preprint

Dear colleagues,

We invite you to see the preprint of our new paper Lagrangian approach to origami vertex analysis: Kinematics that will appear in Philosophical Transactions of the Royal Society A. Here we show how the Lagrangian approach to origami facilitates the exploitation of symmetry, formulate reduced order compatibility conditions for some symmetric foldings, and obtain analytical expressions for the kinematics of some degree 6 and degree 8 origami vertices.

We investigate the mechanics and stability of a nanoscale origami crease via a combination of equilibrium and nonequilibrium statistical mechanics. We identify an entropic torque on nanoscale origami creases, and find stability properties have a nontrivial dependence on bending stiffness, radii of curvature of its creases, ambient temperature, its thickness, and its interfacial energy.

This article will appear in Soft Matter (https://doi.org/10.1039/D3SM00664F)

A Dimensionally-Reduced Nonlinear Elasticity Model for Liquid Crystal Elastomer Strips with Transverse Curvature

Kevin LoGrande (1, 2), M. Ravi Shankar (3) and Kaushik Dayal (1, 4, 5)

1Department of Civil and Environmental Engineering, Carnegie Mellon University

2Computation and Information Sciences Directorate, CCDC Army Research Lab

Dear colleagues,

We invite you to see the preprint of our new paper "Statistical mechanics of a dielectric polymer chain in the force ensemble" that will appear in Journal of the Mechanics and Physics of Solids. Here we compute the electroelasticity of single polymer chains using both analytical approximations and novel MCMC techniques. Working in the fixed force ensemble facilitates the derivation of the analytical approximations, which are shown to agree well with the MCMC results. This work complements prior work on the statistical mechanics of dielectric polymers chains obtained in a different ensemble. (https://doi.org/10.1016/j.jmps.2021.104658).

Dear colleagues,
We invite you to see the preprint of our new paper "Flexoelectricity in soft elastomers and the molecular mechanisms underpinning the design and emergence of giant flexoelectricity" that will appear in PNAS. Here we present a molecular-to-continuum scale theory for the flexoelectric effect in elastomers. The theory unveils a mechanism for achieving giant flexoelectricity--which finds support in prior experimental results; it is then leveraged for designing elastomers for 1) piezoelectricity, 2) tuning the direction of flexoelectricity, and 3) flexoelectricity which is invariant with respect to spurious deformations (https://doi.org/10.1073/pnas.2102477118).

Dear colleagues,

We invite you to see the preprint of our new paper "Nonlinear statistical mechanics drives intrinsic electrostriction and volumetric torque in polymer networks" that will appear in Physical Review E. Here we use a nonlinear statistical mechanics approach to the electroelasticity of dielectric polymer chains and obtain a two-way coupling between chain deformation and dielectric response. This two-way coupling leads to electrically induced stresses and volumetric torques within an elastomer network which can be leveraged to develop higher efficiency soft actuators, electroactive materials, and novel electromechanical mechanisms. (https://doi.org/10.1103/PhysRevE.103.042504).

Dear Colleagues,

This is the preprint of an article on the design of elastomer networks for optimal electromechanical response that will appear in JMPS. We explore how various structural properties of an elastomer network (e.g. density of cross-links, fraction of loose-end monomers, orientation density of chains, etc.) affects both its bulk elastic and dielectric properties, and its performance as an actuator. (https://doi.org/10.1016/j.jmps.2020.104171).

This is the preprint of an article that will appear in Soft Matter (doi.org/10.1039/D0SM00845A)

Statistical Mechanical Analysis of the Electromechanical Coupling in an Electrically-Responsive Polymer Chain

Matthew Grasinger and Kaushik Dayal
Carnegie Mellon University

This is the preprint of an article that will appear in Computer Methods in Applied Mechanics and Engineering (https://doi.org/10.1016/j.cma.2020.112946).

Effective Response of Heterogeneous Materials using the Recursive Projection Method

Xiaoyao Peng (Carnegie Mellon University), Dhriti Nepal (Air Force Research Laboratory), Kaushik Dayal (Carnegie Mellon University)