Engineering Commons^™

Theoretical Analysis Of Torsionally Vibrating Microcantilevers For Chemical Sensor Applications In Viscous Liquids, Tao Cai

Dissertations (1934 -)

Dynamically driven microcantilevers excited in the transverse (or out-of-plane) direction are widely used as highly sensitive chemical sensing platforms in various applications. While these devices work very well in air, their performance in liquids is not efficient because of the combination of increased viscous damping and effective fluid mass. In order to improve the characteristics of microcantilevers in liquid environments, some other vibration modes such as the torsional mode and lateral (or in-plane) flexural mode have been proposed.
In this work, the characteristics of torsionally vibrating rectangular microcantilevers with length L, width b and thickness h in viscous liquids are …

An Investigation Of Phase-Change Effects During Rapid Compression Machine Experiments, Colin Banyon

Master's Theses (2009 -)

Rapid compression machines (RCMs) are well characterized laboratory scale devices capable of achieving internal combustion (IC) engine relevant thermodynamic environments. These machines are often used to collect ignition delay times as targets for gas-phase chemical kinetic fuel autoigntion models. Modern RCMs utilize creviced piston(s) to improve charge homogeneity and allow for an adequate validation of detailed chemistry mechanisms against experiments using computationally efficient, homogeneous reactor models (HRMs). Conventionally, experiments are preformed by introducing a premixed gas of fuel + oxidizer + diluent into the machine, which is compressed volumetrically via a piston. Experiments investigating low-vapor pressure fuels (e.g. diesels, biodiesels, …

Effects Of Bit Type On Maximum Torque And Axial Force Using Manual Screwdrivers, Mark Hickok

Master's Theses (2009 -)

The screwdriver is a tool that has been among the most widely used hand tools for decades and continues to be used in the workplace to perform a variety of fastening tasks. Advancements in fastener technology have been complemented by the development of new types of screwdriver bits. While designs may vary, so do the force application requirements placed on the tool user. The primary objective of this experiment is to analyze the relationship between user torque and screwdriver bit design. A further objective is to utilize the results to develop an effort metric by which bits of different designs …

Numerical Simulation Model On Irreversibility Of Shock-Wave Process, Longhao Huang

Master's Theses (2009 -)

The objective of this research is to develop a better understanding of the irreversibilities associated with the shock compaction of matter, especially as a result of impact. Due to complex shock processes, experimentation alone cannot fix the material state, since properties such as internal energy, entropy as well as the shock process are not measurable. Thus, in addition to experimentation, analytical and numerical methods are also used to completely characterize the shock process, although they are restricted by underlying constitutive assumptions. Instead of using artificial irreversibility, such as artificial viscosity to simplify and stabilize the numeric shock model, this work …

Admittance Selection For Force Guided Assembly With Optimal Motion, Fernando Rodriguez Anton

Master's Theses (2009 -)

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Current robots lack the precise relative positioning necessary to complete automatic assembly tasks. Several solutions have been proposed. Some approaches use complex vision and force sensing systems to generate corrective motion if misalignment is present in the assembly task. Other solutions rely on generating elastic behavior, known as compliance, between the end eector and the held movable part. This compliant mechanism helps guide the movable part of the assembly into its proper position. The project focuses on designing a process by which passive compliant systems can achieve successful assembly for a range of misalignment and generate error-reducing motion that …

Profile Synthesis Of Planar Variable Joints, Brian James Slaboch

Dissertations (1934 -)

Reconfigurable mechanisms provide quick changeover and reduced costs for low volume manufacturing applications. In addition, these mechanisms provide added flexibility in the context of a constrained environment. A subset of planar reconfigurable mechanisms use variable joints to provide this added adaptability.

In this dissertation, the profile synthesis of planar variable joints that change from a rotational motion to a translational motion was investigated. A method was developed to perform automated profile synthesis. It was shown that combinations of higher variable joints can be used to create kinematically equivalent variable joints that are geometrically different.

The results were used to create …

Dynamic Modeling Of A Belt Driven Electromechanical Xy Plotter Cutter, Joseph V. Prisco

Master's Theses (2009 -)

Current industrial XY plotter cutters that use a belt driven gantry for the X motion and media feed for the Y motion sometimes have performance issues in cutting out high quality shapes. Mathematical models for these plotter cutters are not publicly available and thus the parameters critical to cut quality are not well understood. This thesis develops a dynamic, electromechanical model for the gantry arm and media feed using first principles and a non-linear friction model. These models are independently simulated and experimentally verified. In order to verify the effectiveness of the individual models, they are combined with a control …

Flame Temperature Imaging Of A Low Nox Burner Via Laser Rayleigh Scattering, Nicholas A. Smith

Master's Theses (2009 -)

Federal and global legislation are requiring increasingly stringent emission regulation on household appliances and in particular water heater burners. Emissions like NOx (NO and NO2) are a growing concern due to their adverse health effects and contribution to tropospheric ozone, acid rain, and smog formation. As NOx is more closely controlled, appliance manufacturers are developing low emission burners for use in water heaters.

Flame temperature is strongly correlated to NOx production. Hence, characterizing flame temperatures in new burners is a key part of improving upon burners used today and the development of future burners. Temperature measurements applied to a new, …

A Multi-Scale Approach To A Greater Understanding Of The Behavior Of Heterogeneous Materials Under Dynamic Loading, Andrew J. Van Vooren

Master's Theses (2009 -)

The penetration of granular materials is of interest to a variety of different fields, and is an active area of research. The objective of this project is to gain understanding of the dynamics of a projectile penetrating into a granular material. To do this, experiments were run and a numerical model was created.

A dart gun was used to accelerate an aluminum dart to velocities around 100 m/s, which then impacted a target tank filled with Ottawa sand. The dart flew along a view window, which allowed for a recording of the penetration event using a high speed camera. Pressure …

Analysis Of Laminated Anisotropic Plates And Shells Via A Modified Complementary Energy Principle Approach, Martin Claude Domfang

Dissertations (1934 -)

The present work is concerned with the finite element structural analysis of laminated anisotropic plates and shells. New elements based on a modified complementary energy principle are proposed to improve the analysis of such composite structures. Third order deformation plate and shell models incorporating a convergence parameter are developed to govern the general displacement field.

An eight-node isoparametric quadrilateral element with two independent cross-sectional rotations and three normal displacements is utilized to describe the displacement field. The present modified complementary energy formulation incorporates a number of in-plane strain functions of various orders. The corresponding in-plane stresses for each lamina are …