Michael D. Bryant - US grants

This project provides resources to procure equipment to support electromechanical devices research and contact physics research. The equipment comprises a vibration isolation table, power amplifiers and a signal processing computer. Two research projects will benefit from the availability of the equipment. The first is concerned with the development of a vibration control method for structures which support ultra precise systems (laser mounts, precise machining systems, navigational gyroscopes, etc). The vibration isolation table provides a quiescent environment for ultra precise experiments associated with this project. The method takes advantage of the magnetostrictive properties of materials made of iron and rare earth metals. The second project focuses on understanding the tribological phenomenon of thermoelastic instability, whereby sliding contact between a motor brush and rotor occurs over microscopic surface bumps (thermal mounds) on the brush face. The mound tends to move over the brush face in an unknown pattern. The research is directed at predicting this thermal mound motion. The equipment will also be used for general tribology research which emphasizes electrical contacts.

The wear of monolithic carbon electrical brushes will be studied. Analytical modeling of the particle ejection theory of brush wear will be compared with experimentally obtained results. The experimental apparatus will make it possible to observe the development and movement of hot spots in the contact area, generated due to both frictional heating and heating from the electrical current passing from the brush surface to the matching surface. The effect of a number of test parameneters will be determined and the results used to validate and improve the model.

An experimental study will be made to determine the effects of contact vibrations on friction and wear in dry sliding contact and to develop maps of optimal amplitude and frequency conditions to give minimal wear and/or friction for given conditions. Vibrations will be imposed from external actuators or generated by the sliding surfaces due to engineered surface roughness. The results will be used to develop and validate a model for the effect and to form the basis for design selection of operating conditions for components such as electrical brushes.

9713942 Bryant Initial studies have shown that micro-vibrations properly applied to bodies in sliding contact can reduce their wear by 50% or more. In this follow-up study the basic mechanisms involved will be studied and techniques will be developed to optimize the effect using passively generated vibrations for several target technologies, including automotive and aircraft brakes as well as electrical brushes. It is expected that near the end of the study subtle design changes can eventually be developed for automotive brake systems which will enable passive generation of vibrations that promote the vibration-induced wear reduction without having any deleterious side effects and that this could result in a very significant drop in brake wear. ***

This project has two central objectives: (1) Development of a thermodynamic characterization of degradation dynamics employing entropy (thermodynamic disorder) as the fundamental measure of degradation, and (2) Development of methods of measurement of state variables that are functionally related to entropy. The research tasks include: application of thermodynamic principles to characterize component degradation and lifetime, characterization of initial component lifetime, development of a mathematical framework for study of stochastic degradation dynamics, and development of methods for measurement of entropy related state variables. Through a theoretical and experimental investigation of degradation in machinery components, the project hopes to advance a scientific understanding of degradation dynamics, leading to improved engineering maintenance practice. This research could build a strong foundation for maintenance science that can potentially impact many manufacturing industries such as the semiconductor and aerospace industries.

9731221 Bryant This award provides funds to permit Dr. Michael D. Bryant, Mechanical Engineering Department, University of Texas at Austin, to pursue with Dr. Chung Kyun Kim, Department of Mechanical Engineering, Hongik University, Seoul, Korea, for 36 months, a program of cooperative research on improving friction brakes by eliminating tribological problems and reducing wear. The collaborators will seek to improve high speed brake systems through complementary efforts, with each researcher working to improve different aspects of disc brakes, later to be combined. The combined effort could result in efficient, long lasting brakes on high speed trains, airplanes, automobiles, and industrial machinery Dr. Kim will contribute a new disc design and will analyze nonlinear thermal behavior of the disc and brake pad system using the Finite Element Method. He will redesign materials and geometry on the disc to optimize removal of heat and minimize thermal expansion problems that lead to brake noise and premature brake wear. Dr. Bryant will contribute new brake pad and disc designs that incorporate patented techniques that reduce brake pad wear and extend (double) life. Cooperative research issues will focus on problems that arise when combining the two designs: (1) necessary redesigns of both systems, (2) solving any problems that would prevent the two systems from functioning in a combined manner, (3) extensive testing of the new brake system, and (4) technology transfer to industries in both countries. Doubling brake life and eliminating other tribological brake problems could save both societies billions of dollars. This project is relevant to the objectives of the U.S.-Korea Cooperative Science Program which seeks to increase the level of cooperation between U.S. and Korean scientists and engineers through the exchange of scientific information, ideas, skills, and techniques and through collaboration on problems of mut ual benefit. This project provides an international research experience for a U.S. graduate student. It also will add an international cooperative dimension to ongoing research under NSF Grant No. CMS-9713942, supported under the Surface Engineering and Tribology Program. Korean participation is supported by the Korea Science and Engineering Foundation (KOSEF). ***

