Simplified Added-Mass Model for Evaluating the Response of Rectangular Hollow Bridge Piers under Earthquakes

2021 ◽  
Vol 26 (10) ◽  
pp. 04021076
Author(s):  
Fayun Liang ◽  
Xuan Liang ◽  
Chen Wang
Keyword(s):  
Added Mass ◽  
Bridge Piers ◽  
Mass Model

scholarly journals Added-Mass Based Efficient Fluid–Structure Interaction Model for Dynamics of Axially Moving Panels with Thermal Expansion

2020 ◽  
Vol 25 (1) ◽  
pp. 9
Author(s):  
Nikolay Banichuk ◽  
Svetlana Ivanova ◽  
Evgeny Makeev ◽  
Juha Jeronen ◽  
Tero Tuovinen
Keyword(s):  
Differential Equation ◽  
Partial Differential Equation ◽  
Galerkin Method ◽  
Fluid Structure Interaction ◽  
Weak Form ◽  
Added Mass ◽  
Mass Model ◽  
Partial Differential ◽  
Fluid Structure ◽  
Structure Interaction

The paper considers the analysis of a traveling panel, submerged in axially flowing fluid. In order to accurately model the dynamics and stability of a lightweight moving material, the interaction between the material and the surrounding air must be taken into account. The lightweight material leads to the inertial contribution of the surrounding air to the acceleration of the panel becoming significant. This formulation is novel and the case complements our previous studies on the field. The approach described in this paper allows for an efficient semi-analytical solution, where the reaction pressure of the fluid flow is analytically represented by an added-mass model in terms of the panel displacement. Then, the panel displacement, accounting also for the fluid–structure interaction, is analyzed with the help of the weak form of the governing partial differential equation, using a Galerkin method. In the first part of this paper, we represent the traveling panel by a single partial differential equation in weak form, using an added-mass approximation of the exact fluid reaction. In the second part, we apply a Galerkin method for dynamic stability analysis of the panel, and present an analytical investigation of static stability loss (divergence, buckling) based on the added-mass model.

scholarly journals Investigating the Influence of the Added Mass Effect to Marine Hydrokinetic Horizontal-Axis Turbines Using a General Dynamic Wake Wind Turbine Code

2012 ◽  
Vol 46 (4) ◽  
pp. 71-78 ◽  
Author(s):  
David C. Maniaci ◽  
Ye Li
Keyword(s):  
Wind Turbine ◽  
Unsteady Aerodynamics ◽  
Mass Effect ◽  
Added Mass ◽  
Horizontal Axis ◽  
Mass Model ◽  
Horizontal Axis Wind Turbine ◽  
Flow Acceleration ◽  
Hydrokinetic Turbines ◽  
Marine Hydrokinetic

AbstractThis paper describes a recent study to investigate the applicability of a horizontal-axis wind turbine structural dynamics and unsteady aerodynamics analysis program (FAST and AeroDyn, respectively) for modeling the forces on marine hydrokinetic turbines. This paper summarizes the added mass model that has been added to AeroDyn. The added mass model only includes flow acceleration perpendicular to the rotor disc and ignores added mass forces caused by blade deflection. A model of the National Renewable Energy Laboratory’s Unsteady Aerodynamics Experiment Phase VI wind turbine was analyzed using FAST and AeroDyn with seawater conditions and the new added mass model. The results of this analysis exhibited a 3.6% change in thrust for a rapid pitch case and a slight change in amplitude and phase of thrust for a case with 30° of yaw.

scholarly journals On estimating the reduction factor of bridge piers

2020 ◽  
Vol 157 ◽  
pp. 06012
Author(s):  
Andrei Benin ◽  
Olga Nesterova ◽  
Alexander Uzdin ◽  
Sergei Prokopovich ◽  
Yuri Rutman ◽  
...  
Keyword(s):  
Spectral Composition ◽  
Time History ◽  
Reduction Factor ◽  
Bridge Piers ◽  
Elastic Displacement ◽  
Mass Model ◽  
The Moment ◽  
Limit Position ◽  
Force Displacement ◽  
Displacement Diagram

Estimating the reduction factor for calculating massive reinforced concrete bridge piers was made. For this purpose a quasi-static “force-displacement” diagram was built up using the ANSYS software. This diagram has the form of a bilinear one, and the character of the bilinearity depends on the diameter of the reinforcing bars insignificantly. The percentage of reinforcement affects only the moment when all reinforcement bars begin to flow. The reinforcement flow takes place in the displacement interval from 3 to 5 cm. The collapse will occur when the reaction of the bearing part goes beyond the pier cross-section at pier displacements from 5 to 20 cm. Using “force-displacement” diagram, the behavior of the single-mass model with a bilinear deformation diagram and the limit displacement of 20 cm was analyzed. Then, it became possible to obtain for each accelerogram the limit elastic displacement and the limit position of the point corresponding to the maximum structure displacement during structure oscillations. It was done using real accelerograms of earthquakes with intensity 9 on the MSK scale without normalizing their amplitudes. In this case, long-period accelerograms had smaller peak accelerations, but resulted in greater plastic deformations. As a result, no evident dependence of plastic deformation on the input spectral composition was found and the value of reduction factor K1 turned out to be 0.25-0.27. However, it is shown that this reduction factor cannot be used to make transition from seismic loads obtained on the basis of time-history analysis by accelerograms to design loads.

