Mechanical Engineering Commons^™

Estimating The Inner Ring Defect Size And Residual Service Life Of Freight Railcar Bearings Using Vibration Signatures, Jennifer Lima, Constantine Tarawneh, Jesse Aguilera, Jonas Cuanang

Mechanical Engineering Faculty Publications and Presentations

There are currently two primary wayside detection systems for monitoring the health of freight railcar bearings in the railroad industry: The Trackside Acoustic Detection System (TADS™) and the wayside Hot-Box Detector (HBD). TADS™ uses wayside microphones to detect and alert the train operator of high-risk defects. However, many defective bearings may never be detected by TADS™ since a high-risk defect is a spall which spans about 90% of a bearing’s raceway, and there are less than 30 systems in operation throughout the United States and Canada. HBDs sit on the side of the rail-tracks and use non-contact infrared sensors to …

Optimization Of Railroad Bearing Health Monitoring System For Wireless Utilization, Jonas Cuanang, Constantine Tarawneh, Martin Amaro Jr., Jennifer Lima, Heinrich D. Foltz

Mechanical Engineering Faculty Publications and Presentations

In the railroad industry, systematic health inspections of freight railcar bearings are required. Bearings are subjected to high loads and run at high speeds, so over time the bearings may develop a defect that can potentially cause a derailment if left in service operation. Current bearing condition monitoring systems include Hot-Box Detectors (HBDs) and Trackside Acoustic Detection Systems (TADS™). The commonly used HBDs use non-contact infrared sensors to detect abnormal temperatures of bearings as they pass over the detector. Bearing temperatures that are about 94°C above ambient conditions will trigger an alarm indicating that the bearing must be removed from …

A Study Of The Aeroacoustics Of Swept Propellers For Small Unmanned Aerial Vehicles, Arthur David Wiedemann

Mechanical & Aerospace Engineering Theses & Dissertations

In recent years, small unmanned aerial vehicles (UAVs) have increased in availability and use in both public and commercial sectors. This increased use of small UAVs or “drones” has the unfortunate consequence of introducing excessive noise into communities where they operate. Implementation of noise reduction methods is necessary if we wish to see expanded use of drones in public areas. With electric propulsion, the primary source of noise is the rotor/propeller used in contemporary multi-rotor configurations. In this thesis, the aerodynamics and acoustic behavior of various swept propellers is examined with computational and experimental methods.

A family of propeller geometries …

Maximizing Bass Reflex System Performance Through Optimization Of Port Geometry, Bryce Doll

Honors Undergraduate Theses

A bass-reflex system is a type of loudspeaker design that uses a port or a vent to improve low-frequency performance. The port acts as a Helmholtz resonator which extends the bass response of the system. However, at high drive levels, the air inside the port can become turbulent and cause distortion, noise, and compression. From previous works, it is known that the geometry of the port plays a crucial role in reducing these unwanted effects. This paper serves to provide more insight into optimal port shape by performing several objective tests on a group of 5 different prototype port shapes …