New Fast Convolution Algorithm in Boundary-Element Methods for Two- and Three-Dimensional Linear Soil Consolidation Analysis

2007 ◽  
Vol 7 (3) ◽  
pp. 236-249 ◽  
Author(s):  
F. Ma ◽  
J. Chatterjee ◽  
P. K. Banerjee
Keyword(s):  
Boundary Element ◽  
Three Dimensional ◽  
Boundary Element Methods ◽  
Soil Consolidation ◽  
Fast Convolution ◽  
Convolution Algorithm ◽  
Consolidation Analysis

Efficient Computations of Fully-Nonlinear Wave Interactions With Floating Structures

2010 ◽  
Author(s):  
Hongmei Yan ◽  
Yuming Liu
Keyword(s):  
Boundary Element ◽  
High Efficiency ◽  
Three Dimensional ◽  
Nonlinear Effects ◽  
Computational Effort ◽  
Boundary Element Methods ◽  
Computational Method ◽  
Wave Interactions ◽  
Time Step ◽  
Fully Nonlinear

We consider the problem of fully nonlinear three-dimensional wave interactions with floating bodies with or without a forward speed. A highly efficient time-domain computational method is developed in the context of potential flow formulation using the pre-corrected Fast Fourier Transform (PFFT) algorithm based on a high-order boundary element method. The method reduces the computational effort in solving the boundary-value problem at each time step to O(NlnN) from O(N2∼3) of the classical boundary element methods, where N is the total number of unknowns. The high efficiency of this method allows accurate computations of fully-nonlinear hydrodynamic loads, wave runups, and motions of surface vessels and marine structures in rough seas. We apply this method to study the hydrodynamics of floating objects with a focus on the understanding of fully nonlinear effects in the presence of extreme waves and large-amplitude body motions.

Modelling ground vibration from railways using wavenumber finite- and boundary-element methods

2005 ◽  
Vol 461 (2059) ◽  
pp. 2043-2070 ◽  
Author(s):  
X Sheng ◽  
C.J.C Jones ◽  
D.J Thompson
Keyword(s):  
Boundary Element ◽  
Singular Integrals ◽  
Moving Load ◽  
Three Dimensional ◽  
Ground Surface ◽  
Ground Vibration ◽  
Element Model ◽  
Boundary Element Methods ◽  
Element Discretization ◽  
Environmental Vibration

A mathematical model is presented for ground vibration induced by trains, which uses wavenumber finite- and boundary-element methods. The track, tunnel and ground are assumed homogeneous and infinitely long in the track direction ( x -direction). The models are formulated in terms of the wavenumber in the x -direction and discretization in the yz -plane. The effect of load motion in the x -direction is included. Compared with a conventional, three-dimensional finite- or boundary-element model, this is computationally faster and requires far less memory, even though calculations must be performed for a series of discrete wavenumbers. Thus it becomes practicable to carry out investigative study of train-induced ground vibration. The boundary-element implementation uses a variable transformation to solve the well-known problem of strongly singular integrals in the formulation. A ‘boundary truncation element’ greatly improves accuracy where the infinite surface of the ground is truncated in the boundary-element discretization. Predictions of vibration response on the ground surface due to a unit force applied at the track are performed for two railway tunnels. The results show a substantial difference in the environmental vibration that could be expected from the alternative designs. The effect of a moving load is demonstrated in a surface vibration example in which vibration propagates from an embankment into layered ground.

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