In this book, the underlying damage mechanisms of materials used under extreme conditions are explored using computer simulation and modelling methods, presenting important information to predict the lifetime of related facilities. The scope of this book embraces numerical work on material responses to extreme conditions, such as high-speed impact or loading, neutron or ion irradiation, and high-pressure and/or high-temperature environments. Related simulation results based on the first principle method, molecular dynamics, and finite element methods are reported. Results of various topics have been reported by papers collected in this book, for example, including fitting a better empirical potential, diffusion of atoms on surface, corrosion, interaction between different defects, elastic constants calculations, effect of hot press forming on collision toughness and energy distribution, and influence of radiation defects on the thermo-mechanical properties of UO2. Furthermore, a review about the experiments and models for the effect of strain rate on NiTi shape memory alloys (SMAs) has also been included in this book. These new results present new knowledge for understanding the damage mechanisms of materials under extreme conditions, which would be useful not only for researchers in these fields but also for new readers to learn about basic concepts and current research progress to better understand the response of materials under extreme conditions.

In this reprint, the underlying damage mechanisms of materials used under extreme conditions are explored using computer simulation and modelling methods, presenting important information to predict the lifetime of related facilities. The scope of this reprint embraces numerical work on material responses to extreme conditions, such as high-speed impact or loading, neutron or ion irradiation, and high-pressure and/or high-temperature environments. Related simulation results based on the first principle method, molecular dynamics, and finite element methods are reported. Results of various topics have been reported by papers collected in this book, for example, including fitting a better empirical potential, diffusion of atoms on surface, corrosion, interaction between different defects, elastic constants calculations, effect of hot press forming on collision toughness and energy distribution, and influence of radiation defects on the thermo-mechanical properties of UO2. Furthermore, a review about the experiments and models for the effect of strain rate on NiTi shape memory alloys (SMAs) has also been included in this reprint. These new results present new knowledge for understanding the damage mechanisms of materials under extreme conditions, which would be useful not only for researchers in these fields but also for new readers to learn about basic concepts and current research progress to better understand the response of materials under extreme conditions.

The book presents twelve state of the art contributions in the field of numerical modeling of materials subjected to large strain, high strain rates, large pressure and high stress triaxialities, organized into two sections. The first part is focused on high strain rate-high pressures such as those occurring in impact dynamics and shock compression related phenomena, dealing with material response identification, advanced modeling incorporating microstructure and damage, stress waves propagation in solids and structures response under impact. The latter part is focused on large strain-low strain rates applications such as those occurring in technological material processing, dealing with microstructure and texture evolution, material response at elevated temperatures, structural behavior under large strain and multi axial state of stress.

The study of materials properties under extreme conditions has made considerable progress over the past decade due to both improvements in experimental techniques and advanced modeling methods. The availability of accurate models is crucial in order to analyze experimental results obtained in extreme conditions of pressure and temperature where experimental data can be scarce. Among theoretical models, ab initio simulations are playing an increasingly important role due to their ability to predict materials properties without the need for any experimental input. Ab initio simulations also allow for an exploration of materials properties in conditions that are unachievable using controlled experiments--such as e.g. the conditions prevailing in the core of large planets. In that limit, they constitute the only quantitative model of condensed matter available today. In this article, we review the current status of ab initio simulations and discuss examples of recent applications in which numerical simulations have provided an essential complement to experimental data.

Heterogeneous materials under dynamic loading exhibit dramatic transformations resulting in self-organization and in situ microstructural changes due to the complex interaction of nonlinearity, dispersion, different mechanisms of softening, and fracture. We use numerical simulations to explain the diverse mechanisms of deformation, localization and in situ patterning exhibited by these materials and compare them to experimental results and phenomenological models. In Chapters 2 and 3 we study dissipative Al-W laminates with unit cells 1, 2 and 4 mm under high velocity impact loading of different durations. Depending on the duration of the loading pulse, a qualitatively new solitarylike wave, a train of such waves or a quasistationary shockwave is formed in these dissipative laminates. A phenomenological model based on the Korteweg-de Vries equation is formulated introducing important space/time scaling for solitary and shock waves depending on materials properties. In Chapter 4, Thick-Walled Cylinder experiments were conducted with highly heterogeneous porous mixtures of Al and W granular materials. Results were compared with numerical simulations to explore the effects of grain size and porosity on the mechanism of cavity instability. Numerical simulations demonstrated that a shear band like phenomena occurs along weak paths created by softer Al particles. The samples with initial porosity, delayed this mechanism of instability. Samples with grain sizes 400 and 100 micron demonstrated loss of cylindrical symmetry during collapse and sample with grain size 40 micron collapsed with mostly preserved cylindrical symmetry. This was consistent with experimental observation of cavity collapse in mixtures with 40 and 1 micron W particles. In Chapter 5, explosively driven Thick-Walled Cylinder experiments were conducted with samples of 4340 steel having variable microstructures achieved through heat treatment. It was observed experimentally that the change in the initial microstructure resulted in completely different dynamic behavior and self-organization of shear bands/cracks. The heat treated sample, catastrophically failed due the formation and interaction of shear bands developing into cracks. Numerical simulations are compared to the experimental results. It was shown that the inclusion of artificial defects is necessary to reproduce self-organized pattern of shear bands and cracks observed in experiments.

Nowadays, it is quite easy to see various applications of fibrous composites, functionally graded materials, laminated composite, nano-structured reinforcement, morphing composites, in many engineering fields, such as aerospace, mechanical, naval and civil engineering. The increase in the use of composite structures in different engineering practices justify the present international meeting where researches from every part of the globe can share and discuss the recent advancements regarding the use of standard structural components within advanced applications such as buckling, vibrations, repair, reinforcements, concrete, composite laminated materials and more recent metamaterials. For this reason, the establishment of this 19th edition of International Conference on Composite Structures has appeared appropriate to continue what has been begun during the previous editions. ICCS wants to be an occasion for many researchers from each part of the globe to meet and discuss about the recent advancements regarding the use of composite structures, sandwich panels, nanotechnology, bio-composites, delamination and fracture, experimental methods, manufacturing and other countless topics that have filled many sessions during this conference. As a proof of this event, which has taken place in Porto (Portugal), selected plenary and keynote lectures have been collected in the present book.

High-pressure materials research has been revolutionized in the past few years due to technological breakthroughs in the diamond anvil cell (DAC), shock wave compression and molecular dynamic simulation (MD) methods. The application of high pressure, especially together with high temperature, has revealed exciting modifications of physical and chemical properties even in the simplest molecular materials.Besides the fundamental importance of these studies to understand the composition and the dynamics of heart and planets' interior, new materials possessing peculiar characteristics of hardness and composition have been synthesized at very high pressure, while unexpected chemical reactions of simple molecules to polymers and amorphous compounds have been found at milder conditions.The variety of the phenomena observed in these extreme conditions and of the materials involved provides a common ground bridging scientific communities with different cultural and experimental backgrounds. This monograph will provide a timely opportunity to report on recent progress in the field.