research

Xueju (Sophie) Wang, Department of Materials Science and Engineering; Polymer Program, Institute of Materials Science, University of Connecticut

Improved formulas of extensional and bending stiffnesses of isotropic rectangular nanorods are derived. These formulas reduce to the existing widely used formulas for a special choice of material parameters, i.e., when the surface Poisson's ratio and the bulk Poisson's ratio match thus highlighting the limitation of the existing formulas.

Dear Colleague

Our (open access) paper on the post-touchdown dynamics of an electrostatically actuated MEMS device has just appeared in IJSS:

Nate N. Goldberg and Oliver M. O'Reilly, Electrostatically actuated MEMS in the post-touchdown regime: The thin-dielectric limit and a novel reduced-order model for release dynamics"

Graphical Abstract can be found here

Dear colleagues, 

We invite you to read our recent article, which proposes a multiband homogenization scheme and has been accepted to appear in JMPS (https://www.sciencedirect.com/science/article/pii/S002250962200182X)

Multiband homogenization of metamaterials in real-space: Higher-order nonlocal models and scattering at external surfaces

For students who are attending IMECE this year, there is a wonderful opportunity for you to apply for a travel award ($1000/grad, $500/under). There are a total of 50 travel awards for you to claim. You also have a possibility to win cash awards ($2000 total). You need to submit a poster abstract by 6/29. See https://event.asme.org/IMECE/Program/NSF for more details. 

In linear elasticity, universal displacements for a given symmetry class are those displacements that can be maintained by only applying boundary tractions (no body forces) and for arbitrary elastic constants in the symmetry class. In a previous work, we showed that  the larger the symmetry group, the larger the space of universal displacements. Here, we generalize these ideas to the case of anelasticity. In linear anelasticity, the total strain is additively decomposed into elastic strain and anelastic strain, often referred to as an eigenstrain.

In this work, a new mixed finite element formulation is presented for the analysis of two-dimensional compressible solids in finite strain regime. A three-field Hu-Washizu functional, with displacement, displacement gradient and stress tensor considered as independent fields, is utilized to develop the formulation in spatial configuration. Certain constraints are imposed on displacement gradient and stress tensor so that they satisfy the required continuity conditions across the boundary of elements.

For a given class of materials, universal deformations are those that can be maintained in the absence of body forces by applying only boundary tractions.  Universal deformations play a crucial role in nonlinear elasticity. To date, their classification has been accomplished for homogeneous isotropic solids following Ericksen's seminal work, and  homogeneous anisotropic solids and inhomogeneous isotropic solids in our recent works. In this paper we study universal deformations for inhomogeneous anisotropic solids defined as materials whose energy function depends on position.

Due to the inherent viscoelasticity of constituent matrix and the possibility of long-term storage, space deployable structures made of composites are likely to exhibit relaxation in the stored strain energy, which may degrade their deployment performance. This paper presents a bottom-up finite element based multiscale computational strategy that bridges the experimentally measurable properties of constituent fibers and matrix to numerical predictions of viscoelastic behavior of composite laminates and general shell structures.

To be published on

Civil Engineering Research & Technology

ISSN: 2754-4982

I am happy to share our recent work, that has been published in the Physical Review B journal. I would be happy to share the paper with anyone interested, let me know if you cannot access the paper otherwise.

By Yuzhen Chen, Tianzhen Liu, Lihua Jin*

Dear iMechanicians,

I would like to share our recent work published in Phys. Rev. Fluids on the statics and dynamics of droplets on lubricated surfaces: 

Droplets on lubricated surfaces: The slow dynamics of skirt formation

Zhaohe Dai and Dominic Vella

By Yuzhen Chen, Alexa S. Kuenstler, Ryan C. Hayward*, Lihua Jin*

50 days of the free download link

https://www.sciencedirect.com/science/article/pii/S2352492822005682?dgci...

Permanent link

https://www.sciencedirect.com/science/article/abs/pii/S2352492822005682

We present a study on planar equilibria of a terminally loaded elastic rod wrapped around a rigid circular capstan. Both frictionless and frictional contact between the rod and the capstan are considered. We identify three cases of frictionless contact -- namely where the rod touches the capstan at one point, along a continuous arc, and at two points. We show that, in contrast to a fully flexible filament, an elastic rod of finite length wrapped around a capstan does not require friction to support unequal loads at its two ends.