Tailoring the Mechanical Behaviour of Ceramic Laminates Using a Non-Periodic Multilayer Architecture

0435045 - ÚFM 2015 RIV DE eng O - Ostatní výsledky
Bermejo, R. - Chang, Y. - Chlup, Zdeněk - Ševeček, O. - Messing, G.L. - Danzer, R.
Tailoring the Mechanical Behaviour of Ceramic Laminates Using a Non-Periodic Multilayer Architecture.
2014
Institucionální podpora: RVO:68081723
Klíčová slova: Laminate * Ceramic * Mechanical behaviour
Kód oboru RIV: JH - Keramika, žáruvzdorné materiály a skla

The low resistance to crack propagation, flaw-size dependence of strength and poor damage tolerance have limited the use of monolithic ceramics as advanced engineering materials for certain applications. Much progress has been made to design ceramic composites to improve fracture toughness. At the macroscopic scale, composite materials can be arranged according to various configurations (i.e. connectivity [1]), such as the 2-2 symmetric laminate composites which consist of alternate layers of different compositions ordered in a periodic architecture. These structures provide the opportunity for tailoring the properties by designing composite build-up strategies [2]. Recent work has shown that the combination of layers in a non-periodic manner can be more effective in arresting the propagation of cracks than the commonly used periodic designs. The location and thickness of the layers designed with compressive stresses can be optimized to maximize the crack growth resistance of the multilayer system [3]. A theoretical approach based on linear elastic fracture mechanics is derived to explain the stable/unstable crack propagation in laminate composites under mechanical loading. Predictions of threshold strength and fracture toughness are validated with experiments on ceramic laminates designed with 2-2 connectivity. New design concepts for tailoring the resistance to crack propagation in laminates are presented in this work, based on 1-1 connectivity composites (see Ref. 1). Experimental findings, supported by a fracture mechanics model, demonstrate that placing the first compressive layer closer to the tensile surface and increasing this layer’s thickness yields a significant increase in the threshold strength (~470 MPa) and apparent fracture toughness (~17 MPa•m1/2). The design of 1-1 layered architectures allows tailoring the location and thickness of the compressive layers, thus opening new possibilities for design of multilayer structures with higher reliability.
Trvalý link: http://hdl.handle.net/11104/0239590