Engineering Commons^™

Rheology Of Cross-Linked Polymers And Polymer Foams: Theory And Experimental Results, John Herman

Wayne State University Dissertations

Typical polymers have a time-dependent response to loading which results in stress relaxation or creep. Models using springs/dashpots or Volterra integrals are capable of predicting the material response, but place little or no emphasis on the reasoning behind the response. This research proposes a microscopic reasoning behind polymer chain movement, while developing a model to predict the creep and stress relaxation of a polymer foam. Based on the theorized slip/stick of polymer chains as they slide past each other, this model successfully predicts the behavior of a PMI polymer foam under tensile loads. This model lends insights into polymer microscopic …

Specialized Inter-Particle Interaction Lbm For Patterned Superhydrophobic Surfaces, Amal Saeed Yagub

Wayne State University Dissertations

SPECIALIZED INTER-PARTICLE INTERACTION LBM FOR PATTERNED SUPERHYDROPHOBIC SURFACES

by

AMAL S. YAGUB

ABSTRACT:

Superhydrophobic surface characteristics are important in many industrial applications, ranging from the textile to the military. It was observed that surfaces fabricated with nano/micro roughness can manipulate the droplet contact angle, thus providing an opportunity to control the droplet wetting characteristics. The Shan and Chen (SC) lattice Boltzmann model (LBM) is a good numerical tool, which holds strong potentials to qualify for simulating droplets wettability. This is due to its realistic nature of droplet contact angle (CA) prediction on flat smooth surfaces. But SC-LBM was not able …

Face Sheet/Core Debonding In Sandwich Composites Under Static And Fatigue Loading, Manjinder Singh Warriach

Wayne State University Dissertations

Delamination growth due to face sheet/core debonding is a major concern due to its inherent weakness in sandwich composites which can be exacerbated due to the presence of flaws. In this research work The primary objective of this research was to characterize the delamination crack growth behavior in E-glass face sheet/polyurethane foam core sandwich composite with pre-existing initial delamination crack at a face sheet/core interface under static and fatigue for mode I and mixed mode loading. For mode I static loading two types of delamination experiments, namely T-peel test and wedge test were implemented to evaluate fracture toughness in polyurethane …

Helmholtz Equation Least Squares Based Near-Field Acoustic Holography With Laser, Wu Zhu

Wayne State University Dissertations

This dissertation presents the HELS based NAH with laser and use normal surface velocity as input in near-field acoustic holography. The conventional HELS based NAH uses acoustic pressure as input to reconstruct sound field quantities, while this modified HELS based NAH with laser utilizes the normal surface velocities measured by LDV to reconstruct the acoustic quantities at interested positions. Theoretical principles of the HELS based NAH with laser have been fully developed and the method has been verified in theoretical perspective. Two theoretical examples verify that HELS based NAH with laser can obtain exactly the same results as analytic solution. …

Analysis And Suppression Of Engine Hood Vibrations Under Random Road Excitations, Hooman Farrokhzadeh

Wayne State University Theses

Vehicle designs and developments must meet safety legislations along with market demands. Safety regulations are mainly concerned with how a vehicle body performs in crashes, during which pedestrian collision is the one of the most important issues. When a vehicle strikes a pedestrian, its engine hood will most likely hit the head of the pedestrian, causing serious injuries. To reduce the severity of the injuries, along with market demands to improve vehicle fuel economy and performance, engineers have considered the design solution of reduction of the vehicle hood thickness (and hence its weight) and the use of advanced light materials. …

Advancement And Validation Of A Plug-In Hybrid Electric Vehicle Model Utilizing Experimental Data From Vehicle Testing, Kevin Lloyd Snyder

Wayne State University Theses

The objective of the research into modeling and simulation was to provide an iterative improvement to the Wayne State EcoCAR 2 team's math-based design tools for use in evaluating different outcomes based on hybrid powertrain architecture tweaks, controls code development and testing. This thesis includes the results of the team's work in the EcoCAR 2 competition for university student teams to create and test a plug-in hybrid electric vehicle for reducing petroleum oil consumption, pollutant emissions, and Green House Gas (GHG) emissions.

