Estimating the Cohesive Zone Model Parameters for Carbon Nanotube–Polymer Interface Using Inverse Finite Element Approach Available to Purchase

During machining of carbon nanotube (CNT)-polymer composites, the failure of the polymer elements occurs at the CNT-polymer interface. The interfacial behavior that can be represented by a cohesive zone model (CZM) is mainly influenced by two parameters, viz., interfacial strength and fracture energy. The objective of this study is to estimate these two specific CZM parameters using an inverse finite element (FE) simulation approach that works based on an iterative error minimization procedure. Nanoindentation tests have been conducted on a CNT-polyvinyl alcohol (PVA) composite sample containing 4 wt% multi-walled nanotubes (MWNTs). A 2D axisymmetric FE model of nanoindentation has been developed. This micro-structure based model considers the CNT, the PVA, and the cohesive zone of interface as three individual phases. The unknown interfacial parameters are determined by minimizing the error between the simulation load-displacement curve and the experimental results. The interfacial strength and the fracture energy at the CNT-PVA interface are estimated to be approximately 40 MPa and 16e−3 J/m², respectively. This approach provides a convenient framework to understand the role of the CZM parameters at the interface between the CNT and polymer matrix.