Mechanical Engineering Commons^™

Application Of Transformative Learning Theory In Engineering Education, John Chen

Mechanical Engineering

The goal of this work-in-progress is to improve student engagement and learning in courses that form the core of a discipline. Such gateway courses represent critical milestones in a student's academic career and have a strong influence on his or her attitude and future success in engineering. We contend that students who struggle in gateway courses do so because they are having difficulty with conceptual transformation, and this project aims to facilitate this change through the ideas advocated within Transformative Learning Theory. The essential elements of this project include the integration of information technologies, provision of rapid feedback to students …

Crack Growth Induced By Sonic Ir Inspection, John C. Chen, Jacob Kephart, Kyle Lick, William T. Riddell

Mechanical Engineering

We have developed an experiment to study the propagation of laboratory-synthesized fatigue cracks under various controlled conditions during Sonic IR inspection. The experiment provides for good repeatability in testing. The parameters of interest include the initial crack length, load history (stress intensity and load ratio) during crack generation, geometry of the crack, material and also the various conditions involving the ultrasonic excitation source. In general, we find that under typical sonic IR inspection conditions, the initial crack will propagate under sonic IR testing. The crack growth after each inspection event varies and exhibits a distribution in length of propagation. The …

Ultrasonic Method For Aircraft Wake Vortex Detection, Rebecca J. Rodenhiser, William W. Durgin, Hamid Johari

Office of the Provost Scholarship

This paper describes the experimental proof of concept study for an ultrasonic method of wake vortex detection. This new acoustic method uses travel time of acoustic pulses around a closed path to measure the net circulation within the acoustic path. In this application the closed path encloses the vorticity shed from one side of a Piper PA-28 aircraft wing. Magnitude and sign of circulation detected is comparable to the expected circulation generated by the Piper PA-28 test aircraft. This study demonstrates the validity of the acoustic method in detecting aircraft wake vortices. Further investigations and applications using this technique are …

Development Of A Biofidelic 'Legform' Impact Test Device, John Davis, Peter Schuster

Mechanical Engineering

Current EuroNCAP test specifications attempt to predict pedestrian lower limb injury in a lateral impact with a rigid legform test device developed by the UK's TRL (Transportation Research Lab). Research shows that the measurements taken from this device (knee bending angle, knee shear, and upper tibia acceleration) do not necessarily correspond to accurate injury prediction. Recent research suggests that the primary improvement to the current test device would be a flexible legform, or one that has more biofidelity (i.e., simulates actual human lower limb response).

The work presented in this paper first reviews current legforms developed for pedestrian impact testing, …

Investigation Of The Lead-Free Solder Joint Shear Performance, James Webster, Jianbiao Pan, Brian J. Toleno

Industrial and Manufacturing Engineering

Reflow profile has significant impact on solder joint performance because it influences wetting and microstructure of the solder joint. The purpose of this study is to investigate the effects of reflow profile and thermal shock on the shear performance of eutectic SnPb (SnPb) and Sn3.0Ag0.5Cu (SAC305) solder joints. Test boards were assembled with four different sized surface mount chip resistors (1206, 0805, 0603 and 0402). Nine reflow profiles for SAC 305 and nine reflow profiles for SnPb were developed with three levels of peak temperature (12ºC, 22ºC, and 32ºC above solder liquidus temperature, or 230ºC, 240ºC, and 250ºC for SAC …

Synthesis Of Gold Micro- And Nano-Wires By Infiltration And Thermolysis, E.A. Olevsky, X. Wang, E. Bruce, M.B. Stern, S. Wildhack, F. Aldinger

Industrial and Manufacturing Engineering

An approach for synthesizing micro- and nano-sized gold wires by infiltration and thermolysis is investigated. A porous ZrO₂ ceramic preform with aligned pores obtained by unidirectional freezing and freeze-drying is employed as an infiltration template. The sintered porous ZrO₂ preform is then infiltrated by a brushing gold solution. The thermolysis is conducted at 600 °C in air. Micro- and nano-sized gold wires are developed within the walls of the pores after thermolysis. The diameter of the gold wires ranges from several hundred nanometers to several microns.

