Built upon the two original books by Mike Crisfield and their own lecture notes, renowned scientist Rene de Borst and his team offer a thoroughly updated yet condensed edition that retains and builds upon the excellent reputation and appeal amongst students and engineers alike for which Crisfield's first edition is acclaimed. Together with numerous additions and updates, the new authors have retained the core content of the original publication, while bringing an improved focus on new developments and ideas. This edition offers the latest insights in non-linear finite element technology, including non-linear solution strategies, computational plasticity, damage mechanics, time-dependent effects, hyperelasticity and large-strain elasto-plasticity. The authors' integrated and consistent style and unrivalled engineering approach assures this book's unique position within the computational mechanics literature.

Non-Linear Finite Element Analysis of Solids and Structures: de Borst/Non-Linear Finite Element Analysis of Solids and Structures

This paper gives an extensive documentation of applications of finite-dimensional nonlinear complementarity problems in engineering and equilibrium modeling. For most applications, we describe the problem briefly, state the defining equations of the model, and give functional expressions for the complementarity formulations. The goal of this documentation is threefold: (i) to summarize the essential applications of the nonlinear complementarity problem known to date, (ii) to provide a basis for the continued research on the nonlinear complementarity problem, and (iii) to supply a broad collection of realistic complementarity problems for use in algorithmic experimentation and other studies.

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Engineering and Economic Applications of Complementarity Problems

A review of techniques, advances and outstanding issues in numerical modelling for rock mechanics and rock engineering

In heterogeneous materials such as concretes or rocks, failure occurs by progressive distributed damage during which the material exhibits strain‐softening, i.e., a gradual decline of stress at increasing strain. It is shown that strain‐softening which is stable within finite‐size regions and leads to a nonzero energy dissipation by failure can be achieved by a new type of nonlocal continuum called the imbricate continuum. Its theory is based on the hypothesis that the stress depends on the change of distance between two points lying a finite distance apart. This continuum is a limit of a discrete system of imbricated (regularly overlapping) elements which have a fixed length, l, and a cross‐section area that tends to zero as the discretization is refined. The principal difference from the existing nonlocal continuum theory is that the equation of motion involves not only the averaging of strains but also the averaging of stress gradients. This assures that the finite element stiffness matrices are symmet...

Continuum Theory for Strain‐Softening

Classical continuum models, i.e. continuum models that do not incorporate an internal length scale, suffer from excessive mesh dependence when strain‐softening models are used in numerical analyses and cannot reproduce the size effect commonly observed in quasi‐brittle failure. In this contribution three different approaches will be scrutinized which may be used to remedy these two intimately related deficiencies of the classical theory, namely (i) the addition of higher‐order deformation gradients, (ii) the use of micropolar continuum models, and (iii) the addition of rate dependence. By means of a number of numerical simulations it will be investigated under which conditions these enriched continuum theories permit localization of deformation without losing ellipticity for static problems and hyperbolicity for dynamic problems. For the latter class of problems the crucial role of dispersion in wave propagation in strain‐softening media will also be highlighted.

/pdf/fundamental-issues-in-finite-element-analyses-of-1y8oca8s57.pdf

Fundamental issues in finite element analyses of localization of deformation

General piecewise linear constitutive laws with associated flow rules are formulated in matrix notation; some properties and specializations (in particular to kinematic and isotropic hardening) are discussed. With reference to finite element models of structures and, hence, in matrix-vector description, the following results are achieved: 
a) the holonomic solutions to the analysis problem for given loads and dislocations are shown to be characterized by means of six “quadratic-linear” minimum principles, two of general, four of conditioned validity;b) the incremental counterparts of the above theorems are indicated by analogy; some comparison properties concerning holonomic and nonholonomic solutions, are pointed out;c) a shakedown theorem is established for variable repeated loads and dislocations, with allowance for inertia forces and viscous damping, i. e. a generalization to workhardening structures of Ceradini's and (in quasi-static situations) Melan's theorems;d) a method is proposed for evaluating under holonomy hypothesis, or bounding from above, the safety factor with respect to local failure due to limited plastic strain capacity.

/pdf/a-matrix-structural-theory-of-piecewise-linear-1p8n84mar9.pdf

A matrix structural theory of piecewise linear elastoplasticity with interacting yield planes

This review article concerns a methodology for solving numerically, for engineering purposes, boundary and initial-boundary value problems by a peculiar approach characterized by the following features: the continuous formulation is centered on integral equations based on the combined use of single-layer and double-layer sources, so that the integral operator turns out to be symmetric with respect to a suitable bilinear form. The discretization is performed either on a variational basis or by a Galerkin weighted residual procedure, the interpolation and weight functions being chosen so that the variables in the approximate formulation are generalized variables in Prager’s sense. As main consequences of the above provisions, symmetry is exhibited by matrices with a key role in the algebraized versions; some quadratic forms have a clear energy meaning; variational properties characterize the solutions and other results, invalid in traditional boundary element methods enrich the theory underlying the computational applications. The present survey outlines recent theoretical and computational developments of the title methodology with particular reference to linear elasticity, elastoplasticity, fracture mechanics, time-dependent problems, variational approaches, singular integrals, approximation issues, sensitivity analysis, coupling of boundary and finite elements, and computer implementations. Areas and aspects which at present require further research are identified, and comparative assessments are attempted with respect to traditional boundary integral-elements. This article includes 176 references.

https://hal.archives-ouvertes.fr/hal-00111259/document

Symmetric Galerkin Boundary Element Methods

https://people.duke.edu/~hueckel/papers/MaierHueckel1979.pdf

Nonassociated and coupled flow rules of elastoplasticity for rock-like materials

The matrix description of the mechanical behaviour resting on finite element discretization and piecewise linearization of yield surfaces, is adopted instead of the traditional continuous field description. By the use of linear programming concepts, the essential of a general shakedown theory and the basis of relevant solution procedures are presented in compact form. For systems with associated flow-laws, the second shakedown theorem (Koiter's) is extended in order to allow for variable dislocations (e. g. temperature cycles). For systems with nonassociated flow-laws two theorems are given which supply lower and upper bounds to the safety factor.

Shakedown theory in perfect elastoplasticity with associated and nonassociated flow-laws: A finite element, linear programming approach

A “symmetric” boundary element method based on a weighted residual Galerkin approach for elastoplastic analysis is revisited and its computer implementation for two-dimensional homogeneous problems is described.

G. Maier

Papers

A matrix structural theory of piecewise linear elastoplasticity with interacting yield planes

Symmetric Galerkin Boundary Element Methods

Nonassociated and coupled flow rules of elastoplasticity for rock-like materials

Shakedown theory in perfect elastoplasticity with associated and nonassociated flow-laws: A finite element, linear programming approach

A galerkin symmetric boundary‐element method in elasticity: Formulation and implementation