Engineering Commons^™

Sensor Comparison For Low-Cost Dynamic Force Measurement In Milling, Zachary Mason

Masters Theses

Machine cutting forces are commonly measured using piezoelectric dynamometers. Such dynamometers can be prohibitively expensive and may still require extensive post processing. Previous work used a low-cost single degree of freedom constrained motion dynamometer (CMD) in conjunction with a knife edge sensor to determine the cutting forces through inverse force filtering. In that approach, the measured displacement of the CMD was transformed into the frequency domain by the fast Fourier transform (FFT) and convolved with the inverted receptance frequency response function (FRF) to yield force in the frequency domain. The force was then converted to the time domain using the …

Digital Cutting Force Modeling For Milling Operations, Timothy T. No

Doctoral Dissertations

Process improvement in milling through improved understanding of machining dynamics is an on-going research endeavor. The objective of this project is to advance digital modeling of the milling process by incorporating tool-specific geometry in the machining analysis. Structured light scanning will be used to perform tool geometry measurements and produce a 3D model. The 3D model data will include the spatial location of the cutting edges, as well as the rake and relief profiles from the tool cross section. The rake and relief profiles will be imported, together with the work material flow stress model, into a finite element analysis …

Displacement-Based Dynamometer For Milling Force Measurement, Michael F. Gomez

Doctoral Dissertations

This project will study the design and testing of a low-cost dynamometer for milling dynamic force measurement. The monolithic design is based on constrained-motion/flexure-based kinematics, where force is inferred from displacement measured using a low-cost optical interrupter (i.e., a knife edge that partially interrupts the light beam in an emitter-detector pair). The time-dependent displacement of the dynamometer’s moving platform caused by the milling force is converted to the frequency domain, multiplied by the inverse of the dynamometer’s ideally single degree of freedom (SDOF) frequency response function (FRF), and converted back into the time-domain to obtain the time-dependent cutting force. The …

The Water Entry Of Slender Axisymmetric Bodies: Forces, Trajectories And Acoustics, Kyle Gordon Bodily

Theses and Dissertations

Free surface water entry of various objects has been studied using high-speed images and image processing techniques for decades. This thesis studies the forces, velocities, and trajectories of slender axisymmetric projectiles using an embedded inertial measurement unit (IMU). Three nose shapes (cone, ogive, and flat) were used in the study. Additionally, the projectiles were tested at vertical and oblique impact angles with different surface conditions. One-half of each projectile was coated down the centerline with a hydrophobic spray, creating a half hydrophobic, half hydrophilic case. The trajectory of this half-and-half case impacting vertically was compared to the trajectory of symmetrically …

Energy Dissipation Caused By Asphalt Roadway Gouges For Use In Accident Reconstruction, Charles L. Crosby

Theses and Dissertations

In reconstruction of on-roadway vehicle accidents, roadway surface gouges and the forces and energy attributed to the related vehicle components become important keys to resolving an accurate accident reconstruction. These roadway gouge forces vary depending upon such factors as surface temperature and the velocity and geometry of the gouging mechanism. Accounting for the forces applied to vehicle components and the energy dissipated from such forces can be helpful in accident reconstruction where supporting data exists. This research documents the force necessary to create a given roadway gouge geometry. Controlled pavement gouging tests were performed using roadway surface temperature and gouging …

Cross Sections Used To Elucidate Differences In Wavelet Transforms Of Ground Force Reactions, Wesley John Orme

Boise State University Theses and Dissertations

A study done for the Centers for Disease Control (CDC) found that over 50% of sports related injuries are to the lower extremities [1] with additional studies indicating that females, adolescent through collegiate, have a higher rate of lower extremity sports related injuries than males [2-4]. Conditions surrounding non-contact injuries can be analyzed using ground reaction force (GRF) data from force plates during unanticipated single leg drops, however, the expected gender differences in GRF may not be apparent when viewing data independently in the time or frequency domains.

Graphing the results of a wavelet transform, currently used by scientific, medical, …

Large 3-D Deflection And Force Analysis Of Lateral Torsional Buckled Beams, Robert Parley Chase

Theses and Dissertations

This thesis presents research on the force and deflection behavior of beams with rectangular cross-sections undergoing lateral torsional buckling. The large 3-D deflection path of buckling beam tips was closely approximated by circular arcs in two planes. A new chain algorithm element was created from pseudo-rigid-body segments and used in a chain calculation that accurately predicted the force deflection relationship of beams with large 3-D deflections.

Design Of Piezoresistive Mems Force And Displacement Sensors, Tyler Lane Waterfall

Theses and Dissertations

MEMS (MicroElectroMechanical Systems) sensors are used in acceleration, flow, pressure and force sensing applications on the micro and macro levels. Much research has focused on improving sensor precision, range, reliability, and ease of manufacture and operation. One exciting possibility for improving the capability of micro sensors lies in exploiting the piezoresistive properties of silicon, the material of choice in many MEMS fabrication processes. Piezoresistivity—the change of electrical resistance due to an applied strain—is a valuable material property of silicon due to its potential for high signal output and on-chip and feedback-control possibilities. However, successful design of piezoresistive micro sensors requires …

High-Torque Capacity Compliant Centrifugal Clutches, Ryan G. Weight

Theses and Dissertations

This thesis developed high-torque-capacity floating opposing arm clutches that are manufactured with standard economical manufacturing processes, while maintaining critical performance characteristics. Contact engagement speed and torque capacity models were created for the Hoffco-Comet, floating-opposing-arm (FOA), and floating 1 (F1) clutches. Sensitivity analyses were performed to identify key design parameters. A robust compliant FOA clutch was designed by minimizing the tolerance for both contact engagement speed and torque capacity. The robust design insures that the clutch will operate within the prescribed application constraints. Additional modeling showed that using a layered clutch would significantly tighten the contact engagement speed and torque performance …