Fully coupled thermo-mechanical cohesive zone model with thermal softening: Application to nanocomposites

A computational framework is proposed for coupled thermo-mechanical analyses of interface separation and heat transport in carbon nanotubes (CNTs) enhanced composites. The numerical approach adopted is based on a newly developed cohesive zone finite element, with fully coupled interactions between load and heat transfer. The load transfer behavior is described by a damage (bilinear) model that can account for mixed-mode separation and for thermal degradation of the interface mechanical properties. The interface conductance consists of the conductance of connective bond, air and contact and is coupled to the cohesive zone damage and crack closure. The element is then used to numerically study the thermoelastic properties of nanocomposites. Due to the possibility of low interface conductance, composites containing higher volume fraction or better alignment of CNT may not have more favorable mechanical behaviors in thermo-mechanical loading. Contributions of connective, contact and air conductance on the heat transfer in the damaged cohesive zone are investigated. The proposed computational framework is an extension of mechanical only finite element analyses of the CNT-composites, providing an alternative to molecular dynamics in carrying out multiphysics simulation of CNT-composites with less computational cost. The present work provides valuable insight into understanding the interaction of the load and heat transfers in the CNT-composites. the evolution of interface conductance in the damaged interface and the effect of interface damage on the overall performance of the composite. (C) 2019 Elsevier Ltd. All rights reserved.