Mechanical Engineering Commons^™

Lester Larsen: Progress Of Tractor Test Work 1946 -1956, Tractor Museum

Individuals Associated with the Nebraska Tractor Test

When Lester F. Larsen was hired as Engineer in Charge of the Nebraska Tractor Test, the laboratory had been inactive since 1941 due to World War II. Much of the test equipment was out of order and in need of repair. He kept a journal called the Progress of Tractor Test Work. This journal of day to day activities extended from 1946 through 1956.

Developing A Convective Code With Vorticity Transport In Upwind Method, Je -Ee Ho

Journal of Marine Science and Technology–Taiwan

The Navier-Strokes equations are usually used to solve the convective problems, however, to satisfy the conversation of mass, the uncertainty of pressure terms will easily trigger off the numerical divergence during the iterative process; which results in a calculating failure and makes the numerical solutions impossible. In this study, a vorticity–transport method that avoids the involvement of pressure terms by cross differentiate the governing equations and meets the flow conservation with stream function was proposed. With the aid of the upwind scheme and implicit method, an effective transformation from the partial differential equations into the vortex potential algebraic equations would …

Characteristic Study Of Mhd Minipump, Je -Ee Ho

Journal of Marine Science and Technology–Taiwan

The present study aims to develop and discuss the availability of the Magneto Hydrodynamics Minipump (MHD) as a miniaturizative part specified for precise manufacturing or medical application. Based on the MHD theory, an available working current (1.8A) induced by lower voltage (0-12V) and weaker magnetic intensity (0.04T) meets the need in mini-system operation. However, precise estimations of working capacity, maximum head, dynamic head, and static head in various electrolyte concentrations are necessary. Furthermore, this work also provides a simplified analytic model with a static balance between Lorentz force, surface tension force, and body force. Compared with analytic solutions and experimental …

2008 Fall Engr333 Project Assignment, Matthew K. Heun

ENGR 333

The Fall 2008 semester ENGR333 project assessed the feasibility of a Green Revolving Fund for Calvin College. I asked the students “What would it take to implement a Calvin Energy Efficiency Fund (CEEF)?”

The project emerged from the work of the previous year’s students who uncovered the concept of green revolving funds.

Immediately after the Fall 2008 semester, I went on sabbatical to South Africa for all of 2009. While I was away, the Calvin administration established the Calvin Energy Recovery Fund (CERF). Over the next decade, CERF saved hundreds of thousands of dollars in energy costs and was …

Reliability Analysis Of Plank Decks, Andrzej S. Nowak, Christopher D. Eamon

Civil and Environmental Engineering Faculty Research Publications

The objective of this study is to summarize the load and resistance criteria for highway bridge plank decks, and to estimate the reliability of plank decks designed by AASHTO Code. Both transverse and longitudinal planks for a variety of typical stringer spacings and plank sizes are considered. Truck traffic load data is based on the model used to calibrate the 1994 AASHTO LRFD Code. However, for plank decks, wheel load rather than whole vehicle weight is most important, and these statistics are developed for this study. For wood planks, dead load and dynamic load are not significant. The limit state …

International Energy Agency Bestest For Ground Coupled Heat Transfer, Joel Neymark, Ron Judkoff, Michael Crowley

Reports

The objective of this project is to assess the accuracy of building energy analysis tools that have incorporated detailed models for predicting ground-coupled heat transfer related to floor slab and basement constructions. An executive summary is to be found in the main report.

