Engineering Commons^™

Vibration-Based Machine Learning Models For Condition Monitoring Of Railroad Rolling Stock, Sergio M. Martinez

Theses and Dissertations

One of the primary causes of rail rolling stock derailments is attributed to bearing and wheel axle failures. The health of train bearings is primarily monitored at target locations through wayside detection systems. This practice is susceptible to bearing failure and potential derailments at points in between these wayside systems. To remedy this, the University Transportation Center for Railway Safety (UTCRS) has developed a wireless onboard monitoring system that can continuously monitor the vibration response, which directly correlates to the health of bearings. This data is used to train regression-based machine learning algorithms and long-term prediction neural networks to predict …

Assessing The Effectiveness And Efficacy Of Wireless Onboard Condition Monitoring Modules In Identifying Defects In Railroad Rolling Stock, Lee R. Cantu

Theses and Dissertations

Many industries have begun shifting into the Internet of Things (IoT) in the 21st century. To help ease this transition for the rail industry, The University Transportation Center for Railway Safety (UTCRS) has partnered with Hum Industrial Technology, Inc. (HUM) to help complete the development of a Wireless Onboard Condition Monitoring system named the ‘Boomerang™’. This product allows customers to schedule proactive maintenance on their railcars to replace defective wheels and/or bearings, saving them time, money and potentially preventing costly catastrophic derailments. The UTCRS research team has established thresholds to determine defective bearings utilizing thermal and mechanical sensors.

The effectiveness …

Hydrophobicity Of Low Temperature Vibrating Surfaces, Christian Fergusson

Theses and Dissertations

This study proposes a method to enhance the anti-icing capabilities of superhydrophobic surfaces by utilizing vibration to further reduce contact time of an impacting droplet in addition to keeping the droplet in the Cassie-Baxter regime, where surface adhesion is lower than the opposing Wenzel regime. We tested this with two methods: by investigating the effects of vibration normal to the plane of a superhydrophobic surface being impacted by water droplets in a room temperature environment, with the surface horizontal in a room temperature environment and tiled in a subzero degree environment. The amplitude and frequency of the vibration were varied …

Experimental Characterization Of Baffle Plate Influence On Turbulent And Cavitation Induced Vibrations In Pipe Flow, Gavin J. Holt

Theses and Dissertations

Turbulent and cavitation induced pipe vibration is a large problem in industry often resulting in pipe failures. This thesis provides an experimental investigation on turbulent flow and cavitation induced pipe vibration caused by sharp edged baffle plates. Due to large pressure losses across a baffle plate, cavitation can result. Cavitation can be destructive to pipe flow in the form of induced pipe wall vibration and cavitation inception. Incipient and critical cavitation numbers are design points that are often used in designing baffle plate type geometries. This investigation presents how these design limits vary with the influencing parameters by exploring a …

Analysis Of Induced Vibrations In Fully-Developed Turbulent Pipe Flow Using A Coupled Les And Fea Approach, Thomas P. Shurtz

Theses and Dissertations

Turbulent flow induced pipe vibration is a phenomenon that has been observed but not fully characterized. This thesis presents research involving numerical simulations that have been used to characterize pipe vibration resulting from fully developed turbulent flow. The vibration levels as indicated by: pipe surface displacement, velocity, and acceleration are characterized in terms of the parameters that exert influence. The influences of geometric and material properties of the pipe are investigated for pipe thickness in the range 1 to 8 mm at a diameter of 0.1015 m. The effects of pipe elastic modulus are explored from 3 to 200 GPa. …

Alleviation Of Buffet-Induced Vibration Using Piezoelectric Actuators, Shawn D. Morganstern

Theses and Dissertations

Buffet-induced vibration has been problematic for aircraft structures for many years. The F-16 ventral fin, while prone to these effects, lends itself well to the evaluation of modern active structural and flow control technologies. The objective of this research was to determine the most critical natural modes of vibration for the F-16 ventral fin and design piezoelectric actuators capable of reducing buffet-induced ventral fin vibration. A finite element model (FEM) for the fin was developed, tuned and optimized to closely match published modal frequencies. Piezoelectric actuator patches were designed using the strain characteristics of the FEM and integrated into the …

