BME Research Seminar with Dr. Alex Arzoumanidis - Challenges in Experimental Biomechanics
Bio
Dr. Alex Arzoumanidis is the president and founder of Psylotech, Inc., which produces miniature universal load frames that fill the gap between nano and macro scale testing. Leveraging microscopy and digital image correlation, these instruments enable new experimental techniques on the meso-scale. In addition to surface measurement under microscopes, Psylotech produces a rotating load train test system for CT scanners and digital volume correlation. Prior to Psylotech, Alex was at Schlumberger Doll Research in the Materials and Mechanical Sciences Group. He holds a Doctorate and Masters from the University of Texas at Austin. Alex is the chairman of the Society for Experimental Mechanics Wolfgang Knauss Young Investigator Award and chairs the Adhesion Society’s Structural Adhesives committee.
BME Seminar Series with Dr. Alex Arzoumanidis — Challenges in Experimental Biomechanics
Abstract
Mechanical testing of biological materials introduces experimental mechanics challenges, including inhomogeneous strain, low force, nonlinear viscoelasticity, and submerged samples. Digital Image Correlation (DIC) offers a full field, non-contact strain measurement compatible with microscopes already present in biological labs. However, high magnification optical microscopy is susceptible to out-of-plane motion, which can cause false dilatational DIC strains or even a complete loss of focus. A load frame is presented to minimize out-of-plane motion.
Biological tissue can also be compliant, requiring low force measurement of soft materials. The resulting low compliance load train can cause system resonance, particularly in load control. A nested control loop strategy is proposed to address this problem, specifically for cyclic loading on a rat tendon. Load cell designs are also discussed for small force measurements, such as magnetic dampening and dynamic force restoration.
A brief overview of nonlinear viscoelasticity will also be presented, including test strategies for rate dependence studies, step loadings (creep & stress relaxation), and temperature dependent failure. Spring-dashpot analogs will be compared and contrasted, as well as the importance of separating loading into dilatation and distortional contributions.
Finally, biological samples must often be submerged during mechanical testing. A horizontally loaded fluid bath designed for under microscope use is presented, featuring a submerged load cell. A confocal Raman system is also presented, as well as a vertically loaded system, where the load cell is mounted above the frame. This latter setup can handle corrosive fluids.
When: July 23rd, 12:00PM
Where: Conrad Lecture Hall, PSE 2317