Showing papers in "Computer Methods in Applied Mechanics and Engineering in 2007"

TL;DR: The main focus will be on the different approaches to perform robust optimization in practice including the methods of mathematical programming, deterministic nonlinear optimization, and direct search methods such as stochastic approximation and evolutionary computation.

TL;DR: In this paper, an LES-type variational multiscale theory of turbulence is presented, which derives completely from the incompressible Navier-Stokes equations and does not employ any ad hoc devices such as eddy viscosities.

TL;DR: In this paper, a new approach for modeling discrete cracks in mesh-free particle methods in 3D is described, where cracks can be arbitrarily oriented, but their growth is represented by activation of crack surfaces at individual particles, so no representation of the crack's topology is needed.

TL;DR: In this article, the effects of smoothness of basis functions on solution accuracy within the isogeometric analysis framework were investigated. And they concluded that the potential for the k-method is high, but smoothness is an issue that is not well understood due to the historical dominance of C 0 -continuous finite elements.

TL;DR: In this paper, a NURBS-based variational formulation for the Cahn-Hilliard equation was tested on two-dimensional and three-dimensional problems, and steady state solutions in two-dimensions and, for the first time, in threedimensions were presented.

TL;DR: In this article, a discrete representation of the added mass operatorMA is given and ''instability conditions'' are evaluated for different temporal discretisation schemes and it is proven that for every sequentially staggered scheme and given spatial discretization of a problem, a mass ratio between fluid and structural mass density can be found at which the coupled system becomes unstable.

TL;DR: In this article, an approach to construct hexahedral solid NURBS (non-uniform rational B-splines) meshes for patient-specific vascular geometric models from imaging data for use in isogeometric analysis is described.

TL;DR: In this paper, higher-order Non-Uniform Rational B-Splines (NURBS) are used for non-linear elasticity and plasticity analysis. But they are not suitable for the case of large deformation.

TL;DR: A review and state of the art of these methods can be found in this article, which discusses their derivation, proposes some alternative choices of parameters in the methods and categorizes them.

TL;DR: An application of reduced basis method for Stokes equations in domains with affine parametric dependence is presented, ideally suited for the repeated and rapid evaluations required in the context of parameter estimation, design, optimization, and real-time control.

TL;DR: A new robust technique for solving stochastic partial differential equations that generalizes the classical spectral decomposition, namely the Karhunen-Loeve expansion, and enables the construction of a relevant reduced basis of deterministic functions which can be efficiently reused for subsequent resolutions.

TL;DR: A systematic approach to approximate the Pareto optimal front (POF) by a response surface approximation is presented, and the approximated POF can help visualize and quantify trade-offs among objectives to select compromise designs.

TL;DR: In this paper, a model reduction approach for periodic heterogeneous media, which combines the multiple scale asymptotic (MSA) expansion method with the transformation field analysis (TFA) to reduce the computational cost of a direct homogenization approach without significantly compromising on solution accuracy, is presented.

TL;DR: In this paper, the authors describe a method for exploiting the typically small deformations experienced by arteries during the cardiac cycle while retaining essential features of the complex nonlinear, anisotropic behavior of the wall relative to unloaded configurations.

TL;DR: A stabilized finite element approximation for the incompressible Navier–Stokes equations based on the subgrid-scale concept is analyzed and the properties of the discrete formulation that results allowing the sub grid-scales to depend on time are explored.

TL;DR: In this article, a divergence-free displacement field is computed from a scalar potential by means of a "stream-function" formulation such that the displacement field can be automatically locking-free in the presence of the incompressibility constraint.

TL;DR: In this paper, the extended finite element method (XFEM) is used for a discrete crack simulation of concrete using an adaptive crack growth algorithm, and different criteria for predicting the direction of the extension of a cohesive crack are investigated in the context of the XFEM.

TL;DR: Numerical results show that the formulation that incorporates the law of the wall yields an improvement over the original method, which presents a robust technique for flows of industrial interest.

TL;DR: The state-of-the-art for the classical residual-based SUPG/PSPG method is described and recent symmetric stabilization techniques which avoid some drawbacks of the classical method are discussed.

TL;DR: In this article, an algorithm is developed for the efficient characterization of a lower dimensional manifold occupied by the solution to a stochastic partial differential equation (SPDE) in the Hilbert space spanned by Wiener chaos.

TL;DR: Six methods that can deal with the information transfer between non-matching meshes in fluid–structure interaction computations are compared for different criteria and two methods based on radial basis functions are favoured over the other methods because of their high accuracy and efficiency.

TL;DR: In this paper, a multiscale methodology has been developed for modeling mechanical behavior of collagen fiber networks, addressing scale separation between the macroscopic, tissue-level scale and the microscopic, fiber-scale.

TL;DR: In this article, the authors extended recent advances in the topology optimization of fluid flows to the design of periodic, porous material microstructures, where the goal is to determine the layout of solid and fluid phases that will yield maximum permeability and prescribed flow symmetries in bulk material.

TL;DR: In this paper, the void phase is defined to be an incompressible hydrostatic fluid, which can transfer pressure loads through the fluid without any need for special load surface parametrizations.

TL;DR: In this paper, the proper orthogonal decomposition (POD) approach is applied to the case of multiple parameters in the context of a class of reduced-order models.

TL;DR: In this article, a tensor-based finite element formulation is presented to describe the mathematical model of a shell in a natural and simple way by using curvilinear coordinates, and a family of high-order elements with Lagrangian interpolations is used to avoid membrane and shear locking, and no mixed interpolations are employed.

TL;DR: In this article, a global energy-based method is proposed for the determination of the crack propagation length as well as for the crack propagating direction, which is formulated within an X-FEM-based analysis model leading to a variational formulation in terms of displacements, crack lengths and crack angles Both cohesive and cohesionless cracks are considered.

TL;DR: In this article, an implicit moving mesh algorithm for the study of the propagation of plane-strain hydraulic fracture in an impermeable medium is presented, where the fluid front is allowed to lag behind the fracture tip.

TL;DR: In this paper, a new conceptually simple scheme was implemented in an updated Lagrange formulation for large deformation finite element (FE) simulations of anisotropic material, which showed quadratic convergence for arbitrary degrees of deformation and arbitrary deformations with strain increments over 100%.