On the problem of using the bridge span as a tuned mass damper of bridge pier oscillation

2019 ◽  
pp. 24-30
Author(s):  
Olga Nesterova
Keyword(s):  
Critical Mass ◽  
Practical Importance ◽  
Tuned Mass Damper ◽  
Bridge Pier ◽  
Bridge Piers ◽  
Optimal Parameters ◽  
Bridge Span ◽  
Mass Damper ◽  
Effective Use ◽  
The Impact

Objective: To identify the area of effective use of bridge span as a tuned mass damper of bridge pier oscillation during earthquake in seismic areas. Methods: Numerical simulation of oscillations of the “bridge pier with span” system under both the impact set by the harmonic rule and the records of past earthquake accelerograms. Results: The area of effective use of bridge span structures as a tuned mass damper of bridge piers’ oscillation during earthquake in seismic areas has been defined. The concept of the relative critical mass of the span used as a tuned mass damper of bridge piers’ oscillation during earthquake has been introduced. When the spun structure mass reaches the critical value, the effect of the tuned mass damper disappears. The dependences of the optimal parameters of the connection between the span and pier on the relative span mass used as a tuned mass damper have been obtained. It has been found that the span critical mass used as a tuned mass damper decreases when the pier damping increases, and the dependences of the optimal parameters of the connection between the span structure and the pier on the damping in the pier body have been obtained. Practical importance: The possibility of using span as a tuned mass damper of piers is shown. The optimum characteristics of the span and its connection with the pier body have been obtained to be used in designing. The use of span as a tuned mass damper in piers can significantly reduce labor input and the cost of bridge building in seismic areas. It also facilitates the elimination of consequences of devastating earthquakes.

Determination of optimal parameters of the tuned mass damper to reduce the torsional vibration of the shaft by using the principle of minimum kinetic energy

2018 ◽  
Vol 233 (2) ◽  
pp. 327-335 ◽  
Author(s):  
Duy-Chinh Nguyen
Keyword(s):  
Kinetic Energy ◽  
Torsional Vibration ◽  
Damping Ratio ◽  
Vibration Reduction ◽  
Tuned Mass Damper ◽  
Optimal Parameters ◽  
Lagrangian Equations ◽  
Tuning Ratio ◽  
Mass Damper

In this paper, an analytical method is presented to determine the optimal parameters of the symmetric tuned mass damper, such as the ratio between natural frequency of tuned mass damper and shaft (tuning ratio) and the ratio of the viscous coefficient of tuned mass damper (damping ratio). The optimal parameters of tuned mass damper are applied to reduce the torsional vibration of the shaft based on consideration of the vibration duration and stability criterion. The dynamic equations of the shaft are provided via Lagrangian equations, and the optimal parameters of tuned mass damper are derived by using the principle of minimum kinetic energy. Analytical and numerical examples are implemented to verify the reliability of the proposed method. The analytical and numerical results indicate that the optimal parameters of tuned mass damper have significant effects in the torsional vibration reduction of the shaft.

scholarly journals Analysis of Water Flow Pressure on Bridge Piers considering the Impact Effect

2015 ◽  
Vol 2015 ◽  
pp. 1-8
Author(s):  
Yin-hui Wang ◽  
Yi-song Zou ◽  
Lue-qin Xu ◽  
Zheng Luo
Keyword(s):  
Water Flow ◽  
Coupling Effect ◽  
Highway Bridges ◽  
Element Model ◽  
Bridge Pier ◽  
Bridge Piers ◽  
Water Current ◽  
Fluid Structure ◽  
Impact Effect ◽  
The Impact

