research

Title: Non-uniform curvature and anisotropic deformation control wrinkling patterns on tori

The Materials Theory Group at the School of Materials Engineering of Purdue University has a post-doctoral opening in the area of modeling of thermal transport in crystalline solids. The postdoc will use Boltzmann Transport Equation approach to investigate the phonon and electron thermal transport in crystalline solids with defects. Applicants with closely related theory background in physics, materials science, mechanical engineering, or other majors are encouraged to apply. The ideal candidate is one who is strongly interested in the fundamental concepts of thermal transport and related computational modeling, and must have excellent programming skills. To apply, please send a curriculum vita with list of publications and the names and contact information of two references to Professor Anter El-Azab (aelazab@purdue.edu). The cover letter should explain the relevance of the applicant background to the postdoc research topic above. This position is part of the DOE funded Energy Frontiers Research Center for Thermal Energy Transport under Irradiation (TETI), and the postdoc is expected to collaborate with a large team of theorists and experimentalists. The position is available now and will remain open until filled.

EEO/AA Policy:

Purdue University is an EOE/AA employer. All qualified individuals, including minorities, women, individuals with disabilities, and veterans are encouraged to apply.

Department Website https://engineering.purdue.edu/MSE

Good afternoon,

We recently published a paper using VR that might be of interest:

Muhammad Omer, Lee Margetts, Mojgan Hadi Mosleh, Sam Hewitt & Muhammad Parwaiz (2019) Use of gaming technology to bring bridge inspection to the office, Structure and Infrastructure Engineering, DOI: 10.1080/15732479.2019.1615962

A. Papangelo, J. Scheibert, R. Sahli, G. Pallares, and M. Ciavarella
Phys. Rev. E 99, 053005 - https://journals.aps.org/pre/abstract/10.1103/PhysRevE.99.053005

R. Sahli, G. Pallares, A. Papangelo, M. Ciavarella, C. Ducottet, N. Ponthus, and J. Scheibert
Phys. Rev. Lett. 122, 214301 – https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.122.214301

Check out our latest publication on porcine liver biomechanics under high strain rate conditions -

"Mechanical Response of Porcine Liver Tissue under High Strain Rate Compression", Bioengineering, 2019, 6(2), 49; https://doi.org/10.3390/bioengineering6020049

https://www.mdpi.com/2306-5354/6/2/49

W. Xia et al., Science Advances (2019), https://advances.sciencemag.org/content/5/4/eaav4683?utm_source=TrendMD&...

Preprint here: https://www.researchgate.net/publication/333090377_A_Novel_Hybrid_Finite...

Shape memory ceramics, such as yttria-stabilized tetragonal zirconia (YSTZ), offer unique properties including ultra-high operating temperatures and high resistance to oxidation. However, they are susceptible to formation of defects during manufacturing and/or by mechanical deformation. To completely take advantage of their shape memory properties, it is necessary to fully understand the nano-structural evolution of defects under external stimuli. In this study, defect evolution behaviors in YSTZ nanopillars are investigated by atomistic simulations.

We studied the oxidation behavior of face-centered cubic Al0.3CoCrCuFeNi high entropy alloy through first-principles calculations. Three surface orientations were chosen for oxidation, and all the possible combinations of atomic positions at these surfaces were considered. The adsorption energy of oxygen adhesion to the studied surfaces was the lowest for the sites with more neighboring Cr atoms, and the second most favorite site for oxygen adsorption had more neighboring Al atoms.

Link to our new paper outlining some strategies to steer interfacial debonding to a desired interface during a demolding process when the two interfaces in a 3-layer structure are equally weak. The article can be downloaded for free until July 5th. Would sincerely appreciate any feedback.

https://authors.elsevier.com/a/1Z3d04kE0IsZs

Abstract:

A Cosserat rod based continuum approach is presented to obtain phonon dispersion curves of flexural, torsional, longitudinal, shearing and radial breathing modes in chiral nanorods and nanotubes. Upon substituting the continuum wave form in the linearized dynamic equations of stretched and twisted Cosserat rods, we obtain analytical expression of a coefficient matrix (in terms of the rod's stiffnesses, induced axial force and twisting moment) whose eigenvalues and eigenvectors give us frequencies and mode shapes, respectively, for each of the above phonon modes.

Preprint here: https://www.researchgate.net/publication/333260238_An_Adaptive_Quasi-Con...

https://doi.org/10.1016/j.actamat.2019.05.030

Abstract

We have discovered a peculiar form of fracture that occurs in a highly stretchable silicone elastomer (Smooth-On Ecoflex 00–30). Under certain conditions, cracks propagate in a direction perpendicular to the initial pre-cut and in the direction of the applied load. In other words, the crack deviates from the standard trajectory and instead propagates perpendicular to that trajectory. The crack arrests stably, and thus the material ahead of the crack front continues to sustain load, thereby enabling enormous stretchabilities. We call this phenomenon 'sideways' and stable cracking.

ACS Nano (2019), in press (https://pubs.acs.org/doi/10.1021/acsnano.9b01794).

Shuze Zhu, Pascal Pochet, and Harley T. Johnson

Materials Today (2019), in press (https://doi.org/10.1016/j.mattod.2019.03.016).

Yubing Zhou, Chaoji Chen, Shuze Zhu, Chao Sui, Chao Wang, Yudi Kuang, Upamanyu Ray, Dapeng Liu, Alexandra Brozena, Ulrich H.Leiste, Nelson Quispe, Hua Guo, Azhar Vellore, Hugh A. Bruck, Ashlie Martini, Bob Foster, Jun Lou, Teng Li, Liangbing Hu

A recent study has drawn a new aspect on the role played by the surface stress with a torsional profile on silicon nanowires to address the existing controversy from experimental and computational studies (https://www.researchgate.net/publication/327768951_Surface_Stress_Effect...).

This paper aims at assessing the influence of environmental parameters on the modal characteristics of age-old masonry constructions. The results of a long-term ambient vibration monitoring of the San Frediano bell tower in Lucca (Italy) are reported. The tower, dating back to the 11th century, has been fitted along its height with four triaxial seismometric stations, which were left active for about one year.

https://doi.org/10.1016/j.engstruct.2017.10.045

Enjoy !

Journal Club for May 2019: Using Instabilities to Control Soft Robots Philipp Rothemund University of Colorado Boulder

One Ph.D. position is now available starting October 2019 (and open until filled) on the experimental and theoretical study of thin polymeric nanofilms. The PhD will be pursued in the Solid Mechanics Laboratory of Ecole Polytechnique, Paris, France in collaboration with BD Medical Pharmaceutical Systems (Grenoble, France). The potential student will work on the development of new experimental procedures and theoretical models to understand the formation and mechanical response of thin polymer films over soft polymer substrates.

Dear imechanicians

I hope that this paper is of interest to you. The phase field fracture code developed in FEniCS is available at www.empaneda.com/codes

Phase field modelling of crack propagation in functionally graded materials

Hirshikesh, S. Natarajana, R.K. Annabattula, E. Martínez-Pañeda

Composites Part B: Engineering 169, pp 239-248 (2019)