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.

Deformation and Damage of Thermally Bonded Nonwoven Networks

Abstract: Nonwovens, composed of randomly-oriented polymer-based fibres, possess unique properties, with features common to paper, plastic and textile materials. From various types of bonding technologies used in the nonwovens industry. This chapter focuses on thermal bonding and respective fabrics as it is one of the most widely used techniques. Understanding a mechanical behaviour of polymer-based nonwoven materials that includes large-strain deformation and damage can help to evaluate a response of nonwoven fibrous networks to various loading conditions. The main deformation and damage mechanisms are analysed by means of experimental assessment of fabrics in tension alongside damage evolution based on progressive failure of fibres. Finite-element simulation strategies to gain insight into their behaviour and to achieve quantitative exploration of a design space for these materials are also discussed in this chapter.

Mesoscale damage behavior and meso-macroscale correlation of low-cycle fatigue in Z2CND18.12N austenitic stainless steel

Abstract: A low-cycle-fatigue damage behavior in Z2CND18.12N austenitic stainless steel is mainly studied at mesoscale, focusing on the correlation with that at macroscale. The variations of local misorientation in electron backscatter diffraction, ΔML, first increased with cyclic loading, then decreased to the minimum, and finally increased significantly, with <110> and <111> orientations having higher values than <100>. This evolution was positively correlated with the fraction of multiple slips and maximum von Mises stress, and negatively with the plastic-strain amplitude at macroscale in experiments and mesoscale in crystal-plasticity finite-element modeling. A ΔML model is proposed based on the dislocation evolution and slip mode.

The influence of the microstructure on the effective properties of duplex-type materials under purely thermal loading

Abstract: An analysis is carried out to study the influence of the microstructure on the effective thermomechanical properties of cylindrical specimens of ferritic-austenitic duplex steels under the conditions of purely thermal cyclic loading in the temperature interval ranging from 20 °C to 900 °C. Three different representations for the microstructure of duplex steels with extreme matrix-inclusion topology are realised: a two-zone model and models with a random distribution of the inclusion phase at two different characteristic length scales. The first approach allows to gain some analytical estimates for the coefficients of thermal expansion and for the critical temperature at which the behaviour departs from a thermoelastic one. An additional theoretical analysis based on the Eshelby approach deals with the influence of the morphology of grains/clusters of the inclusions phase on the effective properties. Using an additional topological parameter (number of clusters) together with other parameters characterising the phase distribution makes possible the comparison of results obtained from the different geometries. Conditions for the microstructure-related transition between different types of response of specimens to the thermal cyclic loading, namely ratchetting and plastic shakedown, are discussed.

Thermo-mechanical characteristics of indium micro-joint under various low-temperature excursions

Abstract: Properties of an indium joint used as interconnection in pixelated detector systems play a key role in determining their functionality since each indium joint represents a pixel, which defines a resolution limit of the sensor. Additionally, such detectors are required to operate at cryogenic temperatures. Thus, the thermal conditions that indium joints in service life can be harsh, for example, changing from room temperature to liquid-nitrogen temperature. In this paper, thermo-mechanical characteristics of indium joints under various low-temperature excursions were investigated numerically. This approach provides a useful tool for the better understanding of a thermo-mechanical response of such system to various in-service conditions as well as their reliable performance.

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.