School of Civil and Environmental Engineering
Ph.D. Thesis Defense Announcement
Angelwing Bivalve Inspired Rock Drilling
By Yumeng Zhao
Advisor:
Dr. Sheng Dai (CEE)
Committee Members: Dr. Chloe Arson (Cornell U./ GT CEE), Dr. Saad Bhamla (ChBE), Dr. Douglas Cortes (New Mexico State U.), Dr J. David Frost (CEE)
Date and Time: Wednesday, Feburary 21st, 2024, 11:00 AM - 1:00 PM
Location: Mason 2119
Drilling in rock plays a pivotal role in resource exploitation and recovery, infrastructure construction, geo-hazards safeguard and rescue, environment protection, and scientific exploration in deep underground, marine, or even extraterrestrial environments. Over the past hundred years, the advent of advanced technologies for hard rock drilling and excavation has significantly contributed to the formulation of powerful and cost-effective methodologies. These methodologies have proven instrumental in oil and gas recovery, mining, tunnels/utility/sewage/water supply systems construction, nuclear disposal, and geological carbon sequestration, to name a few. To further improve the drilling technology, more durable drill bits, enhanced penetration rates, and heightened autonomy are desired, all of which collectively serve to improve efficiency, mitigate costs and bolster safety measures.
This project delves into the mechanisms employed by angelwing clam (Cyrtopleura costata) as they bore into various rocks, with the objective of devising innovative solutions for efficient rock drilling. The work starts with a comparison of a variety of drilling strategies in nature with man-made field and lab drilling techniques and found angelwing clam adopts highly energy-efficient drilling. By expressing the shell morphology with mathematical formulations and characterizing individual denticle cutting angles, the advantages of angelwing shell and denticle morphology are revealed. Mechanical testing on angelwing shell by nanoindentation and microscopic image analysis on shell structures concludes that the shell is made of hard aragonite and the unique micro-structural patterns are believed to protect the shell from damage. Inspired by the collective cutting by numerous denticles on angelwing shells, numerical simulations on the synergy effect in rock cuttings emphasize the importance of cutter shape, spacing, lag and substrate material properties on cutting response, especially the fragmentation process. Further 3D printed drill bit prototype experiments compared the cutting performance of drill bits with different geometry in terms of cutter back rake angles and orientations.
This research unravels the underlying mechanics of angelwing rock cutting and provides bio-inspirations for drilling technologies targeting drilling at higher efficiency, greater depths, lower cost, and more adaptability.