Engineering Commons^™

Quality And Inspection Of Machining Operations: Review Of Condition Monitoring And Cmm Inspection Techniques 2000 To Present, John T. Roth, Laine Mears, Dragan Djurdjanovic, Xiaping Yang, Thomas Kurfess

Publications

In order to consistently produce quality parts, many aspects of the manufacturing process must be carefully monitored, controlled, and measured. The methods and techniques by which to accomplish these tasks has been the focus of numerous studies in recent years. With the rapid advances in computing technology, the complexity and overhead that can be feasibly incorporated in any developed technique has dramatically improved. Thus, techniques that would have been impractical for implementation just a few years ago can now be realistically applied.

This rapid growth has resulted in a wealth of new capabilities for improving part and process quality and …

Corrosion Effects On Tension Stiffening Behavior Of Reinforced Concrete, M. A. Shayanfar, M. Ghalehnovi, Amir Safiey

Publications

The investigation of corrosion effects on the tensile behavior of reinforced concrete (RC) members is very important in region prone to high corrosion conditions. In this article, an experimental study concerning corrosion effects on tensile behavior of RC members is presented. For this purpose, a comprehensive experimental program including 58 cylindrical reinforced concrete specimens under various levels of corrosion is conducted. Some of the specimens (44) are located in large tub containing water and salt (5% salt solution); an electrical supplier has been utilized for the accelerated corrosion program. Afterwards, the tensile behavior of the specimens was studied by means …

Space Suit Concepts And Vehicle Interfaces For The Constellation Program, D. M. Klaus, J. Metts, R. Kobrick, M. Mesloh, T. Monk, Et Al.

Publications

In carrying out NASA’s Vision for Space Exploration, a number of different environments will be encountered that will require the crew to wear a protective space suit. Specifically, four suited mission phases are identified as Launch, Entry & Abort profiles, Contingency 0g (orbital) Extravehicular Activity (EVA), Lunar Surface EVA and Martian Surface EVA. This study presents conceptual design solutions based on a previous architecture assessment that defined space suit operational requirements for four proposed space suit configuration options. In addition, a subset of vehicle interface requirements are defined for enabling umbilical and physical connections between the suits and the various …

Selection Of The Spraying Technologies For Over-Coating Of Metal-Stampings With Thermo-Plastics For Use In Direct-Adhesion Polymer Metal Hybrid Load-Bearing Components, M. Grujicic, V. Sellappan, Laine Mears, X. Xuan, Norbert Seyr, Marc Erdmann, Jochen Holzleitner

Publications

The suitability of various polymer-powder spraying technologies for coating of metal-stampings used in polymer metal hybrid (PMH) load-bearing automotive-component applications is considered. The suitability of the spraying technologies is assessed with respect to a need for metal-stamping surface preparation/treatment, their ability to deposit the polymeric material without significant material degradation, the ability to selectively overcoat the metal-stamping, the resulting magnitude of the polymer-to-metal adhesion strength, durability of the polymer/metal bond with respect to prolonged exposure to high-temperature/high-humidity and mechanical/thermal fatigue service conditions, and compatibility with the automotive body-in-white (BIW) manufacturing process chain. The analysis revealed that while each …

Internet Enabled Remote Driving Of A Combat Hybrid Electric Power System For Duty Cycle Measurement, Jarrett Goodell, Marc Compere, Wilford Smith, Mark Brudnak, Mike Pozolo, Et Al.

Publications

This paper describes a human-in-the-loop motion-based simulator interfaced to hybrid-electric power system hardware, both of which were used to measure the duty cycle of a combat vehicle in a virtual simulation environment. The project discussed is a greatly expanded follow-on to the experiment published in [1,7]. This paper is written in the context of [1,7] and therefore highlights the enhancements. The most prominent of these enhancements is the integration (in real-time) of the Power & Energy System Integration Lab (P&E SIL) with a motion base simulator by means of a “long haul” connection over the Internet (a geographical distance of …

Numerical Simulation Of Waves And Fronts In Inhomogeneous Solids, A. Berezovski, M. Berezovski, J. Engelbrecht, G. A. Maugin

