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Full-Text Articles in Mechanical Engineering

Drop Impact Dynamic Response Study Of Jedec Jesd22-B111 Test Board, Michael Krist, Jianbiao Pan, Andrew Farris, Nicolas Vickers Nov 2008

Drop Impact Dynamic Response Study Of Jedec Jesd22-B111 Test Board, Michael Krist, Jianbiao Pan, Andrew Farris, Nicolas Vickers

Industrial and Manufacturing Engineering

Mobile and handheld electronic devices are prone to being dropped. This drop event may result in failure of solder joints inside these devices. The need for RoHS compliant boards coupled with the demand for reliable electronics has resulted in the development of the JEDEC Standard JESD22-B111 to standardize the method of drop testing surface mount electronic components. However, there has been little study on the effects of additional mass on the board and rigidity of the board on drop test reliability. This paper examines the drop impact dynamic responses of the JEDEC JESD22-B111 board. Of interest are the effects of ...


The Effect Of Ultrasonic Frequency On Gold Wire Bondability And Reliability, Jianbiao Pan, Minh-Nhat Le, Cuong Van Pham Nov 2008

The Effect Of Ultrasonic Frequency On Gold Wire Bondability And Reliability, Jianbiao Pan, Minh-Nhat Le, Cuong Van Pham

Industrial and Manufacturing Engineering

This paper presents a systematic study on the effect of 120KHz ultrasonic frequency on the bondability and reliability of fine pitch gold wire bonding. The study was carried out on a thermosonic ball bonder that is allowed to easily switch between ultrasonic frequency of 60KHz and 120 KHz by changing the ultrasonic transducer and the ultrasonic generator. Bonding parameters were optimized through design of experiment methodology for four different cases: 25.4 μm wire at 60 kHz, 25.4 μm wire at 120 kHz, 17.8 μm wire at 60 kHz, and 17.8 μm wire at 120 kHz. The ...


Board Level Failure Analysis Of Chip Scale Package Drop Test Assemblies, Nicholas Vickers, Kyle Rauen, Andrew Farris, Jianbiao Pan Nov 2008

Board Level Failure Analysis Of Chip Scale Package Drop Test Assemblies, Nicholas Vickers, Kyle Rauen, Andrew Farris, Jianbiao Pan

Industrial and Manufacturing Engineering

This paper presents the failure analysis results of board level drop tests. In this study, the test vehicle was designed according to the requirements of the Joint Electron Device Engineering Council (JEDEC) drop test board. The test vehicle was assembled with 15 chip scale packages (CSPs) each having 228 daisy-chained 0.5 mm pitch solder joints using Sn-3.0 wt% Ag-0.5 wt% Cu (SAC305) lead free solder. Assemblies were drop tested using three different peak accelerations of 900 G, 1500 G, 2900 G, with 0.7 ms, 0.5 ms, and 0.3 ms pulse durations, respectively. Scanning electron ...


Work In Progress - Enhancing Student-Learning Through State-Of-The-Art Systems Level Design And Implementation, Albert A. Liddicoat, Jianbiao Pan, James G. Harris, Dominic J. Dal Bello, Lynne A. Slivovsky Oct 2008

Work In Progress - Enhancing Student-Learning Through State-Of-The-Art Systems Level Design And Implementation, Albert A. Liddicoat, Jianbiao Pan, James G. Harris, Dominic J. Dal Bello, Lynne A. Slivovsky

Industrial and Manufacturing Engineering

The curriculum for undergraduate engineering programs is often partitioned into several courses that are taught in isolation followed by a single culminating senior design or capstone project experience. In the senior design class students being to synthesize the knowledge and skills that they acquired through the engineering curriculum. This paper presents lower and upper division course and curricular changes made to accommodate learning objectives that better prepare students for project-based learning. These learning experiences and skills include: systems level design, experience with state-of-the-art Computer Aided Design (CAD) tools, printed circuit board (PBC) design, design for manufacturability, electronics assembly, project management ...


Alternative Binder Carbide Tools For Machining Superalloys, Daniel J. Waldorf, Michael Stender, Scott Liu, Daniel Norgan Oct 2008

Alternative Binder Carbide Tools For Machining Superalloys, Daniel J. Waldorf, Michael Stender, Scott Liu, Daniel Norgan

Industrial and Manufacturing Engineering

This study examines the performance of a new class of wear-resistant but economical cutting tools produced by varying the binder composition of standard cemented carbide composites. By replacing some or all of the cobalt binder with rhenium and nickel-based superalloy, a stronger composite tool results, potentially capable of machining heat-resistant superalloys at significantly higher cutting speeds. Sample tools with alternative binder were produced and compared to standard tools bound with cobalt only. Turning experiments on Inconel 718 were run to evaluate wear resistance and tool life for several grades. The experimentation also examined the effects of varying the relative proportions ...