Evaluating Three-Dimensional Effects On The Behavior Of Compliant Bistable Micromechanisms, Brian B. Cherry, Larry L. Howell, Brian D. Jensen

Faculty Publications

Fully compliant bistable micromechanisms (FCBMs) have potential use in numerous applications, including switches, relays, shutters, and low-power sensing arrays. Two-dimensional finite element models for these FCBMs have been used in device analysis and design, and provided an adequate match to preliminary experimental data. However, with more extensive experimentation over a large range of designs, some results proved to be radically different than predicted, with trends not consistent with effects such as stiction or electrostatic forces. Two different types of behavior, Behavior 1 and Behavior 2, are observed and explained, only one of which is predicted by 2-D models. This paper …

On Cracks And Delaminations Of Thermal Barrier Coatings Due To Indentation Testing: Experimental Investigations, Jin Yan, Thorsten Leist, Marion Bartsch, Anette M. Karlsson

Mechanical Engineering Faculty Publications

Rockwell indentation testing as a method of establishing the interfacial fracture toughness of thermal barrier coatings is investigated. To this end, indentation tests have been systematically performed on coatings with yttria-stabilized zirconia top coat deposited by electron beam physical vapor deposition. Specimens in “as-coated” condition and after heat treatment in air have been studied. Unexpectedly, indentation of the heat-treated samples resulted in smaller delaminations than the as-coated samples, suggesting an increase in fracture toughness for coatings subjected to elevated temperatures. Careful image analyses of the cross-section of the indented area show that the ceramic top coat undergoes a complex damage …

Inter-Frequency Bias Estimation For The Gps Monitor Station Network, Donny Holaschutz, Robert H. Bishop, R. Benjamin Harris, Brian Tolman

Mechanical Engineering Faculty Research and Publications

The inter-frequency bias (IFB) is present in all dual frequency combinations of GPS pseudorange and carrier phase observables. It is caused by the path dependent signal delays in both the satellite and receiver. That delay can be directly measured for a space vehicle prior to launch, or for a ground based receiver prior to its being used in the field. However the bias is known to drift, and monitoring the delay estimate by direct measurement is time consuming for ground based receivers and impossible for deployed space vehicles. Hansen (2002) examined the observability of IFB through a global model of …

Finite Element Analysis Using Nonconforming Mesh, Ashok V. Kumar, Ravi Buria, Sanjeev Padmanabhan, Linxia Gu

Department of Mechanical and Materials Engineering: Faculty Publications

A method for finite element analysis using a regular or structured grid is described that eliminates the need for generating conforming mesh for the geometry. The geometry of the domain is represented using implicit equations, which can be generated from traditional solid models. Solution structures are constructed using implicit equations such that the essential boundary conditions are satisfied exactly. This approach is used to solve boundary value problems arising in thermal and structural analysis. Convergence analysis is performed for several numerical examples and the results are compared with analytical and finite element analysis solutions to show that the method gives …

Deep Sea Underwater Robotic Exploration In The Ice-Covered Arctic Ocean With Auvs, Clayton Kunz, Chris Murphy, Richard Camilli, Hanumant Singh, John Bailey, Ryan M. Eustice, Chris Roman, Michael Jakuba, Claire Willis, Taichi Sato, Ko-Ichi Nakamura, Robert A. Sohn

Graduate School of Oceanography Faculty Publications

The Arctic seafloor remains one of the last unexplored areas on Earth. Exploration of this unique environment using standard remotely operated oceanographic tools has been obstructed by the dense Arctic ice cover. In the summer of 2007 the Arctic Gakkel Vents Expedition (AGAVE) was conducted with the express intention of understanding aspects of the marine biology, chemistry and geology associated with hydrothermal venting on the section of the mid-ocean ridge known as the Gakkel Ridge. Unlike previous research expeditions to the Arctic the focus was on high resolution imaging and sampling of the deep seafloor. To accomplish our goals we …

Multi-Functional, Self-Sensing And Automated Real-Time Non-Contact Liquid Dispensing System, Qiong Shen

Dissertations

Liquid dispensing in the order of pico-liter has become more and more important in biology, electronics and micro-electronic-mechanical-system (MEMS) during the past two decades due to the rapid progress of researches on the deoxyribonucleic acid (DNA) microarray, compact and low-cost direct write technology (DWT), organic semiconductors and nano-particles.

