Numerical study on nonlinear behavior of a collapsing bubble cloud in an ultrasound field

2006 ◽  
Vol 119 (5) ◽  
pp. 3408-3408
Author(s):  
Shin Yoshizawa ◽  
Teiichiro Ikeda ◽  
Shu Takagi ◽  
Yoichiro Matsumoto
Keyword(s):  
Numerical Study ◽  
Nonlinear Behavior ◽  
Bubble Cloud ◽  
Ultrasound Field

Numerical study using stiffness parameters on the nonlinear behavior of RCA pavements under heavy traffic loads

2021 ◽  
pp. 100582
Author(s):  
Merve Akbas ◽  
Bilal Özaslan ◽  
Hadi Khanbabazadeh ◽  
Recep İyisan
Keyword(s):  
Numerical Study ◽  
Heavy Traffic ◽  
Nonlinear Behavior ◽  
Traffic Loads

A numerical study on the nonlinear behavior of corner supported flat and curved panels

2017 ◽  
Vol 88 (4) ◽  
pp. 503-516 ◽  
Author(s):  
Gaurav Watts ◽  
M. K. Singha ◽  
S. Pradyumna
Keyword(s):  
Numerical Study ◽  
Nonlinear Behavior ◽  
Curved Panels

In-plane response of unreinforced masonry walls confined by reinforced concrete tie-columns and tie-beams

2017 ◽  
Vol 20 (11) ◽  
pp. 1632-1643 ◽  
Author(s):  
Masoud Amouzadeh Tabrizi ◽  
Masoud Soltani
Keyword(s):  
Numerical Study ◽  
Nonlinear Behavior ◽  
Numerical Approach ◽  
Masonry Wall ◽  
Masonry Walls ◽  
Lateral Loads ◽  
Confined Masonry ◽  
Smeared Crack ◽  
Modeling Strategy ◽  
Reversed Cyclic

This article focuses on the experimental and analytical investigations of masonry walls surrounded by tie-elements under in-plane loads. The experimental results of an unconfined and a confined masonry wall, tested under reversed cyclic lateral loads, are presented. For numerical study, a micro-modeling strategy, using smeared-crack-based approach, is adopted. In order to validate the numerical approach, experimental test results and data obtained from the literature are used, and through a systematic parametric study, the influence of adjoining walls and number of tie-columns on the seismic behavior of confined masonry panels is numerically assessed and a simple but rational method for predicting the nonlinear behavior of these structures is proposed.

On the nonlinear performance of a tuned sloshing damper under small amplitude excitation

2019 ◽  
Vol 25 (21-22) ◽  
pp. 2695-2705 ◽  
Author(s):  
Anuja Roy ◽  
Zili Zhang ◽  
Aparna (Dey) Ghosh ◽  
Biswajit Basu
Keyword(s):  
Small Amplitude ◽  
Numerical Study ◽  
Nonlinear Behavior ◽  
Wave Theory ◽  
Small Mass ◽  
Mass Ratio ◽  
Hybrid Testing ◽  
Low Mass ◽  
Low Mass Ratio ◽  
Nonlinear Performance

This paper explores the potential of a tuned sloshing damper (TSD) in the control of small amplitude vibrations, which is often important from serviceability considerations, through the use of a relatively small mass ratio of the damper liquid. To investigate the nonlinear behavior of the TSD, real-time hybrid testing is conducted in which a single rectangular tank containing water constitutes the prototype TSD. The structure is modeled as a multi-degree-of-freedom system. Two different base input motions, namely harmonic and synthetically generated broad-banded input, are considered. The sensitivity of the TSD performance to tuning ratio vis-à-vis low mass ratio is studied. The experimental results are compared with those obtained from a numerical study carried out using the shallow water wave theory-based nonlinear, semi-empirical model, for the simulation of the sloshing motion of the TSD liquid (water). Results indicate that in the tuned condition, even with a low mass ratio, the TSD is highly effective in the suppression of the small amplitude vibrations, which is underestimated by the simulation model.