In order to investigate the effects of water current impact and fluid-structure interaction on the bridge piers, the mechanism of water flow impact on the bridge pier is firstly studied. Then a finite element model of a bridge pier is established including the effects of water flow impact as well as the water circumferential motion around the pier. Comparative study is conducted between the results of water impact effect, fluid-structure coupling effect, theoretical analysis, and also the results derived using the formulas specified in the design codes home and abroad. The results show that the water flow force calculated using the formulas provided by the codes should be multiplied by an impact amplifier to account for the effect of flood impact on the bridge pier. When the flood flows around the pier, the fluid-structure coupling effect on the bridge pier can be neglected. The method specified in the China guidelines ofGeneral Code for Design of Highway Bridges and Culvertstends to provide a larger result of the water flow force.

scholarly journals Effect of Seawater Exposure on Impact Damping Behavior of Viscoelastic Material of Pounding Tuned Mass Damper (PTMD)

2019 ◽  
Vol 9 (4) ◽  
pp. 632 ◽  
Author(s):  
Peng Zhang ◽  
Devendra Patil ◽  
Siu Ho
Keyword(s):  
Energy Dissipation ◽  
Viscoelastic Material ◽  
Hysteresis Loops ◽  
Tuned Mass Damper ◽  
Control Device ◽  
Impact Behavior ◽  
Lateral Impact ◽  
Experimental Apparatus ◽  
Mass Damper ◽  
The Impact

The pounding tuned mass damper (PTMD) is a novel vibration control device that can effectively mitigate the undesired vibration of subsea pipeline structures. Previous studies have verified that the PTMD is more effective and robust compared to the traditional tuned mass damper. However, the PTMD relies on a viscoelastic delimiter to dissipate energy through impact. The viscoelastic material can be corroded by the various chemical substances dissolved in the seawater, which means that there can be possible deterioration in its mechanical property and damping ability when it is exposed to seawater. Therefore, we aim to conduct an experimental study on the impact behavior and energy dissipation of the viscoelastic material submerged in seawater in this present paper. An experimental apparatus, which can generate and measure lateral impact, is designed and fabricated. A batch of viscoelastic tapes are submerged in seawater and samples will be taken out for impact tests every month. Pounding stiffness, hysteresis loops and energy dissipated per impact cycle are employed to characterize the impact behavior of the viscoelastic material. The experimental results suggest that the seawater has little influence on the behavior of the viscoelastic tapes. Even after continuous submersion in seawater for 5 years, the pounding stiffness and energy dissipation remains at the same level.

scholarly journals Seismic and Wind Analysis of Regular and Irregular RC Structures with Tuned Mass Damper

2019 ◽  
Vol 8 (3) ◽  
pp. 2263-2269
Keyword(s):  
Damping Ratio ◽  
Time History ◽  
Tuned Mass Damper ◽  
Ground Movement ◽  
Building Structures ◽  
Rc Structures ◽  
Dynamic Forces ◽  
Mass Damper ◽  
Rc Building ◽  
The Impact

Latest trend in the development high rise structure demanding taller and lighter structures, which are progressively adaptable with very low damping ratio. As the structures developing vertically, they are ending up all the more affecting by powerful excitation forces, for example, wind and seismic forces. For the more safety of structure and inhabitant's solace, the vibrations of the tall structures become a major issue for both structural designers. So as to control the vibration, various methodologies are proposed out of the few systems accessible for vibration control. Out of numerous methods, TMD has been observed to be increasingly powerful in controlling the dynamic forces caused due to seismic and wind excitations. In this paper, the adequacy of TMD in controlling the dynamic reaction of structures and the impact of different ground movement parameters on the seismic viability of TMD is researched. Essentially, a TMD is a vibratory subsystem appended to a bigger scale host structure so as to lessen the dynamic reactions. The frequency of damper will tuned to essential structure's frequency, so when frequency is high, the damper will results to resonate out of phase along with structural movement. The objective of this work is to study the impact of TMD on the dynamic forces brought about by seismic tremor and wind excitations in standard just as unpredictable in tall RC building structures. For that three 22 story RC building structures are considered with a similar arrangement out of which one ordinary regular structure and the other two are irregular RC structures are demonstrated in Etabs. In irregular RC structures, Stiffness irregularity and torsional irregularity are considered. For assessing seismic and wind reactions of structures, time history analysis, and static analysis used, with and without the tuned mass damper in ETABS. The outcomes acquired from the investigation of three 22 story RC structures with and without tuned mass damper are compared

scholarly journals Effect of Soil and Structure Nonlinear Interaction on the Efficiency of Tuned Mass Damper

