EFFECT OF NANOSTRUCTURE IN NACRE: A MULTISCALE MODELING APPROACH Dinesh Katti 1 , Member ASCE Kalpana Katti 2 , Jingpeng Tang 3 ,and Mehmet Sarikaya 4 ABSTRACT This paper describes a multiscale modeling approach developed to understand the effect of nano and microarchitecture and nanostructural nuances in nacre-based nanocomposites. Results of simulations on models incorporating the nano and microarchitecture and mineral contacts are presented. The nanomechanical properties are evaluated using nanoindentation tests. Based on these results, the influence of various components of nacre architecture including inorganic-organic interphase and the mineral contacts on bulk mechanical response is discussed. Keywords: Finite Element Modeling, Nacre, Biomimetics, Nanoindentation, Mineral Contacts, Nanotechnology INTRODUCTION At this turn of the century it is becoming increasingly clear that nanoscience and nanoengineering will lead to unprecedented understanding and control over the fundamental building blocks of all physical things.(IWGN report) One useful methodology in the ability to engineer materials at the nanoscale is a materials design driven by simulations. This is particularly true in the field of biomimicking wherein microstructures and fabrication techniques mimicking biological systems are desired (Winwright, 1982). Living organisms produce materials with physical properties that surpass those of analogous synthetic technological materials with similar phase compositions. This is mainly due to the fact that biological materials are highly organized from the molecular, to the nanometer, and to the macro scale, often, in a hierarchical manner providing an ordered continuity at all dimensional scales of the structure. Our efforts focus on applying advanced nanoscale characterization techniques to continuum based numerical models to lead a biomimetic materials design with simulations. The purpose of this study is to develop a modeling procedure that incorporates nanoscale responses at surfaces 1 Dept. of Civil Eng., North Dakota State University, Fargo, ND 58105. E-mail: Dinesh.Katti@Ndsu.Nodak.Edu 2 Dept. of Civil Eng., North Dakota State University, Fargo, ND 58105. 3 Dept. of Civil Eng., North Dakota State University, Fargo, ND 58105. 4 Dept. of Mat. Sci. & Eng., University of Washington, Seattle, WA 98125.