Event Title

Study of Generation Mechanisms for Laser Ultrasonics

Location

Snowbird, UT, USA

Start Date

1-1-1999 12:00 AM

Description

The aerospace industry is beginning to use advanced composite materials for primary load bearing structures and their failure mechanisms must be better understood to predict their behavior in service. The Combined Loads Tests (COLTS) facility is being constructed at the NASA Langley Research Center to characterize these failure mechanisms. Laser based ultrasonic NDE can monitor the samples during dynamic loading without interfering with the structural tests. However, the constraints of implementing laser ultrasound in a structures laboratory reduces the efficiency of the technique. The system has to be “eye-safe” because many people will be present during the structural tests. Consequently, laser light has to be delivered through fiber optics and a significant amount of light is lost. Also, the nature of the composite materials makes laser ultrasonic inspection difficult. The composites of interest are formed from woven layers that are stitched through the laminate thickness and bound in a resin matrix. These materials attenuate ultrasound strongly and exhibit a high degree of scattering. In this paper, we describe a field-deployable laser based ultrasonic NDE system that we developed to investigate structures during testing in the COLTS facility. We illustrate the design constraints that reduced efficiency and present some ultrasonic data from thick stitched composites.

Book Title

Review of Progress in Quantitative Nondestructive Evaluation

Volume

18A

Chapter

Chapter 1: Elastic Waves and Ultrasonic Techniques

Section

Laser Ultrasonics and Applications

Pages

293-300

DOI

10.1007/978-1-4615-4791-4_36

Language

en

File Format

application/pdf

This document is currently not available here.

Share

COinS
 
Jan 1st, 12:00 AM

Study of Generation Mechanisms for Laser Ultrasonics

Snowbird, UT, USA

The aerospace industry is beginning to use advanced composite materials for primary load bearing structures and their failure mechanisms must be better understood to predict their behavior in service. The Combined Loads Tests (COLTS) facility is being constructed at the NASA Langley Research Center to characterize these failure mechanisms. Laser based ultrasonic NDE can monitor the samples during dynamic loading without interfering with the structural tests. However, the constraints of implementing laser ultrasound in a structures laboratory reduces the efficiency of the technique. The system has to be “eye-safe” because many people will be present during the structural tests. Consequently, laser light has to be delivered through fiber optics and a significant amount of light is lost. Also, the nature of the composite materials makes laser ultrasonic inspection difficult. The composites of interest are formed from woven layers that are stitched through the laminate thickness and bound in a resin matrix. These materials attenuate ultrasound strongly and exhibit a high degree of scattering. In this paper, we describe a field-deployable laser based ultrasonic NDE system that we developed to investigate structures during testing in the COLTS facility. We illustrate the design constraints that reduced efficiency and present some ultrasonic data from thick stitched composites.