Mechanical Engineering Commons^™

Greedy Algorithm For Disassembly Line Scheduling, Seamus M. Mcgovern, Surendra M. Gupta

Seamus McGovern

Remanufacturing, recycling, and disposal recovery operations require the performance of disassembly activities. The disassembly line is the best choice for automated disassembly of returned products, however, finding the optimal balance is computationally intensive with exhaustive search quickly becoming prohibitively large. In this paper, a greedy algorithm is presented for obtaining optimal or near-optimal solutions to the disassembly line balancing problem. The greedy algorithm is a first-fit decreasing algorithm further enhanced to preserve precedence relationships. The algorithm seeks to minimize the number of workstations while accounting for hazardous and high demand components. A hill-climbing heuristic is then developed to balance the …

Reviving The U.S. Rail And Transit Industry: Investments And Job Creation, Joan Fitzgerald, Lisa Granquist, Ishwar Khatiwada, Joe Mclaughlin, Michael Renner, Andrew Sum

Ishwar Khatiwada

No abstract provided.

On-Line Monitoring Of Engine Health Through The Analysis Of Contaminants In Engine Lubricant, Hamid R. Aghayan

Electronic Thesis and Dissertation Repository

Monitoring automobile liquids, such as engine lubricants, has received increasing attention recently mainly due to environmental and safety legislation, coat saving measures, and customer demand.

Literature review in monitoring engine lubricant condition indicates systems approach, an intellectual discipline method to address complex problem, has never been used to monitor engine performance and health through the engine sub-systems such as lubricant system. The literature review also points toward deficiency in considering lubricant as a source of information for engine performance evaluation, and lack of understanding of engine lubricant as a medium with random properties.

Engine lubricant condition reflects the state of …

Slamming Induced Dynamic Response Of A Floating Structure, Mohammad Ali Lotfollahi-Yaghin1, Mehdi Rastgar, Hamid Ahmadi

Journal of Marine Science and Technology

Study of the slamming phenomenon is one of the most important branches of the floating structure dynamics. Experimental study of the floating structure dynamics can be very expensive because it requires a long wave flume and a moving model. Hence, numerical methods are considered to be very useful and efficient tools for modeling and dynamic analysis of floating structures. In the present paper, slamming induced impulsive loads are investigated firstly. Afterwards, dynamic response of a barge under the slamming excitation is studied, and the natural frequencies and mode shapes are determined, using the FE software package, ANSYS. Critical cross sections …

Constructing The Comprehensive Subsurface Structure Of Lanyang Plain, Chih-Hao Hsu, Sao-Jeng Chao, Shuh-Gi Chern, Howard Hwang

Journal of Marine Science and Technology

This study presents an integral approach to construct a comprehensive subsurface structure of Lanyang Plain. It is well known that geophysicists and engineers use different techniques to investigate the subsurface structure, and each of these techniques has its own advantages. Therefore, in this study, the excellent results from these two fields are selected and combined to provide a comprehensive profile of the subsurface structure of Lanyang Plain. In this study, the subsurface information on nine recording stations and digital boundary lines of Lanyang Plain based on the digital geologic map published by the Central Geological Survey are utilized to create …

Application Of Parametric Nurbs Geometry To Mode Shape Identification And The Modal Assurance Criterion, Evan D. Selin

Theses and Dissertations

The dynamic characteristics of a part are highly dependent on geometric and material properties of the part. The identification and tracking of vibrational mode shapes within an iterative design process becomes difficult and time consuming due to the frequently changing part definition. Currently, visual inspection of analysis results is used as the means to identify the shape of each vibrational mode determined by the modal analysis. This thesis investigates the automation of the mode shape identification process through the use of parametric geometry and the Modal Assurance Criterion. Displacement results from finite element modal analysis are used to create parametric …

