research

A novel micromorphic beam theory that considers the exact shape and size of the beam’s microstructure is developed. The new theory complements the beam theories that are based on the classical mechanics by modeling the shape and size of the beam’s microstructure. This theory models the beam with a microstructure that has shape and size and exhibits microstrains that are independent of the beam’s macroscopic strains.

In this paper, we investigate the surface roughness-dependence of buckling of beam-nanostructures. A new variational formulation of buckling of Euler-Bernoulli rough beams is developed based on the Hamil- ton’s principle. The equation of motion of the beam is obtained with a coupling term that depends on the beam surface roughness. Exact solutions are derived for the buckling configurations and the pre-buckling and postbuckling vibrations of simply supported structures.

Current designs of artificial metamaterials with giant Poisson’s ratios proposed microlattices that secrete the transverse displacement nonlinearly varies with the longitudinal displacement, and the Poisson’s ratio depends on the applied strain (i.e., tailorable Poisson’s ratio). Whereas metamaterials with tailorable Poisson’s ratios would find many important applications, the design of a metamaterial with a giant Poisson’s ratio that is constant over all the material deformation range has been a major challenge.

In this paper, we put water flow under scrutiny to report radial distributions of water viscosity within hydrophobic and hydrophilic nanotubes as functions of the water-nanotube interactions, surface wettability, and nanotube size using a proposed hybrid continuum-molecular mechanics. Based on the computed viscosity data, phase diagram of the phase transitions of confined water in nanotubes is developed. It is revealed that water exhibits different multiphase structures, and the formation of one of these structures depends on many parameters.