Publications

Dynamic response of inhomogeneous materials exhibits new effects, which often do not exist in homogeneous media. It is quite natural that most of studies of wave and front propagation in inhomogeneous materials are associated with numerical simulations. To develop a numerical algorithm and to perform the numerical simulations of moving fronts we need to formulate a kinetic law of progress relating the driving force and the velocity of the discontinuity. The velocity of discontinuity is determined by means of the non-equilibrium jump relations at the front. The obtained numerical method generalizes the wave-propagation algorithm to the case of moving discontinuities …

A Lean Modeling Protocol For Evaluating Green Project Delivery, Leidy E. Klotz, Michael Horman, Mark Bodenschatz

Publications

The first vital step to leaning an operation is to model or map the processes used to deliver value in that operation. This allows the requisite understanding of where waste and non value-adding activity exists, and provides the foundation for improvement. Current protocols for modeling operations present the basic tenets for lean mapping, but tend to be based in manufacturing language, and are not easily adapted to capital facilities projects. “Green” or “sustainable” capital projects delivered using current project delivery systems seem to be laden with hidden waste. These projects tend to be more challenging to deliver due increased levels …

Derivation And Application Of A Conserved Orbital Energy For The Inverted Pendulum Bipedal Walking Model, Jerry E. Pratt, Sergey V. Drakunov

Publications

We present an analysis of a point mass, point foot, planar inverted pendulum model for bipedal walking. Using this model, we derive expressions for a conserved quantity, the “Orbital Energy”, given a smooth Center of Mass trajectory. Given a closed form Center of Mass Trajectory, the equation for the Orbital Energy is a closed form expression except for an integral term, which we show to be the first moment of area under the Center of Mass path. Hence, given a Center of Mass trajectory, it is straightforward and computationally simple to compute phase portraits for the system. In fact, for …

Real-Time System Identification For Impact-Based Part Positioning, Laine Mears, Jeannie Falcon

Publications

Simplified part positioning in manufacturing has been achieved using pushing or tapping actuation in place of more complex pick-and-place systems. However, positioning by impact introduces a new source of uncertainty: interfacial frictional effects of sliding, which can result in an uncontrollable and often poorlypredictable actuation distance. The described work provides a friction-based dynamic model of the sliding distance after impact that is used to predict static friction characteristics. A prototype system is simulated and validation data used to improve the model. A control algorithm is also described, tested and validated over a range of actuated masses.

Gps-Based Steering Needle Instrument, Carl Edward Wischmeyer

Publications

A a flight instrument enabling a pilot to intercept and precisely follow a predefined GPS track. The instrument­ known as a GPS steering indicator-provides a visual display which is similar in appearance to other aircraft instruments (and therefore instantly recognizable to nearly all pilots). However, the instrument is preferably differen­tiated somewhat in its visual appearance to convey to the pilot the fact that it displays steering commands rather than cross track error. An indicator needle deflects to instruct the pilot which way to turn and how much to turn in order to intercept and fly along a predefined GPS track. …

Soldier/Hardware-In-The-Loop Simulation-Based Combat Vehicle Duty Cycle Measurement: Duty Cycle Experiment 2, Mark Brudnak, Mike Pozolo, Victor Paul, Syed Mohammad, Marc Compere, Et Al.

Publications

This paper describes a human-in-the-loop motion-based simulator interfaced to hybrid-electric power system hardware both of which were used to measure the duty cycle of a combat vehicle in a virtual simulation environment. The project discussed is a greatly expanded follow-on to the experiment published in [1]. This paper is written in the context of [1] and therefore highlights the enhancements. The most prominent of these enhancements is the integration (in real-time) of the Power & Electric System Integration Lab (P&E SIL) with a motion base simulator by means of a “long haul” connection over the Internet (a geographical distance of …

Impulsive-Actuation Part Positioning Through Constrained Energy Balance Planning, Laine Mears, Thomas R. Kurfess

Publications

Impulsive actuation has been researched in the past two decades as an inexpensive alternative to multi-degree-of-freedom precision positioning systems. The position of a sliding workpiece can be controlled by a 2-degree-offreedom actuation system through simple pushing path planning. However, the final part position as a result of the last touch of the actuator is subject to uncertainty in the friction model used for actuation planning, particularly the free-sliding distance undergone by the workpiece after losing contact with the actuator. This paper first reviews an impact planning method, then augments it using a restitutionbased model that results in an explicit actuator …