The existing approaches, commercialized or experimental, to liquid dispensing in minute amounts have one common shortcoming: open loop control, i.e., they have no direct control on the quality of dispensed liquid. In contrast, the SmartPin has intrinsic self-sensing capability to not only control the process of liquid dispensing, but also the results …

Dem Simulated Radial And Axial Pressure In A Cylindrical Granular Column, Meng Cui

Theses

The study of packed beds of granular spheres and their applications are of great interest to industries, and one of the most important subjects that has been studied is cylindrical beds. In 1895, H. A. Janssen discovered that in a vertical cylinder the pressure measured at the bottom does not depend upon the height of the filling in contrast to Newtonian fluids that possess linear hydrostatic pressure equilibrium. One of assumptions of his theory stated that the horizontal pressure is proportional to the vertical. In this thesis, this physical hypothesis is investigated using Discrete Element Simulations of inelastic with a …

The Development Research On Zhoushan Shipbuilding And Ship Repair Industry, Jing Zhou

World Maritime University Dissertations

No abstract provided.

Tooth Engagement Evaluation Of Involute Spline Couplings, Robert R. Robins

Theses and Dissertations

Spline couplings are used in applications involving high torque; however, due to variations in teeth clearances, all teeth in spline couplings do not engage simultaneously, causing some of the teeth to carry a disproportionately large portion of the total load. Variations in tooth-to-tooth clearances mean the first pair of teeth to engage will carry more load and fail sooner. This has lead to an industry practice of designing splines around the criteria that only 25-50% of the teeth on a spline coupling will engage and carry the load, and the load is generally assumed to be uniformly distributed. This research …

High-Impact, Energy-Absorbing Vehicle Barrier System : United States Patent 7,410,320 B2, Ronald K. Faller, Dean L. Sicking, John R. Rohde, John D. Reid, Robert W. Bielenberg, James C. Holloway, Karla A. Polivka

Department of Mechanical and Materials Engineering: Faculty Publications

A high-impact, energy-absorbing vehicle barrier system generally includes a substantially rigid outer containment wall coupled via strap assemblies with an energy-absorbing inner impact wall, and energy-absorbing cartridges strategically positioned between the impact wall and containment wall. The impact wall is constructed of a number of tubes coupled with one another to present a substantially smooth, unifonn surface to passing vehicles. The energy-absorbing cartridges generally consist of a foam member or a number of foam sheets which compress and crush between the containment wall and impact wall to absorb energy from an errant vehicle striking the face of the impact wall, …

High-Level, Product Type-Specific Programmatic Operations For Streamlining Associative Computer-Aided Design, Nathan W. Scott

Theses and Dissertations

Research in the field of Computer Aided Design (CAD) has long focused on reducing the time and effort required of engineers to define three dimensional digital product models. Parametric, feature-based modeling with inter-part associativity allows complex assembly designs to be defined and re-defined while maintaining the vital part-to-part interface relationships. The top-down modeling method which uses assembly level control structures to drive child level geometry has proved valuable in maintaining these interfaces. Creating robust parametric models like these, however, is very time consuming especially since there can be hundreds of features and thousands of mathematical expressions to create. Even if …

Optimization Constrained Cad Framework With Iso-Performing Design Generator, Kelly Eric Bowman

Theses and Dissertations

Design decisions have a large impact early in the design process. Optimization methods can help engineers improve their early decision making, however, design problems are often ill-posed for optimization at this early stage. This thesis develops engineering methods to use optimization during embodiment design, despite these difficulties. One common difficulty in designing mechanical systems is in handling the effects that design changes in one subsystem have on another. This is made more difficult in early engineering design, when design information is preliminary. Increased efforts have been made to use numerical optimization methods in early engineering design – because of the …

Product Focused Freeform Fabrication Education, Frank W. Liou, Ming-Chuan Leu

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Presented in this paper is our experience of teaching freeform fabrication to students at the Missouri University of Science and Technology, and to high school students and teachers. The emphasis of the curriculum is exposing students to rapid product development technologies with the goal of creating awareness to emerging career opportunities in CAD/CAM. Starting from solid modeling, principles of freeform fabrication, to applications of rapid prototyping and manufacturing in industry sponsored product development projects, students can learn in-depth freeform fabrication technologies. Interactive course content with hands-on experience for product development is the key towards the success of the program.

