Micromechanics and structural response of functionally graded , 3 particulate - matrix , fiber - reinforced composites

24 Reinforcement of fibrous composites by stiff particles embedded in the matrix offers the 25 potential for simple, economical functional grading, enhanced response to mechanical 26 loads, and improved functioning at high temperatures. Here, we consider laminated plates 27 made of such a material, with spherical reinforcement tailored by layer. The moduli for this 28 material lie within relatively narrow bounds. Two separate moduli estimates are consid29 ered: a ‘‘two-step” approach in which fibers are embedded in a homogenized particulate 30 matrix, and the Kanaun–Jeulin (Kanaun, S.K., Jeulin, D., 2001. Elastic properties of hybrid 31 composites by the effective field approach. Journal of the Mechanics and Physics of Solids 32 49, 2339–2367) approach, which we re-derive in a simple way using the Benveniste (1988) 33 method. Optimal tailoring of a plate is explored, and functional grading is shown to 34 improve the performance of the structures considered. In the example of a square, simply 35 supported, cross-ply laminated panel subjected to uniform transverse pressure, a modest 36 functional grading offers significant improvement in performance. A second example sug37 gests superior blast resistance of the panel achieved at the expense of only a small increase 38 in weight. 39 ! 2008 Elsevier Ltd. All rights reserved. 40 41 42