Date of Award

Spring 1-1-2016

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Mechanical Engineering

First Advisor

Mark E. Rentschler

Second Advisor

Rong Long

Third Advisor

Virginia L. Ferguson

Fourth Advisor

Franck Vernerey

Fifth Advisor

Kurt Maute

Abstract

This report details the experimental and computational work done to characterize the adhesion response between a soft synthetic substrate and a smooth and micro-patterned PDMS surface. The main motivation for this work comes from the design and development of a robotic capsule endoscope (RCE), an actively controlled surgical device capable of navigating through the gastrointestinal (GI) tract for diagnostic and therapeutic purposes. Adhesion is a critical mobility parameter and must be well characterized and understood in order to optimize the mobility of the RCE through the GI tract.

A detailed background and motivation for this work is provided in Chapter 1. Adhesion and its various mechanisms are discussed as well as previous work done by the Advanced Medical Technologies Laboratory (AMTL) and other groups in the research area of RCEs.

Chapter 2 presents the first aim of this work: characterizing the adhesion response of an RCE tread with respect to various RCE design parameters. An adhesion tack test using a flat cylindrical probe was done in order to characterize the adhesion response between a smooth PDMS surface and a soft synthetic substrate material. Critical adhesion response variables were identified and characteristic equations for each variable were defined.

Chapter 3 presents the second aim of this work: characterizing the work of adhesion between a micro-patterned surface and a soft synthetic tissue. Due to some of the limitations of the experimental methods developed in Aim 1, a new experimental method was designed and executed in order to characterize the adhesion energy at the contact between a soft synthetic tissue and a smooth and micro-patterned PDMS substrate. Classical contact mechanics and adhesion theory was used to analyze experimental data and extract the adhesion energy.

Chapter 4 presents the third aim of this work: characterizing the adhesion energy with respect to micro-pattern geometrical features using finite element modeling. It is critical to understand how the adhesion energy parameter is affected when the micro-pattern geometry is varied. This will ultimately help inform a structural model using multi-phase physics and a design optimization algorithm to model the mobility of an RCE through the lumen of intestinal bowel tissue.

The final chapters (Chapters 5 and 6) present the overall conclusions and discussions from this work.

Available for download on Sunday, September 27, 2020

Share

COinS