Investigation Of Coupled Lateral And Torsional Vibrations Of A Cracked Rotor Under Radial Load, Xi Mu, Jim Meagher, Clinton Judd

Mechanical Engineering

A practical cracked rotor model with two disks representing a turbine and generator is studied using a four degree of freedom model; two transverse displacements and two torsional angular displacements. The differential equations of a rotor with a crack, unbalance, and constant radial force are first derived in detail using energy principles. The nonlinearities related with a “breathing” crack are incorporated, which distinguishes this paper from others studying stiffness anisotropy of a rotor with a similar rotor configuration. Through numerical simulations, this paper demonstrates the lateral-torsional coupling that occurs with a shaft crack and predicts torsional critical speed frequencies at …

Response Of A Warped Flexible Rotor With A Fluid Bearing, Jim Meagher, Xi Wu, Chris Lencioni

Mechanical Engineering

A two complex degrees of freedom model is developed and compared to experimental data for various amounts of rotor bow and its orientation to mass imbalance of the rotor. The equation of motion is developed by adding constant forces that rotate with the rotor to a Bently-Muszynska two-mode isotropic rotor model with a plane journal bearing. Diagnostic information discernable from probes at the bearing is emphasized and compared to midspan response where previous research has concentrated. Good agreement between the analytical model and experiment demonstrate that the analysis presented can be useful to diagnose and balance residual shaft bow from …

Backward And Forward Compatibility, Jianbiao Pan, Jasbir Bath, Xiang Zhou, Dennis Willie

Industrial and Manufacturing Engineering

In response to the European Union (EU) Restriction of Hazardous Substances (RoHS) and other countries’ impending lead-free directives, the electronics industry is moving toward lead-free soldering. Total lead-free soldering requires not only lead-free solder paste but also lead-free printed circuit board (PCB) finish and lead-free component/packages. Transitioning tin-lead (SnPb) soldering to totally lead-free soldering is a complex issue and involves movement of the whole electronics industry supply chain. In reality, there is a transition period.

Using Underwater Remotely Operated Vehicles As An Engineering Education Tool, Hong Zhang, John Chen, Eric Constans

Mechanical Engineering

Starting in 2004, the Department of Mechanical Engineering at Rowan University introduced a new tool into its program: Remotely Operated Vehicles (ROVs). The tool is used at different aspects ofeducation. As a coursework project, graduating ME seniors researched, designed, built, competed and reported with underwater ROVs to assess their design skills before heading out to start their careers. It tests a wide range of engineering background in one single project and gauges the soft skills such as teamwork, self-learning, communication and evaluation. As a student research project, a multidisciplinary student team developed a robotic field ROV to help biological scientists …

Effect Of Chromium–Gold And Titanium–Titanium Nitride–Platinum–Gold Metallization On Wire/Ribbon Bondability, Jianbiao Pan, Robert M. Pafchek, Frank F. Judd, Jason B. Baxter

Industrial and Manufacturing Engineering

Gold metallization on wafer substrates for wire/ribbon bond applications requires good bond strength to the substrate without weakening the wire/ribbon. This paper compares the ribbon bondability of Cr-Au and Ti-TiN-Pt-Au metallization systems for an optoelectronic application. Both Chromium and Titanium are used to promote adhesion between semiconductor substrates and sputtered gold films. However, both will be oxidized if they diffuse to the gold surface and result in the degradation of the wire/ribbon bondability. Restoring bondability by ceric ammonium nitrate (CAN) etch was investigated. Experiments were conducted to investigate the effect of Cr-Au and Ti-TiN-Pt-Au, annealing, and CAN etch processes, on …

Investigation Of The Lead-Free Solder Joint Shear Performance, James Webster, Jianbiao Pan, Brian J. Toleno

Industrial and Manufacturing Engineering

Reflow profile has significant impact on solder joint performance because it influences wetting and microstructure of the solder joint. The purpose of this study is to investigate the effects of reflow profile and thermal shock on the shear performance of eutectic SnPb (SnPb) and Sn3.0Ag0.5Cu (SAC305) solder joints. Test boards were assembled with four different sized surface mount chip resistors (1206, 0805, 0603 and 0402). Nine reflow profiles for SAC 305 and nine reflow profiles for SnPb were developed with three levels of peak temperature (12ºC, 22ºC, and 32ºC above solder liquidus temperature, or 230ºC, 240ºC, and 250ºC for SAC …

