Congratulations: Gabriel Smith – Scientific Image Contest
Gabriel Smith, a LEAP student in ME@BU working in the MOSS lab won third place in the 2015 Mechanical Engineering Scientific Image Contest.
NEW.Mech 2015 @ BU
NEW.Mech is a one-day workshop that aims to bring together the New England Mechanics community with an interest in exploring new directions on the mechanics of materials and structures and share the latest advancements in the field.
The workshop will be located at Boston University on October 3rd. As in other other years, there will be a poster session, among which a subset will be chosen for short (3 minute) talks with limited time for questions. In addition, there will be a “Gallery of Mechanics” to showcase the most visually striking movies and images from your research.
More information to follow at: https://www.bu.edu/moss/newmech2015/
Congratulations: Behrouz Tavakol Defends his Dissertation
Dr. Behrouz Tavakol successfully defended his dissertation entitled, "Buckling at the Fluid - Soft Solid Interface: A Means for Advanced Functionality within Soft Materials". Upon his defense, he was award his Doctorate in Engineering Mechanics from Virginia Tech. Congratulations to Behrouz!
Paper: Growing Sheets into Shells in Soft Matter
Our manuscript entitled “Morphing of geometric composites via residual swelling” has been published in the Soft Matter. This work was authored by Matteo Pezzulla, and co-authored by Steven Shillig, Paola Nardinocchi, and Douglas Holmes.
This work was also highlighted on Soft Matter's inside cover:
Understanding and controlling the shape of thin, soft objects has been the focus of significant research efforts among physicists, biologists, and engineers in the last decade. These studies aim to utilize advanced materials in novel, adaptive ways such as fabricating smart actuators or mimicking living tissues. Here, we present the controlled growth-like morphing of 2D sheets into 3D shapes by preparing geometric composite structures that deform by residual swelling. The morphing of these geometric composites is dictated by both swelling and geometry, with diffusion controlling the swelling-induced actuation, and geometric confinement dictating the structure’s deformed shape. Building on a simple mechanical analog, we present an analytical model that quantitatively describes how the Gaussian and mean curvatures of a thin disk are affected by the interplay among geometry, mechanics, and swelling. This model is in excellent agreement with our experiments and numerics. We show that the dynamics of residual swelling is dictated by a competition between two characteristic diffusive length scales governed by geometry. Our results provide the first 2D analog of Timoshenko’s classical formula for the thermal bending of bimetallic beams – our generalization explains how the Gaussian curvature of a 2D geometric composite is affected by geometry and elasticity. The understanding conferred by these results suggests that the controlled shaping of geometric composites may provide a simple complement to traditional manufacturing techniques.
Our latest paper on growing sheets into shells was published in @softmatter (http://t.co/IxekMNma84). Made the inside cover too! #NSFfunded
— Douglas Holmes (@dpholmes) July 17, 2015
Paper: Falling Slinkys in JSV
Our manuscript entitled "Falling vertical chain of oscillators, including collisions, damping, and pretensioning" has been published in the Journal of Sound and Vibration. This work was authored by Raymond Plaut, and co-authored by Andy Borum, Douglas Holmes, and David Dillard.
A recent topic of interest has been the “levitating Slinky”. The Slinky spring is held at its top and hangs in a vertical equilibrium configuration. The top is then released and the Slinky falls downward. During an initial period of time, the bottom of the Slinky does not move. A similar phenomenon occurs if an elastic bar is held at its top and then released. Such a falling Slinky can be modeled by a discrete set of rigid masses, each one representing a coil (turn). The masses in the model are connected by massless springs, and also by dashpots if internal damping is not negligible. As for adjacent coils of a Slinky, adjacent masses of the model cannot penetrate each other, which introduces geometrical constraints on the system.
A chain of point masses connected by linear springs and sometimes dashpots is considered. The chain hangs in a vertical equilibrium configuration, held by its top mass. Then the top mass is released, and the chain falls. Internal damping, modeled by the dashpots, causes the bottom mass to move faster. As the system falls, upper masses sometimes accelerate faster than gravitational acceleration, and collisions may occur between adjacent masses. The types of collisions treated here include elastic, inelastic, and perfectly inelastic (in which colliding masses often stick together thereafter). The unstretched lengths of the springs, and a compressive force caused by pretensioning, may significantly affect the characteristics of the motion. Analytical and numerical results are presented for cases involving a few masses, and some generalizations are made for systems with an arbitrary number of masses. Also, the vertical chain may be used to model the motion of a falling Slinky after release at its top end. The bottom of the continuous Slinky does not move until the coils above it have collapsed onto it, and the collapse time is estimated here using the discrete chain model. For a metal Slinky with 86 masses, the estimated time is close to that previously obtained by a continuous elastic analysis.
MOSS@UCSB
Seminar: UCSB - Mechanical Engineering: Morphing of Slender Structures by Swelling – Prof. Douglas P. Holmes
May 4th, 2015
https://me.ucsb.edu/events/me-seminar-morphing-slender-structures-swelling
MOSS@NIST
Seminar: National Institute for Standards and Technology - Polymers Division: Morphing of Slender Structures by Swelling – Prof. Douglas P. Holmes
April 24th, 2015
News – NSF CAREER Award
NSF Engineering:
Class of 2015 Early Career Engineers to Watch
NSF Engineering boosts 146 early-career researchers with awards totaling $73M
@NSF @NSF_ENG Research towards smart needles & autonomous structures begins with a buried elastica #CAREER pic.twitter.com/wt4NLsn63l
— Douglas Holmes (@dpholmes) March 25, 2015
BU College of Engineering News:
Newest ME Faculty Member Receives NSF CAREER Award - by Mark Dwortzan
Bostonia:
Thin Rods Study Wins NSF Grant
MOSS@APS March Meeting
The MOSS group presented research led by Matteo Pezzulla of Sapienz Universita di Roma on the "Morphing and Snapping of Plates and Shells via Swelling" at the APS March Meeting. Prof. Holmes organized and chaired a Focus Session entitled "Extreme Mechanics: Snapping, Jumping and Popping" with an Invited Talk by Dennis Kochmann of Caltech entitled "About snapping structures and phase transformations".
MOSS@Adhesion Society
The MOSS lab presented research by Anupam Pandey, done in collaboration with Suzie Protière, at the 2015 Annual Meeting of the Adhesion Society in Savannah, GA. The talk was entitled "Elastocapillary Rise Between Swellable Beams", and was presented in the “Soft III: Mechanics” track (More details)
