Mechanical Engineering Commons^™

Admittance Selection For Planar Force-Guided Assembly For Single-Point Contact With Friction, Shuguang Huang, Joseph M. Schimmels

Mechanical Engineering Faculty Research and Publications

This paper identifies procedures for selecting the appropriate admittance to achieve reliable planar force-guided assembly for single-point frictional contact cases. A set of conditions that are imposed on the admittance matrix is presented. These conditions ensure that the motion that results from contact reduces part misalignment. We show that, for bounded misalignments, if an admittance satisfies the misalignment-reduction conditions at a finite number of contact configurations and a given coefficient of friction /spl mu//sub M/) then the admittance will also ensure that the conditions are satisfied at all intermediate configurations for all coefficients less than /spl mu//sub M/.

Efficient Contact State Graph Generation For Assembly Applications, Feng Pan, Joseph M. Schimmels

Mechanical Engineering Faculty Research and Publications

An important aspect in the design of many automated assembly strategies is the ability to automatically generate the set of contact states that may occur during an assembly task. In this paper, we present an efficient means of constructing the set of all geometrically feasible contact states that may occur within a bounded set of misalignments (bounds determined by robot inaccuracy). This set is stored as a graph, referred to as an Assembly Contact State Graph (ACSG), which indicates neighbor relationships between feasible states. An ACSG is constructed without user intervention in two stages. In the first stage, all hypothetical …

Study Guide For Photovoltaic System Installers And Sample Examination Questions, Florida Solar Energy Center, James Dunlop

FSEC Energy Research Center®

This Study Guide presents some of the basic cognitive material that individuals who install and maintain photovoltaic (PV) power systems should know and understand. This information is intended primarily as a Study Guide to help individuals better prepare for the NABCEP PV installer examination but does not provide all of the materials needed for completing the certification examination. Knowledge of the information presented, knowledge of pertinent sections of the National Electrical Code and appropriate experience and qualifications, are generally required of those applying for and completing the NABCEP certification process. Applicants and certificants are also reminded that local installation codes …

Achieving Airtight Ducts In Manufactured Housing, Florida Solar Energy Center, Janet Mcilvaine

FSEC Energy Research Center®

Data and findings presented here were gathered between 1996 and 2003 during 39 factory visits at 24 factories of six HUD Code home manufacturers interested in improving the energy efficiency their homes. Factory observations typically showed that building a tighter duct system was the most cost effective way to improve the product's energy efficiency.

Utilization Of A Piezoelectric Polymer To Sense Harmonics Of Electromagnetic Torque, Jason Neely, Steven Pekarek, Daniel S. Stutts, Philip Beccue

Mechanical and Aerospace Engineering Faculty Research & Creative Works

In this paper, the use of a piezoelectric polymer material to measure the harmonics of electromagnetic torque produced by a permanent magnet synchronous machine is described. The advantages of the polymer include low cost, durability, and flexibility. In addition, wide-bandwidth sensors are relatively easy to design and couple to drive system hardware for harmonic evaluation or to use in feedback-based control. To illustrate the use of the polymer, the electrical and mechanical properties of three sensors are described. The results of time-domain simulation and hardware experiments are used to validate that the voltage obtained from the sensors is linearly related …

Vibration Based Crack Detection In A Rotating Disk: Part 1—An Analytical Study, Andrew L. Gyekenyesi, Jerzy T. Sawicki, George Y. Baaklini

Mechanical Engineering Faculty Publications

This paper describes the analytical results concerning the detection of a crack in a rotating disk. The concept of the approach is based on the fact that the development of a disk crack results in a distorted strain field within the component. As a result, a minute deformation in the disk’s geometry as well as a change in the system’s center of mass occurs. Finite element analyses were conducted concerning a notched disk in order to define the sensitivity of the method. The notch was used to simulate an actual crack and will be the method utilized for upcoming experiments. …

Business Case For Implementing Two Ergonomic Interventions At An Electric Power Utility, Patricia Seeley, Richard W. Marklin