A Nonlinear Finite Element Model Of Cartilage Growth, Andrew Davol, Michael S. Bingham, Robert L. Sah, Stephen M. Klisch Aug 2008

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 ...


Regulation Of Immature Cartilage Growth By Igf-I, Tgf- Β 1, Bmp-7, And Pdgf-Ab: Role Of Metabolic Balance Between Fixed Charge And Collagen Network, Anna Asanbaeva, Koichi Masuda, Eugene J-M.A. Thonar, Stephen M. Klisch, Robert L. Sah Aug 2008

Regulation Of Immature Cartilage Growth By Igf-I, Tgf- Β 1, Bmp-7, And Pdgf-Ab: Role Of Metabolic Balance Between Fixed Charge And Collagen Network, Anna Asanbaeva, Koichi Masuda, Eugene J-M.A. Thonar, Stephen M. Klisch, Robert L. Sah

Mechanical Engineering

Cartilage growth may involve alterations in the balance between the swelling tendency of proteoglycans and the restraining function of the collagen network. Growth factors, including IGF-I, TGF-β1, BMP-7, and PDGF-AB, regulate chondrocyte metabolism and, consequently, may regulate cartilage growth. Immature bovine articular cartilage explants from the superficial and middle zones were incubated for 13 days in basal medium or medium supplemented with serum, IGF-I, TGF-β1, BMP-7, or PDGF-AB. Variations in tissue size, accumulation of proteoglycan and collagen, and tensile properties were assessed. The inclusion of serum, IGF-I, or BMP-7 resulted in expansive tissue growth, stimulation of proteoglycan deposition but not ...


Enhancing Student Learning Through State-Of-The-Art Systems Level Design And Implementation: The Development Of A Lower Division Learning Module, James G. Harris, Dominic Dal Bello, Jianbiao Pan, Albert Liddicoat Jun 2008

Enhancing Student Learning Through State-Of-The-Art Systems Level Design And Implementation: The Development Of A Lower Division Learning Module, James G. Harris, Dominic Dal Bello, Jianbiao Pan, Albert Liddicoat

Industrial and Manufacturing Engineering

The Cal Poly/Allan Hancock team is developing a learning module that will allow all lower division engineering students to design, fabricate, assemble, and test an electronic system implemented on a printed circuit board (PCB). All the services necessary to perform this laboratory experiment will be provided with low-cost vendors available on the . The learning module is being developed so that it can be integrated into the existing electrical engineering lower division courses that are required by all engineering students. The laboratory learning module will use operational amplifiers (op amp), resistors, capacitors and other common electronic components to study the ...


Curricular Enhancement To Support Project-Based Learning In Computer And Electrical Engineering, Albert Liddicoat, Jianbiao Pan, James G. Harris, Lynne A. Slivovsky Jun 2008

Curricular Enhancement To Support Project-Based Learning In Computer And Electrical Engineering, Albert Liddicoat, Jianbiao Pan, James G. Harris, Lynne A. Slivovsky

Industrial and Manufacturing Engineering

Undergraduate computer and electrical engineering programs often partition the curriculum into several courses based on related topics taught in isolation. Students are expected to synthesize their knowledge in a senior design project. It is the authors’ experience that students often struggle during their senior design project since they have not gained the appropriate knowledge or mastered necessary skills needed to work on a significant or team-based engineering design project. Specifically, students need to be able to define system requirements, partition the design into subcomponents, design, build, test, and verify that the system requirements have been met. The authors have enhanced ...


A Project-Based Electronics Manufacturing Laboratory Course For Lower-Division Engineering Students, Jianbiao Pan, Albert Liddicoat, James G. Harris, Dominic Dal Bello Jun 2008

A Project-Based Electronics Manufacturing Laboratory Course For Lower-Division Engineering Students, Jianbiao Pan, Albert Liddicoat, James G. Harris, Dominic Dal Bello

Industrial and Manufacturing Engineering

This paper presents a project-based laboratory course on electronics design and manufacturing. The goal of this course is to provide lower-division engineering students a hands-on experience involving actual printed circuit board (PCB) design, layout, fabrication, assembly, and testing. Through project-based learning, students not only learn technical skills in designing and manufacturing an electronic device, but also develop their project management and communication skills early in their course of study at the university. The course outline and examples of the student projects are presented in this paper as well as project evaluations and students’ feedback. This paper also presents the selection ...