Integrating Design Throughout The Mechanical Engineering Curriculum: A Focus On The Engineering Clinics, Krishan Bhatia, Tirupathi R. Chandrupatla, John C. Chen, Eric Constans, Jennifer A. Kadlowec, Anthony J. Marchese, Paris Von Lockette, Hong Zhang

Mechanical Engineering

At Rowan University, we have infused design into the curriculum through an eight-semester course sequence called the Engineering Clinic. Through this experience students learn the art and science of design in a multidisciplinary team environment. While many engineering programs currently include a Capstone Design course taken near the end of the college career to meet the design needs, Engineering Clinic at Rowan allows students to hone their design skills throughout their four-year career. This paper will describe in further detail the objectives and execution of each year in the design sequence, types of projects and how the Clinics complement traditional …

Estimation Of Liquidus Temperature When Snagcu Bga/Csp Components Are Soldered With Snpb Paste, Jianbiao Pan

Industrial and Manufacturing Engineering

Recently, the soldering of lead-free components with SnPb paste, or lead-free backward compatibility, is becoming a hot topic. One of the major challenges in backward compatibility assembly is the development of a right reflow profile for the soldering of SnAgCu Ball Grid Array (BGA)/Chip Scale Package (CSP) components with SnPb paste. If the SnAgCu reflow profile is used, the reflow temperature may be too high for other SnPb components in the same board during assembly according to the component rating per IPC/JEDEC J-STD-020C. In addition, the flux in SnPb solder paste may not function properly in such a high reflow …

A Comparative Study Of Various Loss Functions In The Economic Tolerance Design, Jehnan Pan, Jianbiao Pan

Industrial and Manufacturing Engineering

Engineering tolerance design plays an important role in modern manufacturing. In this paper, the Kapur's model was modified so that the economic specification limits for both symmetric and asymmetric losses can be established. Three different loss functions: (1) Taguchi's quadratic loss function; (2) Inverted Normal Loss Function; (3) Revised Inverted Normal Loss Function are compared in the economic tolerance design. The relationships between the three loss functions and process capability indices for symmetric tolerance are established. The results suggest that the revised inverted normal loss function be used in determination of economic specification limits.

Student Competitions - The Benefits And Challenges, Peter Schuster, Andrew Davol, Joseph Mello

Mechanical Engineering

Intercollegiate design competitions are a popular means to engage students in design activities that extend beyond the curriculum. When students gather around a project in their spare time and use their classroom skills to design, build, and test a product for an intercollegiate competition, something amazing happens: They develop a passion for engineering. This paper discusses the key benefits to engineering undergraduate students that flow from involvement in a team design competition. Advisor involvement plays a key role in both project success and student learning throughout the process. Different approaches to advising student competition teams are compared. Specific examples are …

Research In The Undergraduate Environment, Charles Birdsong, Peter Schuster

Mechanical Engineering

The benefits of research experiences for undergraduates are significant. For many faculty, these were the experiences that convinced us to pursue further education and a career in academia. However, performing research at an undergraduate institution carries with it certain challenges. In traditional research institutions, doctoral students perform most of the research activities, led by the faculty. These students have completed at least their undergraduate courses and can be expected to remain on the research team for four to six years. In contrast, at an undergraduate institution students may start in the group with only one or two engineering courses completed, …

Plotting A Bright Future For Manufacturing Education: Results Of A Brainstorming Session, Daniel Waldorf, Sema E. Alptekin, Robert Bjurman

Industrial and Manufacturing Engineering

Manufacturing industries worldwide have undergone dramatic changes in recent years and now demand more from graduating manufacturing engineers. The effects of globalization have forever changed the parameters for success in manufacturing. Our educational institutions must respond to these changes with innovation. That agenda formed the basis for a special SME/CIRP international conference on manufacturing engineering education called “Looking Forward: Innovations in Manufacturing Engineering Education,” held in San Luis Obispo, California, June 22-25, 2005. At the meeting, manufacturing education professionals from around the world came together to share their own innovative ideas and to brainstorm ways to shape the future of …