Microstructural Characterization Of Diode Laser Deposited Ti-6al-4v, Tian Fu, Zhiqiang Fan, Syamala R. Pulugurtha, Todd E. Sparks, Jianzhong Ruan, Frank W. Liou, Joseph William Newkirk

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Laser Direct Metal Deposition (DMD) is an effective approach to manufacturing or repairing a range of metal components. The process is a layer-by-layer approach to building up a three dimensional solid object. The microstructure influences mechanical properties of the deposited parts. Thus, it is important to understand the microstructural features of diode laser deposited parts. This paper presents a microstructure analysis of a diode laser deposited Ti-6Al-4V onto a Ti-6Al-4V substrate. laser deposited parts. This paper presents a microstructure analysis of a diode laser deposited Ti-6Al-4V onto a Ti-6Al-4V substrate.

Freeform Fabrication Of Zirconium Diboride Parts Using Selective Laser Sintering, Ming-Chuan Leu, Erik B. Adamek, Tieshu Huang, Greg Hilmas, Fatih Dogan

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Using the Selective Laser Sintering (SLS) process, both flexural test bars and 3D fuel injector components have been fabricated with zirconium diboride (ZrB₂) powder. Stearic acid was selected as the binder. Values of SLS process parameters were chosen such that the green parts could be built with sharp geometrical features and that the sintered parts could have good mechanical properties. After binder burnout and sintering, the SLS fabricated ZrB₂ test bars achieved 80% theoretical density, and the average flexural strength of the sintered samples was 195 MPa. These values demonstrate the feasibility of the SLS process for …

Direct 3d Layer Metal Deposition, Jianzhong Ruan, Lie Tang, Todd E. Sparks, Robert G. Landers, Frank W. Liou

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Multi-axis slicing for solid freeform fabrication (SFF) manufacturing processes can yield non-uniform thickness layers, or 3D layers. Using the traditional parallel layer construction approach to build such a layer leads to a staircase which requires machining or other post processing to form the desired shape. This paper presents a direct 3D layer deposition approach. This approach uses an empirical model to predict the layer thickness based on experimental data. The toolpath between layers is not parallel; instead, it follows the final shape of the designed geometry and the distance between the toolpath in the adjacent layers varies at different locations. …

Layer-To-Layer Height Control For Laser Metal Deposition Processes, Lie Tang, Jianzhong Ruan, Todd E. Sparks, Robert G. Landers, Frank W. Liou

Mechanical and Aerospace Engineering Faculty Research & Creative Works

A Laser Metal Deposition (LMD) height controller design methodology is presented in this paper. The height controller utilizes the Particle Swarm Optimization (PSO) algorithm to estimate model parameters between layers using measured temperature and track height profiles. The process model parameters for the next layer are then predicted using Exponentially Weighted Moving Average (EWMA). Using the predicted model, the powder flow rate reference profile, which will produce the desired layer height reference, is then generated using Iterative Learning Control (ILC). The model parameter estimation capability is tested using a four-layer deposition. The results demonstrate the simulation based upon estimated process …

Direct-To-Part Machining Waste Recycling Using Laser Metal Deposition, Todd E. Sparks, Frank W. Liou

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Laser metal deposition typically uses metal powders as the build material of choice. The ability to reprocess waste materials using this technology would significantly reduce the material cost and cradle-to-grave energy content of parts produced using these methods. This capability will also greatly increase the utility of laser deposition, to potential industrial uses. This paper explores the usage of machining chips as an alternate source of build material. Topics covered include material handling, material preprocessing, and comparison to powder- based deposition.

