Vadim V. Silberschmidt

Bio: Vadim V. Silberschmidt is an academic researcher from Loughborough University. The author has contributed to research in topics: Machining & Materials science. The author has an hindex of 44, co-authored 543 publications receiving 8619 citations. Previous affiliations of Vadim V. Silberschmidt include University of Rhode Island & Universities UK.

Dynamic damage in FRPs: From low to high velocity

Abstract: Fibre-reinforced polymer composites (FRPs) are extensively used in protective elements and structures exposed to a wide range of impact loading. The range of application is comprehensive, with impact velocities (and, consequently, impact energies) ranging from low to high levels. As widely reported, damage mechanisms in FRPs are observed to change significantly with the nature of impact, and hence need better understanding and assessment. In this chapter, impact events are studied in some detail using a numerical approach in analysis of various experimental data. Finite-element models of FRPs, once accurately developed and validated, allow elucidation of various deformation and damage mechanisms underpinning composite failure across impact-velocity envelopes. In this regard, results are discussed that were obtained from the authors' work on air blast on FRPs and ballistic impact on woven composites using a numerically accurate and computationally efficient modelling framework.

Effect of Microstructure: Multi-scale Modelling

Abstract: A study of a structure of any real material would vividly demonstrate the presence of several hierarchical levels — from atoms to microscopic features to the macroscopic scale of a specimen/component/structure. Depending on the type of material and its microstructure, several scales — six for highly heterogeneous cases such as composite structures (Beaumont et al., 2008) and bones (Rho et al., 1998) — can be introduced. These scales can cover in various materials the range of lengths from nanometres to centimetres or metres. An obvious reason for introduction of any additional scale into consideration is specificity of its structure and/or of the character of realisation of deformation and failure processes at the corresponding scale.

Micro CT analysis of dynamic damage in laminates: impact vs. blast loading

Abstract: Dynamic loading is often an unavoidable condition in various applications of carbon-fibre-reinforced polymers and can cause various modes of damage. Realisation of dynamic damage in composites can differ significantly from that under quasi-static loading conditions. A comprehensive study of damage in composites caused by a wide variety of impact and blast loading is currently lacking. The work presents a detailed analysis of damage in specimens of a 2×2 twill weave T300 carbon-fibre/epoxy composite subjected to ballistic loading with both steel and ice projectiles (with energies from 95 J to 865 J at 70-90 m/s and 300-500 m/s, respectively) and air blast (with incident pressures of 0.4 MPa, 0.6 MPa and 0.8 MPa and wave speeds between 650 m/s and 950 m/s). The resultant damage was analysed in-depth based on detailed volumetric data obtained with high-resolution X-ray micro computed tomography.

Fast parallel algorithms for short-range molecular dynamics

Abstract: Three parallel algorithms for classical molecular dynamics are presented. The first assigns each processor a fixed subset of atoms; the second assigns each a fixed subset of inter-atomic forces to compute; the third assigns each a fixed spatial region. The algorithms are suitable for molecular dynamics models which can be difficult to parallelize efficiently—those with short-range forces where the neighbors of each atom change rapidly. They can be implemented on any distributed-memory parallel machine which allows for message-passing of data between independently executing processors. The algorithms are tested on a standard Lennard-Jones benchmark problem for system sizes ranging from 500 to 100,000,000 atoms on several parallel supercomputers--the nCUBE 2, Intel iPSC/860 and Paragon, and Cray T3D. Comparing the results to the fastest reported vectorized Cray Y-MP and C90 algorithm shows that the current generation of parallel machines is competitive with conventional vector supercomputers even for small problems. For large problems, the spatial algorithm achieves parallel efficiencies of 90% and a 1840-node Intel Paragon performs up to 165 faster than a single Cray C9O processor. Trade-offs between the three algorithms and guidelines for adapting them to more complex molecular dynamics simulations are also discussed.

The Design and Analysis of Experiments

Abstract: THE DESIGN AND ANALYSIS OF EXPERIMENTS. By Oscar Kempthorne. New York, John Wiley and Sons, Inc., 1952. 631 pp. $8.50. This book by a teacher of statistics (as well as a consultant for \"experimenters\") is a comprehensive study of the philosophical background for the statistical design of experiment. It is necessary to have some facility with algebraic notation and manipulation to be able to use the volume intelligently. The problems are presented from the theoretical point of view, without such practical examples as would be helpful for those not acquainted with mathematics. The mathematical justification for the techniques is given. As a somewhat advanced treatment of the design and analysis of experiments, this volume will be interesting and helpful for many who approach statistics theoretically as well as practically. With emphasis on the \"why,\" and with description given broadly, the author relates the subject matter to the general theory of statistics and to the general problem of experimental inference. MARGARET J. ROBERTSON

American Society for Testing and Materials

Abstract: The American Society for Testing and Materials (ASTM) is an independent organization devoted to the development of standards.

Effect of Temperature

Abstract: A positive temperature coefficient is the term which has been used to indicate that an increase in solubility occurs as the temperature is raised, whereas a negative coefficient indicates a decrease in solubility with rise in temperature.