Mechanical Engineering Commons^™

Internally Constrained Mixtures Of Elastic Continua, Stephen M. Klisch

Mechanical Engineering

A treatment of internally constrained mixtures of elastic continua at a common temperature is developed. Internal constraints involving the deformation gradient tensors and the common mixture temperature are represented by a constraint manifold, and an internally constrained mixture of elastic continua is associated with each unique equivalence class of unconstrained mixtures. The example of intrinsic incompressibility of each constituent first proposed by Mills is discussed.

Simtrainer: A Management Training Tool, Wade Stark, Sema E. Alptekin

Industrial and Manufacturing Engineering

Abstract published of poster paper presented at conference.

Collaborative Undergraduate Research, Hamid Davoodi, Frederick Just, Ali Saffar, Mohammad Noori, William W. Durgin

Office of the Provost Scholarship

A joint undergraduate research project between University of Puerto Rico at Mayagüez (UPRM) and Worcester Polytechnic Institute (WPI) started four years ago. Each year a group of students, varying between six and ten, from WPI will come to Puerto Rico to work with a group of students, varying from six to ten, from UPRM on a well defined research project. Although the topics of the projects have been different but all follow the same goal, Vibration Control of Structures by Utilizing Shape Memory Alloys. Each year the project starts on January and ends on May. Both groups of the students …

An Evaluation Of Ploughing Models For Orthogonal Machining, Daniel J. Waldorf, Richard E. Devor, Shiv G. Kapoor

Industrial and Manufacturing Engineering

An analytical comparison is made between two basic models of the flow of workpiece material around the edge of an orthogonal cutting tool during steady-state metal removal. Each has been the basis for assumptions in previous studies which attempt to model the machining process, but no direct comparison had been made to determine which, if either, is an appropriate model. One model assumes that a separation point exists on the rounded cutting edge while the other includes a stable build-up adhered to the edge and assumes a separation point at the outer extreme of the build-up. Theories of elastic-plastic deformation …

Scheduling Semiconductor Device Test Operations On Multihead Testers, Tali Freed, Robert C. Leachman

Industrial and Manufacturing Engineering

Past attempts to devise scheduling methods for the device test operations of semiconductor manufacturing firms fail to address a significant characteristic of multiple-head test systems—the dependency of processing rates on the lots processed simultaneously on the testers. Since the problem has never been modeled accurately in the scheduling literature, feasibility and performance of previously proposed scheduling methodologies for multihead testers may not be accurately assessed. In this paper, we describe the multihead tester scheduling problem, present an enumeration solution procedure, and illustrate the problems of previously suggested tester scheduling algorithms.

Gauge Repeatability & Reproducibility Study For A 3-D Solder Paste Inspection System, Jianbiao Pan, Gregory L. Tonkay, Robert H. Storer, Ronald M. Sallade, David J. Leandri

Industrial and Manufacturing Engineering

Due to the increased use of Ball Grid Arrays (BGAs) and fine pitch and ultra fine pitch Quad Flat Packages (QFPs), there is a dramatic increase in demand for solder paste inspection after the stencil printing process. The important response variables of the printing process are deposited solder paste volume, area, height and position. To identify and remove defects at the earliest possible process step, a 3-D solder paste inspection system should be used to monitor solder paste deposited on all pads on every board before component placement. An example is a fully automatic laser-based 3-D triangulation solder paste inspection …

Critical Variables Of Solder Paste Stencil Printing For Micro-Bga And Fine Pitch Qfp, Jianbiao Pan, Gregory L. Tonkay, Robert H. Storer, Ronald M. Sallade, David J. Leandri

Industrial and Manufacturing Engineering

Stencil printing continues to be the dominant method of solder deposition in high volume surface mount assembly. Control of the amount of solder paste deposited is critical for fine pitch and ultra-fine pitch SMT assembly. The process is still not well understood as indicated by the fact that industry reports 52-71% of SMT defects are related to the solder paste stencil printing process. The purpose of this paper is to identify the critical variables that influence the deposited solder paste volume, area, and height. An experiment was conducted to investigate the effects of relevant process parameters on the amount of …

Application Of A Fiber-Reinforced Continuum Theory To Multiple Deformations Of The Annulus Fibrosus, Stephen M. Klisch, Jeffrey C. Lotz

Mechanical Engineering

Accurate tissue stress predictions for the annulus fibrosus are essential for understanding the factors that cause or contribute to disc degeneration and mechanical failure. Current computational models used to predict in vivo disc stresses utilize material laws for annular tissue that are not rigorously validated against experimental data. Consequently, predictions of disc stress resulting from physical activities may be inaccurate and therefore unreliable as a basis for defining mechanical–biologic injury criteria. To address this need we present a model for the annulus as an isotropic ground substance reinforced with two families of collagen fibers, and an approach for determining the …

Screen Printing Process Design Of Experiments For Fine Line Printing Of Thick Film Ceramic Substrates, Jianbiao Pan, Gregory L. Tonkay, Alejandro Quintero

Industrial and Manufacturing Engineering

Screen printing has been the dominant method of thick film deposition because of its low cost. Many experiments in industry have been done and many models of the printing process have been developed since the 1960's. With a growing need for denser packaging and a drive for higher pin count, screen printing has been refined to yield high resolution prints. However, fine line printing is still considered by industry to be difficult. In order to yield high resolution prints with high first pass yields and manufacturing throughput, the printing process must be controlled stringently.

This paper focuses on investigating the …

Industrial Engineering Made Simple, Deena Daggett, Sema E. Alptekin

Industrial and Manufacturing Engineering

Many high school students these days do not quickly recognize or identify Industrial Engineering (IE) procedures, practices, and products. Recruitment of qualified students into IE programs requires continuous planning, publicizing, and networking. Traditional recruitment efforts have included high school visits, brochures & flyers, and university-sponsored workshops. However, these techniques have only achieved mediocre success. Currently, a need exists for new promotional materials that utilize visual tools and provide a “hands-on” approach. We have developed several exercises that successfully introduce IE. Two such exercises are explained in this paper. The first exercise demonstrates the differences between Assembly line and Cellular Manufacturing …

Worn Tool Forces Based On Ploughing Stresses, Daniel Waldorf, Shiv G. Kapoor, Richard E. Devor

Industrial and Manufacturing Engineering

Recent work in modeling of the ploughing mechanism in basic metal machining may provide a means of estimating the additional forces to be expected when cutting with a worn tool. The results predict the rubbing stresses due to the finite radius of an unworn tool edge. Since an unworn tool can be thought of as a worn tool with a wear land width VB = 0, these stresses can make up part of a strategy for predicting the additional forces incurred by a worn tool. This paper develops a wear model by proposing a technique for utilizing the stresses predicted …

A Compensated Acoustic Actuator For Systems With Strong Dynamic Pressure Coupling, Charles Birdsong, Clark J. Radcliffe

Mechanical Engineering

This study improves the performance of a previously developed acoustic actuator in the presence of an acoustic duct system with strong pressure coupling. The speaker dynamics and the acoustic duct dynamics are first modeled separately. The two systems are then coupled, and the resulting system is modeled. A velocity sensor is developed and used in feedback compensation. The resulting speaker system has minimal magnitude and phase variation over a 20–200 Hz bandwidth. These conclusions are verified through experimental results.