2-D "tension-shear chain" model (Ref.1-3) is well known successfully capturing the basic mechanical features of staggered structures in shell-like biomaterials. Our recent paper appeared in Comp. Sci. Tech. developed a three-dimensional (3D) "tension-shear chain" theoretical model to predict the mechanical properties of unidirectional short fiber reinforced composites, and especially to investigate the distribution effect of short fibers.

Recent years have witnessed intense interest in multifunctional surfaces that can be designed to switch between different functional states with various external stimuli including electric field, light, pH value, and mechanical strain. The present paper is aimed to explore whether and how a surface can be designed to switch between superhydrophobicity and superhydrophilicity by an applied strain.

We investigate bending behaviors of graphene nanoribbons (GNRs) induced by surface adsorption of hydrogen atoms or molecules. At low adsorption coverage, it is shown that the chemical adsorption of hydrogen atoms causes a GNR to bend away from the adsorbed atoms while the physical adsorption of hydrogen molecules causes it to bend toward the adsorbed molecules. Interestingly, these trends are reversed at high adsorption coverage. There exists a range of linear responses for both chemical and physical adsorptions, which points to promising applications of GNRs as sensitive chemical-/biosensors.

The paper is available online in Applied Physics Letters (Vol.98, Issue 12):

Load-bearing biological materials such as shell, mineralized tendon and bone exhibit 2-7 levels of structural hierarchy based on constituent materials (biominerals and proteins) of relatively poor mechanical properties. A key question that remains unanswered is what determines the number of hierarchical levels in these materials. Here we develop a quasi-self-similar hierarchical model to show that,

Unidirectional nanocomposite structures with parallel staggered platelet reinforcements are widely observed in natural biological materials. Our recent paper, published in J. Mech. Phys. Solids, is aimed at an investigation of the stiffness, strength, failure strain and energy storage capacity of a unidirectional nanocomposite with non-uniformly or randomly staggered platelet distribution.