Multiscale Modelling and Optimisation of Materials and Structures. Tadeusz Burczynski. Читать онлайн. Newlib. NEWLIB.NET

Автор: Tadeusz Burczynski
Издательство: John Wiley & Sons Limited
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Жанр произведения: Техническая литература
Год издания: 0
isbn: 9781118536452
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an approach [3].

      1.1.3 Prospective Applications of the Multiscale Modelling

      In recent years, a gradual paradigm shift has been taking place in the selection of materials to suit particular engineering requirements, especially in high‐performance applications. The empirical approach adopted by materials scientists and engineers in choosing materials parameters from a database is being replaced by design based on the DMR concept. Features that span across a large spectrum of length scales are altered and controlled to achieve the desired properties and performance at the macroscale. Research efforts, in this aspect, include the development of engineering materials by changing the composition, morphology, and topology of their constituents at the microscopic/mesoscopic level. The objective of this book is to show multiscale methods and their applications in computational materials design. From one side, we present computational multiscale material modelling based on the bottom‐up/top‐down, one‐way coupled description of the material structure in different representative scales. On the other side, our intention is to show possibilities of a combination of multiscale methods with optimization techniques.

      Solution of optimization problems in multiscale modelling allows finding structures with better performance or strength in one scale with respect to design variables in another scale. In this case, the typical situation is to find a vector of material or geometrical parameters on the micro‐level, which minimizes an objective function dependent on state fields on a macro‐level of the structure.

      A special case of optimization problems associated with the multiscale approach is the optimization of atomic clusters for the minimization of the system's potential energy. This case has an important consequence, especially in the design of new 2D nanomaterials and nanostructures.

      The identification problem is formulated as the evaluation of some geometrical or material parameters of structures in one scale having measured information in another scale. The important case of identification in multiscale modelling is to find material properties, the shape of the inclusions/fibres or voids in the microstructure having measurements of state fields made on the macro‐object. The identification problem is formulated and considered as a special optimization task.

      The aspects of multiscale modelling mentioned previously have already been discussed in numerous publications, including several books [4, 12, 13, 15]. However, multiscale modelling still remains a difficult task, and its valid and reliable application is quite difficult. Moreover, the lack of an unambiguous definition leads to misunderstandings and mistakes. The book supplies some practical information concerning the development and application of multiscale material models, in particular in combination with optimization techniques.

      As mentioned, the book is divided into three main sections. The first section is composed of Chapters 2 and 3, and it is focused on discussion of phenomena occurring in materials in processing and on models used to describe these phenomena. Such phenomena as recrystallization, phase transformations, cracking, fatigue, and creep are discussed very briefly. The modelling methods are divided into two groups. The first includes computational methods for continuum such as FEM, XFEM, and BEM. Discrete methods describing microscale and nanoscale phenomena include MS as well as MD, CA, and MC approaches. Computational homogenization methods, which are used in the coupled multiscale models, are also discussed in this part of the book. Basic principles of methods of optimization are also described in this part of the book, with a particular emphasis on the methods inspired by nature.

      The second section of the book is composed of Chapters 4 and 5 and focuses on DMR. Case studies based on DMR are presented. Applications of methods described in Chapters 2 and 3 to modelling various processes and phenomena are shown.

      The third section of the book is connected with applications of multiscale optimization methods. Such issues as optimization of atomic clusters, material parameters optimization, shape optimization, and topological optimization are discussed. The problem of identification in multiscale modelling is also presented.

      Computer implementation issues for multiscale models are recapitulated in the book. Implementation of selected algorithms concerning visualization as well as scales coupling with use of commercial software are described in Chapter 7. The part will highlight the possibilities of increasing the computational efficiency, which is especially important when optimization based on a direct problem model of multiscale nature is considered.

      1 1 Allix, O. (2006). Multiscale strategy for solving industrial problems. In: III European Conference on Computational Mechanics (ed. C.A. Motasoares, J.A.C. Martins, H.C. Rodrigues, et al.), 107–126. Dordrecht: Springer.

      2 2 De Borst, R. (2008). Challenges in computational materials science, multiple scales, multi‐physics and evolving discontinuities. Computational Material Science 43: 1–15.

      3 3 Feyel, F. (1999). Multiscale FE2 elastoviscoplastic analysis of composite structures. Computational Materials Science 16: 344–354.

      4 4 Fish, J. (2014). Practical Multiscaling. Wiley.

      5 5 Horstemeyer, M.F. and Wang, P. (2003). Cradle‐to‐grave simulation‐based design incorporating multiscale microstructure‐property modeling: reinvigorating design with science. Journal of Computer‐Aided Materials Design 10: 13–34.

      6 6 Kilner, J.A., Skinner, S.J., Irvine, S.J.C., and Edwards, P.P. (ed.) (2012). Functional Materials for Sustainable Energy Applications. Oxford, Cambridge, Philadelphia, New Delhi: Woodhead Publishing Ltd.

      7 7 Madej,