Shaofei Jiang

Wetting and Dewetting Transitions on Submerged Superhydrophobic Surfaces with Hierarchical Structures

The wetting transition on submersed superhydrophobic surfaces with hierarchical structures and the influence of trapped air on superhydrophobic stability are predicted based on the thermodynamics and mechanical analyses. The dewetting transition on the hierarchically structured surfaces is investigated, and two necessary thermodynamic conditions and a mechanical balance condition for dewetting transition are proposed. The corresponding thermodynamic phase diagram of reversible transition and the critical reversed pressure well explain the experimental results reported previously. Our theory provides a useful guideline for precise controlling of breaking down and recovering of superhydrophobicity by designing superhydrophobic surfaces with hierarchical structures under water.

Mechanical analysis of functionally graded graphene oxide-reinforced composite beams based on the first-order shear deformation theory

ABSTRACT This paper investigates the mechanical behaviors of functionally graded multilayer nanocomposite beams reinforced with a low content of single-layer graphene oxide powders (GOPs). The material properties of GOP nanocomposites are estimated. The first-order shear deformation theory and Hamiltons principle are employed to deal with the motion equations. Parametric studies are conducted to examine the effects of distribution pattern and weight fraction of GOPs, slenderness ratio and boundary condition on the bending, buckling, and vibration of GOP beams. The results show that GOP is superior to the single-walled carbon nanotubes (SWCNTs) and multi-walled carbon nanotubes (MWCNTs) in reinforcing the mechanical behaviors of polymer nanocomposite.

Hygroscopic influence on bistable characteristics of antisymmetric composite cylindrical shells: An experimental study:

This paper investigates the effect of moisture on bistable characteristics of antisymmetric composite cylindrical by using experimental and finite element method. The bistable characteristics are characterized by the curvatures of antisymmetric composite cylindrical shells in different stable states and snap processes between the two stable states which are indicated by the load–displacement curve and snap load. The manufactured specimens after dried in the oven are immersed in distilled water to full saturation and the saturated salt solutions (MgCl2) to full saturation. The specimen achieves different moisture that is immersed in distilled water at the different period until full saturation and in the saturated salt solution (MgCl2) with the same period of saturation in distilled water. Specimens with different moisture are then mechanically loaded on a testing machine to transform between two stable states. Load–displacement curves are recorded in the computer, from which the snap loads can be found. After the test, the principal and twisting curvatures are captured by a digital image processing. The results are contrasted with hygroscopic influence on another kind of bistable composite structure (asymmetric cross-ply laminates) in this paper. The results show that the shapes and snap loads of antisymmetric composite cylindrical shells are influenced by the moisture increasing.