Classical micromechanics modeling of nanocomposites with carbon nanofibers and interphase

Abstract

A micromechanics parametric study was performed to investigate the effect of carbon nanofiber morphology (i.e. hollow vs. solid cross-section), nanofiber waviness, and both nanofiber–resin interphase properties and dimensions on bulk nanocomposite elastic moduli. Mori–Tanaka and self-consistent models were developed for composites containing heterogeneities with multilayered coatings. For a given nanofiber axial force–displacement relationship, the elastic modulus for hollow nanofibers can significantly exceed that for solid nanofibers resulting in notable differences in bulk nanocomposite properties. In addition, the development of a nanofiber–resin interphase had a notable effect on the bulk elastic moduli. Consistent with results from the literature, small degrees of nanofiber waviness resulted in a significant decrease in effective composite properties.

Southern Regional Center for Lightweight Innovative Design

“…This underscores the importance of the contribution of the interphase to overall composite properties. Similar results were obtained when calculating the effective transverse modulus (Yu et al, 2011a).…”

“…Mean field approaches have been used to investigate the effect of solid nanofibers or nanoplatelets on bulk nanoreinforced matrix properties (Fisher et al, 2003;Liu and Brinson, 2008), and have been modified to account for the effect of varying degrees of nanofiber waviness (Fisher et al, 2003). As part of the current study, Yu et al (2011a) developed MTM and SCM models for predicting effective elastic properties for nanocomposites containing hollow wavy nanofibers surrounded by an arbitrary number of interphase layers. A parametric study was performed investigating the effect of hollow nanofiber wall thickness, nanofiber-matrix interphase thickness and elastic properties, and degree of nanofiber waviness on effective nanocomposite properties.…”

“…Also, a normalized nanofiber modulus (E F /E m ) consistent with VGCNF/VE nanocomposites was used. Figure 12a shows a plot of the effective longitudinal modulus, E L , from (Yu et al, 2011a) as a function of normalized interphase thickness (t/R) for straight hollow fibers (aspect ratio, L/D = 100; volume fraction, 0.63 v%) based upon the MTM. The interphase properties were varied over the range 0.5 ≤ E i /E m ≤ 20 in order to encompass both relatively compliant and stiff interphases.…”

“…A parametric study investigating the effect of interphase properties on bulk nano-phased matrix properties was previously performed by Yu et al (2011a) and is briefly summarized in this work. That study accommodated both hollow and wavy nanofibers.…”

The effect of general statistical fiber misalignment on predicted damage initiation in composites

“…Due to the proven ability of the HFGMC model to analyze various nonlinear effects, the proposed method could also be extended to consider material nonlinearity such as damage and inelasticity within the constituents and to consider the thermal-mechanical response of composites. Additional potential applications include analysis of composites with given fiber paths, short/nanofiber composites with known fiber alignment/waviness (c.f., [38]) and multiscale analysis within laminated plate theories and finite element analyses, which could be used to capture misalignment effects on the response of woven composites. Application to biological materials, as has been done with the microsphere model, is also possible.…”