In-situ simultaneous measurement of strain and temperature in automated fiber placement (AFP) using optical fiber Bragg grating (FBG) sensors

Ebrahim Oromiehie,B Gangadhara Prusty,Paul Compston,Ginu Rajan

doi:10.1080/20550340.2017.1317447

Abstract

There has been a tremendous growth of utilizing automated fiber placement (AFP) to manufacture highly precise components and large structures like fuselage panels and wing skins for high-end applications in aircrafts and next generation of spacecrafts. Consequently, in-situ identification of potential defects and strain level within the laminates is critical to ensure the quality and integrity of the final product. In this study, optical fiber Bragg grating sensors (FBGs) have been implemented as an on-line monitoring technique for simultaneous measurement of strain and temperature in AFP. In addition, it is also shown that, the embedded FBG sensors can remain within the laminate for continuous health monitoring after manufacturing process toward the identification of crack induced acoustic emissions.

Highlights

The capabilities of automated fiber placement (AFP) machine for making bespoke components along with increasing productivity have provided wider range of application for the AFP in comparison with the other manufacturing methods.[1]
Parlevliet et al 4 have demonstrated how a strain gage was melt-embedded in the center of the surface plies of a unidirectional carbon fiber/ PEEK laminate to measure the formation of residual stresses from thermal and crystallization effects
Daniel and Liber[5] have studied the effect of laminate construction on residual stresses in graphite/polyimide composite using thermal resistance strain gages in which high temperature withstanding strain gage is placed between the plies and cured

Summary

Introduction

The capabilities of automated fiber placement (AFP) machine for making bespoke components along with increasing productivity have provided wider range of application for the AFP in comparison with the other manufacturing methods.[1]. Tsouvalis et al.[6] highlighted that the strain gages are not reliable for thermoplastic composites due to their high processing temperature. The machine includes compaction roller, heating system, and a robotic arm, which is computer controlled.[24,25] During the placement process, an incoming tape is delivered to compaction roller while temperature is being introduced through a heat source to the laminate. A hot gas trorch (HGT) is used as heat source which delivers high temperature nitrogen around the tape at the nip point. A number of parameters influence the quality of laminated composite manufacturing using the AFP machine include HGT temperature, hot gas flow rate, consolidation pressure, ply orientation, and lay-up speed/deposition rate.

Objectives

Methods

Conclusion