scholarly journals High-performance practical stiffness analysis of high-rise buildings using superfloor elements

2020 ◽  
Vol 7 (2) ◽  
pp. 211-227
Author(s):  
Ahmed A Torky ◽  
Youssef F Rashed
Keyword(s):  
Boundary Element Method ◽  
Boundary Element ◽  
Stiffness Matrix ◽  
High Performance ◽  
Parallel Processors ◽  
Element Formulation ◽  
Processing Unit ◽  
Stiffness Analysis ◽  
Industrial Level ◽  
Element Method

Abstract This study develops a high-performance computing method using OpenACC (Open Accelerator) for the stiffness matrix and load vector generation of shear-deformable plates in bending using the boundary element method on parallel processors. The boundary element formulation for plates in bending is used to derive fully populated displacement-based stiffness matrices and load vectors at degrees of freedom of interest. The computed stiffness matrix of the plate is defined as a single superfloor element and can be solved using stiffness analysis, $Ku = F$, instead of the conventional boundary element method, $Hu = Gt$. Fortran OpenACC code implementations are proposed for the computation of the superfloor element’s stiffness, which includes one serial computing code for the CPU (central processing unit) and two parallel computing codes for the GPU (graphics processing unit) and multicore CPU. As industrial level practical floors are full of supports and geometrical information, the computation time of superfloor elements is reduced dramatically when computing on parallel processors. It is demonstrated that the OpenACC implementation does not affect numerical accuracy. The feasibility and accuracy are confirmed by numerical examples that include real buildings with industrial level structural floors. Engineering computations for massive floors with immense geometrical detail and a multitude of load cases can be modeled as is without the need for simplification.

Reduced-Order Modeling of Unsteady Flows About Complex Configurations Using the Boundary Element Method

2002 ◽  
Vol 124 (4) ◽  
pp. 988-993 ◽  
Author(s):  
V. Esfahanian ◽  
M. Behbahani-nejad
Keyword(s):  
Boundary Element Method ◽  
Boundary Element ◽  
Three Dimensional ◽  
Unsteady Flows ◽  
Reduced Order Modeling ◽  
Element Formulation ◽  
Reduced Order Models ◽  
Reduced Order ◽  
Naca 0012 ◽  
Element Method

An approach to developing a general technique for constructing reduced-order models of unsteady flows about three-dimensional complex geometries is presented. The boundary element method along with the potential flow is used to analyze unsteady flows over two-dimensional airfoils, three-dimensional wings, and wing-body configurations. Eigenanalysis of unsteady flows over a NACA 0012 airfoil, a three-dimensional wing with the NACA 0012 section and a wing-body configuration is performed in time domain based on the unsteady boundary element formulation. Reduced-order models are constructed with and without the static correction. The numerical results demonstrate the accuracy and efficiency of the present method in reduced-order modeling of unsteady flows over complex configurations.

The Dual-Reciprocity Boundary Element Method Solution for Gas Recovery from Unconventional Reservoirs with Discrete Fracture Networks

SPE Journal ◽  
2020 ◽  
Vol 25 (06) ◽  
pp. 2898-2914
Author(s):  
Miao Zhang ◽  
Luis F. Ayala
Keyword(s):  
Boundary Element Method ◽  
Boundary Element ◽  
Nonlinear Partial Differential Equations ◽  
Boundary Integral ◽  
Element Formulation ◽  
Gas Reservoirs ◽  
Gas Recovery ◽  
Infinite Conductivity ◽  
Fractured Horizontal Wells ◽  
Element Method

Summary In this paper, we present a novel application of the dual-reciprocity boundary-element formulation (DRBEM) to model compressible (gas) fluid flow in tight and shale-gas reservoirs containing arbitrary distributed finite- or infinite-conductivity discrete fractures. Compared with the standard boundary-element method (BEM), the DRBEM transforms the nonlinear domain integrals at the righthand side (RHS) of BEM formulations for nonlinear partial differential equations into equivalent boundary integrals. This transformation allows retention of the domain-integral-free, boundary-integral-only character of standard BEM approaches. The proposed approach is based on coupling DRBEM with the finite-volume method (FVM) in which a multidimensional system is solved by integrating over a line with random fractures. The resulting system of equations is solved simultaneously for fracture and matrix boundary conditions by combining DRBEM and FVM without invoking any approximation for pressure-dependent nonlinear terms such as gas viscosity and compressibility. Numerical examples and field cases are presented to test the validity and showcase the capabilities of the proposed approach. The proposed model provides a general framework that can be applied to a variety of well and fracture geometries and operating schedules, and it is used to analyze production behavior for these complex systems. To the best of the authors’ knowledge, this is the first successful application of the dual-reciprocity principle to the BEM analysis of massively fractured horizontal wells (MFHWs) performance in natural-gas formations in which nonlinear, pressure-dependent gas properties are captured without approximation.

AN INNOVATIVE BOUNDARY ELEMENT FORMULATION FOR BUILDING SLABS

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Ahmed U. Abdelhady ◽  
Youssef F. Rashed
Keyword(s):  
Boundary Element ◽  
Stiffness Matrix ◽  
Degrees Of Freedom ◽  
Research Work ◽  
Element Formulation ◽  
Supporting Cells ◽  
Stiffness Analysis ◽  
Stiffness Matrices ◽  
Limited Applicability ◽  
Generalized Displacements

Slab supported by beams (i.e. beam-slab floor) is a common practice in the construction of buildings. Modeling this slab type using the boundary element method (BEM) is an essential step to provide seamless frameworks for the analysis of buildings with complex geometries. However, one of the most challenging difficulties that have been facing research efforts in this area is its theoretical setting with limited applicability to practical building slabs. This limitation is addressed in this research work and a practical BEM-based formulation for the slab-beam floor is presented. The presented formulation discretizes the connection area between the slab, and beams and columns into cells (supporting cells). The centroids of these cells are used to carry out an additional collocation scheme which is required to solve the resulting system of equations. To generate the slab stiffness matrix, the generalized displacements that correspond to the supporting cells’ degrees of freedom are set to unity (one at a time). By assembling the generated slab stiffness matrix with beams and columns stiffness matrices using the stiffness analysis method, the overall stiffness matrix is obtained. Hooke’s law is then applied to calculate the generalized displacements and straining actions are obtained in the post-processing phase. The developed formulation is applied to an example to validate its results by comparing it with the analytical solution.

