Monotonic and hysteretic in-plane behaviour of graphene through an atomistic FE model

This paper presents a computational study on the monotonic and hysteretic in-plane behaviour of graphene. With this purpose, atomistic finite element models of graphene were developed taking into account the degradation of stiffness and strength through an elastic-plastic model. The study extends the typical unidirectional tests (in armchair and zigzag directions) to the bidirectional test and the shear test, establishing a consistent and comprehensive set of both elastic and strength properties. The mechanical properties obtained from the monotonic analyses (elastic and strength properties) are validated from the comparison with those available in the literature (experimental, density functional theory, molecular dynamic simulations and finite element models). The strain-softening behaviour of graphene is assessed through these atomistic models. The failure modes of graphene sheets in different loading tests are detailed and its load carrying capacity is explained. Finally, the hysteretic behaviour of graphene is discussed. The stress-strain curves and the variation of dissipated energy with the strain are given for different number of cycles. Then, some concluding remarks are drawn.