Analysis of thin walled structures using the boundary element method

1992 ◽  
Vol 9 (4) ◽  
pp. 359-363 ◽  
Author(s):  
L. Palermo ◽  
M. Rachid ◽  
W.S. Venturini
Keyword(s):  
Boundary Element Method ◽  
Boundary Element ◽  
Thin Walled Structures ◽  
Thin Walled ◽  
Element Method

scholarly journals DEVELOPMENT OF ALGORITHMS AND SOFTWARE COMPONENTS OF QUASI-STATIONARY MAGNETIC FIELDS MODELING

2018 ◽  
pp. 114-120
Author(s):  
V. Ryabenkiy ◽  
I. Chudaykin ◽  
J. Targunakova
Keyword(s):  
Boundary Element Method ◽  
Magnetic Fields ◽  
Boundary Element ◽  
Direct Problem ◽  
Numerical Verification ◽  
Software Components ◽  
Anomalous Field ◽  
Thin Walled Structures ◽  
Thin Walled ◽  
Element Method

The magnetometric section of the marine areas geophysics is characterized by the transition to a qualitatively new level of research, pipeline tracing, search for sunken ships, aerial bombs and unexploded ordnance, study of sunken objects of cultural heritage, identification of such sunken objects (inverse magnetometry problem), etc. The identification of such objects is called the inverse problem of marine magnetometry, and it belongs to the class of incorrectly posed task. The first step in solving this task is to find solution of the direct problem. A direct problem is to determine the anomalous field created by objects of a certain shape, density under certain conditions of immersion and accumulation of information about these objects. Problems of determining the anomalous field of a thin-walled objects are of particular interest. The solution to this problem is largely determined by the existence of an effective system of programs for solving three-dimensional direct magnetometry problems – finding the fields of typical objects (by using sets of such objects you can approximate real objects). The article describes the operation of the main algorithm and subroutines that are part of the main algorithm of the developed MBEM software for modeling the magnetic fields of thin-walled structures. MBEM is based on the developed modified boundary element method, based on the classical boundary element method and the secondary source method. Numerical verification has been carried out and the efficiency of the developed algorithms and software components has been established on the problems of calculating the magnetic field of thin-walled structures for which solutions are known. The example of the software complex work is given – the calculation of the resulting field of a thin-walled pipe, namely the simulation of the tension vector in the plane that is under the object at a distance of one half meter.

Stress and Strain Definition of an Open Profile Thin-Walled Beam at Constrained Torsion by Boundary Element Method

2012 ◽  
Vol 42 (2) ◽  
pp. 43-54
Author(s):  
Zlatko Zlatanov
Keyword(s):  
Boundary Element Method ◽  
Boundary Element ◽  
Stress And Strain ◽  
One Dimensional ◽  
Open Profile ◽  
Linear Algebraic Equations ◽  
Thin Walled ◽  
Definition Of ◽  
Constrained Torsion ◽  
Element Method

Stress and Strain Definition of an Open Profile Thin-Walled Beam at Constrained Torsion by Boundary Element Method Thin-walled beams with open profile at constrained torsion are investigated in this paper. A thin-walled beam loaded by an external bi-moment at constrained torsion is investigated in this paper. An analytical variant of the boundary element method (BEM) is presented, which is based on a new scheme of the integral ratios transformation of the initial parameters method in a system of linear algebraic equations. Only one dimensional integrals are used defining the one dimensional continuum.

Bend Flexibility Factors of Piping Elbows and Piping Elbows With Trunnion Attachments Using the Boundary Element Method

2009 ◽  
Author(s):  
Manuel Martinez ◽  
Johane Bracamonte ◽  
Marco Gonzalez
Keyword(s):  
Boundary Element Method ◽  
Numerical Method ◽  
Bending Moment ◽  
Piping System ◽  
Thin Walled Structures ◽  
Out Of Plane ◽  
Thin Walled ◽  
Plane Bending ◽  
Flexibility Factor ◽  
Element Method

Flexibility Factor is an important parameter for the design of piping system related to oil, gas and power industry. Elbows give a great flexibility to piping system, but where a trunnion is attached to an elbow in order to support vertical pipe sections, the piping flexibility is affected. Generally, determination of elbow flexibility factors has been performed by engineering codes such as ASME B31.3 or ASME B31.8, or using the Finite Element Method (FEM) and Finite Difference Method (FDM). In this work, bend flexibility factors for 3D models of piping elbows and piping elbows with trunnion attachments using the Boundary Element Method (BEM) are calculated. The BEM is a relatively new numerical method for this kind of analysis, for which only the surface of the problem needs to be discretized into elements reducing the dimensionality of the problem. This paper shows the simulation of 9 elbows with commercially available geometries and 29 geometries of elbows with trunnion attachments, 10 of them using commercial elbow dimensions, with applied in-plane and out-of-plane bending moments. Structured meshes are used for all surfaces, except the contact surface of elbow-trunnion joints, and no welded joints are simulated. The results show smaller values of flexibility factors of elbow and elbow–trunnion attachments in all loading cases if are compared to ASME B31.3 or correlations obtained from other works. The results also indicate that flexibility factor for elbow-trunnion attachment subjected to in-plane bending moment is greater than flexibility factor for out-of plane bending moment. Accuracy of BEM’s results were not good when flexibility characteristic values are lesser than 0.300, which confirm the problems of this numerical method with very thin-walled structures. The method of limit element could be used as tool of alternative analysis for the design of made high-pitched system, when the problem with very thin-walled structures is fixed.

A Symmetric Galerkin Formulation of the Boundary Element Method for Acoustic Radiation and Scattering

1997 ◽  
Vol 05 (02) ◽  
pp. 219-241 ◽  
Author(s):  
Z. S. Chen ◽  
G. Hofstetter ◽  
H. A. Mang
Keyword(s):  
Boundary Element Method ◽  
Numerical Solution ◽  
Boundary Element ◽  
Integral Equations ◽  
Acoustic Radiation ◽  
Numerical Study ◽  
Three Dimensional ◽  
Galerkin Formulation ◽  
Thin Walled ◽  
Element Method

A symmetric Galerkin formulation of the Boundary Element Method for acoustic radiation and scattering is presented. The basic integral equations for radiation and scattering of sound are derived for structures, which may consist of a combination of a three-dimensional closed part and thin-walled parts. For the numerical solution of these integral equations a Galerkin-type numerical solution scheme is proposed. The evaluation of the weakly-singular and the hypersingular integrals, occurring in this formulation, is addressed briefly. An improved CHIEF-method is employed in order to prevent the singularity of the coefficient matrix of the algebraic system of equations at so-called irregular frequencies. Subsequently, an algorithm for the automatic determination of the number of nodal unknowns at intersections of thin-walled parts of a structure, or of thin-walled parts and the three-dimensional closed part of a structure, is described. The numerical study contains comparisons of analytical solutions for simple academic examples with the numerical results. In addition, a comparison of measured and computed results is presented for a structure, consisting of both a three-dimensional closed part and a thin-walled part.

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