High-frequency noncontact ultrasonic analysis of materials: introduction and applications

Mahesh C. Bhardwaj; Gary F. Stead

doi:10.1117/12.435556

3 August 2001 High-frequency noncontact ultrasonic analysis of materials: introduction and applications

Mahesh C. Bhardwaj, Gary F. Stead

Proceedings Volume 4336, Nondestructive Evaluation of Materials and Composites V; (2001) https://doi.org/10.1117/12.435556
Event: 6th Annual International Symposium on NDE for Health Monitoring and Diagnostics, 2001, Newport Beach, CA, United States

Abstract

High frequency Non-Contact Ultrasonic (NCU) analysis of materials has been a persistent dream of materials engineers and scientists. However, a natural impediment to NCU is the exorbitant acoustic impedance mismatch between air and the test materials. The magnitude of this obstacle is further exacerbated in the Megahertz frequencies, necessary for high resolution, detectability, and sensitivity. This air- material acoustic impedance barrier has been successfully broken by virtue of our phenomenally high transduction piezoelectric transducers (from 100 kHz to 5 MHz) and equally high sensitivity non-contact analyzer (> 150 dB dynamic range and nano-second time-of-flight accuracy). It is now possible to transmit ultrasound in virtually all materials and all states of matter (with the exception of vacuum) without any contact with them. Unlike the conventional contact ultrasound, with NCU, characterization of materials is easy in the early stages of their formation and processing. This includes powders, green ceramics, consolidated powder metals, composite pre-pregs, and polymerization process. In this paper we provide a systematic introduction to the significant of materials characterization, NCU transducers and an analyzer. Also provided are a number of examples of NCU analysis of a wide range of materials, including their internal and surface characteristics. Materials are characterized for thickness, velocity (density and mechanical properties), microstructure, delaminations, defects, etc.

Citation Download Citation

Mahesh C. Bhardwaj and Gary F. Stead "High-frequency noncontact ultrasonic analysis of materials: introduction and applications", Proc. SPIE 4336, Nondestructive Evaluation of Materials and Composites V, (3 August 2001); https://doi.org/10.1117/12.435556

ACCESS THE FULL ARTICLE

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