摘要:

AbstractA discrete momentum‐conserving, explicit time integration is presented. The accurate feature and simplicity of the present algorithm are realized by a mid‐point implicit formula for integrating the Euler parameters and a second‐order discrete momentum‐conserving form of the central difference algorithm, respectively. The accuracy and robustness of the algorithm is demonstrated by example problems which exhibit large overall rigid motions under holonomic cons

ISSN:0029-5981    

DOI:10.1002/nme.1620360702

出版商:John Wiley&Sons, Ltd    

年代:1993

数据来源: WILEY

摘要:

AbstractThe problem of multilayered degenerated 3‐D shell elements for which the numerical integration is performed for each ply is that of the high generation time in non‐linear analysis when the number of plies is important. But these elements give accurate results for thin and moderately thick shells, so in order to reduce the generation time explicit thickness integration is investigated. We first write an expansion of the strain‐displacement matrix in power series of the thickness variable in order to obtain explicit expressions of the tangent stiffness matrix and internal force vector, appearing in the non‐linear formulation. Explicit expressions of non‐linear stiffness matrices are presented, using the explicit integration‐first approximation. Simple expressions of several matrices, sub‐matrices and vectors appearing in the formulation are given here in order to obtain an important computing‐time gain. Next, some numerical validation tests comparing the classical element with numerical thickness integration and this one are discussed to prove validity of t

ISSN:0029-5981    

DOI:10.1002/nme.1620360703

出版商:John Wiley&Sons, Ltd    

年代:1993

数据来源: WILEY

摘要:

AbstractThe Arbitrary‐Lagrange‐Euler (ALE) formulation is applied to the analysis of unsteady viscoelastic flow of an Upper‐Convected‐Maxwell (UCM) medium. It is shown how the requirement ofincremental objectivityaffects the stress updating scheme. The current implementation of the ALE formulation uses the Time‐Discontinuous/Galerkin‐Least‐Squares (TD/GLS) method to handle the advective parts of the equations. Further, the ALE formulation is compared with an Updated‐ALE formulation that is shown to give comparable results but is much more cost effective. The technique presented is particularly effective for free surface flows. Three applica

ISSN:0029-5981    

DOI:10.1002/nme.1620360704

出版商:John Wiley&Sons, Ltd    

年代:1993

数据来源: WILEY

摘要:

AbstractBased on the theory of micropolar elasticity, new degenerated shell elements with drilling degree of freedoms are presented. The proper stiffness on the drilling degree of freedom is derived and no spurious modes are encountered in these elements. The implementation of these new shell elements on general structural finite element programs has many advantages, especially for the analysis of a folded shell or the treatment of the twist moment normal to the shell. Several numerical examples are carried out to demonstrate the accuracy and applicability of the present elements. The effects of the coupling factor and the body moment induced in magneto‐solid mechanics are also studie

ISSN:0029-5981    

DOI:10.1002/nme.1620360705

出版商:John Wiley&Sons, Ltd    

年代:1993

数据来源: WILEY

摘要:

AbstractA triangular geometrically non‐linear constant stress element is presented, applicable to thin‐shell problems involving finite rotations. The element has the same degrees of freedom as the linear element following from the superposition of the constant strain triangle and the constant moment triangle. In the derivation of the non‐linear strain‐displacement relations, special attention is given to the correct representation of the rigid body motions of a patch of elements. Based on a second‐order out‐of‐plane displacement field, an initial deflection is introduced. This improves the effectiveness of the element, since curved shell geometries can be described more accurately. Several demonstrative examples

ISSN:0029-5981    

DOI:10.1002/nme.1620360706

出版商:John Wiley&Sons, Ltd    

年代:1993

数据来源: WILEY

摘要:

AbstractIn this paper a finite element method for geometrically and materially non‐linear analyses of space frames is described. Beams with both solid and thin‐walled open cross‐sections are considered. The equations of equilibrium are formulated using an updated incremental Lagrangian description. The elements developed can undergo large displacements and rotations, but the incremental rotations are assumed to be small. The material behaviour is described by elastoplastic, temperature‐dependent elastoplastic and viscoplastic models with special reference to metals. Computationally, more economical formulations based on the relationship between stress resultants and generalized strain quantities are also presented. In the case of thin‐walled beams the torsional behaviour is modelled using a two‐parameter warping model, where the angle of twist and the axial variation of warping have independent approximations. This approach yields average warping shear strains directly from the displacement assumptions and no discrepancy between stress and strain fi

ISSN:0029-5981    

DOI:10.1002/nme.1620360707

出版商:John Wiley&Sons, Ltd    

年代:1993

数据来源: WILEY

摘要:

AbstractThis paper presents a simple and thorough technique to examine the general behaviour of two‐dimensional (2‐D) 8‐node and 3‐D 20‐node isoparametric elements, collapsed at one side. With this method the conditions for the well‐known quarter‐point and half‐point elements, frequently used in fracture mechanics applications to model the crack tip behaviour, are arrived at in a natural way. It also allows for an in‐depth analysis of the Jacobian determinant, and can easily be applied to other

ISSN:0029-5981    

DOI:10.1002/nme.1620360708

出版商:John Wiley&Sons, Ltd    

年代:1993

数据来源: WILEY

ISSN:0029-5981    

DOI:10.1002/nme.1620360709

出版商:John Wiley&Sons, Ltd    

年代:1993

数据来源: WILEY

ISSN:0029-5981    

DOI:10.1002/nme.1620360710

出版商:John Wiley&Sons, Ltd    

年代:1993

数据来源: WILEY

ISSN:0029-5981    

DOI:10.1002/nme.1620360701

出版商:John Wiley&Sons, Ltd    

年代:1993

数据来源: WILEY