Development of a New Added Mass Model and Dynamic Analysis for Cylindrical Tank

2006 ◽  
Author(s):  
Z. Zhuang ◽  
H. Z. Liu ◽  
Q. Li ◽  
S. Yamaguchi ◽  
M. Toyoda
Keyword(s):  
Mass Formula ◽  
Seismic Loading ◽  
Element Model ◽  
Rigid Wall ◽  
Added Mass ◽  
Mass Model ◽  
External Work ◽  
Tank Model ◽  
Key Factor ◽  
Dynamic Nonlinear Analysis

In order to investigate dynamic response under seismic loading for liquid tank, a new added mass formula and finite element model has been developed in this paper, which is implemented into ABAQUS as the user element subroutine. The simulation results for elastic-plastic Elephant Foot Bulging (EFB) and Diamond Shape Bulging (DSB) are validated the reliability for the added mass formula. Some shortcoming has been appointed out for the classical added mass equation, which is only suited for the liquid tank with rigid wall. Used the new added mass model, the dynamic nonlinear analysis for the tank has been carried out under dynamic loading. Through the response history and frequency analysis, it indicates that the external work on the tank model by earthquake loading is a key factor to result in plastic deformation of EFB and DSB.

Dynamic Interaction between Reservoir and a High Concrete Face Rockfill Dam on Deep Alluvium Deposit

2013 ◽  
Vol 353-356 ◽  
pp. 833-836
Author(s):  
Wei Jun Cen ◽  
Hui Sun ◽  
Kun Xiong
Keyword(s):  
Porous Medium ◽  
Dynamic Response ◽  
Fluid Model ◽  
Added Mass ◽  
Dynamic Interaction ◽  
Mass Model ◽  
Dam Foundation ◽  
Rockfill Dam ◽  
Concrete Face ◽  
Concrete Face Rockfill Dam

Potential-based fluid model and Westergaard added mass model were used to reflect the dynamic interaction of reservoir-CFRD(concrete face rockfill dam)-foundation coupling system. The deep alluvium deposit was treated as porous medium using Biot's dynamic consolidation theory. In the coupled analysis, the paper focused on hydrodynamic pressures in the reservoir zone, dynamic response and pore water pressure in the structure zone. The result shows that the dynamic response of added mass model is greater than that of potential-based fluid model. The porous medium of alluvium deposit is of great significance in performing soil liquefaction analysis and reservoir-dam-foundation system.

Study of the dynamics of ТПА 350 automatic mill working stand elements

2020 ◽  
Vol 76 (8) ◽  
pp. 830-840
Author(s):  
S. R. Rakhmanov ◽  
V. V. Povorotnii
Keyword(s):  
Mechanical System ◽  
Dynamic Model ◽  
Maximum Amplitude ◽  
Calculation Scheme ◽  
Dynamic Loads ◽  
Forced Oscillations ◽  
Mass Model ◽  
Automatic Mill ◽  
Hollow Billet ◽  
Oscillation Movement

To form a necessary geometry of a hollow billet to be rolled at a pipe rolling line, stable dynamics of the base equipment of the automatic mill working stand has a practical meaning. Among the forces, acting on its parts and elements, significant by value short-time dynamic loads are the least studied phenomena. These dynamic loads arise during transient interaction of the hollow billet, rollers, mandrel and other mill parts at the forced grip of the hollow billet. Basing of the calculation scheme and dynamic model of the mechanical system of the ТПА 350 automatic mill working stand was accomplished. A mathematical model of dynamics of the system “hollow billet (pipe) – working stand” within accepted calculation scheme and dynamic model of the mechanical system elaborated. Influence of technological load of the rolled hollow billet variation in time was accounted, as well as variation of the mechanical system mass, and rigidity of the ТПА 350 automatic mill working stand. Differential equations of oscillation movement for four-mass model of forked sub-systems of the automatic mill working stand were made up, results of their digital calculation quoted. Dynamic displacement of the stand elements in the inter-roller gap obtained, which enabled to estimate the results of amplitude and frequency characteristics of the branches of the mill rollers setting. It was defined by calculation, that the maximum amplitude of the forced oscillations of elements of the ТПА 350 automatic mill working stand within the inter-roller gap does not exceed 2 mm. It is much higher than the accepted value of adjusting parameters of the deformation center of the ТПА 350 automatic mill. A scheme of comprehensive modernization of the rollers setting in the ТПА 350 automatic mill working stand was proposed. It was shown, that increase of rigidity of rollers setting in the ТПА 350 automatic mill working stand enables to stabilize the amplitude of forced oscillations of the working stand elements within the inter-rollers gap and considerably decrease the induced nonuniform hollow billet wall thickness and increase quality of the rolled pipes at ТПА 350.

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