1. Vibration-based Fatigue Testing
In current and next-generation aerospace vehicles, structural components are subject to extreme temperatures and fluctuating loads, such as those encountered in gas turbine engines and along leading edges in hypersonic flight. Thus, to ensure the safety, reliability, and performance of the vehicle, structural materials must be characterized to withstand extreme temperature fatigue. The Air Force Research Lab (AFRL) uses a vibration-based method in which they excite a square plate in resonance, thereby accumulating many load cycles very quickly.
1.a. Miniaturization of Vibration-based Fatigue Specimens
In its current state, one key limitation of the technique is that the vibrating plate is much too large to fit within the scanning electron microscope (SEM) at USU's Microscopy Core Facility (MCF). As fatigue damage initiates at the micro-scale, the overly large plates cannot be examined micro-structurally until the completion of a fatigue test, meaning we cannot compare failed specimens against their pristine state prior to testing.

In this research, you will first assist one of my PhD students in performing vibration experiments to validate his shape optimization simulations.  You will then repeat and re-validate his simulations at a smaller length scale to develop miniaturized plates, thus enabling better micro-structural characterization before and after fatigue testing.
Photo of AFRL's vibration-based test setup
1.b. Relative Uncertainties of Motion Blur vs. Depth of Field
Our lab uses camera-based measurements to monitor the deformation of the plates.  In the vibration-based method, the parts of the plate which move fastest (and are thus most susceptible to motion blur) also move the most out-of-plane (and are thus susceptible to poor depth of field). 

In this research, you will de-couple these sources of error by comparing a sequence of three measurements: (1) Out-of-plane quasi-static rigid-body motion, thus isolating poor depth of field while eliminating motion blur; (2) In-plane rigid-body rotation, thus isolating motion blur while eliminating out-of-plane motion; and (3) Out-of-plane vibration, which contains both sources of error.
Simulation of the plate's resonant mode showing stress (left) and out of plane displacement (right)
1.c. Custom UV Light Source for Extreme Temperature Imaging
Generally speaking, our camera measurements should be performed using as bright a light source as is safely available.  This allows shorter exposure times on the cameras (to reduce motion blur) and smaller apertures on the lenses (to improve depth-of-field), both of which otherwise result in much darker images.  At extreme temperatures, the measurements must also be performed using ultraviolet (UV) lights, cameras, lenses, and filters to mitigate the light emitted by objects when they glow white-hot.

In this research, you will identify and then cannibalize a tanning bed to use as a UV light source.  We will then implement the light source to record deformation during extreme temperature testing.
Images of a specimen surface under various temperatures and lighting. The UV images remain visible at temperatures well above which the others have saturated.
2. Micromechanics-Informed Models of Knitted Metamaterials
Woven fibers are a mainstay of fiber composites, but compared to woven fabrics, knits are considerably stretchier and can absorb higher impact. Knits get these properties from the ordered combinations of stitches (knits and purls) from which they are patterned. Similarly, the microstructures of metallic alloys are composed of ordered lattices. Such alloys can be strengthened to improve mechanical performance by introducing defects into the lattice that act as obstacles against deformation.  Analogous "defects" can be found in knitting: for example, slipped stitches may be comparable to vacancies in a lattice; increases or decreases may be comparable to edge dislocations; and seams may be comparable to grain or phase boundaries.  By manipulating stitch patterns, composites manufacturers can potentially tailor new emergent behaviors to achieve more favorable mechanical performance.

In this project, you will first assemble a test fixture to apply force to a swatch of knitted fabric.  We will then use camera-based deformation measurements to assess how load distributes through the fabric, and compare how the distributions change in the presence of defects. The results of this work will be published in a series of journal articles in peer-reviewed scientific literature.
Select "lattice structures" observed in knitting. Left to right: (i) stockinette stitch (knit side); (ii) stockinette stitch (purl side); (iii) 1-1 ribbing; (iv) garter stitch; (v) seed stitch.
Select "defects" observed in knitting. Left to right: (i) slipped stitch; (ii) an increase followed immediately by a decrease; (iii) a purl substituted for a knit; (iv) additional rows via short-row shaping; (v) an additional column via an increase followed a few rows later by a decrease; (vi) a seam between two knit panels; and (vii) a "grain boundary" between two mismatched regions of ribbing.
3. The Metallurgy of Marvel: Teaching Scientific Literature Review through Superhero Comics
(This post contains spoilers for the past 30+ years of X-Men comics)
 
In this research, you will formulate a research question to then answer through literature review of superhero comics.  For example: in 1992, during the Fatal Attractions crossover event, Magneto forcibly removed the adamantium from Wolverine's skeleton.  Then in 1999, during the lead-up to The Twelve, Apocalypse brainwashed Wolverine and reintroduced adamantium into his skeleton.  Was this the same alloy that was originally implanted by the Weapon X program in the late 80's?  Do the alloys exhibit different material properties based on how they are described in the literature?  Does Laura Kinney (X-23) have the same alloy?  You will then write a research paper describing your findings to Superhero Science and Technology, a peer-reviewed scientific journal (though admittedly not a high-impact one).
 
The purpose of this project is to identify best practices to promote undergraduate journal authorship, and more specifically how to conduct a literature review. As you answer your research question, keep notes on how you identified the most relevant sources and what information you gleaned from them. In parallel with your above research paper, you will compile guidelines which will help streamline paper-writing in the PI’s own research group. These guidelines will be presented through an appropriate venue such as the annual meeting of the American Society for Engineering Education (ASEE), or through a second paper to be submitted to the Journal of Engineering Education or a similar journal.
 
NOTE: I can't justify paying you to read comics on any of my current grants, so this project is only intended for participants in USU’s URF program.  That way you at least get some payment via your URF stipend.  If you want help applying for more funds through the URCO program, I’ll help you prepare that application too.

General Applicants

The Mechanics at Extreme Temperatures Lab is always looking for qualified students at the Undergraduate, Masters, and PhD levels. Contact Dr. Berke to see what topics best fit with your career goals and research interests.  Women and underrepresented minorities in engineering are especially encouraged to apply.

The following positions are all currently available:

Graduate Research Assistants

No specific openings at this time, but please contact Dr. Berke to discuss your research interests.

Qualifications
  • B.S. in Mechanical Engineering or a closely-related field
  • Demonstrated interest in a research career in experimental solid mechanics
  • PhD students are preferred, but Plan-A M.S. students will also be considered. (You do not need an M.S. to pursue a PhD.)

Undergraduate Research Assistants

Please contact Dr. Berke to discuss your research interests.  If he cannot accommodate you directly, Dr. Berke is always willing to assist with EURP and URCO applications or recommend other labs.

Qualifications
  • Must be currently enrolled in MAE or a related field.
  • Good communication skills.
  • Work well in teams.
  • Available 5-10 hours/week during the semester, more during the summer.

Undergraduate Teaching Assistants

No positions available at this time.

NOTE: As many of the materials studied by our lab are nuclear or defense related, U.S. citizens and permanent residents are often preferred but not required.

To apply, please send a resume/CV and a brief statement of your career goals and research interests to [email protected].  You may also be asked to provide references, a transcript, and/or a writing sample.

Helpful Links

Undergraduate Resources
Graduate Resources
NOTE: Although due dates may vary, most of the above programs are available yearly. Check the official websites for the most up to date information.

Most graduate fellowships are only available to graduating seniors or to applicants in their first year of grad school.