surface fractal analysis for estimating the fracture energy absorption of nanoparticle reinforced composites表面分形分析估算纳米颗粒增强复合材料的断裂能量吸收.pdf

Materials 2012, 5, 922-936; doi:10.3390/ma5050922 OPEN ACCESS materials ISSN 1996-1944 /journal/materials Article Surface Fractal Analysis for Estimating the Fracture Energy Absorption of Nanoparticle Reinforced Composites Brahmananda Pramanik *, Tezeswi Tadepalli and P. Raju Mantena Department of Mechanical Engineering, University of Mississippi, University, MS 38677, USA; E-Mails: tadepali@ (T.T.); meprm@ (P.R.M.) * Author to whom correspondence should be addressed; E-Mail: bpramani@; Tel.: +1-662-915-5990; Fax: +1-662-915-1640. Received: 19 March 2012; in revised form: 8 May 2012 / Accepted: 11 May 2012 / Published: 23 May 2012 Abstract: In this study, the fractal dimensions of failure surfaces of vinyl ester based nanocomposites are estimated using two classical methods, Vertical Section Method (VSM) and Slit Island Method (SIM), based on the processing of 3D digital microscopic images. Self-affine fractal geometry has been observed in the experimentally obtained failure surfaces of graphite platelet reinforced nanocomposites subjected to quasi-static uniaxial tensile and low velocity punch-shear loading. Fracture energy and fracture toughness are estimated analytically from the surface fractal dimensionality. Sensitivity studies show an exponential dependency of fracture energy and fracture toughness on the fractal dimensionality. Contribution of fracture energy to the tot