Dr. Tom A. Eppes Profile

Dr. Tom A. Eppes

at Univ of Hartford

SPIE Involvement:

Author

Publications (2)

This will count as one of your downloads.

You will have access to both the presentation and article (if available).

DOWNLOAD NOW

This content is available for download via your institution's subscription. To access this item, please sign in to your personal account.

Email or Username Forgot your username?

Password Forgot your password?

Show

Keep me signed in

No SPIE account? Create an account

Proceedings Article | 19 October 2006 Paper

Noncontact vibration analysis using innovative laser-based methodology

Santiago Noriega, Devdas Shetty, Tom Eppes, Jun Kondo

Proceedings Volume 6375, 63750L (2006) https://doi.org/10.1117/12.686273

KEYWORDS: Vibrometry, Sensors, Doppler effect, Manufacturing, Reliability, Fluctuations and noise, Laser systems engineering, Product engineering, Design for manufacturability, Safety

Read Abstract +

Vibration is a back and forth mechanical motion with a steady, uninterrupted rhythm about an equilibrium point. There are two types of vibration; natural (or free) and forced. Natural vibration occurs as the result of a disturbing force that is applied once and then removed. Forced vibration occurs as a result of a force applied repeatedly to a system. All machines have some amount of forced vibration. However, in some cases this vibration can cause damage to machinery. Understanding vibration is essential for any system that will be exposed to motion. Equipment such as strain gauges and piezoelectric accelerometers have been adequate in measuring vibration in the past; however, due to increased performance requirements and subsequent reductions in vibration, these methods are slowly being replaced by laserbased measurement systems. One reason for the slow transition is that part of the system in these methods must be mounted on the surface of the object being measured which can change the mass thus alter the frequency and mode shape of the vibrating object. At this time however, the high expenses to monitor precision vibration is a challenge, and there is a need for more cost-effective methods of vibration analysis. This paper outlines a lower cost laser-based method of measuring vibration with minimum surface contact.

Proceedings Article | 12 October 2006 Paper

Optical inspection of holes in jet engine blades

Devdas Shetty, Tom Eppes, Nikolay Nazaryan, Jun Kondo, Claudio Campana

Proceedings Volume 6382, 638208 (2006) https://doi.org/10.1117/12.686260

KEYWORDS: Collimators, Optical inspection, Laser drilling, Inspection, Selenium, Sensors, Calibration, Picosecond phenomena, Reflection, Thermal efficiency

Read Abstract +

The need for improved thermal efficiency of jet engines has led to changes in the design of combustor turbine blades. Modern turbine stage inlet temperatures now exceed the melting point temperatures of turbine blade materials. Super alloys, based on nickel, have been developed for use as blades, guide vanes, afterburners etc. To combat and avert blade failure caused by excessive operating temperatures, film cooling has been incorporated into blade design. In film cooling, cool air is bled from the compressor stage, ducted into internal chambers of the turbine blades, and discharged through small holes in the blade walls. This provides a thin, cool, insulating blanket along the external surface of the turbine blade, and large numbers of shaped holes have allowed designers to maximize the cooling effect. This paper explores a new design for measuring the presence and depth of blind holes in turbine blade. In the paper, we examine the inspection techniques currently in use and present a novel optical technique as an alternative. To precisely locate and measure the holes on the turbine blade, an XYZ translation stage is employed. Using a small collimating tube, a micro-beam illuminates each hole in a pre-programmed fashion. Depending on the level of reflected intensity and when it occurs, the presence of a hole bottom is determined. The optical inspection system consists of a laser, motorized micro-positioning stage, collimating tube, optical detector/amplifier, data acquisition software and a customized fixture for manipulating the samples.

My Library

You currently do not have any folders to save your paper to! Create a new folder below.

Folder Name

Folder Description

View contact details

UPDATE YOUR PROFILE

Is this your profile? Update it now.

Sign into your SPIE.org account

Don’t have a profile and want one?

Create an account on SPIE.org

Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks. You are receiving this notice because your organization may not have SPIE eBooks access.*

*Shibboleth/Open Athens users─please sign in to access your institution's subscriptions.

To obtain this item, you may purchase the complete book in print or electronic format on SPIE.org.

ORGANIZATIONAL
Sign in with credentials provided by your organization.

Organizational Username

Organizational Password

Show/Hide Password

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available

Members:

Non-members: ADD TO CART

Keywords/Phrases

Search In:

Publication Years