Library

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    A superlinear convergent augmented Lagrangian procedure for contact problems (1999)
    Bradford : Emerald
    Engineering computations 16 (1999), S. 88-119 
    Details
    ISSN: 0264-4401
    Source: Emerald Fulltext Archive Database 1994-2005
    Topics: Technology
    Notes: The numerical solution of contact problems via the penalty method yields approximate satisfaction of contact constraints. The solution can be improved using augmentation schemes. However their efficiency is strongly dependent on the value of the penalty parameter and usually results in a poor rate of convergence to the exact solution. In this paper we propose a new method to perform the augmentations. It is based on estimated values of the augmented Lagrangians. At each augmentation the converged state is used to extract some data. Such information updates a database used for the Lagrangian estimation. The prediction is primarily based on the evolution of the constraint violation with respect to the evolution of the contact forces. The proposed method is characterised by a noticeable efficiency in detecting nearly exact contact forces, and by superlinear convergence for the subsequent minimisation of the residual of constraints. Remarkably, the method is relatively insensitive to the penalty parameter. This allows a solution which fulfils the constraints very rapidly, even when using penalty values close to zero.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1108/02644409910251292
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Comparison of different error estimators for contact problems (2000)
    Bradford : Emerald
    Engineering computations 17 (2000), S. 255-273 
    Details
    ISSN: 0264-4401
    Source: Emerald Fulltext Archive Database 1994-2005
    Topics: Technology
    Notes: Several a posteriori error indicators and error estimators for frictionless contact problems are compared. In detail, residual based error estimators, error indicators relying on superconvergence properties and error estimators based on duality principles are investigated. Applications are to 2D solids under the hypothesis of nonlinear elastic material behaviour associated with finite deformations. A penalization technique is applied to enforce multilateral boundary conditions due to contact. The approximate solution of the problem is obtained by using the finite element method. Several numerical results are reported to show the applicability of the adaptive algorithm to the considered problems.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1108/02644400010324884
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    An algebraic multigrid solver for finite element computations in solid mechanics (1997)
    Bradford : Emerald
    Engineering computations 14 (1997), S. 202-215 
    Details
    ISSN: 0264-4401
    Source: Emerald Fulltext Archive Database 1994-2005
    Topics: Technology
    Notes: Presents an implementation of the algebraic multigrid method. It can work in two ways: as pure multigrid method and as a pre-conditioner for the conjugate gradient method. Shows applications of the iterative solvers for problems in linear and non-linear elasticity. Shows the range of possible applications with different examples with regular and non-regular meshes and three-dimensional problems.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1108/02644409710166181
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Comparative crash simulations incorporating the results of sheet forming analyses (2001)
    Bradford : Emerald
    Engineering computations 18 (2001), S. 744-758 
    Details
    ISSN: 0264-4401
    Source: Emerald Fulltext Archive Database 1994-2005
    Topics: Technology
    Notes: To obtain more reliable crash simulations the history of the structure related to the forming process is considered. For this goal the variables defining the current state have to be transferred from one mesh to the other in order to maintain a consistent discretization of the whole structure consisting of several pre-formed parts. This is accomplished here by remeshing the structure after the forming process and by transferring the current mechanical properties. In performing such a transfer a numerical error cannot be avoided; the results of this approach are therefore compared with computations in which this transfer is not applied to assess the performance of the presented procedure.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1108/EUM0000000005786
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Direct computation of instability points with inequality constraints using the FEM (2003)
    Bradford : Emerald
    Engineering computations 20 (2003), S. 611-628 
    Details
    ISSN: 0264-4401
    Source: Emerald Fulltext Archive Database 1994-2005
    Topics: Technology
    Notes: The subject of this paper is the computation of instability points in mechanical problems with the finite element method. The objective is to extend the application of critical point detection methods to problems with inequality constraints originating from damage and contact. A simple bilinear model is considered for the damage problems. A bilateral, frictionless contact formulation is used for the contact problems. Among the critical point detection methods the focus is laid on the critical displacement method and the extended system. At first a possible combination of both methods is evaluated by applying them to damage problems. A prediction method based on the extended system is developed to facilitate the comparison of both methods. Secondly, the extended system is used as a computation method for critical points in two-dimensional contact problems.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1108/02644400310488781
