scholarly journals Evaluation of Induced Settlements of Piled Rafts in the Coupled Static-Dynamic Loads Using Neural Networks and Evolutionary Polynomial Regression

2017 ◽  
Vol 2017 ◽  
pp. 1-23 ◽  
Author(s):  
Ali Ghorbani ◽  
Mostafa Firouzi Niavol

Coupled Piled Raft Foundations (CPRFs) are broadly applied to share heavy loads of superstructures between piles and rafts and reduce total and differential settlements. Settlements induced by static/coupled static-dynamic loads are one of the main concerns of engineers in designing CPRFs. Evaluation of induced settlements of CPRFs has been commonly carried out using three-dimensional finite element/finite difference modeling or through expensive real-scale/prototype model tests. Since the analyses, especially in the case of coupled static-dynamic loads, are not simply conducted, this paper presents two practical methods to gain the values of settlement. First, different nonlinear finite difference models under different static and coupled static-dynamic loads are developed to calculate exerted settlements. Analyses are performed with respect to different axial loads and pile’s configurations, numbers, lengths, diameters, and spacing for both loading cases. Based on the results of well-validated three-dimensional finite difference modeling, artificial neural networks and evolutionary polynomial regressions are then applied and introduced as capable methods to accurately present both static and coupled static-dynamic settlements. Also, using a sensitivity analysis based on Cosine Amplitude Method, axial load is introduced as the most influential parameter, while the ratio l/d is reported as the least effective parameter on the settlements of CPRFs.

2012 ◽  
Vol 446-449 ◽  
pp. 837-840
Author(s):  
Yu Zhao ◽  
Shu Fang Yuan ◽  
Jian Wei Zhang

The underwater structure of power house is major structure under the dynamic loads of unit. The vibration problem is very common in operation. So the structures should have sufficient stiffness to resist dynamic loads of unit. This paper establishes three-dimensional finite element models with finite element analysis software—ANSYS. Dynamic characteristics of the power house and dynamic responses of structure under earthquake are analyzed. The results of the computation show that fluid-solid coupling may be ignored when studying dynamic characteristics of structures of the underground power house.


2008 ◽  
Vol 130 (3) ◽  
Author(s):  
Anatoly A. Kozhenkov ◽  
Rafail S. Deitch

This paper presents the modeling procedure for a high-velocity rotor system (RS) combined with sliding bearings. The equations for motion of the RS parts were derived based on the model of a rotating elastic medium. Lubrication layers have been calculated with the use of the Reynolds equations. The discretization of the RS model has been carried out using three-dimensional contact finite element method and two-dimensional method of finite differences. The integration with respect to time is performed by an absolutely stable step-by-step method. The paper also compares and discusses computed and experimental amplitude-frequency characteristics of the self-oscillating turbocharger’s RS. The values of dynamic loads in parts, as well as reactions, clearances, and losses in bearings, computed based on the presented modeling procedure make the RS designing more accurate and reliable.


2013 ◽  
Vol 438-439 ◽  
pp. 565-568
Author(s):  
Jian Hua Zhang ◽  
Zhi Chao Yang ◽  
Jin Jin Xu

In recent years, hydropower as one kind of the most economical and environmental energy got the swift and violent development, it is important to ensure the safety of hydropower station. Combined with practical engineering of Dandong hydropower station, the simulation model of hydropower station is built by three-dimensional finite element software, the bifurcated pipe is analyzed under the static and dynamic loads which are caused by reconstruction of Yueshan railway station. The results show that the stresses and displacements increment are smaller under the loads, the natural frequency of vibration and the frequency of railway bridge are different largely, which does not produce resonance. Therefore, the hydropower meets the safety requirements under different railway bridge loads.


2007 ◽  
Vol 35 (3) ◽  
pp. 226-238 ◽  
Author(s):  
K. M. Jeong ◽  
K. W. Kim ◽  
H. G. Beom ◽  
J. U. Park

Abstract The effects of variations in stiffness and geometry on the nonuniformity of tires are investigated by using the finite element analysis. In order to evaluate tire uniformity, a three-dimensional finite element model of the tire with imperfections is developed. This paper considers how imperfections, such as variations in stiffness or geometry and run-out, contribute to detrimental effects on tire nonuniformity. It is found that the radial force variation of a tire with imperfections depends strongly on the geometrical variations of the tire.


1992 ◽  
Vol 20 (1) ◽  
pp. 33-56 ◽  
Author(s):  
L. O. Faria ◽  
J. T. Oden ◽  
B. Yavari ◽  
W. W. Tworzydlo ◽  
J. M. Bass ◽  
...  

Abstract Recent advances in the development of a general three-dimensional finite element methodology for modeling large deformation steady state behavior of tire structures is presented. The new developments outlined here include the extension of the material modeling capabilities to include viscoelastic materials and a generalization of the formulation of the rolling contact problem to include special nonlinear constraints. These constraints include normal contact load, applied torque, and constant pressure-volume. Several new test problems and examples of tire analysis are presented.


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