Mechanical Engineering Faculty Research and Publications

Ergonomics analysis of line workers in the electric power industry who work overhead on utility poles revealed some tasks for which less than 1% of the general population had sufficient strength to perform. During a 2-year study, a large Midwestern US electric utility provided a university with a team of represented workers and management. They evaluated, recommended, and monitored interventions for 32 common line worker tasks that were rated at medium to high magnitude of risk factors for musculoskeletal disorders (MSDs). Two of the recommended ergonomic interventions—the battery-operated press and cutter—were selected by the team as having the greatest potential …

Two Semi-Infinite Interfacial Cracks Between Two Bonded Dissimilar Elastic Strips, Xiangfa Wu, Yuris A. Dzenis, Tian-You Fan

Department of Engineering Mechanics: Faculty Publications

The complex stress intensity factor and energy release rate are obtained for two semi-infinite interfacial cracks between two bonded dissimilar elastic strips with equal thickness under inplane deformations. During the procedure, by means of conformal mapping technique, the mixed boundary-value problem is reduced to a standard Riemann–Hilbert problem, which is further solved in closed-form. In some limiting cases, the present explicit solutions can cover the well-known results in the literature.

Autonomous Vehicle Technologies For Small Fixed Wing Uavs, Derek B. Kingston, Randal Beard, Timothy Mclain, Michael Larsen, Wei Ren

Faculty Publications

Autonomous unmanned air vehicle flight control systems require robust path generation to account for terrain obstructions, weather, and moving threats such as radar, jammers, and unfriendly aircraft. In this paper, we outline a feasible, hierarchal approach for real-time motion planning of small autonomous fixed-wing UAVs. The approach divides the trajectory generation into four tasks: waypoint path planning, dynamic trajectory smoothing, trajectory tracking, and low-level autopilot compensation. The waypoint path planner determines the vehicle's route without regard for the dynamic constraints of the vehicle. This results in a significant reduction in the path search space, enabling the generation of complicated paths …

Development Of A New Apparatus To Measure Flame Spread Through A Free Stratified Fuel/Air Mixture: Numerical Modeling And Experimental Results, Fred Hovermann

Theses and Dissertations

While flame spread through uniform fuel-air mixtures has been widely studied in combustion science, there has been relatively little attention given to the study of non-homogenous, or layered, fuel-air mixtures. However, these systems are common occurrences in such cases as terrestrial fuel spills and fuel leaks in both normal and microgravity. Conducting research on layered fuel-air mixtures and understanding the properties of flame propagation has potential implications for fire safety (both on earth and in space), as well as being of fundamental interest. The main objective behind this study is to determine flame speed, flammability regions, stability limits, and the …

Finite Element Modeling Of A Commuter Category Aircraft Seat Under Crash Loading, David William Bowen

Theses and Dissertations

This thesis describes the development and validation of a finite element model of a commuter aircraft seat under crash loading. In particular, this effort has developed an LS-DYNA model of a Beechcraft 1900C low back passenger seat.

Although air travel is one of the safest forms of transportation, crash-related fatalities do occur even in relatively low severity crashes. Many of these fatalities can be traced to the inability of production seats to absorb crash energy. The goal of this research effort is to develop a computational model of a production aircraft seat as a first step towards the development of …

Synthesis Of Nano/Micro Particles Using Supercritical Method And Particle Characterization, Abhijit Aniruddha Gokhale

Theses

The thesis work consists of the two parts, jet behavior of solvents (ethanol and acetone) and the particle formation using SAS method. In the first part, the study of the effects of process parameters like temperature, pressure, injection velocity and internal diameter of nozzle on liquid jets are studied. The critical pressure for which liquid jet of solvents changes to gas - like jet, is investigated.

