Micromechanical Modelling of Non-Homogenous Materials by Meshless Methods

A detailed study of bi-material composites, using meshless methods (MMs), is presented in this paper. Firstly, representative volume elements (RVEs) for different bi-material combinations are analysed by the element-free Galerkin (EFG) method in order to confirm the effective properties of heterogeneous material through homogenization. The results are shown to be in good agreement with experimental results and those obtained using the finite element method (FEM) which required a higher node density. Secondly, a functionally graded material (FGM), with a crack, is analysed using the EFG method. This investigation was motivated by the possibility of replacing the distinct fibrematrix interface with a FGM interface. Finally, an illustrative example showing crack propagation, in a two-dimension micro-scale model of a SiC/Al composite is presented. 

Crack propagation in non-homogenous materials: Evaluation of mixed-mode SIFs, T-stress and kinking angle using a variant EFG method

A new variant of the Element-Free Galerkin (EFG) method, that combines the diffraction method, to characterize the crack tip solution, and the Heaviside enrichment function for representing discontinuity due to a crack, has been used to model crack propagation through non-homogenous materials. In the case of interface crack propagation, the kink angle is predicted by applying the maximum tangential principal stress (MTPS) criterion in conjunction with consideration of the energy release rate (ERR). The MTPS criterion is applied to the crack tip stress field described by both the stress intensity factor (SIF) and the T-stress, which are extracted using the interaction integral method. The proposed EFG method has been developed and applied for 2D case studies involving a crack in an orthotropic material, crack along an interface and a crack terminating at a bi-material interface, under mechanical or thermal loading; this is done to demonstrate the advantages and efficiency of the proposed methodology. The computed SIFs, T-stress and the predicted interface crack kink angles are compared with existing results in the literature and are found to be in good agreement. An example of crack growth through a particle-reinforced composite materials, which may involve crack meandering around the particle, is reported.

Natural Fibers for the Production of Green Composites

Development of green composite from natural fibers has gained increasing interests due to the environmental and sustainable benefits when compared with petroleum based non-degradable materials. However, a big challenge of green composites is the diversity of fiber sources, because of the large variation in the properties and characteristics of the lignocellulosic renewable resource. The lignocellulosic fibers/natural fibers used to reinforce green composites are reviewed in this chapter. A classification of fiber types and sources, the properties of various natural fibers, including structure, composition, physical and chemical properties are focused; followed by the impacts of natural fibers on composite properties, with identification of the main pathways from the natural fibers to the green composite. Furthermore, the main challenges and future trend of natural fibers are highlighted.

Cases, Materials and Text on National, Supranational and International Non-Discrimination Law

This casebook, the result of the collaborative efforts of a panel of experts from various EU Member States, is the latest in the Ius Commune Casebook series developed at the Universities of Maastricht and Leuven. The book provides a comprehensive and skilfully designed resource for students, practitioners, researchers, public officials, NGOs, consumer organisations and the judiciary. In common with earlier books in the series, this casebook presents cases and other materials (legislative materials, international and European materials, excerpts from books or articles). As non-discrimination law is a comparatively new subject, the chapters search for and develop the concepts of discrimination law on the basis of a wide variety of young and often still emerging case law and legislation. The result is a comprehensive textbook with materials from a wide variety of EU Member States. The book is entirely in English (i.e. materials are translated where not available in English). At the end of each chapter a comparative overview ties the material together, with emphasis, where appropriate, on existing or emerging general principles in the legal systems within Europe.
The book illustrates the distinct relationship between international, European and national legislation in the field of non-discrimination law. It covers the grounds of discrimination addressed in the Racial Equality and Employment Equality Directives, as well as non-discrimination law relating to gender. In so doing, it covers the law of a large number of EU Member States, alongside some international comparisons.
The Ius Commune Casebook on Non-Discrimination Law
- provides practitioners with ready access to primary and secondary legal material needed to assist them in crafting test case strategies.
- provides the judiciary with the tools needed to respond sensitively to such cases.
- provides material for teaching non-discrimination law to law and other students.
- provides a basis for ongoing research on non-discrimination law.
- provides an up-to-date overview of the implementation of the Directives and of the state of the law.
This Casebook is the result of a project which has been supported by a grant from the European Commission's Anti-Discrimination Programme.

A Tunable Split Resonator Method for Non-destructive Permittivity Characterization

The split cylinder resonator method is improved for nondestructive and accurate measurement for low permittivity materials at multiple frequency points. The dielectric constants of flat substrate materials are calculated based on a rigorous mode match analysis of the TE/sub 011/ mode. The loss tangent is also approximately calculated. The dielectric properties of two commercial substrates have been measured at multiple frequencies. The results demonstrate that this technology is capable of accurately characterizing the dielectric properties of flat substrate materials versus frequency in a nondestructive way.