Bin Liu's blog
Mechanics interpretation on the bending stiffness and wrinkled pattern of graphene.
In this paper we attempt to answer two questions on graphene from a mechanic’s viewpoint: why does this one-atom-thick monolayer have finite bending stiffness to ensure its stability? and what is its wrinkle mechanism? As for the first question, it is found that the repulsive residual internal moment in the bond angle can lead to a nonzero bending stiffness, which makes the graphene flat. Together with long-range attraction among atoms, such as van der Waals forces, a graphene prefers to have a self-buckling wrinkled configuration with many waves.
Kinetic Energy-Based Temperature Computation in Non-Equilibrium Molecular Dynamics Simulation
The velocities of atoms in MD simulation are not objective quantities, which depend on the choice of the reference frame and sample size. In our previous study (node/3181), we discussed how to overcome this non-objectivity and compute the atomic stress objectively. In this blog, our newly published paper on temperature computation is attached, and the abstract is as follows.
Direct influence of residual stress on the bending stiffness of cantilever beams
Although the cantilever beam has been widely used as a sensor to measure various physical quantities, important issues such as how residual stress affects its bending stiffness and what are the underlying physical origins have not been fully understood. We perform both theoretical analyses and finite-element simulations to demonstrate for the first time that without changing the material tangent stiffness, residual stress within the beam can directly influence the bending stiffness of the beam. This direct influence arises from two origins: geometry nonlinearity and Poisson’s ratio effect.
An effective bead-spring model for polymer simulation
An effective bead-spring model combining the advantages of large time steps of traditional bead-rod models and computational rigor of traditional bead-spring models is proposed to simulate the dynamic behaviors of flexible polymer chains with arbitrary longitudinal stiffness. The proposed model can be used to simulate many types of polymer chains or networks with different chain elasticity via a unified integration scheme with reasonably large time steps. The paper can be found at http://dx.doi.org/10.1016/j.jcp.2007.11.012