In the second part, the experiments are done to study the process of the particle formation using SAS method. Effects of process parameters like pressure, injection velocity of solution, the inner diameter of nozzle …

A Study Of Radiofrequency Cardiac Ablation Using Analytical And Numerical Techniques, Ryan Todd Roper

Theses and Dissertations

Studies on radiofrequency (RF) ablation are often aimed at accurately predicting tissue temperature distributions by numerical solution of the bioheat equation. This thesis describes the development of an analytical solution to serve as a benchmark for subsequent numerical solutions. The solution, which was obtained using integral transforms, has the form of a surface integral nested within another surface integral. An integration routine capable of evaluating such integrals was developed and a C program was written to implement this routine. The surface integration routine was validated using a surface integral with a known analytical solution. The routine was, then, used to …

Incorporating Functionally Graded Materials And Precipitation Hardening Into Microstructure Sensitive Design, Mark Edward Lyon

Theses and Dissertations

The methods of MSD are applied to the design of functionally graded materials. Analysis models are presented to allow the design of compliant derailleur for a case study and constraints are placed on the design. Several methods are presented for relating elements of the microstructure to the properties of the material, including Taylor yield theory, Hill elastic bounds, and precipitation hardening.

Applying n-point statistics to the MSD framework is also discussed. Some results are presented for the information content of the 2-point correlation statistics that follow from the methods used to integrate functionally graded materials into MSD.

For the compliant …

Design And Analysis Of End-Effector Systems For Scribing On Silicon, Bennion Rhead Cannon

Theses and Dissertations

This thesis investigates end-effector systems used in a chemomechanical scribing process. Chemomechanical scribing is a method of patterning silicon to selectively deposit a monolayer of material on the surface of the silicon. This thesis details the development of a unique end-effector for chemomechanical scribing using a compliant mechanism solution. The end-effector is developed to scribe lines that have uniform geometry and produce less chipping on the surface of the silicon. The resulting scribing mechanism is passively controlled, has high lateral stiffness, and low axial stiffness. The mechanism is analyzed using the pseudo-rigid-body model and linear-elastic beam method to determine the …

Modeling For The Control Of The Laser Aided Manufacturing Process (Lamp), Mallikharjuna R. Boddu, Vishnu P. Thayalan, Robert G. Landers

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Many state-of-the-art Rapid Prototyping (RP) technologies adopt lasers to fabricate 3-D solid parts by material deposition in layers. The ability of these RP technologies to control the process requires a thorough understanding of the process mechanics. This paper presents the analysis of an analytical, dynamic model explaining the complex phenomenon of Laser Aided Manufacturing Process (LAMP). The equilibrium of the dynamic model is analyzed and dynamic simulations are performed to determine its stability characteristics. This model forms the basis for the real-time control of the LAMP.

Application Of A Diagnostic Tool In Laser Aided Manufacturing Processes, Sashikanth Prakash, Mallikharjuna Rao Boddu, Frank W. Liou

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Lasers play a vital role in producing parts with high dimensional accuracy, strength and quality in today's rapid prototyping industry. In the process of Laser Metal Deposition, many problems are encountered where the part quality does not meet the required standards. This could be due to the nonconformity of control parameters or unnecessary interactions between the control factors. This paper discusses the implementation of Dr. Genichi Taguchiï's optimization techniques using Design of Experiments (DOE) where a series of fractional factorial experiments are performed on the laser deposition process. The results from these experiments are evaluated with respect to the rate …

Process Control Of Laser Metal Deposition Manufacturing -- A Simulation Study, Robert G. Landers

Mechanical and Aerospace Engineering Faculty Research & Creative Works

The laser metal deposition process is a rapid manufacturing operation capable of producing functional prototypes with complex geometries and thin sections. This process inherently contains significant uncertainties and, therefore, extensive experimentation must be performed to determine suitable process parameters. An alternative is to directly control the process on-line using feedback control methodologies. In this paper, a nonlinear control strategy based on feedback linearization is created to automatically regulate the bead morphology and melt pool temperature. Extensive simulation studies are conducted to validate the control strategy.