scholarly journals STUDY ON NONLINEAR PAVEMENT RESPONSES OF LOW VOLUME ROADWAYS SUBJECT TO MULTIPLE WHEEL LOADS / NETIESINĖS KELIO DANGOS PRIKLAUSOMYBĖS NUO MAŽO INTENSYVUMO KELIŲ, VEIKIAMŲ DAUGKARTINĖMIS RATŲ APKROVOMIS, TYRIMAS

2011 ◽  
Vol 17 (1) ◽  
pp. 45-54 ◽  
Author(s):  
Minkwan Kim ◽  
Joo Hyoung Lee
Keyword(s):  
Finite Element ◽  
Numerical Study ◽  
Asphalt Pavement ◽  
Three Dimensional ◽  
Nonlinear Behavior ◽  
Element Model ◽  
Element Analysis ◽  
Nonlinear Stress ◽  
Low Volume ◽  
Stress Dependent

This paper describes numerical analyses on low volume roads (LVRs) using a nonlinear three-dimensional (3D) finite element model (FEM). Various pavement scenarios are analyzed to investigate the effects of pavement layer thicknesses, traffic loads, and material properties on pavement responses, such as surface deflection and subgrade strain. Each scenario incorporates a different combination of wheel/axle configurations and pavement geomaterial properties to analyze the nonlinear behavior of thinly surfaced asphalt pavement. In this numerical study, nonlinear stress-dependent models are employed in the base and subgrade layers to properly characterize pavement geomaterial behavior. Finite element analysis results are then described in terms of the effects of the asphalt pavement thickness, wheel/axle configurations, and geomaterial properties on critical pavement responses. Conclusions are drawn by the comparison of the nonlinear pavement responses in the base and subgrade in association with the effects of multiple wheel/axle load interactions. Santrauka Straipsnyje aprašoma skaitinė mažo intensyvumo kelių analizė, taikant netiesinį—erdvinį baigtinių elementų modelį. Skirtingi dangų paviršiaus variantai analizuojami siekiant ištirti, kokiąįtaką kelio dangos elgsenai, t. y. poslinkiams ir kelio pagrindo deformacijoms, turi dangų sluoksnių storiai, eismo apkrovos ir medžiagų savybės. Kiekvienas kelio dangos variantas turi skirtingas ratų arba ašies ir geometrinių savybių formas, kad būtų galima išanalizuoti netiesinę plonos asfalto dangos paviršiaus elgseną. Šioje skaitinėje analizėje nagrinėjami netiesiniai įtempių modeliai, kurie buvo taikomi pagrindo sluoksniams, siekiant tinkamai apibūdinti geometrinę kelio dangos elgseną. Baigtinių elementų analizės rezultatai toliau nagrinėjami atsižvelgiant į asfalto dangos storį ar ašies formą ir geometrines savybes, priklausomai nuo kritinės kelio dangos būklės. Išvados buvo gautos lyginant netiesines kelių dangos priklausomybes pagrindo sluoksnyje, atsižvelgiant į jų sąveiką su daugkartine ratų apkrova.

scholarly journals Modeling and numerical simulation of the bubble cloud dynamics in an ultrasound field for burst wave lithotripsy

2018 ◽  
Vol 144 (3) ◽  
pp. 1780-1780
Author(s):  
Kazuki Maeda ◽  
Tim Colonius ◽  
Adam D. Maxwell ◽  
Wayne Kreider ◽  
Michael R. Bailey
Keyword(s):  
Numerical Simulation ◽  
Bubble Cloud ◽  
Ultrasound Field ◽  
Cloud Dynamics

scholarly journals EVALUATION OF THE POUNDING FORCES DURING EARTHQUAKE USING EXPLICIT DYNAMIC TIME INTEGRATION METHOD

2017 ◽  
Vol 13 (3) ◽  
pp. 21-39
Author(s):  
George Bogdan Nica ◽  
Andrei Gheorghe Pricopie
Keyword(s):  
Urban Areas ◽  
Integration Method ◽  
Numerical Study ◽  
Equations Of Motion ◽  
Time Integration ◽  
Nonlinear Behavior ◽  
Implicit Time ◽  
Time Integration Method ◽  
Nonlinear Viscoelastic ◽  
Weak Structure

