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Combined Stressors In Reliability Failure Modes In Flip-Chip Electronic Packaging, Mahsa Montazeri

Graduate Theses and Dissertations

The trend toward miniaturization of electronic devices to fulfill Moore’s law introduces new reliability concerns to the electronic packaging process while worsening existing primary challenges. In solder interconnect specifically, temperature cycling is one of the prominent failure threats. However, with further downscaling of the flip-chip solder connections, electromigration also present a precarious failure mode in these interconnects. On the other hand, understanding the degradation mechanism in solders is crucial for the power electronic products' reliability considering the industrial tendency to replace wirebonds with solder attachment while improving the current carry capacity. This dissertation utilizes FEA simulation and an experimental approach …

Mission Profile Effects On Automotive Drivetrain Electronics Reliability: Modeling And Mitigation, Bakhtiyar Mohammad Nafis

Graduate Theses and Dissertations

The reliability of electronic devices is dependent upon the conditions to which they are subject. Temperature variations coupled with differences in thermal expansion between bonded materials results in thermomechanical stresses to build up, which can instigate failure in the interconnects or other critical regions. With the move towards electrification in the automotive industry, there is the increasingly important consideration of powertrain electronics reliability, the pertinent conditions being governed by the drive cycle or mission profile of the vehicle. The mission profile determines the power dissipated by the electronic devices, which determines the peak and mean temperature, temperature swing and the …

High Temperature Degradation In Gan-Based Hall Effect Sensors, Alexis Anne Krone

Graduate Theses and Dissertations

This research focuses on understanding the effects of accelerated aging through temperature and environment on novel gallium nitride-based Hall effect magnetic field sensors and determining device reliability under electric vehicle operating conditions. The device reliability was modeled using accelerated aging for the temperatures of 200 °C, 350 °C, 450 °C, and 600 °C under various time steps unique to each temperature and either air, which is identical to operating circumstances, or argon, which would model the hermetic packaging environment. Using a high temperature furnace and oven, devices underwent high temperature storage tests at a chosen temperature and time step. Afterwards, …

Computational Design Of Nonlinear Stress-Strain Of Isotropic Materials, Askhad M.Polatov, Akhmat M. Ikramov, Daniyarbek Razmukhamedov

Chemical Technology, Control and Management

The article deals with the problems of numerical modeling of nonlinear physical processes of the stress-strain state of structural elements. An elastoplastic medium of a homogeneous solid material is investigated. The results of computational experiments on the study of the process of physically nonlinear deformation of isotropic elements of three-dimensional structures with a system of one- and double-periodic spherical cavities under uniaxial compression are presented. The influence and mutual influence of stress concentrators in the form of spherical cavities, vertically located two cavities and a horizontally located system of two cavities on the deformation of the structure are investigated. Numerical …

Electrostatic Levitation: An Elegant Method To Control Mems Switching Operation, Mohammad Mousavi, Mohammad Alzgool, Shahrzad Towfighian

Mechanical Engineering Faculty Scholarship

This paper investigates the characteristics of a micro-switch that uses two side electrodes to open a normally closed switch. The side electrodes surround the xed electrode in the well-known gap-closing electrode configuration. The side electrodes can open a closed switch and be tuned to respond appropriately to outside forces. The combined electrode system dramatically improves the control of a standard gap-closing electrode configuration. In conventional switches, a DC voltage above a certain value closes the switch. To re-open the switch, the voltage difference is reduced to peel o the moving electrode. Currently the contact area is carefully designed to avoid …

A Demand-Supply Matching-Based Approach For Mapping Renewable Resources Towards 100% Renewable Grids In 2050, Loiy Al-Ghussain, Adnan Darwish Ahmad, Ahmad M. Abubaker, Mohammad Abujubbeh, Abdulaziz Almalaq, Mohamed A. Mohamed

Mechanical Engineering Graduate Research

Recently, many renewable energy (RE) initiatives around the world are based on general frameworks that accommodate the regional assessment taking into account the mismatch of supply and demand with pre-set goals to reduce energy costs and harmful emissions. Hence, relying entirely on individual assessment and RE deployment scenarios may not be effective. Instead, developing a multi-faceted RE assessment framework is vital to achieving these goals. In this study, a regional RE assessment approach is presented taking into account the mismatch of supply and demand with an emphasis on Photovoltaic (PV) and wind turbine systems. The study incorporates mapping of renewable …

Test-Retest Reliability And Minimal Detectable Change Of The Computerized Dynamic Posturography Proprio For Adults With Chronic Traumatic Brain Injury, Guilherme Manna Cesar, Thad W. Buster, Judith M. Burnfield

Department of Mechanical and Materials Engineering: Faculty Publications

Purpose: Balance deficits after brain injury, including reactive recovery from unexpected perturbations, can persist well after rehabilitation is concluded. While traditional clinical assessments are practical, the anticipatory nature of the tasks may mask perceptible balance control. Computerized dynamic posturography can directly quantify capacity to respond to unexpected, external perturbations. This study examined the reliability of the computerized dynamic posturography assessment with the device PROPRIO® 4000 in adults with traumatic brain injury and created the minimal detectable change for its standardized test.

Methods: Ten adults (ages 21–55 years) with chronic (average 10 ± 6 years post-injury) severe (loss of consciousness 2–75 …