Biological Materials Science: Bioenabled Materials
Sponsored by: TMS Functional Materials Division, TMS Structural Materials Division, TMS: Biomaterials Committee
Program Organizers: Steven Naleway, University of Utah; Jing Du, Pennsylvania State University; Rajendra Kasinath, DePuy Synthes (Johnson and Johnson); David Restrepo, University of Texas at San Antonio
Wednesday 2:00 PM
February 26, 2020
Room: Leucadia
Location: Marriott Marquis Hotel
Session Chair: Claire Acevedo, University of Utah; Rajendra Kasinath, DePuy Synthes (Johnson and Johnson); Isaac Nelson, Sandia National Laboratory
2:00 PM
Biomimetic Design Principles for Honeycomb Design: A Comparative Study of Honeybee and Wasp Nest Geometry: Derek Goss1; Clint Penick2; Alex Grishin3; Sridhar Niverty1; Dhruv Bhate1; Nikhilesh Chawla1; 1Arizona State University; 2Kennesaw State University; 3Phoenix Analysis & Design Technologies, Inc.
The hexagonal honeycomb has been an object of interest for over two millennia, and it is one of the most direct forms of biomimetic design today. The hexagon is, however, not unique to the European honeybee, and is a shape that appears in insect nests of other bees and wasps. There is little research that compares the geometry of these nests, which is the primary objective of this work. Insect nests from over 70 different species were obtained and scanned using structured white light microscopy. Three metrics: cell diameter, wall thickness, and corner radius, were measured for each of these nests, and the resulting data analyzed for trends. Environmental and phylogenetic factors were also studied. Analytical models derived from beam theory, Finite Element Analysis, and experimental testing, were leveraged to help interpret the observed results, and suggest biomimetic principles for use in future honeycomb design for engineering applications.
2:20 PM Cancelled
Hierarchical Architecture in Jamming Technology for Soft Robotics: Albert Matsushita1; Luis Garcia1; Zida Liu1; Jennifer Doan1; Joanna McKittrick1; 1University of California, San Diego
Jamming (the evacuation of loose media in an air-tight membrane to generate stiffness) is a well-established technology in the soft-robotics field that often cites bio-inspiration. However, the concept of hierarchical architecture common to biological materials has yet to be applied. Here it is shown how considering the hierarchical structure of a jammer at the jamming media (primary level), the organization of jamming media (secondary level), and the organization of jammers (tertiary level) can offer new functionalities not yet demonstrated by conventional jamming technology. Improved stiffness and strength per unit weight, isotropy and anisotropy control, mechanical property gradients, and other features promise new application spaces for jamming in orthopedics,protective wear, and more robust soft robots..
2:40 PM
Characterization of Soft Actuation Through Ultrasonic Atomization: Han-Joo Lee1; Kenneth Loh1; 1University of California, San Diego
Most biological systems fully take advantage of their soft tissues by quickly reacting and interacting with the environment. This exceptional performance is possible due to flexible muscles that can bend and contract in multiple degrees-of-freedom. Since traditional robots with rigid components cannot mimic these movements, soft robotic systems fabricated from flexible elastomers are starting to receive much attention. Similarly, developing actuation techniques that can control the movement of these soft materials in multiple degrees-of-freedom is also crucial. This study proposes a new soft actuation mechanism through the use of ultrasonic atomization and small piezoelectric transducers. Unlike conventional pneumatic-based systems, this soft structure is completely untethered, which can be actuated by simply placing it above an ultrasonic transducer. First, a hollow structure was fabricated by pouring uncured elastomer into a 3D-printed mold. Second, the structure was partially filled with a small amount of liquid and placed above a piezoelectric disc. Then, exciting the transducer generated ultrasonic waves that propagated through the wall of the structure. When the amplitude of the ultrasonic wave was high enough, the liquid inside the structure was atomized and ejected small droplets inside the closed, soft chamber. These droplets rapidly evaporated and deformed the soft structure. In this work, the experimental results were compared with finite element modeling to characterize the ultrasonic-atomization-induced soft structure actuation.
3:00 PM
Microstructure and Nanomechanical Properties of the Ironclad Beetle’s Exoskeleton: Nayeon Lee1; Vina Nguyen1; Parker Berthelson1; Robert Moser2; Raj Prabhu1; 1Mississippi State University; 2Engineer Research and Development Center
This study examined the structural design of natural composites within the exoskeleton of the Southwestern Ironclad Beetle known for its exceedingly hard cuticle. The Ironclad beetle’s exoskeleton is primarily composed of chitin fibers and protein, and organized into four layers; epicuticle, exocuticle, endocuticle, and epidermis. Structural and nanomechanical analyses revealed that each layer had distinctive function and was joined as functional gradient materials. The epicuticle was comprised of waxy and polygonal walls (~2 µm in diameter) functioning as a waterproof and anti-adhesive to inhibit microbial contamination. The exocuticle showed the highest Young’s modulus (~15 GPa) providing high strength properties. The endocuticle’s modulus was lesser (8~10 GPa). However, it gives resilience and toughness to the exoskeleton with fibrous stacking layers, knowns as Bouligand structures. Lastly, the modulus of the epidermis was 2~3 GPa to allow the attachment of muscle and soft tissue. These findings can be applied to design composite materials.
