research

Petals and leaves are usually curled and exhibit intriguing morphology evolution upon growth, which contributes to their important biological functions. To understand the underlying morphoelastic mechanism and to determine the crucial factors that govern the growth-induced instability patterning in curved petals and leaves, we develop an active thin shell model that can describe variable curvatures and spontaneous growth, within the framework of general differential geometry based on curvilinear coordinates and hyperelastic deformation theory.

The physical properties of graphene nanoribbons (GNRs) are closely related to their morphology; meanwhile GNRs can easily slide on surfaces (e.g., superlubricity), which may largely affect the configuration and hence the properties. However, the morphological evolution of GNRs during sliding remain elusive. We explore the intriguing tail swing behavior of GNRs under various sliding configurations on Au substrate. Two distinct modes of tail swing emerge, characterized by regular and irregular swings, depending on the GNR width and initial position relative to the substrate.

I would like to share our following paper published recently in International Journal of Plasticity:

Modeling and simulation of dynamic compression of Bulk Metallic Glasses at room and elevated temperatures using split Hopkinson pressure bar setup

Our recent paper is accessible freely for 50 days from this link: https://authors.elsevier.com/a/1iaz87NHxQgzz

Key findings of this paper include a 7-fold strength increase in crystals with chain ends at higher strain rates, a shift in failure mode from chain end sliding to chain scission, and the influence of molecular weight on the failure mode.

The problem of the detachment of a flat indenter from a plane adhesive viscoelastic strip of thickness “b” is studied. For any given retraction speed, three different detachment regimes are found: (i) for very small “b” the detachment stress is constant and equal to the theoretical strength of the interface, (ii) for intermediate values of “b” the detachment stress decays approximately as b^{-1/2}1/2, (iii) for thick layers a constant detachment stress is obtained corresponding to case the punch is detaching from a halfplane.

If you have NSF-funded projects, please encourage your students to submit posters to ASME IMECE topic 16-1 and 16-2 (REU only)! NSF provides 30+ travel awards ($1200 each) to cover student travel cost, plus chances to win poster competition awards.

Journal Club for February 2024: Mechanics in Solid-State Batteries: Mechanical Properties, Interfacial Failure, and Multiphysics Modeling

Wei Li⁼, Ruqing Fang⁼, Junning Jiao, Juner Zhu*

Department of Mechanical and Industrial Engineering, Northeastern University

* Corresponding author: j.zhu [at] northeastern.edu
= Authors with equal contributions to this article

By considering the frictional sliding of randomly distributed entanglements within the polymer network upon mechanical stretches, we develop a constitutive theory to describe the large stretch behaviors of highly entangled hydrogels. 

doi: https://doi.org/10.1007/s10483-024-3076-8