Fiber-reinforced composites occupy an expanding market of mechanically demanding applications such as prosthetic joints, vehicle chassis, and body armors. Such composites typically consist of stiff fibers surrounded by a polymeric matrix, with a thin interfacial region coupling the two phases. The performance of composites in mechanically demanding applications depends in part upon their failure mechanisms, such as debonding at the interface between the phases or fracture within either phase. The mechanical and chemical nature of the interphase layer, in particular the strength of coupling between the phases, influences which mechanisms are most critical for performance. Here, we describe our computational studies of composite materials containing glass fibers and a promising new thermoset matrix, polydicyclopentadiene (pDCPD). The novelty of pDCPD necessitates the design of a new glass fiber coating (i.e., a sizing package) to make the fibers compatible with the matrix. We approach this design process using computational techniques at multiple length scales, in synchrony with experimental measurements. At the nanoscale, we employ reactive all-atom molecular dynamics (MD) simulations to examine the effects of chemistry and surface density of coupling agents on the interfacial strength and mechanisms of failure. The MD results are used to parameterize higher-level finite element (FE) models of experimental measurement devices, enabling information to flow between the length scales that influence the overall design process.

Computational studies of interfacial fracture in polymer composite materials

253rd National Meeting (2017)

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