title: Recoverable Slippage Mechanism in Multilayer Graphene Leads to Repeatable Energy Dissipation.
abstract: Understanding the deformation mechanisms in multilayer graphene (MLG), an attractive material used in nanodevices as well as in the reinforcement of nanocomposites, is critical yet challenging due to difficulties in experimental characterization and the spatiotemporal limitations of atomistic modeling. In this study, we combine nanomechanical experiments with coarse-grained molecular dynamics (CG-MD) simulations to elucidate the mechanisms of deformation and failure of MLG sheets. Elastic properties of graphene sheets with one to three layers are measured using film deflection tests. A nonlinear behavior in the force vs deflection curves for MLGs is observed in both experiments and simulations: during loading/unloading cycles, MLGs dissipate energy through a "recoverable slippage" mechanism. The CG-MD simulations further reveal an atomic level interlayer slippage process and suggest that the dissipated energy scales with film perimeter. Moreover, our study demonstrates that the finite shear strength between individual layers could explain the experimentally measured size-dependent strength with thickness scaling in MLG sheets.
authors.affiliation: Department of Mechanical Engineering, Northwestern University , 2145 Sheridan Road, Evanston, Illinois 60208-3111, United States.|Department of Mechanics and Engineering Science, College of Engineering, Peking University , Beijing 100871, China.
authors.forename: Xiaoding
authors.initials: X
authors.lastname: Wei
authors.affiliation: Department of Civil and Environmental Engineering, Northwestern University , 2145 Sheridan Road, Evanston, Illinois 60208-3109, United States.
authors.forename: Zhaoxu
authors.initials: Z
authors.lastname: Meng
authors.affiliation: Department of Civil and Environmental Engineering, Northwestern University , 2145 Sheridan Road, Evanston, Illinois 60208-3109, United States.
authors.forename: Luis
authors.initials: L
authors.lastname: Ruiz
authors.affiliation: Department of Civil and Environmental Engineering, Northwestern University , 2145 Sheridan Road, Evanston, Illinois 60208-3109, United States.
authors.forename: Wenjie
authors.initials: W
authors.lastname: Xia
authors.affiliation: Department of Mechanical Engineering, Sungkyunkwan University , Suwon 440-746, Republic of Korea.
authors.forename: Changgu
authors.initials: C
authors.lastname: Lee
authors.affiliation: Department of Mechanical Engineering, Columbia University , New York, New York 10027, United States.
authors.forename: Jeffrey W
authors.initials: JW
authors.lastname: Kysar
authors.affiliation: Department of Mechanical Engineering, Columbia University , New York, New York 10027, United States.
authors.forename: James C
authors.initials: JC
authors.lastname: Hone
authors.affiliation: Department of Mechanical Engineering, Northwestern University , 2145 Sheridan Road, Evanston, Illinois 60208-3111, United States.|Department of Civil and Environmental Engineering, Northwestern University , 2145 Sheridan Road, Evanston, Illinois 60208-3109, United States.
authors.forename: Sinan
authors.initials: S
authors.lastname: Keten
authors.affiliation: Department of Mechanical Engineering, Northwestern University , 2145 Sheridan Road, Evanston, Illinois 60208-3111, United States.|Theoretical and Applied Mechanics, Northwestern University , 2145 Sheridan Road, Evanston, Illinois 60208-3111, United States.
authors.forename: Horacio D
authors.initials: HD
authors.lastname: Espinosa
keywords: energy dissipation; graphene; slippage; stacking nonlinearity; strength