Study of Cycloidal Pendulum Dynamic Absorber for Vibration Control of Structures

2006 ◽  
Author(s):  
Toshihiko Komatsuzaki ◽  
Yoshio Iwata
Keyword(s):  
Vibration Control ◽  
Natural Frequency ◽  
Experimental Investigations ◽  
Practical Application ◽  
Pendulum System ◽  
Optimal Damping ◽  
Intrinsic Nonlinearity ◽  
New Type ◽  
Dynamic Absorber ◽  
And Performance

The dynamic absorber has been widely used for suppressing vibration in structures. In practical application, the optimal tuned absorbers are designed and used in terms of natural frequency and additional damping so that resultant frequency response may become fully reduced. Among various types of dynamic absorber, the pendulum type is preferable due to its simple constitution and performance reliability. However, damping performance of ordinal pendulum system may be influenced by levels of excitation because of intrinsic nonlinearity in system which leads to slight change in natural frequency. The present paper deals with a study of new type pendulum dynamic absorber. It is known that pendulum moving along cycloidal curve strictly keeps uniform period. Both analytical and experimental investigations show that a strict optimal damping condition can be satisfied in cycloidal pendulum damper, in conjunction with better damping performance compared with normal pendulum.

scholarly journals On practical application of Zubov’s optimal damping concept

2020 ◽  
Vol 16 (3) ◽  
pp. 293-315
Author(s):  
Evgeny I. Veremey ◽  
Keyword(s):  
Practical Implementation ◽  
Optimization Approach ◽  
Practical Application ◽  
Closed Loop System ◽  
Control Laws ◽  
Optimal Damping ◽  
New Ideas ◽  
And Performance ◽  
Essential Connection ◽  
Significant Attention

This article presents some new ideas connected to nonlinear and nonautonomous control laws based on the application of an optimization approach. There is an essential connection between practical demands and the functionals to be minimized. This connection is at the heart of the proposed methods. The discussion is focused on the optimal damping concept first proposed by V. I. Zubov in the early 1960’s. Significant attention is paid to various modern aspects of the optimal damping theory’s practical implementation. Emphasis is given to the specific choice of the functional to be damped to provide the desirable stability and performance features of a closed-loop system. The applicability and effectiveness of the proposed approach are confirmed by an illustrative numerical example.

scholarly journals Dynamic absorber for ropeway gondola using Coriolis force

2008 ◽  
Vol 30 (4) ◽  
Author(s):  
Hiroshi Matsuhisa ◽  
Masashi Yasuda
Keyword(s):  
Natural Frequency ◽  
Coriolis Force ◽  
Large Amplitude ◽  
Theoretical Predictions ◽  
New Type ◽  
Small Model ◽  
Dynamic Absorber

Wind-induced swinging of ropeway gondola can be reduced using dynamic absorbers. To maximize the performance of conventional dynamic absorbers, their location should be as high as possible. However, absorbers can not be installed at high positions due to interference issues with structures such as towers and stations. To address this problem, a new type of dynamic absorber that moves vertically is proposed. This absorber is composed of a mass supported by a spring. The mass moves in the radius direction (up and down) and it induces Coriolis force in the circumference direction to prevent the swing of gondola. If the natural frequency of the absorber is tuned to twice that of the gondola, the absorber moves spontaneously with a large amplitude due the resonance. This absorber is more effective when it is located at lower positions. The experiment with a small model and an actual gondola for 10 passengers were carried out and the results agreed well with the theoretical predictions.

Integrated Dynamic Characteristics and Application in Semi-Active Dynamic Absorber of Magneto-Rheological Fluids

2012 ◽  
Vol 220-223 ◽  
pp. 601-606
Author(s):  
Shi Zhen Li ◽  
Gong Yu Li ◽  
Xiao Wu Kong ◽  
Jian Hua Wei
Keyword(s):  
Natural Frequency ◽  
Dynamic Characteristics ◽  
Damping Ratio ◽  
Dynamic Test ◽  
Shear Mode ◽  
Vibration Absorption ◽  
New Type ◽  
Dynamic Absorber ◽  
Magneto Rheological ◽  
Squeeze Effect

As a new type of controllable rheological smart material, Magneto-rheological Fluids (MRF) are widely used in the field of vibration control. This article investigated their integrated dynamic characteristics in squeeze mode and shear mode. Two prototypes were designed and fabricated. The dynamic test for the two prototypes was performed on a simply supported beam vibrating device with the methods of drop-hammering and sweep-frequency measuring. The experimental results demonstrate that the damping ratio of the prototype in squeeze effect presents linearly and widely controllable from 0.0948 to 0.2268 with the increase of the coils’ excitation current, behaving as a variable MR damper. However, its natural frequency remains unchanged. It is also shown that the natural frequency of the prototype in shear effect increases significantly from 18Hz to 24 Hz, acting as a semi-active dynamic vibration (SDVA) absorber with broadband vibration absorption for the maximum attenuation of up to 74.3%. This study provides guidance for engineering applications of MRF.

scholarly journals Direction for the program for abusers or probation program: a practical aspect

2021 ◽  
pp. 24-28
Author(s):  
Tetiana NIKIFOROVA
Keyword(s):  
Domestic Violence ◽  
Criminal Law ◽  
Criminal Code ◽  
Practical Aspect ◽  
Local State ◽  
Practical Application ◽  
Restrictive Measure ◽  
New Type ◽  
And Performance ◽  
Restrictive Measures