Techniques For Developing Large Scale Fuzzy Logic Systems, Jon C. Ervin, Sema E. Alptekin Jun 2008

Techniques For Developing Large Scale Fuzzy Logic Systems, Jon C. Ervin, Sema E. Alptekin

Industrial and Manufacturing Engineering

In this paper, we describe various techniques used to make Intuitionistic Fuzzy Logic Systems amenable to operating on applications with large numbers of inputs. A rule reduction technique known as Combs method is combined with an automated tuning process based on Particle Swarm Optimization. A second stage of tuning on rule weights results in improved performance and further reduction in the size of the rule-base. The entire process has been developed to operate within the Matlab software environment. The technique is tested against the Wisconsin Breast Cancer Database. The use of these tools shows great promise in significantly expanding the ...


A Cartilage Growth Mixture Model With Collagen Remodeling: Validation Protocols, Stephen M. Klisch, Anna Asanbaeva, Sevan R. Oungoulian, Koichi Masuda, Eugene J.-Ma. Thonar, Andrew Davol, Robert L. Sah Jun 2008

A Cartilage Growth Mixture Model With Collagen Remodeling: Validation Protocols, Stephen M. Klisch, Anna Asanbaeva, Sevan R. Oungoulian, Koichi Masuda, Eugene J.-Ma. Thonar, Andrew Davol, Robert L. Sah

Mechanical Engineering

A cartilage growth mixture (CGM) model is proposed to address limitations of a model used in a previous study. New stress constitutive equations for the solid matrix are derived and collagen (COL) remodeling is incorporated into the CGM model by allowing the intrinsic COL material constants to evolve during growth. An analytical validation protocol based on experimental data from a recent in vitro growth study is developed. Available data included measurements of tissue volume, biochemical composition, and tensile modulus for bovine calf articular cartilage (AC) explants harvested at three depths and incubated for 13 days in 20% fetal borine serum ...


Articular Cartilage Tensile Integrity: Modulation By Matrix Depletion Is Maturation-Dependent, Anna Asanbaeva, Johnny Tam, Barbara L. Schumacher, Stephen M. Klisch, Koichi Masuda, Robert L. Sah Jun 2008

Articular Cartilage Tensile Integrity: Modulation By Matrix Depletion Is Maturation-Dependent, Anna Asanbaeva, Johnny Tam, Barbara L. Schumacher, Stephen M. Klisch, Koichi Masuda, Robert L. Sah

Mechanical Engineering

Articular cartilage function depends on the molecular composition and structure of its extracellular matrix (ECM). The collagen network (CN) provides cartilage with tensile integrity, but must also remodel during growth. Such remodeling may depend on matrix molecules interacting with the CN to modulate the tensile behavior of cartilage. The objective of this study was to determine the effects of increasingly selective matrix depletion on tensile properties of immature and mature articular cartilage, and thereby establish a framework for identifying molecules involved in CN remodeling. Depletion of immature cartilage with guanidine, chondroitinase ABC, chondroitinase AC, and Streptomyces hyaluronidase markedly increased tensile ...


Drop Test Reliability Of Lead-Free Chip Scale Packages, Andrew Farris, Jianbiao Pan, Albert Liddicoat, Brian J. Toleno, Dan Maslyk, Dongkai Shangguan, Jasbir Bath, Dennis Willie, David A. Geiger May 2008

Drop Test Reliability Of Lead-Free Chip Scale Packages, Andrew Farris, Jianbiao Pan, Albert Liddicoat, Brian J. Toleno, Dan Maslyk, Dongkai Shangguan, Jasbir Bath, Dennis Willie, David A. Geiger

Industrial and Manufacturing Engineering

This paper presents the drop test reliability of 0.5 mm pitch lead-free chip scale packages (CSPs). Fifteen 0.5 mm pitch CSPs were assembled on a standard JEDEC drop reliability test board with Sn3.0Ag0.5Cu lead-free solder. Eight boards were edge-bonded with a UV-cured acrylic; eight boards were edge- bonded with a thermal-cured epoxy; and twelve boards were assembled without edge bonding. Half of the edge-bonded test boards were subjected to drop tests at a peak acceleration of 1500 G with a pulse duration of 0.5 ms, and the other half subjected to drop tests at a ...


