Designing engineering components that make optimal use of materials requires consideration of the nonlinear characteristics associated with both manufacturing and working environments. The modeling of these characteristics can only be done through numerical formulation and simulation, and this requires an understanding of both the theoretical background and associated computer solution techniques. By presenting both nonlinear continuum analysis and associated finite element techniques under one roof, Bonet and Wood provide, in this edition of this successful text, a complete, clear, and unified treatment of these important subjects. New chapters dealing with hyperelastic plastic behavior are included, and the authors have thoroughly updated the FLagSHyP program, freely accessible at www.flagshyp.com. Worked examples and exercises complete each chapter, making the text an essential resource for postgraduates studying nonlinear continuum mechanics. It is also ideal for those in industry requiring an appreciation of the way in which their computer simulation programs work.

https://cdn.preterhuman.net/texts/science_and_technology/physics/Mechanics/Nonlinear%20Continuum%20Mechanics%20For%20Finite%20Element%20Analysis%20-%20Bonet,%20Wood.pdf

Nonlinear Continuum Mechanics for Finite Element Analysis

This chapter introduces the finite element method (FEM) as a tool for solution of classical electromagnetic problems. Although we discuss the main points in the application of the finite element method to electromagnetic design, including formulation and implementation, those who seek deeper understanding of the finite element method should consult some of the works listed in the bibliography section.

Introduction to the Finite Element Method

A phase-field description of dynamic brittle fracture

The finite element analysis of delamination in laminated composites is addressed using interface elements and an interface damage law. The principles of linear elastic fracture mechanics are indirectly used by equating, in the case of single-mode delamination, the area underneath the traction/relative displacement curve to the critical energy release rate of the mode under examination. For mixed-mode delamination an interaction model is used which can fulfil various fracture criteria proposed in the literature. It is then shown that the model can be recast in the framework of a more general damage mechanics theory. Numerical results are presented for the analyses of a double cantilever beam specimen and for a problem involving multiple delamination for which comparisons are made with experimental results. Issues related with the numerical solution of the non-linear problem of the delamination are discussed, such as the influence of the interface strength on the convergence properties and the final results, the optimal choice of the iterative matrix in the predictor and the number of integration points in the interface elements. Copyright © 2001 John Wiley & Sons, Ltd.

Finite element interface models for the delamination analysis of laminated composites: mechanical and computational issues

Effective properties of composite materials with periodic microstructure : a computational approach

The use of partition of unity based discontinuous finite element formulations for the simulation of crack propagation with implicit simulations is now well established. However, in explicit simulations the accuracy is still a point of concern. Some outstanding issues will be addressed in this paper.

An evaluation of the accuracy of discontinuous finite elements in explicit dynamic calculations

Efficient modelling of ceramic sintering processes: Application to bilayers and membranes

In the context of additive manufacturing (AM) and 3D Printing, vat photopolymerization is an established technique in which photopolymer is selectively solidified to form a near-net-shape part. Photopolymerization-based AM is increasingly being adopted by the high-tech industry, but the technology still faces several challenges in terms of consistency in product quality, understanding of the UV curing process, in-situ process monitoring, and real-time closed-loop control. This paper aims to demonstrate the potential of model-based control of the UV curing process. The curing process is modelled and anticipatively controlled with an optimal control law for nonlinear systems, derived via a sequential linearization strategy. The potential of this approach is proven by means of both simulations that illustrate a one-dimensional spatial optimal tracking problem and experiments that validate a zero-dimensional controlled system.

Real-Time Nonlinear Tracking Control of Photopolymerization for Additive Manufacturing

The added benefit of Additive Manufacturing (AM) is undeniable in terms of increased design freedom, product customization and small batch production. These benefits come with the challenges of part distortion, internal stresses and process dependent material properties. To improve print quality and increase yield in the printing process, accurate prediction of part deformations, residual stresses, material properties, temperature distribution and history as a function of the printing parameters is desired. The aim for this contribution is to develop a generic Multi-physics AM process simulation framework based on element addition in a Finite Element Method context to simulate the AM process with Fused Deposition Modeling (FDM) as the main AM process. The proposed generic simulation framework is based on a coupled transient thermomechanical model with a timestepping solution procedure. In contrast to the commonly used quiet and dead/alive element activation method [1] this model utilizes a novel element addition strategy. This strategy takes into account the kinematics and initial conditions of the newly added material to model the increasing simulation domain characteristic for AM processes. For the development of this framework small strains are assumed and simple material models are being utilized. The same GCode machine instructions, as typically used in 3D printers, are used as an input to determine the trajectory for the addition of voxel elements such that no prior knowledge of the intended geometry is required. This is schematically shown in Figure 1. In allow for the application of convection and radiation boundary conditions on the continuously changing simulation domain, a boundary detection algorithm is implemented. Figure 1: Schematic representation of the GCode implementation to the simulation framework, that allows to use the same input as being used in the printing process

Consistent transient thermomechanical process modeling for additive manufacturing

To model the engineering performance of components made of polyvinylidene fluoride (PVDF), the 3D elasto-viscoplastic Eindhoven glassy polymer (EGP) model is extended to describe the rate-dependent behavior of PVDF. Careful analysis of the intrinsic behavior of PVDF revealed that the postyield compressive response shows a strain rate-dependence that evolves with increasing deformation. The extension of the constitutive model captures the deformation-dependent evolution of the activation volume and the rate-factor, which describes the driving stress. Given the significant temperature-dependent behavior, the model has been characterized for different temperatures (23, 55 and 75 °C). The accuracy of the model has been validated by means of tension and creep experiments at these temperatures. The constitutive model is implemented in finite element simulations and the results are compared with the experiments. It is shown that the proposed model allows for an accurate prediction of the short- and long-term rate-dependent behavior of PVDF. 

https://onlinelibrary.wiley.com/doi/pdfdirect/10.1002/pol.20220729

Joris J.C. Remmers

Papers

An evaluation of the accuracy of discontinuous finite elements in explicit dynamic calculations

Efficient modelling of ceramic sintering processes: Application to bilayers and membranes

Real-Time Nonlinear Tracking Control of Photopolymerization for Additive Manufacturing

Consistent transient thermomechanical process modeling for additive manufacturing

An elasto‐viscoplastic constitutive model for the rate‐dependent behavior of polyvinylidene fluoride