Lecture Notes on Composite Materials: Current Topics and Achievements

ISBN-13: 9789048179817 / Angielski / Miękka / 2010 / 237 str.

Tomasz Sadowski; Rene De Borst

Opis

Composite materials are heterogeneous by nature, and are intended to be, since only the combination of different constituent materials can give them the desired combination of low weight, stiffness and strength. At present, the knowledge has advanced to a level that materials can be tailored to exhibit certain, required properties. At the same time, the fact that these materials are composed of various, sometimes very different constituents, make their mechanical behaviour complex. This observation holds with respect to the deformation behaviour, but especially with respect to the failure behaviour, where complicated and unconventional failure modes have been observed. It is a challenge to develop predictive methods that can capture this complex mechanical behaviour, either using analytical tools, or using numerical me- ods, the ?nite element method being the most widespread among the latter. In this respect, developments have gone fast over the past decade. Indeed, we have seen a paradigm shift in computational approaches to (composite) ma- rial behaviour. Where only a decade ago it was still customary to carry out analyses of deformation and failure at a macroscopic level of observation only - one may call this a phenomenological approach - nowadays this approach is being progressively replaced by multiscale methods. In such methods it is r- ognized a priori that the overall behaviour is highly dependent on local details and ?aws.

Spis treści

Holm Altenbach Analysis of Homogeneous and Non-homogeneous Plates 1 Classification of Structural Models 1.1 Introductional Remarks 1.2 Two-dimensional Structures—Definition, Applications, Some Basic References 1.3 Formulation Principles, Historical Remarks 2 Classical Plate Theories 2.1 Small Deflections 2.2 Large Deflections 2.3 Kirchhoff Plate 2.4 Mindlin Plate 2.5 Von Kármán Plate 3 Laminates and Sandwiches 4 Direct Approach Based Plate Theory 4.1 Motivation 4.2 Direct Approach for Plates and Shells 4.3 Tensors and Their Symmetry Groups 5 Final Remarks References René de Borst Numerical methods for the modelling of debonding in composites 1 Introduction 2 Levels of observation 3 Three-dimensional framework 4 Zero-thickness interface elements 5 Solid-like shell formulation 6 Meshfree methods 7 The partition-of-unity concept 8 Delamination in a solid-like shell element 9 Discontinuous Galerkin methods References Ryszard Pyrz Micromechanics of Composites —Overall Elastic Properties 1 Introduction 2 Representative Volume Element 3 The Eshelby Equivalent Inclusion Method 3.1 Average strain and stress theorems 3.2 Relation between averages 3.3 The Eshelby solution 3.4 Equivalent inclusion method 4 The Mori-Tanaka Theory References Tomasz Sadowski Non-symmetric thermal shock in ceramic matrix composite (CMC) materials 1. Introduction to ceramic and metal matrix composites 2. Thermomechanical properties of CMC’s and MMC’s 2.1 Two-phase CMC with different elastic components 2.2 Two-phase CMC’s with plastic inclusions and MMC’s with elastic inclusions 2.2.1Thermomechanical properties 2.2.2 Modelling of the whole stress-strain curve fro MMC 2.2.3 Constitutive equations for FGM’s in 3-D formulation by self-consistent approach 2.2.3 Constitutive equations for FGM’s in 3-D formulation by self-consistent approach 3. Temperature field under transient thermal loading 3.1 FEA approach for heat transfer equation (26) 3.2 FD approach for heat transfer equation (26) 4. Transient thermal stress state 5. Thermal residual stress due to technological cooling process 5.1 Analytical models 5.2 Numerical models 6. Basic fracture mechanics concepts in functionally graded materials (FGM) 6.1 Rule of mixture to estimate the fracture toughness in FGMs 6.2 Crack-bridging approach to assess the fracture toughness 7. Non-symmetric thermal shock in monolithic ceramic and FGM strip 7.1 Transient temperature distribution during thermal shock 7.2 Thermal and residual stresses 7.3 Thermal stress intensity factor 7.4 Numerical example 8. Two-dimensional thermal shock problem in layered circular plates 8.1 Samples preparation and experimental procedure 8.2 Theoretical formulation 8.2.1 Thermal and mechanical properties of monolithic and FGM material 8.2.2 Heat conduction problem in FGM circular plate specimens 8.2.3 Determination of the thermal stress 8.3 Numerical example 9. Concluding remarks 10. References René de Borst J. Rethore M.-A. Abellan A precis of two-scale approaches for fracture in porous media 1. Introduction 2. Balance equations 3. Constitutive equations 4. Weak form of the balance equations 5. Micro-macro coupling 6. Discontinuities in a two-phase medium 7. Examples: stationary and propagating cracks 8. Concluding

O autorze

René de Borst ist Inhaber des Lehrstuhls für Bauingenieurwesen und Mechanik der Universität Glasgow, Großbritannien. Zuvor war er Professor an den Universitäten Delft und Eindhoven, Niederlande. Seine Schwerpunkte in Forschung und Lehre liegen auf der Bruchmechanik, Reibung und der numerische Modellierung in der Mechanik.

Blurb

This book presents the latest achievements in the field of composite materials modelling presented by the following authors:

- Prof. H. Altenbach (Germany)

- Prof. R. de Borst (The Netherlands)

- Prof. E. Craciun (Romania)

- Prof. R. Pyrz (Denmark)

- Prof. T.Sadowski (Poland)

The text gives a modern, up-to-date account of recent developments in the modelling of composite materials. Multiscale concepts, which are the new paradigm in (computational) mechanics, are at the heart of this text, and are treated in detail in the first three chapters of the book. Other relevant developments are covered in the later chapters of the book, beginning with the most relevant issue of coupling stress analysis and diffusion phenomena that arise from hygral and/or thermal loading, which are of crucial importance of the short and long-term resistance of composite materials.

The volume facilitates understanding of the basic principles of damage growth and fracture processes in various composite materials, including ceramics, polymers, metal-matrix composites and porous materials.