A Bimodular Theory For Finite Deformations: Comparison Of Orthotropic Second-Order And Exponential Stress Constitutive Equations For Articular Cartilage, Stephen M. Klisch

Mechanical Engineering

Cartilaginous tissues, such as articular cartilage and the annulus fibrosus, exhibit orthotropic behavior with highly asymmetric tensile–compressive responses. Due to this complex behavior, it is difficult to develop accurate stress constitutive equations that are valid for finite deformations. Therefore, we have developed a bimodular theory for finite deformations of elastic materials that allows the mechanical properties of the tissue to differ in tension and compression. In this paper, we derive an orthotropic stress constitutive equation that is second-order in terms of the Biot strain tensor as an alternative to traditional exponential type equations. Several reduced forms of the bimodular second-order …

Current Trends In Bumper Design For Pedestrian Impact, Peter J. Schuster

Mechanical Engineering

Worldwide, the pace of development in pedestrian countermeasures is increasing rapidly. To better understand the state of the art in bumper design for pedestrian impact, a survey of literature and patents has been performed. Two general approaches to reducing the severity of pedestrian lower limb impacts were identified: (a) Provide cushioning and support of the lower limb with a bumper and a new lower stiffener, or (b) Use the bumper as a platform for impact sensors and exterior airbags. This study focused on the first approach. Excluding bumper sensors, airbags, and non-design-related articles, a total of 130 relevant technical articles …

An Investigation On The Importance Of Material Anisotropy In Finite-Element Modeling Of The Human Femur, Ryan Krone, Peter Schuster

Mechanical Engineering

Detailed finite element modeling of the human body offers a potential major enhancement to the prediction of injury risk during vehicle impacts. Currently, vehicle crash safety countermeasure development is based on a combination of testing with established anthropomorphic test devices (i.e., ATD or dummy) and a mixture of multi-body (dummy) and finite element (vehicle) modeling. If a relatively simple finite element model can be developed to capture additional information beyond the capabilities of the multi-body systems, it would allow improved countermeasure development through more detailed prediction of performance.

A simpler finite element model of human bones could be developed if …

Test Methods And Results For Sensors In A Pre-Crash Detection System, Charles Birdsong, Peter Schuster, John Carlin, Daniel Kawano, William Thompson

Mechanical Engineering

Automobile safety can be improved by anticipating a crash before it occurs and thereby providing additional time to deploy safety technologies. This requires an accurate, fast and robust pre-crash sensor that measures telemetry, discriminates between classes of objects over a range of conditions, and has sufficient range and area of coverage surrounding the vehicle. The sensor must be combined with an algorithm that integrates data to identify threat levels. No one sensor provides adequate information to meet these diverse and demanding requirements. However the requirements can be met with an optimal combination of multiple types of sensors. Previous work considered …

Processing Model For Tungsten Powders And Extention To Nanoscale Size Range, Randall M. German, J. Ma, X. Wang, E. Olevsky

Industrial and Manufacturing Engineering

Nanoscale tungsten powders promise access to very hard, strong and wear resistant materials via the press–sinter route. A small particle size changes the response during sintering, requiring lower temperatures and shorter times to attain dense but small grain size structures. On the other hand, oxide reduction and impurity evaporation favour high sintering temperatures and long hold times. Accordingly, press–sinter processing encounters conflicting constraints when applied to small particles. Presented here is an analysis of press–sinter tungsten particle processing to isolate conditions that balance the temperature and size dependent effects. The calculations are pinned by existing data. Opportunities are identified for …

Ultrasonic Method For Aircraft Wake Vortex Detection, Rebecca J. Rodenhiser, William W. Durgin, Hamid Johari

Office of the Provost Scholarship

This paper describes the experimental proof of concept study for an ultrasonic method of wake vortex detection for airport use. This new acoustic method utilizes travel time of acoustic pulses around a closed path to measure the net circulation within the acoustic path. In this application the closed path encloses the vorticity shed from one side of a Piper PA28 aircraft wing. Magnitude and sign of circulation detected is comparable to the expected circulation generated by the Piper PA28 test aircraft. This study demonstrates the validity of the acoustic method in detecting aircraft wake vortices. Further investigations and applications utilizing …

The Effect Of Reflow Profile On Snpb And Snagcu Solder Joint Shear Strength, Jianbiao Pan, Brian J. Toleno, Tzu-Chien Chou, Wesley J. Dee

Industrial and Manufacturing Engineering

Purpose –The purpose of this work is to study the effect of the reflow peak temperature and time above liquidus on both SnPb and SnAgCu solder joint shear strength.