Method For The Simulated Layup Of Composite Fabrics, David M. Christensen

Theses and Dissertations

Due to the complexity of designing advanced composite parts, many software tools have been developed to aid the designer and reduce design cycle time. Draping is one of those tools and is used to predict the fiber angles throughout the part. This application of draping is to simulate the actual hand layup process that a technician would go through while creating a multi-layered laminate composite part. This method is the first to use plies as an underlying surface for draping instead of just using an offset mold surface. This method can visualize full 3D ply geometry taking into account the …

Reviving The U.S. Rail And Transit Industry: Investments And Job Creation, Joan Fitzgerald, Lisa Granquist, Ishwar Khatiwada, Joe Mclaughlin, Michael Renner, Andrew Sum

Andrew Sum

No abstract provided.

An Experimental Investigation On The Flow Behaviour In A Transpired Air Collector, David Greig

Electronic Thesis and Dissertation Repository

An experimental investigation of the flow dynamics in a transpired air collector channel with a corrugated surface is presented. Particle image velocimetry (PIV) was used to obtain twodimensional velocity fields to compare the effects of surface heating on the flow for five flow rates. Mean velocity and turbulent property profiles are presented and compared. Proper orthogonal decomposition and wavenumber spectrum analyses were also conducted to investigate the underlying interactions between the turbulent structures that comprise the complex flow behaviour observed in corrugated flows. Results show that the corrugated waveform was the primary source of turbulence at all flow rates and …

Pricing Of End-Of-Life Items With Obsolescence, Srikanth Vadde, Sagar V. Kamarthi, Surendra M. Gupta

Sagar Kamarthi

Variability in the inflow of end-of-life (EOL) products and fluctuating inventory levels often make the processing of EOL products an economically risky operation for product recovery facilities (PRFs). Choosing an appropriate pricing policy can enhance the performance of PRFs by methodically clearing their inventory and increasing profits. This work presents two pricing models to counter the prospect of product obsolescence that can happen either gradually or suddenly. Product obsolescence can cause demand drop and inventory pile up, both of which could dent the revenues of PRFs. In the first model, gradual obsolescence and environmental regulations that limit the disposal quantity …

Reviving The U.S. Rail And Transit Industry: Investments And Job Creation, Joan Fitzgerald, Lisa Granquist, Ishwar Khatiwada, Joe Mclaughlin, Michael Renner, Andrew Sum

Joan Fitzgerald

No abstract provided.

Acoustic Emission Detection Of Metals And Alloys During Machining Operations, Jameson K. Nelson

Purdue Polytechnic Masters Theses

Nelson, Jameson K. M.S., Purdue University, May 2012. Acoustic Emission Detection of Metals and Alloys During Machining Operations. Major Professor: Rodney G. Handy.

Practical correlation between material deformation attributes and theoretical concepts of machining has proven difficult to attain. The purpose of this study was to further explore trends and relationships using acoustic emission detection of materials undergoing single-point lathe turning machine processes. The majority of machining experiments that incorporate acoustic emissions focuses on tool degradation for the purposes of optimizing consumables required to manufacture mechanical devices. Experiments were implemented varying recording location, mechanical barrier condition, and machine parameters. The …

Model-Based Systems And Methods For Analyzing And Predicting Outcomes Of Vascular Interventions And Reconstructions, Yuris A. Dzenis, Alexey Kamenskiy, Iraklis I. Pipinos, Jason N. Mactaggart

Department of Mechanical and Materials Engineering: Faculty Publications

Systems and methods for analyzing and predicting treatment outcomes of medical procedures such as vascular interventions and reconstructions are disclosed. An illustrative system for analyzing and predicting therapeutic outcomes of medical procedures comprises a relational database configured for classifying and storing patient specific input data for multiple patients, a fluid-solid interaction biomechanical model configured for performing a biomechanics simulation and generating biomechanics data, and a graphical user interface.