2018 ◽  
Vol 4 (10) ◽  
pp. 2474
Author(s):  
Hamid Masaeli ◽  
Mehdi Panahi
Keyword(s):  
Nonlinear Interaction ◽  
Ground Motions ◽  
Time History ◽  
Tuned Mass Damper ◽  
Winkler Foundation ◽  
Optimal Parameters ◽  
Moment Frame ◽  
Mass Damper ◽  
Hard Soil ◽  
Bearing System

In this paper, three 10, 15, and 20-story two-dimensional concrete structures have been used with a moment frame bearing system as models under analysis. First, using various time history analyses by the OpenSees software, the optimal parameters of the tuned mass damper (TMD), including frequency and mass, were obtained. Structures controlled with and without TMD were modelled on three soft, moderate, and hard soil types classified according to Code 2800. The models were analyzed in terms of time history by 7 ground motions. In order to take into account the nonlinear interaction of soil and structure, the model of the beam on nonlinear Winkler foundation has been used. The results show that nonlinear interaction in most cases reduces the efficiency of TMD. Moreover, as the soil becomes softer, the efficiency reduction of the mass damper increases.

scholarly journals Experimental Study on Vibration Control of Suspended Piping System by Single-Sided Pounding Tuned Mass Damper

2019 ◽  
Vol 9 (2) ◽  
pp. 285 ◽  
Author(s):  
Jie Tan ◽  
Siu Michael Ho ◽  
Peng Zhang ◽  
Jinwei Jiang
Keyword(s):  
Free Vibration ◽  
Forced Vibration ◽  
Cost Effective ◽  
Tuned Mass Damper ◽  
Spring Steel ◽  
Piping System ◽  
Mass Damper ◽  
Piping Systems ◽  
High Flexibility ◽  
The Impact

Suspended piping systems often suffer from severe damages when subjected to seismic excitation. Due to the high flexibility of the piping systems, reducing their displacement is important for the prevention of damage during times of disaster. A solution to protecting piping systems during heavy excitation is the use of the emerging pounding tuned mass damper (PTMD) technology. In particular, the single-sided PTMD combines the advantages of the tuned mass damper (TMD) and the impact damper, including the benefits of a simple design and rapid, efficient energy dissipation. In this paper, two single-sided PTMDs (spring steel-type PTMD and simple pendulum-type PTMD) were designed and fabricated. The dampers were tested and compared with the traditional TMD for mitigating free vibration and forced vibration. In the free vibration experiment, both PTMDs suppressed vibrations much faster than the TMD. For the forced vibration test, the frequency response of the piping system was obtained for three conditions: without control, with TMD control, and with PTMD control. These novel results demonstrate that the single-sided PTMD is a cost-effective method for efficiently and passively mitigating the vibration of suspended piping systems. Thus, the single-sided PTMD will be an important tool for increasing the resilience of structures as well as for improving the safety of their occupants.

Design of the symmetric tuned mass damper for torsional vibration control of the rotating shaft

2021 ◽  
pp. 095745652110004
Author(s):  
Duy-Chinh Nguyen
Keyword(s):  
Angular Velocity ◽  
Vibration Control ◽  
Fixed Points ◽  
Torsional Vibration ◽  
Tuned Mass Damper ◽  
Constant Angular Velocity ◽  
Optimal Parameters ◽  
Rotating Shaft ◽  
Mass Damper