Time Aliasing Methods Of Spectrum Estimation, Jason F. Dahl

Theses and Dissertations

Time aliasing methods of spectrum estimation alter the time representation of a signal for the purpose of improving its frequency domain representation. Time aliasing allows characteristics of longer time window functions to be used with shorter DFT length. Windows designed specifically for use with time aliasing have improved properties compared to conventional windows. Many previous uses of time aliasing, including overlap-and-add methods of digital filtering, have focused on the elimination of time aliasing effects in the frequency domain in order to improve the representation of reconstructed signals in the time domain and have not addressed the issues associated with spectrum …

Effect Of Transverse Vibration On The Capillary Limit Of A Wrapped Screen Wick Copper/Water Heat Pipe, Mark C. Charlton

Theses and Dissertations

The effect of transverse vibration on the capillary limit of a copper/water heat pipe with a tightly wrapped screen wick was investigated. The capillary limit was measured over a range of operating temperatures under static conditions. A bench-top shaker was used to provide vibration normal to the longitudinal axis of the pipe, and the capillary limit was measured at vibration frequencies of 30, 250, and 1000 Hz. At each of these frequencies, tests were run at vibration levels of 1.0, 2.5, and 5.0 G. The pipe was maintained at a zero degree inclination angle and power throughput was increased until …

Solution To Eigenvalue Problems Of Antisymmetric Cross-Ply And Antisymmetric Angle-Ply Laminated Plates Using Affine Transformations, Zaffir A. Chaudry

Theses and Dissertations

Using affine transformations and suitably recasting the buckling vibration differential equations, the eigenvalue problem of anti-symmetric cross-ply and antisymmetric angle-ply laminated rectangular plates has been reduced to a function of two strong material constants, the generalized rigidity ratio, whose range is in the closed interval from 0 to 1, and the ratio of principal lamina stiffness. With the reduction in number of constants an exhaustive parameter study of buckling and vibration solution trends, is possible. The buckling coefficients decrease with decreasing value of generalized rigidity ratio for both antisymmetric cross-ply and antisymmetric angle-ply laminates. For a given aspect ratio, and …

The Optimum Design Of A Shock Absorber To Minimize The Force Transmitted To The Supporting Base Of A Vibrating Equipment, J. P. Singh

Theses and Dissertations

The present study involved two types of analyses as a part of the investigation leading to the design of a shock absorber providing optimal vibration control and minimum transmissibility. Those two types of analyses were the following.

Preliminary Design Of A Hydraulic Vibration Machine With Variable Amplitude And Frequency, Using Multistage Amplification And Feedback Control, Melvin Joseph Merrell

Theses and Dissertations

Essentially there are three types of vibration machines mechanical, electrodynamic, and electrohydraulic (hydraulic). Each of these machines has characteristics which make it suitable for particular areas of use.

The Vibration Response Of Laminated Orthotropic Plates, Max E. Waddoups Jr.

Theses and Dissertations

The behavior of anisotropic materials has been the object of much recent research® The high strength to weight ratio needed by aerospace structures has necessitated the use of exotic, composite materials which generally exhibit anisotropic behavior® These materials cannot be fully utilized unless analytical techniques are used which take maximum advantage of their anisotropic behavior.

Analysis Of The Transient Response Of A Flat Rotating Disk By Generalized Transforms, Kenneth Wayne Chase

Theses and Dissertations

The object of this thesis was to lay a foundation for a comprehensive study of the dynamic response of rotating members. This initial phase of the study includes a theoretical investigation and proposes experimental techniques for the determination of the stresses and strains in a thin, rotating disk with a concentric hole, subjected to transient shaft inputs. There are many practical applications of this problem including computor memory storage disks, turbine rotors, grinding wheels, saw blades, gears, optical reflectors, and solar sails for space vehicles.

A Study Of The Vibration Characteristics Of A Thin Shell Hyperbolic Paraboloid, Farrin W. West

Theses and Dissertations

Recent progress in structural engineering has been marked by the increased use of thin shells as load carrying members. In particular, shells of revolution have been widely utilized in the missile industry whereas shells of arbitrary shape have been incorporated in the architectural design of today's modern buildings. Missile applications have been extensively studied both statically and dynamically. However, architechural applications have generally been limited to the statics problem with little consideration being given to the dynamic behavior of these unique structures.