This exploratory research grant provides the support for studies, with respect to fundamental facets as well as practical facets, of manufacturing processes of three-dimensional components in the micro-scale. Moreover, the study will include factors required to have components, so fabricated, to work together as three-dimensional micro-actuators. Letting a length-measure to represent the size of component, it is known that the volume of the component is proportional to the cube of the length-measure, and the surface of the component is proportional to the square of the length-measure. Given this fact, as one move from the much better understood macro world of manufacturing to the relatively unknown world of manufacturing in the micro world, surface dictated behavior as a part of the component would be much more important than the volume dictated behavior of the component. As such this research will place special emphasis on surfaces along with the material whose surfaces are be studied. As these components are expected to work together reliably when assembled to form actuators, materials as a factor also looms large in the studies. Other factor to be studied are method of measurement, handling, storage, among others, of micro-scale components.

If successful, the results of this exploratory research will improve the fundamental understanding of processes of manufacturing three-dimensional components in the micro-scale as well as factors which need to be taken into account when these components are assembled to form micro-actuators. A dominant factors in the fundamental understanding, which will be the bases for successful application, is reliability. The hope is that the aforementioned knowledge will lead to requisite methodologies for manufacturing in the micro-scale, especially in the truly three-dimensional world.

This grant provides funding for the development of micro-actuators, e.g., micro-motor, dynamic micro-gas bearing micro-continuously-variable speed-reducers. Inasmuch as magnetic fields, difficult to contain, have limited micro-scale use, two electrostatic motor drive concepts will be developed: (1) Variable Capacitance Motor - Variable capacitance motor minimizes energy of electric field in an air gap field that can change geometry. Rotor electrodes seek positions relative to stator electrodes of least potential energy stored in the electric field of an air gap between the rotor and stator. (2) Induced Charge Motor - Induced charge motor is based on a concept of induced polarization of charges of material in the motor creating a secondary electric field which aligns in a primary field. This variant of drive is the electric field analogy to an induction motor. To avoid stiction, contact between surfaces in relative motion must be avoided as in bearings. Among other concepts, micro-gas-bearings will be developed. Micro-grooves built into the shaft part of the motor will pump air or gas and build-up films that keep the shaft from touching the bearing and housing. In order to avoid stiction for start-stop, the bearing housing will be suitable coated with a thin film lubricant. For the above, and other actuators, advanced science-based modeling methods will be developed for underpinning design.

If successful, the results of this research will lead to new methods in the relatively new arena of manufacturing in the micro-scale of three-dimensional mechanical components needed for various actuators. In developing the methods, emphasis will be given to reliability in the use of components in actuators. Envisioned are applications of actuators in bio-medical, aerospace, as well as other consumer products for which micro-size is paramount. Of course the use of micro-size actuators has the additional advantage of being environmentally friendly.

0112199
Bryant
Support is provided for a multi-disciplinary workshop to identify important areas of research in tribology that involve biological, biomedical, and medical issues. This workshop willhave principal goals of providing an overview of the current state of the art and recommending new directions of research. The workshop will have approximately 40 to 50 participants, and feature several keynote speakers and participants from tribology, medicine, the biomedical implant community, and biology. The 2.5 day long
workshop's format will consist of the following:
Introductory session
Presentations by keynote speakers
Posters by attendees
Breakout sessions
Final half day wrap up session
The workshop results will be documented to provide valuable guidance for future research directions in tribology. Results of the workshop will be released into the public domain by the workshop organizing committee, as a report to NSF, and as an article to be submitted to one of the Tribology and Biomedical Engineering periodicals and as web-based documents. Special efforts will bemade to facilitate communication between the various scientific communities involved and to identify areas for future cross-disciplinary research. Special efforts will also be made to bring new researchers and graduate students to the meeting and to attract attendeed from underrepresented groups.
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This research aims at hybrid (discrete-continuous) computation for cyber-physical systems. The research augments the today-ubiquitous discrete (digital) model of computation with continuous (analog) computing, which is well-suited to the continuous natural variables involved in cyber-physical systems, and to the error-tolerant nature of computation in such systems. The result is a computing platform on a single silicon chip, with higher energy efficiency, higher speed, and better numerical convergence than is possible with purely discrete computation. The research has several thrusts: (1) Hardware: modern silicon chip technology is used to merge analog computing hardware on the same chip with digital hardware, the latter used for control and co-computation, (2) Architecture: methods are devised for making hybrid computing functionality accessible to the software, (3) Microarchitecture: Choices are made on the granularity, type and organization of analog and hybrid analog-digital functional units, and (4) Concrete application to a realistic cyber-physical system consisting of a team of robots.