Data Mining Methods Applied To Flight Operations Quality Assurance Data: A Comparison To Standard Statistical Methods, Alan J. Stolzer, Carl Halford

Publications

"In a previous study, multiple regression techniques were applied to Flight Operations Quality Assurance-derived data to develop parsimonious model(s) for fuel consumption on the Boeing 757 airplane. The present study examined several data mining algorithms, including neural networks, on the fuel consumption problem and compared them to the multiple regression results obtained earlier. Using regression methods, parsimonious models were obtained that explained approximately 85% of the variation in fuel flow. In general data mining methods were more effective in predicting fuel consumption. Classification and Regression Tree methods reported correlation coefficients of .91 to .92, and General Linear Models and Multilayer …

Heating Methods And Detection Limits For Infrared Thermography Inspection Of Fiber-Reinforced Polymer Composites, Jeff R. Brown, H. R. Hamilton

Publications

The use of fiber-reinforced polymer (FRP) composites to strengthen existing civil infrastructure is expanding rapidly. Many FRP systems used to strengthen reinforced concrete are applied using a wet lay-up method in which dry fibers are saturated on site and then applied to the surface. This research investigated using infrared thermography (IRT) as a nondestructive evaluation (NDE) tool for detecting air voids and epoxy-filled holes in FRP systems bonded to a concrete substrate. Four small-scale specimens with FRP thicknesses ranging from 1 to 4 mm (0.04 to 0.16 in.) containing fabricated defects were constructed and inspected in a laboratory setting. Three …

Curricular Value And Instructional Needs For Infusing Engineering Design Into K-12 Technology Education, David K. Gattie, Robert C. Wicklein

Publications

An overarching objective of Technology Education in the U.S. is to improve technological literacy among K-12 students (DeVore, 1964; Savage and Sterry, 1990; International Technology Education Association, 1996, 2000, 2003). This is addressed in part through a focus on end-product technology and the use and importance of various technologies in society (Savage and Sterry, 1990). While such a focus is certainly necessary, it may not be sufficient if the objective is to infuse engineering into the technology education field. Current efforts at the University of Georgia propose adjusting the focus of Technology Education to a defined emphasis on engineering design …

Resources: Student Friendly Modeling Materials, Todd R. Kelley, Jared Berrett

Publications

The article presents cost-effective materials for elementary classrooms that allow students to create models. These materials include card stock, clay, cable or zips ties, fasteners and bolts, and commercially manufactured building kits such as LEGOs, Erector Sets, Tinkertoys and K'Nex. In addition, the author asserts the importance of using such materials in promoting student learning of technology and engineering.

Critical Features Of Engineering Design In Technology Education, Paul A. Asunda, Roger Hill

Publications

The purpose of this study was to find critical features of engineering design that can be incorporated within technology education learning activities, and develop a rubric for assessing these features. Data were collected through semi-structured interviews with three professors actively involved in engineering education. Supporting documents such as engineering design course outlines and rubrics were also examined. Using a phenomenological approach, this study identified the concept of engineering design, key features of the engineering design process, and critical elements that should be assessed in an engineering design activity in the context of technology education. A key product of the study …

Should There Be A National Curriculum For Technological Literacy?, Laura J. Hummell, Ethan B. Lipton, Melissa Morrow, Jerry Streichler, Karen Zuga

Publications

The author discusses her belief that the United States should have a national curriculum for technological literacy. The author asserts that there are huge discrepancies and deficiencies existing in technology-based curricula, and as a result students in the United States are being ill-prepared for living and working in a globally based economy and society. The author believes that if a national curriculum for technological literacy is developed it should resemble the Standards for Technological Literacy (2000/2002), which was created by the International Technology Education Association. The author points out that in order for such a curriculum to be successful it …

Resources: Building Big (And Small), Todd R. Kelley

Publications

The article offers a set of videos and web resources for elementary teachers to help them explore five different structures, including bridges, domes, skyscrapers, dams, and tunnels, that have been built big to meet the human needs and wants. It includes the miniseries video "Building Big" by David Macaulay and the website www.pbs.org/buildingbig.com.