Influence of Scour Protection on the Vertical Bearing Behaviour of Monopiles in Sand

Extensive studies have been performed on the effectiveness of scour protection against scour erosion progression. But there is little research to date evaluating the effect of scour protection on vertical resistance behaviour of monopile foundations. This paper investigates the influence of scour protection on the vertical loading behaviour of...

Scour Effect on the Lateral Bearing Behaviour of Monopiles Considering Different Slenderness Ratios

Scour leads to the loss of soil around monopile foundations for offshore wind turbines, which affects their structural safety. In this paper, the effect of scour on the lateral behaviour of monopiles was extensively investigated using finite element analysis, and calibration and comparison were undertaken using centrifuge tests. Piles with three...

Point Forces and Their Alternatives in Cell-Based Models for Skin Contraction in Two Dimensions

Deep tissue injury is often followed by contraction of the scar tissue. This contraction occurs as a result of pulling forces that are exerted by fibroblasts (skin cells). We consider a cell-based approach to simulate the contraction behavior of the skin. Since the cells are much smaller than the wound region, we model cellular forces by...

Bounds for decoupled design and analysis discretizations in topology optimization

Topology optimization formulations using multiple design variables per finite element have been proposed to improve the design resolution. This paper discusses the relation between the number of design variables per element and the order of the elements used for analysis. We derive that beyond a maximum number of design variables, certain sets...

Automated computational modelling for complicated partial differential equations

In engineering, physical phenomena are often described mathematically by partial differential equations (PDEs), and a commonly used method to solve these equations is the finite element method (FEM). Implementing a solver based on this method for a given PDE in a computer program written in source code can be tedious, time consuming and error...

Automated Solution of Partial Differential Equations with Discontinuities using the Partition of Unity Method

Although computers were invented to automate tedious and error-prone tasks, computer programming is a tedious and error-prone task itself. This is a well-known paradox in the field of computational mathematical modelling. Recently, automatic code generation has been proposed to solve this paradox. In this approach, a required code to model...

A stress-based gradient-enhanced damage model

One of the shortcomings of nonlocal damage models with a constant length scale parameter is the wrong prediction of damage initiation and propagation in correspondence of a strongly inhomogeneous strain field. This unphysical behavior can be corrected by considering an evolving length scale which is made a function of the stress state. Giry,...

Discontinuous Galerkin methods with solenoidal elements for the Stokes problem

The essential difficulty in the numerical solution of the incompressible Navier-Stokes (NS) equations is the coupling between the pressure and the velocity. The coupling enforces a constraint on the relation between the pressure and the velocity space. This constraint can be studied using a simplified form of the NS equations, viz. the Stokes...

Analytical and Numerical Developments in Optimal Shape Design for Aerospace: An overview

Analysis of finite element methods for coupled Hydro-Mechanical problems

This work is concerned with the analysis of a non-stationary Hydro-Mechanical problem. The well-posedness of the continuous, time semi-discretized and fully discretized problems is addressed. An a posteriori error analysis is performed, leading to a family of space-time error indicators. The reliability of this family, i.e. a global upper bound...

A parallel finite element method for two-phase flows

A parallel finite element model for incompressible laminar two-phase flows is presented. A two-fluid model, describing the laminar non-equilibrium flow of two incompressible phases, is discretized by means of a properly designed Streamline Upwind Petrov-Galerkin (SUPG) finite element procedure. Such a procedure is consistent with a continuous...

Krylov-Subspace Preconditioners for Discontinuous Galerkin Finite Element Methods

Standard (conforming) finite element approximations of convection-dominated convection-diffusion problems often exhibit poor stability properties that manifest themselves as non-physical oscillations polluting the numerical solution. Various techniques have been proposed for the stabilisation of finite element methods (FEMs) for convection...

Space-Time Discontinuous Galerkin Method for the Compressible Navier-Stokes

An overview is given of a space-time discontinuous Galerkin finite element method for the compressible Navier-Stokes equations. This method is well suited for problems with moving (free) boundaries which require the use of deforming elements. In addition, due to the local discretization, the space-time discontinuous Galerkin method is well...

Flooding and drying in discontinuous Galerkin discretizations of shallow water equations

Flooding and drying in space or space-time discontinuous Galerkin (DG) discretizations provides an accurate and efficient numerical scheme. Moreover, the space-time DG method is particularly suitable for moving or deforming meshes. The shallow water equations, which can exhibit flooding and drying due to the movement of water front, are...

A CAD-system for the design of stiffened panels in wing box structures

In this paper the CAD system DESTIP is described. DESTIP is developed at the NLR for designing compression panels in wing box structures. Application of the system yields optimal panels in the sense that they meet all the requirements imposed by the designer and have minimum weight per unit width. Weight reductions ranging from 0 to 10% have...

Methoden voor het verbeteren van dynamische modellen van constructies

A survey of computational methods to improve dynamic analytical models described in the literature is made. Both the matrix methods and the optimal correction method of the dynamic model using the measured modes are discussed.