Wiyao Azoti

State of the Art of Graphene Lightweighting Nanocomposites for Automotive Applications

Abstract This work presents a state of the art (SotA) of recent developments related to the lightweighting of automotive structure by introduction graphene as material constituents. It proposes some innovative directions in terms of technological manufacturing and process for a better understanding of the graphene contribution for enhancing multifunctional properties of nanocomposites. Likewise, the general context of research trends is presented along with the novel composites solutions for the design of lightweight materials using graphene-based polymer composites. The need for developing a modeling strategy is discussed in terms of simulation and optimization of the multifunctional properties as well as the hierarchical modeling of hybrid composites. The large-scale production is presented through the existing process and manufacturing engineering. And finally, the industrial feasibility of such composite is presented by a demonstrator development and the life-cycle analysis.

Mechanical Prediction of Graphene-Based Polymer Nanocomposites for Energy-Efficient and Safe Vehicles

Abstract This work investigates efficient ways of lightweighting vehicles structures based on Graphene-related materials (GRMs). An integration of Graphene as polymer reinforcements within composite materials for energy-efficient and safe vehicles (EESVs) is addressed with respect to some technological challenges, for instance, the lack of constitutive material models for high-performance structural applications. Therefore, accurate material models need to be developed to support simulation of structural design for these vehicles. A multiscale modeling of Graphene-reinforced polymer composite is elaborated, and using the Mori-Tanaka micromechanics scheme, the effective nonlinear behavior is predicted for various microparameters such as the aspect ratio and volume fractions. The results show an enhancement of the equivalent macro-stress-strain response when the aspect ratio is low corresponding to platelets-like inclusions. Also, the volume fraction is seen to have a good improvement on the composite response. The results highlight the effect of Graphene platelets versus carbon and glass fibers in the design of lightweight structures with enhanced mechanical responses and by consequence a CO 2 emissions reduction.

Micromechanics Modelling of Graphene Platelets Reinforced Polymer Composite Materials With Imperfect Interfaces

This work investigates the elasto-plastic response of platelets-like inclusions reinforced polymer composites showing an imperfect interface. The solution of the heterogeneous material problem is solved through a kinematic integral equation. To account for the interfacial behaviour, a linear spring model LSM is adopted, leading to an expression of the modified Eshelbys tensor. As a consequence, the interfacial contributions with respect to the strain concentration tensor within each phase as well as in the average strain field are described by a modified version of the Mori-Tanaka scheme for the overall response. The non-linear response is established in the framework of the J2 flow rule. An expression of the algorithmic tangent operator for each phase can be obtained and used as uniform modulus for homogenisation purpose. Numerical results are conducted on graphene platelets GPL-reinforced polymer PA6 composite for several design parameters such as GPL volume fraction, aspect ratio and the interfacial compliance. These results clearly highlight the impact of the aspect ratio as well as the volume fraction by a softening in the overall response when imperfection is considered at the interface. Present developments are analytical-based solutions. They constitute a theoretical framework for further multi-scale applications in automotive. The crashworthiness simulation incorporating an influence of the interfacial behaviour on the strain energy absorption SEA is of interest.