research

Mechanical performance of silicon nanopillars with homogeneous and gradient nanotwinned structures are investigated through a series of molecular dynamics simulations. The most observed Σ3 twin boundary (TB) with two preferable (lowest surface energy) planes of {111} and {001} are used to generate homogeneous and gradient nanotwinned structures. Simulations of compression and tension of nanotwinned pillars reveal an extra strengthening behavior due to the addition of Σ3 TBs when compared to the single crystalline nanopillar without any TBs.

Keep EML Webinar going by donating at: 

https://www.gofundme.com/f/keep-eml-webinar-going

We gratefully acknowledge the financial support for Season 2 of EML Webinar by (as of 18 May 2021):

Denian Zhuang, Jimmy Hsia, Zhigang Suo, Ruobing Bai, Teng Li, Liqing Jiao, Shengqiang Cai, Grace Gu, Xin Wen, Jianyu Li, Jin Yang, Nitesh Arora, and anonymous donors. 

EML Webinar (Season 2) on 19 May 2021 will be given by Eduard Arzt, Saarland University. Designing with gaps – functional surfaces for sustainable gripping. Discussion Leaders: Huajian Gao, Nanyang Technological University

Time: 10 am Boston, 3 pm London, 10 pm Beijing on 19 May 2021

The plant cell wall possesses an unusual combination of strength and ability to expand without weakening or breaking (a quality required for plant growth), but the molecular basis for these traits has long been unclear. In a collaborative study led by Prof. Sulin Zhang and Prof.

In this work published in PNAS (https://www.pnas.org/content/118/19/e2100077118), we present compliant 3D frameworks that incorporate microscale strain sensors for high-sensitivity measurements of contractile forces of engineered optogenetic muscle tissue rings, supported by quantitative simulations.

Abstract: 

Ares Rosakis and collaborators across three other institute have just published a fascinating account of a rather unexpected mechanism for generating  tsunamis. The paper, published in PNAS, is attached with this post.

The associated press-release provides a compelling lay-person summary: https://www.caltech.edu/about/news/contrary-to-previous-belief-strike-sl...

We revisit Nye's lattice curvature tensor in the light of Cartan's moving frames. Nye's definition of lattice curvature is based on the assumption that the dislocated body is stress-free, and therefore, it makes sense only for zero-stress (impotent) dislocation distributions. Motivated by the works of Bilby and others, Nye's construction is extended to arbitrary dislocation distributions. We provide a material definition of the lattice curvature in the form of a triplet of vectors, that are obtained from the material covariant derivative of the lattice frame along its integral curves.

In this paper we investigate the possibility of elastodynamic transformation cloaking in bodies made of non-centrosymmetric gradient solids. The goal of transformation cloaking is to hide a hole from elastic disturbances in the sense that the mechanical response of a homogeneous and isotropic body with a hole covered by a cloak would be identical to that of the corresponding homogeneous and isotropic body outside the cloak.

Jiao, S., & Liu, M. (2021). Snap-through in Graphene Nanochannels: With Application to Fluidic Control. ACS Appl. Mater. Interfaces, 13, 1158–1168.

Liu, M., Gomez, M., & Vella, D. (2021). Delayed bifurcation in elastic snap-through instabilities. J Mech. Phys. Solids, 151, 104386.

Mutian Hua, Shuwang Wu, Ximin He

Bioinspired Soft Materials Group

University of California, Los Angeles

Introduction

We recently proposed a method that uses distance fields to exactly impose boundary conditions in physics-informed neural networks (PINN).  This contribution is available as an arXiv preprint.

Dear iMechanica colleagues, I am pleased to share with you our newest paper on qauntitative prediction of rapid solidification. S. Kavousi, B. Novak, D. Moldovan, and M. Asle Zaeem. Quantitative prediction of rapid solidification by integrated atomistic and phase-field modeling.

Abstract

Our team led by Professor Tomasz Wierzbicki at MIT Mechanical Engineering is looking for a highly motivated Postdoctoral Associate in the area of machine learning for solid-state batteries. The candidate is expected to develop machine-learning-based computational tools for the characterization of the interfacial failure in Li-metal all-solid-state batteries. Candidates who have experience in physics-informed machine learning, computational and solid mechanics, multiphysics modeling, and all-solid-state batteries are encouraged to apply by sending a CV to Dr.

On April 27th we will present a webinar hosted by our partner @Altair where we will share efficient high-fidelity design and optimization of composite blades using VABS. Register now at https://bit.ly/3gnQJAN

Electron beam melting (EBM) is a metal powder bed fusion additive manufacturing (AM) technology that is widely used for making three-dimensional (3D) objects by adding materials layer by layer. EBM is a very complex thermal process which involves several physical phenomena such as moving heat source, material state change, and material deposition. Conventionally, these phenomena are implemented using in-house codes or embedding some user subroutines in commonly used commercial software packages, like Abaqus, which generally requires considerable expertise.

Our latest article on the ballistic performance of polymer/metal nanostructures is freely available for 50 days from today: https://authors.elsevier.com/a/1cy9c3In-urcWx

cdmHUB invites you to attend the Global Composites Experts Webinar Series. 

Title: Rheology of Carbon Fiber Thermoplastic Polymer Composites

Speaker: Dr.  R. Byron Pipes

Time: 4/22, 11AM-12PM EST.

Please go to https://www.purdue.edu/cmsc/events/2020-webinars/ to register for this webinar.