Design optimization of triple friction pendulums for base-isolated high-rise buildings

2019 ◽  
Vol 22 (13) ◽  
pp. 2727-2740
Author(s):  
Yanqing Xu ◽  
Tong Guo ◽  
Ping Yan
Keyword(s):  
Equations Of Motion ◽  
Variable Stiffness ◽  
Service Level ◽  
Design Parameters ◽  
Base Shear ◽  
Optimization Analysis ◽  
High Rise ◽  
Significant Difference ◽  
Friction Pendulum ◽  
Stiffness And Damping

The triple friction pendulum bearing, as a novel seismic isolator, has received much attention due to its notable advantages such as variable stiffness and damping; however, existing investigations and applications are mainly for low-rise or medium-rise buildings. In order to determine optimal design parameters of triple friction pendulum bearings for high-rise buildings, equations of motion for an isolated high-rise building are derived, and an evaluation function is developed to indicate the isolation effect with different pendulum parameters. In the optimization analysis, seven ground motions are scaled to three levels (corresponding to the service level, the design basis, and the maximum considered earthquakes, respectively) and the genetic algorithm is applied to determine the optimal pendulum parameters. The optimization results are compared with those obtained by the single-degree-of-freedom model, where significant difference is observed, showing the necessity of the presented study. Using the optimal parameters of triple friction pendulum bearings, seismic responses of the isolated building are analyzed and compared with those of the building isolated using the single friction pendulum bearings and the base-fixed building, where it is observed that the triple friction pendulum bearing is more effective and reliable in reducing base shear, floor acceleration, and story drifts.

Plain and Full Floating Bearing Simulations With Rigid Shaft Dynamics

2007 ◽  
Author(s):  
Ian McLuckie ◽  
Scott Barrett
Keyword(s):  
System Development ◽  
Equations Of Motion ◽  
Time Integration ◽  
Forced Response ◽  
Design Parameters ◽  
Integration Scheme ◽  
Damping Coefficients ◽  
Time Integration Scheme ◽  
Combined Solution ◽  
Stiffness And Damping

This paper shows a promising predictive bearing model that can be used to reduce turbocharger bearing system development times. Turbocharger development is normally done by varying design parameters such as bearing geometry in a very time consuming experimentation process. Full Floating Bearings (FFB) are used in most automotive turbochargers and, due to emissions regulations, there has been a push towards downsizing engines and applying turbo charging to generate optimized engine solutions for both gasoline and diesel applications. In this paper the turbocharger rotor is regarded as being rigid, and the equations of motion are solved using the Bulirsch Stoer time integration scheme. These equations are solved simultaneously with the bearing model which is used also to determine nonlinear stiffness and damping coefficients. The bearings are solved using a Rigid Hydro Dynamic (RHD) Finite Difference Successive Over Relaxation (SOR) scheme of Reynolds equation that includes both rotational and squeeze velocity terms. However the solver can also consider bearing and rotor elasticity in a Multi-Body Dynamic (MBD) and Elasto-Hydro Dynamic (EHD) combined solution. Two bearing types have been studied, a plain grooved (PGB) and a full floating bearing (FFB) for comparative purposes. The mathematical models used are generic and suitable for whole engine bearing studies. The results in this paper show they are suitable for determining the onset of turbocharger bearing instability, and also the means by which bearing instability may be suppressed. The current study has investigated forced response with the combined effects of gravity and unbalance. It is worth noting that the effects of both housing excitation and aerodynamic excitation from the compressor and turbine can be easily accommodated, and will be the subject of a future paper. Other topics introduced here that will be explored further in the future include the effect of bearing and rotor flexibility in the MBD and EHD solution and the use of automatically generated stiffness and damping coefficients for any bearing geometry.

Behavior of Quintuple Friction Pendulum System Under Near-Fault Earthquakes

2017 ◽  
Vol 11 (05) ◽  
pp. 1750017
Author(s):  
A. H. Sodha ◽  
D. P. Soni ◽  
M. K. Desai ◽  
S. Kumar
Keyword(s):  
Adaptive Behavior ◽  
Service Level ◽  
Base Shear ◽  
Pendulum System ◽  
Directivity Effect ◽  
Sliding Surfaces ◽  
Near Fault ◽  
Effective Period ◽  
Fling Step ◽  
Friction Pendulum

The Quintuple Friction Pendulum (QTFP) system is a new generation sliding isolation having six spherical sliding surfaces with five effective pendula. Due to multiple sliding surfaces, QTFP system shows highly adaptive behavior under different hazard level of earthquakes, despite being a passive system. The paper describes mathematical model and seismic response of QTFP system under 60 earthquake records consisting of service level, design basis and maximum considered earthquakes. To study the effect of directivity focusing and fling step, additional 15 records consist of far-field, near-fault with forward directivity and fling step effect are also considered. Three types of effective period and effective damping in combination with two different displacement capacities of QTFP bearing resulting in six isolator designs are considered. The seismic demand parameters like base shear, top floor absolute acceleration and isolator displacement have been studied. It is found that the QTFP bearing stiffens at low input, softens with increasing input, and then stiffens again at higher levels of input. Thus, it shows highly adaptive behavior under different hazard levels of earthquake. Further, due to forward and backward momentum conveyed by the directivity pulse, near-fault directivity effect imposes higher demand compared to fling step containing only forward momentum.