The shaft is one of the most important parts of the machine, and it is used to transmit torque. However, the shaft does not always rotate at constant angular velocity due to sudden acceleration or deceleration or due to unstable current. The rotation of the shaft varies with time, which causes torsional vibration on the rotating shaft. To the best of the author’s knowledge, there is no study on designing a symmetric tuned mass damper (STMD) for the rotating shaft with variable angular velocity. Therefore, the purpose of this study is to design an optimal STMD to reduce torsional vibration for the rotating shaft with variable angular velocity. First, the author designs an optimal STMD for the rotating shaft by the fixed-points theory. Second, the optimal parameters of the STMD are obtained by using the minimum quadratic torque method. The optimal parameters of the STMD are defined in analytic and explicit forms, helping researchers to easily design an optimal STMD when applying to reduce torsional vibration for the rotating shaft. Finally, to evaluate the reliability of the designed optimal STMD, Maple software is used to simulate the vibration of the rotating shaft attached with the optimal STMD, as well as to help the readers to have a visual view on the effect of reducing torsional vibration of the rotating shaft.

scholarly journals The impact of bridge pier on ice jam evolution – an experimental study

2016 ◽  
Vol 64 (1) ◽  
pp. 75-82 ◽  
Author(s):  
Jun Wang ◽  
Jian Hua ◽  
Jueyi Sui ◽  
Peng Wu ◽  
Tao Liu ◽  
...  
Keyword(s):  
Thickness Distribution ◽  
Early Spring ◽  
Bridge Pier ◽  
Bridge Piers ◽  
Ice Jam ◽  
Laboratory Flume ◽  
Different Diameters ◽  
Hydraulic Process ◽  
Different Characteristics ◽  
The Impact

AbstractThe ice jam in a river can significantly change the flow field in winter and early spring. The presence of bridge piers further complicates the hydraulic process by interacting between the ice jam and bridge piers. Using the data collected from experiments in a laboratory flume, the evolution of an ice jam around bridge piers having three different diameters has been investigated in this study. Compared to results without-pier, it was found that the formation of an ice jam in the downstream of bridge pier is faster than that in the upstream. The thickness distribution of the ice jam shows clearly different characteristics in front and behind of bridge piers at different stages of the ice jam.

Pounding Tuned Mass Damper (PTMD): An Innovative Damper for Subsea Pipeline and Jumper Vibration Controls

2017 ◽  
Author(s):  
Devendra Patil ◽  
Akshay Kalia ◽  
Gangbing Song ◽  
Marcus Lara
Keyword(s):  
Oil And Gas ◽  
Vibration Suppression ◽  
Tuned Mass Damper ◽  
Operational Flexibility ◽  
Subsea Pipeline ◽  
University Of Houston ◽  
Novel Device ◽  
Mass Damper ◽  
The University ◽  
The Impact

This paper discusses the pounding tuned mass damper (PTMD) — a novel device developed in a joint collaboration between OneSubsea, a Schlumberger Company and the University of Houston to absorb and dissipate the undesired vibrations generated due to VIV and FIV in subsea pipeline and jumpers. The PTMD is based on principles of both the tuned mass damper (TMD) and the impact damper. The tuned mass in the PTMD absorbs the kinetic energy of the structure and dissipates the absorbed energy through collisions on viscoelastic material. During development, detailed numerical analysis and experimentation were performed to study the effectiveness of the PTMD on the jumper. In the experiment, a full size M-shaped jumper was tested in both air and shallow water conditions for VIV at NASA’s Natural Buoyancy Laboratory (NBL). The experiment also examined the robustness of PTMD for different frequency VIVs. Experimental results showed that the PTMD effectively reduced the in-plane and out-plane vibration of the jumper up to 90%. The observed reduction in vibration amplitude can reduce fatigue damage to jumpers, thus enabling oil and gas operators to optimize spending on vibration mitigation devices, minimize lost revenues, improve system lifespan and availability, and enhance operational flexibility. Reduction in stress of these pipelines also means improved reliability and reduction in costs associated with inspection, maintenance, and repair of subsea jumpers and pipelines. These long-term financial benefits and ability to be installed on existing and new jumpers (pipelines) makes the PTMD a desired solution for vibration suppression in deep water environments.

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