Bioengineering Cartilage Growth, Maturation, And Form, Gregory M. Williams, Stephen M. Klisch, Robert L. Sah May 2008

Bioengineering Cartilage Growth, Maturation, And Form, Gregory M. Williams, Stephen M. Klisch, Robert L. Sah

Mechanical Engineering

Cartilage of articular joints grows and matures to achieve characteristic sizes, forms, and functional properties. Through these processes, the tissue not only serves as a template for bone growth but also yields mature articular cartilage providing joints with a low-friction, wear-resistant bearing material. The study of cartilage growth and maturation is a focus of both cartilage biologists and bioengineers with one goal of trying to create biologic tissue substitutes for the repair of damaged joints. Experimental approaches both in vivo and in vitro are being used to better understand the mechanisms and regulation of growth and maturation processes. This knowledge ...


Nonlinear Contact Analysis Of Gear Teeth For Malfunction Diagnostics, D. Kong, J. M. Meagher, C. Xu, X. Wu, Y. Wu Feb 2008

Nonlinear Contact Analysis Of Gear Teeth For Malfunction Diagnostics, D. Kong, J. M. Meagher, C. Xu, X. Wu, Y. Wu

Mechanical Engineering

Gearboxes sustain a variety of faults such as broken-shafts, eroded, broken, or missing teeth, and even broken-cases. Casing mounted accelerometers can detect fault patterns but the signals are complicated and difficult to interpret. This study considers the tooth loading of ideal gears and gears with defects. A large industrial gearbox used in a 12m3 electric mining shovel is modeled. The nonlinear contact mechanics is analyzed to predict the bearing supporting force variation vs. the gear tooth loading after a 3-D CAD model of the gearbox is transferred into multi-body dynamics software. The contact mechanics model of the meshing teeth ...


Cartilage Growth And Remodeling: Modulation Of Balance Between Proteoglycan And Collagen Network In Vitro With Β-Aminopropionitrile, Anna Asanbaeva, Koichi Masuda, Eugene J-M.A. Thonar, Stephen M. Klisch, Robert L. Sah Jan 2008

Cartilage Growth And Remodeling: Modulation Of Balance Between Proteoglycan And Collagen Network In Vitro With Β-Aminopropionitrile, Anna Asanbaeva, Koichi Masuda, Eugene J-M.A. Thonar, Stephen M. Klisch, Robert L. Sah

Mechanical Engineering

Objective

To examine the effect of β-aminopropionitrile (BAPN), an inhibitor of lysyl oxidase, on growth and remodeling of immature articular cartilage in vitro.

Design

Immature bovine articular cartilage explants from the superficial and middle layers were cultured for 13 days in serum-containing medium with or without BAPN. Variations in tissue size, accumulation of proteoglycan and collagen (COL), and tensile mechanical properties were assessed.

Results

The inclusion of serum resulted in expansive tissue growth, stimulation of proteoglycan and COL deposition, and a diminution of tensile integrity. Supplementation of medium with BAPN accentuated this phenotype in terms of a further increase in ...


A Two-Disk Extended Jeffcott Rotor Model Distinguishing A Shaft Crack From Other Rotating Asymmetries, Xi Wu, Jim Meagher Jan 2008

A Two-Disk Extended Jeffcott Rotor Model Distinguishing A Shaft Crack From Other Rotating Asymmetries, Xi Wu, Jim Meagher

Mechanical Engineering

A mathematical model of a cracked rotor and an asymmetric rotor with two disks representing a turbine and a generator is utilized to study the vibrations due to imbalance and side load. Nonlinearities typically related with a “breathing” crack are included using a Mayes steering function. Numerical simulations demonstrate how the variations of rotor parameters affect the vibration response and the effect of coupling between torsional and lateral modes. Bode, spectrum, and orbit plots are used to show the differences between the vibration signatures associated with cracked shafts versus asymmetric shafts. Results show how nonlinear lateral-torsional coupling shifts the resonance ...


Response Of A Warped Flexible Rotor With A Fluid Bearing, Jim Meagher, Xi Wu, Chris Lencioni Jan 2008

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 explored and compared to midspan response, where previous research has concentrated. The model presented also extends earlier work by representing the effect of a nonrigid bearing. Good agreement between the analytical model and experiment demonstrates that the analysis presented ...


Cal Poly Wind Power Research Center, Patrick Lemieux, John Ridgely Jan 2008

Cal Poly Wind Power Research Center, Patrick Lemieux, John Ridgely

Mechanical Engineering

The Wind Power Research Center is being created at California State Polytechnic University in San Luis Obispo, California. This center brings together faculty, undergraduate and graduate students, and industry partners to conduct applied research and education in support of the wind power industry. Particular emphasis is given to research which serves the needs of manufacturers of smaller wind turbines, and to educating engineers who are well trained to work in all segments of the wind power industry.