共查询到20条相似文献,搜索用时 15 毫秒
1.
将弹性力学平面问题归化成无奇异边界积分方程,避免了传统的边界元法中的柯西主值(CPV)积分和Hadamard-Finite-Parts(HFP)积分的计算,建立完整的数值求解体系。 相似文献
2.
弹性力学平面问题的等价边界积分方程的边界轮廓法 总被引:5,自引:0,他引:5
基于边界积分方程中被积函数散度为零的特性,提出了弹性力学平面问题的等价边界积分方程的边界轮廓法,该方法无需进行数值积分,只需要计算单元两结点势函数值之差。实例计算说明,基于传统的边界积分方程的边界轮廓法所得到的面力结果是错误,而本文建立的边界轮廓法则可给出精确的结果。 相似文献
3.
Peter Schiavone 《Journal of Elasticity》1996,43(1):31-43
The boundary integral equation method is used to solve the interior and exterior Dirichlet, Neumann and mixed problems of plane micropolar elasticity. In the exterior case, a specific far-field pattern for the displacements and microrotation is introduced without which the classical scheme fails to work. Finally, we discuss the direct method and establish a connection with results obtained previously. 相似文献
4.
IntroductionIthasbeenratheralonghistorythattheBoundaryElementMethod (BEM )isappliedtosolvetheplaneelasticityproblems[1~2 ].However,theEBIE ,whichisequivalenttotheoriginalboundaryvalueproblem ,hasnotbeenfullyappreciatedandsolvedinBEMcommunity .TheconventionalboundaryintegralequationswithindirectvariablesarediscussedthoroughlyanditisshownthatthepreviousresultsarenotEBIE ,i.e .,sometimes,thereexistsnosolutionormorethanonesolutiontothem .Themainkeyliesintheexactformoftheexteriorproblems.I… 相似文献
5.
IntroductionTheclassicalconhnuummechanicshasbeenusedtosolvemanyproblemsinmacrofracturemechanics,butencountersdifficulheswhentheeffectofITilcrocharacteristicdimensionshouldbetakenintoaccount.Thestressfieldverynearthecracktipisstillnotclear.Somephenomenaofshortcrackscannotbeexplained["']andsomemechanismoffracturehasnotbeensolvedyet.Thenon-localelashcitytheoryseemsattractivetotheseproblems.Thetheoryofnon-localelasticity,establishedanddevelopedbyEringenetal[3),connectstheclassicalcontinuummechan… 相似文献
6.
本文讨论了二维和三维泊松方程中域积分化为边界积分的方法。对于形如x~ig_x(y,z)、y~ig_x(x,z)和z~ig_z(x,y)的荷载给出了域积分转化为边界积分的正确公式。而对于复杂荷载,利用泰勒展开将域积分近似地转化为边界积分并给出了误差估计。计算结果表明利用本文方法可大大节省计算时间。因此,本文方法是一种十分有效的方法。 相似文献
7.
By means of Fourier integral transformation of generalized fimction, the fimdamental solution for the bending problem of plales on two-parameter foundation is derived in this paper, and the fundamental solution is expanded into a uniformly convergent series.On the basis of the above work, two boundary integral eguations which are suitable to arhitrary shapes and arbitrary boundary conditions are established by means of the Rayleigh-Green identity. The content of the paper provides the powerful theories for the application of BEM in this problem. 相似文献
8.
Two fundamental solutions for bending problem of Reissner's plates on two-parameter foundation are derived by means of Fourier
integral transformation of generalized function in this paper. On the basis of virtual work principles, three boundar integral
equations which fit for arbitrary shapes, lods and boundary conditions of thick plates are presented according to Hu Haichang's
theory about Reissner's plates. It provides the fundamental theories for the application of BEM. A numerical example is given
for clamped, simply supported and free boundary conditions. The results obtained are satisfactory as compared with the analytical
methods.
Project supported by the P.H.D. Foundation of National Education Committee of China 相似文献
9.
Leonid K. Antanovskii 《Meccanica》1991,26(2-3):59-65
In this paper planar viscous flows with a free boundary are further studied using the quasisteady approximation [1]. The introduction of the bianalytical stress-stream function provides an opportunity to adopt the theory of analytical functions. The mode of construction of the Fredholm boundary integral equations is here proposed through the explicit solutions of two Hilbert problems for holomorphic functions with the application of the conformal mappings. The stabiligy of the equilibrium of the annulus liquid layer is investigated by way of example.
Sommario Si prosegue lo studio di flussi piani viscosi con frontiera libera applicando l'approssimazione quasistazionaria [1]. L'introduzione della funzione stress-stream bianalitica consente l'uso della teoria delle funzioni olomorfe. La costruzione delle equazioni integrali di Fredholm al contorno proposta qui si basa sulla risoluzione esplicita di due problemi di Hilbert per funzioni analitiche mediante applicazione della tecnica delle trasformazioni conformi. Come esempio si studia la stabilità dell'equilibrio di uno strato liquido anulare.相似文献
10.
Itisknownthatmostagriculturalproductsandfoodsareprocessedandtransportedundercertaintemperatureconditions,andthestructuralcomponentsalsoworkunderathermalenvironment.Temperatureinducedstressesusuallyleadtodamageofflawedsolids.Thus,theinvestigationofthecr… 相似文献
11.
