Civil Engineering Graduate Seminar:
Thursday, October 24, Room 641 Dow Building, 4:00-5:00 pm
Title: A Study of Vibrations and a Method to Suppress Them
Presenter: Benjamin Winter
Vibrations developed during drilling present challenges in an array of industries including mechanical, medical, structural, and oil extraction. Velocity weakening, intracranial vibrations, large amplitude standing pressure waves in material cavities, and failure of drill strings are prominent issues among these fields. Stick-slip (torsional) and bit-bounce (axial) vibrations have been found to be particularly problematic in precision drilling jobs such as machining to tight tolerances, dismantling vibration-sensitive devices, and surgical work. Current technologies to detect and suppress systematic vibrations have several shortcomings including malfunctioning, complete failure, complexity, and high power consumption. This paper proposes a method to suppress vibrations of drilling material surfaces using adaptive positive position feedback (APPF) control for efficient tunable damping. An experiment-based parametric study has been conducted to determine the relationship of force, rotational velocity, and acceleration on both drill vibrations and drilling material surface vibrations. Results of a parametric study and Rational Polynomial Fraction method are used to estimate fundamental behaviors of the drilling system to create a refined numerical model for simulating the drilling process. An APPF controller together with the model provided a method to evaluate new actuator designs for vibration suppression and has shown a 69.8% reduction of displacement vibrations.
Benjamin Winter is starting his second year of his PhD program in Civil Engineering at Michigan Tech. He is a student member of ASCE and AISC. During the school year, he works as a Research Assistant for his advisor Dr. R Andrew Swartz. During the school year he also mentors undergraduate students beginning research in structural control and system identification while preparing for K’nex bridge competitions. This fall he is continuing his interest in mentoring and teaching students as a Teaching Assistant for the undergraduate Structural Steel Design course and as a tutor for students for statics MEEM 2110.