43 research outputs found
SOLID-SHELL FINITE ELEMENT MODELS FOR EXPLICIT SIMULATIONS OF CRACK PROPAGATION IN THIN STRUCTURES
Crack propagation in thin shell structures due to cutting is conveniently simulated
using explicit finite element approaches, in view of the high nonlinearity of the problem. Solidshell
elements are usually preferred for the discretization in the presence of complex material
behavior and degradation phenomena such as delamination, since they allow for a correct
representation of the thickness geometry. However, in solid-shell elements the small thickness
leads to a very high maximum eigenfrequency, which imply very small stable time-steps. A new
selective mass scaling technique is proposed to increase the time-step size without affecting
accuracy. New ”directional” cohesive interface elements are used in conjunction with selective
mass scaling to account for the interaction with a sharp blade in cutting processes of thin ductile
shells
Modeling and simulation of sintering process across scales
Sintering, as a thermal process at elevated temperature below the melting
point, is widely used to bond contacting particles into engineering products
such as ceramics, metals, polymers, and cemented carbides. Modelling and
simulation as important complement to experiments are essential for
understanding the sintering mechanisms and for the optimization and design of
sintering process. We share in this article a state-to-the-art review on the
major methods and models for the simulation of sintering process at various
length scales. It starts with molecular dynamics simulations deciphering
atomistic diffusion process, and then moves to microstructure-level approaches
such as discrete element method, Monte--Carlo method, and phase-field models,
which can reveal subtle mechanisms like grain coalescence, grain rotation,
densification, grain coarsening, etc. Phenomenological/empirical models on the
macroscopic scales for estimating densification, porosity and average grain
size are also summarized. The features, merits, drawbacks, and applicability of
these models and simulation technologies are expounded. In particular, the
latest progress on the modelling and simulation of selective and direct-metal
laser sintering based additive manufacturing is also reviewed. Finally, a
summary and concluding remarks on the challenges and opportunities are given
for the modelling and simulations of sintering process.Comment: 45 pages, 38 figure
MS FT-2-2 7 Orthogonal polynomials and quadrature: Theory, computation, and applications
Quadrature rules find many applications in science and engineering. Their analysis is a classical area of applied mathematics and continues to attract considerable attention. This seminar brings together speakers with expertise in a large variety of quadrature rules. It is the aim of the seminar to provide an overview of recent developments in the analysis of quadrature rules. The computation of error estimates and novel applications also are described
Industrial Applications: New Solutions for the New Era
This book reprints articles from the Special Issue "Industrial Applications: New Solutions for the New Age" published online in the open-access journal Machines (ISSN 2075-1702). This book consists of twelve published articles. This special edition belongs to the "Mechatronic and Intelligent Machines" section
Convective and segregative mechanisms in vibrofluidised granular systems
Granular materials display a host of fascinating behaviours both remarkably similar to and strikingly different from those exhibited by classical solids, liquids and gases. Due to the ubiquity of granular materials, and their far-reaching importance in multitudinous natural and industrial processes, an understanding of their dynamics is of the utmost importance to modern society. In this thesis, we analyse in detail two phenomena, one from each of the above categories: granular convection, a behaviour directly analogous to the Rayleigh-Benard cells observable in classical fluids, and granular segregation, a phenomenon without parallel in classical, molecular physics, yet which is known to greatly impact various physical and industrial systems. Through this analysis, conducted using a combination of the experimental positron emission particle tracking technique and discrete particle method simulations, we aim to improve our knowledge of these processes on a fundamental level, gaining insight into the factors which may influence them, and hence how they may be effectively controlled, augmented or eliminated