WAVELET NATURAL BOUNDARY ELEMENT METHOD FOR THE NEUMANN EXTERIOR PROBLEM OF STOKES EQUATIONS

2006 ◽  
Vol 04 (01) ◽  
pp. 23-39 ◽  
Author(s):  
WEN-SHENG CHEN ◽  
XINGE YOU ◽  
BIN FANG ◽  
YUANYAN TANG ◽  
JIAN HUANG
Keyword(s):  
Boundary Element Method ◽  
Boundary Element ◽  
Stiffness Matrix ◽  
Stokes Equations ◽  
Exterior Problem ◽  
Natural Boundary ◽  
Node Number ◽  
Element Approach ◽  
Natural Boundary Element Method ◽  
Element Method

Natural boundary element approach is a promising method to solve boundary value problems of partial differential equations. This paper addresses the Neumann exterior problem of Stokes equations using the wavelet natural boundary element method. The Stokes exterior problem is reduced into an equivalent Hadamard-singular Natural Integral Equation (NIE). By virtue of the wavelet-Galerkin algorithm, the simple and accurate computational formulae of stiffness matrix are obtained. The 2J+3 × 2J+3 stiffness matrix is sparse and determined only by its 2J + 3J + 1 entries. It greatly decreases the computational complexity. Also, the condition number of stiffness matrix is [Formula: see text], where N is the discrete node number. This indicates that the proposed algorithm is more stable than that of classical finite element method. The error estimates are established for the wavelet-Galerkin approximate solution. Several numerical examples are given to evaluate the performance of our method with encouraging results.

scholarly journals High-Precision Guide Stiffness Analysis Method for Micromechanism Based on the Boundary Element Method

2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Manzhi Yang ◽  
Zhenyang Lv ◽  
Gang Jing ◽  
Wei Guo ◽  
Yumei Huang ◽  
...  
Keyword(s):  
Boundary Element Method ◽  
Boundary Element ◽  
High Precision ◽  
Complex Structures ◽  
Analysis Method ◽  
Guide Rail ◽  
Stiffness Analysis ◽  
Guiding Principle ◽  
Parasitic Motion ◽  
Element Method

The guide stiffness performance directly affects the motion of the micromechanism in accuracy and security. Therefore, it is crucial to analyze the guide stiffness precisely. In this paper, a high-precision guide stiffness analysis method for the micromechanism by the boundary element method (BEM) is proposed. The validity and accuracy of the analysis method are tested by a guide stiffness experiment. In order to ensure the accuracy and safety during the micromechanism motion, a guiding unit of the micromechanism was designed based on the guiding principle. The guiding unit can provide parasitic motion and additional force in the motion of the micromechanism. Then, the stiffness equations of the beam element are derived by the boundary element method. The stiffness equation of straight circular flexure hinge is analyzed by rigid discretization and rigid combination, and the guide stiffness of the mechanism is investigated by rigid combination. Finally, according to the actual situation, the stiffness matrix of the guide rail (Kb) was proposed, and the analytical value of the guide stiffness was calculated to be 22.2 N/μm. The guide stiffness performance experiment was completed, and the experimental value is 22.3 N/μm. Therefore, the error between the analysis method and the experimental results is 0.45%. This study provides a new method for the stiffness analysis of high-precision micromechanisms and presents a reference for the design and stiffness analysis of complex structures. This method is helpful for stiffness analysis of the microrotary mechanism with high accuracy.

Application of the Boundary Element Method to Predict the Acoustic Field in a Two-Dimensional Duct

1991 ◽  
Author(s):  
Carl S. Pates ◽  
Uday S. Shirahatti
Keyword(s):  
Boundary Element Method ◽  
Boundary Element ◽  
Accurate Method ◽  
Classical Solutions ◽  
Element Formulation ◽  
Two Dimensional ◽  
Mean Flow ◽  
Flight Vehicles ◽  
Acoustic Problem ◽  
Element Method

Abstract In the development of the newer supersonic and hypersonic flight vehicles, an increased need for the analysis of acoustic fields and the response of structures to acoustic loads in the presence of high temperature and large mean flow velocities have become necessary. A major concern has been in the area of pressure fields associated with ducts. Such acoustic ducts are frequently used to test the response of various structural elements of flight vehicles. Many new methods have been created and used to approximate the sound fields in ducts. Since the region or boundary of an acoustic problem can extend to infinity, some approximating methods require much time and effort to solve the problem. Many ways have been examined to simplify the acoustic problem and still obtain reasonable results. In the past thirty years, the boundary element method (BEM) has been researched and proven to be an extremely simplified and accurate method for solving acoustic problems. Since BEM only discretizes the boundary, the dimensionality of the problem is reduced by one. This paper presents a boundary element formulation to predict the pressure field in a two-dimensional acoustic duct. The boundary conditions basically consist of two types: known pressure or known normal derivative of pressure. In order to examine the boundary element method, a 2-D rectangular duct problem will be investigated. The example problem will consist of a duct with rigid walls and a specified pressure distribution at the entrance. Pressure values will be calculated for boundary nodes using the boundary element method. These values will be compared with the available classical solutions.

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