Monitoring Cure Properties of Out-of-Autoclave BMI Composites using IFPI Sensor


A non-destructive technique for inspection of a Bismaleimide (BMI) composite is presented using an optical fiber sensor. High performance BMI composites are used for Aerospace application for their mechanical strength. They are also used as an alternative to toughened epoxy resins. A femtosecond-laser-inscribed Intrinsic Fabry-Perot Interferometer (IFPI) sensor is used to perform real time cure monitoring of a BMI composite. The composite is cured using the out-of-autoclave (OOA) process. The IFPI sensor was used for in-situ monitoring; different curing stages are analyzed throughout the curing process. Temperature-induced-strain was measured to analyze the cure properties. The IFPI structure comprises of two reflecting mirrors inscribed on the core of the fiber using a femtosecond-laser manufacturing process. The manufacturing process makes the sensor thermally stable and robust for embedded applications. The sensor can withstand very high temperatures of up to 850 °C. The temperature and strain sensitivities of embedded IFPI sensor were measured to be 1.4 pm/μepsilon and 0.6 pm/μepsilon respectively.

Meeting Name

SPIE Smart Structures and Materials + Nondestructive Evaluation and Health Monitoring (2016: Mar. 21-24, Las Vegas, NV)


Electrical and Computer Engineering

Second Department

Mechanical and Aerospace Engineering

Keywords and Phrases

Aerospace applications; Epoxy resins; Fabry-Perot interferometers; Laser mirrors; Manufacture; Nondestructive examination; Optical fibers; Pressure vessels; Ultrashort pulses; Bismaleimides; Cure monitoring; Embedded application; IFPI; Intrinsic Fabry-Perot interferometers; Manufacturing process; Non-destructive technique; Out of autoclaves; Curing; Cure monitoring; Femtosecond-laser

International Standard Book Number (ISBN)


International Standard Serial Number (ISSN)

0277-786X; 1996-756X

Document Type

Article - Conference proceedings

Document Version


File Type





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Publication Date

01 Mar 2016