Comparative Study of the Linear and Non-Linear Locomotive Response

1979 ◽  
Vol 101 (3) ◽  
pp. 263-271 ◽  
Author(s):  
E. H. Chang ◽  
V. K. Garg ◽  
C. H. Goodspeed ◽  
S. P. Singh
Keyword(s):  
Dynamic Response ◽  
Degrees Of Freedom ◽  
Equations Of Motion ◽  
Design Parameters ◽  
Suspension Systems ◽  
Damping Characteristics ◽  
Time Histories ◽  
Steady State Responses ◽  
Stiffness And Damping ◽  
State Responses

A mathematical model for a six-axle locomotive is developed to investigate its dynamic response on tangent track due to vertical and/or lateral track irregularities. The model represents the locomotive as a system of thirty-nine degrees of freedom. The nonlinearities considered in the model are primarily associated with stiffness and damping characteristics of the primary suspension system. The transient and steady-state responses of the locomotive are obtained for the linear and nonlinear primary suspension systems. The response time-histories of the locomotive obtained by integrating the generalized equations of motion are presented. The potential uses of the model are indicated for studying the influence of different design parameters and predicting subsequent dynamic response.

Effect of Bay Spacing on Design Parameters of RC Structures Subjected to Lateral Loads

2021 ◽  
Vol 7 (3) ◽  
Author(s):  
A. Vimala ◽  
A. Vimala
Keyword(s):  
Structural Model ◽  
Design Parameters ◽  
Frame Structures ◽  
Optimal Size ◽  
Lateral Loads ◽  
Base Shear ◽  
Structural Configuration ◽  
Rc Structures ◽  
High Rise ◽  
Computer Based

Structural configuration is one of the important parameters to control the performance of multi-storeyed structures subjected to lateral loads. On other hand, also the economy of multi-storeyed structures depends on the spacing of columns. The present investigation is aiming to find the effect of bay spacing on the performance of medium to high rise RC structures subjected to lateral loads. In this regard, a computer- based analysis is carried out for 10, 15, 20, 25 and 30 storied bare frame structures. Each structure performance under lateral loads is investigated for 4 types of bay spacing i.e. 5m, 6m, 7.2m and 8.64m, with an increment of 20% bay space each time. For each structural model, the behaviour of the structure is examined in terms of storey displacement, storey drift and base shear. The quantitative parametric comparison is done between all the models mentioned and has identified the optimal size of the bay spacing to suit the aspect ratio of the structure is proposed.

Effects of Base Isolation on Multi-Layer and High-Level Framework

2011 ◽  
Vol 255-260 ◽  
pp. 2568-2572
Author(s):  
Hai Qing Liu ◽  
Xiao Guo ◽  
Hao Wang
Keyword(s):  
Seismic Waves ◽  
Base Isolation ◽  
Equations Of Motion ◽  
Time History ◽  
Structural System ◽  
Base Shear ◽  
High Rise ◽  
Isolated Structures ◽  
Rubber Bearings ◽  
High Level

This paper expounded the basic principle of the base-isolated structures. Established the equations of motion of single particle and multi-particle base isolation structural system. Adopted multi-layer and high-level framework groups, added laminated rubber bearings in the bottom respectively, input EL Centro seismic waves, and then the modal, time-history, base shear are compared and analyzed. By comparing the results obtained: base-isolated structure used in high-rise building can decrease a certain degree of the seismic response, in the multi-layer building the effect was more apparent. It also confirmed that the application of base isolation on multi-layer and high-level framework in the existing conditions still had some limitations.

scholarly journals A Variable Parameter Ambient Vibration Control Method Based on Quasi-Zero Stiffness in Robotic Drilling Systems

Machines ◽  
2021 ◽  
Vol 9 (3) ◽  
pp. 67
Author(s):  
Laixi Zhang ◽  
Chenming Zhao ◽  
Feng Qian ◽  
Jaspreet Singh Dhupia ◽  
Mingliang Wu
Keyword(s):  
Vibration Control ◽  
Vibration Isolation ◽  
Control Method ◽  
Control Strategies ◽  
Equations Of Motion ◽  
Variable Parameter ◽  
Harmonic Balance Method ◽  
Variable Stiffness ◽  
Ambient Vibration ◽  
Robotic Drilling

Vibrations in the aircraft assembly building will affect the precision of the robotic drilling system. A variable stiffness and damping semiactive vibration control mechanism with quasi-zero stiffness characteristics is developed. The quasi-zero stiffness of the mechanism is realized by the parallel connection of four vertically arranged bearing springs and two symmetrical horizontally arranged negative stiffness elements. Firstly, the quasi-zero stiffness parameters of the mechanism at the static equilibrium position are obtained through analysis. Secondly, the harmonic balance method is used to deal with the differential equations of motion. The effects of every parameter on the displacement transmissibility are analyzed, and the variable parameter control strategies are proposed. Finally, the system responses of the passive and semiactive vibration isolation mechanisms to the segmental variable frequency excitations are compared through virtual prototype experiments. The results show that the frequency range of vibration isolation is widened, and the stability of the vibration control system is effectively improved without resonance through the semiactive vibration control method. It is of innovative significance for ambient vibration control in robotic drilling systems.

