Curriculum Vitae

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Current Research

Biomechanics and Biomaterials in Orthopaedics Website

Multi-Parameter Nano- and Micro-Mechanical Characterization of Biomaterials

The objective of this work is to experimentally determine and model the mechanical behavior of biomaterials such as bone, connective tissue, and bio-polymers, using nano- and micro-indentation techniques. Multi-parameter modeling of mechanical properties and estimation of the stresses and strains that occur are considered the key elements of this research.

Tribological Investigation of the Carbon-Carbon Composite Brake System

Dissipation of heat in aircraft braking systems is heavily influenced by the tribological conditions at the contacting surfaces and the near-surface layers. The brake tribo-system is fully transient in nature; therefore, a great opportunity exists for research aimed predicting carbon-carbon composite friction and wear properties over the large temperature range encountered during routine operation. This research focuses on: (1) The investigation of carbon-carbon composite friction as a function of temperature, environment, and fiber orientation. (2) Examination and characterization of the worn specimen contact region. (3) Investigation of the effects of non-carbon additives on friction and wear behavior.

Tribological Investigation of the Chip-Tool Interface by Controlled-Environment Metal Cutting

Machining processes, such as turning, milling, and boring, are widely used methods for finishing a large variety of metallic system components, and all utilize various types of cutting tools. The tribological interface between the cutting tool surface and the machined chip, as it slides across the surfaces of the tool, is a challenging system to study. The nature of the contact conditions at this chip/tool interface includes limited external access or probing capabilities, potentially high temperature generation, and complex tribo-chemical contact conditions. The objective of this research is to investigate the tribological and physical phenomena that occur at the chip/tool interface during metal cutting operations. This has been accomplished through the development of an existing 1.5 kW turning station, constructed in a vacuum chamber. This system is capable of operation in pressures as low as 10-7 torr, and can be used to investigate a wide variety of gaseous environments. Cutting speed, feed rate, and depth-of-cut may be controlled, and the three orthogonal cutting forces may be monitored simultaneously. This allows one to study the relationship between chip morphology, tool wear, workpiece surface finish, and chip/tool friction. A second objective is to determine if friction at the chip/tool interface may be reduced using a tribo-chemically activated (i.e., via heat, atmosphere, and surface chemistry) boundary lubricant in the form of nano-structured wear resistant coatings containing boundary lubricant species, without externally applied liquid coolant/lubricant mixtures; and if so, to determine how friction is reduced, as monitored by the system's instrumentation.

Selected Recent Publications

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Direct comments, questions, and corrections to amedept@nd.edu