Introduction. Restrictive measures applied to perpetrators of domestic violence are a relatively new type of criminal law measure provided for in current criminal law. The legislative and scientific novelty of these measures, the inconsistency norms of legislative acts, which regulate the procedure for their appointment and implementation, cause problems and difficulties in their practical application. Purpose. Analysis of the practice of restrictive measures provided for in paragraph 5 of Part 1 of Art. 91-1 of the Criminal code of Ukraine, revealing of problems and difficulties of their appointment and performance and statement of offers concerning possible overcoming of these problems, by elimination of legislative gaps and contradictions. Results. The article analyzes the practice of prescribing and implementing such restrictive measures applicable to perpetrators of domestic violence as "direction for program for abusers" and "direction for probation program". Problems and difficulties that arise due to the ambiguity of the wording of criminal law, the inconsistency of regulations governing the appointment and implementation of relevant measures, as well as the lack of professionalism of the judges. In particular, it was established that the judges did not specify which restrictive measure provided for in paragraph 5 of Part 1 of Article 91-1 of the Criminal Code of Ukraine should be applied to the convict, because it contains two different in content and procedure. This makes it impossible to enforce the sentence. Also, the lack of a mechanism for interaction of probation authorities with local state administrations and local self-government authorities makes it impossible for probation authorities to exercise control over convicts who are sent to undergo a program for abusers. Conclusion. It is proposed to amend Art. 91-1 of the Criminal code of Ukraine, the Law of Ukraine "About probation" and other regulatory legal acts, for the purpose of elimination of the analyzed problems of application of restrictive measures.

scholarly journals Ship Handling in Unprotected Waters: A Review of New Technologies in Escort Tugs to Improve Safety

2021 ◽  
Vol 2 (1) ◽  
pp. 46-62
Author(s):  
Santiago Iglesias-Baniela ◽  
Juan Vinagre-Ríos ◽  
José M. Pérez-Canosa
Keyword(s):  
High Performance ◽  
New Technologies ◽  
Weather Conditions ◽  
Hull Form ◽  
Best Available Technologies ◽  
Adverse Weather Conditions ◽  
Adverse Weather ◽  
New Type ◽  
Technological Challenge ◽  
And Performance

It is a well-known fact that the 1989 Exxon Valdez disaster caused the escort towing of laden tankers in many coastal areas of the world to become compulsory. In order to implement a new type of escort towing, specially designed to be employed in very adverse weather conditions, considerable changes in the hull form of escort tugs had to be made to improve their stability and performance. Since traditional winch and ropes technologies were only effective in calm waters, tugs had to be fitted with new devices. These improvements allowed the remodeled tugs to counterbalance the strong forces generated by the maneuvers in open waters. The aim of this paper is to perform a comprehensive literature review of the new high-performance automatic dynamic winches. Furthermore, a thorough analysis of the best available technologies regarding towline, essential to properly exploit the new winches, will be carried out. Through this review, the way in which the escort towing industry has faced this technological challenge is shown.

scholarly journals Experimental investigations on diesel engine using alumina nanoparticle fuel additive

2021 ◽  
Vol 13 (2) ◽  
pp. 168781402098840
Author(s):  
Mohammed S Gad ◽  
Sayed M Abdel Razek ◽  
PV Manu ◽  
Simon Jayaraj
Keyword(s):  
Diesel Engine ◽  
Diesel Fuel ◽  
Alumina Nanoparticles ◽  
Experimental Investigations ◽  
Fuel Additive ◽  
Alumina Nanoparticle ◽  
Fuel Injectors ◽  
Performance And Emission ◽  
And Performance ◽  
The Impact

Experimental work was done to examine the impact of diesel fuel with alumina nanoparticles on combustion characteristics, emissions and performance of diesel engine. Alumina nanoparticles were mixed with crude diesel in various weight fractions of 20, 30, and 40 mg/L. The engine tests showed that nano alumina addition of 40 ppm to pure diesel led to thermal efficiency enhancement up to 5.5% related to the pure diesel fuel. The average specific fuel consumption decrease about neat diesel fuel was found to be 3.5%, 4.5%, and 5.5% at dosing levels of 20, 30, and 40 ppm, respectively at full load. Emissions of smoke, HC, CO, and NOX were found to get diminished by about 17%, 25%, 30%, and 33%, respectively with 40 ppm nano-additive about diesel operation. The smaller size of nanoparticles produce fuel stability enhancement and prevents the fuel atomization problems and the clogging in fuel injectors. The increase of alumina nanoparticle percentage in diesel fuel produced the increases in cylinder pressure, cylinder temperature, heat release rate but the decreases in ignition delay and combustion duration were shown. The concentration of 40 ppm alumina nanoparticle is recommended for achieving the optimum improvements in the engine’s combustion, performance and emission characteristics.

The Research and Simulation Analysis of a New Type of Translational Transmission Device

2014 ◽  
Vol 556-562 ◽  
pp. 1408-1412
Author(s):  
Zhi Qiang Zhang
Keyword(s):  
Modeling And Simulation ◽  
Theoretical Foundation ◽  
Simulation Analysis ◽  
Structural Modeling ◽  
Structural Features ◽  
Practical Application ◽  
Optimization Analysis ◽  
New Type ◽  
Mechanism Parameter ◽  
Relationship Of

In this paper, the following work is done: a new type of translational transmission device is designed; explained in detail are the operating principle, structural features, relationship of mechanism parameter and non interference conditions of the movement; the optimization analysis of transmission device is implemented on the basis of non interference conditions of the bucket movement; structural modeling and simulation analysis are carried out by utilization of Pro/e & Recurdyn; and based on virtual prototype technology, the new type of translational transmission device is verified by experiments, the data of which prove the translational transmission device reasonable and practicable. In conclusion, this paper has laid the theoretical foundation of the practical application of the translational transmission device.

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