scholarly journals Numerical Modelling of Reinforced Concrete Slender Walls Subjected to Coupled Axial Tension–Flexure

2021 ◽  
Vol 15 (1) ◽  
Author(s):  
Xiaowei Cheng ◽  
Haoyou Zhang
Keyword(s):  
Reinforced Concrete ◽  
Plastic Hinge ◽  
Element Model ◽  
Lateral Loading ◽  
Design Parameters ◽  
Seismic Behaviour ◽  
High Rise ◽  
Ultimate Deformation ◽  
Axial Tension ◽  
Plastic Hinge Length

AbstractUnder strong earthquakes, reinforced concrete (RC) walls in high-rise buildings, particularly in wall piers that form part of a coupled or core wall system, may experience coupled axial tension–flexure loading. In this study, a detailed finite element model was developed in VecTor2 to provide an effective tool for the further investigation of the seismic behaviour of RC walls subjected to axial tension and cyclic lateral loading. The model was verified using experimental data from recent RC wall tests under axial tension and cyclic lateral loading, and results showed that the model can accurately capture the overall response of RC walls. Additional analyses were conducted using the developed model to investigate the effect of key design parameters on the peak strength, ultimate deformation capacity and plastic hinge length of RC walls under axial tension and cyclic lateral loading. On the basis of the analysis results, useful information were provided when designing or assessing the seismic behaviour of RC slender walls under coupled axial tension–flexure loading.

scholarly journals Development of a novel variable stiffness and damping magnetorheological fluid damper

2015 ◽  
Vol 24 (8) ◽  
pp. 085021 ◽  
Author(s):  
Shuaishuai Sun ◽  
Jian Yang ◽  
Weihua Li ◽  
Huaxia Deng ◽  
Haiping Du ◽  
...  
Keyword(s):  
Variable Stiffness ◽  
Magnetorheological Fluid ◽  
Magnetorheological Fluid Damper ◽  
Fluid Damper ◽  
Stiffness And Damping

Research on the Optimal Design Method of the Main Components for the Wheelchair Pickup

2013 ◽  
Vol 791-793 ◽  
pp. 799-802
Author(s):  
Ya Ping Wang ◽  
H.R. Shi ◽  
L. Gao ◽  
Z. Wang ◽  
X.Y. Jia ◽  
...  
Keyword(s):  
Parametric Design ◽  
Design Method ◽  
Basic Function ◽  
Design Parameters ◽  
Algorithm Optimization ◽  
Optimization Analysis ◽  
Research Designs ◽  
Optimal Design Method ◽  
Main Components

With the increasing of the aging of population all over the world, and With the inconvenience coming from diseases and damage, there will be more and more people using the wheelchair as a tool for transport. When it cant be short of the wheelchair in the daily life, the addition of the function will bring the elevation of the quality of life for the unfortunate. Staring with this purpose, the research designs a pickup with planetary bevel gear for the wheelchair. After determining the basic function of the wheelchair aids, the study determines the design parameters by using the knowledge of parametric design and completes the model for the system with Pro/E, on the other hand, it completes key components optimization analysis which is based on genetic algorithm optimization.

scholarly journals Impact of Cross-Tie Properties on the Modal Behavior of Cable Networks on Cable-Stayed Bridges

2015 ◽  
Vol 2015 ◽  
pp. 1-14 ◽  
Author(s):  
Javaid Ahmad ◽  
Shaohong Cheng ◽  
Faouzi Ghrib
Keyword(s):  
Analytical Model ◽  
Design Parameters ◽  
Reference Base ◽  
Cable Network ◽  
Cable Networks ◽  
Modal Behavior ◽  
Stiffness And Damping ◽  
Main Cables ◽  
The Impact ◽  
Selection Of

Dynamic behaviour of cable networks is highly dependent on the installation location, stiffness, and damping of cross-ties. Thus, these are the important design parameters for a cable network. While the effects of the former two on the network response have been investigated to some extent in the past, the impact of cross-tie damping has rarely been addressed. To comprehend our knowledge of mechanics associated with cable networks, in the current study, an analytical model of a cable network will be proposed by taking into account both cross-tie stiffness and damping. In addition, the damping property of main cables in the network will also be considered in the formulation. This would allow exploring not only the effectiveness of a cross-tie design on enhancing the in-plane stiffness of a constituted cable network, but also its energy dissipation capacity. The proposed analytical model will be applied to networks with different configurations. The influence of cross-tie stiffness and damping on the modal response of various types of networks will be investigated by using the corresponding undamped rigid cross-tie network as a reference base. Results will provide valuable information on the selection of cross-tie properties to achieve more effective cable vibration control.

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