Design/methodology/approach –Nine reflow profiles for Sn3.0Ag0.5Cu and nine reflow profiles for Sn37Pb have been developed with three levels of peak temperature (230°C, 240°C, and 250°C for Sn3.0Ag0.5Cu; and 195°C, 205°C, and 215°C for Sn37Pb) and three levels of time above solder liquidus temperature (30, 60, and 90 s). The shear force data of four different sizes of chip resistors (1206, 0805, 0603, and 0402) are compared across the different …

A Simplified Model For Ploughing Forces In Turning, Daniel Waldorf

Industrial and Manufacturing Engineering

This paper aims to provide experimental data in support of a modified theoretical model for quantifying the effect of cutting tool edge geometry on machining forces. A previously published slip-line model is simplified and extended to the case of turning. Several sets of machining experiments were run with custom-fabricated cutting inserts of varying edge hone radius and chamfer geometry. Cutting forces were measured using a dynamometer during cutting. Results show that varying edge geometry can have a major effect on cutting forces. The developed model effectively captures the edge phenomenon and its effect on cutting forces and also offers a …

Evaluation Of Cost Effective Sensor Combinations For A Vehicle Precrash Detection System, John Carlin, Charles Birdsong, Peter Schuster, William Thompson, Daniel Kawano

Mechanical Engineering

The future of vehicle safety will benefit greatly from precrash detection -the ability of a motor vehicle to predict the occurrence of an accident before it occurs. There are many different sensor technologies currently available for pre-crash detection. However no single sensor technology has demonstrated enough information gathering capability within the cost constraints of vehicle manufacturers to be used as a stand alone device. A proposed solution consists of combining information from multiple sensors in an intelligent computer algorithm to determine accurate precrash information. In this paper, a list of sensors currently available on motor vehicles and those that show …

Optimization Of The Fuzzy Logic Controller For An Autonomous Uav, Jon C. Ervin, Sema E. Alptekin, Dianne J. Deturris

Industrial and Manufacturing Engineering

In this paper, we describe the optimization of membership functions in an application employing a hierarchical Fuzzy Logic Controller. The size of the rule base is made manageable by using a unique formulation, known as Combs method, to help control the problem of ‘exponential rule expansion’. The optimization is performed using a steady state genetic algorithm with a dynamic fitness function. The controller being developed is designed to fly a small, autonomous parafoil, suitable for short-range reconnaissance and land survey applications. The optimization process is performed in the Matlab/Simulink software environment and incorporates fuzzy logic modules developed in the Matlab …

Experimental Investigation Of The Travel-Time Variance Of An Acoustic Wave Propagating Through The Grid-Generated Turbulence, Tatiana A. Andreeva, William W. Durgin

Office of the Provost Scholarship

An experimental technique for the investigation of the behaviour of acoustic wave propagation through a turbulent medium is discussed. The present study utilizes the ultrasonic travel-time technique to diagnose a grid-generated turbulence. Travel-time variance is studied versus mean flow velocity, travel distance and outer turbulence scale. The effect of thermal fluctuations, which result in fluctuations of sound speed, is studied using a heated-grid experiment. Experimental data obtained using ultrasonic technique confirm numerical and theoretical predictions of nonlinear increase of the travel-time variance with propagation distance, which could be connected to the occurrence of caustics. The effect of turbulent intensity on …

Stability Analysis For Forging Of Porous Bodies, Xuan Wang, Eugene Olevsky, Alain Molinari

Industrial and Manufacturing Engineering

The continuum theory of sintering is used for the analysis of the stability of forging of a cylindrical powder specimen. The constitutive properties of the powder material are assumed to follow a power-law creep relationship. Temperature-coupled linear non-uniform stability analyses are carried out. Stability maps are obtained for forging of copper powder components.