CMES-Vol. 2, No. 4, 2001

Open Access

ARTICLE

A Pure Contour Formulation for the Meshless Local Boundary Integral Equation Method in Thermoelasticity
J. Sladek¹, V. Sladek¹, S.N. Atluri²
CMES-Computer Modeling in Engineering & Sciences, Vol.2, No.4, pp. 423-434, 2001, DOI:10.3970/cmes.2001.002.423
Abstract A new meshless method for solving stationary thermoelastic boundary value problems is proposed in the present paper. The moving least square (MLS) method is used for the approximation of physical quantities in the local boundary integral equations (LBIE). In stationary thermoelasticity, the temperature and displacement fields are uncoupled. In the first step, the temperature field, described by the Laplace equation, is analysed by the LBIE. Then, the mechanical quantities are obtained from the solution of the LBIEs, which are reduced to elastostatic ones with redefined body forces due to thermal loading. The domain integrals with More >

View
1652

Download
1353
Open Access

ARTICLE

Steady Heat Conduction Analysis in Orthotropic Bodies by Triple-reciprocity BEM
Y. Ochiai
CMES-Computer Modeling in Engineering & Sciences, Vol.2, No.4, pp. 435-446, 2001, DOI:10.3970/cmes.2001.002.435
Abstract The boundary element method (BEM) is useful in solving the steady heat conduction problem of orthotropic bodies without heat generation. However, for cases with arbitrary heat generation, a number of internal cells are necessary. In this paper, it is shown that the problem of steady heat conduction in orthotropic bodies with heat generation can be solved without internal cells by the triple-reciprocity BEM. In this method, the distribution of heat generation is interpolated using integral equations. In order to solve the problem, the values of heat generation at internal points and on the boundary are More >

View
1563

Download
1365
Open Access

ARTICLE

On the Equivalence Between Least-Squares and Kernel Approximations in Meshless Methods
Xiaozhong Jin¹, Gang Li², N. R. Aluru³
CMES-Computer Modeling in Engineering & Sciences, Vol.2, No.4, pp. 447-462, 2001, DOI:10.3970/cmes.2001.002.447
Abstract Meshless methods using least-squares approximations and kernel approximations are based on non-shifted and shifted polynomial basis, respectively. We show that, mathematically, the shifted and non-shifted polynomial basis give rise to identical interpolation functions when the nodal volumes are set to unity in kernel approximations. This result indicates that mathematically the least-squares and kernel approximations are equivalent. However, for large point distributions or for higher-order polynomial basis the numerical errors with a non-shifted approach grow quickly compared to a shifted approach, resulting in violation of consistency conditions. Hence, a shifted polynomial basis is better suited from More >

View
1597

Download
1098
Open Access

ARTICLE

A Meshless Local Petrov-Galerkin (MLPG) Formulation for Static and Free Vibration Analyses of Thin Plates
Y. T. Gu, G. R. Liu¹
CMES-Computer Modeling in Engineering & Sciences, Vol.2, No.4, pp. 463-476, 2001, DOI:10.3970/cmes.2001.002.463
Abstract A meshless method for the analysis of Kirchhoff plates based on the Meshless Local Petrov-Galerkin (MLPG) concept is presented. A MLPG formulation is developed for static and free vibration analyses of thin plates. Local weak form is derived using the weighted residual method in local supported domains from the 4th order partial differential equation of Kirchhoff plates. The integration of the local weak form is performed in a regular-shaped local domain. The Moving Least Squares (MLS) approximation is used to constructed shape functions. The satisfaction of the high continuity requirements is easily met by MLS More >

View
1616

Download
1376
Open Access

ARTICLE

2.5D Green's Functions for Elastodynamic Problems in Layered Acoustic and Elastic Formations
António Tadeu, Julieta António¹
CMES-Computer Modeling in Engineering & Sciences, Vol.2, No.4, pp. 477-496, 2001, DOI:10.3970/cmes.2001.002.477
Abstract This paper presents analytical solutions, together with explicit expressions, for the steady state response of homogeneous three-dimensional layered acoustic and elastic formations subjected to a spatially sinusoidal harmonic line load. These formulas are theoretically interesting in themselves and they are also useful as benchmark solutions for numerical applications. In particular, they are very important in formulating three-dimensional elastodynamic problems in layered fluid and solid formations using integral transform methods and/or boundary elements, avoiding the discretization of the solid-fluid interfaces. The proposed Green's functions will allow the solution to be obtained for high frequencies, for which More >

View
1823

Download
1328
Open Access

ARTICLE

Element Free Galerkin Method for Three-dimensional Structural Analysis
Wen-Hwa Chen¹, Xhu-Ming Guo²
CMES-Computer Modeling in Engineering & Sciences, Vol.2, No.4, pp. 497-508, 2001, DOI:10.3970/cmes.2001.002.497
Abstract An Element Free Galerkin Method is developed for the analysis of three-dimensional structures. A highly accurate and reliable relation between the number of the quadrature orders n_Q and nodes in a three-dimensional cell n_c, n_Q ≥ ³√n_c + 3, is established to accomplish the required integral calculation in the cell. Based on the theory of topology, the generation of nodes in the solution procedure consists of three sequential steps, say, defining the geometric boundary, arranging inside of the body, and improving numerical accuracy. In addition, by selecting the Dirac Delta function as the weighting function, a three-dimensional More >

View
1473

Download
1093
Open Access

ARTICLE

An Improved Contact Algorithm for the Material Point Method and Application to Stress Propagation in Granular Material
S.G. Bardenhagen¹, J.E. Guilkey², K.M. Roessig³, J.U. Brackbill⁴, W.M. Witzel⁵, J.C.Foster⁶
CMES-Computer Modeling in Engineering & Sciences, Vol.2, No.4, pp. 509-522, 2001, DOI:10.3970/cmes.2001.002.509
Abstract Contact between deformable bodies is a difficult problem in the analysis of engineering systems. A new approach to contact has been implemented using the Material Point Method for solid mechanics, Bardenhagen, Brackbill, and Sulsky (2000a). Here two improvements to the algorithm are described. The first is to include the normal traction in the contact logic to more appropriately determine the free separation criterion. The second is to provide numerical stability by scaling the contact impulse when computational grid information is suspect, a condition which can be expected to occur occasionally as material bodies move through… More >

View
3009

Download
1671
Open Access

ARTICLE

Optimization of a Low Reynolds Number Airfoil with Flexible Membrane
Ori Levin, Wei Shyy¹
CMES-Computer Modeling in Engineering & Sciences, Vol.2, No.4, pp. 523-536, 2001, DOI:10.3970/cmes.2001.002.523
Abstract Typical low Reynolds number airfoils suffer from reduced lift-to-drag ratio and are prone to flow separation. In order to improve the aerodynamic performance of such airfoils in an unsteady freestream, the concept of passive control is investigated. In this study, a membrane with varying thickness distribution and mechanical properties is attached on the upper surface of a modified Clark-Y airfoil and is free to move upwards and downwards in response to the pressure difference across it. The response surface method is employed to investigate the individual and collective effects of the membrane's prestress, elastic modulus, More >

View
1584

Download
1262

Per Page:

View

1652

Download

1353

View

1563

Download

1365

View

1597

Download

1098

View

1616

Download

1376

View

1823

Download

1328

View

1473

Download

1093

View

3009

Download

1671

View

1584

Download

1262

Further Information

Guidelines

Follow Us

Join Us

Contact Us

WhatsApp:

Share Link