3:20 PM
Active Metamaterial Skins for Friction Coefficient Control: Yujin Park1; Kenneth Loh1; 1University of California, San Diego
Nature is ripe with biological organisms that possess unique capabilities of changing their skin for various purposes. Many attempts have been made to optimize artificial surfaces to increase or decrease friction depending on operational needs. This study introduces an innovative “active skin” based on mechanical metamaterials that harvest instabilities in order to exploit unusual properties. In its pristine state, the surface properties of flat active skins are governed by its intrinsic material properties. When strained, each of the architected units undergo out-of-plane deformations that drastically change its surface characteristics (i.e., friction). Notches are introduced at judicious locations to control the buckling orientation of each unit cell that plays an important role in the active skin’s surface friction properties. Thus, based on the idea of harvesting structural instabilities, this study introduces a reversible, reconfigurable, active skin that features programmable 3D deformations.
3:40 PM Break
3:55 PM
Electrochemical Studies of Titanium Alloys for Dental Implants: Jaewan Bae1; Jacob Benoun1; Vilupanur Ravi1; 1Cal Poly Pomona
TNZ is a new class of beta-phase titanium alloys, which have a lower elastic moduli, as compared toconventional Ti-6Al-4V (Ti64), thereby minimizing stress shielding in metallic implants. These alloys also have non-toxic constituents. Low levels of boron additions (< 0.04 wt.%) increase the mechanical strength and improve the corrosion behavior of Ti64 alloys. In this study, the corrosion behavior of Ti-28Nb-20Zr, Ti-39Nb-6Zr, Ti-6Al-4V-0.01B and Ti-6Al-4V-0.04B were compared to Ti64 in phosphate buffered saline solution (PBS) and Fusayama artificial saliva solution at 37℃. Cyclic polarization tests were used to evaluate the corrosion susceptibility of the titanium alloys to serve as implant devices. Linear polarization resistance measurements, Tafel plots, electrochemical impedance spectroscopy (EIS) measurements and scanning electrochemical microscopy (SECM) were conducted to obtain deeper insights into corrosion behavior and surface passivation. Preliminary results in PBS show that these alloys are expected to corrode at lower rates.
4:15 PM
Biocorrosion and Biocompatibility of Advanced Titanium Alloys: Vilupanur Ravi1; 1California State Polytechnic University, Pomona
One of the impediments to the durability of prosthetics is their loosening over time. This process, known as aseptic loosening, is brought about by the inflammatory response against the prosthetic metal. The resulting activation of osteoclasts leads to bone loss around the implant, thereby loosening it and necessitating prosthetic replacement. Mitigation of this problem, e.g., by the development of novel implant alloys, would be a welcome development. In this presentation the development of a new class of titanium alloys containing boron will be traced. The boron additions have significant effects on their microstructures and mechanical properties. Understanding the effect of this alloying addition on corrosion resistance is equally important for predicting longevity in inside the human body. Some aspects of the mechanical behavior of these alloys and their corrosion resistance in physiologically relevant environments will be discussed.
4:35 PM
Measurement of Moisture-dependent Ion Diffusion Constants in Wood Cell Wall Layers Using Time-lapse Micro X-ray Fluorescence Microscopy: Joseph Jakes1; Samuel Zelinka1; Christopher Hunt1; Peter Ciesielski2; Charles Frihart1; Danielle Yelle1; Leandro Passarini1; Sophie-Charlotte Gleber3; David Vine3; Stefan Vogt3; 1USDA FS Forest Products Laboratory; 2National Renewable Energy Laboratory; 3Advanced Photon Source, Argonne National Laboratory
The diffusion of chemicals and inorganic ions through wood cell walls is a critical process in nearly all woody biomass applications, including biorefineries, wood-based building materials, green electronics, and even as bioinspiration for new smart materials. Despite the near ubiquitous importance of intra-cell wall diffusion, the poorly understood diffusion mechanisms and rates are hindering progress. In this work, a new experimental methodology utilizing synchrotron-based X-ray fluorescence microscopy (XFM) is developed to provide the needed quantification of diffusion rates through wood cell walls. The results also improve the understanding of diffusion mechanisms. With these new insights, researchers can now utilize polymer science approaches to engineer the molecular architecture of lignocellulosic biomass to optimize properties for specific end uses. Additionally, our newly developed XFM-based approach could be adapted to study diffusion in the micron-scale features of other types of biological materials.
4:55 PM
Phase Stability and Mechanical Properties of the Metastable Beta Ti Alloys with High Oxygen Content and Various Amount of Several Beta Stabilizing Elements: Eliska Jaca1; Josef Strasky1; Jiri Kozlik1; Tereza Kretkova1; Lucie Bodnarova2; Michaela Janovska2; Milos Janecek1; 1Charles University; 2Czech Academy of Sciences
Beta Ti alloys are considered as perspective materials for the new generation of body implants. Their strength can be substantially improved by addition of interstitial oxygen to fit the requirements for implant materials. By adding 0.7 wt.% of oxygen, the yield strength of 1000 MPa can be achieved in the quenched condition while the ductility of approx. 20% is obtained. The Young’s modulus close to that of a bone (10-30 GPa) is preferred to avoid the so-called stress-shielding effect. To achieve this reduction of Young’s modulus, several Ti-Nb-Zr-O based alloys with identical content of Zr (7 %) and O (0.7 %) and various content of Nb, Ta and Fe were produced and studied thoroughly. It was found, that Young’s modulus drops with lower beta phase stability (i.e. lower amount of Nb, Fe, Ta) and e.g. Ti-29Nb-7Zr-0.7O alloy exhibits Young’s modulus of 60 GPa while the yield strength reaches 1000 MPa.