ICF100326OR DYNAMIC DELAMINATION IN THROUGH-THICKNESS REINFORCED DCB SPECIMENS N. Sridhar1*, I. J. Beyerlein2, B. N. Cox 1 and R. Massabò3 1Rockwell Science Center, 1049 Camino Dos Rios, Thousand Oaks, CA 91360, U.S.A. 2Los Alamos National Laboratory, New Mexico, U.S.A 3 Department of Structural and Geotechnical Engineering, University of Genova, Italy ABSTRACT Bridged crack models using beam theory formulation have proved to be effective in the modeling of quasistatic delamination crack growth in through thickness reinforced structures. In this paper, we model dynamic crack propagation in these structures with the beam theory formulation. Steady state crack propagation characteristics unique to the dynamic case are first identified. Dynamic crack propagation and the energetics of steady state dynamic crack growth for a Double Cantilever beam (DCB) configuration loaded with a flying wedge is examined next. We find that steady state crack growth is attainable for this loading configuration provided certain conditions are satisfied. KEYWORDS Dynamic, Delamination, Crack, Bridging, DCB, Stitching, Energy Release Rate INTRODUCTION Through thickness reinforcement of various kinds, including stitched or woven continuous fiber tows and metallic or fibrous short rods, has been developed to address the delamination problem in structural composite laminates. Substantial experimental evidence shows that through thickness reinforcement dramatically alters the delamination characteristics for the better under both static and dynamic loading conditions. For static loading, a fundamental theory based on observations of essential mechanisms is now mostly in place [1-6]. The mechanics of crack bridging by the through thickness tows have been mapped out, with governing length scales and material parameters identified [1-6]. However, equivalent fundamental knowledge and models for dynamic delamination do not exist. This paper deals with the delamination mechanics for through thickness reinforced structures under dynamic crack propagation conditions. A beam theory formulation is adopted and certain crack
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