The research extends modern computer architecture techniques, and advances in mixed analog/digital chip technology mainly developed in the context of communications, to hybrid computing for cyber-physical systems. It brings higher levels of energy efficiency to error-tolerant workloads that future computers will have to handle. The techniques developed can be extended to other systems in which efficient computation is a must, such as weather forecasting and high-energy physics. The work integrates research with education and includes plans for broad dissemination of the results obtained.

Planning Grant: I/UCRC for Intelligent Maintenance Systems (IMS)

1161021 University of Texas-Austin; Dragan Djurdjanovic

The University of Texas-Austin (UT-A) is seeking to join the existing I/UCRC for Intelligent Maintenance Systems (IMS) currently comprised of the University of Cincinnati (lead), the University of Michigan and the Missouri University of Science and Technology.

By joining the existing IMS Center, the UT-A will expand the ongoing IMS research with new ideas and foci grounded in the expertise and research interests of the UT faculty and students. Those new directions include predictive maintenance in semiconductor manufacturing, vehicle technologies, oil industry, renewable energy, power plants and biomedicine. The research in the proposed site will be realized through the following thrusts: 1) Information-theoretical approaches to condition-monitoring; 2) Data-driven methods for operating regime-dependent condition monitoring and prediction 3) Fault-tolerant control of complex engineering systems; 4) Predictive maintenance methods and paradigms in biomedicine and 5) System operations based on the information about the condition of system components.

The US economy spends more than $1 trillion for maintenance of critical assets, with more than 33% of these costs being wasted on ineffective maintenance. The UT-A intends to address this problem by contributing new ideas and leveraging inputs and experiences from numerous new industries that did not benefit enough from the predictive maintenance research. Expected advances in the ability to assess and predict the condition of an engineering system will increase the resilience and improve operation of machines in the future, with reduced waste of resources due to more effective maintenance intervention, and improved usage and productivity due to higher availability of equipment. Broader impacts of the research expected to take place at UT-A will be realized through regular meetings with industrial partners, short courses on diagnostics and maintenance open to industry and academe, regular participation and publication in relevant conferences, and partnerships with universities in the US and abroad.

The University of Texas at Austin site for the I/UCRC for Intelligent Maintenance Systems (IMS) intends to pursue and understand methods addressing the scientific and practical challenges of condition-based and predictive maintenance of complex engineering systems. The site plans to expand the on-going IMS research with new ideas and foci including predictive maintenance in semiconductor manufacturing, vehicle technologies, oil industry, renewable energy, power plants and biomedicine. The University of Texas at Austin site intends to complement existing IMS efforts through focus on new approaches to diagnostics and prognostics in complex engineering systems, utilization of advanced diagnostics and predictive maintenance methods for monitoring of systems in a human body, and maintenance decision-making in distributed systems, with limited availability of distributed resources and uncertain supply and demand characteristics.

It is estimated that the US economy spends more than $1 trillion for maintenance of critical assets, with more than 33% of these costs being wasted on ineffective maintenance. Optimization of these maintenance systems has the potential to greatly improve overall industrial productivity. The University of Texas at Austin Site of IMS intends to extend the research outcomes it brings to the center to new industries that have formerly not benefited from predictive maintenance research. The site plans to broadly disseminate research results through regular meetings with industrial partners, short courses on diagnostics and maintenance open to industry and academe, regular participation and publication in relevant conferences, and partnerships with universities in the US and abroad. They intend to actively promote diversity among students and researchers by leveraging the tremendous infrastructure UT offers in this regard.