Federico De Paoli | University of South Florida (original) (raw)
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I would like to thank my advisor Dr. Volinsky. Without his guidance, this thesis could not be pub... more I would like to thank my advisor Dr. Volinsky. Without his guidance, this thesis could not be published. I would also like to thank my thesis committee members, Professor Rasim Guldiken and Professor Nathan Gallant for their direction, dedication, and invaluable advice along this project. I also want to thank the doctorate candidate Asma Sharfeddin for providing valuable help in the laboratory for the production of the samples used in this research work and thesis. i TABLE OF CONTENTS LIST OF TABLES .
Volume 7B: Fluids Engineering Systems and Technologies, 2015
DESCRIPTION Since the creation of advanced knives and firearms with high rates of speed, safety h... more DESCRIPTION Since the creation of advanced knives and firearms with high rates of speed, safety has always been a vital issue for armed forces. A disadvantage of a regular fabric Kevlar is that, although it has an effective resistance against the impact of bullets, it reveals its weakness in the case of a stab wound. Under these circumstances, a new executable technology of fibers that improves the ballistic performance of the materials utilized in body armors is an essential necessity to build high quality and protective vests which are not only bulletproof, but also stabbed-resistant. The purpose of this study is to investigate the physics and concepts of shear thickening fluids and perform an analytical CFD simulation of liquid body armors which are consisted of a combination of polyethylene glycol liquid and nanoparticles of silica.
MethodsX, 2015
Procedure to establish full contact between the sample and the 1 mm diameter cylindrical flat pun... more Procedure to establish full contact between the sample and the 1 mm diameter cylindrical flat punch tip to measure polydimethylsiloxane (PDMS) mechanical properties using the Hysitron TriboIndenter is described. This procedure differs from the standard automated indentation because each indent has to be performed manually after establishing full contact with the sample surface. Incomplete contact happens because of the sample tilt with respect to the flat punch surface and results in incorrect elastic modulus values. Automated indentation results in incorrect values of the elastic modulus due to initial incomplete contact between the flat punch and the PDMS sample surface, caused by the tilt, and using the unloading slope, which is affected by viscoelastic soft polymer deformation. Correct procedure requires establishing the full contact between the tip and the sample. This is achieved by moving the tip into the sample in 1-2 mm increments, up to 40-80 mm maximum combined displacement, until the loading stiffness no longer increases. The elastic modulus is calculated from the loading stiffness and the diameter of the flat punch, instead of the unloading stiffness, which is larger due to viscoelastic unloading. After establishing the full contact, other mechanical testing can be conducted.
I would like to thank my advisor Dr. Volinsky. Without his guidance, this thesis could not be pub... more I would like to thank my advisor Dr. Volinsky. Without his guidance, this thesis could not be published. I would also like to thank my thesis committee members, Professor Rasim Guldiken and Professor Nathan Gallant for their direction, dedication, and invaluable advice along this project. I also want to thank the doctorate candidate Asma Sharfeddin for providing valuable help in the laboratory for the production of the samples used in this research work and thesis. i TABLE OF CONTENTS LIST OF TABLES .
Volume 7B: Fluids Engineering Systems and Technologies, 2015
DESCRIPTION Since the creation of advanced knives and firearms with high rates of speed, safety h... more DESCRIPTION Since the creation of advanced knives and firearms with high rates of speed, safety has always been a vital issue for armed forces. A disadvantage of a regular fabric Kevlar is that, although it has an effective resistance against the impact of bullets, it reveals its weakness in the case of a stab wound. Under these circumstances, a new executable technology of fibers that improves the ballistic performance of the materials utilized in body armors is an essential necessity to build high quality and protective vests which are not only bulletproof, but also stabbed-resistant. The purpose of this study is to investigate the physics and concepts of shear thickening fluids and perform an analytical CFD simulation of liquid body armors which are consisted of a combination of polyethylene glycol liquid and nanoparticles of silica.
MethodsX, 2015
Procedure to establish full contact between the sample and the 1 mm diameter cylindrical flat pun... more Procedure to establish full contact between the sample and the 1 mm diameter cylindrical flat punch tip to measure polydimethylsiloxane (PDMS) mechanical properties using the Hysitron TriboIndenter is described. This procedure differs from the standard automated indentation because each indent has to be performed manually after establishing full contact with the sample surface. Incomplete contact happens because of the sample tilt with respect to the flat punch surface and results in incorrect elastic modulus values. Automated indentation results in incorrect values of the elastic modulus due to initial incomplete contact between the flat punch and the PDMS sample surface, caused by the tilt, and using the unloading slope, which is affected by viscoelastic soft polymer deformation. Correct procedure requires establishing the full contact between the tip and the sample. This is achieved by moving the tip into the sample in 1-2 mm increments, up to 40-80 mm maximum combined displacement, until the loading stiffness no longer increases. The elastic modulus is calculated from the loading stiffness and the diameter of the flat punch, instead of the unloading stiffness, which is larger due to viscoelastic unloading. After establishing the full contact, other mechanical testing can be conducted.