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Combination of the critical displacement method with a damage model for structural instability analysis (2001)
    Bradford : Emerald
    Engineering computations 18 (2001), S. 642-662 
    Details
    ISSN: 0264-4401
    Source: Emerald Fulltext Archive Database 1994-2005
    Topics: Technology
    Notes: The paper describes the extension of the critical displacement method (CDM), presented by Oñate and Matias in 1996, to the instability analysis of structures with non-linear material behaviour using a simple damage model. The extended CDM is useful to detect instability points using a prediction of the critical displacement field and a secant load-displacement relationship accounting for material non-linearities. Examples of application of CDM to the instability analysis of structures using bar and solid finite elements are presented.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1108/02644400110387190
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Modeling and simulation of the decohesion of particulate aggregates in a binding matrix (2001)
    Bradford : Emerald
    Engineering computations 18 (2001), S. 79-95 
    Details
    ISSN: 0264-4401
    Source: Emerald Fulltext Archive Database 1994-2005
    Topics: Technology
    Notes: A model for the decohesion of aggregates of suspended particulate material in a binding matrix is developed. In the model cohesive zones which envelop each particle individually are introduced at the particulate/binder interface. During progressive loading, the deterioration of the cohesive zones is initiated if constraints placed on the microstress fields are violated. In order for the material behavior to be energetically admissible, the deterioration of the material at a point is in the form of a reduction of the elasticity tensor's eigenvalues at that point. The material within the cohesive zones deteriorates until the constraints are met. In order to isolate and study the effects of interfacial deterioration, outside of the cohesive zones, the material is unaltered. Mathematical properties of the model, as well as physical restrictions, are discussed. Numerical simulations are performed employing the finite element method to illustrate the approach in three-dimensional applications.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1108/02644400110365824
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Nonlinear stability-analysis of shell and contact-problems including branch-switching (1990)
    Springer
    Computational mechanics 5 (1990), S. 428-446 
    Details
    ISSN: 1432-0924
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract In the analysis of nonlinear elastic shells often the stability and postbuckling behaviour governs the response. Here we discuss problems which also include contact constraints. A nonlinear cylindrical shell element is derived directly from the associated shell theory using one point integration and a stabilization technique. Within a general solution algorithm a simple but effective branch-switching procedure is presented. Additional considerations allow the treatment of bifurcation problems with contact constraints. Several examples of beam and shell problems show the performance of the developed algorithms and elements.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01113447
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    On enhanced strain methods for small and finite deformations of solids (1996)
    Springer
    Computational mechanics 18 (1996), S. 413-428 
    Details
    ISSN: 1432-0924
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Numerical simulations of engineering problems require robust elements. For a broad range of applications these elements should perform well in bending dominated situations and also in cases of incompressibility. The element should be insensitive against mesh distortions which frequently occur due to modern mesh generation tools or during finite deformations. Possibly the elements should not lock in the thin limits and thus be applicable to shell problems. Furthermore due to efficiency reasons a good coarse mesh accuracy is required in nonlinear analysis. In this paper we discuss the family of enhanced strain elements in order to depict the positive and negative aspects related to these elements. Throughout this discussion we use numerical examples to underline the theoretical results.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00350250
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    An adaptive finite element algorithm for contact problems in plasticity (1995)
    Springer
    Computational mechanics 17 (1995), S. 88-97 
    Details
    ISSN: 1432-0924
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract  Due to the fact that in contact problems the contact area is not known a priori, a sufficient discretization to obtain a convergent finite element solution cannot be supplied from the outset. Therefore it is necessary to use adaptive finite element methods to adjust automatically the mesh sizes not only in the bodies under consideration but also in the contact zone. In this paper we develop an adaptive method for geometrically linear contact problems, which also includes elastoplastic material behavior. The radial return algorithm is used to derive the error estimator for one time increment of the solution process. The error estimator is based on the Zienkiewicz–Zhu projection scheme, which is extended to account for the special situation in the contact interface.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00356481
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...