Mapping Of Ecosystems In Mount Bromo Using Remote Sensing Technology, Bangun Muljo Sukojo

Makara Journal of Technology

Mapping of Ecosystems in Mount Bromo Using Remote Sensing Technology. Covered land analyses of Landsat image have been done to get ecosystem types and map in Mount Bromo region using remote sensing technology. There are nine types of ecosystems in Mount Bromo region, i.e. primary forest, secondary forest, lake, crater, sands, uncovered land, underbrush, dry-field and residence. Distribution of rock analysis has also been done by comparing the manual image interpretation with geological map. The results were coorelated with the digital image interpretation to find rock distribution map which can be useful to get the information about water reservation potencial …

Capacity Of High-Speed Powerline Communication In Vehicles, Deny Hamdani, Ery Safrianti

Makara Journal of Technology

Powerline Communication (PLC) Systems intents to use the mains network in vehicles for high-speed data transmission. Carrier frequencies in the range of MHz are required to establish data rates of some megabits per second. In this paper, typical reference channels extracted from channel measurements are presented and computation results of their capacities according to Shannon’s theorem are presented. Furthermore, the effect of limitations of frequency range and power spectral density of transmitted signal on achievable capacity is investigated. This paper outlines an assessment for theoretical channel capacity and achievable data rates of vehicular PLC transmission schemes. Finally, EMC (Electromagnetics Compatibility) …

Diffuser Optimation At Exhaust System With Catalytic Converter For 110 Cc Mopet With Fluid Flow Cfd Simulation, Tresna P. Soemardi, Ahmad Indra Siswantara, Erwin Erwin

Makara Journal of Technology

Diffuser Optimation at Exhaust System with Catalytic Converter for 110 cc Mopet with Fluid Flow CFD Simulation. CFD simulation used to get behavior of exhaust gas through catalyst, this result will be used to optimize geometry form to perform uniform stream distribution to catalyst, and CFD Simulation will used to analyze backpressure that happened at the model.

The Study On Fluorescence Characteristics Of Chlorella Spp: Ph Influence On Culture, Retno Wigajatri P., Andrianto Handojo, Hendrik Kurniawan, N. B. Prihantini

Makara Journal of Technology

The Study on Fluorescence Characteristics of Chlorella spp: pH Influence on Culture. Experiments for measuring the fluorescence characteristics of Chlorella spp. by using high stability and high repetition rate nitrogen laser of energy 5 mJ with pulse duration of 5 ns have been carried out. The results show that for a cell concentration range from 2,625 cells/ml up to 2,769,000 cells/ml, the fluorescence intensities at pada λ = 687 nm have a linear relationship with the cell concentration. It has been also found that for a 7 days old chlorella culture, the pH variation at the starting culture influenced the …

The Performance Analysis Of A Unicast Network When Two Protocols, Sctp (Stream Control Transmission Protocol) And Tcp (Transmission Control Protocol) Coexist In The Network, Bagio Budiardjo, Michael Thiotrisno

Makara Journal of Technology

This paper elaborates the performance analysis of a unicast network when two protocols, SCTP (Stream Control Transmission Protocol) and TCP (Transmission Control Protocol) coexist in the network. These two protocols are tested using File Transfer Protocol (FTP) and Constant Bit Rate (CBR) based traffic. From the simulations, it could be concluded that SCTP could achieve better throughput compared to TCP in both FTP and CBR based traffic, with sufficiently high fairness index of both intrafairness and interfairness. The increase of simulation time yields to the increase and relatively stable network performance. The increase of the number of sessions of small …

Ultrasound Technique For Prediction Of Statistical Characteristics Of Grid-Generated Turbulence, Tatiana A. Andreeva, William W. Durgin

Office of the Provost Scholarship

Ultrasonic measurement techniques can be used to determine some characteristics of turbulent flows. In this work measurements of the difference in propagation times of ultrasonic waves along two paths are combined with the Kolmogorov (²/₃)-power law to study characteristics of grid-generated turbulence. The paper focuses on ultrasonic measurements of turbulent flow using the travel-time technique. The present research is of interest from two points of view. First, it demonstrates an ultrasonic method of investigation of turbulence, and second, it furthers understanding of the effect of turbulence on sound propagation.

