Location

Brunswick, ME

Start Date

1-1-1990 12:00 AM

Description

The fabrication process of recently developed advanced technology hybrid structures has placed a demand on methods to monitor the state of cure of resins and epoxies commonly used in composite materials. Such monitoring allows in-situ process control insuring homogeneous structural integrity. Furthermore, fabrication costs can be reduced by avoiding the need to over cure“ the composite specimens. Existing techniques such as differential scanning calorimetry (DSC), optical spectroscopy, and dielectric spectroscopy lack the in-situ capabilities required to monitor localized cure state. Other methods, including ultrasonic wave monitoring, are absolute in nature, require frequent calibration, and involve complex measurement systems for monitoring localized cure state [1–3]. We propose to expand upon a principle recently suggested by M. A. Afromowitz, in which optical waveguides made out of the hybrid resin material itself are embedded within the specimen to be monitored [4]. Such implementation exploits some of the advantages of fiber optic sensing techniques, while avoiding the incorporation of “foreign materials” which might cause inhomogeneities in the composite structure.

Book Title

Review of Progress in Quantitative Nondestructive Evaluation

Volume

9B

Chapter

Chapter 9: Manufacturing and Process Control

Pages

2047-2053

Language

en

File Format

application/pdf

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Jan 1st, 12:00 AM

Optical Fiber Methods for Autoclave and Epoxy Cure Monitoring

Brunswick, ME

The fabrication process of recently developed advanced technology hybrid structures has placed a demand on methods to monitor the state of cure of resins and epoxies commonly used in composite materials. Such monitoring allows in-situ process control insuring homogeneous structural integrity. Furthermore, fabrication costs can be reduced by avoiding the need to over cure“ the composite specimens. Existing techniques such as differential scanning calorimetry (DSC), optical spectroscopy, and dielectric spectroscopy lack the in-situ capabilities required to monitor localized cure state. Other methods, including ultrasonic wave monitoring, are absolute in nature, require frequent calibration, and involve complex measurement systems for monitoring localized cure state [1–3]. We propose to expand upon a principle recently suggested by M. A. Afromowitz, in which optical waveguides made out of the hybrid resin material itself are embedded within the specimen to be monitored [4]. Such implementation exploits some of the advantages of fiber optic sensing techniques, while avoiding the incorporation of “foreign materials” which might cause inhomogeneities in the composite structure.