Abstract Pounding effects during earthquake is a subject of high significance for structural engineers performing in the urban areas. In this paper, two ways to account for structural pounding are used in a MATLAB code, namely classical stereomechanics approach and nonlinear viscoelastic impact element. The numerical study is performed on SDOF structures acted by ELCentro recording. While most of the studies available in the literature are related to Newmark implicit time integration method, in this study the equations of motion are numerical integrated using central finite difference method, an explicit method, having the main advantage that in the displacement at the ith+1 step is calculated based on the loads from the ith step. Thus, the collision is checked and the pounding forces are taken into account into the equation of motion in an easier manner than in an implicit integration method. First, a comparison is done using available data in the literature. Both linear and nonlinear behavior of the structures during earthquake is further investigated. Several layout scenarios are also investigated, in which one or more weak buildings are adjacent to a stiffer building. One of the main findings in this paper is related to the behavior of a weak structure located between two stiff structures.

scholarly journals Enhancing Seismic Capacity of Pile-Supported Wharves Using Yielding Dampers

2013 ◽  
Vol 2013 ◽  
pp. 1-13 ◽  
Author(s):  
Seyed Amin Mousavi ◽  
Khosrow Bargi
Keyword(s):  
Numerical Study ◽  
Retaining Wall ◽  
Nonlinear Behavior ◽  
Optimization Procedure ◽  
Seismic Capacity ◽  
Ground Acceleration ◽  
Design Guideline ◽  
Factors Affecting ◽  
Quay Wall ◽  
The Stability

This paper presents a numerical study on the seismic response of pile-supported wharves equipped with metallic yielding dampers. Using 20 ground acceleration records, the contribution of the yielding damper is examined, and its main parameters are optimized through a parametric study. In the current study, considering coupling effects of different parameters, a new optimization procedure is proposed. The obtained results indicate that the stability condition of the retaining wall (quay wall) behind the wharf, period of the soil-wharf system, and also maximum allowable ductility ratio of the damper are the key factors affecting the optimum damper parameters. A simplified design guideline is proposed for either the design or the retrofit purposes followed by a numerical assessment to evaluate the contribution of the proposed damper on the seismic behavior of a typical pile-supported wharf. The obtained results show that yielding dampers, through their nonlinear behavior, can dissipate a large portion of seismic input energy and mitigate piles damages which have been observed in earlier earthquake events.

scholarly journals Numerical Simulations of the Nonlinear Interaction of a Bubble Cloud and a High Intensity Focused Ultrasound Field

Acoustics ◽  
2019 ◽  
Vol 1 (4) ◽  
pp. 825-836
Author(s):  
Vanhille ◽  
Hynynen
Keyword(s):  
Nonlinear Interaction ◽  
High Intensity ◽  
Focused Ultrasound ◽  
High Intensity Focused Ultrasound ◽  
Equation Modeling ◽  
Mechanical Index ◽  
Bubble Cloud ◽  
Focal Area ◽  
Ultrasound Field ◽  
Bubble Oscillations

We studied the effects of a small bubble cloud located at the pre-focal area of a high-intensity focused ultrasound field. Our objective is to show that bubbles can modify the bioeffects of an ultrasound treatment in muscle tissue. We model a three-dimensional ultrasound field in an idealized configuration of real operating conditions. Simulations are performed using a combined method based on the Khokhlov-Zabolotskaya-Kuznetsov equation, describing the ultrasound propagation, and a Rayleigh-Plesset equation, modeling the bubble oscillations. The nonlinear interaction of the ultrasound field and the bubble oscillations is considered. Results with and without bubbles for different void fractions of the cloud and different acoustic powers are compared. The cloud induces scattering, nonlinear distortion, and shielding of ultrasound, which increase the mechanical index in the pre-focal zone, shift the location, reduce the size, and modify the shape of the volume of tissue of high mechanical index values, and lower the pressure at the intended focus considerably. Although some hypothesis and parameters used in the models do not fit the real HIFU situations, the simulation results suggest that the effects caused by a bubble cloud located in the pre-focal area should be considered and monitored to ensure the safety of high-intensity focused ultrasound treatments.

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