additives were added to the produced silicone emulsions, in the future research, they can be developed with the use of some additives. Thus, it can resolve some of the disadvantages of the silicone emulsions on the textiles. Practical implications While applying the silicone softeners to the knitted fabrics, the type of the yarn and the particle sizes of the emulsions must be determined according to each other, in order to obtain enough handle performance without causing negative change on the other important properties of the knitted fabrics. Originality/value When the studies regarding silicone softeners were investigated, it was found that there were no studies about the effect of the silicone softeners having different particle sizes on the physical and chemical structures of the knitted fabrics depending on the type of yarn and some working parameters such as concentration and type of the application.

Experimental study on the seismic performance of traditional timber mortise-tenon joints with different looseness under low-cyclic reversed loading

2018 ◽  
Vol 22 (6) ◽  
pp. 1312-1328 ◽  
Author(s):  
Jianyang Xue ◽  
Rui Guo ◽  
Liangjie Qi ◽  
Dan Xu
Keyword(s):  
Energy Dissipation ◽  
Seismic Performance ◽  
Failure Modes ◽  
Artificial Defect ◽  
Reversed Loading ◽  
Energy Dissipation Capacity ◽  
Strength And Stiffness ◽  
Seismic Behaviors ◽  
Damage Type ◽  
Better Than

The majority of existing ancient timber structures have different degrees of damage. The looseness of mortise-tenon joints is a kind of typical damage type. In order to study the influence of looseness on the seismic performance of mortise-tenon joints, six through-tenon joints and six dovetail-tenon joints with scale 1:3.2 were fabricated according to the requirements of the engineering fabrication method of Chinese Qing Dynasty. Each type of joints consisted of one intact joint and five artificial loose joints, and the artificial defect was made to simulate looseness by cutting the tenon sectional dimension. Based on experiments of two types of joints under low-cyclic reversed loading, the seismic behaviors of joints such as failure modes, hysteretic loops and skeleton curves, strength and stiffness degradation, and energy dissipation capacity were studied. Moreover, the comparative analyses of seismic performance between two types of joints were carried out. The variation tendency of seismic behaviors of two types of joints has similarities, and there are some differences due to their different structural styles. The results indicate that squeeze deformation between tenon and mortise of two types of joints occurred. The shape of hysteretic loops of two types of joints is reverse-Z-shape, and the pinching effect of hysteretic loops becomes more obvious with the increase in looseness, among which of through-tenon joints is more obvious than that of dovetail-tenon joints. The carrying capacity, stiffness, and energy dissipation capacity of loose joints are significantly lower than that of the intact one, and the energy dissipation capacity of dovetail-tenon joints is better than that of through-tenon joints. The rotation angles of two types of joints can reach 0.12 rad, and the loose joints still have great deformation capacity.

scholarly journals Retrofit Existing Frame Structures to Increase Their Economy and Sustainability in High Seismic Hazard Regions

2019 ◽  
Vol 9 (24) ◽  
pp. 5486 ◽  
Author(s):  
Shuang Li ◽  
Jintao Zhang
Keyword(s):  
Optimum Design ◽  
Computational Cost ◽  
Time History ◽  
Economic Benefits ◽  
Frame Structure ◽  
Viscous Damper ◽  
Viscous Dampers ◽  
Frame Model ◽  
Rare Earthquake ◽  
Original Frame

The study proposes a retrofitting method with an optimum design of viscous dampers in order to improve the structural resistant capacity to earthquakes. The retrofitting method firstly uses a 2D frame model and places the viscous dampers in the structure to satisfy the performance requirements under code-specific design earthquake intensities and then performs an optimum design to increase the structural collapse-resistant capacity. The failure pattern analysis and fragility analysis show that the optimum design leads to better performance than the original frame structure. For regular structures, it is demonstrated that the optimum pattern of viscous damper placement obtained from a 2D frame model can be directly used in the retrofitting of the 3D frame model. The economic loss and repair time analyses are conducted for the retrofitted frame structure under different earthquake intensities, including the frequent earthquake, the occasional earthquake, and the rare earthquake. Although the proposed method is based on time-history analyses, it seems that the computational cost is acceptable because the 2D frame model is adopted to determine the optimum pattern of viscous damper placement; meanwhile, the owner can clearly know the economic benefits of the retrofitting under different earthquake intensities. The retrofitting also causes the frame to have reduced environmental problems (such as carbon emission) compared to the original frame in the repair process after a rare earthquake happens.

scholarly journals Study on the Damping Effect of Particle Dampers considering Different Surface Properties

2019 ◽  
Vol 2019 ◽  
pp. 1-16
Author(s):  
Xiaowei Li ◽  
Yue Yang ◽  
Weixing Shi
Keyword(s):  
Energy Dissipation ◽  
Surface Property ◽  
Material Selection ◽  
Great Influence ◽  
Contact Theory ◽  
Theoretic Model ◽  
The Finite Element Method ◽  
Particle Damping ◽  
Vibration Experiment ◽  
Particle Dampers

Particle dampers are nonlinear vibration control devices. The surface property has a great influence on the performance of the particle damper, but it is difficult to be considered and analyzed. This paper firstly gives a view of how to establish a theoretic model of the particle damper. The dynamic equation and energy dissipation coefficient of collision are revised from the Hertz contact theory in the proposed theoretic model, considering the friction of particles. Then, a contrastive collision model relying on the finite element method is established to verify the reasonability of the theoretic model. The effects of different factors which will have an influence on the performance of the particle damper are discussed, and several conclusions on how to optimize the particle damper are proposed. Except for the aforementioned dynamic analysis, this paper also presents a particle damping index to evaluate the capability of energy dissipation of different materials, in order to facilitate the material selection in the practical design. Finally, an experiment is developed to verify the character of the collision and energy dissipation. The feasibility of the proposed method to estimate the surface property of different particles is validated by the free vibration experiment.

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