A computational model is proposed for short-fiber reinforced materials with the eigenstrain formulation of the boundary integral equations(BIE)and solved with the newly developed boundary point method(BPM).The model is closely derived from the concept of the equivalent inclusion of Eshelby tensors.Eigenstrains are iteratively determined for each short.fiber embedded in the matrix with various properties via the Eshelby tensors,which can be readily obtained beforehand either through analytical or numerical means.As unknown variables appear only on the boundary of the solution domain,the solution scale of the inhomogeneity problem with the model is greatly reduced.This feature is considered significant because such a traditionally time-consuming problem with inhomogeneity can be solved most cost-effectively compared with existing numerical models of the FEM or the BEM.The numerical examples are presented to compute the overall elastic properties for various short-fiber reinforced composites over a representative volume element(RVE),showing the validity and the effectiveness of the proposed computational modal and the solution procedure. 相似文献
12.
A computational model is proposed for short-fiber reinforced materials with the eigenstrain formulation of the boundary integral equations (BIE) and solved with the newly developed boundary point method (BPM). The model is closely derived from the concept of the equivalent inclusion Of Eshelby tensors. Eigenstrains are iteratively determined for each short-fiber embedded in the matrix with various properties via the Eshelby tensors, which can be readily obtained beforehand either through analytical or numerical means. As unknown variables appear only on the boundary of the solution domain, the solution scale of the inhomogeneity problem with the model is greatly reduced. This feature is considered significant because such a traditionally time-consuming problem with inhomogeneity can be solved most cost-effectively compared with existing numerical models of the FEM or the BEM. The numerical examples are presented to compute the overall elastic properties for various short-fiber reinforced composites over a representative volume element (RVE), showing the validity and the effectiveness of the proposed computational modal and the solution procedure. 相似文献
13.
Summary The paper deals with numerical solutions of singular integral equations in stress concentration problems for longitudinal
shear loading. The body force method is used to formulate the problem as a system of singular integral equations with Cauchy-type
singularities, where unknown functions are densities of body forces distributed in the longitudinal direction of an infinite
body. First, four kinds of fundamental density functions are introduced to satisfy completely the boundary conditions for
an elliptical boundary in the range 0≤φ
k
≤2π. To explain the idea of the fundamental densities, four kinds of equivalent auxiliary body force densities are defined
in the range 0≤φ
k
≤π/2, and necessary conditions that the densities must satisfy are described. Then, four kinds of fundamental density functions
are explained as sample functions to satisfy the necessary conditions. Next, the unknown functions of the body force densities
are approximated by a linear combination of the fundamental density functions and weight functions, which are unknown. Calculations
are carried out for several arrangements of elliptical holes. It is found that the present method yields rapidly converging
numerical results. The body force densities and stress distributions along the boundaries are shown in figures to demonstrate
the accuracy of the present solutions.
Received 26 May 1998; accepted for publication 27 November 1998 相似文献
14.
15.
Stochastic boundary element method in elasticity 总被引:1,自引:0,他引:1
The stochastic boundary element method is developed to analyze elasticity problems with random material and/or geometrical
parameters and randomly perturbed boundaries. Based on the first-order Taylor series expansion, the boundary integration equations
concerning the mean and deviation of the displacements are derived, respectively. It is found that the randomness of material
parameters is equivalent to a random body force, so the mean and covariance matrices of unknown boundary displacements and
tractions can be obtained. Furthermore, the mean and covariance of displacements and stresses at inner points can also be
obtained. Numerical examples show that the proposed stochastic boundary element method gives satisfactory solutions, as compared
with those obtained by theoretical analysis or other numerical methods.
The project supported by the National Natural Science Foundation of China and the State Education Commission Foundation of
China 相似文献
16.
Yang Zuosheng 《国际流体数值方法杂志》2005,47(12):1423-1430
A complete boundary integral formulation for compressible Navier–Stokes equations with time discretization by operator splitting is developed using the fundamental solutions of the Helmholtz operator equation with different order. The numerical results for wall pressure and wall skin friction of two‐dimensional compressible laminar viscous flow around airfoils are in good agreement with field numerical methods. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
17.
The stress rate integral equations of elastoplaticity are deduced based on Ref. [1] by consistent methods. The point at which
the stresses and/or displacements are calculated can be in the body or on the boundary, and in the plastic region or elastic
one. The existence of the principal value integral in the plastic region is demonstrated strictly, and the theoretical basis
is presented for the paticular solution method by unit initial stress fields. In the present method, programming is easy and
general, and the numerical results are excellent.
The project supported by the National Natural Science Foundation of China 相似文献
18.
19.
Because exact analytic solution is not available,we use double expansion and boundary collocation to construct an approximate solution for a class of two-dimensional dual integral equations in mathematical physics.The integral equations by this procedure are reduced to infinite algebraic equations.The accuracy of the solution lies in the boundary collocation technique.The application of which for some complicated initial- boundary value problems in solid mechanics indicates the method is powerful. 相似文献
20.
Hai-Chang Hu 《Acta Mechanica Solida Sinica》1989,2(2):213-219
A necessary and sufficient condition for the correct formulation of boundary integral equations of harmonic functions is established in the present paper. A super-determined problem of harmonic functions is proposed for the first time. Then a necessary and sufficient condition for the existence of solution of the super-determined problem is proved. At the same time, it is a necessary and sufficient condition for the correct formulation of boundary integral equations with direct unknown quantities. A relation between boundary integral equations and variational principles is discovered for the first time. And a one-to-one correspondence between boundary integral equations with direct and indirect unknown quantities is indicated. The concept and route of the present paper can be applied to other boundary value problems possessing variational principles. 相似文献