Plant model validations and advancements brought the vehicle plant model directionally closer to the actual vehicle's experimental data …

Experimental Investigation On Combustion And Ionization During Cold Starting And Idling Of A Diesel Engine, Sahil Deodatta Sane

Wayne State University Theses

Diesel engine performance during cold starting is very crucial for smooth engine start at undesirable emission level. The development of cold start strategies that improve combustion stability relies mainly on the understanding of the combustion process during the cold starting. Even for modern diesel engines, the conditions during the cold start is far from normal operation characterized by large amount of unburned hydrocarbon emissions and long start to idling time. Thus, the use of an in-cylinder combustion sensor to measure the combustion quality during engine starting can significantly improve engine cold start control strategies. The ion current sensor has the …

The Study Of Ionization In A Military, Heavy-Duty, Diesel Engine, Steven Zielinski

Wayne State University Theses

This thesis is an investigation of ionization in a military, heavy-duty, diesel engine. Ionization is a phenomenon which occurs in both spark-ignited and diesel engines. During the reactions of combustion, charged molecules and electrons are produced. The current produced, ion current, from these charges can be measured. The measurement of ion current can serve as an in-cylinder diagnostic for closed-loop engine control strategies. In this work, a literature review was performed to survey previous work as it pertains to ionization in diesel engines. In addition, a detailed description and comparison of the HEUI injection system was made to HPCR. This …

Effect Of Impact Damage On Compression-Compression Fatigue Behavior Of Sandwich Composites, Ali M. Al-Sharif

Wayne State University Dissertations

The aim of this research work was to investigate the effect of impact damage on in-plane buckling and compression-compression fatigue behavior for a new sandwich structure made from E-glass/epoxy face sheets over end-grain balsa wood core. Low velocity impact tests were carried out using a drop-weight impact tower by impacting the sandwich beam at the center with energy level slightly higher than threshold energy level of 8.8 J. Edge-wise compression static tests were conducted for impacted and non-impacted samples to address energy absorption characteristics of these composites. Analytical and experimental investigations were carried out to measure critical buckling loads and …

Quantification Of Auto-Ignition In Diesel Engines, Umashankar M. Joshi

Wayne State University Dissertations

Efforts have been made previously by researchers to quantify the auto-ignition quality of fuels by calculating global activation energy using Arrhenius plots with data measured for the ignition delay period (ID). Large variation in the activation energy of fuels has been observed even for fuels with closer CN values. More recently, the activation energy values obtained by Kook et al in (2005) on an optical engine do not agree with data obtained in an identical metallic engine by Jayakumar using fuels of same CN.

The disparity in their results can be attributed to the differences in ignition delay (ID) and …

Methodology For Validating Multi-Dimensional Engine Combustion Models And Fuel Surrogates Using An Optically Accessible Compression Ignition Engine, Xin Yu

Wayne State University Dissertations

In response to increasingly stringent engine emissions regulation, three dimensional in-cylinder combustion modeling is increasingly being used as a tool to optimize the combustion process and reduce the cost of experimental testing. Due to the complexity of the physical and chemical interactions involved in the in-cylinder combustion process, the engine combustion model consists of numerous sub-models developed under pre-defined initial and boundary conditions requiring further model calibration depending on different engine applications. Fuel surrogates, one of those sub-models developed for different combustion applications, may not capture all the behavior when applied to the varying temperature-pressure conditions present in a compression …

Edge Fracture Prediction Of Dual Phase Steels With Consideration Of Microstructures, Ming Wen

Wayne State University Dissertations

In recent years, Advanced High Strength Steels (AHSS) have been used for the lightweight structural design and manufacturing in automotive industry. This class of sheet metals are prone to edge fracture during stamping production, and the fracture often occurs at much lower strain than that predicted based on the forming limit curves. The uncertainty in predicting edge fracture represents a great challenge in the application of AHSS. This dissertation is focused on the better understanding of edge fracture phenomenon through experimental observation and computer modeling with the consideration of microstructure effect.

In this dissertation, Hole Expansion (HE) test was used …