CASE STUDY
Measuring Trap-Jaw Ant Mandible Energy With OAV Air Bearings.
Duke University researchers built a pendulum-based measurement system using OAV Air Bearings to capture the true energy of a trap-jaw ant's strike with an unprecedented accuracy.
CUSTOMER
Duke University
INDUSTRY
Research & Academics
APPLICATION
Energy Measurement
PRODUCT USED
Roller Air Bearing
BENEFIT
Precision Testing
THE CHALLENGE
OAV founder Murat Erturk’s favorite expression, “outside the box", is appropriately associated with the company Murat started after his engineering career in aerospace and aviation related technologies. Indeed, many of OAV’s engineers focus on thinking “outside the box” when speaking with clients and customers or when developing new air bearings to solve existing manufacturing and industry wide problems. In much the same way that LED technology has come to replace incandescent light bulbs, frictionless air bearings are rapidly replacing standard roller and linear bearings, thanks not only to the industry’s need for greater efficiency and energy reduction, but also due to the need for greater precision and long-term cost savings.
Figure 1. High-speed imaging of a trap-jaw ant used to analyze mandible strike dynamics.
Justin Jorge, a PhD student in the laboratory of Dr. Sheila Patek at Duke University, was recently tasked with measuring the energy released from the mandibles of an ant, the trap-jaw ant to be precise. Jorge realized that the current sensors and energy measurement techniques did not work at the size and time scales of a trap-jaw ant mandible strike and set out to create a novel pendulum-based measurement system. After an extended period of design and testing, Jorge came to the conclusion that conventional techniques for creating a pendulum (including a pendulum-based measurement system utilizing existing roller bearings) for accurately measuring the energy released from the mandibles were grossly insufficient and inaccurate.
Indeed, any attempts at a measurement was made exceedingly difficult due to the size, speed, and acceleration of the trap-jaw ant’s mandibles – an understandable conclusion given the tips of the mandibles accelerate at a speed greater than a bullet fired from a common handgun. The energy generated by the mandibles on their target could not be accurately determined through the use of common technologies using standard methods with a common rotational bearing. Data taken was compromised by the energy required to overcome initial friction and moment of inertia of the traditional bearings in earlier designs of the test assembly.
THE SOLUTION
Working in Dr. Patek’s laboratory at Duke University, Jorge’s hope was to design a novel pendulum-based measurement device that required a reduced or frictionless point of rotation. Thinking “outside the box”, he landed upon a new technology – air bearings – as a possible solution. Following a series of design and application discussions with the engineers at OAV, he knew he was on the right track. Subsequent tests have proven him correct.
By replacing the traditional roller bearing at the fulcrum of the dual rigid pendulum test assembly with the OAV Air Roller Bearing, Jorge was able to overcome the hurdle presented by traditional bearings in collecting quality test data. His conclusions were clear: “friction has a large effect on energy measurement at these scales (micro-joules) …and…the amount of energy measured using the OAV Air Bearings is at least six times greater than when we used traditional ball bearings.”
The clear corollary to this conclusion is the obvious loss of energy lost to the traditional bearings rotational motion and the long-term advantages of utilizing air bearings over traditional ones. Jorge also concluded that while the air bearing is clearly more costly than traditional bearings, one can “justify (it’s use) with savings in time by eliminating maintenance between tests and the precision and accuracy that is impossible with traditional bearings.” OAV’s engineers concur. The use of air bearings may be more costly initially but they reduce long term costs through less maintenance and down time (and associated labor) costs, increased long term reliability, and accuracy.
OAV engineers have similar stories in much of their supportive work for University and corporate based researchers. Whether one is testing the energy generated by the trap jaw ant mandible strike or the energy generated by the wings of a common house fly, OAV is working to supply solutions for the future.
THE RESULTS
Replacing the traditional roller ball bearing with the OAV Roller Air Bearing produced the following results:
Measured energy at least six times greater than with traditional ball bearings.
Eliminated frictional losses and improved measurement fidelity.
Enabled capture of microjoule-level energy events with high precision.
Reduced maintenance, downtime, and labor costs.
These results allowed Jorge and Dr. Patek's team to achieve their research goals and open new possiblities for understanding the biomechanics of trap-jaw ants. OAV continues to support universities and research institutions with precision air bearing solutions for the most demanding measurement and motion control applications.
REFERENCES
1. Jorge, J. F., Bergbreiter, S., & Patek, S. N. (2021). Pendulum-based measurements reveal impact dynamics at the scale of a trap-jaw ant. Journal of Experimental Biology, 224, jeb232157. DOI: 10.1242/jeb.232157.