摘要:

AbstractWe employ a finite element method to consider the numerical solution of Aifantis' equations of double porosity.1–5The physical and mathematical foundations of the theory of double porosity were considered in two previous papers,6,7where analytical solutions of the relevant equations are also given. For practical purposes and for the completeness of the presentation, we re‐derive the basic equations without resorting to the more rigorous scheme of multiporosity theory.1–6Instead, we follow the more familiar approach of Biot8,9which we now extend from the case of single porosity to the case of double porosity. Then a general finite element formulation of the relevant eqations is thoroughly discussed and explicitly described for the two‐dimensional case where four‐node rectangular non‐conforming isoparametric elements are employed. Three numerical examples are presented in detail to illustrate the method and assess the differences between single and double porosity models in co

ISSN:0363-9061    

DOI:10.1002/nag.1610080202

出版商:John Wiley&Sons, Ltd    

年代:1984

数据来源: WILEY

摘要:

AbstractAn analytical solution for rapid (undrained) expansion of a long cylindrical cavity from initially zero radius is presented. A simple rate‐type soil model possessing the salient features of the modified Cambridge critical state model is used. Application of the solution to determination of the stress field surrounding a pile immediately after driving is discusse

ISSN:0363-9061    

DOI:10.1002/nag.1610080203

出版商:John Wiley&Sons, Ltd    

年代:1984

数据来源: WILEY

摘要:

AbstractThe stress and deformation resulting from rapidly applied axial traction on the face of a cylindrical cavity in a saturated soil are analysed. A simple rate‐type constitutive model is used for the effective stress respons

ISSN:0363-9061    

DOI:10.1002/nag.1610080204

出版商:John Wiley&Sons, Ltd    

年代:1984

数据来源: WILEY

摘要:

AbstractThis paper examines the problem of the flexure of a strip of finite width which is embedded in bonded contact with an isotropic elastic medium of infinite extent. The analysis of the problem is applicable to flexible beams of narrow width which experience flexure only in the longitudinal direction. Numerical results are developed for the maximum flexural moment induced in the embedded beam due to the action of a concentrated force.

ISSN:0363-9061    

DOI:10.1002/nag.1610080205

出版商:John Wiley&Sons, Ltd    

年代:1984

数据来源: WILEY

摘要:

AbstractThe restrictions imposed by the form‐invariance principle on the structure of the elasto‐plastic constitutive law for small strains are examined. It is shown that the yield and plastic potential functions may depend on the joint invariants of the stress and plastic strain tensors in addition to their dependence on the direct invariants of these tensors and additional scalar hardening parameters such as the plastic work; inclusion of the joint invariants as parameters in the constitutive functions allows for induced anisotropy during plastic deformation. It is demonstrated that the physical meaning of the joint invariants is related to the deviation of the principal directions of the stress tensor from those of the plastic strain tensor. It is also shown that only three cases of anisotropy (orthorhombic, transverse and isotropy) are possible in the types of material models discussed herein. The model proposed in this paper does not imply coaxiality between the principal directions of the stress and, plastic strain increment tensors; however, implications of the assumption of coaxiality on the structure of the constitutive equations is investigated. It is shown that coaxiality does not necessarily imply isotropy, but no deviations from coaxiality can be expected in isotropic materi

ISSN:0363-9061    

DOI:10.1002/nag.1610080206

出版商:John Wiley&Sons, Ltd    

年代:1984

数据来源: WILEY

摘要:

AbstractLocalization of deformation in elastic‐plastic solids subject to plane strain deformation are investigated numerically. It is shown that the localization may be captured accurately in finite element models by employing (1) the elastic‐plastic material stiffness to form the global stiffness, (2) in the case of symmetrical configurations, an imperfection in the form of a weak element, and (3) in the case of incompressible materials, a reduced selective integration scheme which alleviates mesh ‘locking’. Accuracy of the technique is demonstrated by applying it to analyse the classical punch and slope stability problems. Its versatility is illustrated by applying it to analyse finite deformation problems and shear bands formations in associative and non‐associative elastic‐pla

ISSN:0363-9061    

DOI:10.1002/nag.1610080207

出版商:John Wiley&Sons, Ltd    

年代:1984

数据来源: WILEY

ISSN:0363-9061    

DOI:10.1002/nag.1610080208

出版商:John Wiley&Sons, Ltd    

年代:1984

数据来源: WILEY

ISSN:0363-9061    

DOI:10.1002/nag.1610080201

出版商:John Wiley&Sons, Ltd    

年代:1984

数据来源: WILEY