Optically Driven Ph Gradient Generator Based On Self-Assembled Proton Pumps For Activating Hydrogel Microactuators, Khaled M. Al-Aribe

Electronic Thesis and Dissertation Repository

This dissertation presents a new approach for developing a biologically inspired photo-electro-chemo-mechanical microactuator by exploiting the ion pumping characteristics of bacteriorhodopsin (bR) proton pumps and the pH sensitivity of smart hydrogels. The ultimate goal of this project is to prove the viability of integrating bR monolayer into novel actuation applications using molecular level architectures. To accomplish this, the bR proton pumps are molecularly labelled, organized, and directionally immobilized on Au-coated substrate, and then integrated with pH sensitive hydrogel. When responding to an incident light beams, the internal proton pumping mechanism is mathematically modeled for quantifying the processing of the photonic …

Us Patent 8,149,079: Magnetically Levitated Mount, Sanza Kazadi

Sanza Kazadi

Exact Stability Analysis Of Neutral Systems With Cross-Talking Delays, Nejat Olgac, Tomáš Vyhlídal, Rifat Sipahi

Rifat Sipahi

The stability of neutral systems with two cross-talking delays is investigated using the method of cluster treatment of characteristic roots (CTCR). here are two main outcomes of this study: (a) Generation of the well-known delay stabilizability condition as a by-product of the CTCR procedure. This is achieved by a small delay stability treatment over the system. We also demonstrate for the delay-stabilizable systems the exact bounds of the stability regions in the domain of the delays. (b) Validation of these stability regions using an alternative point-wise algorithm, which computes the right-most roots of the characteristic quasi-polynomial.

Analytical Stability Study Of A Deterministic Car Following Model Under Multiple Delay Interactions, Rifat Sipahi, Silviu-Iulian Niculescu

Rifat Sipahi

Analytical stability study of some deterministic car following models under time-delay influences is presented and various case studies are demonstrated. Interestingly, for some control law deployed by human drivers, more than one stability interval in the domain of time delay is revealed. Physical interpretations along with comparisons conclude the study.

A Comparative Survey In Determining The Imaginary Characteristic Roots Of Lti Time Delayed Systems, Rifat Sipahi, Nejat Olgac

Rifat Sipahi

The aim of this study is to offer a comparison of the numerical procedures for an important problem, the determination of purely imaginary characteristic roots of LTITime Delayed Systems (LTI-TDS). This problem, in fact, has a crucial role in assessing the stability of the general class of vector LTI-TDS x = Ax + Bx(t -τ). There are many procedures discussed in the literature for this purpose. Those, which are exact, first determine the complete set of imaginary characteristic roots of the dynamics, as they constitute the only points where stability switching can take place. These approaches are, in fact, some …

Complete Stability Map Of First Order - Two Time Delay Systems With Delay Cross-Talk, Rifat Sipahi, Nejat Olgac

Rifat Sipahi

First order linear time invariant dynamics is taken into account with two delays. A unique feature is included in this study, from the stability perspective: a term that represents the cross-talk between the two delays. This class of systems can be treated by a unique procedure, which is recently developed, known as Cluster Treatment of Characteristic Roots (CTCR). In the text we present several case studies to display the steps and the strengths of CTCR. We also include some comparison results with respect to a cornerstone study (Hale, and Huang, 1993), which gives a wonderful point of reference for this …

Stability Robustness Of Retarded Lti Systems With Single Delay And Exhaustive Determination Of Their Imaginary Spectra, Rifat Sipahi, Nejat Olgac

Rifat Sipahi

In this paper we consider the stability robustness of the general class of vector LTI (linear time invariant) equations with a single delay, $\dot{\bf x}(t) = {\bf A}{\bf x}(t) + {\bf B}{\bf x}(t-\tau)$, ${\bf x} \in {\bf R}^n$. The robustness is against the uncertain, but constant delay, $\tau \in {\bf R}^+$. We first present a set of novel propositions and state that the solution must start from the complete knowledge of imaginary spectra of the system, and the corresponding delays. The propositions claim that such spectra form a set of manageably small number of members, and this number is upper …