Modeling And Experimental Results Of Concentration With Support Material In Rapid Freeze Prototyping, Frances D. Bryant, Ming-Chuan Leu

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Ice structures with complex geometries and overhung areas are created by the Rapid Freeze Prototyping (RFP) process in a sufficiently cool environment by freezing water into ice as the main material in conjunction with a eutectic dextrose-water solution as the sacrificial support material. The supported areas in an ice structure are removed via an increase in temperature in a separate environment after the structure is completely fabricated. To understand to what extent these two materials mix during fabrication, two methods of modeling the concentration changes that occur near the interface of the main and support materials have been developed. The …

Furnace Blower Electricity: National And Regional Savings Potential, Florida Solar Energy Center, Victor Franco

FSEC Energy Research Center®

Currently, total electricity consumption of furnaces is unregulated, tested at laboratory conditions using the DOE test procedure, and is reported in the GAMA directory as varying from 76 kWh/year to 1,953 kWh/year. Furnace blowers account for about 80% of the total furnace electricity consumption and are primarily used to distribute warm air throughout the home during furnace operation as well as distribute cold air during air conditioning operation. Yet the furnace test procedure does not provide a means to calculate the electricity consumption during cooling operation or standby, which account for a large fraction of the total electricity consumption. Furthermore, …

Nightcool: A Nocturnal Radiation Cooling Concept, Florida Solar Energy Center, Danny Parker

FSEC Energy Research Center®

An experimental evaluation has been conducted on a night sky cooling system designed to substantially reduce space cooling needs in homes in North American climates. The system uses a sealed attic covered by a highly conductive metal roof (a roof integrated radiator) which is selectively linked by air flow to the main zone with the attic zone to provide cooling - largely during nighttime hours. Available house mass is used to store sensible cooling. Currently, the system's capability for solar dehumidification with minimal electricity input is demonstrated.

How Energy Efficient Are Modern Dishwashers?, Florida Solar Energy Center, David Hoak

FSEC Energy Research Center®

We present measurements of three recent vintage dishwashers of very different efficiencies showing that while they are substantially more efficient than older dishwashers, those tested will still use electric resistance elements for supplemental heat, even when supplied by solar water heating systems producing very hot water. We did find the DOE test results provide a reasonable guide to comparative performance, but suggest improvements that will make them more representative. We also identify a variety of influences on efficiency and performance to reduce dishwasher energy use.

Very Low Energy Homes In The United States: Perspectives On Performance From Measured Data, Florida Solar Energy Center, Danny Parker

FSEC Energy Research Center®

We present measured annual performance data from a dozen recent-vintage very low energy homes in North America. Many of the designs combine greater energy efficiency with solar electric photovoltaic power in an attempt to create Zero Energy Homes (ZEH). We also provide measured data from the first home constructed to the German Passivhaus standard in the United States. Several projects either exceeded or come very close to true net zero energy when evaluated over a year.

The data indicate that very low energy use buildings can very readily be achieved in North America. Annual energy use half that or less …

A Nonlinear Finite Element Model Of Cartilage Growth, Andrew Davol, Michael S. Bingham, Robert L. Sah, Stephen M. Klisch

Mechanical Engineering

The long range objective of this work is to develop a cartilage growth finite element model (CGFEM), based on the theories of growing mixtures that has the capability to depict the evolution of the anisotropic and inhomogeneous mechanical properties, residual stresses, and nonhomogeneities that are attained by native adult cartilage. The CGFEM developed here simulates isotropic in vitro growth of cartilage with and without mechanical stimulation. To accomplish this analysis a commercial finite element code (ABAQUS) is combined with an external program (MATLAB) to solve an incremental equilibrium boundary value problem representing one increment of growth. This procedure is repeated …