Sufficient Conditions Used In Admittance Selection For Force-Guided Assembly Of Polygonal Parts, Shuguang Huang, Joseph M. Schimmels

Mechanical Engineering Faculty Research and Publications

Admittance control approaches show significant promise in providing reliable force-guided assembly. An important issue in the development of these approaches is the specification of an appropriate admittance control law. This paper identifies procedures for selecting the appropriate admittance to achieve reliable force-guided assembly of planar polyhedral parts for single-point contact cases. A set of conditions that are imposed on the admittance matrix is presented. These conditions ensure that the motion that results from contact reduces part misalignment. We show that, for bounded misalignments, if an admittance satisfies the misalignment-reduction conditions at a finite number of contact configurations, then the admittance …

Volumetric Growth Of Thermoelastic Materials And Mixtures, Stephen M. Klisch, Anne Hoger

Mechanical Engineering

The proteoglycan and collagen constituents of cartilage serve distinct mechanical roles. Changes to the mechanical loading conditions during cartilage growth lead to changes in the concentrations of these molecules and, consequently, the mechanical properties. The main aim of this paper is to present a theory that can describe the mechanical aspects of cartilage growth. The model for cartilage growth is based on a general thermomechanical theory for a mixture of an arbitrary number of growing elastic constituents and an inviscid fluid. Our development of a growth mixture theory is accomplished in two steps. First, the thermodynamics of growing elastic materials …

Learning Real-Time A* Path Planner For Sensing Closely-Spaced Targets From An Aircraft, Jason K. Howlett, Michael A. Goodrich, Timothy W. Mclain

Faculty Publications

This work develops an any-time path planner, based on the learning real-time A* (LRTA*) search, for generating flyable paths that allow an aircraft with a specified sensor footprint to sense a group of closely-spaced targets. The LRTA* algorithm searches a tree of flyable paths for the branch that accomplishes the desired objectives in the shortest distance. The tree of paths is created by assembling primitive turn and straight sections of a specified step size. The operating parameters for the LRTA* search directly influence the running time and path-length performance of the search. A modified LRTA* search is presented that terminates …

Developing A Sensing System For The Measurement Of Oxygen Concentration In Liquid Pb-Bi Eutectic: Quarterly Progress Report (May. 01 – July 31, 2003), Yingtao Jiang, Bingmei Fu, Woosoon Yim

Transmutation Sciences Materials (TRP)

The report for Y01 has been prepared and submitted. The final part of our apparatus, the N3Si4 stirrer, was received by the end of May. The assembly of the apparatus has almost been completed. The control plan for our apparatus has been revised. To run FLUENT, a high-end Unix-based Sun workstation has been acquired. Plan has been made to ship our apparatus to LANL.

Analysis And Design Of Surface Micromachined Micromanipulators For Out-Of-Plane Micropositioning, Kimberly A. Jensen

Theses and Dissertations

This thesis introduces two ortho-planar MEMS devices that can be used to position microcomponents: the XZ Micropositioning Mechanism and the XYZ Micromanipulator. The displacement and force relationships are presented. The devices were fabricated using surface micromachining processes and the resulting mechanisms were tested. A compliant XYZ Micromanipulator was also designed to reduce backlash and binding. In addition, several other MEMS positioners were fabricated and tested: the Micropositioning Platform Mechanism (MPM), the Ortho-planar Twisting Micromechanism (OTM), and the Ortho-planar Spring Micromechanism (OSM).

Development Of Advanced High Temperature Heat Exchangers: Proposal, University Of Nevada, Las Vegas. Research Foundation

Publications (NSTD)

A research team led by the University of Nevada, Las Vegas (UNLV) Research Foundation proposes a project to develop advanced high temperature heat exchangers (HTHX) for hydrogen production and electrical energy conversion from advanced nuclear reactor concepts. This project will also support the development of Generation IV reactors. The research team includes researchers from UNLV, General Atomics (GA), Sandia National Laboratories (SNL), The University of California, Berkeley UCB) and Oak Ridge National Laboratory (ORNL).

The proposed project will be administered by the University of Nevada Las Vegas Research Foundation (UNLVRF). UNLVRF will provide the overall contract administration and is the …